userns: allow ptrace from non-init user namespaces
[linux-3.10.git] / kernel / ptrace.c
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
10 #include <linux/capability.h>
11 #include <linux/module.h>
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>
17 #include <linux/ptrace.h>
18 #include <linux/security.h>
19 #include <linux/signal.h>
20 #include <linux/audit.h>
21 #include <linux/pid_namespace.h>
22 #include <linux/syscalls.h>
23 #include <linux/uaccess.h>
24 #include <linux/regset.h>
25
26
27 /*
28  * ptrace a task: make the debugger its new parent and
29  * move it to the ptrace list.
30  *
31  * Must be called with the tasklist lock write-held.
32  */
33 void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
34 {
35         BUG_ON(!list_empty(&child->ptrace_entry));
36         list_add(&child->ptrace_entry, &new_parent->ptraced);
37         child->parent = new_parent;
38 }
39
40 /*
41  * Turn a tracing stop into a normal stop now, since with no tracer there
42  * would be no way to wake it up with SIGCONT or SIGKILL.  If there was a
43  * signal sent that would resume the child, but didn't because it was in
44  * TASK_TRACED, resume it now.
45  * Requires that irqs be disabled.
46  */
47 static void ptrace_untrace(struct task_struct *child)
48 {
49         spin_lock(&child->sighand->siglock);
50         if (task_is_traced(child)) {
51                 /*
52                  * If the group stop is completed or in progress,
53                  * this thread was already counted as stopped.
54                  */
55                 if (child->signal->flags & SIGNAL_STOP_STOPPED ||
56                     child->signal->group_stop_count)
57                         __set_task_state(child, TASK_STOPPED);
58                 else
59                         signal_wake_up(child, 1);
60         }
61         spin_unlock(&child->sighand->siglock);
62 }
63
64 /*
65  * unptrace a task: move it back to its original parent and
66  * remove it from the ptrace list.
67  *
68  * Must be called with the tasklist lock write-held.
69  */
70 void __ptrace_unlink(struct task_struct *child)
71 {
72         BUG_ON(!child->ptrace);
73
74         child->ptrace = 0;
75         child->parent = child->real_parent;
76         list_del_init(&child->ptrace_entry);
77
78         if (task_is_traced(child))
79                 ptrace_untrace(child);
80 }
81
82 /*
83  * Check that we have indeed attached to the thing..
84  */
85 int ptrace_check_attach(struct task_struct *child, int kill)
86 {
87         int ret = -ESRCH;
88
89         /*
90          * We take the read lock around doing both checks to close a
91          * possible race where someone else was tracing our child and
92          * detached between these two checks.  After this locked check,
93          * we are sure that this is our traced child and that can only
94          * be changed by us so it's not changing right after this.
95          */
96         read_lock(&tasklist_lock);
97         if ((child->ptrace & PT_PTRACED) && child->parent == current) {
98                 ret = 0;
99                 /*
100                  * child->sighand can't be NULL, release_task()
101                  * does ptrace_unlink() before __exit_signal().
102                  */
103                 spin_lock_irq(&child->sighand->siglock);
104                 if (task_is_stopped(child))
105                         child->state = TASK_TRACED;
106                 else if (!task_is_traced(child) && !kill)
107                         ret = -ESRCH;
108                 spin_unlock_irq(&child->sighand->siglock);
109         }
110         read_unlock(&tasklist_lock);
111
112         if (!ret && !kill)
113                 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
114
115         /* All systems go.. */
116         return ret;
117 }
118
119 int __ptrace_may_access(struct task_struct *task, unsigned int mode)
120 {
121         const struct cred *cred = current_cred(), *tcred;
122
123         /* May we inspect the given task?
124          * This check is used both for attaching with ptrace
125          * and for allowing access to sensitive information in /proc.
126          *
127          * ptrace_attach denies several cases that /proc allows
128          * because setting up the necessary parent/child relationship
129          * or halting the specified task is impossible.
130          */
131         int dumpable = 0;
132         /* Don't let security modules deny introspection */
133         if (task == current)
134                 return 0;
135         rcu_read_lock();
136         tcred = __task_cred(task);
137         if (cred->user->user_ns == tcred->user->user_ns &&
138             (cred->uid == tcred->euid &&
139              cred->uid == tcred->suid &&
140              cred->uid == tcred->uid  &&
141              cred->gid == tcred->egid &&
142              cred->gid == tcred->sgid &&
143              cred->gid == tcred->gid))
144                 goto ok;
145         if (ns_capable(tcred->user->user_ns, CAP_SYS_PTRACE))
146                 goto ok;
147         rcu_read_unlock();
148         return -EPERM;
149 ok:
150         rcu_read_unlock();
151         smp_rmb();
152         if (task->mm)
153                 dumpable = get_dumpable(task->mm);
154         if (!dumpable && !task_ns_capable(task, CAP_SYS_PTRACE))
155                 return -EPERM;
156
157         return security_ptrace_access_check(task, mode);
158 }
159
160 bool ptrace_may_access(struct task_struct *task, unsigned int mode)
161 {
162         int err;
163         task_lock(task);
164         err = __ptrace_may_access(task, mode);
165         task_unlock(task);
166         return !err;
167 }
168
169 static int ptrace_attach(struct task_struct *task)
170 {
171         int retval;
172
173         audit_ptrace(task);
174
175         retval = -EPERM;
176         if (unlikely(task->flags & PF_KTHREAD))
177                 goto out;
178         if (same_thread_group(task, current))
179                 goto out;
180
181         /*
182          * Protect exec's credential calculations against our interference;
183          * interference; SUID, SGID and LSM creds get determined differently
184          * under ptrace.
185          */
186         retval = -ERESTARTNOINTR;
187         if (mutex_lock_interruptible(&task->signal->cred_guard_mutex))
188                 goto out;
189
190         task_lock(task);
191         retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
192         task_unlock(task);
193         if (retval)
194                 goto unlock_creds;
195
196         write_lock_irq(&tasklist_lock);
197         retval = -EPERM;
198         if (unlikely(task->exit_state))
199                 goto unlock_tasklist;
200         if (task->ptrace)
201                 goto unlock_tasklist;
202
203         task->ptrace = PT_PTRACED;
204         if (task_ns_capable(task, CAP_SYS_PTRACE))
205                 task->ptrace |= PT_PTRACE_CAP;
206
207         __ptrace_link(task, current);
208         send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
209
210         retval = 0;
211 unlock_tasklist:
212         write_unlock_irq(&tasklist_lock);
213 unlock_creds:
214         mutex_unlock(&task->signal->cred_guard_mutex);
215 out:
216         return retval;
217 }
218
219 /**
220  * ptrace_traceme  --  helper for PTRACE_TRACEME
221  *
222  * Performs checks and sets PT_PTRACED.
223  * Should be used by all ptrace implementations for PTRACE_TRACEME.
224  */
225 static int ptrace_traceme(void)
226 {
227         int ret = -EPERM;
228
229         write_lock_irq(&tasklist_lock);
230         /* Are we already being traced? */
231         if (!current->ptrace) {
232                 ret = security_ptrace_traceme(current->parent);
233                 /*
234                  * Check PF_EXITING to ensure ->real_parent has not passed
235                  * exit_ptrace(). Otherwise we don't report the error but
236                  * pretend ->real_parent untraces us right after return.
237                  */
238                 if (!ret && !(current->real_parent->flags & PF_EXITING)) {
239                         current->ptrace = PT_PTRACED;
240                         __ptrace_link(current, current->real_parent);
241                 }
242         }
243         write_unlock_irq(&tasklist_lock);
244
245         return ret;
246 }
247
248 /*
249  * Called with irqs disabled, returns true if childs should reap themselves.
250  */
251 static int ignoring_children(struct sighand_struct *sigh)
252 {
253         int ret;
254         spin_lock(&sigh->siglock);
255         ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) ||
256               (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT);
257         spin_unlock(&sigh->siglock);
258         return ret;
259 }
260
261 /*
262  * Called with tasklist_lock held for writing.
263  * Unlink a traced task, and clean it up if it was a traced zombie.
264  * Return true if it needs to be reaped with release_task().
265  * (We can't call release_task() here because we already hold tasklist_lock.)
266  *
267  * If it's a zombie, our attachedness prevented normal parent notification
268  * or self-reaping.  Do notification now if it would have happened earlier.
269  * If it should reap itself, return true.
270  *
271  * If it's our own child, there is no notification to do. But if our normal
272  * children self-reap, then this child was prevented by ptrace and we must
273  * reap it now, in that case we must also wake up sub-threads sleeping in
274  * do_wait().
275  */
276 static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p)
277 {
278         __ptrace_unlink(p);
279
280         if (p->exit_state == EXIT_ZOMBIE) {
281                 if (!task_detached(p) && thread_group_empty(p)) {
282                         if (!same_thread_group(p->real_parent, tracer))
283                                 do_notify_parent(p, p->exit_signal);
284                         else if (ignoring_children(tracer->sighand)) {
285                                 __wake_up_parent(p, tracer);
286                                 p->exit_signal = -1;
287                         }
288                 }
289                 if (task_detached(p)) {
290                         /* Mark it as in the process of being reaped. */
291                         p->exit_state = EXIT_DEAD;
292                         return true;
293                 }
294         }
295
296         return false;
297 }
298
299 static int ptrace_detach(struct task_struct *child, unsigned int data)
300 {
301         bool dead = false;
302
303         if (!valid_signal(data))
304                 return -EIO;
305
306         /* Architecture-specific hardware disable .. */
307         ptrace_disable(child);
308         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
309
310         write_lock_irq(&tasklist_lock);
311         /*
312          * This child can be already killed. Make sure de_thread() or
313          * our sub-thread doing do_wait() didn't do release_task() yet.
314          */
315         if (child->ptrace) {
316                 child->exit_code = data;
317                 dead = __ptrace_detach(current, child);
318                 if (!child->exit_state)
319                         wake_up_state(child, TASK_TRACED | TASK_STOPPED);
320         }
321         write_unlock_irq(&tasklist_lock);
322
323         if (unlikely(dead))
324                 release_task(child);
325
326         return 0;
327 }
328
329 /*
330  * Detach all tasks we were using ptrace on. Called with tasklist held
331  * for writing, and returns with it held too. But note it can release
332  * and reacquire the lock.
333  */
334 void exit_ptrace(struct task_struct *tracer)
335         __releases(&tasklist_lock)
336         __acquires(&tasklist_lock)
337 {
338         struct task_struct *p, *n;
339         LIST_HEAD(ptrace_dead);
340
341         if (likely(list_empty(&tracer->ptraced)))
342                 return;
343
344         list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) {
345                 if (__ptrace_detach(tracer, p))
346                         list_add(&p->ptrace_entry, &ptrace_dead);
347         }
348
349         write_unlock_irq(&tasklist_lock);
350         BUG_ON(!list_empty(&tracer->ptraced));
351
352         list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) {
353                 list_del_init(&p->ptrace_entry);
354                 release_task(p);
355         }
356
357         write_lock_irq(&tasklist_lock);
358 }
359
360 int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
361 {
362         int copied = 0;
363
364         while (len > 0) {
365                 char buf[128];
366                 int this_len, retval;
367
368                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
369                 retval = access_process_vm(tsk, src, buf, this_len, 0);
370                 if (!retval) {
371                         if (copied)
372                                 break;
373                         return -EIO;
374                 }
375                 if (copy_to_user(dst, buf, retval))
376                         return -EFAULT;
377                 copied += retval;
378                 src += retval;
379                 dst += retval;
380                 len -= retval;
381         }
382         return copied;
383 }
384
385 int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
386 {
387         int copied = 0;
388
389         while (len > 0) {
390                 char buf[128];
391                 int this_len, retval;
392
393                 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
394                 if (copy_from_user(buf, src, this_len))
395                         return -EFAULT;
396                 retval = access_process_vm(tsk, dst, buf, this_len, 1);
397                 if (!retval) {
398                         if (copied)
399                                 break;
400                         return -EIO;
401                 }
402                 copied += retval;
403                 src += retval;
404                 dst += retval;
405                 len -= retval;
406         }
407         return copied;
408 }
409
410 static int ptrace_setoptions(struct task_struct *child, unsigned long data)
411 {
412         child->ptrace &= ~PT_TRACE_MASK;
413
414         if (data & PTRACE_O_TRACESYSGOOD)
415                 child->ptrace |= PT_TRACESYSGOOD;
416
417         if (data & PTRACE_O_TRACEFORK)
418                 child->ptrace |= PT_TRACE_FORK;
419
420         if (data & PTRACE_O_TRACEVFORK)
421                 child->ptrace |= PT_TRACE_VFORK;
422
423         if (data & PTRACE_O_TRACECLONE)
424                 child->ptrace |= PT_TRACE_CLONE;
425
426         if (data & PTRACE_O_TRACEEXEC)
427                 child->ptrace |= PT_TRACE_EXEC;
428
429         if (data & PTRACE_O_TRACEVFORKDONE)
430                 child->ptrace |= PT_TRACE_VFORK_DONE;
431
432         if (data & PTRACE_O_TRACEEXIT)
433                 child->ptrace |= PT_TRACE_EXIT;
434
435         return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
436 }
437
438 static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
439 {
440         unsigned long flags;
441         int error = -ESRCH;
442
443         if (lock_task_sighand(child, &flags)) {
444                 error = -EINVAL;
445                 if (likely(child->last_siginfo != NULL)) {
446                         *info = *child->last_siginfo;
447                         error = 0;
448                 }
449                 unlock_task_sighand(child, &flags);
450         }
451         return error;
452 }
453
454 static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
455 {
456         unsigned long flags;
457         int error = -ESRCH;
458
459         if (lock_task_sighand(child, &flags)) {
460                 error = -EINVAL;
461                 if (likely(child->last_siginfo != NULL)) {
462                         *child->last_siginfo = *info;
463                         error = 0;
464                 }
465                 unlock_task_sighand(child, &flags);
466         }
467         return error;
468 }
469
470
471 #ifdef PTRACE_SINGLESTEP
472 #define is_singlestep(request)          ((request) == PTRACE_SINGLESTEP)
473 #else
474 #define is_singlestep(request)          0
475 #endif
476
477 #ifdef PTRACE_SINGLEBLOCK
478 #define is_singleblock(request)         ((request) == PTRACE_SINGLEBLOCK)
479 #else
480 #define is_singleblock(request)         0
481 #endif
482
483 #ifdef PTRACE_SYSEMU
484 #define is_sysemu_singlestep(request)   ((request) == PTRACE_SYSEMU_SINGLESTEP)
485 #else
486 #define is_sysemu_singlestep(request)   0
487 #endif
488
489 static int ptrace_resume(struct task_struct *child, long request,
490                          unsigned long data)
491 {
492         if (!valid_signal(data))
493                 return -EIO;
494
495         if (request == PTRACE_SYSCALL)
496                 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
497         else
498                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
499
500 #ifdef TIF_SYSCALL_EMU
501         if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
502                 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
503         else
504                 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
505 #endif
506
507         if (is_singleblock(request)) {
508                 if (unlikely(!arch_has_block_step()))
509                         return -EIO;
510                 user_enable_block_step(child);
511         } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
512                 if (unlikely(!arch_has_single_step()))
513                         return -EIO;
514                 user_enable_single_step(child);
515         } else {
516                 user_disable_single_step(child);
517         }
518
519         child->exit_code = data;
520         wake_up_process(child);
521
522         return 0;
523 }
524
525 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
526
527 static const struct user_regset *
528 find_regset(const struct user_regset_view *view, unsigned int type)
529 {
530         const struct user_regset *regset;
531         int n;
532
533         for (n = 0; n < view->n; ++n) {
534                 regset = view->regsets + n;
535                 if (regset->core_note_type == type)
536                         return regset;
537         }
538
539         return NULL;
540 }
541
542 static int ptrace_regset(struct task_struct *task, int req, unsigned int type,
543                          struct iovec *kiov)
544 {
545         const struct user_regset_view *view = task_user_regset_view(task);
546         const struct user_regset *regset = find_regset(view, type);
547         int regset_no;
548
549         if (!regset || (kiov->iov_len % regset->size) != 0)
550                 return -EINVAL;
551
552         regset_no = regset - view->regsets;
553         kiov->iov_len = min(kiov->iov_len,
554                             (__kernel_size_t) (regset->n * regset->size));
555
556         if (req == PTRACE_GETREGSET)
557                 return copy_regset_to_user(task, view, regset_no, 0,
558                                            kiov->iov_len, kiov->iov_base);
559         else
560                 return copy_regset_from_user(task, view, regset_no, 0,
561                                              kiov->iov_len, kiov->iov_base);
562 }
563
564 #endif
565
566 int ptrace_request(struct task_struct *child, long request,
567                    unsigned long addr, unsigned long data)
568 {
569         int ret = -EIO;
570         siginfo_t siginfo;
571         void __user *datavp = (void __user *) data;
572         unsigned long __user *datalp = datavp;
573
574         switch (request) {
575         case PTRACE_PEEKTEXT:
576         case PTRACE_PEEKDATA:
577                 return generic_ptrace_peekdata(child, addr, data);
578         case PTRACE_POKETEXT:
579         case PTRACE_POKEDATA:
580                 return generic_ptrace_pokedata(child, addr, data);
581
582 #ifdef PTRACE_OLDSETOPTIONS
583         case PTRACE_OLDSETOPTIONS:
584 #endif
585         case PTRACE_SETOPTIONS:
586                 ret = ptrace_setoptions(child, data);
587                 break;
588         case PTRACE_GETEVENTMSG:
589                 ret = put_user(child->ptrace_message, datalp);
590                 break;
591
592         case PTRACE_GETSIGINFO:
593                 ret = ptrace_getsiginfo(child, &siginfo);
594                 if (!ret)
595                         ret = copy_siginfo_to_user(datavp, &siginfo);
596                 break;
597
598         case PTRACE_SETSIGINFO:
599                 if (copy_from_user(&siginfo, datavp, sizeof siginfo))
600                         ret = -EFAULT;
601                 else
602                         ret = ptrace_setsiginfo(child, &siginfo);
603                 break;
604
605         case PTRACE_DETACH:      /* detach a process that was attached. */
606                 ret = ptrace_detach(child, data);
607                 break;
608
609 #ifdef CONFIG_BINFMT_ELF_FDPIC
610         case PTRACE_GETFDPIC: {
611                 struct mm_struct *mm = get_task_mm(child);
612                 unsigned long tmp = 0;
613
614                 ret = -ESRCH;
615                 if (!mm)
616                         break;
617
618                 switch (addr) {
619                 case PTRACE_GETFDPIC_EXEC:
620                         tmp = mm->context.exec_fdpic_loadmap;
621                         break;
622                 case PTRACE_GETFDPIC_INTERP:
623                         tmp = mm->context.interp_fdpic_loadmap;
624                         break;
625                 default:
626                         break;
627                 }
628                 mmput(mm);
629
630                 ret = put_user(tmp, datalp);
631                 break;
632         }
633 #endif
634
635 #ifdef PTRACE_SINGLESTEP
636         case PTRACE_SINGLESTEP:
637 #endif
638 #ifdef PTRACE_SINGLEBLOCK
639         case PTRACE_SINGLEBLOCK:
640 #endif
641 #ifdef PTRACE_SYSEMU
642         case PTRACE_SYSEMU:
643         case PTRACE_SYSEMU_SINGLESTEP:
644 #endif
645         case PTRACE_SYSCALL:
646         case PTRACE_CONT:
647                 return ptrace_resume(child, request, data);
648
649         case PTRACE_KILL:
650                 if (child->exit_state)  /* already dead */
651                         return 0;
652                 return ptrace_resume(child, request, SIGKILL);
653
654 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
655         case PTRACE_GETREGSET:
656         case PTRACE_SETREGSET:
657         {
658                 struct iovec kiov;
659                 struct iovec __user *uiov = datavp;
660
661                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
662                         return -EFAULT;
663
664                 if (__get_user(kiov.iov_base, &uiov->iov_base) ||
665                     __get_user(kiov.iov_len, &uiov->iov_len))
666                         return -EFAULT;
667
668                 ret = ptrace_regset(child, request, addr, &kiov);
669                 if (!ret)
670                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
671                 break;
672         }
673 #endif
674         default:
675                 break;
676         }
677
678         return ret;
679 }
680
681 static struct task_struct *ptrace_get_task_struct(pid_t pid)
682 {
683         struct task_struct *child;
684
685         rcu_read_lock();
686         child = find_task_by_vpid(pid);
687         if (child)
688                 get_task_struct(child);
689         rcu_read_unlock();
690
691         if (!child)
692                 return ERR_PTR(-ESRCH);
693         return child;
694 }
695
696 #ifndef arch_ptrace_attach
697 #define arch_ptrace_attach(child)       do { } while (0)
698 #endif
699
700 SYSCALL_DEFINE4(ptrace, long, request, long, pid, unsigned long, addr,
701                 unsigned long, data)
702 {
703         struct task_struct *child;
704         long ret;
705
706         if (request == PTRACE_TRACEME) {
707                 ret = ptrace_traceme();
708                 if (!ret)
709                         arch_ptrace_attach(current);
710                 goto out;
711         }
712
713         child = ptrace_get_task_struct(pid);
714         if (IS_ERR(child)) {
715                 ret = PTR_ERR(child);
716                 goto out;
717         }
718
719         if (request == PTRACE_ATTACH) {
720                 ret = ptrace_attach(child);
721                 /*
722                  * Some architectures need to do book-keeping after
723                  * a ptrace attach.
724                  */
725                 if (!ret)
726                         arch_ptrace_attach(child);
727                 goto out_put_task_struct;
728         }
729
730         ret = ptrace_check_attach(child, request == PTRACE_KILL);
731         if (ret < 0)
732                 goto out_put_task_struct;
733
734         ret = arch_ptrace(child, request, addr, data);
735
736  out_put_task_struct:
737         put_task_struct(child);
738  out:
739         return ret;
740 }
741
742 int generic_ptrace_peekdata(struct task_struct *tsk, unsigned long addr,
743                             unsigned long data)
744 {
745         unsigned long tmp;
746         int copied;
747
748         copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
749         if (copied != sizeof(tmp))
750                 return -EIO;
751         return put_user(tmp, (unsigned long __user *)data);
752 }
753
754 int generic_ptrace_pokedata(struct task_struct *tsk, unsigned long addr,
755                             unsigned long data)
756 {
757         int copied;
758
759         copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
760         return (copied == sizeof(data)) ? 0 : -EIO;
761 }
762
763 #if defined CONFIG_COMPAT
764 #include <linux/compat.h>
765
766 int compat_ptrace_request(struct task_struct *child, compat_long_t request,
767                           compat_ulong_t addr, compat_ulong_t data)
768 {
769         compat_ulong_t __user *datap = compat_ptr(data);
770         compat_ulong_t word;
771         siginfo_t siginfo;
772         int ret;
773
774         switch (request) {
775         case PTRACE_PEEKTEXT:
776         case PTRACE_PEEKDATA:
777                 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
778                 if (ret != sizeof(word))
779                         ret = -EIO;
780                 else
781                         ret = put_user(word, datap);
782                 break;
783
784         case PTRACE_POKETEXT:
785         case PTRACE_POKEDATA:
786                 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
787                 ret = (ret != sizeof(data) ? -EIO : 0);
788                 break;
789
790         case PTRACE_GETEVENTMSG:
791                 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
792                 break;
793
794         case PTRACE_GETSIGINFO:
795                 ret = ptrace_getsiginfo(child, &siginfo);
796                 if (!ret)
797                         ret = copy_siginfo_to_user32(
798                                 (struct compat_siginfo __user *) datap,
799                                 &siginfo);
800                 break;
801
802         case PTRACE_SETSIGINFO:
803                 memset(&siginfo, 0, sizeof siginfo);
804                 if (copy_siginfo_from_user32(
805                             &siginfo, (struct compat_siginfo __user *) datap))
806                         ret = -EFAULT;
807                 else
808                         ret = ptrace_setsiginfo(child, &siginfo);
809                 break;
810 #ifdef CONFIG_HAVE_ARCH_TRACEHOOK
811         case PTRACE_GETREGSET:
812         case PTRACE_SETREGSET:
813         {
814                 struct iovec kiov;
815                 struct compat_iovec __user *uiov =
816                         (struct compat_iovec __user *) datap;
817                 compat_uptr_t ptr;
818                 compat_size_t len;
819
820                 if (!access_ok(VERIFY_WRITE, uiov, sizeof(*uiov)))
821                         return -EFAULT;
822
823                 if (__get_user(ptr, &uiov->iov_base) ||
824                     __get_user(len, &uiov->iov_len))
825                         return -EFAULT;
826
827                 kiov.iov_base = compat_ptr(ptr);
828                 kiov.iov_len = len;
829
830                 ret = ptrace_regset(child, request, addr, &kiov);
831                 if (!ret)
832                         ret = __put_user(kiov.iov_len, &uiov->iov_len);
833                 break;
834         }
835 #endif
836
837         default:
838                 ret = ptrace_request(child, request, addr, data);
839         }
840
841         return ret;
842 }
843
844 asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
845                                   compat_long_t addr, compat_long_t data)
846 {
847         struct task_struct *child;
848         long ret;
849
850         if (request == PTRACE_TRACEME) {
851                 ret = ptrace_traceme();
852                 goto out;
853         }
854
855         child = ptrace_get_task_struct(pid);
856         if (IS_ERR(child)) {
857                 ret = PTR_ERR(child);
858                 goto out;
859         }
860
861         if (request == PTRACE_ATTACH) {
862                 ret = ptrace_attach(child);
863                 /*
864                  * Some architectures need to do book-keeping after
865                  * a ptrace attach.
866                  */
867                 if (!ret)
868                         arch_ptrace_attach(child);
869                 goto out_put_task_struct;
870         }
871
872         ret = ptrace_check_attach(child, request == PTRACE_KILL);
873         if (!ret)
874                 ret = compat_arch_ptrace(child, request, addr, data);
875
876  out_put_task_struct:
877         put_task_struct(child);
878  out:
879         return ret;
880 }
881 #endif  /* CONFIG_COMPAT */