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

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