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;
45 * __ptrace_unlink - unlink ptracee and restore its execution state
46 * @child: ptracee to be unlinked
48 * Remove @child from the ptrace list, move it back to the original parent,
49 * and restore the execution state so that it conforms to the group stop
52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
55 * If the ptracer is exiting, the ptracee can be in any state.
57 * After detach, the ptracee should be in a state which conforms to the
58 * group stop. If the group is stopped or in the process of stopping, the
59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
60 * up from TASK_TRACED.
62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
64 * to but in the opposite direction of what happens while attaching to a
65 * stopped task. However, in this direction, the intermediate RUNNING
66 * state is not hidden even from the current ptracer and if it immediately
67 * re-attaches and performs a WNOHANG wait(2), it may fail.
70 * write_lock_irq(tasklist_lock)
72 void __ptrace_unlink(struct task_struct *child)
74 BUG_ON(!child->ptrace);
76 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
78 child->parent = child->real_parent;
79 list_del_init(&child->ptrace_entry);
81 spin_lock(&child->sighand->siglock);
84 * Clear all pending traps and TRAPPING. TRAPPING should be
85 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
87 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
88 task_clear_jobctl_trapping(child);
91 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
94 if (!(child->flags & PF_EXITING) &&
95 (child->signal->flags & SIGNAL_STOP_STOPPED ||
96 child->signal->group_stop_count)) {
97 child->jobctl |= JOBCTL_STOP_PENDING;
100 * This is only possible if this thread was cloned by the
101 * traced task running in the stopped group, set the signal
102 * for the future reports.
103 * FIXME: we should change ptrace_init_task() to handle this
106 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
107 child->jobctl |= SIGSTOP;
111 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
112 * @child in the butt. Note that @resume should be used iff @child
113 * is in TASK_TRACED; otherwise, we might unduly disrupt
114 * TASK_KILLABLE sleeps.
116 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
117 ptrace_signal_wake_up(child, true);
119 spin_unlock(&child->sighand->siglock);
122 /* Ensure that nothing can wake it up, even SIGKILL */
123 static bool ptrace_freeze_traced(struct task_struct *task)
127 /* Lockless, nobody but us can set this flag */
128 if (task->jobctl & JOBCTL_LISTENING)
131 spin_lock_irq(&task->sighand->siglock);
132 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
133 task->state = __TASK_TRACED;
136 spin_unlock_irq(&task->sighand->siglock);
141 static void ptrace_unfreeze_traced(struct task_struct *task)
143 if (task->state != __TASK_TRACED)
146 WARN_ON(!task->ptrace || task->parent != current);
148 spin_lock_irq(&task->sighand->siglock);
149 if (__fatal_signal_pending(task))
150 wake_up_state(task, __TASK_TRACED);
152 task->state = TASK_TRACED;
153 spin_unlock_irq(&task->sighand->siglock);
157 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
158 * @child: ptracee to check for
159 * @ignore_state: don't check whether @child is currently %TASK_TRACED
161 * Check whether @child is being ptraced by %current and ready for further
162 * ptrace operations. If @ignore_state is %false, @child also should be in
163 * %TASK_TRACED state and on return the child is guaranteed to be traced
164 * and not executing. If @ignore_state is %true, @child can be in any
168 * Grabs and releases tasklist_lock and @child->sighand->siglock.
171 * 0 on success, -ESRCH if %child is not ready.
173 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
178 * We take the read lock around doing both checks to close a
179 * possible race where someone else was tracing our child and
180 * detached between these two checks. After this locked check,
181 * we are sure that this is our traced child and that can only
182 * be changed by us so it's not changing right after this.
184 read_lock(&tasklist_lock);
185 if (child->ptrace && child->parent == current) {
186 WARN_ON(child->state == __TASK_TRACED);
188 * child->sighand can't be NULL, release_task()
189 * does ptrace_unlink() before __exit_signal().
191 if (ignore_state || ptrace_freeze_traced(child))
194 read_unlock(&tasklist_lock);
196 if (!ret && !ignore_state) {
197 if (!wait_task_inactive(child, __TASK_TRACED)) {
199 * This can only happen if may_ptrace_stop() fails and
200 * ptrace_stop() changes ->state back to TASK_RUNNING,
201 * so we should not worry about leaking __TASK_TRACED.
203 WARN_ON(child->state == __TASK_TRACED);
211 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
213 if (mode & PTRACE_MODE_NOAUDIT)
214 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
216 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
219 /* Returns 0 on success, -errno on denial. */
220 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
222 const struct cred *cred = current_cred(), *tcred;
227 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
228 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
232 /* May we inspect the given task?
233 * This check is used both for attaching with ptrace
234 * and for allowing access to sensitive information in /proc.
236 * ptrace_attach denies several cases that /proc allows
237 * because setting up the necessary parent/child relationship
238 * or halting the specified task is impossible.
241 /* Don't let security modules deny introspection */
242 if (same_thread_group(task, current))
245 if (mode & PTRACE_MODE_FSCREDS) {
246 caller_uid = cred->fsuid;
247 caller_gid = cred->fsgid;
250 * Using the euid would make more sense here, but something
251 * in userland might rely on the old behavior, and this
252 * shouldn't be a security problem since
253 * PTRACE_MODE_REALCREDS implies that the caller explicitly
254 * used a syscall that requests access to another process
255 * (and not a filesystem syscall to procfs).
257 caller_uid = cred->uid;
258 caller_gid = cred->gid;
260 tcred = __task_cred(task);
261 if (uid_eq(caller_uid, tcred->euid) &&
262 uid_eq(caller_uid, tcred->suid) &&
263 uid_eq(caller_uid, tcred->uid) &&
264 gid_eq(caller_gid, tcred->egid) &&
265 gid_eq(caller_gid, tcred->sgid) &&
266 gid_eq(caller_gid, tcred->gid))
268 if (ptrace_has_cap(tcred->user_ns, mode))
276 dumpable = get_dumpable(task->mm);
278 if (dumpable != SUID_DUMP_USER &&
279 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
285 return security_ptrace_access_check(task, mode);
288 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
292 err = __ptrace_may_access(task, mode);
297 static int ptrace_attach(struct task_struct *task, long request,
301 bool seize = (request == PTRACE_SEIZE);
308 if (flags & ~(unsigned long)PTRACE_O_MASK)
310 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
318 if (unlikely(task->flags & PF_KTHREAD))
320 if (same_thread_group(task, current))
324 * Protect exec's credential calculations against our interference;
325 * SUID, SGID and LSM creds get determined differently
328 retval = -ERESTARTNOINTR;
329 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
333 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
338 write_lock_irq(&tasklist_lock);
340 if (unlikely(task->exit_state))
341 goto unlock_tasklist;
343 goto unlock_tasklist;
348 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
349 flags |= PT_PTRACE_CAP;
351 task->ptrace = flags;
353 __ptrace_link(task, current);
355 /* SEIZE doesn't trap tracee on attach */
357 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
359 spin_lock(&task->sighand->siglock);
362 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
363 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
364 * will be cleared if the child completes the transition or any
365 * event which clears the group stop states happens. We'll wait
366 * for the transition to complete before returning from this
369 * This hides STOPPED -> RUNNING -> TRACED transition from the
370 * attaching thread but a different thread in the same group can
371 * still observe the transient RUNNING state. IOW, if another
372 * thread's WNOHANG wait(2) on the stopped tracee races against
373 * ATTACH, the wait(2) may fail due to the transient RUNNING.
375 * The following task_is_stopped() test is safe as both transitions
376 * in and out of STOPPED are protected by siglock.
378 if (task_is_stopped(task) &&
379 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
380 signal_wake_up_state(task, __TASK_STOPPED);
382 spin_unlock(&task->sighand->siglock);
386 write_unlock_irq(&tasklist_lock);
388 mutex_unlock(&task->signal->cred_guard_mutex);
392 * We do not bother to change retval or clear JOBCTL_TRAPPING
393 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
394 * not return to user-mode, it will exit and clear this bit in
395 * __ptrace_unlink() if it wasn't already cleared by the tracee;
396 * and until then nobody can ptrace this task.
398 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
399 proc_ptrace_connector(task, PTRACE_ATTACH);
406 * ptrace_traceme -- helper for PTRACE_TRACEME
408 * Performs checks and sets PT_PTRACED.
409 * Should be used by all ptrace implementations for PTRACE_TRACEME.
411 static int ptrace_traceme(void)
415 write_lock_irq(&tasklist_lock);
416 /* Are we already being traced? */
417 if (!current->ptrace) {
418 ret = security_ptrace_traceme(current->parent);
420 * Check PF_EXITING to ensure ->real_parent has not passed
421 * exit_ptrace(). Otherwise we don't report the error but
422 * pretend ->real_parent untraces us right after return.
424 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
425 current->ptrace = PT_PTRACED;
426 __ptrace_link(current, current->real_parent);
429 write_unlock_irq(&tasklist_lock);
435 * Called with irqs disabled, returns true if childs should reap themselves.
437 static int ignoring_children(struct sighand_struct *sigh)
440 spin_lock(&sigh->siglock);
441 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
442 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
443 spin_unlock(&sigh->siglock);
448 * Called with tasklist_lock held for writing.
449 * Unlink a traced task, and clean it up if it was a traced zombie.
450 * Return true if it needs to be reaped with release_task().
451 * (We can't call release_task() here because we already hold tasklist_lock.)
453 * If it's a zombie, our attachedness prevented normal parent notification
454 * or self-reaping. Do notification now if it would have happened earlier.
455 * If it should reap itself, return true.
457 * If it's our own child, there is no notification to do. But if our normal
458 * children self-reap, then this child was prevented by ptrace and we must
459 * reap it now, in that case we must also wake up sub-threads sleeping in
462 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
468 if (p->exit_state != EXIT_ZOMBIE)
471 dead = !thread_group_leader(p);
473 if (!dead && thread_group_empty(p)) {
474 if (!same_thread_group(p->real_parent, tracer))
475 dead = do_notify_parent(p, p->exit_signal);
476 else if (ignoring_children(tracer->sighand)) {
477 __wake_up_parent(p, tracer);
481 /* Mark it as in the process of being reaped. */
483 p->exit_state = EXIT_DEAD;
487 static int ptrace_detach(struct task_struct *child, unsigned int data)
489 if (!valid_signal(data))
492 /* Architecture-specific hardware disable .. */
493 ptrace_disable(child);
495 write_lock_irq(&tasklist_lock);
497 * We rely on ptrace_freeze_traced(). It can't be killed and
498 * untraced by another thread, it can't be a zombie.
500 WARN_ON(!child->ptrace || child->exit_state);
502 * tasklist_lock avoids the race with wait_task_stopped(), see
503 * the comment in ptrace_resume().
505 child->exit_code = data;
506 __ptrace_detach(current, child);
507 write_unlock_irq(&tasklist_lock);
509 proc_ptrace_connector(child, PTRACE_DETACH);
515 * Detach all tasks we were using ptrace on. Called with tasklist held
518 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
520 struct task_struct *p, *n;
522 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
523 if (unlikely(p->ptrace & PT_EXITKILL))
524 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
526 if (__ptrace_detach(tracer, p))
527 list_add(&p->ptrace_entry, dead);
531 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
537 int this_len, retval;
539 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
540 retval = access_process_vm(tsk, src, buf, this_len, 0);
546 if (copy_to_user(dst, buf, retval))
556 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
562 int this_len, retval;
564 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
565 if (copy_from_user(buf, src, this_len))
567 retval = access_process_vm(tsk, dst, buf, this_len, 1);
581 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
585 if (data & ~(unsigned long)PTRACE_O_MASK)
588 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
589 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
590 !IS_ENABLED(CONFIG_SECCOMP))
593 if (!capable(CAP_SYS_ADMIN))
596 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
597 current->ptrace & PT_SUSPEND_SECCOMP)
601 /* Avoid intermediate state when all opts are cleared */
602 flags = child->ptrace;
603 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
604 flags |= (data << PT_OPT_FLAG_SHIFT);
605 child->ptrace = flags;
610 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
615 if (lock_task_sighand(child, &flags)) {
617 if (likely(child->last_siginfo != NULL)) {
618 *info = *child->last_siginfo;
621 unlock_task_sighand(child, &flags);
626 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
631 if (lock_task_sighand(child, &flags)) {
633 if (likely(child->last_siginfo != NULL)) {
634 *child->last_siginfo = *info;
637 unlock_task_sighand(child, &flags);
642 static int ptrace_peek_siginfo(struct task_struct *child,
646 struct ptrace_peeksiginfo_args arg;
647 struct sigpending *pending;
651 ret = copy_from_user(&arg, (void __user *) addr,
652 sizeof(struct ptrace_peeksiginfo_args));
656 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
657 return -EINVAL; /* unknown flags */
662 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
663 pending = &child->signal->shared_pending;
665 pending = &child->pending;
667 for (i = 0; i < arg.nr; ) {
669 s32 off = arg.off + i;
671 spin_lock_irq(&child->sighand->siglock);
672 list_for_each_entry(q, &pending->list, list) {
674 copy_siginfo(&info, &q->info);
678 spin_unlock_irq(&child->sighand->siglock);
680 if (off >= 0) /* beyond the end of the list */
684 if (unlikely(in_compat_syscall())) {
685 compat_siginfo_t __user *uinfo = compat_ptr(data);
687 if (copy_siginfo_to_user32(uinfo, &info) ||
688 __put_user(info.si_code, &uinfo->si_code)) {
696 siginfo_t __user *uinfo = (siginfo_t __user *) data;
698 if (copy_siginfo_to_user(uinfo, &info) ||
699 __put_user(info.si_code, &uinfo->si_code)) {
705 data += sizeof(siginfo_t);
708 if (signal_pending(current))
720 #ifdef PTRACE_SINGLESTEP
721 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
723 #define is_singlestep(request) 0
726 #ifdef PTRACE_SINGLEBLOCK
727 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
729 #define is_singleblock(request) 0
733 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
735 #define is_sysemu_singlestep(request) 0
738 static int ptrace_resume(struct task_struct *child, long request,
743 if (!valid_signal(data))
746 if (request == PTRACE_SYSCALL)
747 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
749 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
751 #ifdef TIF_SYSCALL_EMU
752 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
753 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
755 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
758 if (is_singleblock(request)) {
759 if (unlikely(!arch_has_block_step()))
761 user_enable_block_step(child);
762 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
763 if (unlikely(!arch_has_single_step()))
765 user_enable_single_step(child);
767 user_disable_single_step(child);
771 * Change ->exit_code and ->state under siglock to avoid the race
772 * with wait_task_stopped() in between; a non-zero ->exit_code will
773 * wrongly look like another report from tracee.
775 * Note that we need siglock even if ->exit_code == data and/or this
776 * status was not reported yet, the new status must not be cleared by
777 * wait_task_stopped() after resume.
779 * If data == 0 we do not care if wait_task_stopped() reports the old
780 * status and clears the code too; this can't race with the tracee, it
781 * takes siglock after resume.
783 need_siglock = data && !thread_group_empty(current);
785 spin_lock_irq(&child->sighand->siglock);
786 child->exit_code = data;
787 wake_up_state(child, __TASK_TRACED);
789 spin_unlock_irq(&child->sighand->siglock);
794 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
796 static const struct user_regset *
797 find_regset(const struct user_regset_view *view, unsigned int type)
799 const struct user_regset *regset;
802 for (n = 0; n < view->n; ++n) {
803 regset = view->regsets + n;
804 if (regset->core_note_type == type)
811 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
814 const struct user_regset_view *view = task_user_regset_view(task);
815 const struct user_regset *regset = find_regset(view, type);
818 if (!regset || (kiov->iov_len % regset->size) != 0)
821 regset_no = regset - view->regsets;
822 kiov->iov_len = min(kiov->iov_len,
823 (__kernel_size_t) (regset->n * regset->size));
825 if (req == PTRACE_GETREGSET)
826 return copy_regset_to_user(task, view, regset_no, 0,
827 kiov->iov_len, kiov->iov_base);
829 return copy_regset_from_user(task, view, regset_no, 0,
830 kiov->iov_len, kiov->iov_base);
834 * This is declared in linux/regset.h and defined in machine-dependent
835 * code. We put the export here, near the primary machine-neutral use,
836 * to ensure no machine forgets it.
838 EXPORT_SYMBOL_GPL(task_user_regset_view);
841 int ptrace_request(struct task_struct *child, long request,
842 unsigned long addr, unsigned long data)
844 bool seized = child->ptrace & PT_SEIZED;
846 siginfo_t siginfo, *si;
847 void __user *datavp = (void __user *) data;
848 unsigned long __user *datalp = datavp;
852 case PTRACE_PEEKTEXT:
853 case PTRACE_PEEKDATA:
854 return generic_ptrace_peekdata(child, addr, data);
855 case PTRACE_POKETEXT:
856 case PTRACE_POKEDATA:
857 return generic_ptrace_pokedata(child, addr, data);
859 #ifdef PTRACE_OLDSETOPTIONS
860 case PTRACE_OLDSETOPTIONS:
862 case PTRACE_SETOPTIONS:
863 ret = ptrace_setoptions(child, data);
865 case PTRACE_GETEVENTMSG:
866 ret = put_user(child->ptrace_message, datalp);
869 case PTRACE_PEEKSIGINFO:
870 ret = ptrace_peek_siginfo(child, addr, data);
873 case PTRACE_GETSIGINFO:
874 ret = ptrace_getsiginfo(child, &siginfo);
876 ret = copy_siginfo_to_user(datavp, &siginfo);
879 case PTRACE_SETSIGINFO:
880 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
883 ret = ptrace_setsiginfo(child, &siginfo);
886 case PTRACE_GETSIGMASK:
887 if (addr != sizeof(sigset_t)) {
892 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
899 case PTRACE_SETSIGMASK: {
902 if (addr != sizeof(sigset_t)) {
907 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
912 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
915 * Every thread does recalc_sigpending() after resume, so
916 * retarget_shared_pending() and recalc_sigpending() are not
919 spin_lock_irq(&child->sighand->siglock);
920 child->blocked = new_set;
921 spin_unlock_irq(&child->sighand->siglock);
927 case PTRACE_INTERRUPT:
929 * Stop tracee without any side-effect on signal or job
930 * control. At least one trap is guaranteed to happen
931 * after this request. If @child is already trapped, the
932 * current trap is not disturbed and another trap will
933 * happen after the current trap is ended with PTRACE_CONT.
935 * The actual trap might not be PTRACE_EVENT_STOP trap but
936 * the pending condition is cleared regardless.
938 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
942 * INTERRUPT doesn't disturb existing trap sans one
943 * exception. If ptracer issued LISTEN for the current
944 * STOP, this INTERRUPT should clear LISTEN and re-trap
947 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
948 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
950 unlock_task_sighand(child, &flags);
956 * Listen for events. Tracee must be in STOP. It's not
957 * resumed per-se but is not considered to be in TRACED by
958 * wait(2) or ptrace(2). If an async event (e.g. group
959 * stop state change) happens, tracee will enter STOP trap
960 * again. Alternatively, ptracer can issue INTERRUPT to
961 * finish listening and re-trap tracee into STOP.
963 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
966 si = child->last_siginfo;
967 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
968 child->jobctl |= JOBCTL_LISTENING;
970 * If NOTIFY is set, it means event happened between
971 * start of this trap and now. Trigger re-trap.
973 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
974 ptrace_signal_wake_up(child, true);
977 unlock_task_sighand(child, &flags);
980 case PTRACE_DETACH: /* detach a process that was attached. */
981 ret = ptrace_detach(child, data);
984 #ifdef CONFIG_BINFMT_ELF_FDPIC
985 case PTRACE_GETFDPIC: {
986 struct mm_struct *mm = get_task_mm(child);
987 unsigned long tmp = 0;
994 case PTRACE_GETFDPIC_EXEC:
995 tmp = mm->context.exec_fdpic_loadmap;
997 case PTRACE_GETFDPIC_INTERP:
998 tmp = mm->context.interp_fdpic_loadmap;
1005 ret = put_user(tmp, datalp);
1010 #ifdef PTRACE_SINGLESTEP
1011 case PTRACE_SINGLESTEP:
1013 #ifdef PTRACE_SINGLEBLOCK
1014 case PTRACE_SINGLEBLOCK:
1016 #ifdef PTRACE_SYSEMU
1018 case PTRACE_SYSEMU_SINGLESTEP:
1020 case PTRACE_SYSCALL:
1022 return ptrace_resume(child, request, data);
1025 if (child->exit_state) /* already dead */
1027 return ptrace_resume(child, request, SIGKILL);
1029 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1030 case PTRACE_GETREGSET:
1031 case PTRACE_SETREGSET: {
1033 struct iovec __user *uiov = datavp;
1035 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1038 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1039 __get_user(kiov.iov_len, &uiov->iov_len))
1042 ret = ptrace_regset(child, request, addr, &kiov);
1044 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1049 case PTRACE_SECCOMP_GET_FILTER:
1050 ret = seccomp_get_filter(child, addr, datavp);
1060 static struct task_struct *ptrace_get_task_struct(pid_t pid)
1062 struct task_struct *child;
1065 child = find_task_by_vpid(pid);
1067 get_task_struct(child);
1071 return ERR_PTR(-ESRCH);
1075 #ifndef arch_ptrace_attach
1076 #define arch_ptrace_attach(child) do { } while (0)
1079 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1080 unsigned long, data)
1082 struct task_struct *child;
1085 if (request == PTRACE_TRACEME) {
1086 ret = ptrace_traceme();
1088 arch_ptrace_attach(current);
1092 child = ptrace_get_task_struct(pid);
1093 if (IS_ERR(child)) {
1094 ret = PTR_ERR(child);
1098 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1099 ret = ptrace_attach(child, request, addr, data);
1101 * Some architectures need to do book-keeping after
1105 arch_ptrace_attach(child);
1106 goto out_put_task_struct;
1109 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1110 request == PTRACE_INTERRUPT);
1112 goto out_put_task_struct;
1114 ret = arch_ptrace(child, request, addr, data);
1115 if (ret || request != PTRACE_DETACH)
1116 ptrace_unfreeze_traced(child);
1118 out_put_task_struct:
1119 put_task_struct(child);
1124 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1130 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1131 if (copied != sizeof(tmp))
1133 return put_user(tmp, (unsigned long __user *)data);
1136 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1141 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1142 return (copied == sizeof(data)) ? 0 : -EIO;
1145 #if defined CONFIG_COMPAT
1147 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1148 compat_ulong_t addr, compat_ulong_t data)
1150 compat_ulong_t __user *datap = compat_ptr(data);
1151 compat_ulong_t word;
1156 case PTRACE_PEEKTEXT:
1157 case PTRACE_PEEKDATA:
1158 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1159 if (ret != sizeof(word))
1162 ret = put_user(word, datap);
1165 case PTRACE_POKETEXT:
1166 case PTRACE_POKEDATA:
1167 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1168 ret = (ret != sizeof(data) ? -EIO : 0);
1171 case PTRACE_GETEVENTMSG:
1172 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1175 case PTRACE_GETSIGINFO:
1176 ret = ptrace_getsiginfo(child, &siginfo);
1178 ret = copy_siginfo_to_user32(
1179 (struct compat_siginfo __user *) datap,
1183 case PTRACE_SETSIGINFO:
1184 memset(&siginfo, 0, sizeof siginfo);
1185 if (copy_siginfo_from_user32(
1186 &siginfo, (struct compat_siginfo __user *) datap))
1189 ret = ptrace_setsiginfo(child, &siginfo);
1191 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1192 case PTRACE_GETREGSET:
1193 case PTRACE_SETREGSET:
1196 struct compat_iovec __user *uiov =
1197 (struct compat_iovec __user *) datap;
1201 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1204 if (__get_user(ptr, &uiov->iov_base) ||
1205 __get_user(len, &uiov->iov_len))
1208 kiov.iov_base = compat_ptr(ptr);
1211 ret = ptrace_regset(child, request, addr, &kiov);
1213 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1219 ret = ptrace_request(child, request, addr, data);
1225 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1226 compat_long_t, addr, compat_long_t, data)
1228 struct task_struct *child;
1231 if (request == PTRACE_TRACEME) {
1232 ret = ptrace_traceme();
1236 child = ptrace_get_task_struct(pid);
1237 if (IS_ERR(child)) {
1238 ret = PTR_ERR(child);
1242 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1243 ret = ptrace_attach(child, request, addr, data);
1245 * Some architectures need to do book-keeping after
1249 arch_ptrace_attach(child);
1250 goto out_put_task_struct;
1253 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1254 request == PTRACE_INTERRUPT);
1256 ret = compat_arch_ptrace(child, request, addr, data);
1257 if (ret || request != PTRACE_DETACH)
1258 ptrace_unfreeze_traced(child);
1261 out_put_task_struct:
1262 put_task_struct(child);
1266 #endif /* CONFIG_COMPAT */