2 * linux/kernel/ptrace.c
4 * (C) Copyright 1999 Linus Torvalds
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
10 #include <linux/capability.h>
11 #include <linux/export.h>
12 #include <linux/sched.h>
13 #include <linux/errno.h>
15 #include <linux/highmem.h>
16 #include <linux/pagemap.h>
17 #include <linux/ptrace.h>
18 #include <linux/security.h>
19 #include <linux/signal.h>
20 #include <linux/uio.h>
21 #include <linux/audit.h>
22 #include <linux/pid_namespace.h>
23 #include <linux/syscalls.h>
24 #include <linux/uaccess.h>
25 #include <linux/regset.h>
26 #include <linux/hw_breakpoint.h>
27 #include <linux/cn_proc.h>
28 #include <linux/compat.h>
32 * ptrace a task: make the debugger its new parent and
33 * move it to the ptrace list.
35 * Must be called with the tasklist lock write-held.
37 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
39 BUG_ON(!list_empty(&child->ptrace_entry));
40 list_add(&child->ptrace_entry, &new_parent->ptraced);
41 child->parent = new_parent;
43 child->ptracer_cred = get_cred(__task_cred(new_parent));
48 * __ptrace_unlink - unlink ptracee and restore its execution state
49 * @child: ptracee to be unlinked
51 * Remove @child from the ptrace list, move it back to the original parent,
52 * and restore the execution state so that it conforms to the group stop
55 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
56 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
57 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
58 * If the ptracer is exiting, the ptracee can be in any state.
60 * After detach, the ptracee should be in a state which conforms to the
61 * group stop. If the group is stopped or in the process of stopping, the
62 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
63 * up from TASK_TRACED.
65 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
66 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
67 * to but in the opposite direction of what happens while attaching to a
68 * stopped task. However, in this direction, the intermediate RUNNING
69 * state is not hidden even from the current ptracer and if it immediately
70 * re-attaches and performs a WNOHANG wait(2), it may fail.
73 * write_lock_irq(tasklist_lock)
75 void __ptrace_unlink(struct task_struct *child)
77 const struct cred *old_cred;
78 BUG_ON(!child->ptrace);
81 child->parent = child->real_parent;
82 list_del_init(&child->ptrace_entry);
83 old_cred = child->ptracer_cred;
84 child->ptracer_cred = NULL;
87 spin_lock(&child->sighand->siglock);
90 * Clear all pending traps and TRAPPING. TRAPPING should be
91 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
93 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
94 task_clear_jobctl_trapping(child);
97 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
100 if (!(child->flags & PF_EXITING) &&
101 (child->signal->flags & SIGNAL_STOP_STOPPED ||
102 child->signal->group_stop_count)) {
103 child->jobctl |= JOBCTL_STOP_PENDING;
106 * This is only possible if this thread was cloned by the
107 * traced task running in the stopped group, set the signal
108 * for the future reports.
109 * FIXME: we should change ptrace_init_task() to handle this
112 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
113 child->jobctl |= SIGSTOP;
117 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
118 * @child in the butt. Note that @resume should be used iff @child
119 * is in TASK_TRACED; otherwise, we might unduly disrupt
120 * TASK_KILLABLE sleeps.
122 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
123 ptrace_signal_wake_up(child, true);
125 spin_unlock(&child->sighand->siglock);
128 /* Ensure that nothing can wake it up, even SIGKILL */
129 static bool ptrace_freeze_traced(struct task_struct *task)
133 /* Lockless, nobody but us can set this flag */
134 if (task->jobctl & JOBCTL_LISTENING)
137 spin_lock_irq(&task->sighand->siglock);
138 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
141 raw_spin_lock_irqsave(&task->pi_lock, flags);
142 if (task->state & __TASK_TRACED)
143 task->state = __TASK_TRACED;
145 task->saved_state = __TASK_TRACED;
146 raw_spin_unlock_irqrestore(&task->pi_lock, flags);
149 spin_unlock_irq(&task->sighand->siglock);
154 static void ptrace_unfreeze_traced(struct task_struct *task)
156 if (task->state != __TASK_TRACED)
159 WARN_ON(!task->ptrace || task->parent != current);
161 spin_lock_irq(&task->sighand->siglock);
162 if (__fatal_signal_pending(task))
163 wake_up_state(task, __TASK_TRACED);
165 task->state = TASK_TRACED;
166 spin_unlock_irq(&task->sighand->siglock);
170 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
171 * @child: ptracee to check for
172 * @ignore_state: don't check whether @child is currently %TASK_TRACED
174 * Check whether @child is being ptraced by %current and ready for further
175 * ptrace operations. If @ignore_state is %false, @child also should be in
176 * %TASK_TRACED state and on return the child is guaranteed to be traced
177 * and not executing. If @ignore_state is %true, @child can be in any
181 * Grabs and releases tasklist_lock and @child->sighand->siglock.
184 * 0 on success, -ESRCH if %child is not ready.
186 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
191 * We take the read lock around doing both checks to close a
192 * possible race where someone else was tracing our child and
193 * detached between these two checks. After this locked check,
194 * we are sure that this is our traced child and that can only
195 * be changed by us so it's not changing right after this.
197 read_lock(&tasklist_lock);
198 if (child->ptrace && child->parent == current) {
199 WARN_ON(child->state == __TASK_TRACED);
201 * child->sighand can't be NULL, release_task()
202 * does ptrace_unlink() before __exit_signal().
204 if (ignore_state || ptrace_freeze_traced(child))
207 read_unlock(&tasklist_lock);
209 if (!ret && !ignore_state) {
210 if (!wait_task_inactive(child, __TASK_TRACED)) {
212 * This can only happen if may_ptrace_stop() fails and
213 * ptrace_stop() changes ->state back to TASK_RUNNING,
214 * so we should not worry about leaking __TASK_TRACED.
216 WARN_ON(child->state == __TASK_TRACED);
224 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
226 if (mode & PTRACE_MODE_NOAUDIT)
227 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
229 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
232 /* Returns 0 on success, -errno on denial. */
233 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
235 const struct cred *cred = current_cred(), *tcred;
236 struct mm_struct *mm;
240 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
241 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
245 /* May we inspect the given task?
246 * This check is used both for attaching with ptrace
247 * and for allowing access to sensitive information in /proc.
249 * ptrace_attach denies several cases that /proc allows
250 * because setting up the necessary parent/child relationship
251 * or halting the specified task is impossible.
254 /* Don't let security modules deny introspection */
255 if (same_thread_group(task, current))
258 if (mode & PTRACE_MODE_FSCREDS) {
259 caller_uid = cred->fsuid;
260 caller_gid = cred->fsgid;
263 * Using the euid would make more sense here, but something
264 * in userland might rely on the old behavior, and this
265 * shouldn't be a security problem since
266 * PTRACE_MODE_REALCREDS implies that the caller explicitly
267 * used a syscall that requests access to another process
268 * (and not a filesystem syscall to procfs).
270 caller_uid = cred->uid;
271 caller_gid = cred->gid;
273 tcred = __task_cred(task);
274 if (uid_eq(caller_uid, tcred->euid) &&
275 uid_eq(caller_uid, tcred->suid) &&
276 uid_eq(caller_uid, tcred->uid) &&
277 gid_eq(caller_gid, tcred->egid) &&
278 gid_eq(caller_gid, tcred->sgid) &&
279 gid_eq(caller_gid, tcred->gid))
281 if (ptrace_has_cap(tcred->user_ns, mode))
289 ((get_dumpable(mm) != SUID_DUMP_USER) &&
290 !ptrace_has_cap(mm->user_ns, mode)))
293 return security_ptrace_access_check(task, mode);
296 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
300 err = __ptrace_may_access(task, mode);
305 static int ptrace_attach(struct task_struct *task, long request,
309 bool seize = (request == PTRACE_SEIZE);
316 if (flags & ~(unsigned long)PTRACE_O_MASK)
318 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
326 if (unlikely(task->flags & PF_KTHREAD))
328 if (same_thread_group(task, current))
332 * Protect exec's credential calculations against our interference;
333 * SUID, SGID and LSM creds get determined differently
336 retval = -ERESTARTNOINTR;
337 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
341 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
346 write_lock_irq(&tasklist_lock);
348 if (unlikely(task->exit_state))
349 goto unlock_tasklist;
351 goto unlock_tasklist;
355 task->ptrace = flags;
357 __ptrace_link(task, current);
359 /* SEIZE doesn't trap tracee on attach */
361 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
363 spin_lock(&task->sighand->siglock);
366 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
367 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
368 * will be cleared if the child completes the transition or any
369 * event which clears the group stop states happens. We'll wait
370 * for the transition to complete before returning from this
373 * This hides STOPPED -> RUNNING -> TRACED transition from the
374 * attaching thread but a different thread in the same group can
375 * still observe the transient RUNNING state. IOW, if another
376 * thread's WNOHANG wait(2) on the stopped tracee races against
377 * ATTACH, the wait(2) may fail due to the transient RUNNING.
379 * The following task_is_stopped() test is safe as both transitions
380 * in and out of STOPPED are protected by siglock.
382 if (task_is_stopped(task) &&
383 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
384 signal_wake_up_state(task, __TASK_STOPPED);
386 spin_unlock(&task->sighand->siglock);
390 write_unlock_irq(&tasklist_lock);
392 mutex_unlock(&task->signal->cred_guard_mutex);
395 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
396 TASK_UNINTERRUPTIBLE);
397 proc_ptrace_connector(task, PTRACE_ATTACH);
404 * ptrace_traceme -- helper for PTRACE_TRACEME
406 * Performs checks and sets PT_PTRACED.
407 * Should be used by all ptrace implementations for PTRACE_TRACEME.
409 static int ptrace_traceme(void)
413 write_lock_irq(&tasklist_lock);
414 /* Are we already being traced? */
415 if (!current->ptrace) {
416 ret = security_ptrace_traceme(current->parent);
418 * Check PF_EXITING to ensure ->real_parent has not passed
419 * exit_ptrace(). Otherwise we don't report the error but
420 * pretend ->real_parent untraces us right after return.
422 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
423 current->ptrace = PT_PTRACED;
424 __ptrace_link(current, current->real_parent);
427 write_unlock_irq(&tasklist_lock);
433 * Called with irqs disabled, returns true if childs should reap themselves.
435 static int ignoring_children(struct sighand_struct *sigh)
438 spin_lock(&sigh->siglock);
439 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
440 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
441 spin_unlock(&sigh->siglock);
446 * Called with tasklist_lock held for writing.
447 * Unlink a traced task, and clean it up if it was a traced zombie.
448 * Return true if it needs to be reaped with release_task().
449 * (We can't call release_task() here because we already hold tasklist_lock.)
451 * If it's a zombie, our attachedness prevented normal parent notification
452 * or self-reaping. Do notification now if it would have happened earlier.
453 * If it should reap itself, return true.
455 * If it's our own child, there is no notification to do. But if our normal
456 * children self-reap, then this child was prevented by ptrace and we must
457 * reap it now, in that case we must also wake up sub-threads sleeping in
460 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
466 if (p->exit_state != EXIT_ZOMBIE)
469 dead = !thread_group_leader(p);
471 if (!dead && thread_group_empty(p)) {
472 if (!same_thread_group(p->real_parent, tracer))
473 dead = do_notify_parent(p, p->exit_signal);
474 else if (ignoring_children(tracer->sighand)) {
475 __wake_up_parent(p, tracer);
479 /* Mark it as in the process of being reaped. */
481 p->exit_state = EXIT_DEAD;
485 static int ptrace_detach(struct task_struct *child, unsigned int data)
487 if (!valid_signal(data))
490 /* Architecture-specific hardware disable .. */
491 ptrace_disable(child);
492 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
494 write_lock_irq(&tasklist_lock);
496 * We rely on ptrace_freeze_traced(). It can't be killed and
497 * untraced by another thread, it can't be a zombie.
499 WARN_ON(!child->ptrace || child->exit_state);
501 * tasklist_lock avoids the race with wait_task_stopped(), see
502 * the comment in ptrace_resume().
504 child->exit_code = data;
505 __ptrace_detach(current, child);
506 write_unlock_irq(&tasklist_lock);
508 proc_ptrace_connector(child, PTRACE_DETACH);
514 * Detach all tasks we were using ptrace on. Called with tasklist held
517 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
519 struct task_struct *p, *n;
521 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
522 if (unlikely(p->ptrace & PT_EXITKILL))
523 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
525 if (__ptrace_detach(tracer, p))
526 list_add(&p->ptrace_entry, dead);
530 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
536 int this_len, retval;
538 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
539 retval = access_process_vm(tsk, src, buf, this_len, 0);
545 if (copy_to_user(dst, buf, retval))
555 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
561 int this_len, retval;
563 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
564 if (copy_from_user(buf, src, this_len))
566 retval = access_process_vm(tsk, dst, buf, this_len, 1);
580 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
584 if (data & ~(unsigned long)PTRACE_O_MASK)
587 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
588 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
589 !config_enabled(CONFIG_SECCOMP))
592 if (!capable(CAP_SYS_ADMIN))
595 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
596 current->ptrace & PT_SUSPEND_SECCOMP)
600 /* Avoid intermediate state when all opts are cleared */
601 flags = child->ptrace;
602 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
603 flags |= (data << PT_OPT_FLAG_SHIFT);
604 child->ptrace = flags;
609 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
614 if (lock_task_sighand(child, &flags)) {
616 if (likely(child->last_siginfo != NULL)) {
617 *info = *child->last_siginfo;
620 unlock_task_sighand(child, &flags);
625 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
630 if (lock_task_sighand(child, &flags)) {
632 if (likely(child->last_siginfo != NULL)) {
633 *child->last_siginfo = *info;
636 unlock_task_sighand(child, &flags);
641 static int ptrace_peek_siginfo(struct task_struct *child,
645 struct ptrace_peeksiginfo_args arg;
646 struct sigpending *pending;
650 ret = copy_from_user(&arg, (void __user *) addr,
651 sizeof(struct ptrace_peeksiginfo_args));
655 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
656 return -EINVAL; /* unknown flags */
661 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
662 pending = &child->signal->shared_pending;
664 pending = &child->pending;
666 for (i = 0; i < arg.nr; ) {
668 s32 off = arg.off + i;
670 spin_lock_irq(&child->sighand->siglock);
671 list_for_each_entry(q, &pending->list, list) {
673 copy_siginfo(&info, &q->info);
677 spin_unlock_irq(&child->sighand->siglock);
679 if (off >= 0) /* beyond the end of the list */
683 if (unlikely(is_compat_task())) {
684 compat_siginfo_t __user *uinfo = compat_ptr(data);
686 if (copy_siginfo_to_user32(uinfo, &info) ||
687 __put_user(info.si_code, &uinfo->si_code)) {
695 siginfo_t __user *uinfo = (siginfo_t __user *) data;
697 if (copy_siginfo_to_user(uinfo, &info) ||
698 __put_user(info.si_code, &uinfo->si_code)) {
704 data += sizeof(siginfo_t);
707 if (signal_pending(current))
719 #ifdef PTRACE_SINGLESTEP
720 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
722 #define is_singlestep(request) 0
725 #ifdef PTRACE_SINGLEBLOCK
726 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
728 #define is_singleblock(request) 0
732 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
734 #define is_sysemu_singlestep(request) 0
737 static int ptrace_resume(struct task_struct *child, long request,
742 if (!valid_signal(data))
745 if (request == PTRACE_SYSCALL)
746 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
748 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
750 #ifdef TIF_SYSCALL_EMU
751 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
752 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
754 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
757 if (is_singleblock(request)) {
758 if (unlikely(!arch_has_block_step()))
760 user_enable_block_step(child);
761 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
762 if (unlikely(!arch_has_single_step()))
764 user_enable_single_step(child);
766 user_disable_single_step(child);
770 * Change ->exit_code and ->state under siglock to avoid the race
771 * with wait_task_stopped() in between; a non-zero ->exit_code will
772 * wrongly look like another report from tracee.
774 * Note that we need siglock even if ->exit_code == data and/or this
775 * status was not reported yet, the new status must not be cleared by
776 * wait_task_stopped() after resume.
778 * If data == 0 we do not care if wait_task_stopped() reports the old
779 * status and clears the code too; this can't race with the tracee, it
780 * takes siglock after resume.
782 need_siglock = data && !thread_group_empty(current);
784 spin_lock_irq(&child->sighand->siglock);
785 child->exit_code = data;
786 wake_up_state(child, __TASK_TRACED);
788 spin_unlock_irq(&child->sighand->siglock);
793 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
795 static const struct user_regset *
796 find_regset(const struct user_regset_view *view, unsigned int type)
798 const struct user_regset *regset;
801 for (n = 0; n < view->n; ++n) {
802 regset = view->regsets + n;
803 if (regset->core_note_type == type)
810 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
813 const struct user_regset_view *view = task_user_regset_view(task);
814 const struct user_regset *regset = find_regset(view, type);
817 if (!regset || (kiov->iov_len % regset->size) != 0)
820 regset_no = regset - view->regsets;
821 kiov->iov_len = min(kiov->iov_len,
822 (__kernel_size_t) (regset->n * regset->size));
824 if (req == PTRACE_GETREGSET)
825 return copy_regset_to_user(task, view, regset_no, 0,
826 kiov->iov_len, kiov->iov_base);
828 return copy_regset_from_user(task, view, regset_no, 0,
829 kiov->iov_len, kiov->iov_base);
833 * This is declared in linux/regset.h and defined in machine-dependent
834 * code. We put the export here, near the primary machine-neutral use,
835 * to ensure no machine forgets it.
837 EXPORT_SYMBOL_GPL(task_user_regset_view);
840 int ptrace_request(struct task_struct *child, long request,
841 unsigned long addr, unsigned long data)
843 bool seized = child->ptrace & PT_SEIZED;
845 siginfo_t siginfo, *si;
846 void __user *datavp = (void __user *) data;
847 unsigned long __user *datalp = datavp;
851 case PTRACE_PEEKTEXT:
852 case PTRACE_PEEKDATA:
853 return generic_ptrace_peekdata(child, addr, data);
854 case PTRACE_POKETEXT:
855 case PTRACE_POKEDATA:
856 return generic_ptrace_pokedata(child, addr, data);
858 #ifdef PTRACE_OLDSETOPTIONS
859 case PTRACE_OLDSETOPTIONS:
861 case PTRACE_SETOPTIONS:
862 ret = ptrace_setoptions(child, data);
864 case PTRACE_GETEVENTMSG:
865 ret = put_user(child->ptrace_message, datalp);
868 case PTRACE_PEEKSIGINFO:
869 ret = ptrace_peek_siginfo(child, addr, data);
872 case PTRACE_GETSIGINFO:
873 ret = ptrace_getsiginfo(child, &siginfo);
875 ret = copy_siginfo_to_user(datavp, &siginfo);
878 case PTRACE_SETSIGINFO:
879 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
882 ret = ptrace_setsiginfo(child, &siginfo);
885 case PTRACE_GETSIGMASK:
886 if (addr != sizeof(sigset_t)) {
891 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
898 case PTRACE_SETSIGMASK: {
901 if (addr != sizeof(sigset_t)) {
906 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
911 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
914 * Every thread does recalc_sigpending() after resume, so
915 * retarget_shared_pending() and recalc_sigpending() are not
918 spin_lock_irq(&child->sighand->siglock);
919 child->blocked = new_set;
920 spin_unlock_irq(&child->sighand->siglock);
926 case PTRACE_INTERRUPT:
928 * Stop tracee without any side-effect on signal or job
929 * control. At least one trap is guaranteed to happen
930 * after this request. If @child is already trapped, the
931 * current trap is not disturbed and another trap will
932 * happen after the current trap is ended with PTRACE_CONT.
934 * The actual trap might not be PTRACE_EVENT_STOP trap but
935 * the pending condition is cleared regardless.
937 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
941 * INTERRUPT doesn't disturb existing trap sans one
942 * exception. If ptracer issued LISTEN for the current
943 * STOP, this INTERRUPT should clear LISTEN and re-trap
946 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
947 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
949 unlock_task_sighand(child, &flags);
955 * Listen for events. Tracee must be in STOP. It's not
956 * resumed per-se but is not considered to be in TRACED by
957 * wait(2) or ptrace(2). If an async event (e.g. group
958 * stop state change) happens, tracee will enter STOP trap
959 * again. Alternatively, ptracer can issue INTERRUPT to
960 * finish listening and re-trap tracee into STOP.
962 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
965 si = child->last_siginfo;
966 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
967 child->jobctl |= JOBCTL_LISTENING;
969 * If NOTIFY is set, it means event happened between
970 * start of this trap and now. Trigger re-trap.
972 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
973 ptrace_signal_wake_up(child, true);
976 unlock_task_sighand(child, &flags);
979 case PTRACE_DETACH: /* detach a process that was attached. */
980 ret = ptrace_detach(child, data);
983 #ifdef CONFIG_BINFMT_ELF_FDPIC
984 case PTRACE_GETFDPIC: {
985 struct mm_struct *mm = get_task_mm(child);
986 unsigned long tmp = 0;
993 case PTRACE_GETFDPIC_EXEC:
994 tmp = mm->context.exec_fdpic_loadmap;
996 case PTRACE_GETFDPIC_INTERP:
997 tmp = mm->context.interp_fdpic_loadmap;
1004 ret = put_user(tmp, datalp);
1009 #ifdef PTRACE_SINGLESTEP
1010 case PTRACE_SINGLESTEP:
1012 #ifdef PTRACE_SINGLEBLOCK
1013 case PTRACE_SINGLEBLOCK:
1015 #ifdef PTRACE_SYSEMU
1017 case PTRACE_SYSEMU_SINGLESTEP:
1019 case PTRACE_SYSCALL:
1021 return ptrace_resume(child, request, data);
1024 if (child->exit_state) /* already dead */
1026 return ptrace_resume(child, request, SIGKILL);
1028 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1029 case PTRACE_GETREGSET:
1030 case PTRACE_SETREGSET: {
1032 struct iovec __user *uiov = datavp;
1034 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1037 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1038 __get_user(kiov.iov_len, &uiov->iov_len))
1041 ret = ptrace_regset(child, request, addr, &kiov);
1043 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1048 case PTRACE_SECCOMP_GET_FILTER:
1049 ret = seccomp_get_filter(child, addr, datavp);
1059 static struct task_struct *ptrace_get_task_struct(pid_t pid)
1061 struct task_struct *child;
1064 child = find_task_by_vpid(pid);
1066 get_task_struct(child);
1070 return ERR_PTR(-ESRCH);
1074 #ifndef arch_ptrace_attach
1075 #define arch_ptrace_attach(child) do { } while (0)
1078 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1079 unsigned long, data)
1081 struct task_struct *child;
1084 if (request == PTRACE_TRACEME) {
1085 ret = ptrace_traceme();
1087 arch_ptrace_attach(current);
1091 child = ptrace_get_task_struct(pid);
1092 if (IS_ERR(child)) {
1093 ret = PTR_ERR(child);
1097 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1098 ret = ptrace_attach(child, request, addr, data);
1100 * Some architectures need to do book-keeping after
1104 arch_ptrace_attach(child);
1105 goto out_put_task_struct;
1108 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1109 request == PTRACE_INTERRUPT);
1111 goto out_put_task_struct;
1113 ret = arch_ptrace(child, request, addr, data);
1114 if (ret || request != PTRACE_DETACH)
1115 ptrace_unfreeze_traced(child);
1117 out_put_task_struct:
1118 put_task_struct(child);
1123 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1129 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1130 if (copied != sizeof(tmp))
1132 return put_user(tmp, (unsigned long __user *)data);
1135 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1140 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1141 return (copied == sizeof(data)) ? 0 : -EIO;
1144 #if defined CONFIG_COMPAT
1146 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1147 compat_ulong_t addr, compat_ulong_t data)
1149 compat_ulong_t __user *datap = compat_ptr(data);
1150 compat_ulong_t word;
1155 case PTRACE_PEEKTEXT:
1156 case PTRACE_PEEKDATA:
1157 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1158 if (ret != sizeof(word))
1161 ret = put_user(word, datap);
1164 case PTRACE_POKETEXT:
1165 case PTRACE_POKEDATA:
1166 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1167 ret = (ret != sizeof(data) ? -EIO : 0);
1170 case PTRACE_GETEVENTMSG:
1171 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1174 case PTRACE_GETSIGINFO:
1175 ret = ptrace_getsiginfo(child, &siginfo);
1177 ret = copy_siginfo_to_user32(
1178 (struct compat_siginfo __user *) datap,
1182 case PTRACE_SETSIGINFO:
1183 memset(&siginfo, 0, sizeof siginfo);
1184 if (copy_siginfo_from_user32(
1185 &siginfo, (struct compat_siginfo __user *) datap))
1188 ret = ptrace_setsiginfo(child, &siginfo);
1190 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1191 case PTRACE_GETREGSET:
1192 case PTRACE_SETREGSET:
1195 struct compat_iovec __user *uiov =
1196 (struct compat_iovec __user *) datap;
1200 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1203 if (__get_user(ptr, &uiov->iov_base) ||
1204 __get_user(len, &uiov->iov_len))
1207 kiov.iov_base = compat_ptr(ptr);
1210 ret = ptrace_regset(child, request, addr, &kiov);
1212 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1218 ret = ptrace_request(child, request, addr, data);
1224 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1225 compat_long_t, addr, compat_long_t, data)
1227 struct task_struct *child;
1230 if (request == PTRACE_TRACEME) {
1231 ret = ptrace_traceme();
1235 child = ptrace_get_task_struct(pid);
1236 if (IS_ERR(child)) {
1237 ret = PTR_ERR(child);
1241 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1242 ret = ptrace_attach(child, request, addr, data);
1244 * Some architectures need to do book-keeping after
1248 arch_ptrace_attach(child);
1249 goto out_put_task_struct;
1252 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1253 request == PTRACE_INTERRUPT);
1255 ret = compat_arch_ptrace(child, request, addr, data);
1256 if (ret || request != PTRACE_DETACH)
1257 ptrace_unfreeze_traced(child);
1260 out_put_task_struct:
1261 put_task_struct(child);
1265 #endif /* CONFIG_COMPAT */