1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/ptrace.c
5 * (C) Copyright 1999 Linus Torvalds
7 * Common interfaces for "ptrace()" which we do not want
8 * to continually duplicate across every architecture.
11 #include <linux/capability.h>
12 #include <linux/export.h>
13 #include <linux/sched.h>
14 #include <linux/sched/mm.h>
15 #include <linux/sched/coredump.h>
16 #include <linux/sched/task.h>
17 #include <linux/errno.h>
19 #include <linux/highmem.h>
20 #include <linux/pagemap.h>
21 #include <linux/ptrace.h>
22 #include <linux/security.h>
23 #include <linux/signal.h>
24 #include <linux/uio.h>
25 #include <linux/audit.h>
26 #include <linux/pid_namespace.h>
27 #include <linux/syscalls.h>
28 #include <linux/uaccess.h>
29 #include <linux/regset.h>
30 #include <linux/hw_breakpoint.h>
31 #include <linux/cn_proc.h>
32 #include <linux/compat.h>
33 #include <linux/sched/signal.h>
35 #include <asm/syscall.h> /* for syscall_get_* */
38 * Access another process' address space via ptrace.
39 * Source/target buffer must be kernel space,
40 * Do not walk the page table directly, use get_user_pages
42 int ptrace_access_vm(struct task_struct *tsk, unsigned long addr,
43 void *buf, int len, unsigned int gup_flags)
48 mm = get_task_mm(tsk);
53 (current != tsk->parent) ||
54 ((get_dumpable(mm) != SUID_DUMP_USER) &&
55 !ptracer_capable(tsk, mm->user_ns))) {
60 ret = __access_remote_vm(tsk, mm, addr, buf, len, gup_flags);
67 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent,
68 const struct cred *ptracer_cred)
70 BUG_ON(!list_empty(&child->ptrace_entry));
71 list_add(&child->ptrace_entry, &new_parent->ptraced);
72 child->parent = new_parent;
73 child->ptracer_cred = get_cred(ptracer_cred);
77 * ptrace a task: make the debugger its new parent and
78 * move it to the ptrace list.
80 * Must be called with the tasklist lock write-held.
82 static void ptrace_link(struct task_struct *child, struct task_struct *new_parent)
84 __ptrace_link(child, new_parent, current_cred());
88 * __ptrace_unlink - unlink ptracee and restore its execution state
89 * @child: ptracee to be unlinked
91 * Remove @child from the ptrace list, move it back to the original parent,
92 * and restore the execution state so that it conforms to the group stop
95 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
96 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
97 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
98 * If the ptracer is exiting, the ptracee can be in any state.
100 * After detach, the ptracee should be in a state which conforms to the
101 * group stop. If the group is stopped or in the process of stopping, the
102 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
103 * up from TASK_TRACED.
105 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
106 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
107 * to but in the opposite direction of what happens while attaching to a
108 * stopped task. However, in this direction, the intermediate RUNNING
109 * state is not hidden even from the current ptracer and if it immediately
110 * re-attaches and performs a WNOHANG wait(2), it may fail.
113 * write_lock_irq(tasklist_lock)
115 void __ptrace_unlink(struct task_struct *child)
117 const struct cred *old_cred;
118 BUG_ON(!child->ptrace);
120 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
121 #ifdef TIF_SYSCALL_EMU
122 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
125 child->parent = child->real_parent;
126 list_del_init(&child->ptrace_entry);
127 old_cred = child->ptracer_cred;
128 child->ptracer_cred = NULL;
131 spin_lock(&child->sighand->siglock);
134 * Clear all pending traps and TRAPPING. TRAPPING should be
135 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
137 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
138 task_clear_jobctl_trapping(child);
141 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
144 if (!(child->flags & PF_EXITING) &&
145 (child->signal->flags & SIGNAL_STOP_STOPPED ||
146 child->signal->group_stop_count)) {
147 child->jobctl |= JOBCTL_STOP_PENDING;
150 * This is only possible if this thread was cloned by the
151 * traced task running in the stopped group, set the signal
152 * for the future reports.
153 * FIXME: we should change ptrace_init_task() to handle this
156 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
157 child->jobctl |= SIGSTOP;
161 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
162 * @child in the butt. Note that @resume should be used iff @child
163 * is in TASK_TRACED; otherwise, we might unduly disrupt
164 * TASK_KILLABLE sleeps.
166 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
167 ptrace_signal_wake_up(child, true);
169 spin_unlock(&child->sighand->siglock);
172 static bool looks_like_a_spurious_pid(struct task_struct *task)
174 if (task->exit_code != ((PTRACE_EVENT_EXEC << 8) | SIGTRAP))
177 if (task_pid_vnr(task) == task->ptrace_message)
180 * The tracee changed its pid but the PTRACE_EVENT_EXEC event
181 * was not wait()'ed, most probably debugger targets the old
182 * leader which was destroyed in de_thread().
187 /* Ensure that nothing can wake it up, even SIGKILL */
188 static bool ptrace_freeze_traced(struct task_struct *task)
192 /* Lockless, nobody but us can set this flag */
193 if (task->jobctl & JOBCTL_LISTENING)
196 spin_lock_irq(&task->sighand->siglock);
197 if (task_is_traced(task) && !looks_like_a_spurious_pid(task) &&
198 !__fatal_signal_pending(task)) {
199 task->state = __TASK_TRACED;
202 spin_unlock_irq(&task->sighand->siglock);
207 static void ptrace_unfreeze_traced(struct task_struct *task)
209 if (task->state != __TASK_TRACED)
212 WARN_ON(!task->ptrace || task->parent != current);
215 * PTRACE_LISTEN can allow ptrace_trap_notify to wake us up remotely.
216 * Recheck state under the lock to close this race.
218 spin_lock_irq(&task->sighand->siglock);
219 if (task->state == __TASK_TRACED) {
220 if (__fatal_signal_pending(task))
221 wake_up_state(task, __TASK_TRACED);
223 task->state = TASK_TRACED;
225 spin_unlock_irq(&task->sighand->siglock);
229 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
230 * @child: ptracee to check for
231 * @ignore_state: don't check whether @child is currently %TASK_TRACED
233 * Check whether @child is being ptraced by %current and ready for further
234 * ptrace operations. If @ignore_state is %false, @child also should be in
235 * %TASK_TRACED state and on return the child is guaranteed to be traced
236 * and not executing. If @ignore_state is %true, @child can be in any
240 * Grabs and releases tasklist_lock and @child->sighand->siglock.
243 * 0 on success, -ESRCH if %child is not ready.
245 static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
250 * We take the read lock around doing both checks to close a
251 * possible race where someone else was tracing our child and
252 * detached between these two checks. After this locked check,
253 * we are sure that this is our traced child and that can only
254 * be changed by us so it's not changing right after this.
256 read_lock(&tasklist_lock);
257 if (child->ptrace && child->parent == current) {
258 WARN_ON(child->state == __TASK_TRACED);
260 * child->sighand can't be NULL, release_task()
261 * does ptrace_unlink() before __exit_signal().
263 if (ignore_state || ptrace_freeze_traced(child))
266 read_unlock(&tasklist_lock);
268 if (!ret && !ignore_state) {
269 if (!wait_task_inactive(child, __TASK_TRACED)) {
271 * This can only happen if may_ptrace_stop() fails and
272 * ptrace_stop() changes ->state back to TASK_RUNNING,
273 * so we should not worry about leaking __TASK_TRACED.
275 WARN_ON(child->state == __TASK_TRACED);
283 static bool ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
285 if (mode & PTRACE_MODE_NOAUDIT)
286 return ns_capable_noaudit(ns, CAP_SYS_PTRACE);
287 return ns_capable(ns, CAP_SYS_PTRACE);
290 /* Returns 0 on success, -errno on denial. */
291 static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
293 const struct cred *cred = current_cred(), *tcred;
294 struct mm_struct *mm;
298 if (!(mode & PTRACE_MODE_FSCREDS) == !(mode & PTRACE_MODE_REALCREDS)) {
299 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
303 /* May we inspect the given task?
304 * This check is used both for attaching with ptrace
305 * and for allowing access to sensitive information in /proc.
307 * ptrace_attach denies several cases that /proc allows
308 * because setting up the necessary parent/child relationship
309 * or halting the specified task is impossible.
312 /* Don't let security modules deny introspection */
313 if (same_thread_group(task, current))
316 if (mode & PTRACE_MODE_FSCREDS) {
317 caller_uid = cred->fsuid;
318 caller_gid = cred->fsgid;
321 * Using the euid would make more sense here, but something
322 * in userland might rely on the old behavior, and this
323 * shouldn't be a security problem since
324 * PTRACE_MODE_REALCREDS implies that the caller explicitly
325 * used a syscall that requests access to another process
326 * (and not a filesystem syscall to procfs).
328 caller_uid = cred->uid;
329 caller_gid = cred->gid;
331 tcred = __task_cred(task);
332 if (uid_eq(caller_uid, tcred->euid) &&
333 uid_eq(caller_uid, tcred->suid) &&
334 uid_eq(caller_uid, tcred->uid) &&
335 gid_eq(caller_gid, tcred->egid) &&
336 gid_eq(caller_gid, tcred->sgid) &&
337 gid_eq(caller_gid, tcred->gid))
339 if (ptrace_has_cap(tcred->user_ns, mode))
346 * If a task drops privileges and becomes nondumpable (through a syscall
347 * like setresuid()) while we are trying to access it, we must ensure
348 * that the dumpability is read after the credentials; otherwise,
349 * we may be able to attach to a task that we shouldn't be able to
350 * attach to (as if the task had dropped privileges without becoming
352 * Pairs with a write barrier in commit_creds().
357 ((get_dumpable(mm) != SUID_DUMP_USER) &&
358 !ptrace_has_cap(mm->user_ns, mode)))
361 return security_ptrace_access_check(task, mode);
364 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
368 err = __ptrace_may_access(task, mode);
373 static int check_ptrace_options(unsigned long data)
375 if (data & ~(unsigned long)PTRACE_O_MASK)
378 if (unlikely(data & PTRACE_O_SUSPEND_SECCOMP)) {
379 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE) ||
380 !IS_ENABLED(CONFIG_SECCOMP))
383 if (!capable(CAP_SYS_ADMIN))
386 if (seccomp_mode(¤t->seccomp) != SECCOMP_MODE_DISABLED ||
387 current->ptrace & PT_SUSPEND_SECCOMP)
393 static int ptrace_attach(struct task_struct *task, long request,
397 bool seize = (request == PTRACE_SEIZE);
405 * This duplicates the check in check_ptrace_options() because
406 * ptrace_attach() and ptrace_setoptions() have historically
407 * used different error codes for unknown ptrace options.
409 if (flags & ~(unsigned long)PTRACE_O_MASK)
411 retval = check_ptrace_options(flags);
414 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
422 if (unlikely(task->flags & PF_KTHREAD))
424 if (same_thread_group(task, current))
428 * Protect exec's credential calculations against our interference;
429 * SUID, SGID and LSM creds get determined differently
432 retval = -ERESTARTNOINTR;
433 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
437 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH_REALCREDS);
442 write_lock_irq(&tasklist_lock);
444 if (unlikely(task->exit_state))
445 goto unlock_tasklist;
447 goto unlock_tasklist;
451 task->ptrace = flags;
453 ptrace_link(task, current);
455 /* SEIZE doesn't trap tracee on attach */
457 send_sig_info(SIGSTOP, SEND_SIG_PRIV, task);
459 spin_lock(&task->sighand->siglock);
462 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
463 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
464 * will be cleared if the child completes the transition or any
465 * event which clears the group stop states happens. We'll wait
466 * for the transition to complete before returning from this
469 * This hides STOPPED -> RUNNING -> TRACED transition from the
470 * attaching thread but a different thread in the same group can
471 * still observe the transient RUNNING state. IOW, if another
472 * thread's WNOHANG wait(2) on the stopped tracee races against
473 * ATTACH, the wait(2) may fail due to the transient RUNNING.
475 * The following task_is_stopped() test is safe as both transitions
476 * in and out of STOPPED are protected by siglock.
478 if (task_is_stopped(task) &&
479 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
480 signal_wake_up_state(task, __TASK_STOPPED);
482 spin_unlock(&task->sighand->siglock);
486 write_unlock_irq(&tasklist_lock);
488 mutex_unlock(&task->signal->cred_guard_mutex);
492 * We do not bother to change retval or clear JOBCTL_TRAPPING
493 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
494 * not return to user-mode, it will exit and clear this bit in
495 * __ptrace_unlink() if it wasn't already cleared by the tracee;
496 * and until then nobody can ptrace this task.
498 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT, TASK_KILLABLE);
499 proc_ptrace_connector(task, PTRACE_ATTACH);
506 * ptrace_traceme -- helper for PTRACE_TRACEME
508 * Performs checks and sets PT_PTRACED.
509 * Should be used by all ptrace implementations for PTRACE_TRACEME.
511 static int ptrace_traceme(void)
515 write_lock_irq(&tasklist_lock);
516 /* Are we already being traced? */
517 if (!current->ptrace) {
518 ret = security_ptrace_traceme(current->parent);
520 * Check PF_EXITING to ensure ->real_parent has not passed
521 * exit_ptrace(). Otherwise we don't report the error but
522 * pretend ->real_parent untraces us right after return.
524 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
525 current->ptrace = PT_PTRACED;
526 ptrace_link(current, current->real_parent);
529 write_unlock_irq(&tasklist_lock);
535 * Called with irqs disabled, returns true if childs should reap themselves.
537 static int ignoring_children(struct sighand_struct *sigh)
540 spin_lock(&sigh->siglock);
541 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
542 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
543 spin_unlock(&sigh->siglock);
548 * Called with tasklist_lock held for writing.
549 * Unlink a traced task, and clean it up if it was a traced zombie.
550 * Return true if it needs to be reaped with release_task().
551 * (We can't call release_task() here because we already hold tasklist_lock.)
553 * If it's a zombie, our attachedness prevented normal parent notification
554 * or self-reaping. Do notification now if it would have happened earlier.
555 * If it should reap itself, return true.
557 * If it's our own child, there is no notification to do. But if our normal
558 * children self-reap, then this child was prevented by ptrace and we must
559 * reap it now, in that case we must also wake up sub-threads sleeping in
562 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
568 if (p->exit_state != EXIT_ZOMBIE)
571 dead = !thread_group_leader(p);
573 if (!dead && thread_group_empty(p)) {
574 if (!same_thread_group(p->real_parent, tracer))
575 dead = do_notify_parent(p, p->exit_signal);
576 else if (ignoring_children(tracer->sighand)) {
577 __wake_up_parent(p, tracer);
581 /* Mark it as in the process of being reaped. */
583 p->exit_state = EXIT_DEAD;
587 static int ptrace_detach(struct task_struct *child, unsigned int data)
589 if (!valid_signal(data))
592 /* Architecture-specific hardware disable .. */
593 ptrace_disable(child);
595 write_lock_irq(&tasklist_lock);
597 * We rely on ptrace_freeze_traced(). It can't be killed and
598 * untraced by another thread, it can't be a zombie.
600 WARN_ON(!child->ptrace || child->exit_state);
602 * tasklist_lock avoids the race with wait_task_stopped(), see
603 * the comment in ptrace_resume().
605 child->exit_code = data;
606 __ptrace_detach(current, child);
607 write_unlock_irq(&tasklist_lock);
609 proc_ptrace_connector(child, PTRACE_DETACH);
615 * Detach all tasks we were using ptrace on. Called with tasklist held
618 void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
620 struct task_struct *p, *n;
622 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
623 if (unlikely(p->ptrace & PT_EXITKILL))
624 send_sig_info(SIGKILL, SEND_SIG_PRIV, p);
626 if (__ptrace_detach(tracer, p))
627 list_add(&p->ptrace_entry, dead);
631 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
637 int this_len, retval;
639 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
640 retval = ptrace_access_vm(tsk, src, buf, this_len, FOLL_FORCE);
647 if (copy_to_user(dst, buf, retval))
657 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
663 int this_len, retval;
665 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
666 if (copy_from_user(buf, src, this_len))
668 retval = ptrace_access_vm(tsk, dst, buf, this_len,
669 FOLL_FORCE | FOLL_WRITE);
683 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
688 ret = check_ptrace_options(data);
692 /* Avoid intermediate state when all opts are cleared */
693 flags = child->ptrace;
694 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
695 flags |= (data << PT_OPT_FLAG_SHIFT);
696 child->ptrace = flags;
701 static int ptrace_getsiginfo(struct task_struct *child, kernel_siginfo_t *info)
706 if (lock_task_sighand(child, &flags)) {
708 if (likely(child->last_siginfo != NULL)) {
709 copy_siginfo(info, child->last_siginfo);
712 unlock_task_sighand(child, &flags);
717 static int ptrace_setsiginfo(struct task_struct *child, const kernel_siginfo_t *info)
722 if (lock_task_sighand(child, &flags)) {
724 if (likely(child->last_siginfo != NULL)) {
725 copy_siginfo(child->last_siginfo, info);
728 unlock_task_sighand(child, &flags);
733 static int ptrace_peek_siginfo(struct task_struct *child,
737 struct ptrace_peeksiginfo_args arg;
738 struct sigpending *pending;
742 ret = copy_from_user(&arg, (void __user *) addr,
743 sizeof(struct ptrace_peeksiginfo_args));
747 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
748 return -EINVAL; /* unknown flags */
753 /* Ensure arg.off fits in an unsigned long */
754 if (arg.off > ULONG_MAX)
757 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
758 pending = &child->signal->shared_pending;
760 pending = &child->pending;
762 for (i = 0; i < arg.nr; ) {
763 kernel_siginfo_t info;
764 unsigned long off = arg.off + i;
767 spin_lock_irq(&child->sighand->siglock);
768 list_for_each_entry(q, &pending->list, list) {
771 copy_siginfo(&info, &q->info);
775 spin_unlock_irq(&child->sighand->siglock);
777 if (!found) /* beyond the end of the list */
781 if (unlikely(in_compat_syscall())) {
782 compat_siginfo_t __user *uinfo = compat_ptr(data);
784 if (copy_siginfo_to_user32(uinfo, &info)) {
792 siginfo_t __user *uinfo = (siginfo_t __user *) data;
794 if (copy_siginfo_to_user(uinfo, &info)) {
800 data += sizeof(siginfo_t);
803 if (signal_pending(current))
815 #ifdef PTRACE_SINGLESTEP
816 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
818 #define is_singlestep(request) 0
821 #ifdef PTRACE_SINGLEBLOCK
822 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
824 #define is_singleblock(request) 0
828 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
830 #define is_sysemu_singlestep(request) 0
833 static int ptrace_resume(struct task_struct *child, long request,
838 if (!valid_signal(data))
841 if (request == PTRACE_SYSCALL)
842 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
844 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
846 #ifdef TIF_SYSCALL_EMU
847 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
848 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
850 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
853 if (is_singleblock(request)) {
854 if (unlikely(!arch_has_block_step()))
856 user_enable_block_step(child);
857 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
858 if (unlikely(!arch_has_single_step()))
860 user_enable_single_step(child);
862 user_disable_single_step(child);
866 * Change ->exit_code and ->state under siglock to avoid the race
867 * with wait_task_stopped() in between; a non-zero ->exit_code will
868 * wrongly look like another report from tracee.
870 * Note that we need siglock even if ->exit_code == data and/or this
871 * status was not reported yet, the new status must not be cleared by
872 * wait_task_stopped() after resume.
874 * If data == 0 we do not care if wait_task_stopped() reports the old
875 * status and clears the code too; this can't race with the tracee, it
876 * takes siglock after resume.
878 need_siglock = data && !thread_group_empty(current);
880 spin_lock_irq(&child->sighand->siglock);
881 child->exit_code = data;
882 wake_up_state(child, __TASK_TRACED);
884 spin_unlock_irq(&child->sighand->siglock);
889 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
891 static const struct user_regset *
892 find_regset(const struct user_regset_view *view, unsigned int type)
894 const struct user_regset *regset;
897 for (n = 0; n < view->n; ++n) {
898 regset = view->regsets + n;
899 if (regset->core_note_type == type)
906 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
909 const struct user_regset_view *view = task_user_regset_view(task);
910 const struct user_regset *regset = find_regset(view, type);
913 if (!regset || (kiov->iov_len % regset->size) != 0)
916 regset_no = regset - view->regsets;
917 kiov->iov_len = min(kiov->iov_len,
918 (__kernel_size_t) (regset->n * regset->size));
920 if (req == PTRACE_GETREGSET)
921 return copy_regset_to_user(task, view, regset_no, 0,
922 kiov->iov_len, kiov->iov_base);
924 return copy_regset_from_user(task, view, regset_no, 0,
925 kiov->iov_len, kiov->iov_base);
929 * This is declared in linux/regset.h and defined in machine-dependent
930 * code. We put the export here, near the primary machine-neutral use,
931 * to ensure no machine forgets it.
933 EXPORT_SYMBOL_GPL(task_user_regset_view);
936 ptrace_get_syscall_info_entry(struct task_struct *child, struct pt_regs *regs,
937 struct ptrace_syscall_info *info)
939 unsigned long args[ARRAY_SIZE(info->entry.args)];
942 info->op = PTRACE_SYSCALL_INFO_ENTRY;
943 info->entry.nr = syscall_get_nr(child, regs);
944 syscall_get_arguments(child, regs, args);
945 for (i = 0; i < ARRAY_SIZE(args); i++)
946 info->entry.args[i] = args[i];
948 /* args is the last field in struct ptrace_syscall_info.entry */
949 return offsetofend(struct ptrace_syscall_info, entry.args);
953 ptrace_get_syscall_info_seccomp(struct task_struct *child, struct pt_regs *regs,
954 struct ptrace_syscall_info *info)
957 * As struct ptrace_syscall_info.entry is currently a subset
958 * of struct ptrace_syscall_info.seccomp, it makes sense to
959 * initialize that subset using ptrace_get_syscall_info_entry().
960 * This can be reconsidered in the future if these structures
961 * diverge significantly enough.
963 ptrace_get_syscall_info_entry(child, regs, info);
964 info->op = PTRACE_SYSCALL_INFO_SECCOMP;
965 info->seccomp.ret_data = child->ptrace_message;
967 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
968 return offsetofend(struct ptrace_syscall_info, seccomp.ret_data);
972 ptrace_get_syscall_info_exit(struct task_struct *child, struct pt_regs *regs,
973 struct ptrace_syscall_info *info)
975 info->op = PTRACE_SYSCALL_INFO_EXIT;
976 info->exit.rval = syscall_get_error(child, regs);
977 info->exit.is_error = !!info->exit.rval;
978 if (!info->exit.is_error)
979 info->exit.rval = syscall_get_return_value(child, regs);
981 /* is_error is the last field in struct ptrace_syscall_info.exit */
982 return offsetofend(struct ptrace_syscall_info, exit.is_error);
986 ptrace_get_syscall_info(struct task_struct *child, unsigned long user_size,
989 struct pt_regs *regs = task_pt_regs(child);
990 struct ptrace_syscall_info info = {
991 .op = PTRACE_SYSCALL_INFO_NONE,
992 .arch = syscall_get_arch(child),
993 .instruction_pointer = instruction_pointer(regs),
994 .stack_pointer = user_stack_pointer(regs),
996 unsigned long actual_size = offsetof(struct ptrace_syscall_info, entry);
997 unsigned long write_size;
1000 * This does not need lock_task_sighand() to access
1001 * child->last_siginfo because ptrace_freeze_traced()
1002 * called earlier by ptrace_check_attach() ensures that
1003 * the tracee cannot go away and clear its last_siginfo.
1005 switch (child->last_siginfo ? child->last_siginfo->si_code : 0) {
1006 case SIGTRAP | 0x80:
1007 switch (child->ptrace_message) {
1008 case PTRACE_EVENTMSG_SYSCALL_ENTRY:
1009 actual_size = ptrace_get_syscall_info_entry(child, regs,
1012 case PTRACE_EVENTMSG_SYSCALL_EXIT:
1013 actual_size = ptrace_get_syscall_info_exit(child, regs,
1018 case SIGTRAP | (PTRACE_EVENT_SECCOMP << 8):
1019 actual_size = ptrace_get_syscall_info_seccomp(child, regs,
1024 write_size = min(actual_size, user_size);
1025 return copy_to_user(datavp, &info, write_size) ? -EFAULT : actual_size;
1027 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
1029 int ptrace_request(struct task_struct *child, long request,
1030 unsigned long addr, unsigned long data)
1032 bool seized = child->ptrace & PT_SEIZED;
1034 kernel_siginfo_t siginfo, *si;
1035 void __user *datavp = (void __user *) data;
1036 unsigned long __user *datalp = datavp;
1037 unsigned long flags;
1040 case PTRACE_PEEKTEXT:
1041 case PTRACE_PEEKDATA:
1042 return generic_ptrace_peekdata(child, addr, data);
1043 case PTRACE_POKETEXT:
1044 case PTRACE_POKEDATA:
1045 return generic_ptrace_pokedata(child, addr, data);
1047 #ifdef PTRACE_OLDSETOPTIONS
1048 case PTRACE_OLDSETOPTIONS:
1050 case PTRACE_SETOPTIONS:
1051 ret = ptrace_setoptions(child, data);
1053 case PTRACE_GETEVENTMSG:
1054 ret = put_user(child->ptrace_message, datalp);
1057 case PTRACE_PEEKSIGINFO:
1058 ret = ptrace_peek_siginfo(child, addr, data);
1061 case PTRACE_GETSIGINFO:
1062 ret = ptrace_getsiginfo(child, &siginfo);
1064 ret = copy_siginfo_to_user(datavp, &siginfo);
1067 case PTRACE_SETSIGINFO:
1068 ret = copy_siginfo_from_user(&siginfo, datavp);
1070 ret = ptrace_setsiginfo(child, &siginfo);
1073 case PTRACE_GETSIGMASK: {
1076 if (addr != sizeof(sigset_t)) {
1081 if (test_tsk_restore_sigmask(child))
1082 mask = &child->saved_sigmask;
1084 mask = &child->blocked;
1086 if (copy_to_user(datavp, mask, sizeof(sigset_t)))
1094 case PTRACE_SETSIGMASK: {
1097 if (addr != sizeof(sigset_t)) {
1102 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
1107 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
1110 * Every thread does recalc_sigpending() after resume, so
1111 * retarget_shared_pending() and recalc_sigpending() are not
1114 spin_lock_irq(&child->sighand->siglock);
1115 child->blocked = new_set;
1116 spin_unlock_irq(&child->sighand->siglock);
1118 clear_tsk_restore_sigmask(child);
1124 case PTRACE_INTERRUPT:
1126 * Stop tracee without any side-effect on signal or job
1127 * control. At least one trap is guaranteed to happen
1128 * after this request. If @child is already trapped, the
1129 * current trap is not disturbed and another trap will
1130 * happen after the current trap is ended with PTRACE_CONT.
1132 * The actual trap might not be PTRACE_EVENT_STOP trap but
1133 * the pending condition is cleared regardless.
1135 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1139 * INTERRUPT doesn't disturb existing trap sans one
1140 * exception. If ptracer issued LISTEN for the current
1141 * STOP, this INTERRUPT should clear LISTEN and re-trap
1144 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
1145 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
1147 unlock_task_sighand(child, &flags);
1153 * Listen for events. Tracee must be in STOP. It's not
1154 * resumed per-se but is not considered to be in TRACED by
1155 * wait(2) or ptrace(2). If an async event (e.g. group
1156 * stop state change) happens, tracee will enter STOP trap
1157 * again. Alternatively, ptracer can issue INTERRUPT to
1158 * finish listening and re-trap tracee into STOP.
1160 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
1163 si = child->last_siginfo;
1164 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
1165 child->jobctl |= JOBCTL_LISTENING;
1167 * If NOTIFY is set, it means event happened between
1168 * start of this trap and now. Trigger re-trap.
1170 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
1171 ptrace_signal_wake_up(child, true);
1174 unlock_task_sighand(child, &flags);
1177 case PTRACE_DETACH: /* detach a process that was attached. */
1178 ret = ptrace_detach(child, data);
1181 #ifdef CONFIG_BINFMT_ELF_FDPIC
1182 case PTRACE_GETFDPIC: {
1183 struct mm_struct *mm = get_task_mm(child);
1184 unsigned long tmp = 0;
1191 case PTRACE_GETFDPIC_EXEC:
1192 tmp = mm->context.exec_fdpic_loadmap;
1194 case PTRACE_GETFDPIC_INTERP:
1195 tmp = mm->context.interp_fdpic_loadmap;
1202 ret = put_user(tmp, datalp);
1207 #ifdef PTRACE_SINGLESTEP
1208 case PTRACE_SINGLESTEP:
1210 #ifdef PTRACE_SINGLEBLOCK
1211 case PTRACE_SINGLEBLOCK:
1213 #ifdef PTRACE_SYSEMU
1215 case PTRACE_SYSEMU_SINGLESTEP:
1217 case PTRACE_SYSCALL:
1219 return ptrace_resume(child, request, data);
1222 send_sig_info(SIGKILL, SEND_SIG_NOINFO, child);
1225 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1226 case PTRACE_GETREGSET:
1227 case PTRACE_SETREGSET: {
1229 struct iovec __user *uiov = datavp;
1231 if (!access_ok(uiov, sizeof(*uiov)))
1234 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
1235 __get_user(kiov.iov_len, &uiov->iov_len))
1238 ret = ptrace_regset(child, request, addr, &kiov);
1240 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1244 case PTRACE_GET_SYSCALL_INFO:
1245 ret = ptrace_get_syscall_info(child, addr, datavp);
1249 case PTRACE_SECCOMP_GET_FILTER:
1250 ret = seccomp_get_filter(child, addr, datavp);
1253 case PTRACE_SECCOMP_GET_METADATA:
1254 ret = seccomp_get_metadata(child, addr, datavp);
1264 #ifndef arch_ptrace_attach
1265 #define arch_ptrace_attach(child) do { } while (0)
1268 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1269 unsigned long, data)
1271 struct task_struct *child;
1274 if (request == PTRACE_TRACEME) {
1275 ret = ptrace_traceme();
1277 arch_ptrace_attach(current);
1281 child = find_get_task_by_vpid(pid);
1287 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1288 ret = ptrace_attach(child, request, addr, data);
1290 * Some architectures need to do book-keeping after
1294 arch_ptrace_attach(child);
1295 goto out_put_task_struct;
1298 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1299 request == PTRACE_INTERRUPT);
1301 goto out_put_task_struct;
1303 ret = arch_ptrace(child, request, addr, data);
1304 if (ret || request != PTRACE_DETACH)
1305 ptrace_unfreeze_traced(child);
1307 out_put_task_struct:
1308 put_task_struct(child);
1313 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1319 copied = ptrace_access_vm(tsk, addr, &tmp, sizeof(tmp), FOLL_FORCE);
1320 if (copied != sizeof(tmp))
1322 return put_user(tmp, (unsigned long __user *)data);
1325 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1330 copied = ptrace_access_vm(tsk, addr, &data, sizeof(data),
1331 FOLL_FORCE | FOLL_WRITE);
1332 return (copied == sizeof(data)) ? 0 : -EIO;
1335 #if defined CONFIG_COMPAT
1337 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1338 compat_ulong_t addr, compat_ulong_t data)
1340 compat_ulong_t __user *datap = compat_ptr(data);
1341 compat_ulong_t word;
1342 kernel_siginfo_t siginfo;
1346 case PTRACE_PEEKTEXT:
1347 case PTRACE_PEEKDATA:
1348 ret = ptrace_access_vm(child, addr, &word, sizeof(word),
1350 if (ret != sizeof(word))
1353 ret = put_user(word, datap);
1356 case PTRACE_POKETEXT:
1357 case PTRACE_POKEDATA:
1358 ret = ptrace_access_vm(child, addr, &data, sizeof(data),
1359 FOLL_FORCE | FOLL_WRITE);
1360 ret = (ret != sizeof(data) ? -EIO : 0);
1363 case PTRACE_GETEVENTMSG:
1364 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1367 case PTRACE_GETSIGINFO:
1368 ret = ptrace_getsiginfo(child, &siginfo);
1370 ret = copy_siginfo_to_user32(
1371 (struct compat_siginfo __user *) datap,
1375 case PTRACE_SETSIGINFO:
1376 ret = copy_siginfo_from_user32(
1377 &siginfo, (struct compat_siginfo __user *) datap);
1379 ret = ptrace_setsiginfo(child, &siginfo);
1381 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1382 case PTRACE_GETREGSET:
1383 case PTRACE_SETREGSET:
1386 struct compat_iovec __user *uiov =
1387 (struct compat_iovec __user *) datap;
1391 if (!access_ok(uiov, sizeof(*uiov)))
1394 if (__get_user(ptr, &uiov->iov_base) ||
1395 __get_user(len, &uiov->iov_len))
1398 kiov.iov_base = compat_ptr(ptr);
1401 ret = ptrace_regset(child, request, addr, &kiov);
1403 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1409 ret = ptrace_request(child, request, addr, data);
1415 COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1416 compat_long_t, addr, compat_long_t, data)
1418 struct task_struct *child;
1421 if (request == PTRACE_TRACEME) {
1422 ret = ptrace_traceme();
1426 child = find_get_task_by_vpid(pid);
1432 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
1433 ret = ptrace_attach(child, request, addr, data);
1435 * Some architectures need to do book-keeping after
1439 arch_ptrace_attach(child);
1440 goto out_put_task_struct;
1443 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1444 request == PTRACE_INTERRUPT);
1446 ret = compat_arch_ptrace(child, request, addr, data);
1447 if (ret || request != PTRACE_DETACH)
1448 ptrace_unfreeze_traced(child);
1451 out_put_task_struct:
1452 put_task_struct(child);
1456 #endif /* CONFIG_COMPAT */