X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/6601e61aa18bf4f09af135ff61fc7f4771d23b06..0a7de7458d150b5d4dffc935ba399be265ef0a1a:/bsd/kern/kern_exec.c diff --git a/bsd/kern/kern_exec.c b/bsd/kern/kern_exec.c index 29d2bd13f..fea51a172 100644 --- a/bsd/kern/kern_exec.c +++ b/bsd/kern/kern_exec.c @@ -1,23 +1,29 @@ /* - * Copyright (c) 2000-2004 Apple Computer, Inc. All rights reserved. - * - * @APPLE_LICENSE_HEADER_START@ - * - * The contents of this file constitute Original Code as defined in and - * are subject to the Apple Public Source License Version 1.1 (the - * "License"). You may not use this file except in compliance with the - * License. Please obtain a copy of the License at - * http://www.apple.com/publicsource and read it before using this file. - * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * Copyright (c) 2000-2013 Apple Inc. All rights reserved. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_START@ + * + * This file contains Original Code and/or Modifications of Original Code + * as defined in and that are subject to the Apple Public Source License + * Version 2.0 (the 'License'). You may not use this file except in + * compliance with the License. The rights granted to you under the License + * may not be used to create, or enable the creation or redistribution of, + * unlawful or unlicensed copies of an Apple operating system, or to + * circumvent, violate, or enable the circumvention or violation of, any + * terms of an Apple operating system software license agreement. + * + * Please obtain a copy of the License at + * http://www.opensource.apple.com/apsl/ and read it before using this file. + * + * The Original Code and all software distributed under the License are + * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, - * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the - * License for the specific language governing rights and limitations - * under the License. - * - * @APPLE_LICENSE_HEADER_END@ + * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. + * Please see the License for the specific language governing rights and + * limitations under the License. + * + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ /* @@ -26,8 +32,6 @@ * All rights reserved. The CMU software License Agreement specifies * the terms and conditions for use and redistribution. */ - -#include /*- * Copyright (c) 1982, 1986, 1991, 1993 @@ -68,7 +72,14 @@ * * from: @(#)kern_exec.c 8.1 (Berkeley) 6/10/93 */ +/* + * NOTICE: This file was modified by SPARTA, Inc. in 2005 to introduce + * support for mandatory and extensible security protections. This notice + * is included in support of clause 2.2 (b) of the Apple Public License, + * Version 2.0. + */ #include +#include #include #include @@ -81,7 +92,7 @@ #include #include #include -#include +#include #include #include #include @@ -91,103 +102,199 @@ #include #include #include -#include /* shmexec() */ -#include /* ubc_map() */ +#include +#include +#if SYSV_SHM +#include /* shmexec() */ +#endif +#include /* ubc_map() */ +#include +#include +#include +#include +#include +#include -#include +#include + +#include + +#include #include +#include #include +#include #include #include #include #include +#include /* thread_wakeup() */ +#include +#include +#include +#include +#include +#include + +#include + +#if CONFIG_MACF +#include +#include +#endif + #include #include -#include +#include #include -#include -#include +#include +#include + +#include + +#include + +#include + +#if CONFIG_MEMORYSTATUS +#include +#endif + +#include + +extern boolean_t vm_darkwake_mode; + +#if CONFIG_DTRACE +/* Do not include dtrace.h, it redefines kmem_[alloc/free] */ +extern void dtrace_proc_exec(proc_t); +extern void (*dtrace_proc_waitfor_exec_ptr)(proc_t); + +/* + * Since dtrace_proc_waitfor_exec_ptr can be added/removed in dtrace_subr.c, + * we will store its value before actually calling it. + */ +static void (*dtrace_proc_waitfor_hook)(proc_t) = NULL; + +#include +#endif + +/* support for child creation in exec after vfork */ +thread_t fork_create_child(task_t parent_task, + coalition_t *parent_coalition, + proc_t child_proc, + int inherit_memory, + int is_64bit_addr, + int is_64bit_data, + int in_exec); +void vfork_exit(proc_t p, int rv); +extern void proc_apply_task_networkbg_internal(proc_t, thread_t); +extern void task_set_did_exec_flag(task_t task); +extern void task_clear_exec_copy_flag(task_t task); +proc_t proc_exec_switch_task(proc_t p, task_t old_task, task_t new_task, thread_t new_thread); +boolean_t task_is_active(task_t); +boolean_t thread_is_active(thread_t thread); +void thread_copy_resource_info(thread_t dst_thread, thread_t src_thread); +void *ipc_importance_exec_switch_task(task_t old_task, task_t new_task); +extern void ipc_importance_release(void *elem); /* * Mach things for which prototypes are unavailable from Mach headers */ -void ipc_task_reset( - task_t task); -void ipc_thread_reset( - thread_t thread); +void ipc_task_reset( + task_t task); +void ipc_thread_reset( + thread_t thread); +kern_return_t ipc_object_copyin( + ipc_space_t space, + mach_port_name_t name, + mach_msg_type_name_t msgt_name, + ipc_object_t *objectp); +void ipc_port_release_send(ipc_port_t); + +#if DEVELOPMENT || DEBUG +void task_importance_update_owner_info(task_t); +#endif extern struct savearea *get_user_regs(thread_t); +__attribute__((noinline)) int __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(mach_port_t task_access_port, int32_t new_pid); #include #include #include #include +#include #include #include #include -#if KTRACE -#include -#endif #include +#include + /* - * SIZE_MAXPTR The maximum size of a user space pointer, in bytes - * SIZE_IMG_STRSPACE The available string space, minus two pointers; we - * define it interms of the maximum, since we don't - * know the pointer size going in, until after we've - * parsed the executable image. + * EAI_ITERLIMIT The maximum number of times to iterate an image + * activator in exec_activate_image() before treating + * it as malformed/corrupt. */ -#define SIZE_MAXPTR 8 /* 64 bits */ -#define SIZE_IMG_STRSPACE (NCARGS - 2 * SIZE_MAXPTR) +#define EAI_ITERLIMIT 3 -int app_profile = 0; +/* + * For #! interpreter parsing + */ +#define IS_WHITESPACE(ch) ((ch == ' ') || (ch == '\t')) +#define IS_EOL(ch) ((ch == '#') || (ch == '\n')) extern vm_map_t bsd_pageable_map; -extern struct fileops vnops; +extern const struct fileops vnops; +extern int nextpidversion; + +#define USER_ADDR_ALIGN(addr, val) \ + ( ( (user_addr_t)(addr) + (val) - 1) \ + & ~((val) - 1) ) + +/* Platform Code Exec Logging */ +static int platform_exec_logging = 0; -#define ROUND_PTR(type, addr) \ - (type *)( ( (unsigned)(addr) + 16 - 1) \ - & ~(16 - 1) ) +SYSCTL_DECL(_security_mac); -struct image_params; /* Forward */ +SYSCTL_INT(_security_mac, OID_AUTO, platform_exec_logging, CTLFLAG_RW, &platform_exec_logging, 0, + "log cdhashes for all platform binary executions"); + +static os_log_t peLog = OS_LOG_DEFAULT; + +struct image_params; /* Forward */ +static int exec_activate_image(struct image_params *imgp); static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp); static int load_return_to_errno(load_return_t lrtn); static int execargs_alloc(struct image_params *imgp); static int execargs_free(struct image_params *imgp); static int exec_check_permissions(struct image_params *imgp); static int exec_extract_strings(struct image_params *imgp); +static int exec_add_apple_strings(struct image_params *imgp, const load_result_t *load_result); static int exec_handle_sugid(struct image_params *imgp); static int sugid_scripts = 0; -SYSCTL_INT (_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW, &sugid_scripts, 0, ""); -static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack, - int customstack, struct proc *p); +SYSCTL_INT(_kern, OID_AUTO, sugid_scripts, CTLFLAG_RW | CTLFLAG_LOCKED, &sugid_scripts, 0, ""); +static kern_return_t create_unix_stack(vm_map_t map, load_result_t* load_result, proc_t p); static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size); - -/* XXX forward; should be in headers, but can't be for one reason or another */ -extern int grade_binary(cpu_type_t exectype, cpu_subtype_t execsubtype); -extern void vfork_return(thread_t th_act, - struct proc * p, - struct proc *p2, - register_t *retval); - - -extern char classichandler[32]; -extern uint32_t classichandler_fsid; -extern long classichandler_fileid; - +static void exec_resettextvp(proc_t, struct image_params *); +static int check_for_signature(proc_t, struct image_params *); +static void exec_prefault_data(proc_t, struct image_params *, load_result_t *); +static errno_t exec_handle_port_actions(struct image_params *imgp, boolean_t * portwatch_present, ipc_port_t * portwatch_ports); +static errno_t exec_handle_spawnattr_policy(proc_t p, int psa_apptype, uint64_t psa_qos_clamp, uint64_t psa_darwin_role, + ipc_port_t * portwatch_ports, int portwatch_count); /* - * exec_add_string + * exec_add_user_string * * Add the requested string to the string space area. * * Parameters; struct image_params * image parameter block * user_addr_t string to add to strings area - * uio_seg segment where string is located + * int segment from which string comes + * boolean_t TRUE if string contributes to NCARGS * * Returns: 0 Success * !0 Failure errno from copyinstr() @@ -195,55 +302,77 @@ extern long classichandler_fileid; * Implicit returns: * (imgp->ip_strendp) updated location of next add, if any * (imgp->ip_strspace) updated byte count of space remaining + * (imgp->ip_argspace) updated byte count of space in NCARGS */ static int -exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg) +exec_add_user_string(struct image_params *imgp, user_addr_t str, int seg, boolean_t is_ncargs) { - int error = 0; + int error = 0; + + do { + size_t len = 0; + int space; + + if (is_ncargs) { + space = imgp->ip_argspace; /* by definition smaller than ip_strspace */ + } else { + space = imgp->ip_strspace; + } - do { - size_t len = 0; - if (imgp->ip_strspace <= 0) { + if (space <= 0) { error = E2BIG; break; } - if (IS_UIO_SYS_SPACE(seg)) { - char *kstr = CAST_DOWN(char *,str); /* SAFE */ - error = copystr(kstr, imgp->ip_strendp, imgp->ip_strspace, &len); - } else { - error = copyinstr(str, imgp->ip_strendp, imgp->ip_strspace, - &len); + + if (!UIO_SEG_IS_USER_SPACE(seg)) { + char *kstr = CAST_DOWN(char *, str); /* SAFE */ + error = copystr(kstr, imgp->ip_strendp, space, &len); + } else { + error = copyinstr(str, imgp->ip_strendp, space, &len); } + imgp->ip_strendp += len; imgp->ip_strspace -= len; + if (is_ncargs) { + imgp->ip_argspace -= len; + } } while (error == ENAMETOOLONG); return error; } +/* + * dyld is now passed the executable path as a getenv-like variable + * in the same fashion as the stack_guard and malloc_entropy keys. + */ +#define EXECUTABLE_KEY "executable_path=" + /* * exec_save_path * * To support new app package launching for Mac OS X, the dyld needs the * first argument to execve() stored on the user stack. * - * Save the executable path name at the top of the strings area and set + * Save the executable path name at the bottom of the strings area and set * the argument vector pointer to the location following that to indicate * the start of the argument and environment tuples, setting the remaining - * string space count to the size of the string area minus the path length - * and a reserve for two pointers. + * string space count to the size of the string area minus the path length. * * Parameters; struct image_params * image parameter block * char * path used to invoke program - * uio_seg segment where path is located + * int segment from which path comes * * Returns: int 0 Success - * !0 Failure: error number + * EFAULT Bad address + * copy[in]str:EFAULT Bad address + * copy[in]str:ENAMETOOLONG Filename too long + * * Implicit returns: * (imgp->ip_strings) saved path * (imgp->ip_strspace) space remaining in ip_strings - * (imgp->ip_argv) beginning of argument list * (imgp->ip_strendp) start of remaining copy area + * (imgp->ip_argspace) space remaining of NCARGS + * (imgp->ip_applec) Initial applev[0] * * Note: We have to do this before the initial namei() since in the * path contains symbolic links, namei() will overwrite the @@ -253,24 +382,26 @@ exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg) * unacceptable for dyld. */ static int -exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg) +exec_save_path(struct image_params *imgp, user_addr_t path, int seg, const char **excpath) { int error; - size_t len; - char *kpath = CAST_DOWN(char *,path); /* SAFE */ + size_t len; + char *kpath; - imgp->ip_strendp = imgp->ip_strings; - imgp->ip_strspace = SIZE_IMG_STRSPACE; + // imgp->ip_strings can come out of a cache, so we need to obliterate the + // old path. + memset(imgp->ip_strings, '\0', strlen(EXECUTABLE_KEY) + MAXPATHLEN); len = MIN(MAXPATHLEN, imgp->ip_strspace); - switch( seg) { + switch (seg) { case UIO_USERSPACE32: - case UIO_USERSPACE64: /* Same for copyin()... */ - error = copyinstr(path, imgp->ip_strings, len, &len); + case UIO_USERSPACE64: /* Same for copyin()... */ + error = copyinstr(path, imgp->ip_strings + strlen(EXECUTABLE_KEY), len, &len); break; - case UIO_SYSSPACE32: - error = copystr(kpath, imgp->ip_strings, len, &len); + case UIO_SYSSPACE: + kpath = CAST_DOWN(char *, path); /* SAFE */ + error = copystr(kpath, imgp->ip_strings + strlen(EXECUTABLE_KEY), len, &len); break; default: error = EFAULT; @@ -278,27 +409,58 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg) } if (!error) { + bcopy(EXECUTABLE_KEY, imgp->ip_strings, strlen(EXECUTABLE_KEY)); + len += strlen(EXECUTABLE_KEY); + imgp->ip_strendp += len; imgp->ip_strspace -= len; - imgp->ip_argv = imgp->ip_strendp; + + if (excpath) { + *excpath = imgp->ip_strings + strlen(EXECUTABLE_KEY); + } } - return(error); + return error; } +/* + * exec_reset_save_path + * + * If we detect a shell script, we need to reset the string area + * state so that the interpreter can be saved onto the stack. + * + * Parameters; struct image_params * image parameter block + * + * Returns: int 0 Success + * + * Implicit returns: + * (imgp->ip_strings) saved path + * (imgp->ip_strspace) space remaining in ip_strings + * (imgp->ip_strendp) start of remaining copy area + * (imgp->ip_argspace) space remaining of NCARGS + * + */ +static int +exec_reset_save_path(struct image_params *imgp) +{ + imgp->ip_strendp = imgp->ip_strings; + imgp->ip_argspace = NCARGS; + imgp->ip_strspace = (NCARGS + PAGE_SIZE); + return 0; +} /* * exec_shell_imgact * - * Image activator for interpreter scripts. If the image begins with the - * characters "#!", then it is an interpreter script. Verify that we are - * not already executing in Classic mode, and that the length of the script - * line indicating the interpreter is not in excess of the maximum allowed - * size. If this is the case, then break out the arguments, if any, which - * are separated by white space, and copy them into the argument save area - * as if they were provided on the command line before all other arguments. - * The line ends when we encounter a comment character ('#') or newline. + * Image activator for interpreter scripts. If the image begins with + * the characters "#!", then it is an interpreter script. Verify the + * length of the script line indicating the interpreter is not in + * excess of the maximum allowed size. If this is the case, then + * break out the arguments, if any, which are separated by white + * space, and copy them into the argument save area as if they were + * provided on the command line before all other arguments. The line + * ends when we encounter a comment character ('#') or newline. * * Parameters; struct image_params * image parameter block * @@ -314,86 +476,137 @@ exec_shell_imgact(struct image_params *imgp) { char *vdata = imgp->ip_vdata; char *ihp; - char *line_endp; + char *line_startp, *line_endp; char *interp; /* * Make sure it's a shell script. If we've already redirected * from an interpreted file once, don't do it again. - * - * Note: We disallow Classic, since the expectation is that we - * may run a Classic interpreter, but not an interpret a Classic - * image. This is consistent with historical behaviour. */ if (vdata[0] != '#' || vdata[1] != '!' || (imgp->ip_flags & IMGPF_INTERPRET) != 0) { - return (-1); + return -1; } + if (imgp->ip_origcputype != 0) { + /* Fat header previously matched, don't allow shell script inside */ + return -1; + } imgp->ip_flags |= IMGPF_INTERPRET; + imgp->ip_interp_sugid_fd = -1; + imgp->ip_interp_buffer[0] = '\0'; - /* Check to see if SUGID scripts are permitted. If they aren't then + /* Check to see if SUGID scripts are permitted. If they aren't then * clear the SUGID bits. * imgp->ip_vattr is known to be valid. - */ - if (sugid_scripts == 0) { - imgp->ip_origvattr->va_mode &= ~(VSUID | VSGID); + */ + if (sugid_scripts == 0) { + imgp->ip_origvattr->va_mode &= ~(VSUID | VSGID); + } + + /* Try to find the first non-whitespace character */ + for (ihp = &vdata[2]; ihp < &vdata[IMG_SHSIZE]; ihp++) { + if (IS_EOL(*ihp)) { + /* Did not find interpreter, "#!\n" */ + return ENOEXEC; + } else if (IS_WHITESPACE(*ihp)) { + /* Whitespace, like "#! /bin/sh\n", keep going. */ + } else { + /* Found start of interpreter */ + break; + } + } + + if (ihp == &vdata[IMG_SHSIZE]) { + /* All whitespace, like "#! " */ + return ENOEXEC; + } + + line_startp = ihp; + + /* Try to find the end of the interpreter+args string */ + for (; ihp < &vdata[IMG_SHSIZE]; ihp++) { + if (IS_EOL(*ihp)) { + /* Got it */ + break; + } else { + /* Still part of interpreter or args */ + } + } + + if (ihp == &vdata[IMG_SHSIZE]) { + /* A long line, like "#! blah blah blah" without end */ + return ENOEXEC; } - /* Find the nominal end of the interpreter line */ - for( ihp = &vdata[2]; *ihp != '\n' && *ihp != '#'; ihp++) { - if (ihp >= &vdata[IMG_SHSIZE]) - return (ENOEXEC); + /* Backtrack until we find the last non-whitespace */ + while (IS_EOL(*ihp) || IS_WHITESPACE(*ihp)) { + ihp--; } - line_endp = ihp; - ihp = &vdata[2]; - /* Skip over leading spaces - until the interpreter name */ - while ( ihp < line_endp && ((*ihp == ' ') || (*ihp == '\t'))) - ihp++; + /* The character after the last non-whitespace is our logical end of line */ + line_endp = ihp + 1; /* - * Find the last non-whitespace character before the end of line or - * the beginning of a comment; this is our new end of line. + * Now we have pointers to the usable part of: + * + * "#! /usr/bin/int first second third \n" + * ^ line_startp ^ line_endp */ - for (;line_endp > ihp && ((*line_endp == ' ') || (*line_endp == '\t')); line_endp--) - continue; - - /* Empty? */ - if (line_endp == ihp) - return (ENOEXEC); /* copy the interpreter name */ - interp = imgp->ip_interp_name; - while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) - *interp++ = *ihp++; + interp = imgp->ip_interp_buffer; + for (ihp = line_startp; (ihp < line_endp) && !IS_WHITESPACE(*ihp); ihp++) { + *interp++ = *ihp; + } *interp = '\0'; - exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_name), - UIO_SYSSPACE32); - - ihp = &vdata[2]; - while (ihp < line_endp) { - /* Skip leading whitespace before each argument */ - while ((*ihp == ' ') || (*ihp == '\t')) - ihp++; + exec_reset_save_path(imgp); + exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_buffer), + UIO_SYSSPACE, NULL); - if (ihp >= line_endp) - break; + /* Copy the entire interpreter + args for later processing into argv[] */ + interp = imgp->ip_interp_buffer; + for (ihp = line_startp; (ihp < line_endp); ihp++) { + *interp++ = *ihp; + } + *interp = '\0'; - /* We have an argument; copy it */ - while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { - *imgp->ip_strendp++ = *ihp++; - imgp->ip_strspace--; +#if !SECURE_KERNEL + /* + * If we have an SUID or SGID script, create a file descriptor + * from the vnode and pass /dev/fd/%d instead of the actual + * path name so that the script does not get opened twice + */ + if (imgp->ip_origvattr->va_mode & (VSUID | VSGID)) { + proc_t p; + struct fileproc *fp; + int fd; + int error; + + p = vfs_context_proc(imgp->ip_vfs_context); + error = falloc(p, &fp, &fd, imgp->ip_vfs_context); + if (error) { + return error; } - *imgp->ip_strendp++ = 0; - imgp->ip_strspace--; - imgp->ip_argc++; + + fp->f_fglob->fg_flag = FREAD; + fp->f_fglob->fg_ops = &vnops; + fp->f_fglob->fg_data = (caddr_t)imgp->ip_vp; + + proc_fdlock(p); + procfdtbl_releasefd(p, fd, NULL); + fp_drop(p, fd, fp, 1); + proc_fdunlock(p); + vnode_ref(imgp->ip_vp); + + imgp->ip_interp_sugid_fd = fd; } +#endif - return (-3); + return -3; } @@ -407,9 +620,19 @@ exec_shell_imgact(struct image_params *imgp) * reloading the first page for the image with a first page from the * offset location indicated by the fat header. * + * Parameters; struct image_params * image parameter block + * + * Returns: -1 not a fat binary (keep looking) + * -2 Success: encapsulated binary: reread + * >0 Failure: error number + * * Important: This image activator is byte order neutral. * - * Note: If we find an encapsulated binary, we make no assertions + * Note: A return value other than -1 indicates subsequent image + * activators should not be given the opportunity to attempt + * to activate the image. + * + * If we find an encapsulated binary, we make no assertions * about its validity; instead, we leave that up to a rescan * for an activator to claim it, and, if it is claimed by one, * that activator is responsible for determining validity. @@ -417,52 +640,166 @@ exec_shell_imgact(struct image_params *imgp) static int exec_fat_imgact(struct image_params *imgp) { - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - kauth_cred_t cred = p->p_ucred; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + kauth_cred_t cred = kauth_cred_proc_ref(p); struct fat_header *fat_header = (struct fat_header *)imgp->ip_vdata; + struct _posix_spawnattr *psa = NULL; struct fat_arch fat_arch; int resid, error; load_return_t lret; + if (imgp->ip_origcputype != 0) { + /* Fat header previously matched, don't allow another fat file inside */ + error = -1; /* not claimed */ + goto bad; + } + /* Make sure it's a fat binary */ - if ((fat_header->magic != FAT_MAGIC) && - (fat_header->magic != FAT_CIGAM)) { - error = -1; + if (OSSwapBigToHostInt32(fat_header->magic) != FAT_MAGIC) { + error = -1; /* not claimed */ + goto bad; + } + + /* imgp->ip_vdata has PAGE_SIZE, zerofilled if the file is smaller */ + lret = fatfile_validate_fatarches((vm_offset_t)fat_header, PAGE_SIZE); + if (lret != LOAD_SUCCESS) { + error = load_return_to_errno(lret); + goto bad; + } + + /* If posix_spawn binprefs exist, respect those prefs. */ + psa = (struct _posix_spawnattr *) imgp->ip_px_sa; + if (psa != NULL && psa->psa_binprefs[0] != 0) { + uint32_t pr = 0; + + /* Check each preference listed against all arches in header */ + for (pr = 0; pr < NBINPREFS; pr++) { + cpu_type_t pref = psa->psa_binprefs[pr]; + if (pref == 0) { + /* No suitable arch in the pref list */ + error = EBADARCH; + goto bad; + } + + if (pref == CPU_TYPE_ANY) { + /* Fall through to regular grading */ + goto regular_grading; + } + + lret = fatfile_getbestarch_for_cputype(pref, + (vm_offset_t)fat_header, + PAGE_SIZE, + &fat_arch); + if (lret == LOAD_SUCCESS) { + goto use_arch; + } + } + + /* Requested binary preference was not honored */ + error = EBADEXEC; goto bad; } +regular_grading: /* Look up our preferred architecture in the fat file. */ - lret = fatfile_getarch_affinity(imgp->ip_vp, - (vm_offset_t)fat_header, - &fat_arch, - (p->p_flag & P_AFFINITY)); + lret = fatfile_getbestarch((vm_offset_t)fat_header, + PAGE_SIZE, + &fat_arch); if (lret != LOAD_SUCCESS) { error = load_return_to_errno(lret); goto bad; } - /* Read the Mach-O header out of it */ +use_arch: + /* Read the Mach-O header out of fat_arch */ error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, - PAGE_SIZE, fat_arch.offset, - UIO_SYSSPACE32, (IO_UNIT|IO_NODELOCKED), - cred, &resid, p); + PAGE_SIZE, fat_arch.offset, + UIO_SYSSPACE, (IO_UNIT | IO_NODELOCKED), + cred, &resid, p); if (error) { goto bad; } - /* Did we read a complete header? */ if (resid) { - error = EBADEXEC; - goto bad; + memset(imgp->ip_vdata + (PAGE_SIZE - resid), 0x0, resid); } /* Success. Indicate we have identified an encapsulated binary */ error = -2; imgp->ip_arch_offset = (user_size_t)fat_arch.offset; imgp->ip_arch_size = (user_size_t)fat_arch.size; + imgp->ip_origcputype = fat_arch.cputype; + imgp->ip_origcpusubtype = fat_arch.cpusubtype; bad: - return (error); + kauth_cred_unref(&cred); + return error; +} + +static int +activate_exec_state(task_t task, proc_t p, thread_t thread, load_result_t *result) +{ + int ret; + + task_set_dyld_info(task, MACH_VM_MIN_ADDRESS, 0); + task_set_64bit(task, result->is_64bit_addr, result->is_64bit_data); + if (result->is_64bit_addr) { + OSBitOrAtomic(P_LP64, &p->p_flag); + } else { + OSBitAndAtomic(~((uint32_t)P_LP64), &p->p_flag); + } + + ret = thread_state_initialize(thread); + if (ret != KERN_SUCCESS) { + return ret; + } + + if (result->threadstate) { + uint32_t *ts = result->threadstate; + uint32_t total_size = result->threadstate_sz; + + while (total_size > 0) { + uint32_t flavor = *ts++; + uint32_t size = *ts++; + + ret = thread_setstatus(thread, flavor, (thread_state_t)ts, size); + if (ret) { + return ret; + } + ts += size; + total_size -= (size + 2) * sizeof(uint32_t); + } + } + + thread_setentrypoint(thread, result->entry_point); + + return KERN_SUCCESS; +} + + +/* + * Set p->p_comm and p->p_name to the name passed to exec + */ +static void +set_proc_name(struct image_params *imgp, proc_t p) +{ + int p_name_len = sizeof(p->p_name) - 1; + + if (imgp->ip_ndp->ni_cnd.cn_namelen > p_name_len) { + imgp->ip_ndp->ni_cnd.cn_namelen = p_name_len; + } + + bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_name, + (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen); + p->p_name[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0'; + + if (imgp->ip_ndp->ni_cnd.cn_namelen > MAXCOMLEN) { + imgp->ip_ndp->ni_cnd.cn_namelen = MAXCOMLEN; + } + + bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_comm, + (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen); + p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0'; } /* @@ -470,184 +807,329 @@ bad: * * Image activator for mach-o 1.0 binaries. * + * Parameters; struct image_params * image parameter block + * + * Returns: -1 not a fat binary (keep looking) + * -2 Success: encapsulated binary: reread + * >0 Failure: error number + * EBADARCH Mach-o binary, but with an unrecognized + * architecture + * ENOMEM No memory for child process after - + * can only happen after vfork() + * * Important: This image activator is NOT byte order neutral. + * + * Note: A return value other than -1 indicates subsequent image + * activators should not be given the opportunity to attempt + * to activate the image. + * + * TODO: More gracefully handle failures after vfork */ static int exec_mach_imgact(struct image_params *imgp) { struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata; - kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - int error = 0; - int vfexec = 0; - task_t task; - task_t new_task; - thread_t thread; - struct uthread *uthread; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + int error = 0; + task_t task; + task_t new_task = NULL; /* protected by vfexec */ + thread_t thread; + struct uthread *uthread; vm_map_t old_map = VM_MAP_NULL; - vm_map_t map; - boolean_t clean_regions = FALSE; - shared_region_mapping_t initial_region = NULL; - load_return_t lret; - load_result_t load_result; - + vm_map_t map = VM_MAP_NULL; + load_return_t lret; + load_result_t load_result = {}; + struct _posix_spawnattr *psa = NULL; + int spawn = (imgp->ip_flags & IMGPF_SPAWN); + int vfexec = (imgp->ip_flags & IMGPF_VFORK_EXEC); + int exec = (imgp->ip_flags & IMGPF_EXEC); + os_reason_t exec_failure_reason = OS_REASON_NULL; + /* * make sure it's a Mach-O 1.0 or Mach-O 2.0 binary; the difference * is a reserved field on the end, so for the most part, we can - * treat them as if they were identical. + * treat them as if they were identical. Reverse-endian Mach-O + * binaries are recognized but not compatible. */ + if ((mach_header->magic == MH_CIGAM) || + (mach_header->magic == MH_CIGAM_64)) { + error = EBADARCH; + goto bad; + } + if ((mach_header->magic != MH_MAGIC) && (mach_header->magic != MH_MAGIC_64)) { - error = -1; + error = -1; + goto bad; + } + + if (mach_header->filetype != MH_EXECUTE) { + error = -1; goto bad; } + if (imgp->ip_origcputype != 0) { + /* Fat header previously had an idea about this thin file */ + if (imgp->ip_origcputype != mach_header->cputype || + imgp->ip_origcpusubtype != mach_header->cpusubtype) { + error = EBADARCH; + goto bad; + } + } else { + imgp->ip_origcputype = mach_header->cputype; + imgp->ip_origcpusubtype = mach_header->cpusubtype; + } + task = current_task(); thread = current_thread(); uthread = get_bsdthread_info(thread); - if (uthread->uu_flag & UT_VFORK) - vfexec = 1; /* Mark in exec */ + if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64) { + imgp->ip_flags |= IMGPF_IS_64BIT_ADDR | IMGPF_IS_64BIT_DATA; + } + + /* If posix_spawn binprefs exist, respect those prefs. */ + psa = (struct _posix_spawnattr *) imgp->ip_px_sa; + if (psa != NULL && psa->psa_binprefs[0] != 0) { + int pr = 0; + for (pr = 0; pr < NBINPREFS; pr++) { + cpu_type_t pref = psa->psa_binprefs[pr]; + if (pref == 0) { + /* No suitable arch in the pref list */ + error = EBADARCH; + goto bad; + } - if ((mach_header->cputype & CPU_ARCH_ABI64) == CPU_ARCH_ABI64) - imgp->ip_flags |= IMGPF_IS_64BIT; + if (pref == CPU_TYPE_ANY) { + /* Jump to regular grading */ + goto grade; + } - if (!grade_binary(mach_header->cputype, mach_header->cpusubtype)) { + if (pref == imgp->ip_origcputype) { + /* We have a match! */ + goto grade; + } + } + error = EBADARCH; + goto bad; + } +grade: + if (!grade_binary(imgp->ip_origcputype, imgp->ip_origcpusubtype & ~CPU_SUBTYPE_MASK)) { error = EBADARCH; goto bad; } + + /* Copy in arguments/environment from the old process */ + error = exec_extract_strings(imgp); + if (error) { + goto bad; + } + + AUDIT_ARG(argv, imgp->ip_startargv, imgp->ip_argc, + imgp->ip_endargv - imgp->ip_startargv); + AUDIT_ARG(envv, imgp->ip_endargv, imgp->ip_envc, + imgp->ip_endenvv - imgp->ip_endargv); + /* - * Copy in arguments/environment from the old process, if the - * vector is non-NULL (i.e. exec is not being called from - * load_init_program(), as a special case, at system startup). + * We are being called to activate an image subsequent to a vfork() + * operation; in this case, we know that our task, thread, and + * uthread are actually those of our parent, and our proc, which we + * obtained indirectly from the image_params vfs_context_t, is the + * new child process. */ - if (imgp->ip_user_argv != 0LL) { - error = exec_extract_strings(imgp); - if (error) + if (vfexec) { + imgp->ip_new_thread = fork_create_child(task, + NULL, + p, + FALSE, + (imgp->ip_flags & IMGPF_IS_64BIT_ADDR), + (imgp->ip_flags & IMGPF_IS_64BIT_DATA), + FALSE); + /* task and thread ref returned, will be released in __mac_execve */ + if (imgp->ip_new_thread == NULL) { + error = ENOMEM; goto bad; + } } + + /* reset local idea of thread, uthread, task */ + thread = imgp->ip_new_thread; + uthread = get_bsdthread_info(thread); + task = new_task = get_threadtask(thread); + /* - * Hack for binary compatability; put three NULs on the end of the - * string area, and round it up to the next word boundary. This - * ensures padding with NULs to the boundary. + * Load the Mach-O file. + * + * NOTE: An error after this point indicates we have potentially + * destroyed or overwritten some process state while attempting an + * execve() following a vfork(), which is an unrecoverable condition. + * We send the new process an immediate SIGKILL to avoid it executing + * any instructions in the mutated address space. For true spawns, + * this is not the case, and "too late" is still not too late to + * return an error code to the parent process. + */ + + /* + * Actually load the image file we previously decided to load. */ - imgp->ip_strendp[0] = 0; - imgp->ip_strendp[1] = 0; - imgp->ip_strendp[2] = 0; - imgp->ip_strendp += (((imgp->ip_strendp - imgp->ip_strings) + NBPW-1) & ~(NBPW-1)); + lret = load_machfile(imgp, mach_header, thread, &map, &load_result); + if (lret != LOAD_SUCCESS) { + error = load_return_to_errno(lret); + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO, 0, 0); + if (lret == LOAD_BADMACHO_UPX) { + /* set anything that might be useful in the crash report */ + set_proc_name(imgp, p); + + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_UPX); + exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT; + exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE; + } else if (lret == LOAD_BADARCH_X86) { + /* set anything that might be useful in the crash report */ + set_proc_name(imgp, p); + + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_NO32EXEC); + exec_failure_reason->osr_flags |= OS_REASON_FLAG_GENERATE_CRASH_REPORT; + exec_failure_reason->osr_flags |= OS_REASON_FLAG_CONSISTENT_FAILURE; + } else { + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_BAD_MACHO); + } - if (vfexec) { - kern_return_t result; - - result = task_create_internal(task, FALSE, &new_task); - if (result != KERN_SUCCESS) - printf("execve: task_create failed. Code: 0x%x\n", result); - p->task = new_task; - set_bsdtask_info(new_task, p); - if (p->p_nice != 0) - resetpriority(p); - map = get_task_map(new_task); - result = thread_create(new_task, &imgp->ip_vfork_thread); - if (result != KERN_SUCCESS) - printf("execve: thread_create failed. Code: 0x%x\n", result); - /* reset local idea of task, thread, uthread */ - task = new_task; - thread = imgp->ip_vfork_thread; - uthread = get_bsdthread_info(thread); - } else { - map = VM_MAP_NULL; + goto badtoolate; } + proc_lock(p); + p->p_cputype = imgp->ip_origcputype; + p->p_cpusubtype = imgp->ip_origcpusubtype; + proc_unlock(p); + + vm_map_set_user_wire_limit(map, p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur); + /* - * We set these flags here; this is OK, since if we fail after - * this point, we have already destroyed the parent process anyway. + * Set code-signing flags if this binary is signed, or if parent has + * requested them on exec. */ - if (imgp->ip_flags & IMGPF_IS_64BIT) { - task_set_64bit(task, TRUE); - p->p_flag |= P_LP64; + if (load_result.csflags & CS_VALID) { + imgp->ip_csflags |= load_result.csflags & + (CS_VALID | CS_SIGNED | CS_DEV_CODE | + CS_HARD | CS_KILL | CS_RESTRICT | CS_ENFORCEMENT | CS_REQUIRE_LV | + CS_FORCED_LV | CS_ENTITLEMENTS_VALIDATED | CS_DYLD_PLATFORM | CS_RUNTIME | + CS_ENTITLEMENT_FLAGS | + CS_EXEC_SET_HARD | CS_EXEC_SET_KILL | CS_EXEC_SET_ENFORCEMENT); } else { - task_set_64bit(task, FALSE); - p->p_flag &= ~P_LP64; + imgp->ip_csflags &= ~CS_VALID; } - /* - * Load the Mach-O file. - */ -/* LP64 - remove following "if" statement after osfmk/vm/task_working_set.c */ -if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) - if(imgp->ip_tws_cache_name) { - tws_handle_startup_file(task, kauth_cred_getuid(cred), - imgp->ip_tws_cache_name, imgp->ip_vp, &clean_regions); + if (p->p_csflags & CS_EXEC_SET_HARD) { + imgp->ip_csflags |= CS_HARD; + } + if (p->p_csflags & CS_EXEC_SET_KILL) { + imgp->ip_csflags |= CS_KILL; + } + if (p->p_csflags & CS_EXEC_SET_ENFORCEMENT) { + imgp->ip_csflags |= CS_ENFORCEMENT; + } + if (p->p_csflags & CS_EXEC_INHERIT_SIP) { + if (p->p_csflags & CS_INSTALLER) { + imgp->ip_csflags |= CS_INSTALLER; + } + if (p->p_csflags & CS_DATAVAULT_CONTROLLER) { + imgp->ip_csflags |= CS_DATAVAULT_CONTROLLER; + } + if (p->p_csflags & CS_NVRAM_UNRESTRICTED) { + imgp->ip_csflags |= CS_NVRAM_UNRESTRICTED; + } } - vm_get_shared_region(task, &initial_region); - - /* - * NOTE: An error after this point indicates we have potentially - * destroyed or overwrote some process state while attempting an - * execve() following a vfork(), which is an unrecoverable condition. + * Set up the system reserved areas in the new address space. */ + int cpu_subtype; + cpu_subtype = 0; /* all cpu_subtypes use the same shared region */ + vm_map_exec(map, task, load_result.is_64bit_addr, (void *)p->p_fd->fd_rdir, cpu_type(), cpu_subtype); /* - * We reset the task to 64-bit (or not) here. It may have picked up - * a new map, and we need that to reflect its true 64-bit nature. + * Close file descriptors which specify close-on-exec. */ - task_set_64bit(task, - ((imgp->ip_flags & IMGPF_IS_64BIT) == IMGPF_IS_64BIT)); + fdexec(p, psa != NULL ? psa->psa_flags : 0, exec); /* - * Actually load the image file we previously decided to load. + * deal with set[ug]id. */ - lret = load_machfile(imgp, mach_header, thread, map, clean_regions, &load_result); + error = exec_handle_sugid(imgp); + if (error) { + vm_map_deallocate(map); - if (lret != LOAD_SUCCESS) { - error = load_return_to_errno(lret); + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_SUGID_FAILURE, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SUGID_FAILURE); goto badtoolate; } - /* load_machfile() maps the vnode */ - (void)ubc_map(imgp->ip_vp, PROT_EXEC); - - /* - * Close file descriptors - * which specify close-on-exec. + /* + * Commit to new map. + * + * Swap the new map for the old for target task, which consumes + * our new map reference but each leaves us responsible for the + * old_map reference. That lets us get off the pmap associated + * with it, and then we can release it. + * + * The map needs to be set on the target task which is different + * than current task, thus swap_task_map is used instead of + * vm_map_switch. */ - fdexec(p); + old_map = swap_task_map(task, thread, map); + vm_map_deallocate(old_map); + old_map = NULL; + + lret = activate_exec_state(task, p, thread, &load_result); + if (lret != KERN_SUCCESS) { + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_ACTV_THREADSTATE, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_ACTV_THREADSTATE); + goto badtoolate; + } /* - * deal with set[ug]id. + * deal with voucher on exec-calling thread. */ - error = exec_handle_sugid(imgp); - - KNOTE(&p->p_klist, NOTE_EXEC); + if (imgp->ip_new_thread == NULL) { + thread_set_mach_voucher(current_thread(), IPC_VOUCHER_NULL); + } - if (!vfexec && (p->p_flag & P_TRACED)) + /* Make sure we won't interrupt ourself signalling a partial process */ + if (!vfexec && !spawn && (p->p_lflag & P_LTRACED)) { psignal(p, SIGTRAP); - - if (error) { - goto badtoolate; } - vnode_put(imgp->ip_vp); - imgp->ip_vp = NULL; - + if (load_result.unixproc && - create_unix_stack(get_task_map(task), - load_result.user_stack, load_result.customstack, p)) { + create_unix_stack(get_task_map(task), + &load_result, + p) != KERN_SUCCESS) { error = load_return_to_errno(LOAD_NOSPACE); + + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_STACK_ALLOC, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_STACK_ALLOC); goto badtoolate; } - if (vfexec) { - uthread->uu_ar0 = (void *)get_user_regs(thread); - old_map = vm_map_switch(get_task_map(task)); + error = exec_add_apple_strings(imgp, &load_result); + if (error) { + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_APPLE_STRING_INIT, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_APPLE_STRING_INIT); + goto badtoolate; } + /* Switch to target task's map to copy out strings */ + old_map = vm_map_switch(get_task_map(task)); + if (load_result.unixproc) { - user_addr_t ap; + user_addr_t ap; /* * Copy the strings area out into the new process address @@ -656,32 +1138,41 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) ap = p->user_stack; error = exec_copyout_strings(imgp, &ap); if (error) { - if (vfexec) - vm_map_switch(old_map); + vm_map_switch(old_map); + + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_STRINGS, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_STRINGS); goto badtoolate; } /* Set the stack */ thread_setuserstack(thread, ap); } - + if (load_result.dynlinker) { - uint64_t ap; + uint64_t ap; + int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4; /* Adjust the stack */ - if (imgp->ip_flags & IMGPF_IS_64BIT) { - ap = thread_adjuserstack(thread, -8); - (void)copyoutptr(load_result.mach_header, ap, 8); - } else { - ap = thread_adjuserstack(thread, -4); - (void)suword(ap, load_result.mach_header); + ap = thread_adjuserstack(thread, -new_ptr_size); + error = copyoutptr(load_result.mach_header, ap, new_ptr_size); + + if (error) { + vm_map_switch(old_map); + + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_DYNLINKER, 0, 0); + exec_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_COPYOUT_DYNLINKER); + goto badtoolate; } + task_set_dyld_info(task, load_result.all_image_info_addr, + load_result.all_image_info_size); } - if (vfexec) { - vm_map_switch(old_map); - } - /* Set the entry point */ - thread_setentrypoint(thread, load_result.entry_point); + /* Avoid immediate VM faults back into kernel */ + exec_prefault_data(p, imgp, &load_result); + + vm_map_switch(old_map); /* Stop profiling */ stopprofclock(p); @@ -697,82 +1188,187 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) */ _aio_exec( p ); +#if SYSV_SHM /* FIXME: Till vmspace inherit is fixed: */ - if (!vfexec && p->vm_shm) + if (!vfexec && p->vm_shm) { shmexec(p); + } +#endif +#if SYSV_SEM /* Clean up the semaphores */ semexit(p); +#endif /* * Remember file name for accounting. */ p->p_acflag &= ~AFORK; - /* If the translated name isn't NULL, then we want to use - * that translated name as the name we show as the "real" name. - * Otherwise, use the name passed into exec. + + set_proc_name(imgp, p); + +#if CONFIG_SECLUDED_MEMORY + if (secluded_for_apps && + load_result.platform_binary) { + if (strncmp(p->p_name, + "Camera", + sizeof(p->p_name)) == 0) { + task_set_could_use_secluded_mem(task, TRUE); + } else { + task_set_could_use_secluded_mem(task, FALSE); + } + if (strncmp(p->p_name, + "mediaserverd", + sizeof(p->p_name)) == 0) { + task_set_could_also_use_secluded_mem(task, TRUE); + } + } +#endif /* CONFIG_SECLUDED_MEMORY */ + +#if __arm64__ + if (load_result.legacy_footprint) { +#if DEVELOPMENT || DEBUG + printf("%s: %d[%s] legacy footprint (mach-o)\n", + __FUNCTION__, p->p_pid, p->p_name); +#endif /* DEVELOPMENT || DEBUG */ + task_set_legacy_footprint(task, TRUE); + } +#endif /* __arm64__ */ + + pal_dbg_set_task_name(task); + + /* + * The load result will have already been munged by AMFI to include the + * platform binary flag if boot-args dictated it (AMFI will mark anything + * that doesn't go through the upcall path as a platform binary if its + * enforcement is disabled). */ - if (0 != imgp->ip_p_comm[0]) { - bcopy((caddr_t)imgp->ip_p_comm, (caddr_t)p->p_comm, - sizeof(p->p_comm)); + if (load_result.platform_binary) { + if (cs_debug) { + printf("setting platform binary on task: pid = %d\n", p->p_pid); + } + + /* + * We must use 'task' here because the proc's task has not yet been + * switched to the new one. + */ + task_set_platform_binary(task, TRUE); } else { - if (imgp->ip_ndp->ni_cnd.cn_namelen > MAXCOMLEN) - imgp->ip_ndp->ni_cnd.cn_namelen = MAXCOMLEN; - bcopy((caddr_t)imgp->ip_ndp->ni_cnd.cn_nameptr, (caddr_t)p->p_comm, - (unsigned)imgp->ip_ndp->ni_cnd.cn_namelen); - p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0'; + if (cs_debug) { + printf("clearing platform binary on task: pid = %d\n", p->p_pid); + } + + task_set_platform_binary(task, FALSE); } - { - /* This is for kdebug */ - long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4; +#if DEVELOPMENT || DEBUG + /* + * Update the pid an proc name for importance base if any + */ + task_importance_update_owner_info(task); +#endif - /* Collect the pathname for tracing */ - kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4); + memcpy(&p->p_uuid[0], &load_result.uuid[0], sizeof(p->p_uuid)); +#if CONFIG_DTRACE + dtrace_proc_exec(p); +#endif + if (kdebug_enable) { + long args[4] = {}; + + uintptr_t fsid = 0, fileid = 0; + if (imgp->ip_vattr) { + uint64_t fsid64 = vnode_get_va_fsid(imgp->ip_vattr); + fsid = fsid64; + fileid = imgp->ip_vattr->va_fileid; + // check for (unexpected) overflow and trace zero in that case + if (fsid != fsid64 || fileid != imgp->ip_vattr->va_fileid) { + fsid = fileid = 0; + } + } + KERNEL_DEBUG_CONSTANT_IST1(TRACE_DATA_EXEC, p->p_pid, fsid, fileid, 0, + (uintptr_t)thread_tid(thread)); - if (vfexec) - { - KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE, - p->p_pid ,0,0,0, (unsigned int)thread); - KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE, - dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (unsigned int)thread); - } - else - { - KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE, - p->p_pid ,0,0,0,0); - KERNEL_DEBUG_CONSTANT((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE, - dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, 0); - } + /* + * Collect the pathname for tracing + */ + kdbg_trace_string(p, &args[0], &args[1], &args[2], &args[3]); + KERNEL_DEBUG_CONSTANT_IST1(TRACE_STRING_EXEC, args[0], args[1], + args[2], args[3], (uintptr_t)thread_tid(thread)); } - p->p_flag &= ~P_CLASSIC; + /* + * If posix_spawned with the START_SUSPENDED flag, stop the + * process before it runs. + */ + if (imgp->ip_px_sa != NULL) { + psa = (struct _posix_spawnattr *) imgp->ip_px_sa; + if (psa->psa_flags & POSIX_SPAWN_START_SUSPENDED) { + proc_lock(p); + p->p_stat = SSTOP; + proc_unlock(p); + (void) task_suspend_internal(task); + } + } /* * mark as execed, wakeup the process that vforked (if any) and tell - * it that it now has it's own resources back + * it that it now has its own resources back */ - p->p_flag |= P_EXEC; - if (p->p_pptr && (p->p_flag & P_PPWAIT)) { - p->p_flag &= ~P_PPWAIT; + OSBitOrAtomic(P_EXEC, &p->p_flag); + proc_resetregister(p); + if (p->p_pptr && (p->p_lflag & P_LPPWAIT)) { + proc_lock(p); + p->p_lflag &= ~P_LPPWAIT; + proc_unlock(p); wakeup((caddr_t)p->p_pptr); } - if (vfexec && (p->p_flag & P_TRACED)) { + /* + * Pay for our earlier safety; deliver the delayed signals from + * the incomplete vfexec process now that it's complete. + */ + if (vfexec && (p->p_lflag & P_LTRACED)) { psignal_vfork(p, new_task, thread, SIGTRAP); } + goto done; + badtoolate: - if (vfexec) { - task_deallocate(new_task); - thread_deallocate(thread); - if (error) - error = 0; + /* Don't allow child process to execute any instructions */ + if (!spawn) { + if (vfexec) { + assert(exec_failure_reason != OS_REASON_NULL); + psignal_vfork_with_reason(p, new_task, thread, SIGKILL, exec_failure_reason); + exec_failure_reason = OS_REASON_NULL; + } else { + assert(exec_failure_reason != OS_REASON_NULL); + psignal_with_reason(p, SIGKILL, exec_failure_reason); + exec_failure_reason = OS_REASON_NULL; + + if (exec) { + /* Terminate the exec copy task */ + task_terminate_internal(task); + } + } + + /* We can't stop this system call at this point, so just pretend we succeeded */ + error = 0; + } else { + os_reason_free(exec_failure_reason); + exec_failure_reason = OS_REASON_NULL; + } + +done: + if (load_result.threadstate) { + kfree(load_result.threadstate, load_result.threadstate_sz); + load_result.threadstate = NULL; } bad: - return(error); + /* If we hit this, we likely would have leaked an exit reason */ + assert(exec_failure_reason == OS_REASON_NULL); + return error; } @@ -789,953 +1385,4663 @@ struct execsw { int (*ex_imgact)(struct image_params *); const char *ex_name; } execsw[] = { - { exec_mach_imgact, "Mach-o Binary" }, - { exec_fat_imgact, "Fat Binary" }, - { exec_shell_imgact, "Interpreter Script" }, + { exec_mach_imgact, "Mach-o Binary" }, + { exec_fat_imgact, "Fat Binary" }, + { exec_shell_imgact, "Interpreter Script" }, { NULL, NULL} }; /* - * TODO: Dynamic linker header address on stack is copied via suword() + * exec_activate_image + * + * Description: Iterate through the available image activators, and activate + * the image associated with the imgp structure. We start with + * the activator for Mach-o binaries followed by that for Fat binaries + * for Interpreter scripts. + * + * Parameters: struct image_params * Image parameter block + * + * Returns: 0 Success + * EBADEXEC The executable is corrupt/unknown + * execargs_alloc:EINVAL Invalid argument + * execargs_alloc:EACCES Permission denied + * execargs_alloc:EINTR Interrupted function + * execargs_alloc:ENOMEM Not enough space + * exec_save_path:EFAULT Bad address + * exec_save_path:ENAMETOOLONG Filename too long + * exec_check_permissions:EACCES Permission denied + * exec_check_permissions:ENOEXEC Executable file format error + * exec_check_permissions:ETXTBSY Text file busy [misuse of error code] + * exec_check_permissions:??? + * namei:??? + * vn_rdwr:??? [anything vn_rdwr can return] + * :??? [anything an imgact can return] + * EDEADLK Process is being terminated */ -/* ARGSUSED */ -int -execve(struct proc *p, struct execve_args *uap, register_t *retval) +static int +exec_activate_image(struct image_params *imgp) { - kauth_cred_t cred = p->p_ucred; - struct image_params image_params, *imgp; - struct vnode_attr va; - struct vnode_attr origva; - struct nameidata nd; - struct uthread *uthread; + struct nameidata *ndp = NULL; + const char *excpath; + int error; + int resid; + int once = 1; /* save SGUID-ness for interpreted files */ int i; - int resid, error; - task_t task; - int numthreads; - int vfexec=0; - int once = 1; /* save SGUID-ness for interpreted files */ - char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for Classic */ - int is_64 = IS_64BIT_PROCESS(p); - int seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); - struct vfs_context context; - - context.vc_proc = p; - context.vc_ucred = p->p_ucred; /* XXX must NOT be kauth_cred_get() */ - + int itercount = 0; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); - imgp = &image_params; - - /* Initialize the common data in the image_params structure */ - bzero(imgp, sizeof(*imgp)); - imgp->ip_user_fname = uap->fname; - imgp->ip_user_argv = uap->argp; - imgp->ip_user_envv = uap->envp; - imgp->ip_vattr = &va; - imgp->ip_origvattr = &origva; - imgp->ip_vfs_context = &context; - imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT : IMGPF_NONE); - imgp->ip_tws_cache_name = NULL; - imgp->ip_p_comm = alt_p_comm; /* for Classic */ + error = execargs_alloc(imgp); + if (error) { + goto bad_notrans; + } - /* - * XXXAUDIT: Currently, we only audit the pathname of the binary. - * There may also be poor interaction with dyld. - */ + error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg, &excpath); + if (error) { + goto bad_notrans; + } - task = current_task(); - uthread = get_bsdthread_info(current_thread()); + /* Use excpath, which contains the copyin-ed exec path */ + DTRACE_PROC1(exec, uintptr_t, excpath); - if (uthread->uu_flag & UT_VFORK) { - vfexec = 1; /* Mark in exec */ - } else { - if (task != kernel_task) { - numthreads = get_task_numacts(task); - if (numthreads <= 0 ) - return(EINVAL); - if (numthreads > 1) { - return(ENOTSUP); - } - } + MALLOC(ndp, struct nameidata *, sizeof(*ndp), M_TEMP, M_WAITOK | M_ZERO); + if (ndp == NULL) { + error = ENOMEM; + goto bad_notrans; } - error = execargs_alloc(imgp); - if (error) - return(error); - - /* - * XXXAUDIT: Note: the double copyin introduces an audit - * race. To correct this race, we must use a single - * copyin(), e.g. by passing a flag to namei to indicate an - * external path buffer is being used. - */ - error = exec_save_path(imgp, uap->fname, seg); + NDINIT(ndp, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1, + UIO_SYSSPACE, CAST_USER_ADDR_T(excpath), imgp->ip_vfs_context); + +again: + error = namei(ndp); if (error) { - execargs_free(imgp); - return(error); + goto bad_notrans; } + imgp->ip_ndp = ndp; /* successful namei(); call nameidone() later */ + imgp->ip_vp = ndp->ni_vp; /* if set, need to vnode_put() at some point */ /* - * No app profiles under chroot + * Before we start the transition from binary A to binary B, make + * sure another thread hasn't started exiting the process. We grab + * the proc lock to check p_lflag initially, and the transition + * mechanism ensures that the value doesn't change after we release + * the lock. */ - if((p->p_fd->fd_rdir == NULLVP) && (app_profile != 0)) { - - /* grab the name of the file out of its path */ - /* we will need this for lookup within the */ - /* name file */ - /* Scan backwards for the first '/' or start of string */ - imgp->ip_tws_cache_name = imgp->ip_strendp; - while (imgp->ip_tws_cache_name[0] != '/') { - if(imgp->ip_tws_cache_name == imgp->ip_strings) { - imgp->ip_tws_cache_name--; - break; - } - imgp->ip_tws_cache_name--; - } - imgp->ip_tws_cache_name++; + proc_lock(p); + if (p->p_lflag & P_LEXIT) { + error = EDEADLK; + proc_unlock(p); + goto bad_notrans; + } + error = proc_transstart(p, 1, 0); + proc_unlock(p); + if (error) { + goto bad_notrans; } - NDINIT(&nd, LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1, - seg, uap->fname, imgp->ip_vfs_context); - -again: - error = namei(&nd); - if (error) - goto bad; - imgp->ip_ndp = &nd; /* successful namei(); call nameidone() later */ - imgp->ip_vp = nd.ni_vp; /* if set, need to vnode_put() at some point */ error = exec_check_permissions(imgp); - if (error) + if (error) { goto bad; + } /* Copy; avoid invocation of an interpreter overwriting the original */ if (once) { once = 0; - origva = va; + *imgp->ip_origvattr = *imgp->ip_vattr; } error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0, - UIO_SYSSPACE32, IO_NODELOCKED, cred, &resid, p); - if (error) + UIO_SYSSPACE, IO_NODELOCKED, + vfs_context_ucred(imgp->ip_vfs_context), + &resid, vfs_context_proc(imgp->ip_vfs_context)); + if (error) { goto bad; - + } + + if (resid) { + memset(imgp->ip_vdata + (PAGE_SIZE - resid), 0x0, resid); + } + encapsulated_binary: + /* Limit the number of iterations we will attempt on each binary */ + if (++itercount > EAI_ITERLIMIT) { + error = EBADEXEC; + goto bad; + } error = -1; - for(i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) { - + for (i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) { error = (*execsw[i].ex_imgact)(imgp); switch (error) { /* case -1: not claimed: continue */ - case -2: /* Encapsulated binary */ + case -2: /* Encapsulated binary, imgp->ip_XXX set for next iteration */ goto encapsulated_binary; - case -3: /* Interpreter */ + case -3: /* Interpreter */ +#if CONFIG_MACF + /* + * Copy the script label for later use. Note that + * the label can be different when the script is + * actually read by the interpreter. + */ + if (imgp->ip_scriptlabelp) { + mac_vnode_label_free(imgp->ip_scriptlabelp); + } + imgp->ip_scriptlabelp = mac_vnode_label_alloc(); + if (imgp->ip_scriptlabelp == NULL) { + error = ENOMEM; + break; + } + mac_vnode_label_copy(imgp->ip_vp->v_label, + imgp->ip_scriptlabelp); + + /* + * Take a ref of the script vnode for later use. + */ + if (imgp->ip_scriptvp) { + vnode_put(imgp->ip_scriptvp); + } + if (vnode_getwithref(imgp->ip_vp) == 0) { + imgp->ip_scriptvp = imgp->ip_vp; + } +#endif + + nameidone(ndp); + vnode_put(imgp->ip_vp); - imgp->ip_vp = NULL; /* already put */ - nd.ni_cnd.cn_nameiop = LOOKUP; - nd.ni_cnd.cn_flags = (nd.ni_cnd.cn_flags & HASBUF) | - (FOLLOW | LOCKLEAF); + imgp->ip_vp = NULL; /* already put */ + imgp->ip_ndp = NULL; /* already nameidone */ + /* Use excpath, which exec_shell_imgact reset to the interpreter */ + NDINIT(ndp, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF, + UIO_SYSSPACE, CAST_USER_ADDR_T(excpath), imgp->ip_vfs_context); - nd.ni_segflg = UIO_SYSSPACE32; - nd.ni_dirp = CAST_USER_ADDR_T(imgp->ip_interp_name); + proc_transend(p, 0); goto again; default: break; } } - - /* call out to allow 3rd party notification of exec. - * Ignore result of kauth_authorize_fileop call. - */ - if (error == 0 && kauth_authorize_fileop_has_listeners()) { - kauth_authorize_fileop(vfs_context_ucred(&context), KAUTH_FILEOP_EXEC, - (uintptr_t)nd.ni_vp, 0); - } - - /* Image not claimed by any activator? */ - if (error == -1) - error = ENOEXEC; + if (error == 0) { + if (imgp->ip_flags & IMGPF_INTERPRET && ndp->ni_vp) { + AUDIT_ARG(vnpath, ndp->ni_vp, ARG_VNODE2); + } + + /* + * Call out to allow 3rd party notification of exec. + * Ignore result of kauth_authorize_fileop call. + */ + if (kauth_authorize_fileop_has_listeners()) { + kauth_authorize_fileop(vfs_context_ucred(imgp->ip_vfs_context), + KAUTH_FILEOP_EXEC, + (uintptr_t)ndp->ni_vp, 0); + } + } bad: - if (imgp->ip_ndp) - nameidone(imgp->ip_ndp); - if (imgp->ip_vp) - vnode_put(imgp->ip_vp); - if (imgp->ip_strings) + proc_transend(p, 0); + +bad_notrans: + if (imgp->ip_strings) { execargs_free(imgp); - if (!error && vfexec) { - vfork_return(current_thread(), p->p_pptr, p, retval); - (void)thread_resume(imgp->ip_vfork_thread); - return(0); } - return(error); + if (imgp->ip_ndp) { + nameidone(imgp->ip_ndp); + } + if (ndp) { + FREE(ndp, M_TEMP); + } + + return error; } -static int -copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size) +/* + * exec_handle_spawnattr_policy + * + * Description: Decode and apply the posix_spawn apptype, qos clamp, and watchport ports to the task. + * + * Parameters: proc_t p process to apply attributes to + * int psa_apptype posix spawn attribute apptype + * + * Returns: 0 Success + */ +static errno_t +exec_handle_spawnattr_policy(proc_t p, int psa_apptype, uint64_t psa_qos_clamp, uint64_t psa_darwin_role, + ipc_port_t * portwatch_ports, int portwatch_count) { - int error; + int apptype = TASK_APPTYPE_NONE; + int qos_clamp = THREAD_QOS_UNSPECIFIED; + int role = TASK_UNSPECIFIED; - if (ptr_size == 4) { - /* 64 bit value containing 32 bit address */ - unsigned int i; + if ((psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK) != 0) { + int proctype = psa_apptype & POSIX_SPAWN_PROC_TYPE_MASK; - error = copyin(froma, &i, 4); - *toptr = CAST_USER_ADDR_T(i); /* SAFE */ - } else { - error = copyin(froma, toptr, 8); + switch (proctype) { + case POSIX_SPAWN_PROC_TYPE_DAEMON_INTERACTIVE: + apptype = TASK_APPTYPE_DAEMON_INTERACTIVE; + break; + case POSIX_SPAWN_PROC_TYPE_DAEMON_STANDARD: + apptype = TASK_APPTYPE_DAEMON_STANDARD; + break; + case POSIX_SPAWN_PROC_TYPE_DAEMON_ADAPTIVE: + apptype = TASK_APPTYPE_DAEMON_ADAPTIVE; + break; + case POSIX_SPAWN_PROC_TYPE_DAEMON_BACKGROUND: + apptype = TASK_APPTYPE_DAEMON_BACKGROUND; + break; + case POSIX_SPAWN_PROC_TYPE_APP_DEFAULT: + apptype = TASK_APPTYPE_APP_DEFAULT; + break; +#if !CONFIG_EMBEDDED + case POSIX_SPAWN_PROC_TYPE_APP_TAL: + apptype = TASK_APPTYPE_APP_TAL; + break; +#endif /* !CONFIG_EMBEDDED */ + default: + apptype = TASK_APPTYPE_NONE; + /* TODO: Should an invalid value here fail the spawn? */ + break; + } } - return (error); -} - -static int -copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size) -{ - int error; + if (psa_qos_clamp != POSIX_SPAWN_PROC_CLAMP_NONE) { + switch (psa_qos_clamp) { + case POSIX_SPAWN_PROC_CLAMP_UTILITY: + qos_clamp = THREAD_QOS_UTILITY; + break; + case POSIX_SPAWN_PROC_CLAMP_BACKGROUND: + qos_clamp = THREAD_QOS_BACKGROUND; + break; + case POSIX_SPAWN_PROC_CLAMP_MAINTENANCE: + qos_clamp = THREAD_QOS_MAINTENANCE; + break; + default: + qos_clamp = THREAD_QOS_UNSPECIFIED; + /* TODO: Should an invalid value here fail the spawn? */ + break; + } + } - if (ptr_size == 4) { - /* 64 bit value containing 32 bit address */ - unsigned int i = CAST_DOWN(unsigned int,ua); /* SAFE */ + if (psa_darwin_role != PRIO_DARWIN_ROLE_DEFAULT) { + proc_darwin_role_to_task_role(psa_darwin_role, &role); + } - error = copyout(&i, ptr, 4); - } else { - error = copyout(&ua, ptr, 8); + if (apptype != TASK_APPTYPE_NONE || + qos_clamp != THREAD_QOS_UNSPECIFIED || + role != TASK_UNSPECIFIED) { + proc_set_task_spawnpolicy(p->task, apptype, qos_clamp, role, + portwatch_ports, portwatch_count); } - return (error); + + return 0; } /* - * exec_copyout_strings + * exec_handle_port_actions * - * Copy out the strings segment to user space. The strings segment is put - * on a preinitialized stack frame. + * Description: Go through the _posix_port_actions_t contents, + * calling task_set_special_port, task_set_exception_ports + * and/or audit_session_spawnjoin for the current task. * - * Parameters: struct image_params * the image parameter block - * int * a pointer to the stack offset variable + * Parameters: struct image_params * Image parameter block * * Returns: 0 Success - * !0 Faiure: errno - * - * Implicit returns: - * (*stackp) The stack offset, modified - * - * Note: The strings segment layout is backward, from the beginning - * of the top of the stack to consume the minimal amount of - * space possible; the returned stack pointer points to the - * end of the area consumed (stacks grow upward). - * - * argc is an int; arg[i] are pointers; env[i] are pointers; - * exec_path is a pointer; the 0's are (void *)NULL's - * - * The stack frame layout is: - * - * +-------------+ - * sp-> | argc | - * +-------------+ - * | arg[0] | - * +-------------+ - * : - * : - * +-------------+ - * | arg[argc-1] | - * +-------------+ - * | 0 | - * +-------------+ - * | env[0] | - * +-------------+ - * : - * : - * +-------------+ - * | env[n] | - * +-------------+ - * | 0 | - * +-------------+ - * | exec_path | In MacOS X PR2 Beaker2E the path passed to exec() is - * +-------------+ passed on the stack just after the trailing 0 of the - * | 0 | the envp[] array as a pointer to a string. - * +-------------+ - * | PATH AREA | - * +-------------+ - * | STRING AREA | - * : - * : - * | | <- p->user_stack - * +-------------+ - * - * Although technically a part of the STRING AREA, we treat the PATH AREA as - * a separate entity. This allows us to align the beginning of the PATH AREA - * to a pointer boundary so that the exec_path, env[i], and argv[i] pointers - * which preceed it on the stack are properly aligned. - * - * TODO: argc copied with suword(), which takes a 64 bit address + * EINVAL Failure + * ENOTSUP Illegal posix_spawn attr flag was set */ -static int -exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp) +static errno_t +exec_handle_port_actions(struct image_params *imgp, boolean_t * portwatch_present, + ipc_port_t * portwatch_ports) { - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - int ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4; - char *argv = imgp->ip_argv; /* modifiable copy of argv */ - user_addr_t string_area; /* *argv[], *env[] */ - user_addr_t path_area; /* package launch path */ - user_addr_t ptr_area; /* argv[], env[], exec_path */ - user_addr_t stack; - int stringc = imgp->ip_argc + imgp->ip_envc; - int len; - int error; - int strspace; - - stack = *stackp; + _posix_spawn_port_actions_t pacts = imgp->ip_px_spa; +#if CONFIG_AUDIT + proc_t p = vfs_context_proc(imgp->ip_vfs_context); +#endif + _ps_port_action_t *act = NULL; + task_t task = get_threadtask(imgp->ip_new_thread); + ipc_port_t port = NULL; + errno_t ret = 0; + int i; + kern_return_t kr; - /* - * Set up pointers to the beginning of the string area, the beginning - * of the path area, and the beginning of the pointer area (actually, - * the location of argc, an int, which may be smaller than a pointer, - * but we use ptr_size worth of space for it, for alignment). - */ - string_area = stack - (((imgp->ip_strendp - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1)) - ptr_size; - path_area = string_area - (((imgp->ip_argv - imgp->ip_strings) + ptr_size-1) & ~(ptr_size-1)); - ptr_area = path_area - ((imgp->ip_argc + imgp->ip_envc + 4) * ptr_size) - ptr_size /*argc*/; + *portwatch_present = FALSE; - /* Return the initial stack address: the location of argc */ - *stackp = ptr_area; + for (i = 0; i < pacts->pspa_count; i++) { + act = &pacts->pspa_actions[i]; - /* - * Record the size of the arguments area so that sysctl_procargs() - * can return the argument area without having to parse the arguments. - */ - p->p_argc = imgp->ip_argc; - p->p_argslen = (int)(stack - path_area); + if (MACH_PORT_VALID(act->new_port)) { + kr = ipc_object_copyin(get_task_ipcspace(current_task()), + act->new_port, MACH_MSG_TYPE_COPY_SEND, + (ipc_object_t *) &port); + if (kr != KERN_SUCCESS) { + ret = EINVAL; + goto done; + } + } else { + /* it's NULL or DEAD */ + port = CAST_MACH_NAME_TO_PORT(act->new_port); + } - /* - * Support for new app package launching for Mac OS X allocates - * the "path" at the begining of the imgp->ip_strings buffer. - * copy it just before the string area. - */ - len = 0; - error = copyoutstr(imgp->ip_strings, path_area, - (unsigned)(imgp->ip_argv - imgp->ip_strings), - (size_t *)&len); - if (error) - goto bad; + switch (act->port_type) { + case PSPA_SPECIAL: + kr = task_set_special_port(task, act->which, port); + if (kr != KERN_SUCCESS) { + ret = EINVAL; + } + break; - /* Save a NULL pointer below it */ - (void)copyoutptr(0LL, path_area - ptr_size, ptr_size); + case PSPA_EXCEPTION: + kr = task_set_exception_ports(task, act->mask, port, + act->behavior, act->flavor); + if (kr != KERN_SUCCESS) { + ret = EINVAL; + } + break; +#if CONFIG_AUDIT + case PSPA_AU_SESSION: + ret = audit_session_spawnjoin(p, task, port); + if (ret) { + /* audit_session_spawnjoin() has already dropped the reference in case of error. */ + goto done; + } - /* Save the pointer to "path" just below it */ - (void)copyoutptr(path_area, path_area - 2*ptr_size, ptr_size); + break; +#endif + case PSPA_IMP_WATCHPORTS: + if (portwatch_ports != NULL && IPC_PORT_VALID(port)) { + *portwatch_present = TRUE; + /* hold on to this till end of spawn */ + portwatch_ports[i] = port; + } else { + ipc_port_release_send(port); + } - /* - * ptr_size for 2 NULL one each ofter arg[argc -1] and env[n] - * ptr_size for argc - * skip over saved path, ptr_size for pointer to path, - * and ptr_size for the NULL after pointer to path. - */ + break; + default: + ret = EINVAL; + break; + } - /* argc (int32, stored in a ptr_size area) */ - (void)suword(ptr_area, imgp->ip_argc); - ptr_area += sizeof(int); - /* pad to ptr_size, if 64 bit image, to ensure user stack alignment */ - if (imgp->ip_flags & IMGPF_IS_64BIT) { - (void)suword(ptr_area, 0); /* int, not long: ignored */ - ptr_area += sizeof(int); + if (ret) { + /* action failed, so release port resources */ + ipc_port_release_send(port); + break; + } } +done: + if (0 != ret) { + DTRACE_PROC1(spawn__port__failure, mach_port_name_t, act->new_port); + } + return ret; +} + +/* + * exec_handle_file_actions + * + * Description: Go through the _posix_file_actions_t contents applying the + * open, close, and dup2 operations to the open file table for + * the current process. + * + * Parameters: struct image_params * Image parameter block + * + * Returns: 0 Success + * ??? + * + * Note: Actions are applied in the order specified, with the credential + * of the parent process. This is done to permit the parent + * process to utilize POSIX_SPAWN_RESETIDS to drop privilege in + * the child following operations the child may in fact not be + * normally permitted to perform. + */ +static int +exec_handle_file_actions(struct image_params *imgp, short psa_flags) +{ + int error = 0; + int action; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + _posix_spawn_file_actions_t px_sfap = imgp->ip_px_sfa; + int ival[2]; /* dummy retval for system calls) */ + + for (action = 0; action < px_sfap->psfa_act_count; action++) { + _psfa_action_t *psfa = &px_sfap->psfa_act_acts[action]; + + switch (psfa->psfaa_type) { + case PSFA_OPEN: { + /* + * Open is different, in that it requires the use of + * a path argument, which is normally copied in from + * user space; because of this, we have to support an + * open from kernel space that passes an address space + * context of UIO_SYSSPACE, and casts the address + * argument to a user_addr_t. + */ + char *bufp = NULL; + struct vnode_attr *vap; + struct nameidata *ndp; + int mode = psfa->psfaa_openargs.psfao_mode; + struct dup2_args dup2a; + struct close_nocancel_args ca; + int origfd; + + MALLOC(bufp, char *, sizeof(*vap) + sizeof(*ndp), M_TEMP, M_WAITOK | M_ZERO); + if (bufp == NULL) { + error = ENOMEM; + break; + } + + vap = (struct vnode_attr *) bufp; + ndp = (struct nameidata *) (bufp + sizeof(*vap)); + + VATTR_INIT(vap); + /* Mask off all but regular access permissions */ + mode = ((mode & ~p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT; + VATTR_SET(vap, va_mode, mode & ACCESSPERMS); + + NDINIT(ndp, LOOKUP, OP_OPEN, FOLLOW | AUDITVNPATH1, UIO_SYSSPACE, + CAST_USER_ADDR_T(psfa->psfaa_openargs.psfao_path), + imgp->ip_vfs_context); + + error = open1(imgp->ip_vfs_context, + ndp, + psfa->psfaa_openargs.psfao_oflag, + vap, + fileproc_alloc_init, NULL, + ival); + + FREE(bufp, M_TEMP); + + /* + * If there's an error, or we get the right fd by + * accident, then drop out here. This is easier than + * reworking all the open code to preallocate fd + * slots, and internally taking one as an argument. + */ + if (error || ival[0] == psfa->psfaa_filedes) { + break; + } + + origfd = ival[0]; + /* + * If we didn't fall out from an error, we ended up + * with the wrong fd; so now we've got to try to dup2 + * it to the right one. + */ + dup2a.from = origfd; + dup2a.to = psfa->psfaa_filedes; + + /* + * The dup2() system call implementation sets + * ival to newfd in the success case, but we + * can ignore that, since if we didn't get the + * fd we wanted, the error will stop us. + */ + error = dup2(p, &dup2a, ival); + if (error) { + break; + } + + /* + * Finally, close the original fd. + */ + ca.fd = origfd; + + error = close_nocancel(p, &ca, ival); + } + break; + + case PSFA_DUP2: { + struct dup2_args dup2a; + + dup2a.from = psfa->psfaa_filedes; + dup2a.to = psfa->psfaa_openargs.psfao_oflag; + + /* + * The dup2() system call implementation sets + * ival to newfd in the success case, but we + * can ignore that, since if we didn't get the + * fd we wanted, the error will stop us. + */ + error = dup2(p, &dup2a, ival); + } + break; + + case PSFA_CLOSE: { + struct close_nocancel_args ca; + + ca.fd = psfa->psfaa_filedes; + + error = close_nocancel(p, &ca, ival); + } + break; + + case PSFA_INHERIT: { + struct fcntl_nocancel_args fcntla; + + /* + * Check to see if the descriptor exists, and + * ensure it's -not- marked as close-on-exec. + * + * Attempting to "inherit" a guarded fd will + * result in a error. + */ + fcntla.fd = psfa->psfaa_filedes; + fcntla.cmd = F_GETFD; + if ((error = fcntl_nocancel(p, &fcntla, ival)) != 0) { + break; + } + + if ((ival[0] & FD_CLOEXEC) == FD_CLOEXEC) { + fcntla.fd = psfa->psfaa_filedes; + fcntla.cmd = F_SETFD; + fcntla.arg = ival[0] & ~FD_CLOEXEC; + error = fcntl_nocancel(p, &fcntla, ival); + } + } + break; + + default: + error = EINVAL; + break; + } + + /* All file actions failures are considered fatal, per POSIX */ + + if (error) { + if (PSFA_OPEN == psfa->psfaa_type) { + DTRACE_PROC1(spawn__open__failure, uintptr_t, + psfa->psfaa_openargs.psfao_path); + } else { + DTRACE_PROC1(spawn__fd__failure, int, psfa->psfaa_filedes); + } + break; + } + } + + if (error != 0 || (psa_flags & POSIX_SPAWN_CLOEXEC_DEFAULT) == 0) { + return error; + } + + /* + * If POSIX_SPAWN_CLOEXEC_DEFAULT is set, behave (during + * this spawn only) as if "close on exec" is the default + * disposition of all pre-existing file descriptors. In this case, + * the list of file descriptors mentioned in the file actions + * are the only ones that can be inherited, so mark them now. + * + * The actual closing part comes later, in fdexec(). + */ + proc_fdlock(p); + for (action = 0; action < px_sfap->psfa_act_count; action++) { + _psfa_action_t *psfa = &px_sfap->psfa_act_acts[action]; + int fd = psfa->psfaa_filedes; + + switch (psfa->psfaa_type) { + case PSFA_DUP2: + fd = psfa->psfaa_openargs.psfao_oflag; + /*FALLTHROUGH*/ + case PSFA_OPEN: + case PSFA_INHERIT: + *fdflags(p, fd) |= UF_INHERIT; + break; + + case PSFA_CLOSE: + break; + } + } + proc_fdunlock(p); + + return 0; +} + +#if CONFIG_MACF +/* + * exec_spawnattr_getmacpolicyinfo + */ +void * +exec_spawnattr_getmacpolicyinfo(const void *macextensions, const char *policyname, size_t *lenp) +{ + const struct _posix_spawn_mac_policy_extensions *psmx = macextensions; + int i; + + if (psmx == NULL) { + return NULL; + } + + for (i = 0; i < psmx->psmx_count; i++) { + const _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i]; + if (strncmp(extension->policyname, policyname, sizeof(extension->policyname)) == 0) { + if (lenp != NULL) { + *lenp = extension->datalen; + } + return extension->datap; + } + } + + if (lenp != NULL) { + *lenp = 0; + } + return NULL; +} + +static int +spawn_copyin_macpolicyinfo(const struct user__posix_spawn_args_desc *px_args, _posix_spawn_mac_policy_extensions_t *psmxp) +{ + _posix_spawn_mac_policy_extensions_t psmx = NULL; + int error = 0; + int copycnt = 0; + int i = 0; + + *psmxp = NULL; + + if (px_args->mac_extensions_size < PS_MAC_EXTENSIONS_SIZE(1) || + px_args->mac_extensions_size > PAGE_SIZE) { + error = EINVAL; + goto bad; + } + + MALLOC(psmx, _posix_spawn_mac_policy_extensions_t, px_args->mac_extensions_size, M_TEMP, M_WAITOK); + if ((error = copyin(px_args->mac_extensions, psmx, px_args->mac_extensions_size)) != 0) { + goto bad; + } + + size_t extsize = PS_MAC_EXTENSIONS_SIZE(psmx->psmx_count); + if (extsize == 0 || extsize > px_args->mac_extensions_size) { + error = EINVAL; + goto bad; + } + + for (i = 0; i < psmx->psmx_count; i++) { + _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[i]; + if (extension->datalen == 0 || extension->datalen > PAGE_SIZE) { + error = EINVAL; + goto bad; + } + } + + for (copycnt = 0; copycnt < psmx->psmx_count; copycnt++) { + _ps_mac_policy_extension_t *extension = &psmx->psmx_extensions[copycnt]; + void *data = NULL; + + MALLOC(data, void *, extension->datalen, M_TEMP, M_WAITOK); + if ((error = copyin(extension->data, data, extension->datalen)) != 0) { + FREE(data, M_TEMP); + goto bad; + } + extension->datap = data; + } + + *psmxp = psmx; + return 0; + +bad: + if (psmx != NULL) { + for (i = 0; i < copycnt; i++) { + FREE(psmx->psmx_extensions[i].datap, M_TEMP); + } + FREE(psmx, M_TEMP); + } + return error; +} + +static void +spawn_free_macpolicyinfo(_posix_spawn_mac_policy_extensions_t psmx) +{ + int i; + + if (psmx == NULL) { + return; + } + for (i = 0; i < psmx->psmx_count; i++) { + FREE(psmx->psmx_extensions[i].datap, M_TEMP); + } + FREE(psmx, M_TEMP); +} +#endif /* CONFIG_MACF */ + +#if CONFIG_COALITIONS +static inline void +spawn_coalitions_release_all(coalition_t coal[COALITION_NUM_TYPES]) +{ + for (int c = 0; c < COALITION_NUM_TYPES; c++) { + if (coal[c]) { + coalition_remove_active(coal[c]); + coalition_release(coal[c]); + } + } +} +#endif + +#if CONFIG_PERSONAS +static int +spawn_validate_persona(struct _posix_spawn_persona_info *px_persona) +{ + int error = 0; + struct persona *persona = NULL; + int verify = px_persona->pspi_flags & POSIX_SPAWN_PERSONA_FLAGS_VERIFY; + + /* + * TODO: rdar://problem/19981151 + * Add entitlement check! + */ + if (!kauth_cred_issuser(kauth_cred_get())) { + return EPERM; + } + + persona = persona_lookup(px_persona->pspi_id); + if (!persona) { + error = ESRCH; + goto out; + } + + if (verify) { + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_UID) { + if (px_persona->pspi_uid != persona_get_uid(persona)) { + error = EINVAL; + goto out; + } + } + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GID) { + if (px_persona->pspi_gid != persona_get_gid(persona)) { + error = EINVAL; + goto out; + } + } + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GROUPS) { + unsigned ngroups = 0; + gid_t groups[NGROUPS_MAX]; + + if (persona_get_groups(persona, &ngroups, groups, + px_persona->pspi_ngroups) != 0) { + error = EINVAL; + goto out; + } + if (ngroups != px_persona->pspi_ngroups) { + error = EINVAL; + goto out; + } + while (ngroups--) { + if (px_persona->pspi_groups[ngroups] != groups[ngroups]) { + error = EINVAL; + goto out; + } + } + if (px_persona->pspi_gmuid != persona_get_gmuid(persona)) { + error = EINVAL; + goto out; + } + } + } + +out: + if (persona) { + persona_put(persona); + } + + return error; +} + +static int +spawn_persona_adopt(proc_t p, struct _posix_spawn_persona_info *px_persona) +{ + int ret; + kauth_cred_t cred; + struct persona *persona = NULL; + int override = !!(px_persona->pspi_flags & POSIX_SPAWN_PERSONA_FLAGS_OVERRIDE); + + if (!override) { + return persona_proc_adopt_id(p, px_persona->pspi_id, NULL); + } + + /* + * we want to spawn into the given persona, but we want to override + * the kauth with a different UID/GID combo + */ + persona = persona_lookup(px_persona->pspi_id); + if (!persona) { + return ESRCH; + } + + cred = persona_get_cred(persona); + if (!cred) { + ret = EINVAL; + goto out; + } + + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_UID) { + cred = kauth_cred_setresuid(cred, + px_persona->pspi_uid, + px_persona->pspi_uid, + px_persona->pspi_uid, + KAUTH_UID_NONE); + } + + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GID) { + cred = kauth_cred_setresgid(cred, + px_persona->pspi_gid, + px_persona->pspi_gid, + px_persona->pspi_gid); + } + + if (px_persona->pspi_flags & POSIX_SPAWN_PERSONA_GROUPS) { + cred = kauth_cred_setgroups(cred, + px_persona->pspi_groups, + px_persona->pspi_ngroups, + px_persona->pspi_gmuid); + } + + ret = persona_proc_adopt(p, persona, cred); + +out: + persona_put(persona); + return ret; +} +#endif + +#if __arm64__ +static inline void +proc_legacy_footprint(proc_t p, task_t task, const char *caller) +{ + boolean_t legacy_footprint_entitled; + + legacy_footprint_entitled = IOTaskHasEntitlement(task, + "com.apple.private.memory.legacy_footprint"); + if (legacy_footprint_entitled) { + printf("%s: %d[%s] legacy footprint (entitled)\n", + caller, p->p_pid, p->p_name); + task_set_legacy_footprint(task, TRUE); + } +} +#endif /* __arm64__ */ + +/* + * posix_spawn + * + * Parameters: uap->pid Pointer to pid return area + * uap->fname File name to exec + * uap->argp Argument list + * uap->envp Environment list + * + * Returns: 0 Success + * EINVAL Invalid argument + * ENOTSUP Not supported + * ENOEXEC Executable file format error + * exec_activate_image:EINVAL Invalid argument + * exec_activate_image:EACCES Permission denied + * exec_activate_image:EINTR Interrupted function + * exec_activate_image:ENOMEM Not enough space + * exec_activate_image:EFAULT Bad address + * exec_activate_image:ENAMETOOLONG Filename too long + * exec_activate_image:ENOEXEC Executable file format error + * exec_activate_image:ETXTBSY Text file busy [misuse of error code] + * exec_activate_image:EBADEXEC The executable is corrupt/unknown + * exec_activate_image:??? + * mac_execve_enter:??? + * + * TODO: Expect to need __mac_posix_spawn() at some point... + * Handle posix_spawnattr_t + * Handle posix_spawn_file_actions_t + */ +int +posix_spawn(proc_t ap, struct posix_spawn_args *uap, int32_t *retval) +{ + proc_t p = ap; /* quiet bogus GCC vfork() warning */ + user_addr_t pid = uap->pid; + int ival[2]; /* dummy retval for setpgid() */ + char *bufp = NULL; + struct image_params *imgp; + struct vnode_attr *vap; + struct vnode_attr *origvap; + struct uthread *uthread = 0; /* compiler complains if not set to 0*/ + int error, sig; + int is_64 = IS_64BIT_PROCESS(p); + struct vfs_context context; + struct user__posix_spawn_args_desc px_args; + struct _posix_spawnattr px_sa; + _posix_spawn_file_actions_t px_sfap = NULL; + _posix_spawn_port_actions_t px_spap = NULL; + struct __kern_sigaction vec; + boolean_t spawn_no_exec = FALSE; + boolean_t proc_transit_set = TRUE; + boolean_t exec_done = FALSE; + int portwatch_count = 0; + ipc_port_t * portwatch_ports = NULL; + vm_size_t px_sa_offset = offsetof(struct _posix_spawnattr, psa_ports); + task_t old_task = current_task(); + task_t new_task = NULL; + boolean_t should_release_proc_ref = FALSE; + void *inherit = NULL; +#if CONFIG_PERSONAS + struct _posix_spawn_persona_info *px_persona = NULL; +#endif + + /* + * Allocate a big chunk for locals instead of using stack since these + * structures are pretty big. + */ + MALLOC(bufp, char *, (sizeof(*imgp) + sizeof(*vap) + sizeof(*origvap)), M_TEMP, M_WAITOK | M_ZERO); + imgp = (struct image_params *) bufp; + if (bufp == NULL) { + error = ENOMEM; + goto bad; + } + vap = (struct vnode_attr *) (bufp + sizeof(*imgp)); + origvap = (struct vnode_attr *) (bufp + sizeof(*imgp) + sizeof(*vap)); + + /* Initialize the common data in the image_params structure */ + imgp->ip_user_fname = uap->path; + imgp->ip_user_argv = uap->argv; + imgp->ip_user_envv = uap->envp; + imgp->ip_vattr = vap; + imgp->ip_origvattr = origvap; + imgp->ip_vfs_context = &context; + imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT_ADDR : IMGPF_NONE); + imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); + imgp->ip_mac_return = 0; + imgp->ip_px_persona = NULL; + imgp->ip_cs_error = OS_REASON_NULL; + + if (uap->adesc != USER_ADDR_NULL) { + if (is_64) { + error = copyin(uap->adesc, &px_args, sizeof(px_args)); + } else { + struct user32__posix_spawn_args_desc px_args32; + + error = copyin(uap->adesc, &px_args32, sizeof(px_args32)); + + /* + * Convert arguments descriptor from external 32 bit + * representation to internal 64 bit representation + */ + px_args.attr_size = px_args32.attr_size; + px_args.attrp = CAST_USER_ADDR_T(px_args32.attrp); + px_args.file_actions_size = px_args32.file_actions_size; + px_args.file_actions = CAST_USER_ADDR_T(px_args32.file_actions); + px_args.port_actions_size = px_args32.port_actions_size; + px_args.port_actions = CAST_USER_ADDR_T(px_args32.port_actions); + px_args.mac_extensions_size = px_args32.mac_extensions_size; + px_args.mac_extensions = CAST_USER_ADDR_T(px_args32.mac_extensions); + px_args.coal_info_size = px_args32.coal_info_size; + px_args.coal_info = CAST_USER_ADDR_T(px_args32.coal_info); + px_args.persona_info_size = px_args32.persona_info_size; + px_args.persona_info = CAST_USER_ADDR_T(px_args32.persona_info); + } + if (error) { + goto bad; + } + + if (px_args.attr_size != 0) { + /* + * We are not copying the port_actions pointer, + * because we already have it from px_args. + * This is a bit fragile: + */ + + if ((error = copyin(px_args.attrp, &px_sa, px_sa_offset)) != 0) { + goto bad; + } + + bzero((void *)((unsigned long) &px_sa + px_sa_offset), sizeof(px_sa) - px_sa_offset ); + + imgp->ip_px_sa = &px_sa; + } + if (px_args.file_actions_size != 0) { + /* Limit file_actions to allowed number of open files */ + int maxfa = (p->p_limit ? p->p_rlimit[RLIMIT_NOFILE].rlim_cur : NOFILE); + size_t maxfa_size = PSF_ACTIONS_SIZE(maxfa); + if (px_args.file_actions_size < PSF_ACTIONS_SIZE(1) || + maxfa_size == 0 || px_args.file_actions_size > maxfa_size) { + error = EINVAL; + goto bad; + } + MALLOC(px_sfap, _posix_spawn_file_actions_t, px_args.file_actions_size, M_TEMP, M_WAITOK); + if (px_sfap == NULL) { + error = ENOMEM; + goto bad; + } + imgp->ip_px_sfa = px_sfap; + + if ((error = copyin(px_args.file_actions, px_sfap, + px_args.file_actions_size)) != 0) { + goto bad; + } + + /* Verify that the action count matches the struct size */ + size_t psfsize = PSF_ACTIONS_SIZE(px_sfap->psfa_act_count); + if (psfsize == 0 || psfsize != px_args.file_actions_size) { + error = EINVAL; + goto bad; + } + } + if (px_args.port_actions_size != 0) { + /* Limit port_actions to one page of data */ + if (px_args.port_actions_size < PS_PORT_ACTIONS_SIZE(1) || + px_args.port_actions_size > PAGE_SIZE) { + error = EINVAL; + goto bad; + } + + MALLOC(px_spap, _posix_spawn_port_actions_t, + px_args.port_actions_size, M_TEMP, M_WAITOK); + if (px_spap == NULL) { + error = ENOMEM; + goto bad; + } + imgp->ip_px_spa = px_spap; + + if ((error = copyin(px_args.port_actions, px_spap, + px_args.port_actions_size)) != 0) { + goto bad; + } + + /* Verify that the action count matches the struct size */ + size_t pasize = PS_PORT_ACTIONS_SIZE(px_spap->pspa_count); + if (pasize == 0 || pasize != px_args.port_actions_size) { + error = EINVAL; + goto bad; + } + } +#if CONFIG_PERSONAS + /* copy in the persona info */ + if (px_args.persona_info_size != 0 && px_args.persona_info != 0) { + /* for now, we need the exact same struct in user space */ + if (px_args.persona_info_size != sizeof(*px_persona)) { + error = ERANGE; + goto bad; + } + + MALLOC(px_persona, struct _posix_spawn_persona_info *, px_args.persona_info_size, M_TEMP, M_WAITOK | M_ZERO); + if (px_persona == NULL) { + error = ENOMEM; + goto bad; + } + imgp->ip_px_persona = px_persona; + + if ((error = copyin(px_args.persona_info, px_persona, + px_args.persona_info_size)) != 0) { + goto bad; + } + if ((error = spawn_validate_persona(px_persona)) != 0) { + goto bad; + } + } +#endif +#if CONFIG_MACF + if (px_args.mac_extensions_size != 0) { + if ((error = spawn_copyin_macpolicyinfo(&px_args, (_posix_spawn_mac_policy_extensions_t *)&imgp->ip_px_smpx)) != 0) { + goto bad; + } + } +#endif /* CONFIG_MACF */ + } + + /* set uthread to parent */ + uthread = get_bsdthread_info(current_thread()); + + /* + * ; this does not result in a behaviour change + * relative to Leopard, so there should not be any existing code + * which depends on it. + */ + if (uthread->uu_flag & UT_VFORK) { + error = EINVAL; + goto bad; + } + + /* + * If we don't have the extension flag that turns "posix_spawn()" + * into "execve() with options", then we will be creating a new + * process which does not inherit memory from the parent process, + * which is one of the most expensive things about using fork() + * and execve(). + */ + if (imgp->ip_px_sa == NULL || !(px_sa.psa_flags & POSIX_SPAWN_SETEXEC)) { + /* Set the new task's coalition, if it is requested. */ + coalition_t coal[COALITION_NUM_TYPES] = { COALITION_NULL }; +#if CONFIG_COALITIONS + int i, ncoals; + kern_return_t kr = KERN_SUCCESS; + struct _posix_spawn_coalition_info coal_info; + int coal_role[COALITION_NUM_TYPES]; + + if (imgp->ip_px_sa == NULL || !px_args.coal_info) { + goto do_fork1; + } + + memset(&coal_info, 0, sizeof(coal_info)); + + if (px_args.coal_info_size > sizeof(coal_info)) { + px_args.coal_info_size = sizeof(coal_info); + } + error = copyin(px_args.coal_info, + &coal_info, px_args.coal_info_size); + if (error != 0) { + goto bad; + } + + ncoals = 0; + for (i = 0; i < COALITION_NUM_TYPES; i++) { + uint64_t cid = coal_info.psci_info[i].psci_id; + if (cid != 0) { + /* + * don't allow tasks which are not in a + * privileged coalition to spawn processes + * into coalitions other than their own + */ + if (!task_is_in_privileged_coalition(p->task, i)) { + coal_dbg("ERROR: %d not in privilegd " + "coalition of type %d", + p->p_pid, i); + spawn_coalitions_release_all(coal); + error = EPERM; + goto bad; + } + + coal_dbg("searching for coalition id:%llu", cid); + /* + * take a reference and activation on the + * coalition to guard against free-while-spawn + * races + */ + coal[i] = coalition_find_and_activate_by_id(cid); + if (coal[i] == COALITION_NULL) { + coal_dbg("could not find coalition id:%llu " + "(perhaps it has been terminated or reaped)", cid); + /* + * release any other coalition's we + * may have a reference to + */ + spawn_coalitions_release_all(coal); + error = ESRCH; + goto bad; + } + if (coalition_type(coal[i]) != i) { + coal_dbg("coalition with id:%lld is not of type:%d" + " (it's type:%d)", cid, i, coalition_type(coal[i])); + error = ESRCH; + goto bad; + } + coal_role[i] = coal_info.psci_info[i].psci_role; + ncoals++; + } + } + if (ncoals < COALITION_NUM_TYPES) { + /* + * If the user is attempting to spawn into a subset of + * the known coalition types, then make sure they have + * _at_least_ specified a resource coalition. If not, + * the following fork1() call will implicitly force an + * inheritance from 'p' and won't actually spawn the + * new task into the coalitions the user specified. + * (also the call to coalitions_set_roles will panic) + */ + if (coal[COALITION_TYPE_RESOURCE] == COALITION_NULL) { + spawn_coalitions_release_all(coal); + error = EINVAL; + goto bad; + } + } +do_fork1: +#endif /* CONFIG_COALITIONS */ + + /* + * note that this will implicitly inherit the + * caller's persona (if it exists) + */ + error = fork1(p, &imgp->ip_new_thread, PROC_CREATE_SPAWN, coal); + /* returns a thread and task reference */ + + if (error == 0) { + new_task = get_threadtask(imgp->ip_new_thread); + } +#if CONFIG_COALITIONS + /* set the roles of this task within each given coalition */ + if (error == 0) { + kr = coalitions_set_roles(coal, new_task, coal_role); + if (kr != KERN_SUCCESS) { + error = EINVAL; + } + if (kdebug_debugid_enabled(MACHDBG_CODE(DBG_MACH_COALITION, + MACH_COALITION_ADOPT))) { + for (i = 0; i < COALITION_NUM_TYPES; i++) { + if (coal[i] != COALITION_NULL) { + /* + * On 32-bit targets, uniqueid + * will get truncated to 32 bits + */ + KDBG_RELEASE(MACHDBG_CODE( + DBG_MACH_COALITION, + MACH_COALITION_ADOPT), + coalition_id(coal[i]), + get_task_uniqueid(new_task)); + } + } + } + } + + /* drop our references and activations - fork1() now holds them */ + spawn_coalitions_release_all(coal); +#endif /* CONFIG_COALITIONS */ + if (error != 0) { + goto bad; + } + imgp->ip_flags |= IMGPF_SPAWN; /* spawn w/o exec */ + spawn_no_exec = TRUE; /* used in later tests */ + +#if CONFIG_PERSONAS + /* + * If the parent isn't in a persona (launchd), and + * hasn't specified a new persona for the process, + * then we'll put the process into the system persona + * + * TODO: this will have to be re-worked because as of + * now, without any launchd adoption, the resulting + * xpcproxy process will not have sufficient + * privileges to setuid/gid. + */ +#if 0 + if (!proc_has_persona(p) && imgp->ip_px_persona == NULL) { + MALLOC(px_persona, struct _posix_spawn_persona_info *, + sizeof(*px_persona), M_TEMP, M_WAITOK | M_ZERO); + if (px_persona == NULL) { + error = ENOMEM; + goto bad; + } + px_persona->pspi_id = persona_get_id(g_system_persona); + imgp->ip_px_persona = px_persona; + } +#endif /* 0 */ +#endif /* CONFIG_PERSONAS */ + } else { + /* + * For execve case, create a new task and thread + * which points to current_proc. The current_proc will point + * to the new task after image activation and proc ref drain. + * + * proc (current_proc) <----- old_task (current_task) + * ^ | ^ + * | | | + * | ---------------------------------- + * | + * --------- new_task (task marked as TF_EXEC_COPY) + * + * After image activation, the proc will point to the new task + * and would look like following. + * + * proc (current_proc) <----- old_task (current_task, marked as TPF_DID_EXEC) + * ^ | + * | | + * | ----------> new_task + * | | + * ----------------- + * + * During exec any transition from new_task -> proc is fine, but don't allow + * transition from proc->task, since it will modify old_task. + */ + imgp->ip_new_thread = fork_create_child(old_task, + NULL, + p, + FALSE, + p->p_flag & P_LP64, + task_get_64bit_data(old_task), + TRUE); + /* task and thread ref returned by fork_create_child */ + if (imgp->ip_new_thread == NULL) { + error = ENOMEM; + goto bad; + } + + new_task = get_threadtask(imgp->ip_new_thread); + imgp->ip_flags |= IMGPF_EXEC; + } + + if (spawn_no_exec) { + p = (proc_t)get_bsdthreadtask_info(imgp->ip_new_thread); + + /* + * We had to wait until this point before firing the + * proc:::create probe, otherwise p would not point to the + * child process. + */ + DTRACE_PROC1(create, proc_t, p); + } + assert(p != NULL); + + context.vc_thread = imgp->ip_new_thread; + context.vc_ucred = p->p_ucred; /* XXX must NOT be kauth_cred_get() */ + + /* + * Post fdcopy(), pre exec_handle_sugid() - this is where we want + * to handle the file_actions. Since vfork() also ends up setting + * us into the parent process group, and saved off the signal flags, + * this is also where we want to handle the spawn flags. + */ + + /* Has spawn file actions? */ + if (imgp->ip_px_sfa != NULL) { + /* + * The POSIX_SPAWN_CLOEXEC_DEFAULT flag + * is handled in exec_handle_file_actions(). + */ + if ((error = exec_handle_file_actions(imgp, + imgp->ip_px_sa != NULL ? px_sa.psa_flags : 0)) != 0) { + goto bad; + } + } + + /* Has spawn port actions? */ + if (imgp->ip_px_spa != NULL) { + boolean_t is_adaptive = FALSE; + boolean_t portwatch_present = FALSE; + + /* Will this process become adaptive? The apptype isn't ready yet, so we can't look there. */ + if (imgp->ip_px_sa != NULL && px_sa.psa_apptype == POSIX_SPAWN_PROC_TYPE_DAEMON_ADAPTIVE) { + is_adaptive = TRUE; + } + + /* + * portwatch only: + * Allocate a place to store the ports we want to bind to the new task + * We can't bind them until after the apptype is set. + */ + if (px_spap->pspa_count != 0 && is_adaptive) { + portwatch_count = px_spap->pspa_count; + MALLOC(portwatch_ports, ipc_port_t *, (sizeof(ipc_port_t) * portwatch_count), M_TEMP, M_WAITOK | M_ZERO); + } else { + portwatch_ports = NULL; + } + + if ((error = exec_handle_port_actions(imgp, &portwatch_present, portwatch_ports)) != 0) { + goto bad; + } + + if (portwatch_present == FALSE && portwatch_ports != NULL) { + FREE(portwatch_ports, M_TEMP); + portwatch_ports = NULL; + portwatch_count = 0; + } + } + + /* Has spawn attr? */ + if (imgp->ip_px_sa != NULL) { + /* + * Set the process group ID of the child process; this has + * to happen before the image activation. + */ + if (px_sa.psa_flags & POSIX_SPAWN_SETPGROUP) { + struct setpgid_args spga; + spga.pid = p->p_pid; + spga.pgid = px_sa.psa_pgroup; + /* + * Effectively, call setpgid() system call; works + * because there are no pointer arguments. + */ + if ((error = setpgid(p, &spga, ival)) != 0) { + goto bad; + } + } + + /* + * Reset UID/GID to parent's RUID/RGID; This works only + * because the operation occurs *after* the vfork() and + * before the call to exec_handle_sugid() by the image + * activator called from exec_activate_image(). POSIX + * requires that any setuid/setgid bits on the process + * image will take precedence over the spawn attributes + * (re)setting them. + * + * Modifications to p_ucred must be guarded using the + * proc's ucred lock. This prevents others from accessing + * a garbage credential. + */ + while (px_sa.psa_flags & POSIX_SPAWN_RESETIDS) { + kauth_cred_t my_cred = kauth_cred_proc_ref(p); + kauth_cred_t my_new_cred = kauth_cred_setuidgid(my_cred, kauth_cred_getruid(my_cred), kauth_cred_getrgid(my_cred)); + + if (my_cred == my_new_cred) { + kauth_cred_unref(&my_cred); + break; + } + + /* update cred on proc */ + proc_ucred_lock(p); + + if (p->p_ucred != my_cred) { + proc_ucred_unlock(p); + kauth_cred_unref(&my_new_cred); + continue; + } + + /* donate cred reference on my_new_cred to p->p_ucred */ + p->p_ucred = my_new_cred; + PROC_UPDATE_CREDS_ONPROC(p); + proc_ucred_unlock(p); + + /* drop additional reference that was taken on the previous cred */ + kauth_cred_unref(&my_cred); + } + +#if CONFIG_PERSONAS + if (spawn_no_exec && imgp->ip_px_persona != NULL) { + /* + * If we were asked to spawn a process into a new persona, + * do the credential switch now (which may override the UID/GID + * inherit done just above). It's important to do this switch + * before image activation both for reasons stated above, and + * to ensure that the new persona has access to the image/file + * being executed. + */ + error = spawn_persona_adopt(p, imgp->ip_px_persona); + if (error != 0) { + goto bad; + } + } +#endif /* CONFIG_PERSONAS */ +#if !SECURE_KERNEL + /* + * Disable ASLR for the spawned process. + * + * But only do so if we are not embedded + RELEASE. + * While embedded allows for a boot-arg (-disable_aslr) + * to deal with this (which itself is only honored on + * DEVELOPMENT or DEBUG builds of xnu), it is often + * useful or necessary to disable ASLR on a per-process + * basis for unit testing and debugging. + */ + if (px_sa.psa_flags & _POSIX_SPAWN_DISABLE_ASLR) { + OSBitOrAtomic(P_DISABLE_ASLR, &p->p_flag); + } +#endif /* !SECURE_KERNEL */ + + /* Randomize high bits of ASLR slide */ + if (px_sa.psa_flags & _POSIX_SPAWN_HIGH_BITS_ASLR) { + imgp->ip_flags |= IMGPF_HIGH_BITS_ASLR; + } + + /* + * Forcibly disallow execution from data pages for the spawned process + * even if it would otherwise be permitted by the architecture default. + */ + if (px_sa.psa_flags & _POSIX_SPAWN_ALLOW_DATA_EXEC) { + imgp->ip_flags |= IMGPF_ALLOW_DATA_EXEC; + } + } + + /* + * Disable ASLR during image activation. This occurs either if the + * _POSIX_SPAWN_DISABLE_ASLR attribute was found above or if + * P_DISABLE_ASLR was inherited from the parent process. + */ + if (p->p_flag & P_DISABLE_ASLR) { + imgp->ip_flags |= IMGPF_DISABLE_ASLR; + } + + /* + * Clear transition flag so we won't hang if exec_activate_image() causes + * an automount (and launchd does a proc sysctl to service it). + * + * , . + */ + if (spawn_no_exec) { + proc_transend(p, 0); + proc_transit_set = 0; + } + +#if MAC_SPAWN /* XXX */ + if (uap->mac_p != USER_ADDR_NULL) { + error = mac_execve_enter(uap->mac_p, imgp); + if (error) { + goto bad; + } + } +#endif + + /* + * Activate the image + */ + error = exec_activate_image(imgp); + + if (error == 0 && !spawn_no_exec) { + p = proc_exec_switch_task(p, old_task, new_task, imgp->ip_new_thread); + /* proc ref returned */ + should_release_proc_ref = TRUE; + + /* + * Need to transfer pending watch port boosts to the new task while still making + * sure that the old task remains in the importance linkage. Create an importance + * linkage from old task to new task, then switch the task importance base + * of old task and new task. After the switch the port watch boost will be + * boosting the new task and new task will be donating importance to old task. + */ + inherit = ipc_importance_exec_switch_task(old_task, new_task); + } + + if (error == 0) { + /* process completed the exec */ + exec_done = TRUE; + } else if (error == -1) { + /* Image not claimed by any activator? */ + error = ENOEXEC; + } + + /* + * If we have a spawn attr, and it contains signal related flags, + * the we need to process them in the "context" of the new child + * process, so we have to process it following image activation, + * prior to making the thread runnable in user space. This is + * necessitated by some signal information being per-thread rather + * than per-process, and we don't have the new allocation in hand + * until after the image is activated. + */ + if (!error && imgp->ip_px_sa != NULL) { + thread_t child_thread = imgp->ip_new_thread; + uthread_t child_uthread = get_bsdthread_info(child_thread); + + /* + * Mask a list of signals, instead of them being unmasked, if + * they were unmasked in the parent; note that some signals + * are not maskable. + */ + if (px_sa.psa_flags & POSIX_SPAWN_SETSIGMASK) { + child_uthread->uu_sigmask = (px_sa.psa_sigmask & ~sigcantmask); + } + /* + * Default a list of signals instead of ignoring them, if + * they were ignored in the parent. Note that we pass + * spawn_no_exec to setsigvec() to indicate that we called + * fork1() and therefore do not need to call proc_signalstart() + * internally. + */ + if (px_sa.psa_flags & POSIX_SPAWN_SETSIGDEF) { + vec.sa_handler = SIG_DFL; + vec.sa_tramp = 0; + vec.sa_mask = 0; + vec.sa_flags = 0; + for (sig = 1; sig < NSIG; sig++) { + if (px_sa.psa_sigdefault & (1 << (sig - 1))) { + error = setsigvec(p, child_thread, sig, &vec, spawn_no_exec); + } + } + } + + /* + * Activate the CPU usage monitor, if requested. This is done via a task-wide, per-thread CPU + * usage limit, which will generate a resource exceeded exception if any one thread exceeds the + * limit. + * + * Userland gives us interval in seconds, and the kernel SPI expects nanoseconds. + */ + if (px_sa.psa_cpumonitor_percent != 0) { + /* + * Always treat a CPU monitor activation coming from spawn as entitled. Requiring + * an entitlement to configure the monitor a certain way seems silly, since + * whomever is turning it on could just as easily choose not to do so. + */ + error = proc_set_task_ruse_cpu(p->task, + TASK_POLICY_RESOURCE_ATTRIBUTE_NOTIFY_EXC, + px_sa.psa_cpumonitor_percent, + px_sa.psa_cpumonitor_interval * NSEC_PER_SEC, + 0, TRUE); + } + } + +bad: + + if (error == 0) { + /* reset delay idle sleep status if set */ +#if !CONFIG_EMBEDDED + if ((p->p_flag & P_DELAYIDLESLEEP) == P_DELAYIDLESLEEP) { + OSBitAndAtomic(~((uint32_t)P_DELAYIDLESLEEP), &p->p_flag); + } +#endif /* !CONFIG_EMBEDDED */ + /* upon successful spawn, re/set the proc control state */ + if (imgp->ip_px_sa != NULL) { + switch (px_sa.psa_pcontrol) { + case POSIX_SPAWN_PCONTROL_THROTTLE: + p->p_pcaction = P_PCTHROTTLE; + break; + case POSIX_SPAWN_PCONTROL_SUSPEND: + p->p_pcaction = P_PCSUSP; + break; + case POSIX_SPAWN_PCONTROL_KILL: + p->p_pcaction = P_PCKILL; + break; + case POSIX_SPAWN_PCONTROL_NONE: + default: + p->p_pcaction = 0; + break; + } + ; + } + exec_resettextvp(p, imgp); + +#if CONFIG_MEMORYSTATUS + /* Has jetsam attributes? */ + if (imgp->ip_px_sa != NULL && (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_SET)) { + /* + * With 2-level high-water-mark support, POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND is no + * longer relevant, as background limits are described via the inactive limit slots. + * + * That said, however, if the POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND is passed in, + * we attempt to mimic previous behavior by forcing the BG limit data into the + * inactive/non-fatal mode and force the active slots to hold system_wide/fatal mode. + */ + if (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_HIWATER_BACKGROUND) { + memorystatus_update(p, px_sa.psa_priority, 0, + (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_USE_EFFECTIVE_PRIORITY), + TRUE, + -1, TRUE, + px_sa.psa_memlimit_inactive, FALSE); + } else { + memorystatus_update(p, px_sa.psa_priority, 0, + (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_USE_EFFECTIVE_PRIORITY), + TRUE, + px_sa.psa_memlimit_active, + (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_MEMLIMIT_ACTIVE_FATAL), + px_sa.psa_memlimit_inactive, + (px_sa.psa_jetsam_flags & POSIX_SPAWN_JETSAM_MEMLIMIT_INACTIVE_FATAL)); + } + } +#endif /* CONFIG_MEMORYSTATUS */ + if (imgp->ip_px_sa != NULL && px_sa.psa_thread_limit > 0) { + task_set_thread_limit(new_task, (uint16_t)px_sa.psa_thread_limit); + } + } + + /* + * If we successfully called fork1(), we always need to do this; + * we identify this case by noting the IMGPF_SPAWN flag. This is + * because we come back from that call with signals blocked in the + * child, and we have to unblock them, but we want to wait until + * after we've performed any spawn actions. This has to happen + * before check_for_signature(), which uses psignal. + */ + if (spawn_no_exec) { + if (proc_transit_set) { + proc_transend(p, 0); + } + + /* + * Drop the signal lock on the child which was taken on our + * behalf by forkproc()/cloneproc() to prevent signals being + * received by the child in a partially constructed state. + */ + proc_signalend(p, 0); + + /* flag the 'fork' has occurred */ + proc_knote(p->p_pptr, NOTE_FORK | p->p_pid); + } + + /* flag exec has occurred, notify only if it has not failed due to FP Key error */ + if (!error && ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)) { + proc_knote(p, NOTE_EXEC); + } + + + if (error == 0) { + /* + * We need to initialize the bank context behind the protection of + * the proc_trans lock to prevent a race with exit. We can't do this during + * exec_activate_image because task_bank_init checks entitlements that + * aren't loaded until subsequent calls (including exec_resettextvp). + */ + error = proc_transstart(p, 0, 0); + + if (error == 0) { + task_bank_init(new_task); + proc_transend(p, 0); + } + +#if __arm64__ + proc_legacy_footprint(p, new_task, __FUNCTION__); +#endif /* __arm64__ */ + } + + /* Inherit task role from old task to new task for exec */ + if (error == 0 && !spawn_no_exec) { + proc_inherit_task_role(new_task, old_task); + } + + /* + * Apply the spawnattr policy, apptype (which primes the task for importance donation), + * and bind any portwatch ports to the new task. + * This must be done after the exec so that the child's thread is ready, + * and after the in transit state has been released, because priority is + * dropped here so we need to be prepared for a potentially long preemption interval + * + * TODO: Consider splitting this up into separate phases + */ + if (error == 0 && imgp->ip_px_sa != NULL) { + struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa; + + exec_handle_spawnattr_policy(p, psa->psa_apptype, psa->psa_qos_clamp, psa->psa_darwin_role, + portwatch_ports, portwatch_count); + } + + /* + * Apply the requested maximum address. + */ + if (error == 0 && imgp->ip_px_sa != NULL) { + struct _posix_spawnattr *psa = (struct _posix_spawnattr *) imgp->ip_px_sa; + + if (psa->psa_max_addr) { + vm_map_set_max_addr(get_task_map(new_task), psa->psa_max_addr); + } + } + + if (error == 0) { + /* Apply the main thread qos */ + thread_t main_thread = imgp->ip_new_thread; + task_set_main_thread_qos(new_task, main_thread); + +#if CONFIG_MACF + /* + * Processes with the MAP_JIT entitlement are permitted to have + * a jumbo-size map. + */ + if (mac_proc_check_map_anon(p, 0, 0, 0, MAP_JIT, NULL) == 0) { + vm_map_set_jumbo(get_task_map(new_task)); + } +#endif /* CONFIG_MACF */ + } + + /* + * Release any ports we kept around for binding to the new task + * We need to release the rights even if the posix_spawn has failed. + */ + if (portwatch_ports != NULL) { + for (int i = 0; i < portwatch_count; i++) { + ipc_port_t port = NULL; + if ((port = portwatch_ports[i]) != NULL) { + ipc_port_release_send(port); + } + } + FREE(portwatch_ports, M_TEMP); + portwatch_ports = NULL; + portwatch_count = 0; + } + + /* + * We have to delay operations which might throw a signal until after + * the signals have been unblocked; however, we want that to happen + * after exec_resettextvp() so that the textvp is correct when they + * fire. + */ + if (error == 0) { + error = check_for_signature(p, imgp); + + /* + * Pay for our earlier safety; deliver the delayed signals from + * the incomplete spawn process now that it's complete. + */ + if (imgp != NULL && spawn_no_exec && (p->p_lflag & P_LTRACED)) { + psignal_vfork(p, p->task, imgp->ip_new_thread, SIGTRAP); + } + + if (error == 0 && !spawn_no_exec) { + KDBG(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXEC), + p->p_pid); + } + } + + + if (imgp != NULL) { + if (imgp->ip_vp) { + vnode_put(imgp->ip_vp); + } + if (imgp->ip_scriptvp) { + vnode_put(imgp->ip_scriptvp); + } + if (imgp->ip_strings) { + execargs_free(imgp); + } + if (imgp->ip_px_sfa != NULL) { + FREE(imgp->ip_px_sfa, M_TEMP); + } + if (imgp->ip_px_spa != NULL) { + FREE(imgp->ip_px_spa, M_TEMP); + } +#if CONFIG_PERSONAS + if (imgp->ip_px_persona != NULL) { + FREE(imgp->ip_px_persona, M_TEMP); + } +#endif +#if CONFIG_MACF + if (imgp->ip_px_smpx != NULL) { + spawn_free_macpolicyinfo(imgp->ip_px_smpx); + } + if (imgp->ip_execlabelp) { + mac_cred_label_free(imgp->ip_execlabelp); + } + if (imgp->ip_scriptlabelp) { + mac_vnode_label_free(imgp->ip_scriptlabelp); + } + if (imgp->ip_cs_error != OS_REASON_NULL) { + os_reason_free(imgp->ip_cs_error); + imgp->ip_cs_error = OS_REASON_NULL; + } +#endif + } + +#if CONFIG_DTRACE + if (spawn_no_exec) { + /* + * In the original DTrace reference implementation, + * posix_spawn() was a libc routine that just + * did vfork(2) then exec(2). Thus the proc::: probes + * are very fork/exec oriented. The details of this + * in-kernel implementation of posix_spawn() is different + * (while producing the same process-observable effects) + * particularly w.r.t. errors, and which thread/process + * is constructing what on behalf of whom. + */ + if (error) { + DTRACE_PROC1(spawn__failure, int, error); + } else { + DTRACE_PROC(spawn__success); + /* + * Some DTrace scripts, e.g. newproc.d in + * /usr/bin, rely on the the 'exec-success' + * probe being fired in the child after the + * new process image has been constructed + * in order to determine the associated pid. + * + * So, even though the parent built the image + * here, for compatibility, mark the new thread + * so 'exec-success' fires on it as it leaves + * the kernel. + */ + dtrace_thread_didexec(imgp->ip_new_thread); + } + } else { + if (error) { + DTRACE_PROC1(exec__failure, int, error); + } else { + dtrace_thread_didexec(imgp->ip_new_thread); + } + } + + if ((dtrace_proc_waitfor_hook = dtrace_proc_waitfor_exec_ptr) != NULL) { + (*dtrace_proc_waitfor_hook)(p); + } +#endif + +#if CONFIG_AUDIT + if (!error && AUDIT_ENABLED() && p) { + /* Add the CDHash of the new process to the audit record */ + uint8_t *cdhash = cs_get_cdhash(p); + if (cdhash) { + AUDIT_ARG(data, cdhash, sizeof(uint8_t), CS_CDHASH_LEN); + } + } +#endif + + /* + * clear bsd_info from old task if it did exec. + */ + if (task_did_exec(old_task)) { + set_bsdtask_info(old_task, NULL); + } + + /* clear bsd_info from new task and terminate it if exec failed */ + if (new_task != NULL && task_is_exec_copy(new_task)) { + set_bsdtask_info(new_task, NULL); + task_terminate_internal(new_task); + } + + /* Return to both the parent and the child? */ + if (imgp != NULL && spawn_no_exec) { + /* + * If the parent wants the pid, copy it out + */ + if (pid != USER_ADDR_NULL) { + (void)suword(pid, p->p_pid); + } + retval[0] = error; + + /* + * If we had an error, perform an internal reap ; this is + * entirely safe, as we have a real process backing us. + */ + if (error) { + proc_list_lock(); + p->p_listflag |= P_LIST_DEADPARENT; + proc_list_unlock(); + proc_lock(p); + /* make sure no one else has killed it off... */ + if (p->p_stat != SZOMB && p->exit_thread == NULL) { + p->exit_thread = current_thread(); + proc_unlock(p); + exit1(p, 1, (int *)NULL); + } else { + /* someone is doing it for us; just skip it */ + proc_unlock(p); + } + } + } + + /* + * Do not terminate the current task, if proc_exec_switch_task did not + * switch the tasks, terminating the current task without the switch would + * result in loosing the SIGKILL status. + */ + if (task_did_exec(old_task)) { + /* Terminate the current task, since exec will start in new task */ + task_terminate_internal(old_task); + } + + /* Release the thread ref returned by fork_create_child/fork1 */ + if (imgp != NULL && imgp->ip_new_thread) { + /* wake up the new thread */ + task_clear_return_wait(get_threadtask(imgp->ip_new_thread)); + thread_deallocate(imgp->ip_new_thread); + imgp->ip_new_thread = NULL; + } + + /* Release the ref returned by fork_create_child/fork1 */ + if (new_task) { + task_deallocate(new_task); + new_task = NULL; + } + + if (should_release_proc_ref) { + proc_rele(p); + } + + if (bufp != NULL) { + FREE(bufp, M_TEMP); + } + + if (inherit != NULL) { + ipc_importance_release(inherit); + } + + return error; +} + +/* + * proc_exec_switch_task + * + * Parameters: p proc + * old_task task before exec + * new_task task after exec + * new_thread thread in new task + * + * Returns: proc. + * + * Note: The function will switch the task pointer of proc + * from old task to new task. The switch needs to happen + * after draining all proc refs and inside a proc translock. + * In the case of failure to switch the task, which might happen + * if the process received a SIGKILL or jetsam killed it, it will make + * sure that the new tasks terminates. User proc ref returned + * to caller. + * + * This function is called after point of no return, in the case + * failure to switch, it will terminate the new task and swallow the + * error and let the terminated process complete exec and die. + */ +proc_t +proc_exec_switch_task(proc_t p, task_t old_task, task_t new_task, thread_t new_thread) +{ + int error = 0; + boolean_t task_active; + boolean_t proc_active; + boolean_t thread_active; + thread_t old_thread = current_thread(); + + /* + * Switch the task pointer of proc to new task. + * Before switching the task, wait for proc_refdrain. + * After the switch happens, the proc can disappear, + * take a ref before it disappears. Waiting for + * proc_refdrain in exec will block all other threads + * trying to take a proc ref, boost the current thread + * to avoid priority inversion. + */ + thread_set_exec_promotion(old_thread); + p = proc_refdrain_with_refwait(p, TRUE); + /* extra proc ref returned to the caller */ + + assert(get_threadtask(new_thread) == new_task); + task_active = task_is_active(new_task); + + /* Take the proc_translock to change the task ptr */ + proc_lock(p); + proc_active = !(p->p_lflag & P_LEXIT); + + /* Check if the current thread is not aborted due to SIGKILL */ + thread_active = thread_is_active(old_thread); + + /* + * Do not switch the task if the new task or proc is already terminated + * as a result of error in exec past point of no return + */ + if (proc_active && task_active && thread_active) { + error = proc_transstart(p, 1, 0); + if (error == 0) { + uthread_t new_uthread = get_bsdthread_info(new_thread); + uthread_t old_uthread = get_bsdthread_info(current_thread()); + + /* + * bsd_info of old_task will get cleared in execve and posix_spawn + * after firing exec-success/error dtrace probe. + */ + p->task = new_task; + + /* Clear dispatchqueue and workloop ast offset */ + p->p_dispatchqueue_offset = 0; + p->p_dispatchqueue_serialno_offset = 0; + p->p_return_to_kernel_offset = 0; + + /* Copy the signal state, dtrace state and set bsd ast on new thread */ + act_set_astbsd(new_thread); + new_uthread->uu_siglist = old_uthread->uu_siglist; + new_uthread->uu_sigwait = old_uthread->uu_sigwait; + new_uthread->uu_sigmask = old_uthread->uu_sigmask; + new_uthread->uu_oldmask = old_uthread->uu_oldmask; + new_uthread->uu_vforkmask = old_uthread->uu_vforkmask; + new_uthread->uu_exit_reason = old_uthread->uu_exit_reason; +#if CONFIG_DTRACE + new_uthread->t_dtrace_sig = old_uthread->t_dtrace_sig; + new_uthread->t_dtrace_stop = old_uthread->t_dtrace_stop; + new_uthread->t_dtrace_resumepid = old_uthread->t_dtrace_resumepid; + assert(new_uthread->t_dtrace_scratch == NULL); + new_uthread->t_dtrace_scratch = old_uthread->t_dtrace_scratch; + + old_uthread->t_dtrace_sig = 0; + old_uthread->t_dtrace_stop = 0; + old_uthread->t_dtrace_resumepid = 0; + old_uthread->t_dtrace_scratch = NULL; +#endif + /* Copy the resource accounting info */ + thread_copy_resource_info(new_thread, current_thread()); + + /* Clear the exit reason and signal state on old thread */ + old_uthread->uu_exit_reason = NULL; + old_uthread->uu_siglist = 0; + + /* Add the new uthread to proc uthlist and remove the old one */ + TAILQ_INSERT_TAIL(&p->p_uthlist, new_uthread, uu_list); + TAILQ_REMOVE(&p->p_uthlist, old_uthread, uu_list); + + task_set_did_exec_flag(old_task); + task_clear_exec_copy_flag(new_task); + + task_copy_fields_for_exec(new_task, old_task); + + proc_transend(p, 1); + } + } + + proc_unlock(p); + proc_refwake(p); + thread_clear_exec_promotion(old_thread); + + if (error != 0 || !task_active || !proc_active || !thread_active) { + task_terminate_internal(new_task); + } + + return p; +} + +/* + * execve + * + * Parameters: uap->fname File name to exec + * uap->argp Argument list + * uap->envp Environment list + * + * Returns: 0 Success + * __mac_execve:EINVAL Invalid argument + * __mac_execve:ENOTSUP Invalid argument + * __mac_execve:EACCES Permission denied + * __mac_execve:EINTR Interrupted function + * __mac_execve:ENOMEM Not enough space + * __mac_execve:EFAULT Bad address + * __mac_execve:ENAMETOOLONG Filename too long + * __mac_execve:ENOEXEC Executable file format error + * __mac_execve:ETXTBSY Text file busy [misuse of error code] + * __mac_execve:??? + * + * TODO: Dynamic linker header address on stack is copied via suword() + */ +/* ARGSUSED */ +int +execve(proc_t p, struct execve_args *uap, int32_t *retval) +{ + struct __mac_execve_args muap; + int err; + + memoryshot(VM_EXECVE, DBG_FUNC_NONE); + + muap.fname = uap->fname; + muap.argp = uap->argp; + muap.envp = uap->envp; + muap.mac_p = USER_ADDR_NULL; + err = __mac_execve(p, &muap, retval); + + return err; +} + +/* + * __mac_execve + * + * Parameters: uap->fname File name to exec + * uap->argp Argument list + * uap->envp Environment list + * uap->mac_p MAC label supplied by caller + * + * Returns: 0 Success + * EINVAL Invalid argument + * ENOTSUP Not supported + * ENOEXEC Executable file format error + * exec_activate_image:EINVAL Invalid argument + * exec_activate_image:EACCES Permission denied + * exec_activate_image:EINTR Interrupted function + * exec_activate_image:ENOMEM Not enough space + * exec_activate_image:EFAULT Bad address + * exec_activate_image:ENAMETOOLONG Filename too long + * exec_activate_image:ENOEXEC Executable file format error + * exec_activate_image:ETXTBSY Text file busy [misuse of error code] + * exec_activate_image:EBADEXEC The executable is corrupt/unknown + * exec_activate_image:??? + * mac_execve_enter:??? + * + * TODO: Dynamic linker header address on stack is copied via suword() + */ +int +__mac_execve(proc_t p, struct __mac_execve_args *uap, int32_t *retval) +{ + char *bufp = NULL; + struct image_params *imgp; + struct vnode_attr *vap; + struct vnode_attr *origvap; + int error; + int is_64 = IS_64BIT_PROCESS(p); + struct vfs_context context; + struct uthread *uthread; + task_t old_task = current_task(); + task_t new_task = NULL; + boolean_t should_release_proc_ref = FALSE; + boolean_t exec_done = FALSE; + boolean_t in_vfexec = FALSE; + void *inherit = NULL; + + context.vc_thread = current_thread(); + context.vc_ucred = kauth_cred_proc_ref(p); /* XXX must NOT be kauth_cred_get() */ + + /* Allocate a big chunk for locals instead of using stack since these + * structures a pretty big. + */ + MALLOC(bufp, char *, (sizeof(*imgp) + sizeof(*vap) + sizeof(*origvap)), M_TEMP, M_WAITOK | M_ZERO); + imgp = (struct image_params *) bufp; + if (bufp == NULL) { + error = ENOMEM; + goto exit_with_error; + } + vap = (struct vnode_attr *) (bufp + sizeof(*imgp)); + origvap = (struct vnode_attr *) (bufp + sizeof(*imgp) + sizeof(*vap)); + + /* Initialize the common data in the image_params structure */ + imgp->ip_user_fname = uap->fname; + imgp->ip_user_argv = uap->argp; + imgp->ip_user_envv = uap->envp; + imgp->ip_vattr = vap; + imgp->ip_origvattr = origvap; + imgp->ip_vfs_context = &context; + imgp->ip_flags = (is_64 ? IMGPF_WAS_64BIT_ADDR : IMGPF_NONE) | ((p->p_flag & P_DISABLE_ASLR) ? IMGPF_DISABLE_ASLR : IMGPF_NONE); + imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); + imgp->ip_mac_return = 0; + imgp->ip_cs_error = OS_REASON_NULL; + +#if CONFIG_MACF + if (uap->mac_p != USER_ADDR_NULL) { + error = mac_execve_enter(uap->mac_p, imgp); + if (error) { + kauth_cred_unref(&context.vc_ucred); + goto exit_with_error; + } + } +#endif + uthread = get_bsdthread_info(current_thread()); + if (uthread->uu_flag & UT_VFORK) { + imgp->ip_flags |= IMGPF_VFORK_EXEC; + in_vfexec = TRUE; + } else { + imgp->ip_flags |= IMGPF_EXEC; + + /* + * For execve case, create a new task and thread + * which points to current_proc. The current_proc will point + * to the new task after image activation and proc ref drain. + * + * proc (current_proc) <----- old_task (current_task) + * ^ | ^ + * | | | + * | ---------------------------------- + * | + * --------- new_task (task marked as TF_EXEC_COPY) + * + * After image activation, the proc will point to the new task + * and would look like following. + * + * proc (current_proc) <----- old_task (current_task, marked as TPF_DID_EXEC) + * ^ | + * | | + * | ----------> new_task + * | | + * ----------------- + * + * During exec any transition from new_task -> proc is fine, but don't allow + * transition from proc->task, since it will modify old_task. + */ + imgp->ip_new_thread = fork_create_child(old_task, + NULL, + p, + FALSE, + p->p_flag & P_LP64, + task_get_64bit_data(old_task), + TRUE); + /* task and thread ref returned by fork_create_child */ + if (imgp->ip_new_thread == NULL) { + error = ENOMEM; + goto exit_with_error; + } + + new_task = get_threadtask(imgp->ip_new_thread); + context.vc_thread = imgp->ip_new_thread; + } + + error = exec_activate_image(imgp); + /* thread and task ref returned for vfexec case */ + + if (imgp->ip_new_thread != NULL) { + /* + * task reference might be returned by exec_activate_image + * for vfexec. + */ + new_task = get_threadtask(imgp->ip_new_thread); + } + + if (!error && !in_vfexec) { + p = proc_exec_switch_task(p, old_task, new_task, imgp->ip_new_thread); + /* proc ref returned */ + should_release_proc_ref = TRUE; + + /* + * Need to transfer pending watch port boosts to the new task while still making + * sure that the old task remains in the importance linkage. Create an importance + * linkage from old task to new task, then switch the task importance base + * of old task and new task. After the switch the port watch boost will be + * boosting the new task and new task will be donating importance to old task. + */ + inherit = ipc_importance_exec_switch_task(old_task, new_task); + } + + kauth_cred_unref(&context.vc_ucred); + + /* Image not claimed by any activator? */ + if (error == -1) { + error = ENOEXEC; + } + + if (!error) { + exec_done = TRUE; + assert(imgp->ip_new_thread != NULL); + + exec_resettextvp(p, imgp); + error = check_for_signature(p, imgp); + } + + /* flag exec has occurred, notify only if it has not failed due to FP Key error */ + if (exec_done && ((p->p_lflag & P_LTERM_DECRYPTFAIL) == 0)) { + proc_knote(p, NOTE_EXEC); + } + + if (imgp->ip_vp != NULLVP) { + vnode_put(imgp->ip_vp); + } + if (imgp->ip_scriptvp != NULLVP) { + vnode_put(imgp->ip_scriptvp); + } + if (imgp->ip_strings) { + execargs_free(imgp); + } +#if CONFIG_MACF + if (imgp->ip_execlabelp) { + mac_cred_label_free(imgp->ip_execlabelp); + } + if (imgp->ip_scriptlabelp) { + mac_vnode_label_free(imgp->ip_scriptlabelp); + } +#endif + if (imgp->ip_cs_error != OS_REASON_NULL) { + os_reason_free(imgp->ip_cs_error); + imgp->ip_cs_error = OS_REASON_NULL; + } + + if (!error) { + /* + * We need to initialize the bank context behind the protection of + * the proc_trans lock to prevent a race with exit. We can't do this during + * exec_activate_image because task_bank_init checks entitlements that + * aren't loaded until subsequent calls (including exec_resettextvp). + */ + error = proc_transstart(p, 0, 0); + } + + if (!error) { + task_bank_init(new_task); + proc_transend(p, 0); + +#if __arm64__ + proc_legacy_footprint(p, new_task, __FUNCTION__); +#endif /* __arm64__ */ + + /* Sever any extant thread affinity */ + thread_affinity_exec(current_thread()); + + /* Inherit task role from old task to new task for exec */ + if (!in_vfexec) { + proc_inherit_task_role(new_task, old_task); + } + + thread_t main_thread = imgp->ip_new_thread; + + task_set_main_thread_qos(new_task, main_thread); + +#if CONFIG_MACF + /* + * Processes with the MAP_JIT entitlement are permitted to have + * a jumbo-size map. + */ + if (mac_proc_check_map_anon(p, 0, 0, 0, MAP_JIT, NULL) == 0) { + vm_map_set_jumbo(get_task_map(new_task)); + } +#endif /* CONFIG_MACF */ + + if (vm_darkwake_mode == TRUE) { + /* + * This process is being launched when the system + * is in darkwake. So mark it specially. This will + * cause all its pages to be entered in the background Q. + */ + task_set_darkwake_mode(new_task, vm_darkwake_mode); + } + +#if CONFIG_DTRACE + dtrace_thread_didexec(imgp->ip_new_thread); + + if ((dtrace_proc_waitfor_hook = dtrace_proc_waitfor_exec_ptr) != NULL) { + (*dtrace_proc_waitfor_hook)(p); + } +#endif + +#if CONFIG_AUDIT + if (!error && AUDIT_ENABLED() && p) { + /* Add the CDHash of the new process to the audit record */ + uint8_t *cdhash = cs_get_cdhash(p); + if (cdhash) { + AUDIT_ARG(data, cdhash, sizeof(uint8_t), CS_CDHASH_LEN); + } + } +#endif + + if (in_vfexec) { + vfork_return(p, retval, p->p_pid); + } + } else { + DTRACE_PROC1(exec__failure, int, error); + } + +exit_with_error: + + /* + * clear bsd_info from old task if it did exec. + */ + if (task_did_exec(old_task)) { + set_bsdtask_info(old_task, NULL); + } + + /* clear bsd_info from new task and terminate it if exec failed */ + if (new_task != NULL && task_is_exec_copy(new_task)) { + set_bsdtask_info(new_task, NULL); + task_terminate_internal(new_task); + } + + if (imgp != NULL) { + /* + * Do not terminate the current task, if proc_exec_switch_task did not + * switch the tasks, terminating the current task without the switch would + * result in loosing the SIGKILL status. + */ + if (task_did_exec(old_task)) { + /* Terminate the current task, since exec will start in new task */ + task_terminate_internal(old_task); + } + + /* Release the thread ref returned by fork_create_child */ + if (imgp->ip_new_thread) { + /* wake up the new exec thread */ + task_clear_return_wait(get_threadtask(imgp->ip_new_thread)); + thread_deallocate(imgp->ip_new_thread); + imgp->ip_new_thread = NULL; + } + } + + /* Release the ref returned by fork_create_child */ + if (new_task) { + task_deallocate(new_task); + new_task = NULL; + } + + if (should_release_proc_ref) { + proc_rele(p); + } + + if (bufp != NULL) { + FREE(bufp, M_TEMP); + } + + if (inherit != NULL) { + ipc_importance_release(inherit); + } + + return error; +} + + +/* + * copyinptr + * + * Description: Copy a pointer in from user space to a user_addr_t in kernel + * space, based on 32/64 bitness of the user space + * + * Parameters: froma User space address + * toptr Address of kernel space user_addr_t + * ptr_size 4/8, based on 'froma' address space + * + * Returns: 0 Success + * EFAULT Bad 'froma' + * + * Implicit returns: + * *ptr_size Modified + */ +static int +copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size) +{ + int error; + + if (ptr_size == 4) { + /* 64 bit value containing 32 bit address */ + unsigned int i; + + error = copyin(froma, &i, 4); + *toptr = CAST_USER_ADDR_T(i); /* SAFE */ + } else { + error = copyin(froma, toptr, 8); + } + return error; +} + + +/* + * copyoutptr + * + * Description: Copy a pointer out from a user_addr_t in kernel space to + * user space, based on 32/64 bitness of the user space + * + * Parameters: ua User space address to copy to + * ptr Address of kernel space user_addr_t + * ptr_size 4/8, based on 'ua' address space + * + * Returns: 0 Success + * EFAULT Bad 'ua' + * + */ +static int +copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size) +{ + int error; + + if (ptr_size == 4) { + /* 64 bit value containing 32 bit address */ + unsigned int i = CAST_DOWN_EXPLICIT(unsigned int, ua); /* SAFE */ + + error = copyout(&i, ptr, 4); + } else { + error = copyout(&ua, ptr, 8); + } + return error; +} + + +/* + * exec_copyout_strings + * + * Copy out the strings segment to user space. The strings segment is put + * on a preinitialized stack frame. + * + * Parameters: struct image_params * the image parameter block + * int * a pointer to the stack offset variable + * + * Returns: 0 Success + * !0 Faiure: errno + * + * Implicit returns: + * (*stackp) The stack offset, modified + * + * Note: The strings segment layout is backward, from the beginning + * of the top of the stack to consume the minimal amount of + * space possible; the returned stack pointer points to the + * end of the area consumed (stacks grow downward). + * + * argc is an int; arg[i] are pointers; env[i] are pointers; + * the 0's are (void *)NULL's + * + * The stack frame layout is: + * + * +-------------+ <- p->user_stack + * | 16b | + * +-------------+ + * | STRING AREA | + * | : | + * | : | + * | : | + * +- -- -- -- --+ + * | PATH AREA | + * +-------------+ + * | 0 | + * +-------------+ + * | applev[n] | + * +-------------+ + * : + * : + * +-------------+ + * | applev[1] | + * +-------------+ + * | exec_path / | + * | applev[0] | + * +-------------+ + * | 0 | + * +-------------+ + * | env[n] | + * +-------------+ + * : + * : + * +-------------+ + * | env[0] | + * +-------------+ + * | 0 | + * +-------------+ + * | arg[argc-1] | + * +-------------+ + * : + * : + * +-------------+ + * | arg[0] | + * +-------------+ + * | argc | + * sp-> +-------------+ + * + * Although technically a part of the STRING AREA, we treat the PATH AREA as + * a separate entity. This allows us to align the beginning of the PATH AREA + * to a pointer boundary so that the exec_path, env[i], and argv[i] pointers + * which preceed it on the stack are properly aligned. + */ + +static int +exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp) +{ + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + int ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4; + int ptr_area_size; + void *ptr_buffer_start, *ptr_buffer; + int string_size; + + user_addr_t string_area; /* *argv[], *env[] */ + user_addr_t ptr_area; /* argv[], env[], applev[] */ + user_addr_t argc_area; /* argc */ + user_addr_t stack; + int error; + + unsigned i; + struct copyout_desc { + char *start_string; + int count; +#if CONFIG_DTRACE + user_addr_t *dtrace_cookie; +#endif + boolean_t null_term; + } descriptors[] = { + { + .start_string = imgp->ip_startargv, + .count = imgp->ip_argc, +#if CONFIG_DTRACE + .dtrace_cookie = &p->p_dtrace_argv, +#endif + .null_term = TRUE + }, + { + .start_string = imgp->ip_endargv, + .count = imgp->ip_envc, +#if CONFIG_DTRACE + .dtrace_cookie = &p->p_dtrace_envp, +#endif + .null_term = TRUE + }, + { + .start_string = imgp->ip_strings, + .count = 1, +#if CONFIG_DTRACE + .dtrace_cookie = NULL, +#endif + .null_term = FALSE + }, + { + .start_string = imgp->ip_endenvv, + .count = imgp->ip_applec - 1, /* exec_path handled above */ +#if CONFIG_DTRACE + .dtrace_cookie = NULL, +#endif + .null_term = TRUE + } + }; + + stack = *stackp; + + /* + * All previous contributors to the string area + * should have aligned their sub-area + */ + if (imgp->ip_strspace % ptr_size != 0) { + error = EINVAL; + goto bad; + } + + /* Grow the stack down for the strings we've been building up */ + string_size = imgp->ip_strendp - imgp->ip_strings; + stack -= string_size; + string_area = stack; + + /* + * Need room for one pointer for each string, plus + * one for the NULLs terminating the argv, envv, and apple areas. + */ + ptr_area_size = (imgp->ip_argc + imgp->ip_envc + imgp->ip_applec + 3) * ptr_size; + stack -= ptr_area_size; + ptr_area = stack; + + /* We'll construct all the pointer arrays in our string buffer, + * which we already know is aligned properly, and ip_argspace + * was used to verify we have enough space. + */ + ptr_buffer_start = ptr_buffer = (void *)imgp->ip_strendp; + + /* + * Need room for pointer-aligned argc slot. + */ + stack -= ptr_size; + argc_area = stack; + + /* + * Record the size of the arguments area so that sysctl_procargs() + * can return the argument area without having to parse the arguments. + */ + proc_lock(p); + p->p_argc = imgp->ip_argc; + p->p_argslen = (int)(*stackp - string_area); + proc_unlock(p); + + /* Return the initial stack address: the location of argc */ + *stackp = stack; + + /* + * Copy out the entire strings area. + */ + error = copyout(imgp->ip_strings, string_area, + string_size); + if (error) { + goto bad; + } + + for (i = 0; i < sizeof(descriptors) / sizeof(descriptors[0]); i++) { + char *cur_string = descriptors[i].start_string; + int j; + +#if CONFIG_DTRACE + if (descriptors[i].dtrace_cookie) { + proc_lock(p); + *descriptors[i].dtrace_cookie = ptr_area + ((uintptr_t)ptr_buffer - (uintptr_t)ptr_buffer_start); /* dtrace convenience */ + proc_unlock(p); + } +#endif /* CONFIG_DTRACE */ + + /* + * For each segment (argv, envv, applev), copy as many pointers as requested + * to our pointer buffer. + */ + for (j = 0; j < descriptors[i].count; j++) { + user_addr_t cur_address = string_area + (cur_string - imgp->ip_strings); + + /* Copy out the pointer to the current string. Alignment has been verified */ + if (ptr_size == 8) { + *(uint64_t *)ptr_buffer = (uint64_t)cur_address; + } else { + *(uint32_t *)ptr_buffer = (uint32_t)cur_address; + } + + ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size); + cur_string += strlen(cur_string) + 1; /* Only a NUL between strings in the same area */ + } + + if (descriptors[i].null_term) { + if (ptr_size == 8) { + *(uint64_t *)ptr_buffer = 0ULL; + } else { + *(uint32_t *)ptr_buffer = 0; + } + + ptr_buffer = (void *)((uintptr_t)ptr_buffer + ptr_size); + } + } + + /* + * Copy out all our pointer arrays in bulk. + */ + error = copyout(ptr_buffer_start, ptr_area, + ptr_area_size); + if (error) { + goto bad; + } + + /* argc (int32, stored in a ptr_size area) */ + error = copyoutptr((user_addr_t)imgp->ip_argc, argc_area, ptr_size); + if (error) { + goto bad; + } + +bad: + return error; +} + + +/* + * exec_extract_strings + * + * Copy arguments and environment from user space into work area; we may + * have already copied some early arguments into the work area, and if + * so, any arguments opied in are appended to those already there. + * This function is the primary manipulator of ip_argspace, since + * these are the arguments the client of execve(2) knows about. After + * each argv[]/envv[] string is copied, we charge the string length + * and argv[]/envv[] pointer slot to ip_argspace, so that we can + * full preflight the arg list size. + * + * Parameters: struct image_params * the image parameter block + * + * Returns: 0 Success + * !0 Failure: errno + * + * Implicit returns; + * (imgp->ip_argc) Count of arguments, updated + * (imgp->ip_envc) Count of environment strings, updated + * (imgp->ip_argspace) Count of remaining of NCARGS + * (imgp->ip_interp_buffer) Interpreter and args (mutated in place) + * + * + * Note: The argument and environment vectors are user space pointers + * to arrays of user space pointers. + */ +static int +exec_extract_strings(struct image_params *imgp) +{ + int error = 0; + int ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT_ADDR) ? 8 : 4; + int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4; + user_addr_t argv = imgp->ip_user_argv; + user_addr_t envv = imgp->ip_user_envv; + + /* + * Adjust space reserved for the path name by however much padding it + * needs. Doing this here since we didn't know if this would be a 32- + * or 64-bit process back in exec_save_path. + */ + while (imgp->ip_strspace % new_ptr_size != 0) { + *imgp->ip_strendp++ = '\0'; + imgp->ip_strspace--; + /* imgp->ip_argspace--; not counted towards exec args total */ + } + + /* + * From now on, we start attributing string space to ip_argspace + */ + imgp->ip_startargv = imgp->ip_strendp; + imgp->ip_argc = 0; + + if ((imgp->ip_flags & IMGPF_INTERPRET) != 0) { + user_addr_t arg; + char *argstart, *ch; + + /* First, the arguments in the "#!" string are tokenized and extracted. */ + argstart = imgp->ip_interp_buffer; + while (argstart) { + ch = argstart; + while (*ch && !IS_WHITESPACE(*ch)) { + ch++; + } + + if (*ch == '\0') { + /* last argument, no need to NUL-terminate */ + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE); + argstart = NULL; + } else { + /* NUL-terminate */ + *ch = '\0'; + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(argstart), UIO_SYSSPACE, TRUE); + + /* + * Find the next string. We know spaces at the end of the string have already + * been stripped. + */ + argstart = ch + 1; + while (IS_WHITESPACE(*argstart)) { + argstart++; + } + } + + /* Error-check, regardless of whether this is the last interpreter arg or not */ + if (error) { + goto bad; + } + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */ + imgp->ip_argc++; + } + + if (argv != 0LL) { + /* + * If we are running an interpreter, replace the av[0] that was + * passed to execve() with the path name that was + * passed to execve() for interpreters which do not use the PATH + * to locate their script arguments. + */ + error = copyinptr(argv, &arg, ptr_size); + if (error) { + goto bad; + } + if (arg != 0LL) { + argv += ptr_size; /* consume without using */ + } + } + + if (imgp->ip_interp_sugid_fd != -1) { + char temp[19]; /* "/dev/fd/" + 10 digits + NUL */ + snprintf(temp, sizeof(temp), "/dev/fd/%d", imgp->ip_interp_sugid_fd); + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(temp), UIO_SYSSPACE, TRUE); + } else { + error = exec_add_user_string(imgp, imgp->ip_user_fname, imgp->ip_seg, TRUE); + } + + if (error) { + goto bad; + } + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */ + imgp->ip_argc++; + } + + while (argv != 0LL) { + user_addr_t arg; + + error = copyinptr(argv, &arg, ptr_size); + if (error) { + goto bad; + } + + if (arg == 0LL) { + break; + } + + argv += ptr_size; + + /* + * av[n...] = arg[n] + */ + error = exec_add_user_string(imgp, arg, imgp->ip_seg, TRUE); + if (error) { + goto bad; + } + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; /* to hold argv[] entry */ + imgp->ip_argc++; + } + + /* Save space for argv[] NULL terminator */ + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; + + /* Note where the args ends and env begins. */ + imgp->ip_endargv = imgp->ip_strendp; + imgp->ip_envc = 0; + + /* Now, get the environment */ + while (envv != 0LL) { + user_addr_t env; + + error = copyinptr(envv, &env, ptr_size); + if (error) { + goto bad; + } + + envv += ptr_size; + if (env == 0LL) { + break; + } + /* + * av[n...] = env[n] + */ + error = exec_add_user_string(imgp, env, imgp->ip_seg, TRUE); + if (error) { + goto bad; + } + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; /* to hold envv[] entry */ + imgp->ip_envc++; + } + + /* Save space for envv[] NULL terminator */ + if (imgp->ip_argspace < new_ptr_size) { + error = E2BIG; + goto bad; + } + imgp->ip_argspace -= new_ptr_size; + + /* Align the tail of the combined argv+envv area */ + while (imgp->ip_strspace % new_ptr_size != 0) { + if (imgp->ip_argspace < 1) { + error = E2BIG; + goto bad; + } + *imgp->ip_strendp++ = '\0'; + imgp->ip_strspace--; + imgp->ip_argspace--; + } + + /* Note where the envv ends and applev begins. */ + imgp->ip_endenvv = imgp->ip_strendp; + + /* + * From now on, we are no longer charging argument + * space to ip_argspace. + */ + +bad: + return error; +} + +/* + * Libc has an 8-element array set up for stack guard values. It only fills + * in one of those entries, and both gcc and llvm seem to use only a single + * 8-byte guard. Until somebody needs more than an 8-byte guard value, don't + * do the work to construct them. + */ +#define GUARD_VALUES 1 +#define GUARD_KEY "stack_guard=" + +/* + * System malloc needs some entropy when it is initialized. + */ +#define ENTROPY_VALUES 2 +#define ENTROPY_KEY "malloc_entropy=" + +/* + * libplatform needs a random pointer-obfuscation value when it is initialized. + */ +#define PTR_MUNGE_VALUES 1 +#define PTR_MUNGE_KEY "ptr_munge=" + +/* + * System malloc engages nanozone for UIAPP. + */ +#define NANO_ENGAGE_KEY "MallocNanoZone=1" + +#define PFZ_KEY "pfz=" +extern user32_addr_t commpage_text32_location; +extern user64_addr_t commpage_text64_location; + +#define MAIN_STACK_VALUES 4 +#define MAIN_STACK_KEY "main_stack=" + +#define FSID_KEY "executable_file=" +#define DYLD_FSID_KEY "dyld_file=" +#define CDHASH_KEY "executable_cdhash=" + +#define FSID_MAX_STRING "0x1234567890abcdef,0x1234567890abcdef" + +#define HEX_STR_LEN 18 // 64-bit hex value "0x0123456701234567" + +static int +exec_add_entropy_key(struct image_params *imgp, + const char *key, + int values, + boolean_t embedNUL) +{ + const int limit = 8; + uint64_t entropy[limit]; + char str[strlen(key) + (HEX_STR_LEN + 1) * limit + 1]; + if (values > limit) { + values = limit; + } + + read_random(entropy, sizeof(entropy[0]) * values); + + if (embedNUL) { + entropy[0] &= ~(0xffull << 8); + } + + int len = snprintf(str, sizeof(str), "%s0x%llx", key, entropy[0]); + int remaining = sizeof(str) - len; + for (int i = 1; i < values && remaining > 0; ++i) { + int start = sizeof(str) - remaining; + len = snprintf(&str[start], remaining, ",0x%llx", entropy[i]); + remaining -= len; + } + + return exec_add_user_string(imgp, CAST_USER_ADDR_T(str), UIO_SYSSPACE, FALSE); +} + +/* + * Build up the contents of the apple[] string vector + */ +static int +exec_add_apple_strings(struct image_params *imgp, + const load_result_t *load_result) +{ + int error; + int img_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) ? 8 : 4; + + /* exec_save_path stored the first string */ + imgp->ip_applec = 1; + + /* adding the pfz string */ + { + char pfz_string[strlen(PFZ_KEY) + HEX_STR_LEN + 1]; + + if (img_ptr_size == 8) { + snprintf(pfz_string, sizeof(pfz_string), PFZ_KEY "0x%llx", commpage_text64_location); + } else { + snprintf(pfz_string, sizeof(pfz_string), PFZ_KEY "0x%x", commpage_text32_location); + } + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(pfz_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + + /* adding the NANO_ENGAGE_KEY key */ + if (imgp->ip_px_sa) { + int proc_flags = (((struct _posix_spawnattr *) imgp->ip_px_sa)->psa_flags); + + if ((proc_flags & _POSIX_SPAWN_NANO_ALLOCATOR) == _POSIX_SPAWN_NANO_ALLOCATOR) { + const char *nano_string = NANO_ENGAGE_KEY; + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(nano_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + } + + /* + * Supply libc with a collection of random values to use when + * implementing -fstack-protector. + * + * (The first random string always contains an embedded NUL so that + * __stack_chk_guard also protects against C string vulnerabilities) + */ + error = exec_add_entropy_key(imgp, GUARD_KEY, GUARD_VALUES, TRUE); + if (error) { + goto bad; + } + imgp->ip_applec++; + + /* + * Supply libc with entropy for system malloc. + */ + error = exec_add_entropy_key(imgp, ENTROPY_KEY, ENTROPY_VALUES, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + + /* + * Supply libpthread & libplatform with a random value to use for pointer + * obfuscation. + */ + error = exec_add_entropy_key(imgp, PTR_MUNGE_KEY, PTR_MUNGE_VALUES, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + + /* + * Add MAIN_STACK_KEY: Supplies the address and size of the main thread's + * stack if it was allocated by the kernel. + * + * The guard page is not included in this stack size as libpthread + * expects to add it back in after receiving this value. + */ + if (load_result->unixproc) { + char stack_string[strlen(MAIN_STACK_KEY) + (HEX_STR_LEN + 1) * MAIN_STACK_VALUES + 1]; + snprintf(stack_string, sizeof(stack_string), + MAIN_STACK_KEY "0x%llx,0x%llx,0x%llx,0x%llx", + (uint64_t)load_result->user_stack, + (uint64_t)load_result->user_stack_size, + (uint64_t)load_result->user_stack_alloc, + (uint64_t)load_result->user_stack_alloc_size); + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(stack_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + + if (imgp->ip_vattr) { + uint64_t fsid = vnode_get_va_fsid(imgp->ip_vattr); + uint64_t fsobjid = imgp->ip_vattr->va_fileid; + + char fsid_string[strlen(FSID_KEY) + strlen(FSID_MAX_STRING) + 1]; + snprintf(fsid_string, sizeof(fsid_string), + FSID_KEY "0x%llx,0x%llx", fsid, fsobjid); + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(fsid_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + + if (imgp->ip_dyld_fsid || imgp->ip_dyld_fsobjid) { + char fsid_string[strlen(DYLD_FSID_KEY) + strlen(FSID_MAX_STRING) + 1]; + snprintf(fsid_string, sizeof(fsid_string), + DYLD_FSID_KEY "0x%llx,0x%llx", imgp->ip_dyld_fsid, imgp->ip_dyld_fsobjid); + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(fsid_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + + uint8_t cdhash[SHA1_RESULTLEN]; + int cdhash_errror = ubc_cs_getcdhash(imgp->ip_vp, imgp->ip_arch_offset, cdhash); + if (cdhash_errror == 0) { + char hash_string[strlen(CDHASH_KEY) + 2 * SHA1_RESULTLEN + 1]; + strncpy(hash_string, CDHASH_KEY, sizeof(hash_string)); + char *p = hash_string + sizeof(CDHASH_KEY) - 1; + for (int i = 0; i < SHA1_RESULTLEN; i++) { + snprintf(p, 3, "%02x", (int) cdhash[i]); + p += 2; + } + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(hash_string), UIO_SYSSPACE, FALSE); + if (error) { + goto bad; + } + imgp->ip_applec++; + } + + /* Align the tail of the combined applev area */ + while (imgp->ip_strspace % img_ptr_size != 0) { + *imgp->ip_strendp++ = '\0'; + imgp->ip_strspace--; + } + +bad: + return error; +} + +#define unix_stack_size(p) (p->p_rlimit[RLIMIT_STACK].rlim_cur) + +/* + * exec_check_permissions + * + * Description: Verify that the file that is being attempted to be executed + * is in fact allowed to be executed based on it POSIX file + * permissions and other access control criteria + * + * Parameters: struct image_params * the image parameter block + * + * Returns: 0 Success + * EACCES Permission denied + * ENOEXEC Executable file format error + * ETXTBSY Text file busy [misuse of error code] + * vnode_getattr:??? + * vnode_authorize:??? + */ +static int +exec_check_permissions(struct image_params *imgp) +{ + struct vnode *vp = imgp->ip_vp; + struct vnode_attr *vap = imgp->ip_vattr; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + int error; + kauth_action_t action; + + /* Only allow execution of regular files */ + if (!vnode_isreg(vp)) { + return EACCES; + } + + /* Get the file attributes that we will be using here and elsewhere */ + VATTR_INIT(vap); + VATTR_WANTED(vap, va_uid); + VATTR_WANTED(vap, va_gid); + VATTR_WANTED(vap, va_mode); + VATTR_WANTED(vap, va_fsid); + VATTR_WANTED(vap, va_fsid64); + VATTR_WANTED(vap, va_fileid); + VATTR_WANTED(vap, va_data_size); + if ((error = vnode_getattr(vp, vap, imgp->ip_vfs_context)) != 0) { + return error; + } + + /* + * Ensure that at least one execute bit is on - otherwise root + * will always succeed, and we don't want to happen unless the + * file really is executable. + */ + if (!vfs_authopaque(vnode_mount(vp)) && ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)) { + return EACCES; + } + + /* Disallow zero length files */ + if (vap->va_data_size == 0) { + return ENOEXEC; + } + + imgp->ip_arch_offset = (user_size_t)0; + imgp->ip_arch_size = vap->va_data_size; + + /* Disable setuid-ness for traced programs or if MNT_NOSUID */ + if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_lflag & P_LTRACED)) { + vap->va_mode &= ~(VSUID | VSGID); + } + + /* + * Disable _POSIX_SPAWN_ALLOW_DATA_EXEC and _POSIX_SPAWN_DISABLE_ASLR + * flags for setuid/setgid binaries. + */ + if (vap->va_mode & (VSUID | VSGID)) { + imgp->ip_flags &= ~(IMGPF_ALLOW_DATA_EXEC | IMGPF_DISABLE_ASLR); + } + +#if CONFIG_MACF + error = mac_vnode_check_exec(imgp->ip_vfs_context, vp, imgp); + if (error) { + return error; + } +#endif + + /* Check for execute permission */ + action = KAUTH_VNODE_EXECUTE; + /* Traced images must also be readable */ + if (p->p_lflag & P_LTRACED) { + action |= KAUTH_VNODE_READ_DATA; + } + if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0) { + return error; + } + +#if 0 + /* Don't let it run if anyone had it open for writing */ + vnode_lock(vp); + if (vp->v_writecount) { + panic("going to return ETXTBSY %x", vp); + vnode_unlock(vp); + return ETXTBSY; + } + vnode_unlock(vp); +#endif + + + /* XXX May want to indicate to underlying FS that vnode is open */ + + return error; +} + + +/* + * exec_handle_sugid + * + * Initially clear the P_SUGID in the process flags; if an SUGID process is + * exec'ing a non-SUGID image, then this is the point of no return. + * + * If the image being activated is SUGID, then replace the credential with a + * copy, disable tracing (unless the tracing process is root), reset the + * mach task port to revoke it, set the P_SUGID bit, + * + * If the saved user and group ID will be changing, then make sure it happens + * to a new credential, rather than a shared one. + * + * Set the security token (this is probably obsolete, given that the token + * should not technically be separate from the credential itself). + * + * Parameters: struct image_params * the image parameter block + * + * Returns: void No failure indication + * + * Implicit returns: + * Potentially modified/replaced + * Potentially revoked + * P_SUGID bit potentially modified + * Potentially modified + */ +static int +exec_handle_sugid(struct image_params *imgp) +{ + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); + kauth_cred_t my_cred, my_new_cred; + int i; + int leave_sugid_clear = 0; + int mac_reset_ipc = 0; + int error = 0; + task_t task = NULL; +#if CONFIG_MACF + int mac_transition, disjoint_cred = 0; + int label_update_return = 0; + + /* + * Determine whether a call to update the MAC label will result in the + * credential changing. + * + * Note: MAC policies which do not actually end up modifying + * the label subsequently are strongly encouraged to + * return 0 for this check, since a non-zero answer will + * slow down the exec fast path for normal binaries. + */ + mac_transition = mac_cred_check_label_update_execve( + imgp->ip_vfs_context, + imgp->ip_vp, + imgp->ip_arch_offset, + imgp->ip_scriptvp, + imgp->ip_scriptlabelp, + imgp->ip_execlabelp, + p, + imgp->ip_px_smpx); +#endif + + OSBitAndAtomic(~((uint32_t)P_SUGID), &p->p_flag); + + /* + * Order of the following is important; group checks must go last, + * as we use the success of the 'ismember' check combined with the + * failure of the explicit match to indicate that we will be setting + * the egid of the process even though the new process did not + * require VSUID/VSGID bits in order for it to set the new group as + * its egid. + * + * Note: Technically, by this we are implying a call to + * setegid() in the new process, rather than implying + * it used its VSGID bit to set the effective group, + * even though there is no code in that process to make + * such a call. + */ + if (((imgp->ip_origvattr->va_mode & VSUID) != 0 && + kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) || + ((imgp->ip_origvattr->va_mode & VSGID) != 0 && + ((kauth_cred_ismember_gid(cred, imgp->ip_origvattr->va_gid, &leave_sugid_clear) || !leave_sugid_clear) || + (kauth_cred_getgid(cred) != imgp->ip_origvattr->va_gid)))) { +#if CONFIG_MACF +/* label for MAC transition and neither VSUID nor VSGID */ +handle_mac_transition: +#endif + +#if !SECURE_KERNEL + /* + * Replace the credential with a copy of itself if euid or + * egid change. + * + * Note: setuid binaries will automatically opt out of + * group resolver participation as a side effect + * of this operation. This is an intentional + * part of the security model, which requires a + * participating credential be established by + * escalating privilege, setting up all other + * aspects of the credential including whether + * or not to participate in external group + * membership resolution, then dropping their + * effective privilege to that of the desired + * final credential state. + * + * Modifications to p_ucred must be guarded using the + * proc's ucred lock. This prevents others from accessing + * a garbage credential. + */ + while (imgp->ip_origvattr->va_mode & VSUID) { + my_cred = kauth_cred_proc_ref(p); + my_new_cred = kauth_cred_setresuid(my_cred, KAUTH_UID_NONE, imgp->ip_origvattr->va_uid, imgp->ip_origvattr->va_uid, KAUTH_UID_NONE); + + if (my_new_cred == my_cred) { + kauth_cred_unref(&my_cred); + break; + } + + /* update cred on proc */ + proc_ucred_lock(p); + + if (p->p_ucred != my_cred) { + proc_ucred_unlock(p); + kauth_cred_unref(&my_new_cred); + continue; + } + + /* donate cred reference on my_new_cred to p->p_ucred */ + p->p_ucred = my_new_cred; + PROC_UPDATE_CREDS_ONPROC(p); + proc_ucred_unlock(p); + + /* drop additional reference that was taken on the previous cred */ + kauth_cred_unref(&my_cred); + + break; + } + + while (imgp->ip_origvattr->va_mode & VSGID) { + my_cred = kauth_cred_proc_ref(p); + my_new_cred = kauth_cred_setresgid(my_cred, KAUTH_GID_NONE, imgp->ip_origvattr->va_gid, imgp->ip_origvattr->va_gid); + + if (my_new_cred == my_cred) { + kauth_cred_unref(&my_cred); + break; + } + + /* update cred on proc */ + proc_ucred_lock(p); + + if (p->p_ucred != my_cred) { + proc_ucred_unlock(p); + kauth_cred_unref(&my_new_cred); + continue; + } + + /* donate cred reference on my_new_cred to p->p_ucred */ + p->p_ucred = my_new_cred; + PROC_UPDATE_CREDS_ONPROC(p); + proc_ucred_unlock(p); + + /* drop additional reference that was taken on the previous cred */ + kauth_cred_unref(&my_cred); + + break; + } +#endif /* !SECURE_KERNEL */ + +#if CONFIG_MACF + /* + * If a policy has indicated that it will transition the label, + * before making the call into the MAC policies, get a new + * duplicate credential, so they can modify it without + * modifying any others sharing it. + */ + if (mac_transition) { + /* + * This hook may generate upcalls that require + * importance donation from the kernel. + * (23925818) + */ + thread_t thread = current_thread(); + thread_enable_send_importance(thread, TRUE); + kauth_proc_label_update_execve(p, + imgp->ip_vfs_context, + imgp->ip_vp, + imgp->ip_arch_offset, + imgp->ip_scriptvp, + imgp->ip_scriptlabelp, + imgp->ip_execlabelp, + &imgp->ip_csflags, + imgp->ip_px_smpx, + &disjoint_cred, /* will be non zero if disjoint */ + &label_update_return); + thread_enable_send_importance(thread, FALSE); + + if (disjoint_cred) { + /* + * If updating the MAC label resulted in a + * disjoint credential, flag that we need to + * set the P_SUGID bit. This protects + * against debuggers being attached by an + * insufficiently privileged process onto the + * result of a transition to a more privileged + * credential. + */ + leave_sugid_clear = 0; + } + + imgp->ip_mac_return = label_update_return; + } + + mac_reset_ipc = mac_proc_check_inherit_ipc_ports(p, p->p_textvp, p->p_textoff, imgp->ip_vp, imgp->ip_arch_offset, imgp->ip_scriptvp); + +#endif /* CONFIG_MACF */ + + /* + * If 'leave_sugid_clear' is non-zero, then we passed the + * VSUID and MACF checks, and successfully determined that + * the previous cred was a member of the VSGID group, but + * that it was not the default at the time of the execve, + * and that the post-labelling credential was not disjoint. + * So we don't set the P_SUGID or reset mach ports and fds + * on the basis of simply running this code. + */ + if (mac_reset_ipc || !leave_sugid_clear) { + /* + * Have mach reset the task and thread ports. + * We don't want anyone who had the ports before + * a setuid exec to be able to access/control the + * task/thread after. + */ + ipc_task_reset((imgp->ip_new_thread != NULL) ? + get_threadtask(imgp->ip_new_thread) : p->task); + ipc_thread_reset((imgp->ip_new_thread != NULL) ? + imgp->ip_new_thread : current_thread()); + } + + if (!leave_sugid_clear) { + /* + * Flag the process as setuid. + */ + OSBitOrAtomic(P_SUGID, &p->p_flag); + + /* + * Radar 2261856; setuid security hole fix + * XXX For setuid processes, attempt to ensure that + * stdin, stdout, and stderr are already allocated. + * We do not want userland to accidentally allocate + * descriptors in this range which has implied meaning + * to libc. + */ + for (i = 0; i < 3; i++) { + if (p->p_fd->fd_ofiles[i] != NULL) { + continue; + } + + /* + * Do the kernel equivalent of + * + * if i == 0 + * (void) open("/dev/null", O_RDONLY); + * else + * (void) open("/dev/null", O_WRONLY); + */ + + struct fileproc *fp; + int indx; + int flag; + struct nameidata *ndp = NULL; + + if (i == 0) { + flag = FREAD; + } else { + flag = FWRITE; + } + + if ((error = falloc(p, + &fp, &indx, imgp->ip_vfs_context)) != 0) { + continue; + } + + MALLOC(ndp, struct nameidata *, sizeof(*ndp), M_TEMP, M_WAITOK | M_ZERO); + if (ndp == NULL) { + fp_free(p, indx, fp); + error = ENOMEM; + break; + } + + NDINIT(ndp, LOOKUP, OP_OPEN, FOLLOW, UIO_SYSSPACE, + CAST_USER_ADDR_T("/dev/null"), + imgp->ip_vfs_context); + + if ((error = vn_open(ndp, flag, 0)) != 0) { + fp_free(p, indx, fp); + FREE(ndp, M_TEMP); + break; + } + + struct fileglob *fg = fp->f_fglob; + + fg->fg_flag = flag; + fg->fg_ops = &vnops; + fg->fg_data = ndp->ni_vp; + + vnode_put(ndp->ni_vp); + + proc_fdlock(p); + procfdtbl_releasefd(p, indx, NULL); + fp_drop(p, indx, fp, 1); + proc_fdunlock(p); + + FREE(ndp, M_TEMP); + } + } + } +#if CONFIG_MACF + else { + /* + * We are here because we were told that the MAC label will + * be transitioned, and the binary is not VSUID or VSGID; to + * deal with this case, we could either duplicate a lot of + * code, or we can indicate we want to default the P_SUGID + * bit clear and jump back up. + */ + if (mac_transition) { + leave_sugid_clear = 1; + goto handle_mac_transition; + } + } + +#endif /* CONFIG_MACF */ /* - * We use (string_area - path_area) here rather than the more - * intuitive (imgp->ip_argv - imgp->ip_strings) because we are - * interested in the length of the PATH_AREA in user space, - * rather than the actual length of the execution path, since - * it includes alignment padding of the PATH_AREA + STRING_AREA - * to a ptr_size boundary. + * Implement the semantic where the effective user and group become + * the saved user and group in exec'ed programs. + * + * Modifications to p_ucred must be guarded using the + * proc's ucred lock. This prevents others from accessing + * a garbage credential. */ - strspace = SIZE_IMG_STRSPACE - (string_area - path_area); for (;;) { - if (stringc == imgp->ip_envc) { - /* argv[n] = NULL */ - (void)copyoutptr(0LL, ptr_area, ptr_size); - ptr_area += ptr_size; - } - if (--stringc < 0) + my_cred = kauth_cred_proc_ref(p); + my_new_cred = kauth_cred_setsvuidgid(my_cred, kauth_cred_getuid(my_cred), kauth_cred_getgid(my_cred)); + + if (my_new_cred == my_cred) { + kauth_cred_unref(&my_cred); break; + } - /* pointer: argv[n]/env[n] */ - (void)copyoutptr(string_area, ptr_area, ptr_size); + /* update cred on proc */ + proc_ucred_lock(p); - /* string : argv[n][]/env[n][] */ - do { - if (strspace <= 0) { - error = E2BIG; - break; - } - error = copyoutstr(argv, string_area, - (unsigned)strspace, - (size_t *)&len); - string_area += len; - argv += len; - strspace -= len; - } while (error == ENAMETOOLONG); - if (error == EFAULT || error == E2BIG) - break; /* bad stack - user's problem */ - ptr_area += ptr_size; + if (p->p_ucred != my_cred) { + proc_ucred_unlock(p); + kauth_cred_unref(&my_new_cred); + continue; + } + + /* donate cred reference on my_new_cred to p->p_ucred */ + p->p_ucred = my_new_cred; + PROC_UPDATE_CREDS_ONPROC(p); + proc_ucred_unlock(p); + + /* drop additional reference that was taken on the previous cred */ + kauth_cred_unref(&my_cred); + + break; } - /* env[n] = NULL */ - (void)copyoutptr(0LL, ptr_area, ptr_size); -bad: - return(error); + + /* Update the process' identity version and set the security token */ + p->p_idversion = OSIncrementAtomic(&nextpidversion); + + if (imgp->ip_new_thread != NULL) { + task = get_threadtask(imgp->ip_new_thread); + } else { + task = p->task; + } + set_security_token_task_internal(p, task); + + return error; } /* - * exec_extract_strings + * create_unix_stack * - * Copy arguments and environment from user space into work area; we may - * have already copied some early arguments into the work area, and if - * so, any arguments opied in are appended to those already there. + * Description: Set the user stack address for the process to the provided + * address. If a custom stack was not set as a result of the + * load process (i.e. as specified by the image file for the + * executable), then allocate the stack in the provided map and + * set up appropriate guard pages for enforcing administrative + * limits on stack growth, if they end up being needed. * - * Parameters: struct image_params * the image parameter block + * Parameters: p Process to set stack on + * load_result Information from mach-o load commands + * map Address map in which to allocate the new stack * - * Returns: 0 Success - * !0 Failure: errno + * Returns: KERN_SUCCESS Stack successfully created + * !KERN_SUCCESS Mach failure code + */ +static kern_return_t +create_unix_stack(vm_map_t map, load_result_t* load_result, + proc_t p) +{ + mach_vm_size_t size, prot_size; + mach_vm_offset_t addr, prot_addr; + kern_return_t kr; + + mach_vm_address_t user_stack = load_result->user_stack; + + proc_lock(p); + p->user_stack = user_stack; + if (load_result->custom_stack) { + p->p_lflag |= P_LCUSTOM_STACK; + } + proc_unlock(p); + + if (load_result->user_stack_alloc_size > 0) { + /* + * Allocate enough space for the maximum stack size we + * will ever authorize and an extra page to act as + * a guard page for stack overflows. For default stacks, + * vm_initial_limit_stack takes care of the extra guard page. + * Otherwise we must allocate it ourselves. + */ + if (mach_vm_round_page_overflow(load_result->user_stack_alloc_size, &size)) { + return KERN_INVALID_ARGUMENT; + } + addr = mach_vm_trunc_page(load_result->user_stack - size); + kr = mach_vm_allocate_kernel(map, &addr, size, + VM_FLAGS_FIXED, VM_MEMORY_STACK); + if (kr != KERN_SUCCESS) { + // Can't allocate at default location, try anywhere + addr = 0; + kr = mach_vm_allocate_kernel(map, &addr, size, + VM_FLAGS_ANYWHERE, VM_MEMORY_STACK); + if (kr != KERN_SUCCESS) { + return kr; + } + + user_stack = addr + size; + load_result->user_stack = user_stack; + + proc_lock(p); + p->user_stack = user_stack; + proc_unlock(p); + } + + load_result->user_stack_alloc = addr; + + /* + * And prevent access to what's above the current stack + * size limit for this process. + */ + if (load_result->user_stack_size == 0) { + proc_list_lock(); + load_result->user_stack_size = unix_stack_size(p); + proc_list_unlock(); + prot_size = mach_vm_trunc_page(size - load_result->user_stack_size); + } else { + prot_size = PAGE_SIZE; + } + + prot_addr = addr; + kr = mach_vm_protect(map, + prot_addr, + prot_size, + FALSE, + VM_PROT_NONE); + if (kr != KERN_SUCCESS) { + (void)mach_vm_deallocate(map, addr, size); + return kr; + } + } + + return KERN_SUCCESS; +} + +#include + +/* + * load_init_program_at_path * - * Implicit returns; - * (imgp->ip_argc) Count of arguments, updated - * (imgp->ip_envc) Count of environment strings, updated + * Description: Load the "init" program; in most cases, this will be "launchd" * + * Parameters: p Process to call execve() to create + * the "init" program + * scratch_addr Page in p, scratch space + * path NULL terminated path * - * Notes: The argument and environment vectors are user space pointers - * to arrays of user space pointers. + * Returns: KERN_SUCCESS Success + * !KERN_SUCCESS See execve/mac_execve for error codes + * + * Notes: The process that is passed in is the first manufactured + * process on the system, and gets here via bsd_ast() firing + * for the first time. This is done to ensure that bsd_init() + * has run to completion. + * + * The address map of the first manufactured process matches the + * word width of the kernel. Once the self-exec completes, the + * initproc might be different. */ static int -exec_extract_strings(struct image_params *imgp) +load_init_program_at_path(proc_t p, user_addr_t scratch_addr, const char* path) { - int error = 0; - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - int seg = (IS_64BIT_PROCESS(p) ? UIO_USERSPACE64 : UIO_USERSPACE32); - int ptr_size = (imgp->ip_flags & IMGPF_WAS_64BIT) ? 8 : 4; - user_addr_t argv = imgp->ip_user_argv; - user_addr_t envv = imgp->ip_user_envv; + int retval[2]; + int error; + struct execve_args init_exec_args; + user_addr_t argv0 = USER_ADDR_NULL, argv1 = USER_ADDR_NULL; - /* Now, get rest of arguments */ + /* + * Validate inputs and pre-conditions + */ + assert(p); + assert(scratch_addr); + assert(path); /* - * If we are running an interpreter, replace the av[0] that was - * passed to execve() with the fully qualified path name that was - * passed to execve() for interpreters which do not use the PATH - * to locate their script arguments. + * Copy out program name. */ - if((imgp->ip_flags & IMGPF_INTERPRET) != 0 && argv != 0LL) { - user_addr_t arg; + size_t path_length = strlen(path) + 1; + argv0 = scratch_addr; + error = copyout(path, argv0, path_length); + if (error) { + return error; + } - error = copyinptr(argv, &arg, ptr_size); - if (error) - goto bad; - if (arg != 0LL && arg != (user_addr_t)-1) { - argv += ptr_size; - error = exec_add_string(imgp, imgp->ip_user_fname, seg); - if (error) - goto bad; - imgp->ip_argc++; + scratch_addr = USER_ADDR_ALIGN(scratch_addr + path_length, sizeof(user_addr_t)); + + /* + * Put out first (and only) argument, similarly. + * Assumes everything fits in a page as allocated above. + */ + if (boothowto & RB_SINGLE) { + const char *init_args = "-s"; + size_t init_args_length = strlen(init_args) + 1; + + argv1 = scratch_addr; + error = copyout(init_args, argv1, init_args_length); + if (error) { + return error; } + + scratch_addr = USER_ADDR_ALIGN(scratch_addr + init_args_length, sizeof(user_addr_t)); } - while (argv != 0LL) { - user_addr_t arg; + if (proc_is64bit(p)) { + user64_addr_t argv64bit[3] = {}; - error = copyinptr(argv, &arg, ptr_size); - if (error) - goto bad; + argv64bit[0] = argv0; + argv64bit[1] = argv1; + argv64bit[2] = USER_ADDR_NULL; - argv += ptr_size; - if (arg == 0LL) { - break; - } else if (arg == (user_addr_t)-1) { - /* Um... why would it be -1? */ - error = EFAULT; - goto bad; + error = copyout(argv64bit, scratch_addr, sizeof(argv64bit)); + if (error) { + return error; } - /* - * av[n...] = arg[n] - */ - error = exec_add_string(imgp, arg, seg); - if (error) - goto bad; - imgp->ip_argc++; - } + } else { + user32_addr_t argv32bit[3] = {}; + + argv32bit[0] = (user32_addr_t)argv0; + argv32bit[1] = (user32_addr_t)argv1; + argv32bit[2] = USER_ADDR_NULL; + + error = copyout(argv32bit, scratch_addr, sizeof(argv32bit)); + if (error) { + return error; + } + } + + /* + * Set up argument block for fake call to execve. + */ + init_exec_args.fname = argv0; + init_exec_args.argp = scratch_addr; + init_exec_args.envp = USER_ADDR_NULL; + + /* + * So that init task is set with uid,gid 0 token + */ + set_security_token(p); + + return execve(p, &init_exec_args, retval); +} + +static const char * init_programs[] = { +#if DEBUG + "/usr/local/sbin/launchd.debug", +#endif +#if DEVELOPMENT || DEBUG + "/usr/local/sbin/launchd.development", +#endif + "/sbin/launchd", +}; + +/* + * load_init_program + * + * Description: Load the "init" program; in most cases, this will be "launchd" + * + * Parameters: p Process to call execve() to create + * the "init" program + * + * Returns: (void) + * + * Notes: The process that is passed in is the first manufactured + * process on the system, and gets here via bsd_ast() firing + * for the first time. This is done to ensure that bsd_init() + * has run to completion. + * + * In DEBUG & DEVELOPMENT builds, the launchdsuffix boot-arg + * may be used to select a specific launchd executable. As with + * the kcsuffix boot-arg, setting launchdsuffix to "" or "release" + * will force /sbin/launchd to be selected. + * + * Search order by build: + * + * DEBUG DEVELOPMENT RELEASE PATH + * ---------------------------------------------------------------------------------- + * 1 1 NA /usr/local/sbin/launchd.$LAUNCHDSUFFIX + * 2 NA NA /usr/local/sbin/launchd.debug + * 3 2 NA /usr/local/sbin/launchd.development + * 4 3 1 /sbin/launchd + */ +void +load_init_program(proc_t p) +{ + uint32_t i; + int error; + vm_map_t map = current_map(); + mach_vm_offset_t scratch_addr = 0; + mach_vm_size_t map_page_size = vm_map_page_size(map); + + (void) mach_vm_allocate_kernel(map, &scratch_addr, map_page_size, VM_FLAGS_ANYWHERE, VM_KERN_MEMORY_NONE); +#if CONFIG_MEMORYSTATUS + (void) memorystatus_init_at_boot_snapshot(); +#endif /* CONFIG_MEMORYSTATUS */ + +#if DEBUG || DEVELOPMENT + /* Check for boot-arg suffix first */ + char launchd_suffix[64]; + if (PE_parse_boot_argn("launchdsuffix", launchd_suffix, sizeof(launchd_suffix))) { + char launchd_path[128]; + boolean_t is_release_suffix = ((launchd_suffix[0] == 0) || + (strcmp(launchd_suffix, "release") == 0)); + + if (is_release_suffix) { + printf("load_init_program: attempting to load /sbin/launchd\n"); + error = load_init_program_at_path(p, (user_addr_t)scratch_addr, "/sbin/launchd"); + if (!error) { + return; + } + + panic("Process 1 exec of launchd.release failed, errno %d", error); + } else { + strlcpy(launchd_path, "/usr/local/sbin/launchd.", sizeof(launchd_path)); + strlcat(launchd_path, launchd_suffix, sizeof(launchd_path)); + + printf("load_init_program: attempting to load %s\n", launchd_path); + error = load_init_program_at_path(p, (user_addr_t)scratch_addr, launchd_path); + if (!error) { + return; + } else { + printf("load_init_program: failed loading %s: errno %d\n", launchd_path, error); + } + } + } +#endif + + error = ENOENT; + for (i = 0; i < sizeof(init_programs) / sizeof(init_programs[0]); i++) { + printf("load_init_program: attempting to load %s\n", init_programs[i]); + error = load_init_program_at_path(p, (user_addr_t)scratch_addr, init_programs[i]); + if (!error) { + return; + } else { + printf("load_init_program: failed loading %s: errno %d\n", init_programs[i], error); + } + } + + panic("Process 1 exec of %s failed, errno %d", ((i == 0) ? "" : init_programs[i - 1]), error); +} + +/* + * load_return_to_errno + * + * Description: Convert a load_return_t (Mach error) to an errno (BSD error) + * + * Parameters: lrtn Mach error number + * + * Returns: (int) BSD error number + * 0 Success + * EBADARCH Bad architecture + * EBADMACHO Bad Mach object file + * ESHLIBVERS Bad shared library version + * ENOMEM Out of memory/resource shortage + * EACCES Access denied + * ENOENT Entry not found (usually "file does + * does not exist") + * EIO An I/O error occurred + * EBADEXEC The executable is corrupt/unknown + */ +static int +load_return_to_errno(load_return_t lrtn) +{ + switch (lrtn) { + case LOAD_SUCCESS: + return 0; + case LOAD_BADARCH: + case LOAD_BADARCH_X86: + return EBADARCH; + case LOAD_BADMACHO: + case LOAD_BADMACHO_UPX: + return EBADMACHO; + case LOAD_SHLIB: + return ESHLIBVERS; + case LOAD_NOSPACE: + case LOAD_RESOURCE: + return ENOMEM; + case LOAD_PROTECT: + return EACCES; + case LOAD_ENOENT: + return ENOENT; + case LOAD_IOERROR: + return EIO; + case LOAD_FAILURE: + case LOAD_DECRYPTFAIL: + default: + return EBADEXEC; + } +} + +#include +#include +#include +#include +#include +#include + +/* + * execargs_alloc + * + * Description: Allocate the block of memory used by the execve arguments. + * At the same time, we allocate a page so that we can read in + * the first page of the image. + * + * Parameters: struct image_params * the image parameter block + * + * Returns: 0 Success + * EINVAL Invalid argument + * EACCES Permission denied + * EINTR Interrupted function + * ENOMEM Not enough space + * + * Notes: This is a temporary allocation into the kernel address space + * to enable us to copy arguments in from user space. This is + * necessitated by not mapping the process calling execve() into + * the kernel address space during the execve() system call. + * + * We assemble the argument and environment, etc., into this + * region before copying it as a single block into the child + * process address space (at the top or bottom of the stack, + * depending on which way the stack grows; see the function + * exec_copyout_strings() for details). + * + * This ends up with a second (possibly unnecessary) copy compared + * with assembing the data directly into the child address space, + * instead, but since we cannot be guaranteed that the parent has + * not modified its environment, we can't really know that it's + * really a block there as well. + */ + - /* Now, get the environment */ - while (envv != 0LL) { - user_addr_t env; +static int execargs_waiters = 0; +lck_mtx_t *execargs_cache_lock; - error = copyinptr(envv, &env, ptr_size); - if (error) - goto bad; +static void +execargs_lock_lock(void) +{ + lck_mtx_lock_spin(execargs_cache_lock); +} - envv += ptr_size; - if (env == 0LL) { - break; - } else if (env == (user_addr_t)-1) { - error = EFAULT; - goto bad; - } - /* - * av[n...] = env[n] - */ - error = exec_add_string(imgp, env, seg); - if (error) - goto bad; - imgp->ip_envc++; - } -bad: - return error; +static void +execargs_lock_unlock(void) +{ + lck_mtx_unlock(execargs_cache_lock); } +static wait_result_t +execargs_lock_sleep(void) +{ + return lck_mtx_sleep(execargs_cache_lock, LCK_SLEEP_DEFAULT, &execargs_free_count, THREAD_INTERRUPTIBLE); +} -#define unix_stack_size(p) (p->p_rlimit[RLIMIT_STACK].rlim_cur) +static kern_return_t +execargs_purgeable_allocate(char **execarg_address) +{ + kern_return_t kr = vm_allocate_kernel(bsd_pageable_map, (vm_offset_t *)execarg_address, BSD_PAGEABLE_SIZE_PER_EXEC, VM_FLAGS_ANYWHERE | VM_FLAGS_PURGABLE, VM_KERN_MEMORY_NONE); + assert(kr == KERN_SUCCESS); + return kr; +} -static int -exec_check_permissions(struct image_params *imgp) +static kern_return_t +execargs_purgeable_reference(void *execarg_address) { - struct vnode *vp = imgp->ip_vp; - struct vnode_attr *vap = imgp->ip_vattr; - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - int error; - kauth_action_t action; + int state = VM_PURGABLE_NONVOLATILE; + kern_return_t kr = vm_purgable_control(bsd_pageable_map, (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state); - /* Only allow execution of regular files */ - if (!vnode_isreg(vp)) - return (EACCES); - - /* Get the file attributes that we will be using here and elsewhere */ - VATTR_INIT(vap); - VATTR_WANTED(vap, va_uid); - VATTR_WANTED(vap, va_gid); - VATTR_WANTED(vap, va_mode); - VATTR_WANTED(vap, va_fsid); - VATTR_WANTED(vap, va_fileid); - VATTR_WANTED(vap, va_data_size); - if ((error = vnode_getattr(vp, vap, imgp->ip_vfs_context)) != 0) - return (error); + assert(kr == KERN_SUCCESS); + return kr; +} - /* - * Ensure that at least one execute bit is on - otherwise root - * will always succeed, and we don't want to happen unless the - * file really is executable. - */ - if ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0) - return (EACCES); +static kern_return_t +execargs_purgeable_volatilize(void *execarg_address) +{ + int state = VM_PURGABLE_VOLATILE | VM_PURGABLE_ORDERING_OBSOLETE; + kern_return_t kr; + kr = vm_purgable_control(bsd_pageable_map, (vm_offset_t) execarg_address, VM_PURGABLE_SET_STATE, &state); - /* Disallow zero length files */ - if (vap->va_data_size == 0) - return (ENOEXEC); + assert(kr == KERN_SUCCESS); - imgp->ip_arch_offset = (user_size_t)0; - imgp->ip_arch_size = vap->va_data_size; + return kr; +} - /* Disable setuid-ness for traced programs or if MNT_NOSUID */ - if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_flag & P_TRACED)) - vap->va_mode &= ~(VSUID | VSGID); +static void +execargs_wakeup_waiters(void) +{ + thread_wakeup(&execargs_free_count); +} + +static int +execargs_alloc(struct image_params *imgp) +{ + kern_return_t kret; + wait_result_t res; + int i, cache_index = -1; + + execargs_lock_lock(); + + while (execargs_free_count == 0) { + execargs_waiters++; + res = execargs_lock_sleep(); + execargs_waiters--; + if (res != THREAD_AWAKENED) { + execargs_lock_unlock(); + return EINTR; + } + } - /* Check for execute permission */ - action = KAUTH_VNODE_EXECUTE; - /* Traced images must also be readable */ - if (p->p_flag & P_TRACED) - action |= KAUTH_VNODE_READ_DATA; - if ((error = vnode_authorize(vp, NULL, action, imgp->ip_vfs_context)) != 0) - return (error); + execargs_free_count--; - /* Don't let it run if anyone had it open for writing */ - if (vp->v_writecount) - return (ETXTBSY); + for (i = 0; i < execargs_cache_size; i++) { + vm_offset_t element = execargs_cache[i]; + if (element) { + cache_index = i; + imgp->ip_strings = (char *)(execargs_cache[i]); + execargs_cache[i] = 0; + break; + } + } + assert(execargs_free_count >= 0); - /* XXX May want to indicate to underlying FS that vnode is open */ + execargs_lock_unlock(); + + if (cache_index == -1) { + kret = execargs_purgeable_allocate(&imgp->ip_strings); + } else { + kret = execargs_purgeable_reference(imgp->ip_strings); + } + + assert(kret == KERN_SUCCESS); + if (kret != KERN_SUCCESS) { + return ENOMEM; + } + + /* last page used to read in file headers */ + imgp->ip_vdata = imgp->ip_strings + (NCARGS + PAGE_SIZE); + imgp->ip_strendp = imgp->ip_strings; + imgp->ip_argspace = NCARGS; + imgp->ip_strspace = (NCARGS + PAGE_SIZE); - return (error); + return 0; } /* - * exec_handle_sugid - * - * Initially clear the P_SUGID in the process flags; if an SUGID process is - * exec'ing a non-SUGID image, then this is the point of no return. - * - * If the image being activated is SUGI, then replace the credential with a - * copy, disable tracing (unless the tracing process is root), reset the - * mach task port to revoke it, set the P_SUGID bit, - * - * If the saved user and group ID will be changing, then make sure it happens - * to a new credential, rather than a shared one. + * execargs_free * - * Set the security token (this is probably obsolete, given that the token - * should not technically be separate from the credential itself). + * Description: Free the block of memory used by the execve arguments and the + * first page of the executable by a previous call to the function + * execargs_alloc(). * * Parameters: struct image_params * the image parameter block * - * Returns: void No failure indication - * - * Implicit returns: - * Potentially modified/replaced - * Potentially revoked - * P_SUGID bit potentially modified - * Potentially modified + * Returns: 0 Success + * EINVAL Invalid argument + * EINTR Oeration interrupted */ static int -exec_handle_sugid(struct image_params *imgp) +execargs_free(struct image_params *imgp) { - kauth_cred_t cred = vfs_context_ucred(imgp->ip_vfs_context); - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); - int i; - int error = 0; - static struct vnode *dev_null = NULLVP; - - p->p_flag &= ~P_SUGID; - - if (((imgp->ip_origvattr->va_mode & VSUID) != 0 && - kauth_cred_getuid(cred) != imgp->ip_origvattr->va_uid) || - ((imgp->ip_origvattr->va_mode & VSGID) != 0 && - cred->cr_gid != imgp->ip_origvattr->va_gid)) { -#if KTRACE - /* - * If process is being ktraced, turn off - unless - * root set it. - */ - if (p->p_tracep && !(p->p_traceflag & KTRFAC_ROOT)) { - struct vnode *tvp = p->p_tracep; - p->p_tracep = NULL; - p->p_traceflag = 0; - vnode_rele(tvp); - } -#endif - /* - * Replace the credential with a copy of itself if euid or egid change. - */ - if (imgp->ip_origvattr->va_mode & VSUID) { - p->p_ucred = kauth_cred_seteuid(p->p_ucred, imgp->ip_origvattr->va_uid); - } - if (imgp->ip_origvattr->va_mode & VSGID) { - p->p_ucred = kauth_cred_setegid(p->p_ucred, imgp->ip_origvattr->va_gid); - } - - /* - * Have mach reset the task and thread ports. - * We don't want anyone who had the ports before - * a setuid exec to be able to access/control the - * task/thread after. - */ - if (current_task() == p->task) { - ipc_task_reset(p->task); - ipc_thread_reset(current_thread()); - } - - p->p_flag |= P_SUGID; + kern_return_t kret; + int i; + boolean_t needs_wakeup = FALSE; - /* Cache the vnode for /dev/null the first time around */ - if (dev_null == NULLVP) { - struct nameidata nd1; + kret = execargs_purgeable_volatilize(imgp->ip_strings); - NDINIT(&nd1, LOOKUP, FOLLOW, UIO_SYSSPACE32, - CAST_USER_ADDR_T("/dev/null"), - imgp->ip_vfs_context); + execargs_lock_lock(); + execargs_free_count++; - if ((error = vn_open(&nd1, FREAD, 0)) == 0) { - dev_null = nd1.ni_vp; - /* - * vn_open returns with both a use_count - * and an io_count on the found vnode - * drop the io_count, but keep the use_count - */ - vnode_put(nd1.ni_vp); - } + for (i = 0; i < execargs_cache_size; i++) { + vm_offset_t element = execargs_cache[i]; + if (element == 0) { + execargs_cache[i] = (vm_offset_t) imgp->ip_strings; + imgp->ip_strings = NULL; + break; } + } - /* Radar 2261856; setuid security hole fix */ - /* Patch from OpenBSD: A. Ramesh */ - /* - * XXX For setuid processes, attempt to ensure that - * stdin, stdout, and stderr are already allocated. - * We do not want userland to accidentally allocate - * descriptors in this range which has implied meaning - * to libc. - */ - if (dev_null != NULLVP) { - for (i = 0; i < 3; i++) { - struct fileproc *fp; - int indx; - - if (p->p_fd->fd_ofiles[i] != NULL) - continue; + assert(imgp->ip_strings == NULL); - if ((error = falloc(p, &fp, &indx)) != 0) - continue; + if (execargs_waiters > 0) { + needs_wakeup = TRUE; + } - if ((error = vnode_ref_ext(dev_null, FREAD)) != 0) { - fp_free(p, indx, fp); - break; - } + execargs_lock_unlock(); - fp->f_fglob->fg_flag = FREAD; - fp->f_fglob->fg_type = DTYPE_VNODE; - fp->f_fglob->fg_ops = &vnops; - fp->f_fglob->fg_data = (caddr_t)dev_null; - - proc_fdlock(p); - procfdtbl_releasefd(p, indx, NULL); - fp_drop(p, indx, fp, 1); - proc_fdunlock(p); - } - /* - * for now we need to drop the reference immediately - * since we don't have any mechanism in place to - * release it before starting to unmount "/dev" - * during a reboot/shutdown - */ - vnode_rele(dev_null); - dev_null = NULLVP; - } + if (needs_wakeup == TRUE) { + execargs_wakeup_waiters(); } - /* - * Implement the semantic where the effective user and group become - * the saved user and group in exec'ed programs. - */ - p->p_ucred = kauth_cred_setsvuidgid(p->p_ucred, kauth_cred_getuid(p->p_ucred), p->p_ucred->cr_gid); - - /* XXX Obsolete; security token should not be separate from cred */ - set_security_token(p); - - return(error); + return kret == KERN_SUCCESS ? 0 : EINVAL; } -static kern_return_t -create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack, - struct proc *p) +static void +exec_resettextvp(proc_t p, struct image_params *imgp) { - mach_vm_size_t size; - mach_vm_offset_t addr; - - p->user_stack = user_stack; - if (!customstack) { - size = mach_vm_round_page(unix_stack_size(p)); - addr = mach_vm_trunc_page(user_stack - size); - return (mach_vm_allocate(map, &addr, size, - VM_MAKE_TAG(VM_MEMORY_STACK) | - VM_FLAGS_FIXED)); - } else - return(KERN_SUCCESS); -} + vnode_t vp; + off_t offset; + vnode_t tvp = p->p_textvp; + int ret; -#include + vp = imgp->ip_vp; + offset = imgp->ip_arch_offset; -static char init_program_name[128] = "/sbin/launchd"; -static const char * other_init = "/sbin/mach_init"; + if (vp == NULLVP) { + panic("exec_resettextvp: expected valid vp"); + } -char init_args[128] = ""; + ret = vnode_ref(vp); + proc_lock(p); + if (ret == 0) { + p->p_textvp = vp; + p->p_textoff = offset; + } else { + p->p_textvp = NULLVP; /* this is paranoia */ + p->p_textoff = 0; + } + proc_unlock(p); -struct execve_args init_exec_args; -int init_attempts = 0; + if (tvp != NULLVP) { + if (vnode_getwithref(tvp) == 0) { + vnode_rele(tvp); + vnode_put(tvp); + } + } +} +// Includes the 0-byte (therefore "SIZE" instead of "LEN"). +static const size_t CS_CDHASH_STRING_SIZE = CS_CDHASH_LEN * 2 + 1; -void -load_init_program(struct proc *p) +static void +cdhash_to_string(char str[CS_CDHASH_STRING_SIZE], uint8_t const * const cdhash) { - vm_offset_t init_addr; - char *argv[3]; - int error; - register_t retval[2]; - - error = 0; + static char const nibble[] = "0123456789abcdef"; - /* init_args are copied in string form directly from bootstrap */ - - do { - if (boothowto & RB_INITNAME) { - printf("init program? "); -#if FIXME /* [ */ - gets(init_program_name, init_program_name); -#endif /* FIXME ] */ - } + /* Apparently still the safest way to get a hex representation + * of binary data. + * xnu's printf routines have %*D/%20D in theory, but "not really", see: + * confusion around %*D/%nD in printf + */ + for (int i = 0; i < CS_CDHASH_LEN; ++i) { + str[i * 2] = nibble[(cdhash[i] & 0xf0) >> 4]; + str[i * 2 + 1] = nibble[cdhash[i] & 0x0f]; + } + str[CS_CDHASH_STRING_SIZE - 1] = 0; +} - if (error && ((boothowto & RB_INITNAME) == 0) && - (init_attempts == 1)) { - printf("Load of %s, errno %d, trying %s\n", - init_program_name, error, other_init); - error = 0; - bcopy(other_init, init_program_name, - sizeof(other_init)); - } +/* + * __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__ + * + * Description: Waits for the userspace daemon to respond to the request + * we made. Function declared non inline to be visible in + * stackshots and spindumps as well as debugging. + */ +__attribute__((noinline)) int +__EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(mach_port_t task_access_port, int32_t new_pid) +{ + return find_code_signature(task_access_port, new_pid); +} - init_attempts++; +static int +check_for_signature(proc_t p, struct image_params *imgp) +{ + mach_port_t port = NULL; + kern_return_t kr = KERN_FAILURE; + int error = EACCES; + boolean_t unexpected_failure = FALSE; + struct cs_blob *csb; + boolean_t require_success = FALSE; + int spawn = (imgp->ip_flags & IMGPF_SPAWN); + int vfexec = (imgp->ip_flags & IMGPF_VFORK_EXEC); + os_reason_t signature_failure_reason = OS_REASON_NULL; - if (error) { - printf("Load of %s failed, errno %d\n", - init_program_name, error); - error = 0; - boothowto |= RB_INITNAME; - continue; - } + /* + * Override inherited code signing flags with the + * ones for the process that is being successfully + * loaded + */ + proc_lock(p); + p->p_csflags = imgp->ip_csflags; + proc_unlock(p); - /* - * Copy out program name. - */ + /* Set the switch_protect flag on the map */ + if (p->p_csflags & (CS_HARD | CS_KILL)) { + vm_map_switch_protect(get_task_map(p->task), TRUE); + } - init_addr = VM_MIN_ADDRESS; - (void) vm_allocate(current_map(), &init_addr, - PAGE_SIZE, VM_FLAGS_ANYWHERE); - if (init_addr == 0) - init_addr++; + /* + * image activation may be failed due to policy + * which is unexpected but security framework does not + * approve of exec, kill and return immediately. + */ + if (imgp->ip_mac_return != 0) { + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY, 0, 0); + signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_SECURITY_POLICY); + error = imgp->ip_mac_return; + unexpected_failure = TRUE; + goto done; + } - (void) copyout((caddr_t) init_program_name, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(init_program_name)+1); + if (imgp->ip_cs_error != OS_REASON_NULL) { + signature_failure_reason = imgp->ip_cs_error; + imgp->ip_cs_error = OS_REASON_NULL; + error = EACCES; + goto done; + } - argv[0] = (char *) init_addr; - init_addr += sizeof(init_program_name); - init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); + /* If the code signature came through the image activation path, we skip the + * taskgated / externally attached path. */ + if (imgp->ip_csflags & CS_SIGNED) { + error = 0; + goto done; + } - /* - * Put out first (and only) argument, similarly. - * Assumes everything fits in a page as allocated - * above. - */ + /* The rest of the code is for signatures that either already have been externally + * attached (likely, but not necessarily by a previous run through the taskgated + * path), or that will now be attached by taskgated. */ + + kr = task_get_task_access_port(p->task, &port); + if (KERN_SUCCESS != kr || !IPC_PORT_VALID(port)) { + error = 0; + if (require_success) { + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASK_ACCESS_PORT, 0, 0); + signature_failure_reason = os_reason_create(OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASK_ACCESS_PORT); + error = EACCES; + } + goto done; + } - (void) copyout((caddr_t) init_args, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(init_args)); + /* + * taskgated returns KERN_SUCCESS if it has completed its work + * and the exec should continue, KERN_FAILURE if the exec should + * fail, or it may error out with different error code in an + * event of mig failure (e.g. process was signalled during the + * rpc call, taskgated died, mig server died etc.). + */ - argv[1] = (char *) init_addr; - init_addr += sizeof(init_args); - init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); + kr = __EXEC_WAITING_ON_TASKGATED_CODE_SIGNATURE_UPCALL__(port, p->p_pid); + switch (kr) { + case KERN_SUCCESS: + error = 0; + break; + case KERN_FAILURE: + error = EACCES; - /* - * Null-end the argument list - */ + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASKGATED_INVALID_SIG, 0, 0); + signature_failure_reason = os_reason_create(OS_REASON_CODESIGNING, CODESIGNING_EXIT_REASON_TASKGATED_INVALID_SIG); + goto done; + default: + error = EACCES; - argv[2] = (char *) 0; - - /* - * Copy out the argument list. - */ - - (void) copyout((caddr_t) argv, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(argv)); + KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_EXITREASON_CREATE) | DBG_FUNC_NONE, + p->p_pid, OS_REASON_EXEC, EXEC_EXIT_REASON_TASKGATED_OTHER, 0, 0); + signature_failure_reason = os_reason_create(OS_REASON_EXEC, EXEC_EXIT_REASON_TASKGATED_OTHER); + unexpected_failure = TRUE; + goto done; + } - /* - * Set up argument block for fake call to execve. - */ + /* Only do this if exec_resettextvp() did not fail */ + if (p->p_textvp != NULLVP) { + csb = ubc_cs_blob_get(p->p_textvp, -1, p->p_textoff); + + if (csb != NULL) { + /* As the enforcement we can do here is very limited, we only allow things that + * are the only reason why this code path still exists: + * Adhoc signed non-platform binaries without special cs_flags and without any + * entitlements (unrestricted ones still pass AMFI). */ + if ( + /* Revalidate the blob if necessary through bumped generation count. */ + (ubc_cs_generation_check(p->p_textvp) == 0 || + ubc_cs_blob_revalidate(p->p_textvp, csb, imgp, 0) == 0) && + /* Only CS_ADHOC, no CS_KILL, CS_HARD etc. */ + (csb->csb_flags & CS_ALLOWED_MACHO) == CS_ADHOC && + /* If it has a CMS blob, it's not adhoc. The CS_ADHOC flag can lie. */ + csblob_find_blob_bytes((const uint8_t *)csb->csb_mem_kaddr, csb->csb_mem_size, + CSSLOT_SIGNATURESLOT, + CSMAGIC_BLOBWRAPPER) == NULL && + /* It could still be in a trust cache (unlikely with CS_ADHOC), or a magic path. */ + csb->csb_platform_binary == 0 && + /* No entitlements, not even unrestricted ones. */ + csb->csb_entitlements_blob == NULL) { + proc_lock(p); + p->p_csflags |= CS_SIGNED | CS_VALID; + proc_unlock(p); + } else { + uint8_t cdhash[CS_CDHASH_LEN]; + char cdhash_string[CS_CDHASH_STRING_SIZE]; + proc_getcdhash(p, cdhash); + cdhash_to_string(cdhash_string, cdhash); + printf("ignoring detached code signature on '%s' with cdhash '%s' " + "because it is invalid, or not a simple adhoc signature.\n", + p->p_name, cdhash_string); + } + } + } - init_exec_args.fname = CAST_USER_ADDR_T(argv[0]); - init_exec_args.argp = CAST_USER_ADDR_T((char **)init_addr); - init_exec_args.envp = CAST_USER_ADDR_T(0); - - /* So that mach_init task - * is set with uid,gid 0 token - */ - set_security_token(p); +done: + if (0 == error) { + /* The process's code signature related properties are + * fully set up, so this is an opportune moment to log + * platform binary execution, if desired. */ + if (platform_exec_logging != 0 && csproc_get_platform_binary(p)) { + uint8_t cdhash[CS_CDHASH_LEN]; + char cdhash_string[CS_CDHASH_STRING_SIZE]; + proc_getcdhash(p, cdhash); + cdhash_to_string(cdhash_string, cdhash); + + os_log(peLog, "CS Platform Exec Logging: Executing platform signed binary " + "'%s' with cdhash %s\n", p->p_name, cdhash_string); + } + } else { + if (!unexpected_failure) { + p->p_csflags |= CS_KILLED; + } + /* make very sure execution fails */ + if (vfexec || spawn) { + assert(signature_failure_reason != OS_REASON_NULL); + psignal_vfork_with_reason(p, p->task, imgp->ip_new_thread, + SIGKILL, signature_failure_reason); + signature_failure_reason = OS_REASON_NULL; + error = 0; + } else { + assert(signature_failure_reason != OS_REASON_NULL); + psignal_with_reason(p, SIGKILL, signature_failure_reason); + signature_failure_reason = OS_REASON_NULL; + } + } - error = execve(p,&init_exec_args,retval); - } while (error); + /* If we hit this, we likely would have leaked an exit reason */ + assert(signature_failure_reason == OS_REASON_NULL); + return error; } /* - * Convert a load_return_t to an errno. + * Typically as soon as we start executing this process, the + * first instruction will trigger a VM fault to bring the text + * pages (as executable) into the address space, followed soon + * thereafter by dyld data structures (for dynamic executable). + * To optimize this, as well as improve support for hardware + * debuggers that can only access resident pages present + * in the process' page tables, we prefault some pages if + * possible. Errors are non-fatal. */ -static int -load_return_to_errno(load_return_t lrtn) +static void +exec_prefault_data(proc_t p __unused, struct image_params *imgp, load_result_t *load_result) { - switch (lrtn) { - case LOAD_SUCCESS: - return 0; - case LOAD_BADARCH: - return EBADARCH; - case LOAD_BADMACHO: - return EBADMACHO; - case LOAD_SHLIB: - return ESHLIBVERS; - case LOAD_NOSPACE: - case LOAD_RESOURCE: - return ENOMEM; - case LOAD_PROTECT: - return EACCES; - case LOAD_ENOENT: - return ENOENT; - case LOAD_IOERROR: - return EIO; - case LOAD_FAILURE: - default: - return EBADEXEC; + int ret; + size_t expected_all_image_infos_size; + + /* + * Prefault executable or dyld entry point. + */ + vm_fault(current_map(), + vm_map_trunc_page(load_result->entry_point, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_EXECUTE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + + if (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) { + expected_all_image_infos_size = sizeof(struct user64_dyld_all_image_infos); + } else { + expected_all_image_infos_size = sizeof(struct user32_dyld_all_image_infos); } -} -#include -#include -#include -#include -#include -#include + /* Decode dyld anchor structure from */ + if (load_result->dynlinker && + load_result->all_image_info_addr && + load_result->all_image_info_size >= expected_all_image_infos_size) { + union { + struct user64_dyld_all_image_infos infos64; + struct user32_dyld_all_image_infos infos32; + } all_image_infos; -extern semaphore_t execve_semaphore; + /* + * Pre-fault to avoid copyin() going through the trap handler + * and recovery path. + */ + vm_fault(current_map(), + vm_map_trunc_page(load_result->all_image_info_addr, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_WRITE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + if ((load_result->all_image_info_addr & PAGE_MASK) + expected_all_image_infos_size > PAGE_SIZE) { + /* all_image_infos straddles a page */ + vm_fault(current_map(), + vm_map_trunc_page(load_result->all_image_info_addr + expected_all_image_infos_size - 1, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_WRITE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + } -/* - * The block of memory used by the execve arguments. At the same time, - * we allocate a page so that we can read in the first page of the image. - */ -static int -execargs_alloc(struct image_params *imgp) -{ - kern_return_t kret; + ret = copyin(load_result->all_image_info_addr, + &all_image_infos, + expected_all_image_infos_size); + if (ret == 0 && all_image_infos.infos32.version >= DYLD_ALL_IMAGE_INFOS_ADDRESS_MINIMUM_VERSION) { + user_addr_t notification_address; + user_addr_t dyld_image_address; + user_addr_t dyld_version_address; + user_addr_t dyld_all_image_infos_address; + user_addr_t dyld_slide_amount; + + if (imgp->ip_flags & IMGPF_IS_64BIT_ADDR) { + notification_address = all_image_infos.infos64.notification; + dyld_image_address = all_image_infos.infos64.dyldImageLoadAddress; + dyld_version_address = all_image_infos.infos64.dyldVersion; + dyld_all_image_infos_address = all_image_infos.infos64.dyldAllImageInfosAddress; + } else { + notification_address = all_image_infos.infos32.notification; + dyld_image_address = all_image_infos.infos32.dyldImageLoadAddress; + dyld_version_address = all_image_infos.infos32.dyldVersion; + dyld_all_image_infos_address = all_image_infos.infos32.dyldAllImageInfosAddress; + } - kret = semaphore_wait(execve_semaphore); - if (kret != KERN_SUCCESS) - switch (kret) { - default: - return (EINVAL); - case KERN_INVALID_ADDRESS: - case KERN_PROTECTION_FAILURE: - return (EACCES); - case KERN_ABORTED: - case KERN_OPERATION_TIMED_OUT: - return (EINTR); - } + /* + * dyld statically sets up the all_image_infos in its Mach-O + * binary at static link time, with pointers relative to its default + * load address. Since ASLR might slide dyld before its first + * instruction is executed, "dyld_slide_amount" tells us how far + * dyld was loaded compared to its default expected load address. + * All other pointers into dyld's image should be adjusted by this + * amount. At some point later, dyld will fix up pointers to take + * into account the slide, at which point the all_image_infos_address + * field in the structure will match the runtime load address, and + * "dyld_slide_amount" will be 0, if we were to consult it again. + */ - kret = kmem_alloc_pageable(bsd_pageable_map, (vm_offset_t *)&imgp->ip_strings, NCARGS + PAGE_SIZE); - imgp->ip_vdata = imgp->ip_strings + NCARGS; - if (kret != KERN_SUCCESS) { - semaphore_signal(execve_semaphore); - return (ENOMEM); - } - return (0); -} + dyld_slide_amount = load_result->all_image_info_addr - dyld_all_image_infos_address; -static int -execargs_free(struct image_params *imgp) -{ - kern_return_t kret; +#if 0 + kprintf("exec_prefault: 0x%016llx 0x%08x 0x%016llx 0x%016llx 0x%016llx 0x%016llx\n", + (uint64_t)load_result->all_image_info_addr, + all_image_infos.infos32.version, + (uint64_t)notification_address, + (uint64_t)dyld_image_address, + (uint64_t)dyld_version_address, + (uint64_t)dyld_all_image_infos_address); +#endif - kmem_free(bsd_pageable_map, (vm_offset_t)imgp->ip_strings, NCARGS + PAGE_SIZE); - imgp->ip_strings = NULL; - - kret = semaphore_signal(execve_semaphore); - switch (kret) { - case KERN_INVALID_ADDRESS: - case KERN_PROTECTION_FAILURE: - return (EINVAL); - case KERN_ABORTED: - case KERN_OPERATION_TIMED_OUT: - return (EINTR); - case KERN_SUCCESS: - return(0); - default: - return (EINVAL); + vm_fault(current_map(), + vm_map_trunc_page(notification_address + dyld_slide_amount, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_EXECUTE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + vm_fault(current_map(), + vm_map_trunc_page(dyld_image_address + dyld_slide_amount, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_EXECUTE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + vm_fault(current_map(), + vm_map_trunc_page(dyld_version_address + dyld_slide_amount, + vm_map_page_mask(current_map())), + VM_PROT_READ, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + vm_fault(current_map(), + vm_map_trunc_page(dyld_all_image_infos_address + dyld_slide_amount, + vm_map_page_mask(current_map())), + VM_PROT_READ | VM_PROT_WRITE, + FALSE, VM_KERN_MEMORY_NONE, + THREAD_UNINT, NULL, 0); + } } }