blob: 29dc700e198cb71f3854aa632078f5d3d529c1a0 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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
Randy.Dunlapc59ede72006-01-11 12:17:46 -080010#include <linux/capability.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070011#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>
Jesper Juhl7ed20e12005-05-01 08:59:14 -070020#include <linux/signal.h>
Al Viroa5cb0132007-03-20 13:58:35 -040021#include <linux/audit.h>
Pavel Emelyanovb4888932007-10-18 23:40:14 -070022#include <linux/pid_namespace.h>
Adrian Bunkf17d30a2008-02-06 01:36:44 -080023#include <linux/syscalls.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070024
25#include <asm/pgtable.h>
26#include <asm/uaccess.h>
27
Markus Metzgerbf53de92008-12-19 15:10:24 +010028
29/*
30 * Initialize a new task whose father had been ptraced.
31 *
32 * Called from copy_process().
33 */
34void ptrace_fork(struct task_struct *child, unsigned long clone_flags)
35{
36 arch_ptrace_fork(child, clone_flags);
37}
38
Linus Torvalds1da177e2005-04-16 15:20:36 -070039/*
40 * ptrace a task: make the debugger its new parent and
41 * move it to the ptrace list.
42 *
43 * Must be called with the tasklist lock write-held.
44 */
Ingo Molnar36c8b582006-07-03 00:25:41 -070045void __ptrace_link(struct task_struct *child, struct task_struct *new_parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -070046{
Roland McGrathf4700212008-03-24 18:36:23 -070047 BUG_ON(!list_empty(&child->ptrace_entry));
48 list_add(&child->ptrace_entry, &new_parent->ptraced);
Linus Torvalds1da177e2005-04-16 15:20:36 -070049 child->parent = new_parent;
Linus Torvalds1da177e2005-04-16 15:20:36 -070050}
51
52/*
53 * Turn a tracing stop into a normal stop now, since with no tracer there
54 * would be no way to wake it up with SIGCONT or SIGKILL. If there was a
55 * signal sent that would resume the child, but didn't because it was in
56 * TASK_TRACED, resume it now.
57 * Requires that irqs be disabled.
58 */
Adrian Bunkb747c8c2008-10-18 20:28:21 -070059static void ptrace_untrace(struct task_struct *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -070060{
61 spin_lock(&child->sighand->siglock);
Matthew Wilcox6618a3e2007-12-06 11:06:16 -050062 if (task_is_traced(child)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -070063 if (child->signal->flags & SIGNAL_STOP_STOPPED) {
Oleg Nesterovd9ae90a2008-02-06 01:36:13 -080064 __set_task_state(child, TASK_STOPPED);
Linus Torvalds1da177e2005-04-16 15:20:36 -070065 } else {
66 signal_wake_up(child, 1);
67 }
68 }
69 spin_unlock(&child->sighand->siglock);
70}
71
72/*
73 * unptrace a task: move it back to its original parent and
74 * remove it from the ptrace list.
75 *
76 * Must be called with the tasklist lock write-held.
77 */
Ingo Molnar36c8b582006-07-03 00:25:41 -070078void __ptrace_unlink(struct task_struct *child)
Linus Torvalds1da177e2005-04-16 15:20:36 -070079{
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +030080 BUG_ON(!child->ptrace);
81
Linus Torvalds1da177e2005-04-16 15:20:36 -070082 child->ptrace = 0;
Roland McGrathf4700212008-03-24 18:36:23 -070083 child->parent = child->real_parent;
84 list_del_init(&child->ptrace_entry);
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Markus Metzgerbf53de92008-12-19 15:10:24 +010086 arch_ptrace_untrace(child);
Matthew Wilcox6618a3e2007-12-06 11:06:16 -050087 if (task_is_traced(child))
Roland McGrathe57a5052006-04-12 16:30:20 -070088 ptrace_untrace(child);
Linus Torvalds1da177e2005-04-16 15:20:36 -070089}
90
91/*
92 * Check that we have indeed attached to the thing..
93 */
94int ptrace_check_attach(struct task_struct *child, int kill)
95{
96 int ret = -ESRCH;
97
98 /*
99 * We take the read lock around doing both checks to close a
100 * possible race where someone else was tracing our child and
101 * detached between these two checks. After this locked check,
102 * we are sure that this is our traced child and that can only
103 * be changed by us so it's not changing right after this.
104 */
105 read_lock(&tasklist_lock);
Oleg Nesterovc0c0b642008-02-08 04:19:00 -0800106 if ((child->ptrace & PT_PTRACED) && child->parent == current) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107 ret = 0;
Oleg Nesterovc0c0b642008-02-08 04:19:00 -0800108 /*
109 * child->sighand can't be NULL, release_task()
110 * does ptrace_unlink() before __exit_signal().
111 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112 spin_lock_irq(&child->sighand->siglock);
Oleg Nesterovd9ae90a2008-02-06 01:36:13 -0800113 if (task_is_stopped(child))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114 child->state = TASK_TRACED;
Oleg Nesterovd9ae90a2008-02-06 01:36:13 -0800115 else if (!task_is_traced(child) && !kill)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116 ret = -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 spin_unlock_irq(&child->sighand->siglock);
118 }
119 read_unlock(&tasklist_lock);
120
Oleg Nesterovd9ae90a2008-02-06 01:36:13 -0800121 if (!ret && !kill)
Roland McGrath85ba2d82008-07-25 19:45:58 -0700122 ret = wait_task_inactive(child, TASK_TRACED) ? 0 : -ESRCH;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700123
124 /* All systems go.. */
125 return ret;
126}
127
Stephen Smalley006ebb42008-05-19 08:32:49 -0400128int __ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700129{
David Howellsc69e8d92008-11-14 10:39:19 +1100130 const struct cred *cred = current_cred(), *tcred;
David Howellsb6dff3e2008-11-14 10:39:16 +1100131
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700132 /* May we inspect the given task?
133 * This check is used both for attaching with ptrace
134 * and for allowing access to sensitive information in /proc.
135 *
136 * ptrace_attach denies several cases that /proc allows
137 * because setting up the necessary parent/child relationship
138 * or halting the specified task is impossible.
139 */
140 int dumpable = 0;
141 /* Don't let security modules deny introspection */
142 if (task == current)
143 return 0;
David Howellsc69e8d92008-11-14 10:39:19 +1100144 rcu_read_lock();
145 tcred = __task_cred(task);
146 if ((cred->uid != tcred->euid ||
147 cred->uid != tcred->suid ||
148 cred->uid != tcred->uid ||
149 cred->gid != tcred->egid ||
150 cred->gid != tcred->sgid ||
151 cred->gid != tcred->gid) &&
152 !capable(CAP_SYS_PTRACE)) {
153 rcu_read_unlock();
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700154 return -EPERM;
David Howellsc69e8d92008-11-14 10:39:19 +1100155 }
156 rcu_read_unlock();
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700157 smp_rmb();
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700158 if (task->mm)
Kawai, Hidehiro6c5d5232007-07-19 01:48:27 -0700159 dumpable = get_dumpable(task->mm);
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700160 if (!dumpable && !capable(CAP_SYS_PTRACE))
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700161 return -EPERM;
162
David Howells5cd9c582008-08-14 11:37:28 +0100163 return security_ptrace_may_access(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700164}
165
Stephen Smalley006ebb42008-05-19 08:32:49 -0400166bool ptrace_may_access(struct task_struct *task, unsigned int mode)
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700167{
168 int err;
169 task_lock(task);
Stephen Smalley006ebb42008-05-19 08:32:49 -0400170 err = __ptrace_may_access(task, mode);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700171 task_unlock(task);
Stephen Smalley006ebb42008-05-19 08:32:49 -0400172 return (!err ? true : false);
Miklos Szerediab8d11b2005-09-06 15:18:24 -0700173}
174
Linus Torvalds1da177e2005-04-16 15:20:36 -0700175int ptrace_attach(struct task_struct *task)
176{
177 int retval;
Sripathi Kodi6175ecf2007-07-15 23:39:26 -0700178 unsigned long flags;
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700179
Al Viroa5cb0132007-03-20 13:58:35 -0400180 audit_ptrace(task);
181
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 retval = -EPERM;
Pavel Emelyanovbac0abd2007-10-18 23:40:18 -0700183 if (same_thread_group(task, current))
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700184 goto out;
185
David Howellsd84f4f92008-11-14 10:39:23 +1100186 /* Protect exec's credential calculations against our interference;
187 * SUID, SGID and LSM creds get determined differently under ptrace.
188 */
189 retval = mutex_lock_interruptible(&current->cred_exec_mutex);
190 if (retval < 0)
191 goto out;
192
193 retval = -EPERM;
Linus Torvaldsf3581662006-05-11 11:08:49 -0700194repeat:
195 /*
196 * Nasty, nasty.
197 *
198 * We want to hold both the task-lock and the
199 * tasklist_lock for writing at the same time.
200 * But that's against the rules (tasklist_lock
201 * is taken for reading by interrupts on other
202 * cpu's that may have task_lock).
203 */
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700204 task_lock(task);
Sripathi Kodi6175ecf2007-07-15 23:39:26 -0700205 if (!write_trylock_irqsave(&tasklist_lock, flags)) {
Linus Torvaldsf3581662006-05-11 11:08:49 -0700206 task_unlock(task);
207 do {
208 cpu_relax();
209 } while (!write_can_lock(&tasklist_lock));
210 goto repeat;
211 }
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700212
Eric W. Biedermandf26c402006-06-26 00:25:59 -0700213 if (!task->mm)
214 goto bad;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700215 /* the same process cannot be attached many times */
216 if (task->ptrace & PT_PTRACED)
217 goto bad;
Stephen Smalley006ebb42008-05-19 08:32:49 -0400218 retval = __ptrace_may_access(task, PTRACE_MODE_ATTACH);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700219 if (retval)
220 goto bad;
221
222 /* Go */
Oleg Nesterov6b39c7b2008-02-08 04:18:58 -0800223 task->ptrace |= PT_PTRACED;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700224 if (capable(CAP_SYS_PTRACE))
225 task->ptrace |= PT_PTRACE_CAP;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700226
Linus Torvalds1da177e2005-04-16 15:20:36 -0700227 __ptrace_link(task, current);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700228
Oleg Nesterov33e9fc72008-04-30 00:53:14 -0700229 send_sig_info(SIGSTOP, SEND_SIG_FORCED, task);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700230bad:
Sripathi Kodi6175ecf2007-07-15 23:39:26 -0700231 write_unlock_irqrestore(&tasklist_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700232 task_unlock(task);
David Howellsd84f4f92008-11-14 10:39:23 +1100233 mutex_unlock(&current->cred_exec_mutex);
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700234out:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700235 return retval;
236}
237
Oleg Nesterovd5f70c02006-06-26 00:26:07 -0700238static inline void __ptrace_detach(struct task_struct *child, unsigned int data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700239{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700240 child->exit_code = data;
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300241 /* .. re-parent .. */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700242 __ptrace_unlink(child);
243 /* .. and wake it up. */
244 if (child->exit_state != EXIT_ZOMBIE)
245 wake_up_process(child);
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300246}
247
248int ptrace_detach(struct task_struct *child, unsigned int data)
249{
250 if (!valid_signal(data))
251 return -EIO;
252
253 /* Architecture-specific hardware disable .. */
254 ptrace_disable(child);
Roland McGrath7d941432007-09-05 03:05:56 -0700255 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300256
257 write_lock_irq(&tasklist_lock);
Oleg Nesterovd5f70c02006-06-26 00:26:07 -0700258 /* protect against de_thread()->release_task() */
Oleg Nesterov5ecfbae2006-02-15 22:50:10 +0300259 if (child->ptrace)
260 __ptrace_detach(child, data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261 write_unlock_irq(&tasklist_lock);
262
263 return 0;
264}
265
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266int ptrace_readdata(struct task_struct *tsk, unsigned long src, char __user *dst, int len)
267{
268 int copied = 0;
269
270 while (len > 0) {
271 char buf[128];
272 int this_len, retval;
273
274 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
275 retval = access_process_vm(tsk, src, buf, this_len, 0);
276 if (!retval) {
277 if (copied)
278 break;
279 return -EIO;
280 }
281 if (copy_to_user(dst, buf, retval))
282 return -EFAULT;
283 copied += retval;
284 src += retval;
285 dst += retval;
286 len -= retval;
287 }
288 return copied;
289}
290
291int ptrace_writedata(struct task_struct *tsk, char __user *src, unsigned long dst, int len)
292{
293 int copied = 0;
294
295 while (len > 0) {
296 char buf[128];
297 int this_len, retval;
298
299 this_len = (len > sizeof(buf)) ? sizeof(buf) : len;
300 if (copy_from_user(buf, src, this_len))
301 return -EFAULT;
302 retval = access_process_vm(tsk, dst, buf, this_len, 1);
303 if (!retval) {
304 if (copied)
305 break;
306 return -EIO;
307 }
308 copied += retval;
309 src += retval;
310 dst += retval;
311 len -= retval;
312 }
313 return copied;
314}
315
316static int ptrace_setoptions(struct task_struct *child, long data)
317{
318 child->ptrace &= ~PT_TRACE_MASK;
319
320 if (data & PTRACE_O_TRACESYSGOOD)
321 child->ptrace |= PT_TRACESYSGOOD;
322
323 if (data & PTRACE_O_TRACEFORK)
324 child->ptrace |= PT_TRACE_FORK;
325
326 if (data & PTRACE_O_TRACEVFORK)
327 child->ptrace |= PT_TRACE_VFORK;
328
329 if (data & PTRACE_O_TRACECLONE)
330 child->ptrace |= PT_TRACE_CLONE;
331
332 if (data & PTRACE_O_TRACEEXEC)
333 child->ptrace |= PT_TRACE_EXEC;
334
335 if (data & PTRACE_O_TRACEVFORKDONE)
336 child->ptrace |= PT_TRACE_VFORK_DONE;
337
338 if (data & PTRACE_O_TRACEEXIT)
339 child->ptrace |= PT_TRACE_EXIT;
340
341 return (data & ~PTRACE_O_MASK) ? -EINVAL : 0;
342}
343
Roland McGrathe16b2782008-04-20 13:10:12 -0700344static int ptrace_getsiginfo(struct task_struct *child, siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700345{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700346 int error = -ESRCH;
347
348 read_lock(&tasklist_lock);
349 if (likely(child->sighand != NULL)) {
350 error = -EINVAL;
351 spin_lock_irq(&child->sighand->siglock);
352 if (likely(child->last_siginfo != NULL)) {
Roland McGrathe16b2782008-04-20 13:10:12 -0700353 *info = *child->last_siginfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700354 error = 0;
355 }
356 spin_unlock_irq(&child->sighand->siglock);
357 }
358 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 return error;
360}
361
Roland McGrathe16b2782008-04-20 13:10:12 -0700362static int ptrace_setsiginfo(struct task_struct *child, const siginfo_t *info)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364 int error = -ESRCH;
365
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 read_lock(&tasklist_lock);
367 if (likely(child->sighand != NULL)) {
368 error = -EINVAL;
369 spin_lock_irq(&child->sighand->siglock);
370 if (likely(child->last_siginfo != NULL)) {
Roland McGrathe16b2782008-04-20 13:10:12 -0700371 *child->last_siginfo = *info;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 error = 0;
373 }
374 spin_unlock_irq(&child->sighand->siglock);
375 }
376 read_unlock(&tasklist_lock);
377 return error;
378}
379
Roland McGrath36df29d2008-01-30 13:30:51 +0100380
381#ifdef PTRACE_SINGLESTEP
382#define is_singlestep(request) ((request) == PTRACE_SINGLESTEP)
383#else
384#define is_singlestep(request) 0
385#endif
386
Roland McGrath5b88abb2008-01-30 13:30:53 +0100387#ifdef PTRACE_SINGLEBLOCK
388#define is_singleblock(request) ((request) == PTRACE_SINGLEBLOCK)
389#else
390#define is_singleblock(request) 0
391#endif
392
Roland McGrath36df29d2008-01-30 13:30:51 +0100393#ifdef PTRACE_SYSEMU
394#define is_sysemu_singlestep(request) ((request) == PTRACE_SYSEMU_SINGLESTEP)
395#else
396#define is_sysemu_singlestep(request) 0
397#endif
398
399static int ptrace_resume(struct task_struct *child, long request, long data)
400{
401 if (!valid_signal(data))
402 return -EIO;
403
404 if (request == PTRACE_SYSCALL)
405 set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
406 else
407 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
408
409#ifdef TIF_SYSCALL_EMU
410 if (request == PTRACE_SYSEMU || request == PTRACE_SYSEMU_SINGLESTEP)
411 set_tsk_thread_flag(child, TIF_SYSCALL_EMU);
412 else
413 clear_tsk_thread_flag(child, TIF_SYSCALL_EMU);
414#endif
415
Roland McGrath5b88abb2008-01-30 13:30:53 +0100416 if (is_singleblock(request)) {
417 if (unlikely(!arch_has_block_step()))
418 return -EIO;
419 user_enable_block_step(child);
420 } else if (is_singlestep(request) || is_sysemu_singlestep(request)) {
Roland McGrath36df29d2008-01-30 13:30:51 +0100421 if (unlikely(!arch_has_single_step()))
422 return -EIO;
423 user_enable_single_step(child);
424 }
425 else
426 user_disable_single_step(child);
427
428 child->exit_code = data;
429 wake_up_process(child);
430
431 return 0;
432}
433
Linus Torvalds1da177e2005-04-16 15:20:36 -0700434int ptrace_request(struct task_struct *child, long request,
435 long addr, long data)
436{
437 int ret = -EIO;
Roland McGrathe16b2782008-04-20 13:10:12 -0700438 siginfo_t siginfo;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439
440 switch (request) {
Roland McGrath16c3e382008-01-30 13:31:47 +0100441 case PTRACE_PEEKTEXT:
442 case PTRACE_PEEKDATA:
443 return generic_ptrace_peekdata(child, addr, data);
444 case PTRACE_POKETEXT:
445 case PTRACE_POKEDATA:
446 return generic_ptrace_pokedata(child, addr, data);
447
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448#ifdef PTRACE_OLDSETOPTIONS
449 case PTRACE_OLDSETOPTIONS:
450#endif
451 case PTRACE_SETOPTIONS:
452 ret = ptrace_setoptions(child, data);
453 break;
454 case PTRACE_GETEVENTMSG:
455 ret = put_user(child->ptrace_message, (unsigned long __user *) data);
456 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700457
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458 case PTRACE_GETSIGINFO:
Roland McGrathe16b2782008-04-20 13:10:12 -0700459 ret = ptrace_getsiginfo(child, &siginfo);
460 if (!ret)
461 ret = copy_siginfo_to_user((siginfo_t __user *) data,
462 &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700463 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700464
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465 case PTRACE_SETSIGINFO:
Roland McGrathe16b2782008-04-20 13:10:12 -0700466 if (copy_from_user(&siginfo, (siginfo_t __user *) data,
467 sizeof siginfo))
468 ret = -EFAULT;
469 else
470 ret = ptrace_setsiginfo(child, &siginfo);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700471 break;
Roland McGrathe16b2782008-04-20 13:10:12 -0700472
Alexey Dobriyan1bcf5482007-10-16 01:23:45 -0700473 case PTRACE_DETACH: /* detach a process that was attached. */
474 ret = ptrace_detach(child, data);
475 break;
Roland McGrath36df29d2008-01-30 13:30:51 +0100476
477#ifdef PTRACE_SINGLESTEP
478 case PTRACE_SINGLESTEP:
479#endif
Roland McGrath5b88abb2008-01-30 13:30:53 +0100480#ifdef PTRACE_SINGLEBLOCK
481 case PTRACE_SINGLEBLOCK:
482#endif
Roland McGrath36df29d2008-01-30 13:30:51 +0100483#ifdef PTRACE_SYSEMU
484 case PTRACE_SYSEMU:
485 case PTRACE_SYSEMU_SINGLESTEP:
486#endif
487 case PTRACE_SYSCALL:
488 case PTRACE_CONT:
489 return ptrace_resume(child, request, data);
490
491 case PTRACE_KILL:
492 if (child->exit_state) /* already dead */
493 return 0;
494 return ptrace_resume(child, request, SIGKILL);
495
Linus Torvalds1da177e2005-04-16 15:20:36 -0700496 default:
497 break;
498 }
499
500 return ret;
501}
Christoph Hellwig481bed42005-11-07 00:59:47 -0800502
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800503/**
504 * ptrace_traceme -- helper for PTRACE_TRACEME
505 *
506 * Performs checks and sets PT_PTRACED.
507 * Should be used by all ptrace implementations for PTRACE_TRACEME.
508 */
509int ptrace_traceme(void)
Christoph Hellwig481bed42005-11-07 00:59:47 -0800510{
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700511 int ret = -EPERM;
Christoph Hellwig481bed42005-11-07 00:59:47 -0800512
513 /*
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800514 * Are we already being traced?
Christoph Hellwig481bed42005-11-07 00:59:47 -0800515 */
Roland McGrathf4700212008-03-24 18:36:23 -0700516repeat:
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700517 task_lock(current);
518 if (!(current->ptrace & PT_PTRACED)) {
Roland McGrathf4700212008-03-24 18:36:23 -0700519 /*
520 * See ptrace_attach() comments about the locking here.
521 */
522 unsigned long flags;
523 if (!write_trylock_irqsave(&tasklist_lock, flags)) {
524 task_unlock(current);
525 do {
526 cpu_relax();
527 } while (!write_can_lock(&tasklist_lock));
528 goto repeat;
529 }
530
David Howells5cd9c582008-08-14 11:37:28 +0100531 ret = security_ptrace_traceme(current->parent);
Roland McGrathf4700212008-03-24 18:36:23 -0700532
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700533 /*
534 * Set the ptrace bit in the process ptrace flags.
Roland McGrathf4700212008-03-24 18:36:23 -0700535 * Then link us on our parent's ptraced list.
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700536 */
Roland McGrathf4700212008-03-24 18:36:23 -0700537 if (!ret) {
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700538 current->ptrace |= PT_PTRACED;
Roland McGrathf4700212008-03-24 18:36:23 -0700539 __ptrace_link(current, current->real_parent);
540 }
541
542 write_unlock_irqrestore(&tasklist_lock, flags);
Linus Torvaldsf5b40e32006-05-07 10:49:33 -0700543 }
544 task_unlock(current);
545 return ret;
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800546}
Christoph Hellwig481bed42005-11-07 00:59:47 -0800547
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800548/**
549 * ptrace_get_task_struct -- grab a task struct reference for ptrace
550 * @pid: process id to grab a task_struct reference of
551 *
552 * This function is a helper for ptrace implementations. It checks
553 * permissions and then grabs a task struct for use of the actual
554 * ptrace implementation.
555 *
556 * Returns the task_struct for @pid or an ERR_PTR() on failure.
557 */
558struct task_struct *ptrace_get_task_struct(pid_t pid)
559{
560 struct task_struct *child;
Christoph Hellwig481bed42005-11-07 00:59:47 -0800561
Christoph Hellwig481bed42005-11-07 00:59:47 -0800562 read_lock(&tasklist_lock);
Pavel Emelyanov228ebcb2007-10-18 23:40:16 -0700563 child = find_task_by_vpid(pid);
Christoph Hellwig481bed42005-11-07 00:59:47 -0800564 if (child)
565 get_task_struct(child);
Sukadev Bhattiproluf400e192006-09-29 02:00:07 -0700566
Christoph Hellwig481bed42005-11-07 00:59:47 -0800567 read_unlock(&tasklist_lock);
568 if (!child)
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800569 return ERR_PTR(-ESRCH);
570 return child;
Christoph Hellwig481bed42005-11-07 00:59:47 -0800571}
572
Christoph Hellwig0ac15552007-10-16 01:26:37 -0700573#ifndef arch_ptrace_attach
574#define arch_ptrace_attach(child) do { } while (0)
575#endif
576
Christoph Hellwig481bed42005-11-07 00:59:47 -0800577asmlinkage long sys_ptrace(long request, long pid, long addr, long data)
578{
579 struct task_struct *child;
580 long ret;
581
582 /*
583 * This lock_kernel fixes a subtle race with suid exec
584 */
585 lock_kernel();
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800586 if (request == PTRACE_TRACEME) {
587 ret = ptrace_traceme();
Haavard Skinnemoen6ea6dd92007-11-27 13:02:40 +0100588 if (!ret)
589 arch_ptrace_attach(current);
Christoph Hellwig481bed42005-11-07 00:59:47 -0800590 goto out;
Christoph Hellwig6b9c7ed2006-01-08 01:02:33 -0800591 }
592
593 child = ptrace_get_task_struct(pid);
594 if (IS_ERR(child)) {
595 ret = PTR_ERR(child);
596 goto out;
597 }
Christoph Hellwig481bed42005-11-07 00:59:47 -0800598
599 if (request == PTRACE_ATTACH) {
600 ret = ptrace_attach(child);
Christoph Hellwig0ac15552007-10-16 01:26:37 -0700601 /*
602 * Some architectures need to do book-keeping after
603 * a ptrace attach.
604 */
605 if (!ret)
606 arch_ptrace_attach(child);
Christoph Hellwig005f18d2005-11-13 16:06:33 -0800607 goto out_put_task_struct;
Christoph Hellwig481bed42005-11-07 00:59:47 -0800608 }
609
610 ret = ptrace_check_attach(child, request == PTRACE_KILL);
611 if (ret < 0)
612 goto out_put_task_struct;
613
614 ret = arch_ptrace(child, request, addr, data);
615 if (ret < 0)
616 goto out_put_task_struct;
617
618 out_put_task_struct:
619 put_task_struct(child);
620 out:
621 unlock_kernel();
622 return ret;
623}
Alexey Dobriyan76647322007-07-17 04:03:43 -0700624
625int generic_ptrace_peekdata(struct task_struct *tsk, long addr, long data)
626{
627 unsigned long tmp;
628 int copied;
629
630 copied = access_process_vm(tsk, addr, &tmp, sizeof(tmp), 0);
631 if (copied != sizeof(tmp))
632 return -EIO;
633 return put_user(tmp, (unsigned long __user *)data);
634}
Alexey Dobriyanf284ce72007-07-17 04:03:44 -0700635
636int generic_ptrace_pokedata(struct task_struct *tsk, long addr, long data)
637{
638 int copied;
639
640 copied = access_process_vm(tsk, addr, &data, sizeof(data), 1);
641 return (copied == sizeof(data)) ? 0 : -EIO;
642}
Roland McGrath032d82d2008-01-30 13:31:47 +0100643
Christoph Hellwig96b89362008-11-25 08:10:03 +0100644#if defined CONFIG_COMPAT
Roland McGrath032d82d2008-01-30 13:31:47 +0100645#include <linux/compat.h>
646
647int compat_ptrace_request(struct task_struct *child, compat_long_t request,
648 compat_ulong_t addr, compat_ulong_t data)
649{
650 compat_ulong_t __user *datap = compat_ptr(data);
651 compat_ulong_t word;
Roland McGrathe16b2782008-04-20 13:10:12 -0700652 siginfo_t siginfo;
Roland McGrath032d82d2008-01-30 13:31:47 +0100653 int ret;
654
655 switch (request) {
656 case PTRACE_PEEKTEXT:
657 case PTRACE_PEEKDATA:
658 ret = access_process_vm(child, addr, &word, sizeof(word), 0);
659 if (ret != sizeof(word))
660 ret = -EIO;
661 else
662 ret = put_user(word, datap);
663 break;
664
665 case PTRACE_POKETEXT:
666 case PTRACE_POKEDATA:
667 ret = access_process_vm(child, addr, &data, sizeof(data), 1);
668 ret = (ret != sizeof(data) ? -EIO : 0);
669 break;
670
671 case PTRACE_GETEVENTMSG:
672 ret = put_user((compat_ulong_t) child->ptrace_message, datap);
673 break;
674
Roland McGrathe16b2782008-04-20 13:10:12 -0700675 case PTRACE_GETSIGINFO:
676 ret = ptrace_getsiginfo(child, &siginfo);
677 if (!ret)
678 ret = copy_siginfo_to_user32(
679 (struct compat_siginfo __user *) datap,
680 &siginfo);
681 break;
682
683 case PTRACE_SETSIGINFO:
684 memset(&siginfo, 0, sizeof siginfo);
685 if (copy_siginfo_from_user32(
686 &siginfo, (struct compat_siginfo __user *) datap))
687 ret = -EFAULT;
688 else
689 ret = ptrace_setsiginfo(child, &siginfo);
690 break;
691
Roland McGrath032d82d2008-01-30 13:31:47 +0100692 default:
693 ret = ptrace_request(child, request, addr, data);
694 }
695
696 return ret;
697}
Roland McGrathc269f192008-01-30 13:31:48 +0100698
Roland McGrathc269f192008-01-30 13:31:48 +0100699asmlinkage long compat_sys_ptrace(compat_long_t request, compat_long_t pid,
700 compat_long_t addr, compat_long_t data)
701{
702 struct task_struct *child;
703 long ret;
704
705 /*
706 * This lock_kernel fixes a subtle race with suid exec
707 */
708 lock_kernel();
709 if (request == PTRACE_TRACEME) {
710 ret = ptrace_traceme();
711 goto out;
712 }
713
714 child = ptrace_get_task_struct(pid);
715 if (IS_ERR(child)) {
716 ret = PTR_ERR(child);
717 goto out;
718 }
719
720 if (request == PTRACE_ATTACH) {
721 ret = ptrace_attach(child);
722 /*
723 * Some architectures need to do book-keeping after
724 * a ptrace attach.
725 */
726 if (!ret)
727 arch_ptrace_attach(child);
728 goto out_put_task_struct;
729 }
730
731 ret = ptrace_check_attach(child, request == PTRACE_KILL);
732 if (!ret)
733 ret = compat_arch_ptrace(child, request, addr, data);
734
735 out_put_task_struct:
736 put_task_struct(child);
737 out:
738 unlock_kernel();
739 return ret;
740}
Christoph Hellwig96b89362008-11-25 08:10:03 +0100741#endif /* CONFIG_COMPAT */