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>
31 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
32 const struct cred *ptracer_cred)
34 BUG_ON(!list_empty(&child->ptrace_entry));
35 list_add(&child->ptrace_entry, &new_parent->ptraced);
36 child->parent = new_parent;
37 child->ptracer_cred = get_cred(ptracer_cred);
41 * ptrace a task: make the debugger its new parent and
42 * move it to the ptrace list.
44 * Must be called with the tasklist lock write-held.
46 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
48 __ptrace_link(child, new_parent, current_cred());
52 * __ptrace_unlink - unlink ptracee and restore its execution state
53 * @child: ptracee to be unlinked
55 * Remove @child from the ptrace list, move it back to the original parent,
56 * and restore the execution state so that it conforms to the group stop
59 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
60 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
61 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
62 * If the ptracer is exiting, the ptracee can be in any state.
64 * After detach, the ptracee should be in a state which conforms to the
65 * group stop. If the group is stopped or in the process of stopping, the
66 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
67 * up from TASK_TRACED.
69 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
70 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
71 * to but in the opposite direction of what happens while attaching to a
72 * stopped task. However, in this direction, the intermediate RUNNING
73 * state is not hidden even from the current ptracer and if it immediately
74 * re-attaches and performs a WNOHANG wait(2), it may fail.
77 * write_lock_irq(tasklist_lock)
79 void __ptrace_unlink(struct task_struct *child)
81 const struct cred *old_cred;
82 BUG_ON(!child->ptrace);
85 child->parent = child->real_parent;
86 list_del_init(&child->ptrace_entry);
87 old_cred = child->ptracer_cred;
88 child->ptracer_cred = NULL;
91 spin_lock(&child->sighand->siglock);
94 * Clear all pending traps and TRAPPING. TRAPPING should be
95 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
97 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
98 task_clear_jobctl_trapping(child);
101 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
104 if (!(child->flags & PF_EXITING) &&
105 (child->signal->flags & SIGNAL_STOP_STOPPED ||
106 child->signal->group_stop_count)) {
107 child->jobctl |= JOBCTL_STOP_PENDING;
110 * This is only possible if this thread was cloned by the
111 * traced task running in the stopped group, set the signal
112 * for the future reports.
113 * FIXME: we should change ptrace_init_task() to handle this
116 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
117 child->jobctl |= SIGSTOP;
121 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
122 * @child in the butt. Note that @resume should be used iff @child
123 * is in TASK_TRACED; otherwise, we might unduly disrupt
124 * TASK_KILLABLE sleeps.
126 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
127 ptrace_signal_wake_up(child, true);
129 spin_unlock(&child->sighand->siglock);
132 static bool looks_like_a_spurious_pid(struct task_struct *task)
134 if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
137 if (task_pid_vnr(task) == task->ptrace_message)
140 * The tracee changed its pid but the PTRACE_EVENT_EXEC event
141 * was not wait()'ed, most probably debugger targets the old
142 * leader which was destroyed in de_thread().
147 /* Ensure that nothing can wake it up, even SIGKILL */
148 static bool ptrace_freeze_traced(struct task_struct *task)
152 /* Lockless, nobody but us can set this flag */
153 if (task->jobctl & JOBCTL_LISTENING)
156 spin_lock_irq(&task->sighand->siglock);
157 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
158 !__fatal_signal_pending(task)) {
159 task->state = __TASK_TRACED;
162 spin_unlock_irq(&task->sighand->siglock);
167 static void ptrace_unfreeze_traced(struct task_struct *task)
169 if (task->state != __TASK_TRACED)
172 WARN_ON(!task->ptrace || task->parent != current);
175 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
176 * Recheck state under the lock to close this race.
178 spin_lock_irq(&task->sighand->siglock);
179 if (task->state == __TASK_TRACED) {
180 if (__fatal_signal_pending(task))
181 wake_up_state(task, __TASK_TRACED);
183 task->state = TASK_TRACED;
185 spin_unlock_irq(&task->sighand->siglock);
189 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
190 * @child: ptracee to check for
191 * @ignore_state: don't check whether @child is currently %TASK_TRACED
193 * Check whether @child is being ptraced by %current and ready for further
194 * ptrace operations. If @ignore_state is %false, @child also should be in
195 * %TASK_TRACED state and on return the child is guaranteed to be traced
196 * and not executing. If @ignore_state is %true, @child can be in any
200 * Grabs and releases tasklist_lock and @child->sighand->siglock.
203 * 0 on success, -ESRCH if %child is not ready.
205 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
210 * We take the read lock around doing both checks to close a
211 * possible race where someone else was tracing our child and
212 * detached between these two checks. After this locked check,
213 * we are sure that this is our traced child and that can only
214 * be changed by us so it's not changing right after this.
216 read_lock(&tasklist_lock);
217 if (child->ptrace && child->parent == current) {
218 WARN_ON(child->state == __TASK_TRACED);
220 * child->sighand can't be NULL, release_task()
221 * does ptrace_unlink() before __exit_signal().
223 if (ignore_state || ptrace_freeze_traced(child))
226 read_unlock(&tasklist_lock);
228 if (!ret && !ignore_state) {
229 if (!wait_task_inactive(child, __TASK_TRACED)) {
231 * This can only happen if may_ptrace_stop() fails and
232 * ptrace_stop() changes ->state back to TASK_RUNNING,
233 * so we should not worry about leaking __TASK_TRACED.
235 WARN_ON(child->state == __TASK_TRACED);
243 static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
245 if (mode & PTRACE_MODE_SCHED)
248 if (mode & PTRACE_MODE_NOAUDIT)
249 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
251 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
254 /* Returns 0 on success, -errno on denial. */
255 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
257 const struct cred *cred = current_cred(), *tcred;
258 struct mm_struct *mm;
262 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
263 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
267 /* May we inspect the given task?
268 * This check is used both for attaching with ptrace
269 * and for allowing access to sensitive information in /proc.
271 * ptrace_attach denies several cases that /proc allows
272 * because setting up the necessary parent/child relationship
273 * or halting the specified task is impossible.
276 /* Don't let security modules deny introspection */
277 if (same_thread_group(task, current))
280 if (mode & PTRACE_MODE_FSCREDS) {
281 caller_uid = cred->fsuid;
282 caller_gid = cred->fsgid;
285 * Using the euid would make more sense here, but something
286 * in userland might rely on the old behavior, and this
287 * shouldn't be a security problem since
288 * PTRACE_MODE_REALCREDS implies that the caller explicitly
289 * used a syscall that requests access to another process
290 * (and not a filesystem syscall to procfs).
292 caller_uid = cred->uid;
293 caller_gid = cred->gid;
295 tcred = __task_cred(task);
296 if (uid_eq(caller_uid, tcred->euid) &&
297 uid_eq(caller_uid, tcred->suid) &&
298 uid_eq(caller_uid, tcred->uid) &&
299 gid_eq(caller_gid, tcred->egid) &&
300 gid_eq(caller_gid, tcred->sgid) &&
301 gid_eq(caller_gid, tcred->gid))
303 if (ptrace_has_cap(tcred->user_ns, mode))
310 * If a task drops privileges and becomes nondumpable (through a syscall
311 * like setresuid()) while we are trying to access it, we must ensure
312 * that the dumpability is read after the credentials; otherwise,
313 * we may be able to attach to a task that we shouldn't be able to
314 * attach to (as if the task had dropped privileges without becoming
316 * Pairs with a write barrier in commit_creds().
321 ((get_dumpable(mm) != SUID_DUMP_USER) &&
322 !ptrace_has_cap(mm->user_ns, mode)))
325 if (mode & PTRACE_MODE_SCHED)
327 return security_ptrace_access_check(task, mode);
330 bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode)
332 return __ptrace_may_access(task, mode | PTRACE_MODE_SCHED);
335 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
339 err = __ptrace_may_access(task, mode);
344 static int ptrace_attach(struct task_struct *task, long request,
348 bool seize = (request == PTRACE_SEIZE);
355 if (flags & ~(unsigned long)PTRACE_O_MASK)
357 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
365 if (unlikely(task->flags & PF_KTHREAD))
367 if (same_thread_group(task, current))
371 * Protect exec's credential calculations against our interference;
372 * SUID, SGID and LSM creds get determined differently
375 retval = -ERESTARTNOINTR;
376 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
380 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
385 write_lock_irq(&tasklist_lock);
387 if (unlikely(task->exit_state))
388 goto unlock_tasklist;
390 goto unlock_tasklist;
394 task->ptrace = flags;
396 ptrace_link(task, current);
398 /* SEIZE doesn't trap tracee on attach */
400 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
402 spin_lock(&task->sighand->siglock);
405 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
406 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
407 * will be cleared if the child completes the transition or any
408 * event which clears the group stop states happens. We'll wait
409 * for the transition to complete before returning from this
412 * This hides STOPPED -> RUNNING -> TRACED transition from the
413 * attaching thread but a different thread in the same group can
414 * still observe the transient RUNNING state. IOW, if another
415 * thread's WNOHANG wait(2) on the stopped tracee races against
416 * ATTACH, the wait(2) may fail due to the transient RUNNING.
418 * The following task_is_stopped() test is safe as both transitions
419 * in and out of STOPPED are protected by siglock.
421 if (task_is_stopped(task) &&
422 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
423 signal_wake_up_state(task, __TASK_STOPPED);
425 spin_unlock(&task->sighand->siglock);
429 write_unlock_irq(&tasklist_lock);
431 mutex_unlock(&task->signal->cred_guard_mutex);
434 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
435 TASK_UNINTERRUPTIBLE);
436 proc_ptrace_connector(task, PTRACE_ATTACH);
443 * ptrace_traceme -- helper for PTRACE_TRACEME
445 * Performs checks and sets PT_PTRACED.
446 * Should be used by all ptrace implementations for PTRACE_TRACEME.
448 static int ptrace_traceme(void)
452 write_lock_irq(&tasklist_lock);
453 /* Are we already being traced? */
454 if (!current->ptrace) {
455 ret = security_ptrace_traceme(current->parent);
457 * Check PF_EXITING to ensure ->real_parent has not passed
458 * exit_ptrace(). Otherwise we don't report the error but
459 * pretend ->real_parent untraces us right after return.
461 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
462 current->ptrace = PT_PTRACED;
463 ptrace_link(current, current->real_parent);
466 write_unlock_irq(&tasklist_lock);
472 * Called with irqs disabled, returns true if childs should reap themselves.
474 static int ignoring_children(struct sighand_struct *sigh)
477 spin_lock(&sigh->siglock);
478 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
479 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
480 spin_unlock(&sigh->siglock);
485 * Called with tasklist_lock held for writing.
486 * Unlink a traced task, and clean it up if it was a traced zombie.
487 * Return true if it needs to be reaped with release_task().
488 * (We can't call release_task() here because we already hold tasklist_lock.)
490 * If it's a zombie, our attachedness prevented normal parent notification
491 * or self-reaping. Do notification now if it would have happened earlier.
492 * If it should reap itself, return true.
494 * If it's our own child, there is no notification to do. But if our normal
495 * children self-reap, then this child was prevented by ptrace and we must
496 * reap it now, in that case we must also wake up sub-threads sleeping in
499 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
505 if (p->exit_state != EXIT_ZOMBIE)
508 dead = !thread_group_leader(p);
510 if (!dead && thread_group_empty(p)) {
511 if (!same_thread_group(p->real_parent, tracer))
512 dead = do_notify_parent(p, p->exit_signal);
513 else if (ignoring_children(tracer->sighand)) {
514 __wake_up_parent(p, tracer);
518 /* Mark it as in the process of being reaped. */
520 p->exit_state = EXIT_DEAD;
524 static int ptrace_detach(struct task_struct *child, unsigned int data)
526 if (!valid_signal(data))
529 /* Architecture-specific hardware disable .. */
530 ptrace_disable(child);
531 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
533 write_lock_irq(&tasklist_lock);
535 * We rely on ptrace_freeze_traced(). It can't be killed and
536 * untraced by another thread, it can't be a zombie.
538 WARN_ON(!child->ptrace || child->exit_state);
540 * tasklist_lock avoids the race with wait_task_stopped(), see
541 * the comment in ptrace_resume().
543 child->exit_code = data;
544 __ptrace_detach(current, child);
545 write_unlock_irq(&tasklist_lock);
547 proc_ptrace_connector(child, PTRACE_DETACH);
553 * Detach all tasks we were using ptrace on. Called with tasklist held
556 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
558 struct task_struct *p, *n;
560 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
561 if (unlikely(p->ptrace & PT_EXITKILL))
562 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
564 if (__ptrace_detach(tracer, p))
565 list_add(&p->ptrace_entry, dead);
569 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
575 int this_len, retval;
577 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
578 retval = access_process_vm(tsk, src, buf, this_len, 0);
584 if (copy_to_user(dst, buf, retval))
594 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
600 int this_len, retval;
602 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
603 if (copy_from_user(buf, src, this_len))
605 retval = access_process_vm(tsk, dst, buf, this_len, 1);
619 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
623 if (data & ~(unsigned long)PTRACE_O_MASK)
626 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
627 if (!config_enabled(CONFIG_CHECKPOINT_RESTORE) ||
628 !config_enabled(CONFIG_SECCOMP))
631 if (!capable(CAP_SYS_ADMIN))
634 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
635 current->ptrace & PT_SUSPEND_SECCOMP)
639 /* Avoid intermediate state when all opts are cleared */
640 flags = child->ptrace;
641 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
642 flags |= (data << PT_OPT_FLAG_SHIFT);
643 child->ptrace = flags;
648 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
653 if (lock_task_sighand(child, &flags)) {
655 if (likely(child->last_siginfo != NULL)) {
656 *info = *child->last_siginfo;
659 unlock_task_sighand(child, &flags);
664 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
669 if (lock_task_sighand(child, &flags)) {
671 if (likely(child->last_siginfo != NULL)) {
672 *child->last_siginfo = *info;
675 unlock_task_sighand(child, &flags);
680 static int ptrace_peek_siginfo(struct task_struct *child,
684 struct ptrace_peeksiginfo_args arg;
685 struct sigpending *pending;
689 ret = copy_from_user(&arg, (void __user *) addr,
690 sizeof(struct ptrace_peeksiginfo_args));
694 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
695 return -EINVAL; /* unknown flags */
700 /* Ensure arg.off fits in an unsigned long */
701 if (arg.off > ULONG_MAX)
704 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
705 pending = &child->signal->shared_pending;
707 pending = &child->pending;
709 for (i = 0; i < arg.nr; ) {
711 unsigned long off = arg.off + i;
714 spin_lock_irq(&child->sighand->siglock);
715 list_for_each_entry(q, &pending->list, list) {
718 copy_siginfo(&info, &q->info);
722 spin_unlock_irq(&child->sighand->siglock);
724 if (!found) /* beyond the end of the list */
728 if (unlikely(is_compat_task())) {
729 compat_siginfo_t __user *uinfo = compat_ptr(data);
731 if (copy_siginfo_to_user32(uinfo, &info) ||
732 __put_user(info.si_code, &uinfo->si_code)) {
740 siginfo_t __user *uinfo = (siginfo_t __user *) data;
742 if (copy_siginfo_to_user(uinfo, &info) ||
743 __put_user(info.si_code, &uinfo->si_code)) {
749 data += sizeof(siginfo_t);
752 if (signal_pending(current))
764 #ifdef PTRACE_SINGLESTEP
765 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
767 #define is_singlestep(request) 0
770 #ifdef PTRACE_SINGLEBLOCK
771 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
773 #define is_singleblock(request) 0
777 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
779 #define is_sysemu_singlestep(request) 0
782 static int ptrace_resume(struct task_struct *child, long request,
787 if (!valid_signal(data))
790 if (request == PTRACE_SYSCALL)
791 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
793 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
795 #ifdef TIF_SYSCALL_EMU
796 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
797 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
799 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
802 if (is_singleblock(request)) {
803 if (unlikely(!arch_has_block_step()))
805 user_enable_block_step(child);
806 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
807 if (unlikely(!arch_has_single_step()))
809 user_enable_single_step(child);
811 user_disable_single_step(child);
815 * Change ->exit_code and ->state under siglock to avoid the race
816 * with wait_task_stopped() in between; a non-zero ->exit_code will
817 * wrongly look like another report from tracee.
819 * Note that we need siglock even if ->exit_code == data and/or this
820 * status was not reported yet, the new status must not be cleared by
821 * wait_task_stopped() after resume.
823 * If data == 0 we do not care if wait_task_stopped() reports the old
824 * status and clears the code too; this can't race with the tracee, it
825 * takes siglock after resume.
827 need_siglock = data && !thread_group_empty(current);
829 spin_lock_irq(&child->sighand->siglock);
830 child->exit_code = data;
831 wake_up_state(child, __TASK_TRACED);
833 spin_unlock_irq(&child->sighand->siglock);
838 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
840 static const struct user_regset *
841 find_regset(const struct user_regset_view *view, unsigned int type)
843 const struct user_regset *regset;
846 for (n = 0; n < view->n; ++n) {
847 regset = view->regsets + n;
848 if (regset->core_note_type == type)
855 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
858 const struct user_regset_view *view = task_user_regset_view(task);
859 const struct user_regset *regset = find_regset(view, type);
862 if (!regset || (kiov->iov_len % regset->size) != 0)
865 regset_no = regset - view->regsets;
866 kiov->iov_len = min(kiov->iov_len,
867 (__kernel_size_t) (regset->n * regset->size));
869 if (req == PTRACE_GETREGSET)
870 return copy_regset_to_user(task, view, regset_no, 0,
871 kiov->iov_len, kiov->iov_base);
873 return copy_regset_from_user(task, view, regset_no, 0,
874 kiov->iov_len, kiov->iov_base);
878 * This is declared in linux/regset.h and defined in machine-dependent
879 * code. We put the export here, near the primary machine-neutral use,
880 * to ensure no machine forgets it.
882 EXPORT_SYMBOL_GPL(task_user_regset_view);
885 int ptrace_request(struct task_struct *child, long request,
886 unsigned long addr, unsigned long data)
888 bool seized = child->ptrace & PT_SEIZED;
890 siginfo_t siginfo, *si;
891 void __user *datavp = (void __user *) data;
892 unsigned long __user *datalp = datavp;
896 case PTRACE_PEEKTEXT:
897 case PTRACE_PEEKDATA:
898 return generic_ptrace_peekdata(child, addr, data);
899 case PTRACE_POKETEXT:
900 case PTRACE_POKEDATA:
901 return generic_ptrace_pokedata(child, addr, data);
903 #ifdef PTRACE_OLDSETOPTIONS
904 case PTRACE_OLDSETOPTIONS:
906 case PTRACE_SETOPTIONS:
907 ret = ptrace_setoptions(child, data);
909 case PTRACE_GETEVENTMSG:
910 ret = put_user(child->ptrace_message, datalp);
913 case PTRACE_PEEKSIGINFO:
914 ret = ptrace_peek_siginfo(child, addr, data);
917 case PTRACE_GETSIGINFO:
918 ret = ptrace_getsiginfo(child, &siginfo);
920 ret = copy_siginfo_to_user(datavp, &siginfo);
923 case PTRACE_SETSIGINFO:
924 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
927 ret = ptrace_setsiginfo(child, &siginfo);
930 case PTRACE_GETSIGMASK:
931 if (addr != sizeof(sigset_t)) {
936 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
943 case PTRACE_SETSIGMASK: {
946 if (addr != sizeof(sigset_t)) {
951 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
956 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
959 * Every thread does recalc_sigpending() after resume, so
960 * retarget_shared_pending() and recalc_sigpending() are not
963 spin_lock_irq(&child->sighand->siglock);
964 child->blocked = new_set;
965 spin_unlock_irq(&child->sighand->siglock);
971 case PTRACE_INTERRUPT:
973 * Stop tracee without any side-effect on signal or job
974 * control. At least one trap is guaranteed to happen
975 * after this request. If @child is already trapped, the
976 * current trap is not disturbed and another trap will
977 * happen after the current trap is ended with PTRACE_CONT.
979 * The actual trap might not be PTRACE_EVENT_STOP trap but
980 * the pending condition is cleared regardless.
982 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
986 * INTERRUPT doesn't disturb existing trap sans one
987 * exception. If ptracer issued LISTEN for the current
988 * STOP, this INTERRUPT should clear LISTEN and re-trap
991 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
992 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
994 unlock_task_sighand(child, &flags);
1000 * Listen for events. Tracee must be in STOP. It's not
1001 * resumed per-se but is not considered to be in TRACED by
1002 * wait(2) or ptrace(2). If an async event (e.g. group
1003 * stop state change) happens, tracee will enter STOP trap
1004 * again. Alternatively, ptracer can issue INTERRUPT to
1005 * finish listening and re-trap tracee into STOP.
1007 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1010 si = child->last_siginfo;
1011 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1012 child->jobctl |= JOBCTL_LISTENING;
1014 * If NOTIFY is set, it means event happened between
1015 * start of this trap and now. Trigger re-trap.
1017 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1018 ptrace_signal_wake_up(child, true);
1021 unlock_task_sighand(child, &flags);
1024 case PTRACE_DETACH: /* detach a process that was attached. */
1025 ret = ptrace_detach(child, data);
1028 #ifdef CONFIG_BINFMT_ELF_FDPIC
1029 case PTRACE_GETFDPIC: {
1030 struct mm_struct *mm = get_task_mm(child);
1031 unsigned long tmp = 0;
1038 case PTRACE_GETFDPIC_EXEC:
1039 tmp = mm->context.exec_fdpic_loadmap;
1041 case PTRACE_GETFDPIC_INTERP:
1042 tmp = mm->context.interp_fdpic_loadmap;
1049 ret = put_user(tmp, datalp);
1054 #ifdef PTRACE_SINGLESTEP
1055 case PTRACE_SINGLESTEP:
1057 #ifdef PTRACE_SINGLEBLOCK
1058 case PTRACE_SINGLEBLOCK:
1060 #ifdef PTRACE_SYSEMU
1062 case PTRACE_SYSEMU_SINGLESTEP:
1064 case PTRACE_SYSCALL:
1066 return ptrace_resume(child, request, data);
1069 if (child->exit_state) /* already dead */
1071 return ptrace_resume(child, request, SIGKILL);
1073 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1074 case PTRACE_GETREGSET:
1075 case PTRACE_SETREGSET: {
1077 struct iovec __user *uiov = datavp;
1079 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1082 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1083 __get_user(kiov.iov_len, &uiov->iov_len))
1086 ret = ptrace_regset(child, request, addr, &kiov);
1088 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1093 case PTRACE_SECCOMP_GET_FILTER:
1094 ret = seccomp_get_filter(child, addr, datavp);
1104 static struct task_struct *ptrace_get_task_struct(pid_t pid)
1106 struct task_struct *child;
1109 child = find_task_by_vpid(pid);
1111 get_task_struct(child);
1115 return ERR_PTR(-ESRCH);
1119 #ifndef arch_ptrace_attach
1120 #define arch_ptrace_attach(child) do { } while (0)
1123 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1124 unsigned long, data)
1126 struct task_struct *child;
1129 if (request == PTRACE_TRACEME) {
1130 ret = ptrace_traceme();
1132 arch_ptrace_attach(current);
1136 child = ptrace_get_task_struct(pid);
1137 if (IS_ERR(child)) {
1138 ret = PTR_ERR(child);
1142 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1143 ret = ptrace_attach(child, request, addr, data);
1145 * Some architectures need to do book-keeping after
1149 arch_ptrace_attach(child);
1150 goto out_put_task_struct;
1153 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1154 request == PTRACE_INTERRUPT);
1156 goto out_put_task_struct;
1158 ret = arch_ptrace(child, request, addr, data);
1159 if (ret || request != PTRACE_DETACH)
1160 ptrace_unfreeze_traced(child);
1162 out_put_task_struct:
1163 put_task_struct(child);
1168 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1174 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1175 if (copied != sizeof(tmp))
1177 return put_user(tmp, (unsigned long __user *)data);
1180 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1185 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1186 return (copied == sizeof(data)) ? 0 : -EIO;
1189 #if defined CONFIG_COMPAT
1191 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1192 compat_ulong_t addr, compat_ulong_t data)
1194 compat_ulong_t __user *datap = compat_ptr(data);
1195 compat_ulong_t word;
1200 case PTRACE_PEEKTEXT:
1201 case PTRACE_PEEKDATA:
1202 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1203 if (ret != sizeof(word))
1206 ret = put_user(word, datap);
1209 case PTRACE_POKETEXT:
1210 case PTRACE_POKEDATA:
1211 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1212 ret = (ret != sizeof(data) ? -EIO : 0);
1215 case PTRACE_GETEVENTMSG:
1216 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1219 case PTRACE_GETSIGINFO:
1220 ret = ptrace_getsiginfo(child, &siginfo);
1222 ret = copy_siginfo_to_user32(
1223 (struct compat_siginfo __user *) datap,
1227 case PTRACE_SETSIGINFO:
1228 memset(&siginfo, 0, sizeof siginfo);
1229 if (copy_siginfo_from_user32(
1230 &siginfo, (struct compat_siginfo __user *) datap))
1233 ret = ptrace_setsiginfo(child, &siginfo);
1235 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1236 case PTRACE_GETREGSET:
1237 case PTRACE_SETREGSET:
1240 struct compat_iovec __user *uiov =
1241 (struct compat_iovec __user *) datap;
1245 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1248 if (__get_user(ptr, &uiov->iov_base) ||
1249 __get_user(len, &uiov->iov_len))
1252 kiov.iov_base = compat_ptr(ptr);
1255 ret = ptrace_regset(child, request, addr, &kiov);
1257 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1263 ret = ptrace_request(child, request, addr, data);
1269 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1270 compat_long_t, addr, compat_long_t, data)
1272 struct task_struct *child;
1275 if (request == PTRACE_TRACEME) {
1276 ret = ptrace_traceme();
1280 child = ptrace_get_task_struct(pid);
1281 if (IS_ERR(child)) {
1282 ret = PTR_ERR(child);
1286 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1287 ret = ptrace_attach(child, request, addr, data);
1289 * Some architectures need to do book-keeping after
1293 arch_ptrace_attach(child);
1294 goto out_put_task_struct;
1297 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1298 request == PTRACE_INTERRUPT);
1300 ret = compat_arch_ptrace(child, request, addr, data);
1301 if (ret || request != PTRACE_DETACH)
1302 ptrace_unfreeze_traced(child);
1305 out_put_task_struct:
1306 put_task_struct(child);
1310 #endif /* CONFIG_COMPAT */