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CommitLineData
1da177e4
LT
1/*
2 * linux/kernel/ptrace.c
3 *
4 * (C) Copyright 1999 Linus Torvalds
5 *
6 * Common interfaces for "ptrace()" which we do not want
7 * to continually duplicate across every architecture.
8 */
9
c59ede7b 10#include <linux/capability.h>
9984de1a 11#include <linux/export.h>
1da177e4
LT
12#include <linux/sched.h>
13#include <linux/errno.h>
14#include <linux/mm.h>
15#include <linux/highmem.h>
16#include <linux/pagemap.h>
1da177e4
LT
17#include <linux/ptrace.h>
18#include <linux/security.h>
7ed20e1a 19#include <linux/signal.h>
a27bb332 20#include <linux/uio.h>
a5cb013d 21#include <linux/audit.h>
b488893a 22#include <linux/pid_namespace.h>
f17d30a8 23#include <linux/syscalls.h>
3a709703 24#include <linux/uaccess.h>
2225a122 25#include <linux/regset.h>
bf26c018 26#include <linux/hw_breakpoint.h>
f701e5b7 27#include <linux/cn_proc.h>
84c751bd 28#include <linux/compat.h>
1da177e4 29
bf53de90 30
1da177e4
LT
31/*
32 * ptrace a task: make the debugger its new parent and
33 * move it to the ptrace list.
34 *
35 * Must be called with the tasklist lock write-held.
36 */
36c8b586 37void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
1da177e4 38{
f470021a
RM
39 BUG_ON(!list_empty(&child->ptrace_entry));
40 list_add(&child->ptrace_entry, &new_parent->ptraced);
1da177e4 41 child->parent = new_parent;
1da177e4 42}
3a709703 43
e3bd058f
TH
44/**
45 * __ptrace_unlink - unlink ptracee and restore its execution state
46 * @child: ptracee to be unlinked
1da177e4 47 *
0e9f0a4a
TH
48 * Remove @child from the ptrace list, move it back to the original parent,
49 * and restore the execution state so that it conforms to the group stop
50 * state.
51 *
52 * Unlinking can happen via two paths - explicit PTRACE_DETACH or ptracer
53 * exiting. For PTRACE_DETACH, unless the ptracee has been killed between
54 * ptrace_check_attach() and here, it's guaranteed to be in TASK_TRACED.
55 * If the ptracer is exiting, the ptracee can be in any state.
56 *
57 * After detach, the ptracee should be in a state which conforms to the
58 * group stop. If the group is stopped or in the process of stopping, the
59 * ptracee should be put into TASK_STOPPED; otherwise, it should be woken
60 * up from TASK_TRACED.
61 *
62 * If the ptracee is in TASK_TRACED and needs to be moved to TASK_STOPPED,
63 * it goes through TRACED -> RUNNING -> STOPPED transition which is similar
64 * to but in the opposite direction of what happens while attaching to a
65 * stopped task. However, in this direction, the intermediate RUNNING
66 * state is not hidden even from the current ptracer and if it immediately
67 * re-attaches and performs a WNOHANG wait(2), it may fail.
e3bd058f
TH
68 *
69 * CONTEXT:
70 * write_lock_irq(tasklist_lock)
1da177e4 71 */
36c8b586 72void __ptrace_unlink(struct task_struct *child)
1da177e4 73{
5ecfbae0
ON
74 BUG_ON(!child->ptrace);
75
1da177e4 76 child->ptrace = 0;
f470021a
RM
77 child->parent = child->real_parent;
78 list_del_init(&child->ptrace_entry);
1da177e4 79
1da177e4 80 spin_lock(&child->sighand->siglock);
0e9f0a4a 81
73ddff2b
TH
82 /*
83 * Clear all pending traps and TRAPPING. TRAPPING should be
84 * cleared regardless of JOBCTL_STOP_PENDING. Do it explicitly.
85 */
86 task_clear_jobctl_pending(child, JOBCTL_TRAP_MASK);
87 task_clear_jobctl_trapping(child);
88
0e9f0a4a 89 /*
a8f072c1 90 * Reinstate JOBCTL_STOP_PENDING if group stop is in effect and
0e9f0a4a
TH
91 * @child isn't dead.
92 */
93 if (!(child->flags & PF_EXITING) &&
94 (child->signal->flags & SIGNAL_STOP_STOPPED ||
8a88951b 95 child->signal->group_stop_count)) {
a8f072c1 96 child->jobctl |= JOBCTL_STOP_PENDING;
0e9f0a4a 97
8a88951b
ON
98 /*
99 * This is only possible if this thread was cloned by the
100 * traced task running in the stopped group, set the signal
101 * for the future reports.
102 * FIXME: we should change ptrace_init_task() to handle this
103 * case.
104 */
105 if (!(child->jobctl & JOBCTL_STOP_SIGMASK))
106 child->jobctl |= SIGSTOP;
107 }
108
0e9f0a4a
TH
109 /*
110 * If transition to TASK_STOPPED is pending or in TASK_TRACED, kick
111 * @child in the butt. Note that @resume should be used iff @child
112 * is in TASK_TRACED; otherwise, we might unduly disrupt
113 * TASK_KILLABLE sleeps.
114 */
a8f072c1 115 if (child->jobctl & JOBCTL_STOP_PENDING || task_is_traced(child))
910ffdb1 116 ptrace_signal_wake_up(child, true);
0e9f0a4a 117
1da177e4 118 spin_unlock(&child->sighand->siglock);
1da177e4
LT
119}
120
9899d11f
ON
121/* Ensure that nothing can wake it up, even SIGKILL */
122static bool ptrace_freeze_traced(struct task_struct *task)
123{
124 bool ret = false;
125
126 /* Lockless, nobody but us can set this flag */
127 if (task->jobctl & JOBCTL_LISTENING)
128 return ret;
129
130 spin_lock_irq(&task->sighand->siglock);
131 if (task_is_traced(task) && !__fatal_signal_pending(task)) {
132 task->state = __TASK_TRACED;
133 ret = true;
134 }
135 spin_unlock_irq(&task->sighand->siglock);
136
137 return ret;
138}
139
140static void ptrace_unfreeze_traced(struct task_struct *task)
141{
142 if (task->state != __TASK_TRACED)
143 return;
144
145 WARN_ON(!task->ptrace || task->parent != current);
146
147 spin_lock_irq(&task->sighand->siglock);
148 if (__fatal_signal_pending(task))
149 wake_up_state(task, __TASK_TRACED);
150 else
151 task->state = TASK_TRACED;
152 spin_unlock_irq(&task->sighand->siglock);
153}
154
755e276b
TH
155/**
156 * ptrace_check_attach - check whether ptracee is ready for ptrace operation
157 * @child: ptracee to check for
158 * @ignore_state: don't check whether @child is currently %TASK_TRACED
159 *
160 * Check whether @child is being ptraced by %current and ready for further
161 * ptrace operations. If @ignore_state is %false, @child also should be in
162 * %TASK_TRACED state and on return the child is guaranteed to be traced
163 * and not executing. If @ignore_state is %true, @child can be in any
164 * state.
165 *
166 * CONTEXT:
167 * Grabs and releases tasklist_lock and @child->sighand->siglock.
168 *
169 * RETURNS:
170 * 0 on success, -ESRCH if %child is not ready.
1da177e4 171 */
edea0d03 172static int ptrace_check_attach(struct task_struct *child, bool ignore_state)
1da177e4
LT
173{
174 int ret = -ESRCH;
175
176 /*
177 * We take the read lock around doing both checks to close a
178 * possible race where someone else was tracing our child and
179 * detached between these two checks. After this locked check,
180 * we are sure that this is our traced child and that can only
181 * be changed by us so it's not changing right after this.
182 */
183 read_lock(&tasklist_lock);
9899d11f
ON
184 if (child->ptrace && child->parent == current) {
185 WARN_ON(child->state == __TASK_TRACED);
c0c0b649
ON
186 /*
187 * child->sighand can't be NULL, release_task()
188 * does ptrace_unlink() before __exit_signal().
189 */
9899d11f 190 if (ignore_state || ptrace_freeze_traced(child))
321fb561 191 ret = 0;
1da177e4
LT
192 }
193 read_unlock(&tasklist_lock);
194
9899d11f
ON
195 if (!ret && !ignore_state) {
196 if (!wait_task_inactive(child, __TASK_TRACED)) {
197 /*
198 * This can only happen if may_ptrace_stop() fails and
199 * ptrace_stop() changes ->state back to TASK_RUNNING,
200 * so we should not worry about leaking __TASK_TRACED.
201 */
202 WARN_ON(child->state == __TASK_TRACED);
203 ret = -ESRCH;
204 }
205 }
1da177e4 206
1da177e4
LT
207 return ret;
208}
209
69f594a3
EP
210static int ptrace_has_cap(struct user_namespace *ns, unsigned int mode)
211{
212 if (mode & PTRACE_MODE_NOAUDIT)
213 return has_ns_capability_noaudit(current, ns, CAP_SYS_PTRACE);
214 else
215 return has_ns_capability(current, ns, CAP_SYS_PTRACE);
216}
217
9f99798f
TH
218/* Returns 0 on success, -errno on denial. */
219static int __ptrace_may_access(struct task_struct *task, unsigned int mode)
ab8d11be 220{
c69e8d9c 221 const struct cred *cred = current_cred(), *tcred;
b6dff3ec 222
df26c40e
EB
223 /* May we inspect the given task?
224 * This check is used both for attaching with ptrace
225 * and for allowing access to sensitive information in /proc.
226 *
227 * ptrace_attach denies several cases that /proc allows
228 * because setting up the necessary parent/child relationship
229 * or halting the specified task is impossible.
230 */
231 int dumpable = 0;
232 /* Don't let security modules deny introspection */
73af963f 233 if (same_thread_group(task, current))
df26c40e 234 return 0;
c69e8d9c
DH
235 rcu_read_lock();
236 tcred = __task_cred(task);
5af66203
EB
237 if (uid_eq(cred->uid, tcred->euid) &&
238 uid_eq(cred->uid, tcred->suid) &&
239 uid_eq(cred->uid, tcred->uid) &&
240 gid_eq(cred->gid, tcred->egid) &&
241 gid_eq(cred->gid, tcred->sgid) &&
242 gid_eq(cred->gid, tcred->gid))
8409cca7 243 goto ok;
c4a4d603 244 if (ptrace_has_cap(tcred->user_ns, mode))
8409cca7
SH
245 goto ok;
246 rcu_read_unlock();
247 return -EPERM;
248ok:
c69e8d9c 249 rcu_read_unlock();
ab8d11be 250 smp_rmb();
df26c40e 251 if (task->mm)
6c5d5238 252 dumpable = get_dumpable(task->mm);
4c44aaaf 253 rcu_read_lock();
d049f74f
KC
254 if (dumpable != SUID_DUMP_USER &&
255 !ptrace_has_cap(__task_cred(task)->user_ns, mode)) {
4c44aaaf 256 rcu_read_unlock();
ab8d11be 257 return -EPERM;
4c44aaaf
EB
258 }
259 rcu_read_unlock();
ab8d11be 260
9e48858f 261 return security_ptrace_access_check(task, mode);
ab8d11be
MS
262}
263
006ebb40 264bool ptrace_may_access(struct task_struct *task, unsigned int mode)
ab8d11be
MS
265{
266 int err;
267 task_lock(task);
006ebb40 268 err = __ptrace_may_access(task, mode);
ab8d11be 269 task_unlock(task);
3a709703 270 return !err;
ab8d11be
MS
271}
272
3544d72a 273static int ptrace_attach(struct task_struct *task, long request,
aa9147c9 274 unsigned long addr,
3544d72a 275 unsigned long flags)
1da177e4 276{
3544d72a 277 bool seize = (request == PTRACE_SEIZE);
1da177e4 278 int retval;
f5b40e36 279
3544d72a 280 retval = -EIO;
aa9147c9
DV
281 if (seize) {
282 if (addr != 0)
283 goto out;
aa9147c9
DV
284 if (flags & ~(unsigned long)PTRACE_O_MASK)
285 goto out;
286 flags = PT_PTRACED | PT_SEIZED | (flags << PT_OPT_FLAG_SHIFT);
287 } else {
288 flags = PT_PTRACED;
289 }
3544d72a 290
a5cb013d
AV
291 audit_ptrace(task);
292
1da177e4 293 retval = -EPERM;
b79b7ba9
ON
294 if (unlikely(task->flags & PF_KTHREAD))
295 goto out;
bac0abd6 296 if (same_thread_group(task, current))
f5b40e36
LT
297 goto out;
298
f2f0b00a
ON
299 /*
300 * Protect exec's credential calculations against our interference;
86b6c1f3 301 * SUID, SGID and LSM creds get determined differently
5e751e99 302 * under ptrace.
d84f4f99 303 */
793285fc 304 retval = -ERESTARTNOINTR;
9b1bf12d 305 if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
d84f4f99 306 goto out;
f5b40e36 307
4b105cbb 308 task_lock(task);
006ebb40 309 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
4b105cbb 310 task_unlock(task);
1da177e4 311 if (retval)
4b105cbb 312 goto unlock_creds;
1da177e4 313
4b105cbb 314 write_lock_irq(&tasklist_lock);
b79b7ba9
ON
315 retval = -EPERM;
316 if (unlikely(task->exit_state))
4b105cbb 317 goto unlock_tasklist;
f2f0b00a 318 if (task->ptrace)
4b105cbb 319 goto unlock_tasklist;
b79b7ba9 320
3544d72a 321 if (seize)
aa9147c9 322 flags |= PT_SEIZED;
4c44aaaf
EB
323 rcu_read_lock();
324 if (ns_capable(__task_cred(task)->user_ns, CAP_SYS_PTRACE))
aa9147c9 325 flags |= PT_PTRACE_CAP;
4c44aaaf 326 rcu_read_unlock();
aa9147c9 327 task->ptrace = flags;
1da177e4 328
1da177e4 329 __ptrace_link(task, current);
3544d72a
TH
330
331 /* SEIZE doesn't trap tracee on attach */
332 if (!seize)
333 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
b79b7ba9 334
d79fdd6d
TH
335 spin_lock(&task->sighand->siglock);
336
337 /*
73ddff2b 338 * If the task is already STOPPED, set JOBCTL_TRAP_STOP and
d79fdd6d
TH
339 * TRAPPING, and kick it so that it transits to TRACED. TRAPPING
340 * will be cleared if the child completes the transition or any
341 * event which clears the group stop states happens. We'll wait
342 * for the transition to complete before returning from this
343 * function.
344 *
345 * This hides STOPPED -> RUNNING -> TRACED transition from the
346 * attaching thread but a different thread in the same group can
347 * still observe the transient RUNNING state. IOW, if another
348 * thread's WNOHANG wait(2) on the stopped tracee races against
349 * ATTACH, the wait(2) may fail due to the transient RUNNING.
350 *
351 * The following task_is_stopped() test is safe as both transitions
352 * in and out of STOPPED are protected by siglock.
353 */
7dd3db54 354 if (task_is_stopped(task) &&
73ddff2b 355 task_set_jobctl_pending(task, JOBCTL_TRAP_STOP | JOBCTL_TRAPPING))
910ffdb1 356 signal_wake_up_state(task, __TASK_STOPPED);
d79fdd6d
TH
357
358 spin_unlock(&task->sighand->siglock);
359
b79b7ba9 360 retval = 0;
4b105cbb
ON
361unlock_tasklist:
362 write_unlock_irq(&tasklist_lock);
363unlock_creds:
9b1bf12d 364 mutex_unlock(&task->signal->cred_guard_mutex);
f5b40e36 365out:
f701e5b7 366 if (!retval) {
62c124ff 367 wait_on_bit(&task->jobctl, JOBCTL_TRAPPING_BIT,
74316201 368 TASK_UNINTERRUPTIBLE);
f701e5b7
VZ
369 proc_ptrace_connector(task, PTRACE_ATTACH);
370 }
371
1da177e4
LT
372 return retval;
373}
374
f2f0b00a
ON
375/**
376 * ptrace_traceme -- helper for PTRACE_TRACEME
377 *
378 * Performs checks and sets PT_PTRACED.
379 * Should be used by all ptrace implementations for PTRACE_TRACEME.
380 */
e3e89cc5 381static int ptrace_traceme(void)
f2f0b00a
ON
382{
383 int ret = -EPERM;
384
4b105cbb
ON
385 write_lock_irq(&tasklist_lock);
386 /* Are we already being traced? */
f2f0b00a 387 if (!current->ptrace) {
f2f0b00a 388 ret = security_ptrace_traceme(current->parent);
f2f0b00a
ON
389 /*
390 * Check PF_EXITING to ensure ->real_parent has not passed
391 * exit_ptrace(). Otherwise we don't report the error but
392 * pretend ->real_parent untraces us right after return.
393 */
394 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
395 current->ptrace = PT_PTRACED;
396 __ptrace_link(current, current->real_parent);
397 }
f2f0b00a 398 }
4b105cbb
ON
399 write_unlock_irq(&tasklist_lock);
400
f2f0b00a
ON
401 return ret;
402}
403
39c626ae
ON
404/*
405 * Called with irqs disabled, returns true if childs should reap themselves.
406 */
407static int ignoring_children(struct sighand_struct *sigh)
408{
409 int ret;
410 spin_lock(&sigh->siglock);
411 ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
412 (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
413 spin_unlock(&sigh->siglock);
414 return ret;
415}
416
417/*
418 * Called with tasklist_lock held for writing.
419 * Unlink a traced task, and clean it up if it was a traced zombie.
420 * Return true if it needs to be reaped with release_task().
421 * (We can't call release_task() here because we already hold tasklist_lock.)
422 *
423 * If it's a zombie, our attachedness prevented normal parent notification
424 * or self-reaping. Do notification now if it would have happened earlier.
425 * If it should reap itself, return true.
426 *
a7f0765e
ON
427 * If it's our own child, there is no notification to do. But if our normal
428 * children self-reap, then this child was prevented by ptrace and we must
429 * reap it now, in that case we must also wake up sub-threads sleeping in
430 * do_wait().
39c626ae
ON
431 */
432static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
433{
9843a1e9
ON
434 bool dead;
435
39c626ae
ON
436 __ptrace_unlink(p);
437
9843a1e9
ON
438 if (p->exit_state != EXIT_ZOMBIE)
439 return false;
440
441 dead = !thread_group_leader(p);
442
443 if (!dead && thread_group_empty(p)) {
444 if (!same_thread_group(p->real_parent, tracer))
445 dead = do_notify_parent(p, p->exit_signal);
446 else if (ignoring_children(tracer->sighand)) {
447 __wake_up_parent(p, tracer);
9843a1e9 448 dead = true;
39c626ae
ON
449 }
450 }
9843a1e9
ON
451 /* Mark it as in the process of being reaped. */
452 if (dead)
453 p->exit_state = EXIT_DEAD;
454 return dead;
39c626ae
ON
455}
456
e3e89cc5 457static int ptrace_detach(struct task_struct *child, unsigned int data)
1da177e4 458{
7ed20e1a 459 if (!valid_signal(data))
5ecfbae0 460 return -EIO;
1da177e4
LT
461
462 /* Architecture-specific hardware disable .. */
463 ptrace_disable(child);
7d941432 464 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
1da177e4 465
95c3eb76 466 write_lock_irq(&tasklist_lock);
39c626ae 467 /*
64a4096c
ON
468 * We rely on ptrace_freeze_traced(). It can't be killed and
469 * untraced by another thread, it can't be a zombie.
39c626ae 470 */
64a4096c
ON
471 WARN_ON(!child->ptrace || child->exit_state);
472 /*
473 * tasklist_lock avoids the race with wait_task_stopped(), see
474 * the comment in ptrace_resume().
475 */
476 child->exit_code = data;
477 __ptrace_detach(current, child);
1da177e4
LT
478 write_unlock_irq(&tasklist_lock);
479
f701e5b7 480 proc_ptrace_connector(child, PTRACE_DETACH);
4576145c 481
1da177e4
LT
482 return 0;
483}
484
39c626ae 485/*
c7e49c14 486 * Detach all tasks we were using ptrace on. Called with tasklist held
7c8bd232 487 * for writing.
39c626ae 488 */
7c8bd232 489void exit_ptrace(struct task_struct *tracer, struct list_head *dead)
39c626ae
ON
490{
491 struct task_struct *p, *n;
c7e49c14 492
39c626ae 493 list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
992fb6e1
ON
494 if (unlikely(p->ptrace & PT_EXITKILL))
495 send_sig_info(SIGKILL, SEND_SIG_FORCED, p);
496
39c626ae 497 if (__ptrace_detach(tracer, p))
7c8bd232 498 list_add(&p->ptrace_entry, dead);
39c626ae
ON
499 }
500}
501
1da177e4
LT
502int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
503{
504 int copied = 0;
505
506 while (len > 0) {
507 char buf[128];
508 int this_len, retval;
509
510 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
511 retval = access_process_vm(tsk, src, buf, this_len, 0);
512 if (!retval) {
513 if (copied)
514 break;
515 return -EIO;
516 }
517 if (copy_to_user(dst, buf, retval))
518 return -EFAULT;
519 copied += retval;
520 src += retval;
521 dst += retval;
3a709703 522 len -= retval;
1da177e4
LT
523 }
524 return copied;
525}
526
527int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
528{
529 int copied = 0;
530
531 while (len > 0) {
532 char buf[128];
533 int this_len, retval;
534
535 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
536 if (copy_from_user(buf, src, this_len))
537 return -EFAULT;
538 retval = access_process_vm(tsk, dst, buf, this_len, 1);
539 if (!retval) {
540 if (copied)
541 break;
542 return -EIO;
543 }
544 copied += retval;
545 src += retval;
546 dst += retval;
3a709703 547 len -= retval;
1da177e4
LT
548 }
549 return copied;
550}
551
4abf9869 552static int ptrace_setoptions(struct task_struct *child, unsigned long data)
1da177e4 553{
86b6c1f3
DV
554 unsigned flags;
555
8c5cf9e5
DV
556 if (data & ~(unsigned long)PTRACE_O_MASK)
557 return -EINVAL;
558
86b6c1f3
DV
559 /* Avoid intermediate state when all opts are cleared */
560 flags = child->ptrace;
561 flags &= ~(PTRACE_O_MASK << PT_OPT_FLAG_SHIFT);
562 flags |= (data << PT_OPT_FLAG_SHIFT);
563 child->ptrace = flags;
1da177e4 564
8c5cf9e5 565 return 0;
1da177e4
LT
566}
567
e16b2781 568static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
1da177e4 569{
e4961254 570 unsigned long flags;
1da177e4
LT
571 int error = -ESRCH;
572
e4961254 573 if (lock_task_sighand(child, &flags)) {
1da177e4 574 error = -EINVAL;
1da177e4 575 if (likely(child->last_siginfo != NULL)) {
e16b2781 576 *info = *child->last_siginfo;
1da177e4
LT
577 error = 0;
578 }
e4961254 579 unlock_task_sighand(child, &flags);
1da177e4 580 }
1da177e4
LT
581 return error;
582}
583
e16b2781 584static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
1da177e4 585{
e4961254 586 unsigned long flags;
1da177e4
LT
587 int error = -ESRCH;
588
e4961254 589 if (lock_task_sighand(child, &flags)) {
1da177e4 590 error = -EINVAL;
1da177e4 591 if (likely(child->last_siginfo != NULL)) {
e16b2781 592 *child->last_siginfo = *info;
1da177e4
LT
593 error = 0;
594 }
e4961254 595 unlock_task_sighand(child, &flags);
1da177e4 596 }
1da177e4
LT
597 return error;
598}
599
84c751bd
AV
600static int ptrace_peek_siginfo(struct task_struct *child,
601 unsigned long addr,
602 unsigned long data)
603{
604 struct ptrace_peeksiginfo_args arg;
605 struct sigpending *pending;
606 struct sigqueue *q;
607 int ret, i;
608
609 ret = copy_from_user(&arg, (void __user *) addr,
610 sizeof(struct ptrace_peeksiginfo_args));
611 if (ret)
612 return -EFAULT;
613
614 if (arg.flags & ~PTRACE_PEEKSIGINFO_SHARED)
615 return -EINVAL; /* unknown flags */
616
617 if (arg.nr < 0)
618 return -EINVAL;
619
620 if (arg.flags & PTRACE_PEEKSIGINFO_SHARED)
621 pending = &child->signal->shared_pending;
622 else
623 pending = &child->pending;
624
625 for (i = 0; i < arg.nr; ) {
626 siginfo_t info;
627 s32 off = arg.off + i;
628
629 spin_lock_irq(&child->sighand->siglock);
630 list_for_each_entry(q, &pending->list, list) {
631 if (!off--) {
632 copy_siginfo(&info, &q->info);
633 break;
634 }
635 }
636 spin_unlock_irq(&child->sighand->siglock);
637
638 if (off >= 0) /* beyond the end of the list */
639 break;
640
641#ifdef CONFIG_COMPAT
642 if (unlikely(is_compat_task())) {
643 compat_siginfo_t __user *uinfo = compat_ptr(data);
644
706b23bd
MD
645 if (copy_siginfo_to_user32(uinfo, &info) ||
646 __put_user(info.si_code, &uinfo->si_code)) {
647 ret = -EFAULT;
648 break;
649 }
650
84c751bd
AV
651 } else
652#endif
653 {
654 siginfo_t __user *uinfo = (siginfo_t __user *) data;
655
706b23bd
MD
656 if (copy_siginfo_to_user(uinfo, &info) ||
657 __put_user(info.si_code, &uinfo->si_code)) {
658 ret = -EFAULT;
659 break;
660 }
84c751bd
AV
661 }
662
663 data += sizeof(siginfo_t);
664 i++;
665
666 if (signal_pending(current))
667 break;
668
669 cond_resched();
670 }
671
672 if (i > 0)
673 return i;
674
675 return ret;
676}
36df29d7
RM
677
678#ifdef PTRACE_SINGLESTEP
679#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
680#else
681#define is_singlestep(request) 0
682#endif
683
5b88abbf
RM
684#ifdef PTRACE_SINGLEBLOCK
685#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
686#else
687#define is_singleblock(request) 0
688#endif
689
36df29d7
RM
690#ifdef PTRACE_SYSEMU
691#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
692#else
693#define is_sysemu_singlestep(request) 0
694#endif
695
4abf9869
NK
696static int ptrace_resume(struct task_struct *child, long request,
697 unsigned long data)
36df29d7 698{
b72c1869
ON
699 bool need_siglock;
700
36df29d7
RM
701 if (!valid_signal(data))
702 return -EIO;
703
704 if (request == PTRACE_SYSCALL)
705 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
706 else
707 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
708
709#ifdef TIF_SYSCALL_EMU
710 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
711 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
712 else
713 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
714#endif
715
5b88abbf
RM
716 if (is_singleblock(request)) {
717 if (unlikely(!arch_has_block_step()))
718 return -EIO;
719 user_enable_block_step(child);
720 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
36df29d7
RM
721 if (unlikely(!arch_has_single_step()))
722 return -EIO;
723 user_enable_single_step(child);
3a709703 724 } else {
36df29d7 725 user_disable_single_step(child);
3a709703 726 }
36df29d7 727
b72c1869
ON
728 /*
729 * Change ->exit_code and ->state under siglock to avoid the race
730 * with wait_task_stopped() in between; a non-zero ->exit_code will
731 * wrongly look like another report from tracee.
732 *
733 * Note that we need siglock even if ->exit_code == data and/or this
734 * status was not reported yet, the new status must not be cleared by
735 * wait_task_stopped() after resume.
736 *
737 * If data == 0 we do not care if wait_task_stopped() reports the old
738 * status and clears the code too; this can't race with the tracee, it
739 * takes siglock after resume.
740 */
741 need_siglock = data && !thread_group_empty(current);
742 if (need_siglock)
743 spin_lock_irq(&child->sighand->siglock);
36df29d7 744 child->exit_code = data;
0666fb51 745 wake_up_state(child, __TASK_TRACED);
b72c1869
ON
746 if (need_siglock)
747 spin_unlock_irq(&child->sighand->siglock);
36df29d7
RM
748
749 return 0;
750}
751
2225a122
SS
752#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
753
754static const struct user_regset *
755find_regset(const struct user_regset_view *view, unsigned int type)
756{
757 const struct user_regset *regset;
758 int n;
759
760 for (n = 0; n < view->n; ++n) {
761 regset = view->regsets + n;
762 if (regset->core_note_type == type)
763 return regset;
764 }
765
766 return NULL;
767}
768
769static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
770 struct iovec *kiov)
771{
772 const struct user_regset_view *view = task_user_regset_view(task);
773 const struct user_regset *regset = find_regset(view, type);
774 int regset_no;
775
776 if (!regset || (kiov->iov_len % regset->size) != 0)
c6a0dd7e 777 return -EINVAL;
2225a122
SS
778
779 regset_no = regset - view->regsets;
780 kiov->iov_len = min(kiov->iov_len,
781 (__kernel_size_t) (regset->n * regset->size));
782
783 if (req == PTRACE_GETREGSET)
784 return copy_regset_to_user(task, view, regset_no, 0,
785 kiov->iov_len, kiov->iov_base);
786 else
787 return copy_regset_from_user(task, view, regset_no, 0,
788 kiov->iov_len, kiov->iov_base);
789}
790
e8440c14
JS
791/*
792 * This is declared in linux/regset.h and defined in machine-dependent
793 * code. We put the export here, near the primary machine-neutral use,
794 * to ensure no machine forgets it.
795 */
796EXPORT_SYMBOL_GPL(task_user_regset_view);
2225a122
SS
797#endif
798
1da177e4 799int ptrace_request(struct task_struct *child, long request,
4abf9869 800 unsigned long addr, unsigned long data)
1da177e4 801{
fca26f26 802 bool seized = child->ptrace & PT_SEIZED;
1da177e4 803 int ret = -EIO;
544b2c91 804 siginfo_t siginfo, *si;
9fed81dc
NK
805 void __user *datavp = (void __user *) data;
806 unsigned long __user *datalp = datavp;
fca26f26 807 unsigned long flags;
1da177e4
LT
808
809 switch (request) {
16c3e389
RM
810 case PTRACE_PEEKTEXT:
811 case PTRACE_PEEKDATA:
812 return generic_ptrace_peekdata(child, addr, data);
813 case PTRACE_POKETEXT:
814 case PTRACE_POKEDATA:
815 return generic_ptrace_pokedata(child, addr, data);
816
1da177e4
LT
817#ifdef PTRACE_OLDSETOPTIONS
818 case PTRACE_OLDSETOPTIONS:
819#endif
820 case PTRACE_SETOPTIONS:
821 ret = ptrace_setoptions(child, data);
822 break;
823 case PTRACE_GETEVENTMSG:
9fed81dc 824 ret = put_user(child->ptrace_message, datalp);
1da177e4 825 break;
e16b2781 826
84c751bd
AV
827 case PTRACE_PEEKSIGINFO:
828 ret = ptrace_peek_siginfo(child, addr, data);
829 break;
830
1da177e4 831 case PTRACE_GETSIGINFO:
e16b2781
RM
832 ret = ptrace_getsiginfo(child, &siginfo);
833 if (!ret)
9fed81dc 834 ret = copy_siginfo_to_user(datavp, &siginfo);
1da177e4 835 break;
e16b2781 836
1da177e4 837 case PTRACE_SETSIGINFO:
9fed81dc 838 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
e16b2781
RM
839 ret = -EFAULT;
840 else
841 ret = ptrace_setsiginfo(child, &siginfo);
1da177e4 842 break;
e16b2781 843
29000cae
AV
844 case PTRACE_GETSIGMASK:
845 if (addr != sizeof(sigset_t)) {
846 ret = -EINVAL;
847 break;
848 }
849
850 if (copy_to_user(datavp, &child->blocked, sizeof(sigset_t)))
851 ret = -EFAULT;
852 else
853 ret = 0;
854
855 break;
856
857 case PTRACE_SETSIGMASK: {
858 sigset_t new_set;
859
860 if (addr != sizeof(sigset_t)) {
861 ret = -EINVAL;
862 break;
863 }
864
865 if (copy_from_user(&new_set, datavp, sizeof(sigset_t))) {
866 ret = -EFAULT;
867 break;
868 }
869
870 sigdelsetmask(&new_set, sigmask(SIGKILL)|sigmask(SIGSTOP));
871
872 /*
873 * Every thread does recalc_sigpending() after resume, so
874 * retarget_shared_pending() and recalc_sigpending() are not
875 * called here.
876 */
877 spin_lock_irq(&child->sighand->siglock);
878 child->blocked = new_set;
879 spin_unlock_irq(&child->sighand->siglock);
880
881 ret = 0;
882 break;
883 }
884
fca26f26
TH
885 case PTRACE_INTERRUPT:
886 /*
887 * Stop tracee without any side-effect on signal or job
888 * control. At least one trap is guaranteed to happen
889 * after this request. If @child is already trapped, the
890 * current trap is not disturbed and another trap will
891 * happen after the current trap is ended with PTRACE_CONT.
892 *
893 * The actual trap might not be PTRACE_EVENT_STOP trap but
894 * the pending condition is cleared regardless.
895 */
896 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
897 break;
898
544b2c91
TH
899 /*
900 * INTERRUPT doesn't disturb existing trap sans one
901 * exception. If ptracer issued LISTEN for the current
902 * STOP, this INTERRUPT should clear LISTEN and re-trap
903 * tracee into STOP.
904 */
fca26f26 905 if (likely(task_set_jobctl_pending(child, JOBCTL_TRAP_STOP)))
910ffdb1 906 ptrace_signal_wake_up(child, child->jobctl & JOBCTL_LISTENING);
544b2c91
TH
907
908 unlock_task_sighand(child, &flags);
909 ret = 0;
910 break;
911
912 case PTRACE_LISTEN:
913 /*
914 * Listen for events. Tracee must be in STOP. It's not
915 * resumed per-se but is not considered to be in TRACED by
916 * wait(2) or ptrace(2). If an async event (e.g. group
917 * stop state change) happens, tracee will enter STOP trap
918 * again. Alternatively, ptracer can issue INTERRUPT to
919 * finish listening and re-trap tracee into STOP.
920 */
921 if (unlikely(!seized || !lock_task_sighand(child, &flags)))
922 break;
923
924 si = child->last_siginfo;
f9d81f61
ON
925 if (likely(si && (si->si_code >> 8) == PTRACE_EVENT_STOP)) {
926 child->jobctl |= JOBCTL_LISTENING;
927 /*
928 * If NOTIFY is set, it means event happened between
929 * start of this trap and now. Trigger re-trap.
930 */
931 if (child->jobctl & JOBCTL_TRAP_NOTIFY)
910ffdb1 932 ptrace_signal_wake_up(child, true);
f9d81f61
ON
933 ret = 0;
934 }
fca26f26 935 unlock_task_sighand(child, &flags);
fca26f26
TH
936 break;
937
1bcf5482
AD
938 case PTRACE_DETACH: /* detach a process that was attached. */
939 ret = ptrace_detach(child, data);
940 break;
36df29d7 941
9c1a1259
MF
942#ifdef CONFIG_BINFMT_ELF_FDPIC
943 case PTRACE_GETFDPIC: {
e0129ef9 944 struct mm_struct *mm = get_task_mm(child);
9c1a1259
MF
945 unsigned long tmp = 0;
946
e0129ef9
ON
947 ret = -ESRCH;
948 if (!mm)
949 break;
950
9c1a1259
MF
951 switch (addr) {
952 case PTRACE_GETFDPIC_EXEC:
e0129ef9 953 tmp = mm->context.exec_fdpic_loadmap;
9c1a1259
MF
954 break;
955 case PTRACE_GETFDPIC_INTERP:
e0129ef9 956 tmp = mm->context.interp_fdpic_loadmap;
9c1a1259
MF
957 break;
958 default:
959 break;
960 }
e0129ef9 961 mmput(mm);
9c1a1259 962
9fed81dc 963 ret = put_user(tmp, datalp);
9c1a1259
MF
964 break;
965 }
966#endif
967
36df29d7
RM
968#ifdef PTRACE_SINGLESTEP
969 case PTRACE_SINGLESTEP:
970#endif
5b88abbf
RM
971#ifdef PTRACE_SINGLEBLOCK
972 case PTRACE_SINGLEBLOCK:
973#endif
36df29d7
RM
974#ifdef PTRACE_SYSEMU
975 case PTRACE_SYSEMU:
976 case PTRACE_SYSEMU_SINGLESTEP:
977#endif
978 case PTRACE_SYSCALL:
979 case PTRACE_CONT:
980 return ptrace_resume(child, request, data);
981
982 case PTRACE_KILL:
983 if (child->exit_state) /* already dead */
984 return 0;
985 return ptrace_resume(child, request, SIGKILL);
986
2225a122
SS
987#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
988 case PTRACE_GETREGSET:
29000cae 989 case PTRACE_SETREGSET: {
2225a122 990 struct iovec kiov;
9fed81dc 991 struct iovec __user *uiov = datavp;
2225a122
SS
992
993 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
994 return -EFAULT;
995
996 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
997 __get_user(kiov.iov_len, &uiov->iov_len))
998 return -EFAULT;
999
1000 ret = ptrace_regset(child, request, addr, &kiov);
1001 if (!ret)
1002 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1003 break;
1004 }
1005#endif
1da177e4
LT
1006 default:
1007 break;
1008 }
1009
1010 return ret;
1011}
481bed45 1012
8053bdd5 1013static struct task_struct *ptrace_get_task_struct(pid_t pid)
6b9c7ed8
CH
1014{
1015 struct task_struct *child;
481bed45 1016
8053bdd5 1017 rcu_read_lock();
228ebcbe 1018 child = find_task_by_vpid(pid);
481bed45
CH
1019 if (child)
1020 get_task_struct(child);
8053bdd5 1021 rcu_read_unlock();
f400e198 1022
481bed45 1023 if (!child)
6b9c7ed8
CH
1024 return ERR_PTR(-ESRCH);
1025 return child;
481bed45
CH
1026}
1027
0ac15559
CH
1028#ifndef arch_ptrace_attach
1029#define arch_ptrace_attach(child) do { } while (0)
1030#endif
1031
4abf9869
NK
1032SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
1033 unsigned long, data)
481bed45
CH
1034{
1035 struct task_struct *child;
1036 long ret;
1037
6b9c7ed8
CH
1038 if (request == PTRACE_TRACEME) {
1039 ret = ptrace_traceme();
6ea6dd93
HS
1040 if (!ret)
1041 arch_ptrace_attach(current);
481bed45 1042 goto out;
6b9c7ed8
CH
1043 }
1044
1045 child = ptrace_get_task_struct(pid);
1046 if (IS_ERR(child)) {
1047 ret = PTR_ERR(child);
1048 goto out;
1049 }
481bed45 1050
3544d72a 1051 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
aa9147c9 1052 ret = ptrace_attach(child, request, addr, data);
0ac15559
CH
1053 /*
1054 * Some architectures need to do book-keeping after
1055 * a ptrace attach.
1056 */
1057 if (!ret)
1058 arch_ptrace_attach(child);
005f18df 1059 goto out_put_task_struct;
481bed45
CH
1060 }
1061
fca26f26
TH
1062 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1063 request == PTRACE_INTERRUPT);
481bed45
CH
1064 if (ret < 0)
1065 goto out_put_task_struct;
1066
1067 ret = arch_ptrace(child, request, addr, data);
9899d11f
ON
1068 if (ret || request != PTRACE_DETACH)
1069 ptrace_unfreeze_traced(child);
481bed45
CH
1070
1071 out_put_task_struct:
1072 put_task_struct(child);
1073 out:
481bed45
CH
1074 return ret;
1075}
76647323 1076
4abf9869
NK
1077int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
1078 unsigned long data)
76647323
AD
1079{
1080 unsigned long tmp;
1081 int copied;
1082
1083 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
1084 if (copied != sizeof(tmp))
1085 return -EIO;
1086 return put_user(tmp, (unsigned long __user *)data);
1087}
f284ce72 1088
4abf9869
NK
1089int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
1090 unsigned long data)
f284ce72
AD
1091{
1092 int copied;
1093
1094 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
1095 return (copied == sizeof(data)) ? 0 : -EIO;
1096}
032d82d9 1097
96b8936a 1098#if defined CONFIG_COMPAT
032d82d9
RM
1099
1100int compat_ptrace_request(struct task_struct *child, compat_long_t request,
1101 compat_ulong_t addr, compat_ulong_t data)
1102{
1103 compat_ulong_t __user *datap = compat_ptr(data);
1104 compat_ulong_t word;
e16b2781 1105 siginfo_t siginfo;
032d82d9
RM
1106 int ret;
1107
1108 switch (request) {
1109 case PTRACE_PEEKTEXT:
1110 case PTRACE_PEEKDATA:
1111 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
1112 if (ret != sizeof(word))
1113 ret = -EIO;
1114 else
1115 ret = put_user(word, datap);
1116 break;
1117
1118 case PTRACE_POKETEXT:
1119 case PTRACE_POKEDATA:
1120 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
1121 ret = (ret != sizeof(data) ? -EIO : 0);
1122 break;
1123
1124 case PTRACE_GETEVENTMSG:
1125 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
1126 break;
1127
e16b2781
RM
1128 case PTRACE_GETSIGINFO:
1129 ret = ptrace_getsiginfo(child, &siginfo);
1130 if (!ret)
1131 ret = copy_siginfo_to_user32(
1132 (struct compat_siginfo __user *) datap,
1133 &siginfo);
1134 break;
1135
1136 case PTRACE_SETSIGINFO:
1137 memset(&siginfo, 0, sizeof siginfo);
1138 if (copy_siginfo_from_user32(
1139 &siginfo, (struct compat_siginfo __user *) datap))
1140 ret = -EFAULT;
1141 else
1142 ret = ptrace_setsiginfo(child, &siginfo);
1143 break;
2225a122
SS
1144#ifdef CONFIG_HAVE_ARCH_TRACEHOOK
1145 case PTRACE_GETREGSET:
1146 case PTRACE_SETREGSET:
1147 {
1148 struct iovec kiov;
1149 struct compat_iovec __user *uiov =
1150 (struct compat_iovec __user *) datap;
1151 compat_uptr_t ptr;
1152 compat_size_t len;
1153
1154 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
1155 return -EFAULT;
1156
1157 if (__get_user(ptr, &uiov->iov_base) ||
1158 __get_user(len, &uiov->iov_len))
1159 return -EFAULT;
1160
1161 kiov.iov_base = compat_ptr(ptr);
1162 kiov.iov_len = len;
1163
1164 ret = ptrace_regset(child, request, addr, &kiov);
1165 if (!ret)
1166 ret = __put_user(kiov.iov_len, &uiov->iov_len);
1167 break;
1168 }
1169#endif
e16b2781 1170
032d82d9
RM
1171 default:
1172 ret = ptrace_request(child, request, addr, data);
1173 }
1174
1175 return ret;
1176}
c269f196 1177
62a6fa97
HC
1178COMPAT_SYSCALL_DEFINE4(ptrace, compat_long_t, request, compat_long_t, pid,
1179 compat_long_t, addr, compat_long_t, data)
c269f196
RM
1180{
1181 struct task_struct *child;
1182 long ret;
1183
c269f196
RM
1184 if (request == PTRACE_TRACEME) {
1185 ret = ptrace_traceme();
1186 goto out;
1187 }
1188
1189 child = ptrace_get_task_struct(pid);
1190 if (IS_ERR(child)) {
1191 ret = PTR_ERR(child);
1192 goto out;
1193 }
1194
3544d72a 1195 if (request == PTRACE_ATTACH || request == PTRACE_SEIZE) {
aa9147c9 1196 ret = ptrace_attach(child, request, addr, data);
c269f196
RM
1197 /*
1198 * Some architectures need to do book-keeping after
1199 * a ptrace attach.
1200 */
1201 if (!ret)
1202 arch_ptrace_attach(child);
1203 goto out_put_task_struct;
1204 }
1205
fca26f26
TH
1206 ret = ptrace_check_attach(child, request == PTRACE_KILL ||
1207 request == PTRACE_INTERRUPT);
9899d11f 1208 if (!ret) {
c269f196 1209 ret = compat_arch_ptrace(child, request, addr, data);
9899d11f
ON
1210 if (ret || request != PTRACE_DETACH)
1211 ptrace_unfreeze_traced(child);
1212 }
c269f196
RM
1213
1214 out_put_task_struct:
1215 put_task_struct(child);
1216 out:
c269f196
RM
1217 return ret;
1218}
96b8936a 1219#endif /* CONFIG_COMPAT */