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)) {
135 raw_spin_lock_irqsave(&task->pi_lock, flags);
136 if (task->state & __TASK_TRACED)
137 task->state = __TASK_TRACED;
139 task->saved_state = __TASK_TRACED;
140 raw_spin_unlock_irqrestore(&task->pi_lock, flags);
143 spin_unlock_irq(&task->sighand->siglock);
148 static void ptrace_unfreeze_traced(struct task_struct *task)
150 if (task->state != __TASK_TRACED)
153 WARN_ON(!task->ptrace || task->parent != current);
155 spin_lock_irq(&task->sighand->siglock);
156 if (__fatal_signal_pending(task))
157 wake_up_state(task, __TASK_TRACED);
159 task->state = TASK_TRACED;
160 spin_unlock_irq(&task->sighand->siglock);
164 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
165 * @child: ptracee to check for
166 * @ignore_state: don't check whether @child is currently %TASK_TRACED
168 * Check whether @child is being ptraced by %current and ready for further
169 * ptrace operations. If @ignore_state is %false, @child also should be in
170 * %TASK_TRACED state and on return the child is guaranteed to be traced
171 * and not executing. If @ignore_state is %true, @child can be in any
175 * Grabs and releases tasklist_lock and @child->sighand->siglock.
178 * 0 on success, -ESRCH if %child is not ready.
180 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
185 * We take the read lock around doing both checks to close a
186 * possible race where someone else was tracing our child and
187 * detached between these two checks. After this locked check,
188 * we are sure that this is our traced child and that can only
189 * be changed by us so it's not changing right after this.
191 read_lock(&tasklist_lock);
192 if (child->ptrace && child->parent == current) {
193 WARN_ON(child->state == __TASK_TRACED);
195 * child->sighand can't be NULL, release_task()
196 * does ptrace_unlink() before __exit_signal().
198 if (ignore_state || ptrace_freeze_traced(child))
201 read_unlock(&tasklist_lock);
203 if (!ret && !ignore_state) {
204 if (!wait_task_inactive(child, __TASK_TRACED)) {
206 * This can only happen if may_ptrace_stop() fails and
207 * ptrace_stop() changes ->state back to TASK_RUNNING,
208 * so we should not worry about leaking __TASK_TRACED.
210 WARN_ON(child->state == __TASK_TRACED);
218 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
220 if (mode & PTRACE_MODE_NOAUDIT)
221 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
223 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
226 /* Returns 0 on success, -errno on denial. */
227 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
229 const struct cred *cred = current_cred(), *tcred;
234 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
235 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
239 /* May we inspect the given task?
240 * This check is used both for attaching with ptrace
241 * and for allowing access to sensitive information in /proc.
243 * ptrace_attach denies several cases that /proc allows
244 * because setting up the necessary parent/child relationship
245 * or halting the specified task is impossible.
248 /* Don't let security modules deny introspection */
249 if (same_thread_group(task, current))
252 if (mode & PTRACE_MODE_FSCREDS) {
253 caller_uid = cred->fsuid;
254 caller_gid = cred->fsgid;
257 * Using the euid would make more sense here, but something
258 * in userland might rely on the old behavior, and this
259 * shouldn't be a security problem since
260 * PTRACE_MODE_REALCREDS implies that the caller explicitly
261 * used a syscall that requests access to another process
262 * (and not a filesystem syscall to procfs).
264 caller_uid = cred->uid;
265 caller_gid = cred->gid;
267 tcred = __task_cred(task);
268 if (uid_eq(caller_uid, tcred->euid) &&
269 uid_eq(caller_uid, tcred->suid) &&
270 uid_eq(caller_uid, tcred->uid) &&
271 gid_eq(caller_gid, tcred->egid) &&
272 gid_eq(caller_gid, tcred->sgid) &&
273 gid_eq(caller_gid, tcred->gid))
275 if (ptrace_has_cap(tcred->user_ns, mode))
283 dumpable = get_dumpable(task->mm);
285 if (dumpable != SUID_DUMP_USER &&
286 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
292 return security_ptrace_access_check(task, mode);
295 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
299 err = __ptrace_may_access(task, mode);
304 static int ptrace_attach(struct task_struct *task, long request,
308 bool seize = (request == PTRACE_SEIZE);
315 if (flags & ~(unsigned long)PTRACE_O_MASK)
317 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
325 if (unlikely(task->flags & PF_KTHREAD))
327 if (same_thread_group(task, current))
331 * Protect exec's credential calculations against our interference;
332 * SUID, SGID and LSM creds get determined differently
335 retval = -ERESTARTNOINTR;
336 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
340 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
345 write_lock_irq(&tasklist_lock);
347 if (unlikely(task->exit_state))
348 goto unlock_tasklist;
350 goto unlock_tasklist;
355 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
356 flags |= PT_PTRACE_CAP;
358 task->ptrace = flags;
360 __ptrace_link(task, current);
362 /* SEIZE doesn't trap tracee on attach */
364 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
366 spin_lock(&task->sighand->siglock);
369 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
370 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
371 * will be cleared if the child completes the transition or any
372 * event which clears the group stop states happens. We'll wait
373 * for the transition to complete before returning from this
376 * This hides STOPPED -> RUNNING -> TRACED transition from the
377 * attaching thread but a different thread in the same group can
378 * still observe the transient RUNNING state. IOW, if another
379 * thread's WNOHANG wait(2) on the stopped tracee races against
380 * ATTACH, the wait(2) may fail due to the transient RUNNING.
382 * The following task_is_stopped() test is safe as both transitions
383 * in and out of STOPPED are protected by siglock.
385 if (task_is_stopped(task) &&
386 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
387 signal_wake_up_state(task, __TASK_STOPPED);
389 spin_unlock(&task->sighand->siglock);
393 write_unlock_irq(&tasklist_lock);
395 mutex_unlock(&task->signal->cred_guard_mutex);
399 * We do not bother to change retval or clear JOBCTL_TRAPPING
400 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
401 * not return to user-mode, it will exit and clear this bit in
402 * __ptrace_unlink() if it wasn't already cleared by the tracee;
403 * and until then nobody can ptrace this task.
405 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
406 proc_ptrace_connector(task, PTRACE_ATTACH);
413 * ptrace_traceme -- helper for PTRACE_TRACEME
415 * Performs checks and sets PT_PTRACED.
416 * Should be used by all ptrace implementations for PTRACE_TRACEME.
418 static int ptrace_traceme(void)
422 write_lock_irq(&tasklist_lock);
423 /* Are we already being traced? */
424 if (!current->ptrace) {
425 ret = security_ptrace_traceme(current->parent);
427 * Check PF_EXITING to ensure ->real_parent has not passed
428 * exit_ptrace(). Otherwise we don't report the error but
429 * pretend ->real_parent untraces us right after return.
431 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
432 current->ptrace = PT_PTRACED;
433 __ptrace_link(current, current->real_parent);
436 write_unlock_irq(&tasklist_lock);
442 * Called with irqs disabled, returns true if childs should reap themselves.
444 static int ignoring_children(struct sighand_struct *sigh)
447 spin_lock(&sigh->siglock);
448 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
449 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
450 spin_unlock(&sigh->siglock);
455 * Called with tasklist_lock held for writing.
456 * Unlink a traced task, and clean it up if it was a traced zombie.
457 * Return true if it needs to be reaped with release_task().
458 * (We can't call release_task() here because we already hold tasklist_lock.)
460 * If it's a zombie, our attachedness prevented normal parent notification
461 * or self-reaping. Do notification now if it would have happened earlier.
462 * If it should reap itself, return true.
464 * If it's our own child, there is no notification to do. But if our normal
465 * children self-reap, then this child was prevented by ptrace and we must
466 * reap it now, in that case we must also wake up sub-threads sleeping in
469 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
475 if (p->exit_state != EXIT_ZOMBIE)
478 dead = !thread_group_leader(p);
480 if (!dead && thread_group_empty(p)) {
481 if (!same_thread_group(p->real_parent, tracer))
482 dead = do_notify_parent(p, p->exit_signal);
483 else if (ignoring_children(tracer->sighand)) {
484 __wake_up_parent(p, tracer);
488 /* Mark it as in the process of being reaped. */
490 p->exit_state = EXIT_DEAD;
494 static int ptrace_detach(struct task_struct *child, unsigned int data)
496 if (!valid_signal(data))
499 /* Architecture-specific hardware disable .. */
500 ptrace_disable(child);
502 write_lock_irq(&tasklist_lock);
504 * We rely on ptrace_freeze_traced(). It can't be killed and
505 * untraced by another thread, it can't be a zombie.
507 WARN_ON(!child->ptrace || child->exit_state);
509 * tasklist_lock avoids the race with wait_task_stopped(), see
510 * the comment in ptrace_resume().
512 child->exit_code = data;
513 __ptrace_detach(current, child);
514 write_unlock_irq(&tasklist_lock);
516 proc_ptrace_connector(child, PTRACE_DETACH);
522 * Detach all tasks we were using ptrace on. Called with tasklist held
525 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
527 struct task_struct *p, *n;
529 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
530 if (unlikely(p->ptrace & PT_EXITKILL))
531 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
533 if (__ptrace_detach(tracer, p))
534 list_add(&p->ptrace_entry, dead);
538 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
544 int this_len, retval;
546 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
547 retval = access_process_vm(tsk, src, buf, this_len, FOLL_FORCE);
553 if (copy_to_user(dst, buf, retval))
563 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
569 int this_len, retval;
571 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
572 if (copy_from_user(buf, src, this_len))
574 retval = access_process_vm(tsk, dst, buf, this_len,
575 FOLL_FORCE | FOLL_WRITE);
589 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
593 if (data & ~(unsigned long)PTRACE_O_MASK)
596 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
597 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
598 !IS_ENABLED(CONFIG_SECCOMP))
601 if (!capable(CAP_SYS_ADMIN))
604 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
605 current->ptrace & PT_SUSPEND_SECCOMP)
609 /* Avoid intermediate state when all opts are cleared */
610 flags = child->ptrace;
611 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
612 flags |= (data << PT_OPT_FLAG_SHIFT);
613 child->ptrace = flags;
618 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
623 if (lock_task_sighand(child, &flags)) {
625 if (likely(child->last_siginfo != NULL)) {
626 *info = *child->last_siginfo;
629 unlock_task_sighand(child, &flags);
634 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
639 if (lock_task_sighand(child, &flags)) {
641 if (likely(child->last_siginfo != NULL)) {
642 *child->last_siginfo = *info;
645 unlock_task_sighand(child, &flags);
650 static int ptrace_peek_siginfo(struct task_struct *child,
654 struct ptrace_peeksiginfo_args arg;
655 struct sigpending *pending;
659 ret = copy_from_user(&arg, (void __user *) addr,
660 sizeof(struct ptrace_peeksiginfo_args));
664 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
665 return -EINVAL; /* unknown flags */
670 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
671 pending = &child->signal->shared_pending;
673 pending = &child->pending;
675 for (i = 0; i < arg.nr; ) {
677 s32 off = arg.off + i;
679 spin_lock_irq(&child->sighand->siglock);
680 list_for_each_entry(q, &pending->list, list) {
682 copy_siginfo(&info, &q->info);
686 spin_unlock_irq(&child->sighand->siglock);
688 if (off >= 0) /* beyond the end of the list */
692 if (unlikely(in_compat_syscall())) {
693 compat_siginfo_t __user *uinfo = compat_ptr(data);
695 if (copy_siginfo_to_user32(uinfo, &info) ||
696 __put_user(info.si_code, &uinfo->si_code)) {
704 siginfo_t __user *uinfo = (siginfo_t __user *) data;
706 if (copy_siginfo_to_user(uinfo, &info) ||
707 __put_user(info.si_code, &uinfo->si_code)) {
713 data += sizeof(siginfo_t);
716 if (signal_pending(current))
728 #ifdef PTRACE_SINGLESTEP
729 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
731 #define is_singlestep(request) 0
734 #ifdef PTRACE_SINGLEBLOCK
735 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
737 #define is_singleblock(request) 0
741 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
743 #define is_sysemu_singlestep(request) 0
746 static int ptrace_resume(struct task_struct *child, long request,
751 if (!valid_signal(data))
754 if (request == PTRACE_SYSCALL)
755 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
757 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
759 #ifdef TIF_SYSCALL_EMU
760 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
761 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
763 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
766 if (is_singleblock(request)) {
767 if (unlikely(!arch_has_block_step()))
769 user_enable_block_step(child);
770 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
771 if (unlikely(!arch_has_single_step()))
773 user_enable_single_step(child);
775 user_disable_single_step(child);
779 * Change ->exit_code and ->state under siglock to avoid the race
780 * with wait_task_stopped() in between; a non-zero ->exit_code will
781 * wrongly look like another report from tracee.
783 * Note that we need siglock even if ->exit_code == data and/or this
784 * status was not reported yet, the new status must not be cleared by
785 * wait_task_stopped() after resume.
787 * If data == 0 we do not care if wait_task_stopped() reports the old
788 * status and clears the code too; this can't race with the tracee, it
789 * takes siglock after resume.
791 need_siglock = data && !thread_group_empty(current);
793 spin_lock_irq(&child->sighand->siglock);
794 child->exit_code = data;
795 wake_up_state(child, __TASK_TRACED);
797 spin_unlock_irq(&child->sighand->siglock);
802 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
804 static const struct user_regset *
805 find_regset(const struct user_regset_view *view, unsigned int type)
807 const struct user_regset *regset;
810 for (n = 0; n < view->n; ++n) {
811 regset = view->regsets + n;
812 if (regset->core_note_type == type)
819 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
822 const struct user_regset_view *view = task_user_regset_view(task);
823 const struct user_regset *regset = find_regset(view, type);
826 if (!regset || (kiov->iov_len % regset->size) != 0)
829 regset_no = regset - view->regsets;
830 kiov->iov_len = min(kiov->iov_len,
831 (__kernel_size_t) (regset->n * regset->size));
833 if (req == PTRACE_GETREGSET)
834 return copy_regset_to_user(task, view, regset_no, 0,
835 kiov->iov_len, kiov->iov_base);
837 return copy_regset_from_user(task, view, regset_no, 0,
838 kiov->iov_len, kiov->iov_base);
842 * This is declared in linux/regset.h and defined in machine-dependent
843 * code. We put the export here, near the primary machine-neutral use,
844 * to ensure no machine forgets it.
846 EXPORT_SYMBOL_GPL(task_user_regset_view);
849 int ptrace_request(struct task_struct *child, long request,
850 unsigned long addr, unsigned long data)
852 bool seized = child->ptrace & PT_SEIZED;
854 siginfo_t siginfo, *si;
855 void __user *datavp = (void __user *) data;
856 unsigned long __user *datalp = datavp;
860 case PTRACE_PEEKTEXT:
861 case PTRACE_PEEKDATA:
862 return generic_ptrace_peekdata(child, addr, data);
863 case PTRACE_POKETEXT:
864 case PTRACE_POKEDATA:
865 return generic_ptrace_pokedata(child, addr, data);
867 #ifdef PTRACE_OLDSETOPTIONS
868 case PTRACE_OLDSETOPTIONS:
870 case PTRACE_SETOPTIONS:
871 ret = ptrace_setoptions(child, data);
873 case PTRACE_GETEVENTMSG:
874 ret = put_user(child->ptrace_message, datalp);
877 case PTRACE_PEEKSIGINFO:
878 ret = ptrace_peek_siginfo(child, addr, data);
881 case PTRACE_GETSIGINFO:
882 ret = ptrace_getsiginfo(child, &siginfo);
884 ret = copy_siginfo_to_user(datavp, &siginfo);
887 case PTRACE_SETSIGINFO:
888 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
891 ret = ptrace_setsiginfo(child, &siginfo);
894 case PTRACE_GETSIGMASK:
895 if (addr != sizeof(sigset_t)) {
900 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
907 case PTRACE_SETSIGMASK: {
910 if (addr != sizeof(sigset_t)) {
915 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
920 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
923 * Every thread does recalc_sigpending() after resume, so
924 * retarget_shared_pending() and recalc_sigpending() are not
927 spin_lock_irq(&child->sighand->siglock);
928 child->blocked = new_set;
929 spin_unlock_irq(&child->sighand->siglock);
935 case PTRACE_INTERRUPT:
937 * Stop tracee without any side-effect on signal or job
938 * control. At least one trap is guaranteed to happen
939 * after this request. If @child is already trapped, the
940 * current trap is not disturbed and another trap will
941 * happen after the current trap is ended with PTRACE_CONT.
943 * The actual trap might not be PTRACE_EVENT_STOP trap but
944 * the pending condition is cleared regardless.
946 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
950 * INTERRUPT doesn't disturb existing trap sans one
951 * exception. If ptracer issued LISTEN for the current
952 * STOP, this INTERRUPT should clear LISTEN and re-trap
955 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
956 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
958 unlock_task_sighand(child, &flags);
964 * Listen for events. Tracee must be in STOP. It's not
965 * resumed per-se but is not considered to be in TRACED by
966 * wait(2) or ptrace(2). If an async event (e.g. group
967 * stop state change) happens, tracee will enter STOP trap
968 * again. Alternatively, ptracer can issue INTERRUPT to
969 * finish listening and re-trap tracee into STOP.
971 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
974 si = child->last_siginfo;
975 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
976 child->jobctl |= JOBCTL_LISTENING;
978 * If NOTIFY is set, it means event happened between
979 * start of this trap and now. Trigger re-trap.
981 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
982 ptrace_signal_wake_up(child, true);
985 unlock_task_sighand(child, &flags);
988 case PTRACE_DETACH: /* detach a process that was attached. */
989 ret = ptrace_detach(child, data);
992 #ifdef CONFIG_BINFMT_ELF_FDPIC
993 case PTRACE_GETFDPIC: {
994 struct mm_struct *mm = get_task_mm(child);
995 unsigned long tmp = 0;
1002 case PTRACE_GETFDPIC_EXEC:
1003 tmp = mm->context.exec_fdpic_loadmap;
1005 case PTRACE_GETFDPIC_INTERP:
1006 tmp = mm->context.interp_fdpic_loadmap;
1013 ret = put_user(tmp, datalp);
1018 #ifdef PTRACE_SINGLESTEP
1019 case PTRACE_SINGLESTEP:
1021 #ifdef PTRACE_SINGLEBLOCK
1022 case PTRACE_SINGLEBLOCK:
1024 #ifdef PTRACE_SYSEMU
1026 case PTRACE_SYSEMU_SINGLESTEP:
1028 case PTRACE_SYSCALL:
1030 return ptrace_resume(child, request, data);
1033 if (child->exit_state) /* already dead */
1035 return ptrace_resume(child, request, SIGKILL);
1037 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1038 case PTRACE_GETREGSET:
1039 case PTRACE_SETREGSET: {
1041 struct iovec __user *uiov = datavp;
1043 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1046 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1047 __get_user(kiov.iov_len, &uiov->iov_len))
1050 ret = ptrace_regset(child, request, addr, &kiov);
1052 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1057 case PTRACE_SECCOMP_GET_FILTER:
1058 ret = seccomp_get_filter(child, addr, datavp);
1068 static struct task_struct *ptrace_get_task_struct(pid_t pid)
1070 struct task_struct *child;
1073 child = find_task_by_vpid(pid);
1075 get_task_struct(child);
1079 return ERR_PTR(-ESRCH);
1083 #ifndef arch_ptrace_attach
1084 #define arch_ptrace_attach(child) do { } while (0)
1087 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1088 unsigned long, data)
1090 struct task_struct *child;
1093 if (request == PTRACE_TRACEME) {
1094 ret = ptrace_traceme();
1096 arch_ptrace_attach(current);
1100 child = ptrace_get_task_struct(pid);
1101 if (IS_ERR(child)) {
1102 ret = PTR_ERR(child);
1106 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1107 ret = ptrace_attach(child, request, addr, data);
1109 * Some architectures need to do book-keeping after
1113 arch_ptrace_attach(child);
1114 goto out_put_task_struct;
1117 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1118 request == PTRACE_INTERRUPT);
1120 goto out_put_task_struct;
1122 ret = arch_ptrace(child, request, addr, data);
1123 if (ret || request != PTRACE_DETACH)
1124 ptrace_unfreeze_traced(child);
1126 out_put_task_struct:
1127 put_task_struct(child);
1132 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1138 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1139 if (copied != sizeof(tmp))
1141 return put_user(tmp, (unsigned long __user *)data);
1144 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1149 copied = access_process_vm(tsk, addr, &data, sizeof(data),
1150 FOLL_FORCE | FOLL_WRITE);
1151 return (copied == sizeof(data)) ? 0 : -EIO;
1154 #if defined CONFIG_COMPAT
1156 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1157 compat_ulong_t addr, compat_ulong_t data)
1159 compat_ulong_t __user *datap = compat_ptr(data);
1160 compat_ulong_t word;
1165 case PTRACE_PEEKTEXT:
1166 case PTRACE_PEEKDATA:
1167 ret = access_process_vm(child, addr, &word, sizeof(word),
1169 if (ret != sizeof(word))
1172 ret = put_user(word, datap);
1175 case PTRACE_POKETEXT:
1176 case PTRACE_POKEDATA:
1177 ret = access_process_vm(child, addr, &data, sizeof(data),
1178 FOLL_FORCE | FOLL_WRITE);
1179 ret = (ret != sizeof(data) ? -EIO : 0);
1182 case PTRACE_GETEVENTMSG:
1183 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1186 case PTRACE_GETSIGINFO:
1187 ret = ptrace_getsiginfo(child, &siginfo);
1189 ret = copy_siginfo_to_user32(
1190 (struct compat_siginfo __user *) datap,
1194 case PTRACE_SETSIGINFO:
1195 memset(&siginfo, 0, sizeof siginfo);
1196 if (copy_siginfo_from_user32(
1197 &siginfo, (struct compat_siginfo __user *) datap))
1200 ret = ptrace_setsiginfo(child, &siginfo);
1202 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1203 case PTRACE_GETREGSET:
1204 case PTRACE_SETREGSET:
1207 struct compat_iovec __user *uiov =
1208 (struct compat_iovec __user *) datap;
1212 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1215 if (__get_user(ptr, &uiov->iov_base) ||
1216 __get_user(len, &uiov->iov_len))
1219 kiov.iov_base = compat_ptr(ptr);
1222 ret = ptrace_regset(child, request, addr, &kiov);
1224 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1230 ret = ptrace_request(child, request, addr, data);
1236 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1237 compat_long_t, addr, compat_long_t, data)
1239 struct task_struct *child;
1242 if (request == PTRACE_TRACEME) {
1243 ret = ptrace_traceme();
1247 child = ptrace_get_task_struct(pid);
1248 if (IS_ERR(child)) {
1249 ret = PTR_ERR(child);
1253 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1254 ret = ptrace_attach(child, request, addr, data);
1256 * Some architectures need to do book-keeping after
1260 arch_ptrace_attach(child);
1261 goto out_put_task_struct;
1264 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1265 request == PTRACE_INTERRUPT);
1267 ret = compat_arch_ptrace(child, request, addr, data);
1268 if (ret || request != PTRACE_DETACH)
1269 ptrace_unfreeze_traced(child);
1272 out_put_task_struct:
1273 put_task_struct(child);
1277 #endif /* CONFIG_COMPAT */