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>
34 #include <linux/minmax.h>
36 #include <asm/syscall.h> /* for syscall_get_* */
39 * Access another process' address space via ptrace.
40 * Source/target buffer must be kernel space,
41 * Do not walk the page table directly, use get_user_pages
43 int ptrace_access_vm(struct task_struct
*tsk
, unsigned long addr
,
44 void *buf
, int len
, unsigned int gup_flags
)
49 mm
= get_task_mm(tsk
);
54 (current
!= tsk
->parent
) ||
55 ((get_dumpable(mm
) != SUID_DUMP_USER
) &&
56 !ptracer_capable(tsk
, mm
->user_ns
))) {
61 ret
= __access_remote_vm(mm
, addr
, buf
, len
, gup_flags
);
68 void __ptrace_link(struct task_struct
*child
, struct task_struct
*new_parent
,
69 const struct cred
*ptracer_cred
)
71 BUG_ON(!list_empty(&child
->ptrace_entry
));
72 list_add(&child
->ptrace_entry
, &new_parent
->ptraced
);
73 child
->parent
= new_parent
;
74 child
->ptracer_cred
= get_cred(ptracer_cred
);
78 * ptrace a task: make the debugger its new parent and
79 * move it to the ptrace list.
81 * Must be called with the tasklist lock write-held.
83 static void ptrace_link(struct task_struct
*child
, struct task_struct
*new_parent
)
85 __ptrace_link(child
, new_parent
, current_cred());
89 * __ptrace_unlink - unlink ptracee and restore its execution state
90 * @child: ptracee to be unlinked
92 * Remove @child from the ptrace list, move it back to the original parent,
93 * and restore the execution state so that it conforms to the group stop
96 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
97 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
98 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
99 * If the ptracer is exiting, the ptracee can be in any state.
101 * After detach, the ptracee should be in a state which conforms to the
102 * group stop. If the group is stopped or in the process of stopping, the
103 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
104 * up from TASK_TRACED.
106 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
107 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
108 * to but in the opposite direction of what happens while attaching to a
109 * stopped task. However, in this direction, the intermediate RUNNING
110 * state is not hidden even from the current ptracer and if it immediately
111 * re-attaches and performs a WNOHANG wait(2), it may fail.
114 * write_lock_irq(tasklist_lock)
116 void __ptrace_unlink(struct task_struct
*child
)
118 const struct cred
*old_cred
;
119 BUG_ON(!child
->ptrace
);
121 clear_task_syscall_work(child
, SYSCALL_TRACE
);
122 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
123 clear_task_syscall_work(child
, SYSCALL_EMU
);
126 child
->parent
= child
->real_parent
;
127 list_del_init(&child
->ptrace_entry
);
128 old_cred
= child
->ptracer_cred
;
129 child
->ptracer_cred
= NULL
;
132 spin_lock(&child
->sighand
->siglock
);
135 * Clear all pending traps and TRAPPING. TRAPPING should be
136 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
138 task_clear_jobctl_pending(child
, JOBCTL_TRAP_MASK
);
139 task_clear_jobctl_trapping(child
);
142 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
145 if (!(child
->flags
& PF_EXITING
) &&
146 (child
->signal
->flags
& SIGNAL_STOP_STOPPED
||
147 child
->signal
->group_stop_count
)) {
148 child
->jobctl
|= JOBCTL_STOP_PENDING
;
151 * This is only possible if this thread was cloned by the
152 * traced task running in the stopped group, set the signal
153 * for the future reports.
154 * FIXME: we should change ptrace_init_task() to handle this
157 if (!(child
->jobctl
& JOBCTL_STOP_SIGMASK
))
158 child
->jobctl
|= SIGSTOP
;
162 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
163 * @child in the butt. Note that @resume should be used iff @child
164 * is in TASK_TRACED; otherwise, we might unduly disrupt
165 * TASK_KILLABLE sleeps.
167 if (child
->jobctl
& JOBCTL_STOP_PENDING
|| task_is_traced(child
))
168 ptrace_signal_wake_up(child
, true);
170 spin_unlock(&child
->sighand
->siglock
);
173 static bool looks_like_a_spurious_pid(struct task_struct
*task
)
175 if (task
->exit_code
!= ((PTRACE_EVENT_EXEC
<< 8) | SIGTRAP
))
178 if (task_pid_vnr(task
) == task
->ptrace_message
)
181 * The tracee changed its pid but the PTRACE_EVENT_EXEC event
182 * was not wait()'ed, most probably debugger targets the old
183 * leader which was destroyed in de_thread().
189 * Ensure that nothing can wake it up, even SIGKILL
191 * A task is switched to this state while a ptrace operation is in progress;
192 * such that the ptrace operation is uninterruptible.
194 static bool ptrace_freeze_traced(struct task_struct
*task
)
198 /* Lockless, nobody but us can set this flag */
199 if (task
->jobctl
& JOBCTL_LISTENING
)
202 spin_lock_irq(&task
->sighand
->siglock
);
203 if (task_is_traced(task
) && !looks_like_a_spurious_pid(task
) &&
204 !__fatal_signal_pending(task
)) {
205 task
->jobctl
|= JOBCTL_PTRACE_FROZEN
;
208 spin_unlock_irq(&task
->sighand
->siglock
);
213 static void ptrace_unfreeze_traced(struct task_struct
*task
)
218 * The child may be awake and may have cleared
219 * JOBCTL_PTRACE_FROZEN (see ptrace_resume). The child will
220 * not set JOBCTL_PTRACE_FROZEN or enter __TASK_TRACED anew.
222 if (lock_task_sighand(task
, &flags
)) {
223 task
->jobctl
&= ~JOBCTL_PTRACE_FROZEN
;
224 if (__fatal_signal_pending(task
)) {
225 task
->jobctl
&= ~TASK_TRACED
;
226 wake_up_state(task
, __TASK_TRACED
);
228 unlock_task_sighand(task
, &flags
);
233 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
234 * @child: ptracee to check for
235 * @ignore_state: don't check whether @child is currently %TASK_TRACED
237 * Check whether @child is being ptraced by %current and ready for further
238 * ptrace operations. If @ignore_state is %false, @child also should be in
239 * %TASK_TRACED state and on return the child is guaranteed to be traced
240 * and not executing. If @ignore_state is %true, @child can be in any
244 * Grabs and releases tasklist_lock and @child->sighand->siglock.
247 * 0 on success, -ESRCH if %child is not ready.
249 static int ptrace_check_attach(struct task_struct
*child
, bool ignore_state
)
254 * We take the read lock around doing both checks to close a
255 * possible race where someone else was tracing our child and
256 * detached between these two checks. After this locked check,
257 * we are sure that this is our traced child and that can only
258 * be changed by us so it's not changing right after this.
260 read_lock(&tasklist_lock
);
261 if (child
->ptrace
&& child
->parent
== current
) {
263 * child->sighand can't be NULL, release_task()
264 * does ptrace_unlink() before __exit_signal().
266 if (ignore_state
|| ptrace_freeze_traced(child
))
269 read_unlock(&tasklist_lock
);
271 if (!ret
&& !ignore_state
&&
272 WARN_ON_ONCE(!wait_task_inactive(child
, __TASK_TRACED
)))
278 static bool ptrace_has_cap(struct user_namespace
*ns
, unsigned int mode
)
280 if (mode
& PTRACE_MODE_NOAUDIT
)
281 return ns_capable_noaudit(ns
, CAP_SYS_PTRACE
);
282 return ns_capable(ns
, CAP_SYS_PTRACE
);
285 /* Returns 0 on success, -errno on denial. */
286 static int __ptrace_may_access(struct task_struct
*task
, unsigned int mode
)
288 const struct cred
*cred
= current_cred(), *tcred
;
289 struct mm_struct
*mm
;
293 if (!(mode
& PTRACE_MODE_FSCREDS
) == !(mode
& PTRACE_MODE_REALCREDS
)) {
294 WARN(1, "denying ptrace access check without PTRACE_MODE_*CREDS\n");
298 /* May we inspect the given task?
299 * This check is used both for attaching with ptrace
300 * and for allowing access to sensitive information in /proc.
302 * ptrace_attach denies several cases that /proc allows
303 * because setting up the necessary parent/child relationship
304 * or halting the specified task is impossible.
307 /* Don't let security modules deny introspection */
308 if (same_thread_group(task
, current
))
311 if (mode
& PTRACE_MODE_FSCREDS
) {
312 caller_uid
= cred
->fsuid
;
313 caller_gid
= cred
->fsgid
;
316 * Using the euid would make more sense here, but something
317 * in userland might rely on the old behavior, and this
318 * shouldn't be a security problem since
319 * PTRACE_MODE_REALCREDS implies that the caller explicitly
320 * used a syscall that requests access to another process
321 * (and not a filesystem syscall to procfs).
323 caller_uid
= cred
->uid
;
324 caller_gid
= cred
->gid
;
326 tcred
= __task_cred(task
);
327 if (uid_eq(caller_uid
, tcred
->euid
) &&
328 uid_eq(caller_uid
, tcred
->suid
) &&
329 uid_eq(caller_uid
, tcred
->uid
) &&
330 gid_eq(caller_gid
, tcred
->egid
) &&
331 gid_eq(caller_gid
, tcred
->sgid
) &&
332 gid_eq(caller_gid
, tcred
->gid
))
334 if (ptrace_has_cap(tcred
->user_ns
, mode
))
341 * If a task drops privileges and becomes nondumpable (through a syscall
342 * like setresuid()) while we are trying to access it, we must ensure
343 * that the dumpability is read after the credentials; otherwise,
344 * we may be able to attach to a task that we shouldn't be able to
345 * attach to (as if the task had dropped privileges without becoming
347 * Pairs with a write barrier in commit_creds().
352 ((get_dumpable(mm
) != SUID_DUMP_USER
) &&
353 !ptrace_has_cap(mm
->user_ns
, mode
)))
356 return security_ptrace_access_check(task
, mode
);
359 bool ptrace_may_access(struct task_struct
*task
, unsigned int mode
)
363 err
= __ptrace_may_access(task
, mode
);
368 static int check_ptrace_options(unsigned long data
)
370 if (data
& ~(unsigned long)PTRACE_O_MASK
)
373 if (unlikely(data
& PTRACE_O_SUSPEND_SECCOMP
)) {
374 if (!IS_ENABLED(CONFIG_CHECKPOINT_RESTORE
) ||
375 !IS_ENABLED(CONFIG_SECCOMP
))
378 if (!capable(CAP_SYS_ADMIN
))
381 if (seccomp_mode(¤t
->seccomp
) != SECCOMP_MODE_DISABLED
||
382 current
->ptrace
& PT_SUSPEND_SECCOMP
)
388 static int ptrace_attach(struct task_struct
*task
, long request
,
392 bool seize
= (request
== PTRACE_SEIZE
);
400 * This duplicates the check in check_ptrace_options() because
401 * ptrace_attach() and ptrace_setoptions() have historically
402 * used different error codes for unknown ptrace options.
404 if (flags
& ~(unsigned long)PTRACE_O_MASK
)
406 retval
= check_ptrace_options(flags
);
409 flags
= PT_PTRACED
| PT_SEIZED
| (flags
<< PT_OPT_FLAG_SHIFT
);
417 if (unlikely(task
->flags
& PF_KTHREAD
))
419 if (same_thread_group(task
, current
))
423 * Protect exec's credential calculations against our interference;
424 * SUID, SGID and LSM creds get determined differently
427 retval
= -ERESTARTNOINTR
;
428 if (mutex_lock_interruptible(&task
->signal
->cred_guard_mutex
))
432 retval
= __ptrace_may_access(task
, PTRACE_MODE_ATTACH_REALCREDS
);
437 write_lock_irq(&tasklist_lock
);
439 if (unlikely(task
->exit_state
))
440 goto unlock_tasklist
;
442 goto unlock_tasklist
;
444 task
->ptrace
= flags
;
446 ptrace_link(task
, current
);
448 /* SEIZE doesn't trap tracee on attach */
450 send_sig_info(SIGSTOP
, SEND_SIG_PRIV
, task
);
452 spin_lock(&task
->sighand
->siglock
);
455 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
456 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
457 * will be cleared if the child completes the transition or any
458 * event which clears the group stop states happens. We'll wait
459 * for the transition to complete before returning from this
462 * This hides STOPPED -> RUNNING -> TRACED transition from the
463 * attaching thread but a different thread in the same group can
464 * still observe the transient RUNNING state. IOW, if another
465 * thread's WNOHANG wait(2) on the stopped tracee races against
466 * ATTACH, the wait(2) may fail due to the transient RUNNING.
468 * The following task_is_stopped() test is safe as both transitions
469 * in and out of STOPPED are protected by siglock.
471 if (task_is_stopped(task
) &&
472 task_set_jobctl_pending(task
, JOBCTL_TRAP_STOP
| JOBCTL_TRAPPING
)) {
473 task
->jobctl
&= ~JOBCTL_STOPPED
;
474 signal_wake_up_state(task
, __TASK_STOPPED
);
477 spin_unlock(&task
->sighand
->siglock
);
481 write_unlock_irq(&tasklist_lock
);
483 mutex_unlock(&task
->signal
->cred_guard_mutex
);
487 * We do not bother to change retval or clear JOBCTL_TRAPPING
488 * if wait_on_bit() was interrupted by SIGKILL. The tracer will
489 * not return to user-mode, it will exit and clear this bit in
490 * __ptrace_unlink() if it wasn't already cleared by the tracee;
491 * and until then nobody can ptrace this task.
493 wait_on_bit(&task
->jobctl
, JOBCTL_TRAPPING_BIT
, TASK_KILLABLE
);
494 proc_ptrace_connector(task
, PTRACE_ATTACH
);
501 * ptrace_traceme -- helper for PTRACE_TRACEME
503 * Performs checks and sets PT_PTRACED.
504 * Should be used by all ptrace implementations for PTRACE_TRACEME.
506 static int ptrace_traceme(void)
510 write_lock_irq(&tasklist_lock
);
511 /* Are we already being traced? */
512 if (!current
->ptrace
) {
513 ret
= security_ptrace_traceme(current
->parent
);
515 * Check PF_EXITING to ensure ->real_parent has not passed
516 * exit_ptrace(). Otherwise we don't report the error but
517 * pretend ->real_parent untraces us right after return.
519 if (!ret
&& !(current
->real_parent
->flags
& PF_EXITING
)) {
520 current
->ptrace
= PT_PTRACED
;
521 ptrace_link(current
, current
->real_parent
);
524 write_unlock_irq(&tasklist_lock
);
530 * Called with irqs disabled, returns true if childs should reap themselves.
532 static int ignoring_children(struct sighand_struct
*sigh
)
535 spin_lock(&sigh
->siglock
);
536 ret
= (sigh
->action
[SIGCHLD
-1].sa
.sa_handler
== SIG_IGN
) ||
537 (sigh
->action
[SIGCHLD
-1].sa
.sa_flags
& SA_NOCLDWAIT
);
538 spin_unlock(&sigh
->siglock
);
543 * Called with tasklist_lock held for writing.
544 * Unlink a traced task, and clean it up if it was a traced zombie.
545 * Return true if it needs to be reaped with release_task().
546 * (We can't call release_task() here because we already hold tasklist_lock.)
548 * If it's a zombie, our attachedness prevented normal parent notification
549 * or self-reaping. Do notification now if it would have happened earlier.
550 * If it should reap itself, return true.
552 * If it's our own child, there is no notification to do. But if our normal
553 * children self-reap, then this child was prevented by ptrace and we must
554 * reap it now, in that case we must also wake up sub-threads sleeping in
557 static bool __ptrace_detach(struct task_struct
*tracer
, struct task_struct
*p
)
563 if (p
->exit_state
!= EXIT_ZOMBIE
)
566 dead
= !thread_group_leader(p
);
568 if (!dead
&& thread_group_empty(p
)) {
569 if (!same_thread_group(p
->real_parent
, tracer
))
570 dead
= do_notify_parent(p
, p
->exit_signal
);
571 else if (ignoring_children(tracer
->sighand
)) {
572 __wake_up_parent(p
, tracer
);
576 /* Mark it as in the process of being reaped. */
578 p
->exit_state
= EXIT_DEAD
;
582 static int ptrace_detach(struct task_struct
*child
, unsigned int data
)
584 if (!valid_signal(data
))
587 /* Architecture-specific hardware disable .. */
588 ptrace_disable(child
);
590 write_lock_irq(&tasklist_lock
);
592 * We rely on ptrace_freeze_traced(). It can't be killed and
593 * untraced by another thread, it can't be a zombie.
595 WARN_ON(!child
->ptrace
|| child
->exit_state
);
597 * tasklist_lock avoids the race with wait_task_stopped(), see
598 * the comment in ptrace_resume().
600 child
->exit_code
= data
;
601 __ptrace_detach(current
, child
);
602 write_unlock_irq(&tasklist_lock
);
604 proc_ptrace_connector(child
, PTRACE_DETACH
);
610 * Detach all tasks we were using ptrace on. Called with tasklist held
613 void exit_ptrace(struct task_struct
*tracer
, struct list_head
*dead
)
615 struct task_struct
*p
, *n
;
617 list_for_each_entry_safe(p
, n
, &tracer
->ptraced
, ptrace_entry
) {
618 if (unlikely(p
->ptrace
& PT_EXITKILL
))
619 send_sig_info(SIGKILL
, SEND_SIG_PRIV
, p
);
621 if (__ptrace_detach(tracer
, p
))
622 list_add(&p
->ptrace_entry
, dead
);
626 int ptrace_readdata(struct task_struct
*tsk
, unsigned long src
, char __user
*dst
, int len
)
632 int this_len
, retval
;
634 this_len
= (len
> sizeof(buf
)) ? sizeof(buf
) : len
;
635 retval
= ptrace_access_vm(tsk
, src
, buf
, this_len
, FOLL_FORCE
);
642 if (copy_to_user(dst
, buf
, retval
))
652 int ptrace_writedata(struct task_struct
*tsk
, char __user
*src
, unsigned long dst
, int len
)
658 int this_len
, retval
;
660 this_len
= (len
> sizeof(buf
)) ? sizeof(buf
) : len
;
661 if (copy_from_user(buf
, src
, this_len
))
663 retval
= ptrace_access_vm(tsk
, dst
, buf
, this_len
,
664 FOLL_FORCE
| FOLL_WRITE
);
678 static int ptrace_setoptions(struct task_struct
*child
, unsigned long data
)
683 ret
= check_ptrace_options(data
);
687 /* Avoid intermediate state when all opts are cleared */
688 flags
= child
->ptrace
;
689 flags
&= ~(PTRACE_O_MASK
<< PT_OPT_FLAG_SHIFT
);
690 flags
|= (data
<< PT_OPT_FLAG_SHIFT
);
691 child
->ptrace
= flags
;
696 static int ptrace_getsiginfo(struct task_struct
*child
, kernel_siginfo_t
*info
)
701 if (lock_task_sighand(child
, &flags
)) {
703 if (likely(child
->last_siginfo
!= NULL
)) {
704 copy_siginfo(info
, child
->last_siginfo
);
707 unlock_task_sighand(child
, &flags
);
712 static int ptrace_setsiginfo(struct task_struct
*child
, const kernel_siginfo_t
*info
)
717 if (lock_task_sighand(child
, &flags
)) {
719 if (likely(child
->last_siginfo
!= NULL
)) {
720 copy_siginfo(child
->last_siginfo
, info
);
723 unlock_task_sighand(child
, &flags
);
728 static int ptrace_peek_siginfo(struct task_struct
*child
,
732 struct ptrace_peeksiginfo_args arg
;
733 struct sigpending
*pending
;
737 ret
= copy_from_user(&arg
, (void __user
*) addr
,
738 sizeof(struct ptrace_peeksiginfo_args
));
742 if (arg
.flags
& ~PTRACE_PEEKSIGINFO_SHARED
)
743 return -EINVAL
; /* unknown flags */
748 /* Ensure arg.off fits in an unsigned long */
749 if (arg
.off
> ULONG_MAX
)
752 if (arg
.flags
& PTRACE_PEEKSIGINFO_SHARED
)
753 pending
= &child
->signal
->shared_pending
;
755 pending
= &child
->pending
;
757 for (i
= 0; i
< arg
.nr
; ) {
758 kernel_siginfo_t info
;
759 unsigned long off
= arg
.off
+ i
;
762 spin_lock_irq(&child
->sighand
->siglock
);
763 list_for_each_entry(q
, &pending
->list
, list
) {
766 copy_siginfo(&info
, &q
->info
);
770 spin_unlock_irq(&child
->sighand
->siglock
);
772 if (!found
) /* beyond the end of the list */
776 if (unlikely(in_compat_syscall())) {
777 compat_siginfo_t __user
*uinfo
= compat_ptr(data
);
779 if (copy_siginfo_to_user32(uinfo
, &info
)) {
787 siginfo_t __user
*uinfo
= (siginfo_t __user
*) data
;
789 if (copy_siginfo_to_user(uinfo
, &info
)) {
795 data
+= sizeof(siginfo_t
);
798 if (signal_pending(current
))
811 static long ptrace_get_rseq_configuration(struct task_struct
*task
,
812 unsigned long size
, void __user
*data
)
814 struct ptrace_rseq_configuration conf
= {
815 .rseq_abi_pointer
= (u64
)(uintptr_t)task
->rseq
,
816 .rseq_abi_size
= sizeof(*task
->rseq
),
817 .signature
= task
->rseq_sig
,
821 size
= min_t(unsigned long, size
, sizeof(conf
));
822 if (copy_to_user(data
, &conf
, size
))
828 #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
830 #ifdef PTRACE_SINGLEBLOCK
831 #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
833 #define is_singleblock(request) 0
837 #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
839 #define is_sysemu_singlestep(request) 0
842 static int ptrace_resume(struct task_struct
*child
, long request
,
845 if (!valid_signal(data
))
848 if (request
== PTRACE_SYSCALL
)
849 set_task_syscall_work(child
, SYSCALL_TRACE
);
851 clear_task_syscall_work(child
, SYSCALL_TRACE
);
853 #if defined(CONFIG_GENERIC_ENTRY) || defined(TIF_SYSCALL_EMU)
854 if (request
== PTRACE_SYSEMU
|| request
== PTRACE_SYSEMU_SINGLESTEP
)
855 set_task_syscall_work(child
, SYSCALL_EMU
);
857 clear_task_syscall_work(child
, SYSCALL_EMU
);
860 if (is_singleblock(request
)) {
861 if (unlikely(!arch_has_block_step()))
863 user_enable_block_step(child
);
864 } else if (is_singlestep(request
) || is_sysemu_singlestep(request
)) {
865 if (unlikely(!arch_has_single_step()))
867 user_enable_single_step(child
);
869 user_disable_single_step(child
);
873 * Change ->exit_code and ->state under siglock to avoid the race
874 * with wait_task_stopped() in between; a non-zero ->exit_code will
875 * wrongly look like another report from tracee.
877 * Note that we need siglock even if ->exit_code == data and/or this
878 * status was not reported yet, the new status must not be cleared by
879 * wait_task_stopped() after resume.
881 spin_lock_irq(&child
->sighand
->siglock
);
882 child
->exit_code
= data
;
883 child
->jobctl
&= ~JOBCTL_TRACED
;
884 wake_up_state(child
, __TASK_TRACED
);
885 spin_unlock_irq(&child
->sighand
->siglock
);
890 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
892 static const struct user_regset
*
893 find_regset(const struct user_regset_view
*view
, unsigned int type
)
895 const struct user_regset
*regset
;
898 for (n
= 0; n
< view
->n
; ++n
) {
899 regset
= view
->regsets
+ n
;
900 if (regset
->core_note_type
== type
)
907 static int ptrace_regset(struct task_struct
*task
, int req
, unsigned int type
,
910 const struct user_regset_view
*view
= task_user_regset_view(task
);
911 const struct user_regset
*regset
= find_regset(view
, type
);
914 if (!regset
|| (kiov
->iov_len
% regset
->size
) != 0)
917 regset_no
= regset
- view
->regsets
;
918 kiov
->iov_len
= min(kiov
->iov_len
,
919 (__kernel_size_t
) (regset
->n
* regset
->size
));
921 if (req
== PTRACE_GETREGSET
)
922 return copy_regset_to_user(task
, view
, regset_no
, 0,
923 kiov
->iov_len
, kiov
->iov_base
);
925 return copy_regset_from_user(task
, view
, regset_no
, 0,
926 kiov
->iov_len
, kiov
->iov_base
);
930 * This is declared in linux/regset.h and defined in machine-dependent
931 * code. We put the export here, near the primary machine-neutral use,
932 * to ensure no machine forgets it.
934 EXPORT_SYMBOL_GPL(task_user_regset_view
);
937 ptrace_get_syscall_info_entry(struct task_struct
*child
, struct pt_regs
*regs
,
938 struct ptrace_syscall_info
*info
)
940 unsigned long args
[ARRAY_SIZE(info
->entry
.args
)];
943 info
->op
= PTRACE_SYSCALL_INFO_ENTRY
;
944 info
->entry
.nr
= syscall_get_nr(child
, regs
);
945 syscall_get_arguments(child
, regs
, args
);
946 for (i
= 0; i
< ARRAY_SIZE(args
); i
++)
947 info
->entry
.args
[i
] = args
[i
];
949 /* args is the last field in struct ptrace_syscall_info.entry */
950 return offsetofend(struct ptrace_syscall_info
, entry
.args
);
954 ptrace_get_syscall_info_seccomp(struct task_struct
*child
, struct pt_regs
*regs
,
955 struct ptrace_syscall_info
*info
)
958 * As struct ptrace_syscall_info.entry is currently a subset
959 * of struct ptrace_syscall_info.seccomp, it makes sense to
960 * initialize that subset using ptrace_get_syscall_info_entry().
961 * This can be reconsidered in the future if these structures
962 * diverge significantly enough.
964 ptrace_get_syscall_info_entry(child
, regs
, info
);
965 info
->op
= PTRACE_SYSCALL_INFO_SECCOMP
;
966 info
->seccomp
.ret_data
= child
->ptrace_message
;
968 /* ret_data is the last field in struct ptrace_syscall_info.seccomp */
969 return offsetofend(struct ptrace_syscall_info
, seccomp
.ret_data
);
973 ptrace_get_syscall_info_exit(struct task_struct
*child
, struct pt_regs
*regs
,
974 struct ptrace_syscall_info
*info
)
976 info
->op
= PTRACE_SYSCALL_INFO_EXIT
;
977 info
->exit
.rval
= syscall_get_error(child
, regs
);
978 info
->exit
.is_error
= !!info
->exit
.rval
;
979 if (!info
->exit
.is_error
)
980 info
->exit
.rval
= syscall_get_return_value(child
, regs
);
982 /* is_error is the last field in struct ptrace_syscall_info.exit */
983 return offsetofend(struct ptrace_syscall_info
, exit
.is_error
);
987 ptrace_get_syscall_info(struct task_struct
*child
, unsigned long user_size
,
990 struct pt_regs
*regs
= task_pt_regs(child
);
991 struct ptrace_syscall_info info
= {
992 .op
= PTRACE_SYSCALL_INFO_NONE
,
993 .arch
= syscall_get_arch(child
),
994 .instruction_pointer
= instruction_pointer(regs
),
995 .stack_pointer
= user_stack_pointer(regs
),
997 unsigned long actual_size
= offsetof(struct ptrace_syscall_info
, entry
);
998 unsigned long write_size
;
1001 * This does not need lock_task_sighand() to access
1002 * child->last_siginfo because ptrace_freeze_traced()
1003 * called earlier by ptrace_check_attach() ensures that
1004 * the tracee cannot go away and clear its last_siginfo.
1006 switch (child
->last_siginfo
? child
->last_siginfo
->si_code
: 0) {
1007 case SIGTRAP
| 0x80:
1008 switch (child
->ptrace_message
) {
1009 case PTRACE_EVENTMSG_SYSCALL_ENTRY
:
1010 actual_size
= ptrace_get_syscall_info_entry(child
, regs
,
1013 case PTRACE_EVENTMSG_SYSCALL_EXIT
:
1014 actual_size
= ptrace_get_syscall_info_exit(child
, regs
,
1019 case SIGTRAP
| (PTRACE_EVENT_SECCOMP
<< 8):
1020 actual_size
= ptrace_get_syscall_info_seccomp(child
, regs
,
1025 write_size
= min(actual_size
, user_size
);
1026 return copy_to_user(datavp
, &info
, write_size
) ? -EFAULT
: actual_size
;
1028 #endif /* CONFIG_HAVE_ARCH_TRACEHOOK */
1030 int ptrace_request(struct task_struct
*child
, long request
,
1031 unsigned long addr
, unsigned long data
)
1033 bool seized
= child
->ptrace
& PT_SEIZED
;
1035 kernel_siginfo_t siginfo
, *si
;
1036 void __user
*datavp
= (void __user
*) data
;
1037 unsigned long __user
*datalp
= datavp
;
1038 unsigned long flags
;
1041 case PTRACE_PEEKTEXT
:
1042 case PTRACE_PEEKDATA
:
1043 return generic_ptrace_peekdata(child
, addr
, data
);
1044 case PTRACE_POKETEXT
:
1045 case PTRACE_POKEDATA
:
1046 return generic_ptrace_pokedata(child
, addr
, data
);
1048 #ifdef PTRACE_OLDSETOPTIONS
1049 case PTRACE_OLDSETOPTIONS
:
1051 case PTRACE_SETOPTIONS
:
1052 ret
= ptrace_setoptions(child
, data
);
1054 case PTRACE_GETEVENTMSG
:
1055 ret
= put_user(child
->ptrace_message
, datalp
);
1058 case PTRACE_PEEKSIGINFO
:
1059 ret
= ptrace_peek_siginfo(child
, addr
, data
);
1062 case PTRACE_GETSIGINFO
:
1063 ret
= ptrace_getsiginfo(child
, &siginfo
);
1065 ret
= copy_siginfo_to_user(datavp
, &siginfo
);
1068 case PTRACE_SETSIGINFO
:
1069 ret
= copy_siginfo_from_user(&siginfo
, datavp
);
1071 ret
= ptrace_setsiginfo(child
, &siginfo
);
1074 case PTRACE_GETSIGMASK
: {
1077 if (addr
!= sizeof(sigset_t
)) {
1082 if (test_tsk_restore_sigmask(child
))
1083 mask
= &child
->saved_sigmask
;
1085 mask
= &child
->blocked
;
1087 if (copy_to_user(datavp
, mask
, sizeof(sigset_t
)))
1095 case PTRACE_SETSIGMASK
: {
1098 if (addr
!= sizeof(sigset_t
)) {
1103 if (copy_from_user(&new_set
, datavp
, sizeof(sigset_t
))) {
1108 sigdelsetmask(&new_set
, sigmask(SIGKILL
)|sigmask(SIGSTOP
));
1111 * Every thread does recalc_sigpending() after resume, so
1112 * retarget_shared_pending() and recalc_sigpending() are not
1115 spin_lock_irq(&child
->sighand
->siglock
);
1116 child
->blocked
= new_set
;
1117 spin_unlock_irq(&child
->sighand
->siglock
);
1119 clear_tsk_restore_sigmask(child
);
1125 case PTRACE_INTERRUPT
:
1127 * Stop tracee without any side-effect on signal or job
1128 * control. At least one trap is guaranteed to happen
1129 * after this request. If @child is already trapped, the
1130 * current trap is not disturbed and another trap will
1131 * happen after the current trap is ended with PTRACE_CONT.
1133 * The actual trap might not be PTRACE_EVENT_STOP trap but
1134 * the pending condition is cleared regardless.
1136 if (unlikely(!seized
|| !lock_task_sighand(child
, &flags
)))
1140 * INTERRUPT doesn't disturb existing trap sans one
1141 * exception. If ptracer issued LISTEN for the current
1142 * STOP, this INTERRUPT should clear LISTEN and re-trap
1145 if (likely(task_set_jobctl_pending(child
, JOBCTL_TRAP_STOP
)))
1146 ptrace_signal_wake_up(child
, child
->jobctl
& JOBCTL_LISTENING
);
1148 unlock_task_sighand(child
, &flags
);
1154 * Listen for events. Tracee must be in STOP. It's not
1155 * resumed per-se but is not considered to be in TRACED by
1156 * wait(2) or ptrace(2). If an async event (e.g. group
1157 * stop state change) happens, tracee will enter STOP trap
1158 * again. Alternatively, ptracer can issue INTERRUPT to
1159 * finish listening and re-trap tracee into STOP.
1161 if (unlikely(!seized
|| !lock_task_sighand(child
, &flags
)))
1164 si
= child
->last_siginfo
;
1165 if (likely(si
&& (si
->si_code
>> 8) == PTRACE_EVENT_STOP
)) {
1166 child
->jobctl
|= JOBCTL_LISTENING
;
1168 * If NOTIFY is set, it means event happened between
1169 * start of this trap and now. Trigger re-trap.
1171 if (child
->jobctl
& JOBCTL_TRAP_NOTIFY
)
1172 ptrace_signal_wake_up(child
, true);
1175 unlock_task_sighand(child
, &flags
);
1178 case PTRACE_DETACH
: /* detach a process that was attached. */
1179 ret
= ptrace_detach(child
, data
);
1182 #ifdef CONFIG_BINFMT_ELF_FDPIC
1183 case PTRACE_GETFDPIC
: {
1184 struct mm_struct
*mm
= get_task_mm(child
);
1185 unsigned long tmp
= 0;
1192 case PTRACE_GETFDPIC_EXEC
:
1193 tmp
= mm
->context
.exec_fdpic_loadmap
;
1195 case PTRACE_GETFDPIC_INTERP
:
1196 tmp
= mm
->context
.interp_fdpic_loadmap
;
1203 ret
= put_user(tmp
, datalp
);
1208 case PTRACE_SINGLESTEP
:
1209 #ifdef PTRACE_SINGLEBLOCK
1210 case PTRACE_SINGLEBLOCK
:
1212 #ifdef PTRACE_SYSEMU
1214 case PTRACE_SYSEMU_SINGLESTEP
:
1216 case PTRACE_SYSCALL
:
1218 return ptrace_resume(child
, request
, data
);
1221 send_sig_info(SIGKILL
, SEND_SIG_NOINFO
, child
);
1224 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1225 case PTRACE_GETREGSET
:
1226 case PTRACE_SETREGSET
: {
1228 struct iovec __user
*uiov
= datavp
;
1230 if (!access_ok(uiov
, sizeof(*uiov
)))
1233 if (__get_user(kiov
.iov_base
, &uiov
->iov_base
) ||
1234 __get_user(kiov
.iov_len
, &uiov
->iov_len
))
1237 ret
= ptrace_regset(child
, request
, addr
, &kiov
);
1239 ret
= __put_user(kiov
.iov_len
, &uiov
->iov_len
);
1243 case PTRACE_GET_SYSCALL_INFO
:
1244 ret
= ptrace_get_syscall_info(child
, addr
, datavp
);
1248 case PTRACE_SECCOMP_GET_FILTER
:
1249 ret
= seccomp_get_filter(child
, addr
, datavp
);
1252 case PTRACE_SECCOMP_GET_METADATA
:
1253 ret
= seccomp_get_metadata(child
, addr
, datavp
);
1257 case PTRACE_GET_RSEQ_CONFIGURATION
:
1258 ret
= ptrace_get_rseq_configuration(child
, addr
, datavp
);
1269 SYSCALL_DEFINE4(ptrace
, long, request
, long, pid
, unsigned long, addr
,
1270 unsigned long, data
)
1272 struct task_struct
*child
;
1275 if (request
== PTRACE_TRACEME
) {
1276 ret
= ptrace_traceme();
1280 child
= find_get_task_by_vpid(pid
);
1286 if (request
== PTRACE_ATTACH
|| request
== PTRACE_SEIZE
) {
1287 ret
= ptrace_attach(child
, request
, addr
, data
);
1288 goto out_put_task_struct
;
1291 ret
= ptrace_check_attach(child
, request
== PTRACE_KILL
||
1292 request
== PTRACE_INTERRUPT
);
1294 goto out_put_task_struct
;
1296 ret
= arch_ptrace(child
, request
, addr
, data
);
1297 if (ret
|| request
!= PTRACE_DETACH
)
1298 ptrace_unfreeze_traced(child
);
1300 out_put_task_struct
:
1301 put_task_struct(child
);
1306 int generic_ptrace_peekdata(struct task_struct
*tsk
, unsigned long addr
,
1312 copied
= ptrace_access_vm(tsk
, addr
, &tmp
, sizeof(tmp
), FOLL_FORCE
);
1313 if (copied
!= sizeof(tmp
))
1315 return put_user(tmp
, (unsigned long __user
*)data
);
1318 int generic_ptrace_pokedata(struct task_struct
*tsk
, unsigned long addr
,
1323 copied
= ptrace_access_vm(tsk
, addr
, &data
, sizeof(data
),
1324 FOLL_FORCE
| FOLL_WRITE
);
1325 return (copied
== sizeof(data
)) ? 0 : -EIO
;
1328 #if defined CONFIG_COMPAT
1330 int compat_ptrace_request(struct task_struct
*child
, compat_long_t request
,
1331 compat_ulong_t addr
, compat_ulong_t data
)
1333 compat_ulong_t __user
*datap
= compat_ptr(data
);
1334 compat_ulong_t word
;
1335 kernel_siginfo_t siginfo
;
1339 case PTRACE_PEEKTEXT
:
1340 case PTRACE_PEEKDATA
:
1341 ret
= ptrace_access_vm(child
, addr
, &word
, sizeof(word
),
1343 if (ret
!= sizeof(word
))
1346 ret
= put_user(word
, datap
);
1349 case PTRACE_POKETEXT
:
1350 case PTRACE_POKEDATA
:
1351 ret
= ptrace_access_vm(child
, addr
, &data
, sizeof(data
),
1352 FOLL_FORCE
| FOLL_WRITE
);
1353 ret
= (ret
!= sizeof(data
) ? -EIO
: 0);
1356 case PTRACE_GETEVENTMSG
:
1357 ret
= put_user((compat_ulong_t
) child
->ptrace_message
, datap
);
1360 case PTRACE_GETSIGINFO
:
1361 ret
= ptrace_getsiginfo(child
, &siginfo
);
1363 ret
= copy_siginfo_to_user32(
1364 (struct compat_siginfo __user
*) datap
,
1368 case PTRACE_SETSIGINFO
:
1369 ret
= copy_siginfo_from_user32(
1370 &siginfo
, (struct compat_siginfo __user
*) datap
);
1372 ret
= ptrace_setsiginfo(child
, &siginfo
);
1374 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1375 case PTRACE_GETREGSET
:
1376 case PTRACE_SETREGSET
:
1379 struct compat_iovec __user
*uiov
=
1380 (struct compat_iovec __user
*) datap
;
1384 if (!access_ok(uiov
, sizeof(*uiov
)))
1387 if (__get_user(ptr
, &uiov
->iov_base
) ||
1388 __get_user(len
, &uiov
->iov_len
))
1391 kiov
.iov_base
= compat_ptr(ptr
);
1394 ret
= ptrace_regset(child
, request
, addr
, &kiov
);
1396 ret
= __put_user(kiov
.iov_len
, &uiov
->iov_len
);
1402 ret
= ptrace_request(child
, request
, addr
, data
);
1408 COMPAT_SYSCALL_DEFINE4(ptrace
, compat_long_t
, request
, compat_long_t
, pid
,
1409 compat_long_t
, addr
, compat_long_t
, data
)
1411 struct task_struct
*child
;
1414 if (request
== PTRACE_TRACEME
) {
1415 ret
= ptrace_traceme();
1419 child
= find_get_task_by_vpid(pid
);
1425 if (request
== PTRACE_ATTACH
|| request
== PTRACE_SEIZE
) {
1426 ret
= ptrace_attach(child
, request
, addr
, data
);
1427 goto out_put_task_struct
;
1430 ret
= ptrace_check_attach(child
, request
== PTRACE_KILL
||
1431 request
== PTRACE_INTERRUPT
);
1433 ret
= compat_arch_ptrace(child
, request
, addr
, data
);
1434 if (ret
|| request
!= PTRACE_DETACH
)
1435 ptrace_unfreeze_traced(child
);
1438 out_put_task_struct
:
1439 put_task_struct(child
);
1443 #endif /* CONFIG_COMPAT */