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Commit | Line | Data |
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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> |
1da177e4 LT |
24 | |
25 | #include <asm/pgtable.h> | |
26 | #include <asm/uaccess.h> | |
27 | ||
28 | /* | |
29 | * ptrace a task: make the debugger its new parent and | |
30 | * move it to the ptrace list. | |
31 | * | |
32 | * Must be called with the tasklist lock write-held. | |
33 | */ | |
36c8b586 | 34 | void __ptrace_link(struct task_struct *child, struct task_struct *new_parent) |
1da177e4 | 35 | { |
f470021a RM |
36 | BUG_ON(!list_empty(&child->ptrace_entry)); |
37 | list_add(&child->ptrace_entry, &new_parent->ptraced); | |
1da177e4 | 38 | child->parent = new_parent; |
1da177e4 LT |
39 | } |
40 | ||
41 | /* | |
42 | * Turn a tracing stop into a normal stop now, since with no tracer there | |
43 | * would be no way to wake it up with SIGCONT or SIGKILL. If there was a | |
44 | * signal sent that would resume the child, but didn't because it was in | |
45 | * TASK_TRACED, resume it now. | |
46 | * Requires that irqs be disabled. | |
47 | */ | |
b747c8c1 | 48 | static void ptrace_untrace(struct task_struct *child) |
1da177e4 LT |
49 | { |
50 | spin_lock(&child->sighand->siglock); | |
6618a3e2 | 51 | if (task_is_traced(child)) { |
1da177e4 | 52 | if (child->signal->flags & SIGNAL_STOP_STOPPED) { |
d9ae90ac | 53 | __set_task_state(child, TASK_STOPPED); |
1da177e4 LT |
54 | } else { |
55 | signal_wake_up(child, 1); | |
56 | } | |
57 | } | |
58 | spin_unlock(&child->sighand->siglock); | |
59 | } | |
60 | ||
61 | /* | |
62 | * unptrace a task: move it back to its original parent and | |
63 | * remove it from the ptrace list. | |
64 | * | |
65 | * Must be called with the tasklist lock write-held. | |
66 | */ | |
36c8b586 | 67 | void __ptrace_unlink(struct task_struct *child) |
1da177e4 | 68 | { |
5ecfbae0 ON |
69 | BUG_ON(!child->ptrace); |
70 | ||
1da177e4 | 71 | child->ptrace = 0; |
f470021a RM |
72 | child->parent = child->real_parent; |
73 | list_del_init(&child->ptrace_entry); | |
1da177e4 | 74 | |
6618a3e2 | 75 | if (task_is_traced(child)) |
e57a5059 | 76 | ptrace_untrace(child); |
1da177e4 LT |
77 | } |
78 | ||
79 | /* | |
80 | * Check that we have indeed attached to the thing.. | |
81 | */ | |
82 | int ptrace_check_attach(struct task_struct *child, int kill) | |
83 | { | |
84 | int ret = -ESRCH; | |
85 | ||
86 | /* | |
87 | * We take the read lock around doing both checks to close a | |
88 | * possible race where someone else was tracing our child and | |
89 | * detached between these two checks. After this locked check, | |
90 | * we are sure that this is our traced child and that can only | |
91 | * be changed by us so it's not changing right after this. | |
92 | */ | |
93 | read_lock(&tasklist_lock); | |
c0c0b649 | 94 | if ((child->ptrace & PT_PTRACED) && child->parent == current) { |
1da177e4 | 95 | ret = 0; |
c0c0b649 ON |
96 | /* |
97 | * child->sighand can't be NULL, release_task() | |
98 | * does ptrace_unlink() before __exit_signal(). | |
99 | */ | |
1da177e4 | 100 | spin_lock_irq(&child->sighand->siglock); |
d9ae90ac | 101 | if (task_is_stopped(child)) |
1da177e4 | 102 | child->state = TASK_TRACED; |
d9ae90ac | 103 | else if (!task_is_traced(child) && !kill) |
1da177e4 | 104 | ret = -ESRCH; |
1da177e4 LT |
105 | spin_unlock_irq(&child->sighand->siglock); |
106 | } | |
107 | read_unlock(&tasklist_lock); | |
108 | ||
d9ae90ac | 109 | if (!ret && !kill) |
85ba2d86 | 110 | ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH; |
1da177e4 LT |
111 | |
112 | /* All systems go.. */ | |
113 | return ret; | |
114 | } | |
115 | ||
006ebb40 | 116 | int __ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be | 117 | { |
c69e8d9c | 118 | const struct cred *cred = current_cred(), *tcred; |
b6dff3ec | 119 | |
df26c40e EB |
120 | /* May we inspect the given task? |
121 | * This check is used both for attaching with ptrace | |
122 | * and for allowing access to sensitive information in /proc. | |
123 | * | |
124 | * ptrace_attach denies several cases that /proc allows | |
125 | * because setting up the necessary parent/child relationship | |
126 | * or halting the specified task is impossible. | |
127 | */ | |
128 | int dumpable = 0; | |
129 | /* Don't let security modules deny introspection */ | |
130 | if (task == current) | |
131 | return 0; | |
c69e8d9c DH |
132 | rcu_read_lock(); |
133 | tcred = __task_cred(task); | |
134 | if ((cred->uid != tcred->euid || | |
135 | cred->uid != tcred->suid || | |
136 | cred->uid != tcred->uid || | |
137 | cred->gid != tcred->egid || | |
138 | cred->gid != tcred->sgid || | |
139 | cred->gid != tcred->gid) && | |
140 | !capable(CAP_SYS_PTRACE)) { | |
141 | rcu_read_unlock(); | |
ab8d11be | 142 | return -EPERM; |
c69e8d9c DH |
143 | } |
144 | rcu_read_unlock(); | |
ab8d11be | 145 | smp_rmb(); |
df26c40e | 146 | if (task->mm) |
6c5d5238 | 147 | dumpable = get_dumpable(task->mm); |
df26c40e | 148 | if (!dumpable && !capable(CAP_SYS_PTRACE)) |
ab8d11be MS |
149 | return -EPERM; |
150 | ||
5cd9c58f | 151 | return security_ptrace_may_access(task, mode); |
ab8d11be MS |
152 | } |
153 | ||
006ebb40 | 154 | bool ptrace_may_access(struct task_struct *task, unsigned int mode) |
ab8d11be MS |
155 | { |
156 | int err; | |
157 | task_lock(task); | |
006ebb40 | 158 | err = __ptrace_may_access(task, mode); |
ab8d11be | 159 | task_unlock(task); |
006ebb40 | 160 | return (!err ? true : false); |
ab8d11be MS |
161 | } |
162 | ||
1da177e4 LT |
163 | int ptrace_attach(struct task_struct *task) |
164 | { | |
165 | int retval; | |
6175ecfe | 166 | unsigned long flags; |
f5b40e36 | 167 | |
a5cb013d AV |
168 | audit_ptrace(task); |
169 | ||
1da177e4 | 170 | retval = -EPERM; |
bac0abd6 | 171 | if (same_thread_group(task, current)) |
f5b40e36 LT |
172 | goto out; |
173 | ||
d84f4f99 DH |
174 | /* Protect exec's credential calculations against our interference; |
175 | * SUID, SGID and LSM creds get determined differently under ptrace. | |
176 | */ | |
177 | retval = mutex_lock_interruptible(¤t->cred_exec_mutex); | |
178 | if (retval < 0) | |
179 | goto out; | |
180 | ||
181 | retval = -EPERM; | |
f358166a LT |
182 | repeat: |
183 | /* | |
184 | * Nasty, nasty. | |
185 | * | |
186 | * We want to hold both the task-lock and the | |
187 | * tasklist_lock for writing at the same time. | |
188 | * But that's against the rules (tasklist_lock | |
189 | * is taken for reading by interrupts on other | |
190 | * cpu's that may have task_lock). | |
191 | */ | |
f5b40e36 | 192 | task_lock(task); |
6175ecfe | 193 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { |
f358166a LT |
194 | task_unlock(task); |
195 | do { | |
196 | cpu_relax(); | |
197 | } while (!write_can_lock(&tasklist_lock)); | |
198 | goto repeat; | |
199 | } | |
f5b40e36 | 200 | |
df26c40e EB |
201 | if (!task->mm) |
202 | goto bad; | |
1da177e4 LT |
203 | /* the same process cannot be attached many times */ |
204 | if (task->ptrace & PT_PTRACED) | |
205 | goto bad; | |
006ebb40 | 206 | retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH); |
1da177e4 LT |
207 | if (retval) |
208 | goto bad; | |
209 | ||
210 | /* Go */ | |
6b39c7bf | 211 | task->ptrace |= PT_PTRACED; |
1da177e4 LT |
212 | if (capable(CAP_SYS_PTRACE)) |
213 | task->ptrace |= PT_PTRACE_CAP; | |
1da177e4 | 214 | |
1da177e4 | 215 | __ptrace_link(task, current); |
1da177e4 | 216 | |
33e9fc7d | 217 | send_sig_info(SIGSTOP, SEND_SIG_FORCED, task); |
1da177e4 | 218 | bad: |
6175ecfe | 219 | write_unlock_irqrestore(&tasklist_lock, flags); |
1da177e4 | 220 | task_unlock(task); |
d84f4f99 | 221 | mutex_unlock(¤t->cred_exec_mutex); |
f5b40e36 | 222 | out: |
1da177e4 LT |
223 | return retval; |
224 | } | |
225 | ||
d5f70c00 | 226 | static inline void __ptrace_detach(struct task_struct *child, unsigned int data) |
5ecfbae0 ON |
227 | { |
228 | child->exit_code = data; | |
229 | /* .. re-parent .. */ | |
230 | __ptrace_unlink(child); | |
231 | /* .. and wake it up. */ | |
232 | if (child->exit_state != EXIT_ZOMBIE) | |
233 | wake_up_process(child); | |
234 | } | |
235 | ||
1da177e4 LT |
236 | int ptrace_detach(struct task_struct *child, unsigned int data) |
237 | { | |
7ed20e1a | 238 | if (!valid_signal(data)) |
5ecfbae0 | 239 | return -EIO; |
1da177e4 LT |
240 | |
241 | /* Architecture-specific hardware disable .. */ | |
242 | ptrace_disable(child); | |
7d941432 | 243 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); |
1da177e4 | 244 | |
1da177e4 | 245 | write_lock_irq(&tasklist_lock); |
d5f70c00 | 246 | /* protect against de_thread()->release_task() */ |
5ecfbae0 ON |
247 | if (child->ptrace) |
248 | __ptrace_detach(child, data); | |
1da177e4 LT |
249 | write_unlock_irq(&tasklist_lock); |
250 | ||
251 | return 0; | |
252 | } | |
253 | ||
1da177e4 LT |
254 | int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len) |
255 | { | |
256 | int copied = 0; | |
257 | ||
258 | while (len > 0) { | |
259 | char buf[128]; | |
260 | int this_len, retval; | |
261 | ||
262 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
263 | retval = access_process_vm(tsk, src, buf, this_len, 0); | |
264 | if (!retval) { | |
265 | if (copied) | |
266 | break; | |
267 | return -EIO; | |
268 | } | |
269 | if (copy_to_user(dst, buf, retval)) | |
270 | return -EFAULT; | |
271 | copied += retval; | |
272 | src += retval; | |
273 | dst += retval; | |
274 | len -= retval; | |
275 | } | |
276 | return copied; | |
277 | } | |
278 | ||
279 | int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len) | |
280 | { | |
281 | int copied = 0; | |
282 | ||
283 | while (len > 0) { | |
284 | char buf[128]; | |
285 | int this_len, retval; | |
286 | ||
287 | this_len = (len > sizeof(buf)) ? sizeof(buf) : len; | |
288 | if (copy_from_user(buf, src, this_len)) | |
289 | return -EFAULT; | |
290 | retval = access_process_vm(tsk, dst, buf, this_len, 1); | |
291 | if (!retval) { | |
292 | if (copied) | |
293 | break; | |
294 | return -EIO; | |
295 | } | |
296 | copied += retval; | |
297 | src += retval; | |
298 | dst += retval; | |
299 | len -= retval; | |
300 | } | |
301 | return copied; | |
302 | } | |
303 | ||
304 | static int ptrace_setoptions(struct task_struct *child, long data) | |
305 | { | |
306 | child->ptrace &= ~PT_TRACE_MASK; | |
307 | ||
308 | if (data & PTRACE_O_TRACESYSGOOD) | |
309 | child->ptrace |= PT_TRACESYSGOOD; | |
310 | ||
311 | if (data & PTRACE_O_TRACEFORK) | |
312 | child->ptrace |= PT_TRACE_FORK; | |
313 | ||
314 | if (data & PTRACE_O_TRACEVFORK) | |
315 | child->ptrace |= PT_TRACE_VFORK; | |
316 | ||
317 | if (data & PTRACE_O_TRACECLONE) | |
318 | child->ptrace |= PT_TRACE_CLONE; | |
319 | ||
320 | if (data & PTRACE_O_TRACEEXEC) | |
321 | child->ptrace |= PT_TRACE_EXEC; | |
322 | ||
323 | if (data & PTRACE_O_TRACEVFORKDONE) | |
324 | child->ptrace |= PT_TRACE_VFORK_DONE; | |
325 | ||
326 | if (data & PTRACE_O_TRACEEXIT) | |
327 | child->ptrace |= PT_TRACE_EXIT; | |
328 | ||
329 | return (data & ~PTRACE_O_MASK) ? -EINVAL : 0; | |
330 | } | |
331 | ||
e16b2781 | 332 | static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info) |
1da177e4 | 333 | { |
1da177e4 LT |
334 | int error = -ESRCH; |
335 | ||
336 | read_lock(&tasklist_lock); | |
337 | if (likely(child->sighand != NULL)) { | |
338 | error = -EINVAL; | |
339 | spin_lock_irq(&child->sighand->siglock); | |
340 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 341 | *info = *child->last_siginfo; |
1da177e4 LT |
342 | error = 0; |
343 | } | |
344 | spin_unlock_irq(&child->sighand->siglock); | |
345 | } | |
346 | read_unlock(&tasklist_lock); | |
1da177e4 LT |
347 | return error; |
348 | } | |
349 | ||
e16b2781 | 350 | static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info) |
1da177e4 | 351 | { |
1da177e4 LT |
352 | int error = -ESRCH; |
353 | ||
1da177e4 LT |
354 | read_lock(&tasklist_lock); |
355 | if (likely(child->sighand != NULL)) { | |
356 | error = -EINVAL; | |
357 | spin_lock_irq(&child->sighand->siglock); | |
358 | if (likely(child->last_siginfo != NULL)) { | |
e16b2781 | 359 | *child->last_siginfo = *info; |
1da177e4 LT |
360 | error = 0; |
361 | } | |
362 | spin_unlock_irq(&child->sighand->siglock); | |
363 | } | |
364 | read_unlock(&tasklist_lock); | |
365 | return error; | |
366 | } | |
367 | ||
36df29d7 RM |
368 | |
369 | #ifdef PTRACE_SINGLESTEP | |
370 | #define is_singlestep(request) ((request) == PTRACE_SINGLESTEP) | |
371 | #else | |
372 | #define is_singlestep(request) 0 | |
373 | #endif | |
374 | ||
5b88abbf RM |
375 | #ifdef PTRACE_SINGLEBLOCK |
376 | #define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK) | |
377 | #else | |
378 | #define is_singleblock(request) 0 | |
379 | #endif | |
380 | ||
36df29d7 RM |
381 | #ifdef PTRACE_SYSEMU |
382 | #define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP) | |
383 | #else | |
384 | #define is_sysemu_singlestep(request) 0 | |
385 | #endif | |
386 | ||
387 | static int ptrace_resume(struct task_struct *child, long request, long data) | |
388 | { | |
389 | if (!valid_signal(data)) | |
390 | return -EIO; | |
391 | ||
392 | if (request == PTRACE_SYSCALL) | |
393 | set_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
394 | else | |
395 | clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE); | |
396 | ||
397 | #ifdef TIF_SYSCALL_EMU | |
398 | if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP) | |
399 | set_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
400 | else | |
401 | clear_tsk_thread_flag(child, TIF_SYSCALL_EMU); | |
402 | #endif | |
403 | ||
5b88abbf RM |
404 | if (is_singleblock(request)) { |
405 | if (unlikely(!arch_has_block_step())) | |
406 | return -EIO; | |
407 | user_enable_block_step(child); | |
408 | } else if (is_singlestep(request) || is_sysemu_singlestep(request)) { | |
36df29d7 RM |
409 | if (unlikely(!arch_has_single_step())) |
410 | return -EIO; | |
411 | user_enable_single_step(child); | |
412 | } | |
413 | else | |
414 | user_disable_single_step(child); | |
415 | ||
416 | child->exit_code = data; | |
417 | wake_up_process(child); | |
418 | ||
419 | return 0; | |
420 | } | |
421 | ||
1da177e4 LT |
422 | int ptrace_request(struct task_struct *child, long request, |
423 | long addr, long data) | |
424 | { | |
425 | int ret = -EIO; | |
e16b2781 | 426 | siginfo_t siginfo; |
1da177e4 LT |
427 | |
428 | switch (request) { | |
16c3e389 RM |
429 | case PTRACE_PEEKTEXT: |
430 | case PTRACE_PEEKDATA: | |
431 | return generic_ptrace_peekdata(child, addr, data); | |
432 | case PTRACE_POKETEXT: | |
433 | case PTRACE_POKEDATA: | |
434 | return generic_ptrace_pokedata(child, addr, data); | |
435 | ||
1da177e4 LT |
436 | #ifdef PTRACE_OLDSETOPTIONS |
437 | case PTRACE_OLDSETOPTIONS: | |
438 | #endif | |
439 | case PTRACE_SETOPTIONS: | |
440 | ret = ptrace_setoptions(child, data); | |
441 | break; | |
442 | case PTRACE_GETEVENTMSG: | |
443 | ret = put_user(child->ptrace_message, (unsigned long __user *) data); | |
444 | break; | |
e16b2781 | 445 | |
1da177e4 | 446 | case PTRACE_GETSIGINFO: |
e16b2781 RM |
447 | ret = ptrace_getsiginfo(child, &siginfo); |
448 | if (!ret) | |
449 | ret = copy_siginfo_to_user((siginfo_t __user *) data, | |
450 | &siginfo); | |
1da177e4 | 451 | break; |
e16b2781 | 452 | |
1da177e4 | 453 | case PTRACE_SETSIGINFO: |
e16b2781 RM |
454 | if (copy_from_user(&siginfo, (siginfo_t __user *) data, |
455 | sizeof siginfo)) | |
456 | ret = -EFAULT; | |
457 | else | |
458 | ret = ptrace_setsiginfo(child, &siginfo); | |
1da177e4 | 459 | break; |
e16b2781 | 460 | |
1bcf5482 AD |
461 | case PTRACE_DETACH: /* detach a process that was attached. */ |
462 | ret = ptrace_detach(child, data); | |
463 | break; | |
36df29d7 RM |
464 | |
465 | #ifdef PTRACE_SINGLESTEP | |
466 | case PTRACE_SINGLESTEP: | |
467 | #endif | |
5b88abbf RM |
468 | #ifdef PTRACE_SINGLEBLOCK |
469 | case PTRACE_SINGLEBLOCK: | |
470 | #endif | |
36df29d7 RM |
471 | #ifdef PTRACE_SYSEMU |
472 | case PTRACE_SYSEMU: | |
473 | case PTRACE_SYSEMU_SINGLESTEP: | |
474 | #endif | |
475 | case PTRACE_SYSCALL: | |
476 | case PTRACE_CONT: | |
477 | return ptrace_resume(child, request, data); | |
478 | ||
479 | case PTRACE_KILL: | |
480 | if (child->exit_state) /* already dead */ | |
481 | return 0; | |
482 | return ptrace_resume(child, request, SIGKILL); | |
483 | ||
1da177e4 LT |
484 | default: |
485 | break; | |
486 | } | |
487 | ||
488 | return ret; | |
489 | } | |
481bed45 | 490 | |
6b9c7ed8 CH |
491 | /** |
492 | * ptrace_traceme -- helper for PTRACE_TRACEME | |
493 | * | |
494 | * Performs checks and sets PT_PTRACED. | |
495 | * Should be used by all ptrace implementations for PTRACE_TRACEME. | |
496 | */ | |
497 | int ptrace_traceme(void) | |
481bed45 | 498 | { |
f5b40e36 | 499 | int ret = -EPERM; |
481bed45 CH |
500 | |
501 | /* | |
6b9c7ed8 CH |
502 | * Are we already being traced? |
503 | */ | |
f470021a | 504 | repeat: |
f5b40e36 LT |
505 | task_lock(current); |
506 | if (!(current->ptrace & PT_PTRACED)) { | |
f470021a RM |
507 | /* |
508 | * See ptrace_attach() comments about the locking here. | |
509 | */ | |
510 | unsigned long flags; | |
511 | if (!write_trylock_irqsave(&tasklist_lock, flags)) { | |
512 | task_unlock(current); | |
513 | do { | |
514 | cpu_relax(); | |
515 | } while (!write_can_lock(&tasklist_lock)); | |
516 | goto repeat; | |
517 | } | |
518 | ||
5cd9c58f | 519 | ret = security_ptrace_traceme(current->parent); |
f470021a | 520 | |
f5b40e36 LT |
521 | /* |
522 | * Set the ptrace bit in the process ptrace flags. | |
f470021a | 523 | * Then link us on our parent's ptraced list. |
f5b40e36 | 524 | */ |
f470021a | 525 | if (!ret) { |
f5b40e36 | 526 | current->ptrace |= PT_PTRACED; |
f470021a RM |
527 | __ptrace_link(current, current->real_parent); |
528 | } | |
529 | ||
530 | write_unlock_irqrestore(&tasklist_lock, flags); | |
f5b40e36 LT |
531 | } |
532 | task_unlock(current); | |
533 | return ret; | |
6b9c7ed8 | 534 | } |
481bed45 | 535 | |
6b9c7ed8 CH |
536 | /** |
537 | * ptrace_get_task_struct -- grab a task struct reference for ptrace | |
538 | * @pid: process id to grab a task_struct reference of | |
539 | * | |
540 | * This function is a helper for ptrace implementations. It checks | |
541 | * permissions and then grabs a task struct for use of the actual | |
542 | * ptrace implementation. | |
543 | * | |
544 | * Returns the task_struct for @pid or an ERR_PTR() on failure. | |
545 | */ | |
546 | struct task_struct *ptrace_get_task_struct(pid_t pid) | |
547 | { | |
548 | struct task_struct *child; | |
481bed45 | 549 | |
481bed45 | 550 | read_lock(&tasklist_lock); |
228ebcbe | 551 | child = find_task_by_vpid(pid); |
481bed45 CH |
552 | if (child) |
553 | get_task_struct(child); | |
f400e198 | 554 | |
481bed45 CH |
555 | read_unlock(&tasklist_lock); |
556 | if (!child) | |
6b9c7ed8 CH |
557 | return ERR_PTR(-ESRCH); |
558 | return child; | |
481bed45 CH |
559 | } |
560 | ||
0ac15559 CH |
561 | #ifndef arch_ptrace_attach |
562 | #define arch_ptrace_attach(child) do { } while (0) | |
563 | #endif | |
564 | ||
481bed45 CH |
565 | asmlinkage long sys_ptrace(long request, long pid, long addr, long data) |
566 | { | |
567 | struct task_struct *child; | |
568 | long ret; | |
569 | ||
570 | /* | |
571 | * This lock_kernel fixes a subtle race with suid exec | |
572 | */ | |
573 | lock_kernel(); | |
6b9c7ed8 CH |
574 | if (request == PTRACE_TRACEME) { |
575 | ret = ptrace_traceme(); | |
6ea6dd93 HS |
576 | if (!ret) |
577 | arch_ptrace_attach(current); | |
481bed45 | 578 | goto out; |
6b9c7ed8 CH |
579 | } |
580 | ||
581 | child = ptrace_get_task_struct(pid); | |
582 | if (IS_ERR(child)) { | |
583 | ret = PTR_ERR(child); | |
584 | goto out; | |
585 | } | |
481bed45 CH |
586 | |
587 | if (request == PTRACE_ATTACH) { | |
588 | ret = ptrace_attach(child); | |
0ac15559 CH |
589 | /* |
590 | * Some architectures need to do book-keeping after | |
591 | * a ptrace attach. | |
592 | */ | |
593 | if (!ret) | |
594 | arch_ptrace_attach(child); | |
005f18df | 595 | goto out_put_task_struct; |
481bed45 CH |
596 | } |
597 | ||
598 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
599 | if (ret < 0) | |
600 | goto out_put_task_struct; | |
601 | ||
602 | ret = arch_ptrace(child, request, addr, data); | |
603 | if (ret < 0) | |
604 | goto out_put_task_struct; | |
605 | ||
606 | out_put_task_struct: | |
607 | put_task_struct(child); | |
608 | out: | |
609 | unlock_kernel(); | |
610 | return ret; | |
611 | } | |
76647323 AD |
612 | |
613 | int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data) | |
614 | { | |
615 | unsigned long tmp; | |
616 | int copied; | |
617 | ||
618 | copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0); | |
619 | if (copied != sizeof(tmp)) | |
620 | return -EIO; | |
621 | return put_user(tmp, (unsigned long __user *)data); | |
622 | } | |
f284ce72 AD |
623 | |
624 | int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data) | |
625 | { | |
626 | int copied; | |
627 | ||
628 | copied = access_process_vm(tsk, addr, &data, sizeof(data), 1); | |
629 | return (copied == sizeof(data)) ? 0 : -EIO; | |
630 | } | |
032d82d9 | 631 | |
9d04d928 | 632 | #if defined CONFIG_COMPAT && defined __ARCH_WANT_COMPAT_SYS_PTRACE |
032d82d9 RM |
633 | #include <linux/compat.h> |
634 | ||
635 | int compat_ptrace_request(struct task_struct *child, compat_long_t request, | |
636 | compat_ulong_t addr, compat_ulong_t data) | |
637 | { | |
638 | compat_ulong_t __user *datap = compat_ptr(data); | |
639 | compat_ulong_t word; | |
e16b2781 | 640 | siginfo_t siginfo; |
032d82d9 RM |
641 | int ret; |
642 | ||
643 | switch (request) { | |
644 | case PTRACE_PEEKTEXT: | |
645 | case PTRACE_PEEKDATA: | |
646 | ret = access_process_vm(child, addr, &word, sizeof(word), 0); | |
647 | if (ret != sizeof(word)) | |
648 | ret = -EIO; | |
649 | else | |
650 | ret = put_user(word, datap); | |
651 | break; | |
652 | ||
653 | case PTRACE_POKETEXT: | |
654 | case PTRACE_POKEDATA: | |
655 | ret = access_process_vm(child, addr, &data, sizeof(data), 1); | |
656 | ret = (ret != sizeof(data) ? -EIO : 0); | |
657 | break; | |
658 | ||
659 | case PTRACE_GETEVENTMSG: | |
660 | ret = put_user((compat_ulong_t) child->ptrace_message, datap); | |
661 | break; | |
662 | ||
e16b2781 RM |
663 | case PTRACE_GETSIGINFO: |
664 | ret = ptrace_getsiginfo(child, &siginfo); | |
665 | if (!ret) | |
666 | ret = copy_siginfo_to_user32( | |
667 | (struct compat_siginfo __user *) datap, | |
668 | &siginfo); | |
669 | break; | |
670 | ||
671 | case PTRACE_SETSIGINFO: | |
672 | memset(&siginfo, 0, sizeof siginfo); | |
673 | if (copy_siginfo_from_user32( | |
674 | &siginfo, (struct compat_siginfo __user *) datap)) | |
675 | ret = -EFAULT; | |
676 | else | |
677 | ret = ptrace_setsiginfo(child, &siginfo); | |
678 | break; | |
679 | ||
032d82d9 RM |
680 | default: |
681 | ret = ptrace_request(child, request, addr, data); | |
682 | } | |
683 | ||
684 | return ret; | |
685 | } | |
c269f196 | 686 | |
c269f196 RM |
687 | asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid, |
688 | compat_long_t addr, compat_long_t data) | |
689 | { | |
690 | struct task_struct *child; | |
691 | long ret; | |
692 | ||
693 | /* | |
694 | * This lock_kernel fixes a subtle race with suid exec | |
695 | */ | |
696 | lock_kernel(); | |
697 | if (request == PTRACE_TRACEME) { | |
698 | ret = ptrace_traceme(); | |
699 | goto out; | |
700 | } | |
701 | ||
702 | child = ptrace_get_task_struct(pid); | |
703 | if (IS_ERR(child)) { | |
704 | ret = PTR_ERR(child); | |
705 | goto out; | |
706 | } | |
707 | ||
708 | if (request == PTRACE_ATTACH) { | |
709 | ret = ptrace_attach(child); | |
710 | /* | |
711 | * Some architectures need to do book-keeping after | |
712 | * a ptrace attach. | |
713 | */ | |
714 | if (!ret) | |
715 | arch_ptrace_attach(child); | |
716 | goto out_put_task_struct; | |
717 | } | |
718 | ||
719 | ret = ptrace_check_attach(child, request == PTRACE_KILL); | |
720 | if (!ret) | |
721 | ret = compat_arch_ptrace(child, request, addr, data); | |
722 | ||
723 | out_put_task_struct: | |
724 | put_task_struct(child); | |
725 | out: | |
726 | unlock_kernel(); | |
727 | return ret; | |
728 | } | |
9d04d928 | 729 | #endif /* CONFIG_COMPAT && __ARCH_WANT_COMPAT_SYS_PTRACE */ |