X-Git-Url: https://git.saurik.com/apple/xnu.git/blobdiff_plain/6601e61aa18bf4f09af135ff61fc7f4771d23b06..13f56ec4e58bf8687e2a68032c093c0213dd519b:/bsd/kern/kern_exec.c diff --git a/bsd/kern/kern_exec.c b/bsd/kern/kern_exec.c index 29d2bd13f..4c17cd232 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. + * Copyright (c) 2000-2011 Apple Inc. All rights reserved. * - * @APPLE_LICENSE_HEADER_START@ + * @APPLE_OSREFERENCE_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 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. * - * This Original Code and all software distributed under the License are - * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER + * 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. + * 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_LICENSE_HEADER_END@ + * @APPLE_OSREFERENCE_LICENSE_HEADER_END@ */ /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */ /* @@ -68,6 +74,12 @@ * * 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 @@ -91,24 +103,58 @@ #include #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 /* thread_wakeup() */ +#include +#include + +#if CONFIG_MACF +#include +#include +#endif + #include #include -#include +#include #include -#include -#include + +#include + +#if CONFIG_DTRACE +/* Do not include dtrace.h, it redefines kmem_[alloc/free] */ +extern void (*dtrace_fasttrap_exec_ptr)(proc_t); +extern void (*dtrace_helpers_cleanup)(proc_t); +extern void dtrace_lazy_dofs_destroy(proc_t); + +#include +#endif + +/* support for child creation in exec after vfork */ +thread_t fork_create_child(task_t parent_task, proc_t child_proc, int inherit_memory, int is64bit); +void vfork_exit(proc_t p, int rv); +int setsigvec(proc_t, thread_t, int, struct __kern_sigaction *, boolean_t in_sigstart); +extern void proc_apply_task_networkbg_internal(proc_t); /* * Mach things for which prototypes are unavailable from Mach headers @@ -117,6 +163,12 @@ 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); extern struct savearea *get_user_regs(thread_t); @@ -125,69 +177,66 @@ extern struct savearea *get_user_regs(thread_t); #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 10 -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; #define ROUND_PTR(type, addr) \ - (type *)( ( (unsigned)(addr) + 16 - 1) \ + (type *)( ( (uintptr_t)(addr) + 16 - 1) \ & ~(16 - 1) ) 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); 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, ""); +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, user_addr_t user_stack, - int customstack, struct proc *p); + int customstack, proc_t p); static int copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size); +static void exec_resettextvp(proc_t, struct image_params *); +static int check_for_signature(proc_t, struct image_params *); -/* 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; - +/* We don't want this one exported */ +__private_extern__ +int open1(vfs_context_t, struct nameidata *, int, struct vnode_attr *, int32_t *); /* - * 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() @@ -195,29 +244,41 @@ 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; - - do { - size_t len = 0; - if (imgp->ip_strspace <= 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; + + if (space <= 0) { error = E2BIG; break; } - if (IS_UIO_SYS_SPACE(seg)) { + + if (!UIO_SEG_IS_USER_SPACE(seg)) { char *kstr = CAST_DOWN(char *,str); /* SAFE */ - error = copystr(kstr, imgp->ip_strendp, imgp->ip_strspace, &len); + error = copystr(kstr, imgp->ip_strendp, space, &len); } else { - error = copyinstr(str, imgp->ip_strendp, imgp->ip_strspace, - &len); + 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; } @@ -227,23 +288,26 @@ exec_add_string(struct image_params *imgp, user_addr_t str, /*uio_seg*/int seg) * 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 @@ -253,23 +317,21 @@ 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) { int error; size_t len; - char *kpath = CAST_DOWN(char *,path); /* SAFE */ - - imgp->ip_strendp = imgp->ip_strings; - imgp->ip_strspace = SIZE_IMG_STRSPACE; + char *kpath; 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); break; - case UIO_SYSSPACE32: + case UIO_SYSSPACE: + kpath = CAST_DOWN(char *,path); /* SAFE */ error = copystr(kpath, imgp->ip_strings, len, &len); break; default: @@ -280,12 +342,126 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg) if (!error) { imgp->ip_strendp += len; imgp->ip_strspace -= len; - imgp->ip_argv = imgp->ip_strendp; } 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); +} + +#ifdef IMGPF_POWERPC +/* + * exec_powerpc32_imgact + * + * Implicitly invoke the PowerPC handler for a byte-swapped image magic + * number. This may happen either as a result of an attempt to invoke a + * PowerPC image directly, or indirectly as the interpreter used in an + * interpreter script. + * + * Parameters; struct image_params * image parameter block + * + * Returns: -1 not an PowerPC image (keep looking) + * -3 Success: exec_archhandler_ppc: relookup + * >0 Failure: exec_archhandler_ppc: error number + * + * Note: This image activator does not handle the case of a direct + * invocation of the exec_archhandler_ppc, since in that case, the + * exec_archhandler_ppc itself is not a PowerPC binary; instead, + * binary image activators must recognize the exec_archhandler_ppc; + * This is managed in exec_check_permissions(). + * + * Note: This image activator is limited to 32 bit powerpc images; + * if support for 64 bit powerpc images is desired, it would + * be more in line with this design to write a separate 64 bit + * image activator. + */ +static int +exec_powerpc32_imgact(struct image_params *imgp) +{ + struct mach_header *mach_header = (struct mach_header *)imgp->ip_vdata; + int error; + size_t len = 0; + + /* + * Make sure it's a PowerPC binary. If we've already redirected + * from an interpreted file once, don't do it again. + */ + if (mach_header->magic != MH_CIGAM) { + /* + * If it's a cross-architecture 64 bit binary, then claim + * it, but refuse to run it. + */ + if (mach_header->magic == MH_CIGAM_64) + return (EBADARCH); + return (-1); + } + + /* If there is no exec_archhandler_ppc, we can't run it */ + if (exec_archhandler_ppc.path[0] == 0) + return (EBADARCH); + + /* Remember the type of the original file for later grading */ + if (!imgp->ip_origcputype) { + imgp->ip_origcputype = + OSSwapBigToHostInt32(mach_header->cputype); + imgp->ip_origcpusubtype = + OSSwapBigToHostInt32(mach_header->cpusubtype); + } + + /* + * The PowerPC flag will be set by the exec_check_permissions() + * call anyway; however, we set this flag here so that the relookup + * in execve() does not follow symbolic links, as a side effect. + */ + imgp->ip_flags |= IMGPF_POWERPC; + + /* impute an interpreter */ + error = copystr(exec_archhandler_ppc.path, imgp->ip_interp_buffer, + IMG_SHSIZE, &len); + if (error) + return (error); + + exec_reset_save_path(imgp); + exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_buffer), + UIO_SYSSPACE); + + /* + * provide a replacement string for p->p_comm; we have to use an + * alternate buffer for this, rather than replacing it directly, + * since the exec may fail and return to the parent. In that case, + * we would have erroneously changed the parent p->p_comm instead. + */ + strlcpy(imgp->ip_p_comm, imgp->ip_ndp->ni_cnd.cn_nameptr, MAXCOMLEN+1); + /* +1 to allow MAXCOMLEN characters to be copied */ + + return (-3); +} +#endif /* IMGPF_POWERPC */ /* @@ -293,7 +469,7 @@ exec_save_path(struct image_params *imgp, user_addr_t path, /*uio_seg*/int seg) * * 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 + * not already executing in PowerPC 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 @@ -314,15 +490,19 @@ exec_shell_imgact(struct image_params *imgp) { char *vdata = imgp->ip_vdata; char *ihp; - char *line_endp; + char *line_startp, *line_endp; char *interp; + proc_t p; + struct fileproc *fp; + int fd; + int error; /* * 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 + * Note: We disallow PowerPC, since the expectation is that we + * may run a PowerPC interpreter, but not an interpret a PowerPC * image. This is consistent with historical behaviour. */ if (vdata[0] != '#' || @@ -331,66 +511,112 @@ exec_shell_imgact(struct image_params *imgp) return (-1); } +#ifdef IMGPF_POWERPC + if ((imgp->ip_flags & IMGPF_POWERPC) != 0) + return (EBADARCH); +#endif /* IMGPF_POWERPC */ 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); } - /* Find the nominal end of the interpreter line */ - for( ihp = &vdata[2]; *ihp != '\n' && *ihp != '#'; ihp++) { - if (ihp >= &vdata[IMG_SHSIZE]) + /* 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_endp = ihp; - ihp = &vdata[2]; - /* Skip over leading spaces - until the interpreter name */ - while ( ihp < line_endp && ((*ihp == ' ') || (*ihp == '\t'))) - ihp++; + line_startp = ihp; - /* - * Find the last non-whitespace character before the end of line or - * the beginning of a comment; this is our new end of line. - */ - for (;line_endp > ihp && ((*line_endp == ' ') || (*line_endp == '\t')); line_endp--) - continue; + /* 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 */ + } + } - /* Empty? */ - if (line_endp == ihp) + if (ihp == &vdata[IMG_SHSIZE]) { + /* A long line, like "#! blah blah blah" without end */ return (ENOEXEC); + } + + /* Backtrack until we find the last non-whitespace */ + while (IS_EOL(*ihp) || IS_WHITESPACE(*ihp)) { + ihp--; + } + + /* The character after the last non-whitespace is our logical end of line */ + line_endp = ihp + 1; + + /* + * Now we have pointers to the usable part of: + * + * "#! /usr/bin/int first second third \n" + * ^ line_startp ^ line_endp + */ /* 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); + exec_reset_save_path(imgp); + exec_save_path(imgp, CAST_USER_ADDR_T(imgp->ip_interp_buffer), + UIO_SYSSPACE); - ihp = &vdata[2]; - while (ihp < line_endp) { - /* Skip leading whitespace before each argument */ - while ((*ihp == ' ') || (*ihp == '\t')) - ihp++; + /* 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'; - if (ihp >= line_endp) - break; + /* + * If we have a SUID oder 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)) { + p = vfs_context_proc(imgp->ip_vfs_context); + error = falloc(p, &fp, &fd, imgp->ip_vfs_context); + if (error) + return(error); - /* We have an argument; copy it */ - while ((ihp < line_endp) && (*ihp != ' ') && (*ihp != '\t')) { - *imgp->ip_strendp++ = *ihp++; - imgp->ip_strspace--; - } - *imgp->ip_strendp++ = 0; - imgp->ip_strspace--; - imgp->ip_argc++; + 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)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; } return (-3); @@ -407,9 +633,19 @@ 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. @@ -417,9 +653,10 @@ 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; @@ -431,6 +668,49 @@ exec_fat_imgact(struct image_params *imgp) 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) { + struct fat_arch *arches = (struct fat_arch *) (fat_header + 1); + int nfat_arch = 0, pr = 0, f = 0; + + nfat_arch = OSSwapBigToHostInt32(fat_header->nfat_arch); + /* 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 */ + break; + } + + for (f = 0; f < nfat_arch; f++) { + cpu_type_t archtype = OSSwapBigToHostInt32( + arches[f].cputype); + cpu_type_t archsubtype = OSSwapBigToHostInt32( + arches[f].cpusubtype) & ~CPU_SUBTYPE_MASK; + if (pref == archtype && + grade_binary(archtype, archsubtype)) { + /* We have a winner! */ + fat_arch.cputype = archtype; + fat_arch.cpusubtype = archsubtype; + fat_arch.offset = OSSwapBigToHostInt32( + arches[f].offset); + fat_arch.size = OSSwapBigToHostInt32( + arches[f].size); + fat_arch.align = OSSwapBigToHostInt32( + arches[f].align); + goto use_arch; + } + } + } + } + /* Look up our preferred architecture in the fat file. */ lret = fatfile_getarch_affinity(imgp->ip_vp, (vm_offset_t)fat_header, @@ -441,10 +721,11 @@ exec_fat_imgact(struct image_params *imgp) 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), + UIO_SYSSPACE, (IO_UNIT|IO_NODELOCKED), cred, &resid, p); if (error) { goto bad; @@ -462,6 +743,7 @@ exec_fat_imgact(struct image_params *imgp) imgp->ip_arch_size = (user_size_t)fat_arch.size; bad: + kauth_cred_unref(&cred); return (error); } @@ -470,27 +752,43 @@ 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); + proc_t p = vfs_context_proc(imgp->ip_vfs_context); int error = 0; int vfexec = 0; task_t task; - task_t new_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; - + struct _posix_spawnattr *psa = NULL; + int spawn = (imgp->ip_flags & IMGPF_SPAWN); + int apptype = 0; + /* * 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 @@ -498,65 +796,120 @@ exec_mach_imgact(struct image_params *imgp) */ if ((mach_header->magic != MH_MAGIC) && (mach_header->magic != MH_MAGIC_64)) { - error = -1; + error = -1; + goto bad; + } + + switch (mach_header->filetype) { + case MH_DYLIB: + case MH_BUNDLE: + error = -1; goto bad; } + if (!imgp->ip_origcputype) { + imgp->ip_origcputype = mach_header->cputype; + imgp->ip_origcpusubtype = mach_header->cpusubtype; + } + task = current_task(); thread = current_thread(); uthread = get_bsdthread_info(thread); + /* + * Save off the vfexec state up front; we have to do this, because + * we need to know if we were in this state initially subsequent to + * creating the backing task, thread, and uthread for the child + * process (from the vfs_context_t from in img_parms). + */ 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; - if (!grade_binary(mach_header->cputype, mach_header->cpusubtype)) { + /* 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 (pref == CPU_TYPE_ANY) { + /* Jump to regular grading */ + goto grade; + } + + if (pref == imgp->ip_origcputype) { + /* We have a match! */ + goto grade; + } + } error = EBADARCH; goto bad; } +grade: + if (!grade_binary(imgp->ip_origcputype & ~CPU_SUBTYPE_LIB64, + 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; + + error = exec_add_apple_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); +#ifdef IMGPF_POWERPC /* - * 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). + * XXX + * + * Should be factored out; this is here because we might be getting + * invoked this way as the result of a shell script, and the check + * in exec_check_permissions() is not interior to the jump back up + * to the "encapsulated_binary:" label in exec_activate_image(). */ - if (imgp->ip_user_argv != 0LL) { - error = exec_extract_strings(imgp); - if (error) - goto bad; + if (imgp->ip_vattr->va_fsid == exec_archhandler_ppc.fsid && + imgp->ip_vattr->va_fileid == exec_archhandler_ppc.fileid) { + imgp->ip_flags |= IMGPF_POWERPC; } +#endif /* IMGPF_POWERPC */ /* - * 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. - */ - 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)); - - - 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; + * 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 (vfexec || spawn) { + if (vfexec) { + imgp->ip_new_thread = fork_create_child(task, p, FALSE, (imgp->ip_flags & IMGPF_IS_64BIT)); + 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); + map = get_task_map(task); } else { map = VM_MAP_NULL; } @@ -565,84 +918,93 @@ exec_mach_imgact(struct image_params *imgp) * We set these flags here; this is OK, since if we fail after * this point, we have already destroyed the parent process anyway. */ + task_set_dyld_info(task, MACH_VM_MIN_ADDRESS, 0); if (imgp->ip_flags & IMGPF_IS_64BIT) { task_set_64bit(task, TRUE); - p->p_flag |= P_LP64; + OSBitOrAtomic(P_LP64, &p->p_flag); } else { task_set_64bit(task, FALSE); - p->p_flag &= ~P_LP64; + OSBitAndAtomic(~((uint32_t)P_LP64), &p->p_flag); } /* * 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); - } - - 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 + * destroyed or overwritten some process state while attempting an * execve() following a vfork(), which is an unrecoverable condition. */ - /* - * 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. - */ - task_set_64bit(task, - ((imgp->ip_flags & IMGPF_IS_64BIT) == IMGPF_IS_64BIT)); - /* * Actually load the image file we previously decided to load. */ - lret = load_machfile(imgp, mach_header, thread, map, clean_regions, &load_result); + lret = load_machfile(imgp, mach_header, thread, map, &load_result); if (lret != LOAD_SUCCESS) { error = load_return_to_errno(lret); goto badtoolate; } - /* load_machfile() maps the vnode */ - (void)ubc_map(imgp->ip_vp, PROT_EXEC); - - /* - * Close file descriptors - * which specify close-on-exec. + vm_map_set_user_wire_limit(get_task_map(task), p->p_rlimit[RLIMIT_MEMLOCK].rlim_cur); + + /* + * Set code-signing flags if this binary is signed, or if parent has + * requested them on exec. + */ + if (load_result.csflags & CS_VALID) { + imgp->ip_csflags |= load_result.csflags & + (CS_VALID| + CS_HARD|CS_KILL|CS_EXEC_SET_HARD|CS_EXEC_SET_KILL); + } else { + imgp->ip_csflags &= ~CS_VALID; + } + + 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; + + + /* + * Set up the system reserved areas in the new address space. + */ + vm_map_exec(get_task_map(task), + task, + (void *) p->p_fd->fd_rdir, +#ifdef IMGPF_POWERPC + imgp->ip_flags & IMGPF_POWERPC ? + CPU_TYPE_POWERPC : +#endif + cpu_type()); + + /* + * Close file descriptors which specify close-on-exec. */ - fdexec(p); + fdexec(p, psa != NULL ? psa->psa_flags : 0); /* * deal with set[ug]id. */ error = exec_handle_sugid(imgp); - KNOTE(&p->p_klist, NOTE_EXEC); - - 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)) { + load_result.user_stack, + load_result.customstack, + p) != KERN_SUCCESS) { error = load_return_to_errno(LOAD_NOSPACE); goto badtoolate; } - if (vfexec) { - uthread->uu_ar0 = (void *)get_user_regs(thread); + if (vfexec || spawn) { old_map = vm_map_switch(get_task_map(task)); } @@ -656,7 +1018,7 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) ap = p->user_stack; error = exec_copyout_strings(imgp, &ap); if (error) { - if (vfexec) + if (vfexec || spawn) vm_map_switch(old_map); goto badtoolate; } @@ -666,18 +1028,22 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) if (load_result.dynlinker) { uint64_t ap; + int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 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) { + if (vfexec || spawn) + vm_map_switch(old_map); + goto badtoolate; } + task_set_dyld_info(task, load_result.all_image_info_addr, + load_result.all_image_info_size); } - if (vfexec) { + if (vfexec || spawn) { vm_map_switch(old_map); } /* Set the entry point */ @@ -697,11 +1063,15 @@ 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) shmexec(p); +#endif +#if SYSV_SEM /* Clean up the semaphores */ semexit(p); +#endif /* * Remember file name for accounting. @@ -722,49 +1092,137 @@ if((imgp->ip_flags & IMGPF_IS_64BIT) == 0) p->p_comm[imgp->ip_ndp->ni_cnd.cn_namelen] = '\0'; } - { - /* This is for kdebug */ - long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4; + pal_dbg_set_task_name( p->task ); - /* 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)); +// dtrace code cleanup needed +#if CONFIG_DTRACE + /* + * Invalidate any predicate evaluation already cached for this thread by DTrace. + * That's because we've just stored to p_comm and DTrace refers to that when it + * evaluates the "execname" special variable. uid and gid may have changed as well. + */ + dtrace_set_thread_predcache(current_thread(), 0); + + /* + * Free any outstanding lazy dof entries. It is imperative we + * always call dtrace_lazy_dofs_destroy, rather than null check + * and call if !NULL. If we NULL test, during lazy dof faulting + * we can race with the faulting code and proceed from here to + * beyond the helpers cleanup. The lazy dof faulting will then + * install new helpers which no longer belong to this process! + */ + dtrace_lazy_dofs_destroy(p); + + + /* + * Clean up any DTrace helpers for the process. + */ + if (p->p_dtrace_helpers != NULL && dtrace_helpers_cleanup) { + (*dtrace_helpers_cleanup)(p); + } + + /* + * Cleanup the DTrace provider associated with this process. + */ + proc_lock(p); + if (p->p_dtrace_probes && dtrace_fasttrap_exec_ptr) { + (*dtrace_fasttrap_exec_ptr)(p); + } + proc_unlock(p); +#endif + if (kdebug_enable) { + long dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4; + + /* + * Collect the pathname for tracing + */ + kdbg_trace_string(p, &dbg_arg1, &dbg_arg2, &dbg_arg3, &dbg_arg4); - 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, + if (vfexec || spawn) { + KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_DATA, 2)) | DBG_FUNC_NONE, + p->p_pid ,0,0,0, (uintptr_t)thread_tid(thread)); + KERNEL_DEBUG_CONSTANT1((TRACEDBG_CODE(DBG_TRACE_STRING, 2)) | DBG_FUNC_NONE, + dbg_arg1, dbg_arg2, dbg_arg3, dbg_arg4, (uintptr_t)thread_tid(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); - } + } } - p->p_flag &= ~P_CLASSIC; +#ifdef IMGPF_POWERPC + /* + * Mark the process as powerpc or not. If powerpc, set the affinity + * flag, which will be used for grading binaries in future exec's + * from the process. + */ + if (((imgp->ip_flags & IMGPF_POWERPC) != 0)) + OSBitOrAtomic(P_TRANSLATED, &p->p_flag); + else +#endif /* IMGPF_POWERPC */ + OSBitAndAtomic(~((uint32_t)P_TRANSLATED), &p->p_flag); + OSBitAndAtomic(~((uint32_t)P_AFFINITY), &p->p_flag); + + /* + * 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(p->task); + } + if ((psa->psa_flags & POSIX_SPAWN_OSX_TALAPP_START) || (psa->psa_flags & POSIX_SPAWN_OSX_DBCLIENT_START) || (psa->psa_flags & POSIX_SPAWN_IOS_APP_START)) { + if ((psa->psa_flags & POSIX_SPAWN_OSX_TALAPP_START)) + apptype = PROC_POLICY_OSX_APPTYPE_TAL; + else if (psa->psa_flags & POSIX_SPAWN_OSX_DBCLIENT_START) + apptype = PROC_POLICY_OSX_APPTYPE_DBCLIENT; + else if (psa->psa_flags & POSIX_SPAWN_IOS_APP_START) + apptype = PROC_POLICY_IOS_APPTYPE; + else + apptype = 0; + proc_set_task_apptype(p->task, apptype); + if ((apptype == PROC_POLICY_OSX_APPTYPE_TAL) || + (apptype == PROC_POLICY_OSX_APPTYPE_DBCLIENT)) { + + proc_apply_task_networkbg_internal(p); + } + } + } /* * 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); } badtoolate: - if (vfexec) { +if (!spawn) + proc_knote(p, NOTE_EXEC); + + if (vfexec || spawn) { task_deallocate(new_task); thread_deallocate(thread); if (error) @@ -791,190 +1249,1159 @@ struct execsw { } execsw[] = { { exec_mach_imgact, "Mach-o Binary" }, { exec_fat_imgact, "Fat Binary" }, +#ifdef IMGPF_POWERPC + { exec_powerpc32_imgact, "PowerPC binary" }, +#endif /* IMGPF_POWERPC */ { 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 + * + * 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] */ -/* 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; - int i; - int resid, error; - task_t task; - int numthreads; - int vfexec=0; + int error; + int resid; 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() */ - - - imgp = &image_params; + int i; + int iterlimit = EAI_ITERLIMIT; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); - /* 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; + error = execargs_alloc(imgp); + if (error) + goto bad; + + error = exec_save_path(imgp, imgp->ip_user_fname, imgp->ip_seg); + if (error) { + goto bad_notrans; + } + + /* Use imgp->ip_strings, which contains the copyin-ed exec path */ + DTRACE_PROC1(exec, uintptr_t, imgp->ip_strings); + + NDINIT(&nd, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF | AUDITVNPATH1, + UIO_SYSSPACE, CAST_USER_ADDR_T(imgp->ip_strings), imgp->ip_vfs_context); + +again: + error = namei(&nd); + if (error) + goto bad_notrans; + imgp->ip_ndp = &nd; /* successful namei(); call nameidone() later */ + imgp->ip_vp = nd.ni_vp; /* if set, need to vnode_put() at some point */ + + /* + * 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. + */ + proc_lock(p); + if (p->p_lflag & P_LEXIT) { + proc_unlock(p); + goto bad_notrans; + } + error = proc_transstart(p, 1); + proc_unlock(p); + if (error) + goto bad_notrans; + + error = exec_check_permissions(imgp); + if (error) + goto bad; + + /* Copy; avoid invocation of an interpreter overwriting the original */ + if (once) { + once = 0; + *imgp->ip_origvattr = *imgp->ip_vattr; + } + + error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0, + UIO_SYSSPACE, IO_NODELOCKED, + vfs_context_ucred(imgp->ip_vfs_context), + &resid, vfs_context_proc(imgp->ip_vfs_context)); + if (error) + goto bad; + +encapsulated_binary: + /* Limit the number of iterations we will attempt on each binary */ + if (--iterlimit == 0) { + error = EBADEXEC; + goto bad; + } + error = -1; + 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 */ + goto encapsulated_binary; + + 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); +#endif + + nameidone(&nd); + + vnode_put(imgp->ip_vp); + imgp->ip_vp = NULL; /* already put */ + imgp->ip_ndp = NULL; /* already nameidone */ + + /* Use imgp->ip_strings, which exec_shell_imgact reset to the interpreter */ + NDINIT(&nd, LOOKUP, OP_LOOKUP, FOLLOW | LOCKLEAF, + UIO_SYSSPACE, CAST_USER_ADDR_T(imgp->ip_strings), imgp->ip_vfs_context); + +#ifdef IMGPF_POWERPC + /* + * PowerPC does not follow symlinks because the + * code which sets exec_archhandler_ppc.fsid and + * exec_archhandler_ppc.fileid doesn't follow them. + */ + if (imgp->ip_flags & IMGPF_POWERPC) + nd.ni_cnd.cn_flags &= ~FOLLOW; +#endif /* IMGPF_POWERPC */ + + 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(imgp->ip_vfs_context), + KAUTH_FILEOP_EXEC, + (uintptr_t)nd.ni_vp, 0); + } + +bad: + proc_transend(p, 0); + +bad_notrans: + if (imgp->ip_strings) + execargs_free(imgp); + if (imgp->ip_ndp) + nameidone(imgp->ip_ndp); + + return (error); +} + +/* + * exec_handle_port_actions + * + * 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 * Image parameter block + * short psa_flags posix spawn attribute flags + * + * Returns: 0 Success + * EINVAL Failure + * ENOTSUP Illegal posix_spawn attr flag was set + */ +static errno_t +exec_handle_port_actions(struct image_params *imgp, short psa_flags) +{ + _posix_spawn_port_actions_t pacts = imgp->ip_px_spa; + proc_t p = vfs_context_proc(imgp->ip_vfs_context); + _ps_port_action_t *act = NULL; + task_t task = p->task; + ipc_port_t port = NULL; + errno_t ret = KERN_SUCCESS; + int i; + + for (i = 0; i < pacts->pspa_count; i++) { + act = &pacts->pspa_actions[i]; + + if (ipc_object_copyin(get_task_ipcspace(current_task()), + CAST_MACH_PORT_TO_NAME(act->new_port), + MACH_MSG_TYPE_COPY_SEND, + (ipc_object_t *) &port) != KERN_SUCCESS) + return EINVAL; + + if (ret) + return ret; + + switch (act->port_type) { + case PSPA_SPECIAL: + /* Only allowed when not under vfork */ + if (!(psa_flags & POSIX_SPAWN_SETEXEC)) + return ENOTSUP; + ret = (task_set_special_port(task, + act->which, + port) == KERN_SUCCESS) ? 0 : EINVAL; + break; + case PSPA_EXCEPTION: + /* Only allowed when not under vfork */ + if (!(psa_flags & POSIX_SPAWN_SETEXEC)) + return ENOTSUP; + ret = (task_set_exception_ports(task, + act->mask, + port, + act->behavior, + act->flavor) == KERN_SUCCESS) ? 0 : EINVAL; + break; +#if CONFIG_AUDIT + case PSPA_AU_SESSION: + ret = audit_session_spawnjoin(p, + port); + break; +#endif + default: + ret = EINVAL; + } + /* action failed, so release port resources */ + if (ret) { + ipc_port_release_send(port); + return ret; + } + } + + 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. + */ + struct vnode_attr va; + struct nameidata nd; + int mode = psfa->psfaa_openargs.psfao_mode; + struct dup2_args dup2a; + struct close_nocancel_args ca; + int origfd; + + VATTR_INIT(&va); + /* Mask off all but regular access permissions */ + mode = ((mode &~ p->p_fd->fd_cmask) & ALLPERMS) & ~S_ISTXT; + VATTR_SET(&va, va_mode, mode & ACCESSPERMS); + + NDINIT(&nd, 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, + &nd, + psfa->psfaa_openargs.psfao_oflag, + &va, + ival); + + /* + * 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 fileproc *fp; + int fd = psfa->psfaa_filedes; + + /* + * Check to see if the descriptor exists, and + * ensure it's -not- marked as close-on-exec. + * [Less code than the equivalent F_GETFD/F_SETFD.] + */ + proc_fdlock(p); + if ((error = fp_lookup(p, fd, &fp, 1)) == 0) { + *fdflags(p, fd) &= ~UF_EXCLOSE; + (void) fp_drop(p, fd, fp, 1); + } + proc_fdunlock(p); + } + break; + + default: + error = EINVAL; + break; + } + + /* All file actions failures are considered fatal, per POSIX */ + + if (error) + 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); +} + + +/* + * 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; + char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for PowerPC */ + 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; + + /* + * 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 = &va; - imgp->ip_origvattr = &origva; + imgp->ip_vattr = vap; + imgp->ip_origvattr = origvap; 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 */ + imgp->ip_p_comm = alt_p_comm; /* for PowerPC */ + imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); - /* - * XXXAUDIT: Currently, we only audit the pathname of the binary. - * There may also be poor interaction with dyld. - */ + 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; - task = current_task(); + 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); + } + if (error) + goto bad; + + if (px_args.attr_size != 0) { + /* + * This could lose some of the port_actions pointer, + * but we already have it from px_args. + */ + if ((error = copyin(px_args.attrp, &px_sa, sizeof(px_sa))) != 0) + goto bad; + + 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); + if (px_args.file_actions_size < PSF_ACTIONS_SIZE(1) || + px_args.file_actions_size > PSF_ACTIONS_SIZE(maxfa)) { + 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; + } + 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; + } + } + + /* 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) { - 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); + 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)){ + if ((error = fork1(p, &imgp->ip_new_thread, PROC_CREATE_SPAWN)) != 0) + goto bad; + imgp->ip_flags |= IMGPF_SPAWN; /* spawn w/o exec */ + spawn_no_exec = TRUE; /* used in later tests */ + } + + if (spawn_no_exec) + p = (proc_t)get_bsdthreadtask_info(imgp->ip_new_thread); + assert(p != NULL); + + /* By default, the thread everyone plays with is the parent */ + context.vc_thread = current_thread(); + context.vc_ucred = p->p_ucred; /* XXX must NOT be kauth_cred_get() */ + + /* + * However, if we're not in the setexec case, redirect the context + * to the newly created process instead + */ + if (spawn_no_exec) + context.vc_thread = imgp->ip_new_thread; + + /* + * 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) { + /* + * The check for the POSIX_SPAWN_SETEXEC flag is done in + * exec_handle_port_actions(). + */ + if ((error = exec_handle_port_actions(imgp, + imgp->ip_px_sa != NULL ? px_sa.psa_flags : 0)) != 0) + goto bad; + } + + /* 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. + * + * The use of p_ucred is safe, since we are acting on the + * new process, and it has no threads other than the one + * we are creating for it. + */ + if (px_sa.psa_flags & POSIX_SPAWN_RESETIDS) { + kauth_cred_t my_cred = p->p_ucred; + kauth_cred_t my_new_cred = kauth_cred_setuidgid(my_cred, kauth_cred_getruid(my_cred), kauth_cred_getrgid(my_cred)); + if (my_new_cred != my_cred) { + p->p_ucred = my_new_cred; + /* update cred on proc */ + PROC_UPDATE_CREDS_ONPROC(p); } } + + /* + * Disable ASLR for the spawned process. + */ + if (px_sa.psa_flags & _POSIX_SPAWN_DISABLE_ASLR) + OSBitOrAtomic(P_DISABLE_ASLR, &p->p_flag); + + /* + * 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) { + /* 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 = current_thread(); + uthread_t child_uthread = uthread; + + /* + * If we created a new child thread, then the thread and + * uthread are different than the current ones; otherwise, + * we leave them, since we are in the exec case instead. + */ + if (spawn_no_exec) { + child_thread = imgp->ip_new_thread; + 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 = 0; sig < NSIG; sig++) + if (px_sa.psa_sigdefault & (1 << sig)) { + error = setsigvec(p, child_thread, sig + 1, &vec, spawn_no_exec); + } + } + } + +bad: + if (error == 0) { + /* 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); } - 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. + * 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. */ - error = exec_save_path(imgp, uap->fname, seg); + 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); + /* then flag exec has occurred */ + proc_knote(p, NOTE_EXEC); + DTRACE_PROC1(create, proc_t, p); + } + + /* + * 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 (imgp != NULL) { + if (imgp->ip_vp) + vnode_put(imgp->ip_vp); + 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_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 (error) { - execargs_free(imgp); - return(error); + DTRACE_PROC1(exec__failure, int, error); + } else { + /* + * temporary - so dtrace call to current_proc() + * returns the child process instead of the parent. + */ + if (imgp != NULL && imgp->ip_flags & IMGPF_SPAWN) { + p->p_lflag |= P_LINVFORK; + p->p_vforkact = current_thread(); + uthread->uu_proc = p; + uthread->uu_flag |= UT_VFORK; + } + + DTRACE_PROC(exec__success); + + /* + * temporary - so dtrace call to current_proc() + * returns the child process instead of the parent. + */ + if (imgp != NULL && imgp->ip_flags & IMGPF_SPAWN) { + p->p_lflag &= ~P_LINVFORK; + p->p_vforkact = NULL; + uthread->uu_proc = PROC_NULL; + uthread->uu_flag &= ~UT_VFORK; + } } - /* - * No app profiles under chroot - */ - 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++; - } - 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 */ + /* 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; - error = exec_check_permissions(imgp); - if (error) - goto bad; + /* + * 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); + if (exec_done == FALSE) { + task_deallocate(get_threadtask(imgp->ip_new_thread)); + thread_deallocate(imgp->ip_new_thread); + } + } else { + /* someone is doing it for us; just skip it */ + proc_unlock(p); + } + } else { - /* Copy; avoid invocation of an interpreter overwriting the original */ - if (once) { - once = 0; - origva = va; + /* + * Return" to the child + * + * Note: the image activator earlier dropped the + * task/thread references to the newly spawned + * process; this is OK, since we still have suspended + * queue references on them, so we should be fine + * with the delayed resume of the thread here. + */ + (void)thread_resume(imgp->ip_new_thread); + } + } + if (bufp != NULL) { + FREE(bufp, M_TEMP); } + + return(error); +} - error = vn_rdwr(UIO_READ, imgp->ip_vp, imgp->ip_vdata, PAGE_SIZE, 0, - UIO_SYSSPACE32, IO_NODELOCKED, cred, &resid, p); - if (error) - goto bad; - -encapsulated_binary: - error = -1; - for(i = 0; error == -1 && execsw[i].ex_imgact != NULL; i++) { - error = (*execsw[i].ex_imgact)(imgp); +/* + * 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; - switch (error) { - /* case -1: not claimed: continue */ - case -2: /* Encapsulated binary */ - goto encapsulated_binary; + muap.fname = uap->fname; + muap.argp = uap->argp; + muap.envp = uap->envp; + muap.mac_p = USER_ADDR_NULL; + err = __mac_execve(p, &muap, retval); - case -3: /* Interpreter */ - 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); + 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; + char alt_p_comm[sizeof(p->p_comm)] = {0}; /* for PowerPC */ + int is_64 = IS_64BIT_PROCESS(p); + struct vfs_context context; - nd.ni_segflg = UIO_SYSSPACE32; - nd.ni_dirp = CAST_USER_ADDR_T(imgp->ip_interp_name); - goto again; + context.vc_thread = current_thread(); + context.vc_ucred = kauth_cred_proc_ref(p); /* XXX must NOT be kauth_cred_get() */ - default: - break; - } + /* 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)); - /* 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); + /* 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 : IMGPF_NONE) | ((p->p_flag & P_DISABLE_ASLR) ? IMGPF_DISABLE_ASLR : IMGPF_NONE); + imgp->ip_p_comm = alt_p_comm; /* for PowerPC */ + imgp->ip_seg = (is_64 ? UIO_USERSPACE64 : UIO_USERSPACE32); + +#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 + + error = exec_activate_image(imgp); + + kauth_cred_unref(&context.vc_ucred); /* Image not claimed by any activator? */ if (error == -1) error = ENOEXEC; -bad: - if (imgp->ip_ndp) - nameidone(imgp->ip_ndp); - if (imgp->ip_vp) + if (error == 0) { + exec_resettextvp(p, imgp); + error = check_for_signature(p, imgp); + } + if (imgp->ip_vp != NULLVP) vnode_put(imgp->ip_vp); 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); +#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 (!error) { + struct uthread *uthread; + + /* Sever any extant thread affinity */ + thread_affinity_exec(current_thread()); + + DTRACE_PROC(exec__success); + uthread = get_bsdthread_info(current_thread()); + if (uthread->uu_flag & UT_VFORK) { + vfork_return(p, retval, p->p_pid); + (void)thread_resume(imgp->ip_new_thread); + } + } else { + DTRACE_PROC1(exec__failure, int, error); + } + +exit_with_error: + if (bufp != NULL) { + FREE(bufp, M_TEMP); } + 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) { @@ -993,6 +2420,20 @@ copyinptr(user_addr_t froma, user_addr_t *toptr, int ptr_size) } +/* + * 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) { @@ -1000,7 +2441,7 @@ copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size) if (ptr_size == 4) { /* 64 bit value containing 32 bit address */ - unsigned int i = CAST_DOWN(unsigned int,ua); /* SAFE */ + unsigned int i = CAST_DOWN_EXPLICIT(unsigned int,ua); /* SAFE */ error = copyout(&i, ptr, 4); } else { @@ -1028,167 +2469,230 @@ copyoutptr(user_addr_t ua, user_addr_t ptr, int ptr_size) * 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). + * end of the area consumed (stacks grow downward). * * 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 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 - * +-------------+ + * +-------------+ <- 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. - * - * TODO: argc copied with suword(), which takes a 64 bit address */ + static int exec_copyout_strings(struct image_params *imgp, user_addr_t *stackp) { - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); + proc_t 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 */ + int ptr_area_size; + void *ptr_buffer_start, *ptr_buffer; + int string_size; + 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 ptr_area; /* argv[], env[], applev[] */ + user_addr_t argc_area; /* argc */ user_addr_t stack; - int stringc = imgp->ip_argc + imgp->ip_envc; - int len; int error; - int strspace; + + 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; /* - * 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). + * All previous contributors to the string area + * should have aligned their sub-area */ - 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*/; + if (imgp->ip_strspace % ptr_size != 0) { + error = EINVAL; + goto bad; + } - /* Return the initial stack address: the location of argc */ - *stackp = ptr_area; + /* 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)(stack - path_area); + p->p_argslen = (int)(*stackp - string_area); + proc_unlock(p); + /* Return the initial stack address: the location of argc */ + *stackp = stack; /* - * 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); + * 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; - /* Save a NULL pointer below it */ - (void)copyoutptr(0LL, path_area - ptr_size, ptr_size); - - /* Save the pointer to "path" just below it */ - (void)copyoutptr(path_area, path_area - 2*ptr_size, ptr_size); +#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 */ - /* - * 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. - */ + /* + * 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 */ + } - /* 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 (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); + } } - /* - * 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. - */ - 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) - break; - - /* pointer: argv[n]/env[n] */ - (void)copyoutptr(string_area, ptr_area, ptr_size); + * Copy out all our pointer arrays in bulk. + */ + error = copyout(ptr_buffer_start, ptr_area, + ptr_area_size); + if (error) + goto bad; - /* 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; - } - /* env[n] = NULL */ - (void)copyoutptr(0LL, ptr_area, ptr_size); + /* 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); @@ -1201,6 +2705,11 @@ bad: * 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 * @@ -1210,42 +2719,112 @@ bad: * 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) * * - * Notes: The argument and environment vectors are user space pointers + * 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; - 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; + int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4; user_addr_t argv = imgp->ip_user_argv; user_addr_t envv = imgp->ip_user_envv; - /* Now, get rest of arguments */ + /* + * 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 */ + } /* - * 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. + * From now on, we start attributing string space to ip_argspace */ - if((imgp->ip_flags & IMGPF_INTERPRET) != 0 && argv != 0LL) { + 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++; + } - 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 (*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) { @@ -1255,23 +2834,37 @@ exec_extract_strings(struct image_params *imgp) if (error) goto bad; - argv += ptr_size; if (arg == 0LL) { break; - } else if (arg == (user_addr_t)-1) { - /* Um... why would it be -1? */ - error = EFAULT; - goto bad; } + + argv += ptr_size; + /* * av[n...] = arg[n] */ - error = exec_add_string(imgp, arg, seg); + 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; @@ -1283,31 +2876,183 @@ exec_extract_strings(struct image_params *imgp) 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); + 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; +} + +static char * +random_hex_str(char *str, int len) +{ + uint64_t low, high, value; + int idx; + char digit; + + /* A 64-bit value will only take 16 characters, plus '0x' and NULL. */ + if (len > 19) + len = 19; + + /* We need enough room for at least 1 digit */ + if (len < 4) + return (NULL); + + low = random(); + high = random(); + value = high << 32 | low; + + str[0] = '0'; + str[1] = 'x'; + for (idx = 2; idx < len - 1; idx++) { + digit = value & 0xf; + value = value >> 4; + if (digit < 10) + str[idx] = '0' + digit; + else + str[idx] = 'a' + (digit - 10); + } + str[idx] = '\0'; + return (str); +} + +/* + * 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=" + +/* + * Build up the contents of the apple[] string vector + */ +static int +exec_add_apple_strings(struct image_params *imgp) +{ + int i, error; + int new_ptr_size = (imgp->ip_flags & IMGPF_IS_64BIT) ? 8 : 4; + char guard[19]; + char guard_vec[strlen(GUARD_KEY) + 19 * GUARD_VALUES + 1]; + + char entropy[19]; + char entropy_vec[strlen(ENTROPY_KEY) + 19 * ENTROPY_VALUES + 1]; + + /* exec_save_path stored the first string */ + imgp->ip_applec = 1; + + /* + * Supply libc with a collection of random values to use when + * implementing -fstack-protector. + */ + (void)strlcpy(guard_vec, GUARD_KEY, sizeof (guard_vec)); + for (i = 0; i < GUARD_VALUES; i++) { + random_hex_str(guard, sizeof (guard)); + if (i) + (void)strlcat(guard_vec, ",", sizeof (guard_vec)); + (void)strlcat(guard_vec, guard, sizeof (guard_vec)); + } + + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(guard_vec), UIO_SYSSPACE, FALSE); + if (error) + goto bad; + imgp->ip_applec++; + + /* + * Supply libc with entropy for system malloc. + */ + (void)strlcpy(entropy_vec, ENTROPY_KEY, sizeof(entropy_vec)); + for (i = 0; i < ENTROPY_VALUES; i++) { + random_hex_str(entropy, sizeof (entropy)); + if (i) + (void)strlcat(entropy_vec, ",", sizeof (entropy_vec)); + (void)strlcat(entropy_vec, entropy, sizeof (entropy_vec)); + } + + error = exec_add_user_string(imgp, CAST_USER_ADDR_T(entropy_vec), UIO_SYSSPACE, FALSE); + if (error) + goto bad; + imgp->ip_applec++; + + /* Align the tail of the combined applev area */ + while (imgp->ip_strspace % new_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; - struct proc *p = vfs_context_proc(imgp->ip_vfs_context); + proc_t p = vfs_context_proc(imgp->ip_vfs_context); int error; kauth_action_t action; @@ -1331,7 +3076,7 @@ exec_check_permissions(struct image_params *imgp) * 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) + if (!vfs_authopaque(vnode_mount(vp)) && ((vap->va_mode & (S_IXUSR | S_IXGRP | S_IXOTH)) == 0)) return (EACCES); /* Disallow zero length files */ @@ -1342,34 +3087,60 @@ exec_check_permissions(struct image_params *imgp) 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_flag & P_TRACED)) + if ((vp->v_mount->mnt_flag & MNT_NOSUID) || (p->p_lflag & P_LTRACED)) vap->va_mode &= ~(VSUID | VSGID); +#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_flag & P_TRACED) + 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 */ - if (vp->v_writecount) + vnode_lock(vp); + if (vp->v_writecount) { + panic("going to return ETXTBSY %x", vp); + vnode_unlock(vp); return (ETXTBSY); + } + vnode_unlock(vp); +#endif + +#ifdef IMGPF_POWERPC + /* + * If the file we are about to attempt to load is the exec_handler_ppc, + * which is determined by matching the vattr fields against previously + * cached values, then we set the PowerPC environment flag. + */ + if (vap->va_fsid == exec_archhandler_ppc.fsid && + vap->va_fileid == exec_archhandler_ppc.fileid) { + imgp->ip_flags |= IMGPF_POWERPC; + } +#endif /* IMGPF_POWERPC */ /* 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 SUGI, then replace the credential with a + * 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, * @@ -1393,38 +3164,114 @@ static int exec_handle_sugid(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); + proc_t p = vfs_context_proc(imgp->ip_vfs_context); int i; + int leave_sugid_clear = 0; int error = 0; - static struct vnode *dev_null = NULLVP; +#if CONFIG_MACF + int mac_transition; + + /* + * 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_scriptlabelp, + imgp->ip_execlabelp, p); +#endif - p->p_flag &= ~P_SUGID; + 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 && - 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); - } + ((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 - /* - * Replace the credential with a copy of itself if euid or egid change. + + /* + * 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. */ if (imgp->ip_origvattr->va_mode & VSUID) { - p->p_ucred = kauth_cred_seteuid(p->p_ucred, imgp->ip_origvattr->va_uid); + p->p_ucred = kauth_cred_setresuid(p->p_ucred, KAUTH_UID_NONE, imgp->ip_origvattr->va_uid, imgp->ip_origvattr->va_uid, KAUTH_UID_NONE); + /* update cred on proc */ + PROC_UPDATE_CREDS_ONPROC(p); } if (imgp->ip_origvattr->va_mode & VSGID) { - p->p_ucred = kauth_cred_setegid(p->p_ucred, imgp->ip_origvattr->va_gid); + p->p_ucred = kauth_cred_setresgid(p->p_ucred, KAUTH_GID_NONE, imgp->ip_origvattr->va_gid, imgp->ip_origvattr->va_gid); + /* update cred on proc */ + PROC_UPDATE_CREDS_ONPROC(p); + } + +#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) { + kauth_cred_t my_cred; + if (kauth_proc_label_update_execve(p, + imgp->ip_vfs_context, + imgp->ip_vp, + imgp->ip_scriptlabelp, + imgp->ip_execlabelp)) { + /* + * 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; + } + + my_cred = kauth_cred_proc_ref(p); + mac_task_label_update_cred(my_cred, p->task); + kauth_cred_unref(&my_cred); } +#endif /* CONFIG_MACF */ /* * Have mach reset the task and thread ports. @@ -1432,248 +3279,316 @@ exec_handle_sugid(struct image_params *imgp) * 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; - - /* Cache the vnode for /dev/null the first time around */ - if (dev_null == NULLVP) { - struct nameidata nd1; - - NDINIT(&nd1, LOOKUP, FOLLOW, UIO_SYSSPACE32, - CAST_USER_ADDR_T("/dev/null"), - imgp->ip_vfs_context); + ipc_task_reset(p->task); + ipc_thread_reset((imgp->ip_new_thread != NULL) ? + imgp->ip_new_thread : current_thread()); - 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); - } - } + /* + * 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 on the basis of simply + * running this code. + */ + if (!leave_sugid_clear) + OSBitOrAtomic(P_SUGID, &p->p_flag); - /* Radar 2261856; setuid security hole fix */ - /* Patch from OpenBSD: A. Ramesh */ /* + * 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. */ - if (dev_null != NULLVP) { - for (i = 0; i < 3; i++) { - struct fileproc *fp; - int indx; + for (i = 0; i < 3; i++) { - if (p->p_fd->fd_ofiles[i] != NULL) - continue; + if (p->p_fd->fd_ofiles[i] != NULL) + continue; - if ((error = falloc(p, &fp, &indx)) != 0) - continue; + /* + * Do the kernel equivalent of + * + * (void) open("/dev/null", O_RDONLY); + */ - if ((error = vnode_ref_ext(dev_null, FREAD)) != 0) { - fp_free(p, indx, fp); - break; - } + struct fileproc *fp; + int indx; + + if ((error = falloc(p, + &fp, &indx, imgp->ip_vfs_context)) != 0) + continue; + + struct nameidata nd1; + + NDINIT(&nd1, LOOKUP, OP_OPEN, FOLLOW, UIO_SYSSPACE, + CAST_USER_ADDR_T("/dev/null"), + imgp->ip_vfs_context); - 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); + if ((error = vn_open(&nd1, FREAD, 0)) != 0) { + fp_free(p, indx, fp); + break; } - /* - * 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; + + struct fileglob *fg = fp->f_fglob; + + fg->fg_flag = FREAD; + fg->fg_type = DTYPE_VNODE; + fg->fg_ops = &vnops; + fg->fg_data = nd1.ni_vp; + + vnode_put(nd1.ni_vp); + + proc_fdlock(p); + procfdtbl_releasefd(p, indx, NULL); + fp_drop(p, indx, fp, 1); + proc_fdunlock(p); + } + } +#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 */ /* * 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); + p->p_ucred = kauth_cred_setsvuidgid(p->p_ucred, kauth_cred_getuid(p->p_ucred), kauth_cred_getgid(p->p_ucred)); + /* update cred on proc */ + PROC_UPDATE_CREDS_ONPROC(p); - /* XXX Obsolete; security token should not be separate from cred */ + /* Update the process' identity version and set the security token */ + p->p_idversion++; set_security_token(p); return(error); } + +/* + * create_unix_stack + * + * 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: p Process to set stack on + * user_stack Address to set stack for process to + * customstack FALSE if no custom stack in binary + * map Address map in which to allocate the + * new stack, if 'customstack' is FALSE + * + * Returns: KERN_SUCCESS Stack successfully created + * !KERN_SUCCESS Mach failure code + */ static kern_return_t create_unix_stack(vm_map_t map, user_addr_t user_stack, int customstack, - struct proc *p) + proc_t p) { - mach_vm_size_t size; - mach_vm_offset_t addr; + mach_vm_size_t size, prot_size; + mach_vm_offset_t addr, prot_addr; + kern_return_t kr; + proc_lock(p); p->user_stack = user_stack; + proc_unlock(p); + if (!customstack) { - size = mach_vm_round_page(unix_stack_size(p)); + /* + * 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. + */ + size = mach_vm_round_page(MAXSSIZ); +#if STACK_GROWTH_UP + addr = mach_vm_trunc_page(user_stack); +#else /* STACK_GROWTH_UP */ addr = mach_vm_trunc_page(user_stack - size); - return (mach_vm_allocate(map, &addr, size, +#endif /* STACK_GROWTH_UP */ + kr = mach_vm_allocate(map, &addr, size, VM_MAKE_TAG(VM_MEMORY_STACK) | - VM_FLAGS_FIXED)); - } else - return(KERN_SUCCESS); + VM_FLAGS_FIXED); + if (kr != KERN_SUCCESS) { + return kr; + } + /* + * And prevent access to what's above the current stack + * size limit for this process. + */ + prot_addr = addr; +#if STACK_GROWTH_UP + prot_addr += unix_stack_size(p); +#endif /* STACK_GROWTH_UP */ + prot_addr = mach_vm_round_page(prot_addr); + prot_size = mach_vm_trunc_page(size - unix_stack_size(p)); + 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 static char init_program_name[128] = "/sbin/launchd"; -static const char * other_init = "/sbin/mach_init"; - -char init_args[128] = ""; struct execve_args init_exec_args; -int init_attempts = 0; - +/* + * 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. + */ void -load_init_program(struct proc *p) +load_init_program(proc_t p) { vm_offset_t init_addr; - char *argv[3]; + int argc = 0; + uint32_t argv[3]; int error; - register_t retval[2]; - - error = 0; - - /* 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 ] */ - } + int retval[2]; - 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)); - } - - init_attempts++; - - if (error) { - printf("Load of %s failed, errno %d\n", - init_program_name, error); - error = 0; - boothowto |= RB_INITNAME; - continue; - } - - /* - * Copy out program name. - */ + /* + * Copy out program name. + */ - init_addr = VM_MIN_ADDRESS; - (void) vm_allocate(current_map(), &init_addr, - PAGE_SIZE, VM_FLAGS_ANYWHERE); - if (init_addr == 0) - init_addr++; + init_addr = VM_MIN_ADDRESS; + (void) vm_allocate(current_map(), &init_addr, PAGE_SIZE, + VM_FLAGS_ANYWHERE); + if (init_addr == 0) + init_addr++; - (void) copyout((caddr_t) init_program_name, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(init_program_name)+1); + (void) copyout((caddr_t) init_program_name, CAST_USER_ADDR_T(init_addr), + (unsigned) sizeof(init_program_name)+1); - argv[0] = (char *) init_addr; - init_addr += sizeof(init_program_name); - init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); + argv[argc++] = (uint32_t)init_addr; + init_addr += sizeof(init_program_name); + init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); - /* - * Put out first (and only) argument, similarly. - * Assumes everything fits in a page as allocated - * above. - */ + /* + * 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"; - (void) copyout((caddr_t) init_args, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(init_args)); + copyout(init_args, CAST_USER_ADDR_T(init_addr), + strlen(init_args)); - argv[1] = (char *) init_addr; - init_addr += sizeof(init_args); + argv[argc++] = (uint32_t)init_addr; + init_addr += strlen(init_args); init_addr = (vm_offset_t)ROUND_PTR(char, init_addr); - /* - * Null-end the argument list - */ + } - argv[2] = (char *) 0; - - /* - * Copy out the argument list. - */ - - (void) copyout((caddr_t) argv, - CAST_USER_ADDR_T(init_addr), - (unsigned) sizeof(argv)); + /* + * Null-end the argument list + */ + argv[argc] = 0; + + /* + * Copy out the argument list. + */ + + (void) copyout((caddr_t) argv, CAST_USER_ADDR_T(init_addr), + (unsigned) sizeof(argv)); - /* - * Set up argument block for fake call to execve. - */ + /* + * Set up argument block for fake call to execve. + */ - 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); + 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); - error = execve(p,&init_exec_args,retval); - } while (error); + error = execve(p,&init_exec_args,retval); + if (error) + panic("Process 1 exec of %s failed, errno %d", + init_program_name, error); } /* - * Convert a load_return_t to an errno. + * 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: - 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; + 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; } } @@ -1684,58 +3599,295 @@ load_return_to_errno(load_return_t lrtn) #include #include -extern semaphore_t execve_semaphore; - /* - * 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. + * 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. */ + + +static int execargs_waiters = 0; +lck_mtx_t *execargs_cache_lock; + +static void +execargs_lock_lock(void) { + lck_mtx_lock_spin(execargs_cache_lock); +} + +static void +execargs_lock_unlock(void) { + lck_mtx_unlock(execargs_cache_lock); +} + +static void +execargs_lock_sleep(void) { + lck_mtx_sleep(execargs_cache_lock, LCK_SLEEP_DEFAULT, &execargs_free_count, THREAD_UNINT); +} + +static kern_return_t +execargs_purgeable_allocate(char **execarg_address) { + kern_return_t kr = vm_allocate(bsd_pageable_map, (vm_offset_t *)execarg_address, BSD_PAGEABLE_SIZE_PER_EXEC, VM_FLAGS_ANYWHERE | VM_FLAGS_PURGABLE); + assert(kr == KERN_SUCCESS); + return kr; +} + +static kern_return_t +execargs_purgeable_reference(void *execarg_address) { + 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); + + assert(kr == KERN_SUCCESS); + return kr; +} + +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); + + assert(kr == KERN_SUCCESS); + + return kr; +} + +static void +execargs_wakeup_waiters(void) { + thread_wakeup(&execargs_free_count); +} + static int execargs_alloc(struct image_params *imgp) { kern_return_t kret; + int i, cache_index = -1; - 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); + execargs_lock_lock(); + + while (execargs_free_count == 0) { + execargs_waiters++; + execargs_lock_sleep(); + execargs_waiters--; + } + + execargs_free_count--; + + 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); + + execargs_lock_unlock(); + + if (cache_index == -1) { + kret = execargs_purgeable_allocate(&imgp->ip_strings); + } + else + kret = execargs_purgeable_reference(imgp->ip_strings); - kret = kmem_alloc_pageable(bsd_pageable_map, (vm_offset_t *)&imgp->ip_strings, NCARGS + PAGE_SIZE); - imgp->ip_vdata = imgp->ip_strings + NCARGS; + assert(kret == KERN_SUCCESS); if (kret != KERN_SUCCESS) { - semaphore_signal(execve_semaphore); 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 (0); } +/* + * execargs_free + * + * 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: 0 Success + * EINVAL Invalid argument + * EINTR Oeration interrupted + */ static int execargs_free(struct image_params *imgp) { kern_return_t kret; + int i; + boolean_t needs_wakeup = FALSE; + + kret = execargs_purgeable_volatilize(imgp->ip_strings); - 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); + execargs_lock_lock(); + execargs_free_count++; + + 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; + } + } + + assert(imgp->ip_strings == NULL); + + if (execargs_waiters > 0) + needs_wakeup = TRUE; + + execargs_lock_unlock(); + + if (needs_wakeup == TRUE) + execargs_wakeup_waiters(); + + return ((kret == KERN_SUCCESS ? 0 : EINVAL)); +} + +static void +exec_resettextvp(proc_t p, struct image_params *imgp) +{ + vnode_t vp; + off_t offset; + vnode_t tvp = p->p_textvp; + int ret; + + vp = imgp->ip_vp; + offset = imgp->ip_arch_offset; + + if (vp == NULLVP) + panic("exec_resettextvp: expected valid vp"); + + 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); + + if ( tvp != NULLVP) { + if (vnode_getwithref(tvp) == 0) { + vnode_rele(tvp); + vnode_put(tvp); + } + } + +} + +static int +check_for_signature(proc_t p, struct image_params *imgp) +{ + void *blob = NULL; + size_t length = 0; + mach_port_t port = NULL; + kern_return_t kr = KERN_FAILURE; + int error = EACCES; + unsigned char hash[SHA1_RESULTLEN]; + + /* + * 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); + + /* 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); + } + + /* If the process is not signed or if it contains + * entitlements, we need to communicate through the + * task_access_port to taskgated. taskgated will provide a + * detached code signature if present, and will enforce any + * restrictions on entitlements. taskgated returns + * KERN_SUCCESS if it has completed its work and the exec + * should continue, or KERN_FAILURE if the exec should fail. + */ + error = cs_entitlements_blob_get(p, &blob, &length); + + /* if signed and no entitlements, then we're done here */ + if ((p->p_csflags & CS_VALID) && NULL == blob) { + error = 0; + goto done; + } + + kr = task_get_task_access_port(p->task, &port); + if (KERN_SUCCESS != kr || !IPC_PORT_VALID(port)) { + error = 0; +#if !CONFIG_EMBEDDED + /* fatal on the desktop when entitlements are present */ + if (NULL != blob) + error = EACCES; +#endif + goto done; + } + + kr = find_code_signature(port, p->p_pid); + if (KERN_SUCCESS != kr) { + error = EACCES; + goto done; } + + /* Only do this if exec_resettextvp() did not fail */ + if (p->p_textvp != NULLVP) { + /* + * If there's a new code directory, mark this process + * as signed. + */ + if (0 == ubc_cs_getcdhash(p->p_textvp, p->p_textoff, hash)) { + proc_lock(p); + p->p_csflags |= CS_VALID; + proc_unlock(p); + } + } + +done: + if (0 != error) + /* make very sure execution fails */ + psignal(p, SIGKILL); + return error; } +