]> git.saurik.com Git - apple/xnu.git/blobdiff - bsd/kern/mach_process.c
xnu-6153.81.5.tar.gz
[apple/xnu.git] / bsd / kern / mach_process.c
index 7ec55c799ee854661105f3361552614e4c2866ca..915a8cb45f3e1f6d47f3488ba91ee1f3d561c297 100644 (file)
@@ -2,7 +2,7 @@
  * Copyright (c) 2000-2006 Apple Computer, Inc. All rights reserved.
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
- * 
+ *
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
- * 
+ *
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
- * 
+ *
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
@@ -22,7 +22,7 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
- * 
+ *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
 /* Copyright (c) 1995 NeXT Computer, Inc. All Rights Reserved */
 #include <sys/mount_internal.h>
 #include <sys/sysproto.h>
 #include <sys/kdebug.h>
+#include <sys/codesign.h>               /* cs_allow_invalid() */
 
 #include <security/audit/audit.h>
 
 #include <kern/task.h>
 #include <kern/thread.h>
 
-#include <mach/task.h>                 /* for task_resume() */
-#include <kern/sched_prim.h>           /* for thread_exception_return() */
-
-#include <vm/vm_protos.h>              /* cs_allow_invalid() */
+#include <mach/task.h>                  /* for task_resume() */
+#include <kern/sched_prim.h>            /* for thread_exception_return() */
 
 #include <pexpert/pexpert.h>
 
+#if CONFIG_MACF
+#include <security/mac_framework.h>
+#endif
+
 /* XXX ken/bsd_kern.c - prototype should be in common header */
 int get_task_userstop(task_t);
 
 /* Macros to clear/set/test flags. */
-#define        SET(t, f)       (t) |= (f)
-#define        CLR(t, f)       (t) &= ~(f)
-#define        ISSET(t, f)     ((t) & (f))
+#define SET(t, f)       (t) |= (f)
+#define CLR(t, f)       (t) &= ~(f)
+#define ISSET(t, f)     ((t) & (f))
 
-extern thread_t        port_name_to_thread(mach_port_name_t port_name);
 extern thread_t get_firstthread(task_t);
 
 
@@ -115,10 +117,10 @@ extern thread_t get_firstthread(task_t);
 int
 ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
 {
-       struct proc *t = current_proc();        /* target process */
-       task_t          task;
-       thread_t        th_act;
-       struct uthread  *ut;
+       struct proc *t = current_proc();        /* target process */
+       task_t          task;
+       thread_t        th_act;
+       struct uthread  *ut;
        int tr_sigexc = 0;
        int error = 0;
        int stopped = 0;
@@ -129,103 +131,141 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
        AUDIT_ARG(value32, uap->data);
 
        if (uap->req == PT_DENY_ATTACH) {
+#if (DEVELOPMENT || DEBUG) && CONFIG_EMBEDDED
+               if (PE_i_can_has_debugger(NULL)) {
+                       return 0;
+               }
+#endif
                proc_lock(p);
                if (ISSET(p->p_lflag, P_LTRACED)) {
                        proc_unlock(p);
                        KERNEL_DEBUG_CONSTANT(BSDDBG_CODE(DBG_BSD_PROC, BSD_PROC_FRCEXIT) | DBG_FUNC_NONE,
-                                             p->p_pid, W_EXITCODE(ENOTSUP, 0), 4, 0, 0);
+                           p->p_pid, W_EXITCODE(ENOTSUP, 0), 4, 0, 0);
                        exit1(p, W_EXITCODE(ENOTSUP, 0), retval);
-                       /* drop funnel before we return */
+
                        thread_exception_return();
                        /* NOTREACHED */
                }
                SET(p->p_lflag, P_LNOATTACH);
                proc_unlock(p);
 
-               return(0);
+               return 0;
        }
 
        if (uap->req == PT_FORCEQUOTA) {
-               if (is_suser()) {
+               if (kauth_cred_issuser(kauth_cred_get())) {
                        OSBitOrAtomic(P_FORCEQUOTA, &t->p_flag);
-                       return (0);
-               } else
-                       return (EPERM);
+                       return 0;
+               } else {
+                       return EPERM;
+               }
        }
 
        /*
         *      Intercept and deal with "please trace me" request.
-        */      
+        */
        if (uap->req == PT_TRACE_ME) {
+retry_trace_me: ;
+               proc_t pproc = proc_parent(p);
+               if (pproc == NULL) {
+                       return EINVAL;
+               }
+#if CONFIG_MACF
+               /*
+                * NB: Cannot call kauth_authorize_process(..., KAUTH_PROCESS_CANTRACE, ...)
+                *     since that assumes the process being checked is the current process
+                *     when, in this case, it is the current process's parent.
+                *     Most of the other checks in cantrace() don't apply either.
+                */
+               if ((error = mac_proc_check_debug(pproc, p)) == 0) {
+#endif
                proc_lock(p);
+               /* Make sure the process wasn't re-parented. */
+               if (p->p_ppid != pproc->p_pid) {
+                       proc_unlock(p);
+                       proc_rele(pproc);
+                       goto retry_trace_me;
+               }
                SET(p->p_lflag, P_LTRACED);
                /* Non-attached case, our tracer is our parent. */
                p->p_oppid = p->p_ppid;
-               /* Check whether child and parent are allowed to run modified
-                * code (they'll have to) */
-               struct proc *pproc=proc_find(p->p_oppid);
                proc_unlock(p);
+               /* Child and parent will have to be able to run modified code. */
                cs_allow_invalid(p);
-               if(pproc) {
-                       cs_allow_invalid(pproc);
-                       proc_rele(pproc);
-               }
-               return(0);
+               cs_allow_invalid(pproc);
+#if CONFIG_MACF
+       }
+#endif
+               proc_rele(pproc);
+               return error;
        }
        if (uap->req == PT_SIGEXC) {
                proc_lock(p);
                if (ISSET(p->p_lflag, P_LTRACED)) {
                        SET(p->p_lflag, P_LSIGEXC);
                        proc_unlock(p);
-                       return(0);
+                       return 0;
                } else {
                        proc_unlock(p);
-                       return(EINVAL);
+                       return EINVAL;
                }
        }
 
-       /* 
-        * We do not want ptrace to do anything with kernel or launchd 
+       /*
+        * We do not want ptrace to do anything with kernel or launchd
         */
        if (uap->pid < 2) {
-               return(EPERM);
+               return EPERM;
        }
 
        /*
         *      Locate victim, and make sure it is traceable.
         */
-       if ((t = proc_find(uap->pid)) == NULL)
-                       return (ESRCH);
+       if ((t = proc_find(uap->pid)) == NULL) {
+               return ESRCH;
+       }
 
        AUDIT_ARG(process, t);
 
        task = t->task;
        if (uap->req == PT_ATTACHEXC) {
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
                uap->req = PT_ATTACH;
                tr_sigexc = 1;
        }
        if (uap->req == PT_ATTACH) {
-               int             err;
-               
-               if ( kauth_authorize_process(proc_ucred(p), KAUTH_PROCESS_CANTRACE, 
-                                                                        t, (uintptr_t)&err, 0, 0) == 0 ) {
+#pragma clang diagnostic pop
+               int             err;
+
+#if CONFIG_EMBEDDED
+               if (tr_sigexc == 0) {
+                       error = ENOTSUP;
+                       goto out;
+               }
+#endif
+
+               if (kauth_authorize_process(proc_ucred(p), KAUTH_PROCESS_CANTRACE,
+                   t, (uintptr_t)&err, 0, 0) == 0) {
                        /* it's OK to attach */
                        proc_lock(t);
                        SET(t->p_lflag, P_LTRACED);
-                       if (tr_sigexc) 
+                       if (tr_sigexc) {
                                SET(t->p_lflag, P_LSIGEXC);
-       
+                       }
+
                        t->p_oppid = t->p_ppid;
                        /* Check whether child and parent are allowed to run modified
                         * code (they'll have to) */
                        proc_unlock(t);
                        cs_allow_invalid(t);
                        cs_allow_invalid(p);
-                       if (t->p_pptr != p)
+                       if (t->p_pptr != p) {
                                proc_reparentlocked(t, p, 1, 0);
-       
+                       }
+
                        proc_lock(t);
-                       if (get_task_userstop(task) > 0 ) {
+                       if (get_task_userstop(task) > 0) {
                                stopped = 1;
                        }
                        t->p_xstat = 0;
@@ -236,17 +276,17 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
                         * issignal() again to properly connect to the tracing
                         * process.
                         */
-                       if (stopped)
-                               task_resume(task);       
+                       if (stopped) {
+                               task_resume(task);
+                       }
                        error = 0;
                        goto out;
-               }
-               else {
+               } else {
                        /* not allowed to attach, proper error code returned by kauth_authorize_process */
                        if (ISSET(t->p_lflag, P_LNOATTACH)) {
                                psignal(p, SIGSEGV);
                        }
-                       
+
                        error = err;
                        goto out;
                }
@@ -287,18 +327,23 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
         */
        /* proc lock is held here */
        switch (uap->req) {
-
        case PT_DETACH:
                if (t->p_oppid != t->p_ppid) {
                        struct proc *pp;
 
                        proc_unlock(t);
                        pp = proc_find(t->p_oppid);
-                       proc_reparentlocked(t, pp ? pp : initproc, 1, 0);
-                       if (pp != PROC_NULL)
+                       if (pp != PROC_NULL) {
+                               proc_reparentlocked(t, pp, 1, 0);
                                proc_rele(pp);
+                       } else {
+                               /* original parent exited while traced */
+                               proc_list_lock();
+                               t->p_listflag |= P_LIST_DEADPARENT;
+                               proc_list_unlock();
+                               proc_reparentlocked(t, initproc, 1, 0);
+                       }
                        proc_lock(t);
-                       
                }
 
                t->p_oppid = 0;
@@ -306,18 +351,24 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
                CLR(t->p_lflag, P_LSIGEXC);
                proc_unlock(t);
                goto resume;
-               
+
        case PT_KILL:
                /*
                 *      Tell child process to kill itself after it
                 *      is resumed by adding NSIG to p_cursig. [see issig]
                 */
                proc_unlock(t);
+#if CONFIG_MACF
+               error = mac_proc_check_signal(p, t, SIGKILL);
+               if (0 != error) {
+                       goto resume;
+               }
+#endif
                psignal(t, SIGKILL);
                goto resume;
 
-       case PT_STEP:                   /* single step the child */
-       case PT_CONTINUE:               /* continue the child */
+       case PT_STEP:                   /* single step the child */
+       case PT_CONTINUE:               /* continue the child */
                proc_unlock(t);
                th_act = (thread_t)get_firstthread(task);
                if (th_act == THREAD_NULL) {
@@ -337,27 +388,47 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
                }
 
                if (uap->data != 0) {
+#if CONFIG_MACF
+                       error = mac_proc_check_signal(p, t, uap->data);
+                       if (0 != error) {
+                               goto out;
+                       }
+#endif
                        psignal(t, uap->data);
-                }
+               }
 
                if (uap->req == PT_STEP) {
-                       /*
+                       /*
                         * set trace bit
+                        * we use sending SIGSTOP as a comparable security check.
                         */
+#if CONFIG_MACF
+                       error = mac_proc_check_signal(p, t, SIGSTOP);
+                       if (0 != error) {
+                               goto out;
+                       }
+#endif
                        if (thread_setsinglestep(th_act, 1) != KERN_SUCCESS) {
                                error = ENOTSUP;
                                goto out;
                        }
                } else {
-                       /*
+                       /*
                         * clear trace bit if on
+                        * we use sending SIGCONT as a comparable security check.
                         */
+#if CONFIG_MACF
+                       error = mac_proc_check_signal(p, t, SIGCONT);
+                       if (0 != error) {
+                               goto out;
+                       }
+#endif
                        if (thread_setsinglestep(th_act, 0) != KERN_SUCCESS) {
                                error = ENOTSUP;
                                goto out;
                        }
-               }       
-       resume:
+               }
+resume:
                proc_lock(t);
                t->p_xstat = uap->data;
                t->p_stat = SRUN;
@@ -367,31 +438,36 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
                        if ((t->p_lflag & P_LSIGEXC) == 0) {
                                task_resume(task);
                        }
-               } else
+               } else {
                        proc_unlock(t);
-                       
+               }
+
                break;
-               
+
        case PT_THUPDATE:  {
                proc_unlock(t);
                if ((unsigned)uap->data >= NSIG) {
                        error = EINVAL;
                        goto out;
                }
-               th_act = port_name_to_thread(CAST_MACH_PORT_TO_NAME(uap->addr));
-               if (th_act == THREAD_NULL)
-                       return (ESRCH);
+               th_act = port_name_to_thread(CAST_MACH_PORT_TO_NAME(uap->addr),
+                   PORT_TO_THREAD_NONE);
+               if (th_act == THREAD_NULL) {
+                       error = ESRCH;
+                       goto out;
+               }
                ut = (uthread_t)get_bsdthread_info(th_act);
-               if (uap->data)
+               if (uap->data) {
                        ut->uu_siglist |= sigmask(uap->data);
+               }
                proc_lock(t);
                t->p_xstat = uap->data;
                t->p_stat = SRUN;
                proc_unlock(t);
                thread_deallocate(th_act);
                error = 0;
-               }
-               break;
+       }
+       break;
        default:
                proc_unlock(t);
                error = EINVAL;
@@ -401,7 +477,7 @@ ptrace(struct proc *p, struct ptrace_args *uap, int32_t *retval)
        error = 0;
 out:
        proc_rele(t);
-       return(error);
+       return error;
 }
 
 
@@ -412,14 +488,14 @@ out:
 int
 cantrace(proc_t cur_procp, kauth_cred_t creds, proc_t traced_procp, int *errp)
 {
-       int             my_err;
+       int             my_err;
        /*
         * You can't trace a process if:
         *      (1) it's the process that's doing the tracing,
         */
        if (traced_procp->p_pid == cur_procp->p_pid) {
                *errp = EINVAL;
-               return (0);
+               return 0;
        }
 
        /*
@@ -427,7 +503,7 @@ cantrace(proc_t cur_procp, kauth_cred_t creds, proc_t traced_procp, int *errp)
         */
        if (ISSET(traced_procp->p_lflag, P_LTRACED)) {
                *errp = EBUSY;
-               return (0);
+               return 0;
        }
 
        /*
@@ -435,20 +511,28 @@ cantrace(proc_t cur_procp, kauth_cred_t creds, proc_t traced_procp, int *errp)
         *          (unless you're root).
         */
        if ((kauth_cred_getruid(creds) != kauth_cred_getruid(proc_ucred(traced_procp)) ||
-               ISSET(traced_procp->p_flag, P_SUGID)) &&
-               (my_err = suser(creds, &cur_procp->p_acflag)) != 0) {
+           ISSET(traced_procp->p_flag, P_SUGID)) &&
+           (my_err = suser(creds, &cur_procp->p_acflag)) != 0) {
                *errp = my_err;
-               return (0);
+               return 0;
        }
 
        if ((cur_procp->p_lflag & P_LTRACED) && isinferior(cur_procp, traced_procp)) {
                *errp = EPERM;
-               return (0);
+               return 0;
        }
 
        if (ISSET(traced_procp->p_lflag, P_LNOATTACH)) {
                *errp = EBUSY;
-               return (0);
+               return 0;
        }
-       return(1);
+
+#if CONFIG_MACF
+       if ((my_err = mac_proc_check_debug(cur_procp, traced_procp)) != 0) {
+               *errp = my_err;
+               return 0;
+       }
+#endif
+
+       return 1;
 }