Commit | Line | Data |
---|---|---|
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> |
1da177e4 LT |
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/smp_lock.h> | |
18 | #include <linux/ptrace.h> | |
19 | #include <linux/security.h> | |
7ed20e1a | 20 | #include <linux/signal.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> |
1da177e4 | 25 | |
bf53de90 MM |
26 | |
27 | /* | |
28 | * Initialize a new task whose father had been ptraced. | |
29 | * | |
30 | * Called from copy_process(). | |
31 | */ | |
32 | void ptrace_fork(struct task_struct *child, unsigned long clone_flags) | |
33 | { | |
34 | arch_ptrace_fork(child, clone_flags); | |
35 | } | |
36 | ||
1da177e4 LT |
37 | /* |
38 | * ptrace a task: make the debugger its new parent and | |
39 | * move it to the ptrace list. | |
40 | * | |
41 | * Must be called with the tasklist lock write-held. | |
42 | */ | |
36c8b586 | 43 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) |
1da177e4 | 44 | { |
f470021a RM |
45 | BUG_ON(!list_empty(&child->ptrace_entry)); |
46 | list_add(&child->ptrace_entry, &new_parent->ptraced); | |
1da177e4 | 47 | child->parent = new_parent; |
1da177e4 | 48 | } |
3a709703 | 49 | |
1da177e4 LT |
50 | /* |
51 | * Turn a tracing stop into a normal stop now, since with no tracer there | |
52 | * would be no way to wake it up with SIGCONT or SIGKILL. If there was a | |
53 | * signal sent that would resume the child, but didn't because it was in | |
54 | * TASK_TRACED, resume it now. | |
55 | * Requires that irqs be disabled. | |
56 | */ | |
b747c8c1 | 57 | static void ptrace_untrace(struct task_struct *child) |
1da177e4 LT |
58 | { |
59 | spin_lock(&child->sighand->siglock); | |
6618a3e2 | 60 | if (task_is_traced(child)) { |
1ee11844 ON |
61 | /* |
62 | * If the group stop is completed or in progress, | |
63 | * this thread was already counted as stopped. | |
64 | */ | |
65 | if (child->signal->flags & SIGNAL_STOP_STOPPED || | |
66 | child->signal->group_stop_count) | |
d9ae90ac | 67 | __set_task_state(child, TASK_STOPPED); |
1ee11844 | 68 | else |
1da177e4 | 69 | signal_wake_up(child, 1); |
1da177e4 LT |
70 | } |
71 | spin_unlock(&child->sighand->siglock); | |
72 | } | |
73 | ||
74 | /* | |
75 | * unptrace a task: move it back to its original parent and | |
76 | * remove it from the ptrace list. | |
77 | * | |
78 | * Must be called with the tasklist lock write-held. | |
79 | */ | |
36c8b586 | 80 | void __ptrace_unlink(struct task_struct *child) |
1da177e4 | 81 | { |
5ecfbae0 ON |
82 | BUG_ON(!child->ptrace); |
83 | ||
1da177e4 | 84 | child->ptrace = 0; |
f470021a RM |
85 | child->parent = child->real_parent; |
86 | list_del_init(&child->ptrace_entry); | |
1da177e4 | 87 | |
bf53de90 | 88 | arch_ptrace_untrace(child); |
6618a3e2 | 89 | if (task_is_traced(child)) |
e57a5059 | 90 | ptrace_untrace(child); |
1da177e4 LT |
91 | } |
92 | ||
93 | /* | |
94 | * Check that we have indeed attached to the thing.. | |
95 | */ | |
96 | int ptrace_check_attach(struct task_struct *child, int kill) | |
97 | { | |
98 | int ret = -ESRCH; | |
99 | ||
100 | /* | |
101 | * We take the read lock around doing both checks to close a | |
102 | * possible race where someone else was tracing our child and | |
103 | * detached between these two checks. After this locked check, | |
104 | * we are sure that this is our traced child and that can only | |
105 | * be changed by us so it's not changing right after this. | |
106 | */ | |
107 | read_lock(&tasklist_lock); | |
c0c0b649 | 108 | if ((child->ptrace & PT_PTRACED) && child->parent == current) { |
1da177e4 | 109 | ret = 0; |
c0c0b649 ON |
110 | /* |
111 | * child->sighand can't be NULL, release_task() | |
112 | * does ptrace_unlink() before __exit_signal(). | |
113 | */ | |
1da177e4 | 114 | spin_lock_irq(&child->sighand->siglock); |
d9ae90ac | 115 | if (task_is_stopped(child)) |
1da177e4 | 116 | child->state = TASK_TRACED; |
d9ae90ac | 117 | else if (!task_is_traced(child) && !kill) |
1da177e4 | 118 | ret = -ESRCH; |
1da177e4 LT |
119 | spin_unlock_irq(&child->sighand->siglock); |
120 | } | |
121 | read_unlock(&tasklist_lock); | |
122 | ||
d9ae90ac | 123 | if (!ret && !kill) |
85ba2d86 | 124 | ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; |
1da177e4 LT |
125 | |
126 | /* All systems go.. */ | |
127 | return ret; | |
128 | } | |
129 | ||
006ebb40 | 130 | int __ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be | 131 | { |
c69e8d9c | 132 | const struct cred *cred = current_cred(), *tcred; |
b6dff3ec | 133 | |
df26c40e EB |
134 | /* May we inspect the given task? |
135 | * This check is used both for attaching with ptrace | |
136 | * and for allowing access to sensitive information in /proc. | |
137 | * | |
138 | * ptrace_attach denies several cases that /proc allows | |
139 | * because setting up the necessary parent/child relationship | |
140 | * or halting the specified task is impossible. | |
141 | */ | |
142 | int dumpable = 0; | |
143 | /* Don't let security modules deny introspection */ | |
144 | if (task == current) | |
145 | return 0; | |
c69e8d9c DH |
146 | rcu_read_lock(); |
147 | tcred = __task_cred(task); | |
148 | if ((cred->uid != tcred->euid || | |
149 | cred->uid != tcred->suid || | |
150 | cred->uid != tcred->uid || | |
151 | cred->gid != tcred->egid || | |
152 | cred->gid != tcred->sgid || | |
153 | cred->gid != tcred->gid) && | |
154 | !capable(CAP_SYS_PTRACE)) { | |
155 | rcu_read_unlock(); | |
ab8d11be | 156 | return -EPERM; |
c69e8d9c DH |
157 | } |
158 | rcu_read_unlock(); | |
ab8d11be | 159 | smp_rmb(); |
df26c40e | 160 | if (task->mm) |
6c5d5238 | 161 | dumpable = get_dumpable(task->mm); |
df26c40e | 162 | if (!dumpable && !capable(CAP_SYS_PTRACE)) |
ab8d11be MS |
163 | return -EPERM; |
164 | ||
5cd9c58f | 165 | return security_ptrace_may_access(task, mode); |
ab8d11be MS |
166 | } |
167 | ||
006ebb40 | 168 | bool ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be MS |
169 | { |
170 | int err; | |
171 | task_lock(task); | |
006ebb40 | 172 | err = __ptrace_may_access(task, mode); |
ab8d11be | 173 | task_unlock(task); |
3a709703 | 174 | return !err; |
ab8d11be MS |
175 | } |
176 | ||
1da177e4 LT |
177 | int ptrace_attach(struct task_struct *task) |
178 | { | |
179 | int retval; | |
6175ecfe | 180 | unsigned long flags; |
f5b40e36 | 181 | |
a5cb013d AV |
182 | audit_ptrace(task); |
183 | ||
1da177e4 | 184 | retval = -EPERM; |
bac0abd6 | 185 | if (same_thread_group(task, current)) |
f5b40e36 LT |
186 | goto out; |
187 | ||
d84f4f99 DH |
188 | /* Protect exec's credential calculations against our interference; |
189 | * SUID, SGID and LSM creds get determined differently under ptrace. | |
190 | */ | |
cad81bc2 | 191 | retval = mutex_lock_interruptible(&task->cred_exec_mutex); |
d84f4f99 DH |
192 | if (retval < 0) |
193 | goto out; | |
194 | ||
195 | retval = -EPERM; | |
f358166a LT |
196 | repeat: |
197 | /* | |
198 | * Nasty, nasty. | |
199 | * | |
200 | * We want to hold both the task-lock and the | |
201 | * tasklist_lock for writing at the same time. | |
202 | * But that's against the rules (tasklist_lock | |
203 | * is taken for reading by interrupts on other | |
204 | * cpu's that may have task_lock). | |
205 | */ | |
f5b40e36 | 206 | task_lock(task); |
6175ecfe | 207 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { |
f358166a LT |
208 | task_unlock(task); |
209 | do { | |
210 | cpu_relax(); | |
211 | } while (!write_can_lock(&tasklist_lock)); | |
212 | goto repeat; | |
213 | } | |
f5b40e36 | 214 | |
df26c40e EB |
215 | if (!task->mm) |
216 | goto bad; | |
1da177e4 LT |
217 | /* the same process cannot be attached many times */ |
218 | if (task->ptrace & PT_PTRACED) | |
219 | goto bad; | |
006ebb40 | 220 | retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); |
1da177e4 LT |
221 | if (retval) |
222 | goto bad; | |
223 | ||
224 | /* Go */ | |
6b39c7bf | 225 | task->ptrace |= PT_PTRACED; |
1da177e4 LT |
226 | if (capable(CAP_SYS_PTRACE)) |
227 | task->ptrace |= PT_PTRACE_CAP; | |
1da177e4 | 228 | |
1da177e4 | 229 | __ptrace_link(task, current); |
1da177e4 | 230 | |
33e9fc7d | 231 | send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); |
1da177e4 | 232 | bad: |
6175ecfe | 233 | write_unlock_irqrestore(&tasklist_lock, flags); |
1da177e4 | 234 | task_unlock(task); |
cad81bc2 | 235 | mutex_unlock(&task->cred_exec_mutex); |
f5b40e36 | 236 | out: |
1da177e4 LT |
237 | return retval; |
238 | } | |
239 | ||
39c626ae ON |
240 | /* |
241 | * Called with irqs disabled, returns true if childs should reap themselves. | |
242 | */ | |
243 | static int ignoring_children(struct sighand_struct *sigh) | |
244 | { | |
245 | int ret; | |
246 | spin_lock(&sigh->siglock); | |
247 | ret = (sigh->action[SIGCHLD-1].sa.sa_handler == SIG_IGN) || | |
248 | (sigh->action[SIGCHLD-1].sa.sa_flags & SA_NOCLDWAIT); | |
249 | spin_unlock(&sigh->siglock); | |
250 | return ret; | |
251 | } | |
252 | ||
253 | /* | |
254 | * Called with tasklist_lock held for writing. | |
255 | * Unlink a traced task, and clean it up if it was a traced zombie. | |
256 | * Return true if it needs to be reaped with release_task(). | |
257 | * (We can't call release_task() here because we already hold tasklist_lock.) | |
258 | * | |
259 | * If it's a zombie, our attachedness prevented normal parent notification | |
260 | * or self-reaping. Do notification now if it would have happened earlier. | |
261 | * If it should reap itself, return true. | |
262 | * | |
263 | * If it's our own child, there is no notification to do. | |
264 | * But if our normal children self-reap, then this child | |
265 | * was prevented by ptrace and we must reap it now. | |
266 | */ | |
267 | static bool __ptrace_detach(struct task_struct *tracer, struct task_struct *p) | |
268 | { | |
269 | __ptrace_unlink(p); | |
270 | ||
271 | if (p->exit_state == EXIT_ZOMBIE) { | |
272 | if (!task_detached(p) && thread_group_empty(p)) { | |
273 | if (!same_thread_group(p->real_parent, tracer)) | |
274 | do_notify_parent(p, p->exit_signal); | |
275 | else if (ignoring_children(tracer->sighand)) | |
276 | p->exit_signal = -1; | |
277 | } | |
278 | if (task_detached(p)) { | |
279 | /* Mark it as in the process of being reaped. */ | |
280 | p->exit_state = EXIT_DEAD; | |
281 | return true; | |
282 | } | |
283 | } | |
284 | ||
285 | return false; | |
286 | } | |
287 | ||
1da177e4 LT |
288 | int ptrace_detach(struct task_struct *child, unsigned int data) |
289 | { | |
39c626ae | 290 | bool dead = false; |
4576145c | 291 | |
7ed20e1a | 292 | if (!valid_signal(data)) |
5ecfbae0 | 293 | return -EIO; |
1da177e4 LT |
294 | |
295 | /* Architecture-specific hardware disable .. */ | |
296 | ptrace_disable(child); | |
7d941432 | 297 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
1da177e4 | 298 | |
95c3eb76 | 299 | write_lock_irq(&tasklist_lock); |
39c626ae ON |
300 | /* |
301 | * This child can be already killed. Make sure de_thread() or | |
302 | * our sub-thread doing do_wait() didn't do release_task() yet. | |
303 | */ | |
95c3eb76 ON |
304 | if (child->ptrace) { |
305 | child->exit_code = data; | |
4576145c | 306 | dead = __ptrace_detach(current, child); |
95c3eb76 | 307 | } |
1da177e4 LT |
308 | write_unlock_irq(&tasklist_lock); |
309 | ||
4576145c ON |
310 | if (unlikely(dead)) |
311 | release_task(child); | |
312 | ||
1da177e4 LT |
313 | return 0; |
314 | } | |
315 | ||
39c626ae ON |
316 | /* |
317 | * Detach all tasks we were using ptrace on. | |
318 | */ | |
319 | void exit_ptrace(struct task_struct *tracer) | |
320 | { | |
321 | struct task_struct *p, *n; | |
322 | LIST_HEAD(ptrace_dead); | |
323 | ||
324 | write_lock_irq(&tasklist_lock); | |
325 | list_for_each_entry_safe(p, n, &tracer->ptraced, ptrace_entry) { | |
326 | if (__ptrace_detach(tracer, p)) | |
327 | list_add(&p->ptrace_entry, &ptrace_dead); | |
328 | } | |
329 | write_unlock_irq(&tasklist_lock); | |
330 | ||
331 | BUG_ON(!list_empty(&tracer->ptraced)); | |
332 | ||
333 | list_for_each_entry_safe(p, n, &ptrace_dead, ptrace_entry) { | |
334 | list_del_init(&p->ptrace_entry); | |
335 | release_task(p); | |
336 | } | |
337 | } | |
338 | ||
1da177e4 LT |
339 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) |
340 | { | |
341 | int copied = 0; | |
342 | ||
343 | while (len > 0) { | |
344 | char buf[128]; | |
345 | int this_len, retval; | |
346 | ||
347 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
348 | retval = access_process_vm(tsk, src, buf, this_len, 0); | |
349 | if (!retval) { | |
350 | if (copied) | |
351 | break; | |
352 | return -EIO; | |
353 | } | |
354 | if (copy_to_user(dst, buf, retval)) | |
355 | return -EFAULT; | |
356 | copied += retval; | |
357 | src += retval; | |
358 | dst += retval; | |
3a709703 | 359 | len -= retval; |
1da177e4 LT |
360 | } |
361 | return copied; | |
362 | } | |
363 | ||
364 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) | |
365 | { | |
366 | int copied = 0; | |
367 | ||
368 | while (len > 0) { | |
369 | char buf[128]; | |
370 | int this_len, retval; | |
371 | ||
372 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
373 | if (copy_from_user(buf, src, this_len)) | |
374 | return -EFAULT; | |
375 | retval = access_process_vm(tsk, dst, buf, this_len, 1); | |
376 | if (!retval) { | |
377 | if (copied) | |
378 | break; | |
379 | return -EIO; | |
380 | } | |
381 | copied += retval; | |
382 | src += retval; | |
383 | dst += retval; | |
3a709703 | 384 | len -= retval; |
1da177e4 LT |
385 | } |
386 | return copied; | |
387 | } | |
388 | ||
389 | static int ptrace_setoptions(struct task_struct *child, long data) | |
390 | { | |
391 | child->ptrace &= ~PT_TRACE_MASK; | |
392 | ||
393 | if (data & PTRACE_O_TRACESYSGOOD) | |
394 | child->ptrace |= PT_TRACESYSGOOD; | |
395 | ||
396 | if (data & PTRACE_O_TRACEFORK) | |
397 | child->ptrace |= PT_TRACE_FORK; | |
398 | ||
399 | if (data & PTRACE_O_TRACEVFORK) | |
400 | child->ptrace |= PT_TRACE_VFORK; | |
401 | ||
402 | if (data & PTRACE_O_TRACECLONE) | |
403 | child->ptrace |= PT_TRACE_CLONE; | |
404 | ||
405 | if (data & PTRACE_O_TRACEEXEC) | |
406 | child->ptrace |= PT_TRACE_EXEC; | |
407 | ||
408 | if (data & PTRACE_O_TRACEVFORKDONE) | |
409 | child->ptrace |= PT_TRACE_VFORK_DONE; | |
410 | ||
411 | if (data & PTRACE_O_TRACEEXIT) | |
412 | child->ptrace |= PT_TRACE_EXIT; | |
413 | ||
414 | return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; | |
415 | } | |
416 | ||
e16b2781 | 417 | static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) |
1da177e4 | 418 | { |
1da177e4 LT |
419 | int error = -ESRCH; |
420 | ||
421 | read_lock(&tasklist_lock); | |
422 | if (likely(child->sighand != NULL)) { | |
423 | error = -EINVAL; | |
424 | spin_lock_irq(&child->sighand->siglock); | |
425 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 426 | *info = *child->last_siginfo; |
1da177e4 LT |
427 | error = 0; |
428 | } | |
429 | spin_unlock_irq(&child->sighand->siglock); | |
430 | } | |
431 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
432 | return error; |
433 | } | |
434 | ||
e16b2781 | 435 | static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) |
1da177e4 | 436 | { |
1da177e4 LT |
437 | int error = -ESRCH; |
438 | ||
1da177e4 LT |
439 | read_lock(&tasklist_lock); |
440 | if (likely(child->sighand != NULL)) { | |
441 | error = -EINVAL; | |
442 | spin_lock_irq(&child->sighand->siglock); | |
443 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 444 | *child->last_siginfo = *info; |
1da177e4 LT |
445 | error = 0; |
446 | } | |
447 | spin_unlock_irq(&child->sighand->siglock); | |
448 | } | |
449 | read_unlock(&tasklist_lock); | |
450 | return error; | |
451 | } | |
452 | ||
36df29d7 RM |
453 | |
454 | #ifdef PTRACE_SINGLESTEP | |
455 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) | |
456 | #else | |
457 | #define is_singlestep(request) 0 | |
458 | #endif | |
459 | ||
5b88abbf RM |
460 | #ifdef PTRACE_SINGLEBLOCK |
461 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) | |
462 | #else | |
463 | #define is_singleblock(request) 0 | |
464 | #endif | |
465 | ||
36df29d7 RM |
466 | #ifdef PTRACE_SYSEMU |
467 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) | |
468 | #else | |
469 | #define is_sysemu_singlestep(request) 0 | |
470 | #endif | |
471 | ||
472 | static int ptrace_resume(struct task_struct *child, long request, long data) | |
473 | { | |
474 | if (!valid_signal(data)) | |
475 | return -EIO; | |
476 | ||
477 | if (request == PTRACE_SYSCALL) | |
478 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
479 | else | |
480 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
481 | ||
482 | #ifdef TIF_SYSCALL_EMU | |
483 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) | |
484 | set_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
485 | else | |
486 | clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
487 | #endif | |
488 | ||
5b88abbf RM |
489 | if (is_singleblock(request)) { |
490 | if (unlikely(!arch_has_block_step())) | |
491 | return -EIO; | |
492 | user_enable_block_step(child); | |
493 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { | |
36df29d7 RM |
494 | if (unlikely(!arch_has_single_step())) |
495 | return -EIO; | |
496 | user_enable_single_step(child); | |
3a709703 | 497 | } else { |
36df29d7 | 498 | user_disable_single_step(child); |
3a709703 | 499 | } |
36df29d7 RM |
500 | |
501 | child->exit_code = data; | |
502 | wake_up_process(child); | |
503 | ||
504 | return 0; | |
505 | } | |
506 | ||
1da177e4 LT |
507 | int ptrace_request(struct task_struct *child, long request, |
508 | long addr, long data) | |
509 | { | |
510 | int ret = -EIO; | |
e16b2781 | 511 | siginfo_t siginfo; |
1da177e4 LT |
512 | |
513 | switch (request) { | |
16c3e389 RM |
514 | case PTRACE_PEEKTEXT: |
515 | case PTRACE_PEEKDATA: | |
516 | return generic_ptrace_peekdata(child, addr, data); | |
517 | case PTRACE_POKETEXT: | |
518 | case PTRACE_POKEDATA: | |
519 | return generic_ptrace_pokedata(child, addr, data); | |
520 | ||
1da177e4 LT |
521 | #ifdef PTRACE_OLDSETOPTIONS |
522 | case PTRACE_OLDSETOPTIONS: | |
523 | #endif | |
524 | case PTRACE_SETOPTIONS: | |
525 | ret = ptrace_setoptions(child, data); | |
526 | break; | |
527 | case PTRACE_GETEVENTMSG: | |
528 | ret = put_user(child->ptrace_message, (unsigned long __user *) data); | |
529 | break; | |
e16b2781 | 530 | |
1da177e4 | 531 | case PTRACE_GETSIGINFO: |
e16b2781 RM |
532 | ret = ptrace_getsiginfo(child, &siginfo); |
533 | if (!ret) | |
534 | ret = copy_siginfo_to_user((siginfo_t __user *) data, | |
535 | &siginfo); | |
1da177e4 | 536 | break; |
e16b2781 | 537 | |
1da177e4 | 538 | case PTRACE_SETSIGINFO: |
e16b2781 RM |
539 | if (copy_from_user(&siginfo, (siginfo_t __user *) data, |
540 | sizeof siginfo)) | |
541 | ret = -EFAULT; | |
542 | else | |
543 | ret = ptrace_setsiginfo(child, &siginfo); | |
1da177e4 | 544 | break; |
e16b2781 | 545 | |
1bcf5482 AD |
546 | case PTRACE_DETACH: /* detach a process that was attached. */ |
547 | ret = ptrace_detach(child, data); | |
548 | break; | |
36df29d7 RM |
549 | |
550 | #ifdef PTRACE_SINGLESTEP | |
551 | case PTRACE_SINGLESTEP: | |
552 | #endif | |
5b88abbf RM |
553 | #ifdef PTRACE_SINGLEBLOCK |
554 | case PTRACE_SINGLEBLOCK: | |
555 | #endif | |
36df29d7 RM |
556 | #ifdef PTRACE_SYSEMU |
557 | case PTRACE_SYSEMU: | |
558 | case PTRACE_SYSEMU_SINGLESTEP: | |
559 | #endif | |
560 | case PTRACE_SYSCALL: | |
561 | case PTRACE_CONT: | |
562 | return ptrace_resume(child, request, data); | |
563 | ||
564 | case PTRACE_KILL: | |
565 | if (child->exit_state) /* already dead */ | |
566 | return 0; | |
567 | return ptrace_resume(child, request, SIGKILL); | |
568 | ||
1da177e4 LT |
569 | default: |
570 | break; | |
571 | } | |
572 | ||
573 | return ret; | |
574 | } | |
481bed45 | 575 | |
6b9c7ed8 CH |
576 | /** |
577 | * ptrace_traceme -- helper for PTRACE_TRACEME | |
578 | * | |
579 | * Performs checks and sets PT_PTRACED. | |
580 | * Should be used by all ptrace implementations for PTRACE_TRACEME. | |
581 | */ | |
582 | int ptrace_traceme(void) | |
481bed45 | 583 | { |
f5b40e36 | 584 | int ret = -EPERM; |
481bed45 CH |
585 | |
586 | /* | |
6b9c7ed8 CH |
587 | * Are we already being traced? |
588 | */ | |
f470021a | 589 | repeat: |
f5b40e36 LT |
590 | task_lock(current); |
591 | if (!(current->ptrace & PT_PTRACED)) { | |
f470021a RM |
592 | /* |
593 | * See ptrace_attach() comments about the locking here. | |
594 | */ | |
595 | unsigned long flags; | |
596 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { | |
597 | task_unlock(current); | |
598 | do { | |
599 | cpu_relax(); | |
600 | } while (!write_can_lock(&tasklist_lock)); | |
601 | goto repeat; | |
602 | } | |
603 | ||
5cd9c58f | 604 | ret = security_ptrace_traceme(current->parent); |
f470021a | 605 | |
f5b40e36 | 606 | /* |
f1671f6d ON |
607 | * Check PF_EXITING to ensure ->real_parent has not passed |
608 | * exit_ptrace(). Otherwise we don't report the error but | |
609 | * pretend ->real_parent untraces us right after return. | |
f5b40e36 | 610 | */ |
f1671f6d | 611 | if (!ret && !(current->real_parent->flags & PF_EXITING)) { |
f5b40e36 | 612 | current->ptrace |= PT_PTRACED; |
f470021a RM |
613 | __ptrace_link(current, current->real_parent); |
614 | } | |
615 | ||
616 | write_unlock_irqrestore(&tasklist_lock, flags); | |
f5b40e36 LT |
617 | } |
618 | task_unlock(current); | |
619 | return ret; | |
6b9c7ed8 | 620 | } |
481bed45 | 621 | |
6b9c7ed8 CH |
622 | /** |
623 | * ptrace_get_task_struct -- grab a task struct reference for ptrace | |
624 | * @pid: process id to grab a task_struct reference of | |
625 | * | |
626 | * This function is a helper for ptrace implementations. It checks | |
627 | * permissions and then grabs a task struct for use of the actual | |
628 | * ptrace implementation. | |
629 | * | |
630 | * Returns the task_struct for @pid or an ERR_PTR() on failure. | |
631 | */ | |
632 | struct task_struct *ptrace_get_task_struct(pid_t pid) | |
633 | { | |
634 | struct task_struct *child; | |
481bed45 | 635 | |
481bed45 | 636 | read_lock(&tasklist_lock); |
228ebcbe | 637 | child = find_task_by_vpid(pid); |
481bed45 CH |
638 | if (child) |
639 | get_task_struct(child); | |
f400e198 | 640 | |
481bed45 CH |
641 | read_unlock(&tasklist_lock); |
642 | if (!child) | |
6b9c7ed8 CH |
643 | return ERR_PTR(-ESRCH); |
644 | return child; | |
481bed45 CH |
645 | } |
646 | ||
0ac15559 CH |
647 | #ifndef arch_ptrace_attach |
648 | #define arch_ptrace_attach(child) do { } while (0) | |
649 | #endif | |
650 | ||
1e7bfb21 | 651 | SYSCALL_DEFINE4(ptrace, long, request, long, pid, long, addr, long, data) |
481bed45 CH |
652 | { |
653 | struct task_struct *child; | |
654 | long ret; | |
655 | ||
656 | /* | |
657 | * This lock_kernel fixes a subtle race with suid exec | |
658 | */ | |
659 | lock_kernel(); | |
6b9c7ed8 CH |
660 | if (request == PTRACE_TRACEME) { |
661 | ret = ptrace_traceme(); | |
6ea6dd93 HS |
662 | if (!ret) |
663 | arch_ptrace_attach(current); | |
481bed45 | 664 | goto out; |
6b9c7ed8 CH |
665 | } |
666 | ||
667 | child = ptrace_get_task_struct(pid); | |
668 | if (IS_ERR(child)) { | |
669 | ret = PTR_ERR(child); | |
670 | goto out; | |
671 | } | |
481bed45 CH |
672 | |
673 | if (request == PTRACE_ATTACH) { | |
674 | ret = ptrace_attach(child); | |
0ac15559 CH |
675 | /* |
676 | * Some architectures need to do book-keeping after | |
677 | * a ptrace attach. | |
678 | */ | |
679 | if (!ret) | |
680 | arch_ptrace_attach(child); | |
005f18df | 681 | goto out_put_task_struct; |
481bed45 CH |
682 | } |
683 | ||
684 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
685 | if (ret < 0) | |
686 | goto out_put_task_struct; | |
687 | ||
688 | ret = arch_ptrace(child, request, addr, data); | |
481bed45 CH |
689 | |
690 | out_put_task_struct: | |
691 | put_task_struct(child); | |
692 | out: | |
693 | unlock_kernel(); | |
694 | return ret; | |
695 | } | |
76647323 AD |
696 | |
697 | int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data) | |
698 | { | |
699 | unsigned long tmp; | |
700 | int copied; | |
701 | ||
702 | copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); | |
703 | if (copied != sizeof(tmp)) | |
704 | return -EIO; | |
705 | return put_user(tmp, (unsigned long __user *)data); | |
706 | } | |
f284ce72 AD |
707 | |
708 | int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data) | |
709 | { | |
710 | int copied; | |
711 | ||
712 | copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); | |
713 | return (copied == sizeof(data)) ? 0 : -EIO; | |
714 | } | |
032d82d9 | 715 | |
96b8936a | 716 | #if defined CONFIG_COMPAT |
032d82d9 RM |
717 | #include <linux/compat.h> |
718 | ||
719 | int compat_ptrace_request(struct task_struct *child, compat_long_t request, | |
720 | compat_ulong_t addr, compat_ulong_t data) | |
721 | { | |
722 | compat_ulong_t __user *datap = compat_ptr(data); | |
723 | compat_ulong_t word; | |
e16b2781 | 724 | siginfo_t siginfo; |
032d82d9 RM |
725 | int ret; |
726 | ||
727 | switch (request) { | |
728 | case PTRACE_PEEKTEXT: | |
729 | case PTRACE_PEEKDATA: | |
730 | ret = access_process_vm(child, addr, &word, sizeof(word), 0); | |
731 | if (ret != sizeof(word)) | |
732 | ret = -EIO; | |
733 | else | |
734 | ret = put_user(word, datap); | |
735 | break; | |
736 | ||
737 | case PTRACE_POKETEXT: | |
738 | case PTRACE_POKEDATA: | |
739 | ret = access_process_vm(child, addr, &data, sizeof(data), 1); | |
740 | ret = (ret != sizeof(data) ? -EIO : 0); | |
741 | break; | |
742 | ||
743 | case PTRACE_GETEVENTMSG: | |
744 | ret = put_user((compat_ulong_t) child->ptrace_message, datap); | |
745 | break; | |
746 | ||
e16b2781 RM |
747 | case PTRACE_GETSIGINFO: |
748 | ret = ptrace_getsiginfo(child, &siginfo); | |
749 | if (!ret) | |
750 | ret = copy_siginfo_to_user32( | |
751 | (struct compat_siginfo __user *) datap, | |
752 | &siginfo); | |
753 | break; | |
754 | ||
755 | case PTRACE_SETSIGINFO: | |
756 | memset(&siginfo, 0, sizeof siginfo); | |
757 | if (copy_siginfo_from_user32( | |
758 | &siginfo, (struct compat_siginfo __user *) datap)) | |
759 | ret = -EFAULT; | |
760 | else | |
761 | ret = ptrace_setsiginfo(child, &siginfo); | |
762 | break; | |
763 | ||
032d82d9 RM |
764 | default: |
765 | ret = ptrace_request(child, request, addr, data); | |
766 | } | |
767 | ||
768 | return ret; | |
769 | } | |
c269f196 | 770 | |
c269f196 RM |
771 | asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, |
772 | compat_long_t addr, compat_long_t data) | |
773 | { | |
774 | struct task_struct *child; | |
775 | long ret; | |
776 | ||
777 | /* | |
778 | * This lock_kernel fixes a subtle race with suid exec | |
779 | */ | |
780 | lock_kernel(); | |
781 | if (request == PTRACE_TRACEME) { | |
782 | ret = ptrace_traceme(); | |
783 | goto out; | |
784 | } | |
785 | ||
786 | child = ptrace_get_task_struct(pid); | |
787 | if (IS_ERR(child)) { | |
788 | ret = PTR_ERR(child); | |
789 | goto out; | |
790 | } | |
791 | ||
792 | if (request == PTRACE_ATTACH) { | |
793 | ret = ptrace_attach(child); | |
794 | /* | |
795 | * Some architectures need to do book-keeping after | |
796 | * a ptrace attach. | |
797 | */ | |
798 | if (!ret) | |
799 | arch_ptrace_attach(child); | |
800 | goto out_put_task_struct; | |
801 | } | |
802 | ||
803 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
804 | if (!ret) | |
805 | ret = compat_arch_ptrace(child, request, addr, data); | |
806 | ||
807 | out_put_task_struct: | |
808 | put_task_struct(child); | |
809 | out: | |
810 | unlock_kernel(); | |
811 | return ret; | |
812 | } | |
96b8936a | 813 | #endif /* CONFIG_COMPAT */ |