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/*
* 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
* compliance with the License. The rights granted to you under the License
* may not be used to create, or enable the creation or redistribution of,
* unlawful or unlicensed copies of an Apple operating system, or to
* circumvent, violate, or enable the circumvention or violation of, any
* terms of an Apple operating system software license agreement.
*
* Please obtain a copy of the License at
* http://www.opensource.apple.com/apsl/ and read it before using this file.
*
* The Original Code and all software distributed under the License are
* distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
* EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
* INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE, 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 */
/*-
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
* (c) UNIX System Laboratories, Inc.
* All or some portions of this file are derived from material licensed
* to the University of California by American Telephone and Telegraph
* Co. or Unix System Laboratories, Inc. and are reproduced herein with
* the permission of UNIX System Laboratories, Inc.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* from: @(#)sys_process.c 8.1 (Berkeley) 6/10/93
*/
#include <machine/reg.h>
#include <machine/psl.h>
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc_internal.h>
#include <sys/kauth.h>
#include <sys/errno.h>
#include <sys/ptrace.h>
#include <sys/uio.h>
#include <sys/user.h>
#include <sys/sysctl.h>
#include <sys/wait.h>
#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 <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))
extern thread_t port_name_to_thread(mach_port_name_t port_name);
extern thread_t get_firstthread(task_t);
/*
* sys-trace system call.
*/
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;
int tr_sigexc = 0;
int error = 0;
int stopped = 0;
AUDIT_ARG(cmd, uap->req);
AUDIT_ARG(pid, uap->pid);
AUDIT_ARG(addr, uap->addr);
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);
exit1(p, W_EXITCODE(ENOTSUP, 0), retval);
thread_exception_return();
/* NOTREACHED */
}
SET(p->p_lflag, P_LNOATTACH);
proc_unlock(p);
return(0);
}
if (uap->req == PT_FORCEQUOTA) {
if (kauth_cred_issuser(kauth_cred_get())) {
OSBitOrAtomic(P_FORCEQUOTA, &t->p_flag);
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;
proc_unlock(p);
/* Child and parent will have to be able to run modified code. */
cs_allow_invalid(p);
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);
} else {
proc_unlock(p);
return(EINVAL);
}
}
/*
* We do not want ptrace to do anything with kernel or launchd
*/
if (uap->pid < 2) {
return(EPERM);
}
/*
* Locate victim, and make sure it is traceable.
*/
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) {
#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)
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)
proc_reparentlocked(t, p, 1, 0);
proc_lock(t);
if (get_task_userstop(task) > 0 ) {
stopped = 1;
}
t->p_xstat = 0;
proc_unlock(t);
psignal(t, SIGSTOP);
/*
* If the process was stopped, wake up and run through
* issignal() again to properly connect to the tracing
* process.
*/
if (stopped)
task_resume(task);
error = 0;
goto out;
}
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;
}
}
/*
* You can't do what you want to the process if:
* (1) It's not being traced at all,
*/
proc_lock(t);
if (!ISSET(t->p_lflag, P_LTRACED)) {
proc_unlock(t);
error = EPERM;
goto out;
}
/*
* (2) it's not being traced by _you_, or
*/
if (t->p_pptr != p) {
proc_unlock(t);
error = EBUSY;
goto out;
}
/*
* (3) it's not currently stopped.
*/
if (t->p_stat != SSTOP) {
proc_unlock(t);
error = EBUSY;
goto out;
}
/*
* Mach version of ptrace executes request directly here,
* thus simplifying the interaction of ptrace and signals.
*/
/* 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);
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;
CLR(t->p_lflag, P_LTRACED);
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 */
proc_unlock(t);
th_act = (thread_t)get_firstthread(task);
if (th_act == THREAD_NULL) {
error = EINVAL;
goto out;
}
/* force use of Mach SPIs (and task_for_pid security checks) to adjust PC */
if (uap->addr != (user_addr_t)1) {
error = ENOTSUP;
goto out;
}
if ((unsigned)uap->data >= NSIG) {
error = EINVAL;
goto out;
}
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:
proc_lock(t);
t->p_xstat = uap->data;
t->p_stat = SRUN;
if (t->sigwait) {
wakeup((caddr_t)&(t->sigwait));
proc_unlock(t);
if ((t->p_lflag & P_LSIGEXC) == 0) {
task_resume(task);
}
} 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) {
error = ESRCH;
goto out;
}
ut = (uthread_t)get_bsdthread_info(th_act);
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;
default:
proc_unlock(t);
error = EINVAL;
goto out;
}
error = 0;
out:
proc_rele(t);
return(error);
}
/*
* determine if one process (cur_procp) can trace another process (traced_procp).
*/
int
cantrace(proc_t cur_procp, kauth_cred_t creds, proc_t traced_procp, int *errp)
{
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);
}
/*
* (2) it's already being traced, or
*/
if (ISSET(traced_procp->p_lflag, P_LTRACED)) {
*errp = EBUSY;
return (0);
}
/*
* (3) it's not owned by you, or is set-id on exec
* (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) {
*errp = my_err;
return (0);
}
if ((cur_procp->p_lflag & P_LTRACED) && isinferior(cur_procp, traced_procp)) {
*errp = EPERM;
return (0);
}
if (ISSET(traced_procp->p_lflag, P_LNOATTACH)) {
*errp = EBUSY;
return (0);
}
#if CONFIG_MACF
if ((my_err = mac_proc_check_debug(cur_procp, traced_procp)) != 0) {
*errp = my_err;
return (0);
}
#endif
return(1);
}
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