Commit | Line | Data |
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10c28d93 AK |
1 | #include <linux/slab.h> |
2 | #include <linux/file.h> | |
3 | #include <linux/fdtable.h> | |
4 | #include <linux/mm.h> | |
5 | #include <linux/stat.h> | |
6 | #include <linux/fcntl.h> | |
7 | #include <linux/swap.h> | |
8 | #include <linux/string.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/pagemap.h> | |
11 | #include <linux/perf_event.h> | |
12 | #include <linux/highmem.h> | |
13 | #include <linux/spinlock.h> | |
14 | #include <linux/key.h> | |
15 | #include <linux/personality.h> | |
16 | #include <linux/binfmts.h> | |
179899fd | 17 | #include <linux/coredump.h> |
10c28d93 AK |
18 | #include <linux/utsname.h> |
19 | #include <linux/pid_namespace.h> | |
20 | #include <linux/module.h> | |
21 | #include <linux/namei.h> | |
22 | #include <linux/mount.h> | |
23 | #include <linux/security.h> | |
24 | #include <linux/syscalls.h> | |
25 | #include <linux/tsacct_kern.h> | |
26 | #include <linux/cn_proc.h> | |
27 | #include <linux/audit.h> | |
28 | #include <linux/tracehook.h> | |
29 | #include <linux/kmod.h> | |
30 | #include <linux/fsnotify.h> | |
31 | #include <linux/fs_struct.h> | |
32 | #include <linux/pipe_fs_i.h> | |
33 | #include <linux/oom.h> | |
34 | #include <linux/compat.h> | |
35 | ||
36 | #include <asm/uaccess.h> | |
37 | #include <asm/mmu_context.h> | |
38 | #include <asm/tlb.h> | |
39 | #include <asm/exec.h> | |
40 | ||
41 | #include <trace/events/task.h> | |
42 | #include "internal.h" | |
179899fd | 43 | #include "coredump.h" |
10c28d93 AK |
44 | |
45 | #include <trace/events/sched.h> | |
46 | ||
47 | int core_uses_pid; | |
10c28d93 | 48 | unsigned int core_pipe_limit; |
3ceadcf6 ON |
49 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
50 | static int core_name_size = CORENAME_MAX_SIZE; | |
10c28d93 AK |
51 | |
52 | struct core_name { | |
53 | char *corename; | |
54 | int used, size; | |
55 | }; | |
10c28d93 AK |
56 | |
57 | /* The maximal length of core_pattern is also specified in sysctl.c */ | |
58 | ||
3ceadcf6 | 59 | static int expand_corename(struct core_name *cn, int size) |
10c28d93 | 60 | { |
e7fd1549 | 61 | char *corename = krealloc(cn->corename, size, GFP_KERNEL); |
10c28d93 | 62 | |
e7fd1549 | 63 | if (!corename) |
10c28d93 | 64 | return -ENOMEM; |
10c28d93 | 65 | |
3ceadcf6 ON |
66 | if (size > core_name_size) /* racy but harmless */ |
67 | core_name_size = size; | |
68 | ||
69 | cn->size = ksize(corename); | |
e7fd1549 | 70 | cn->corename = corename; |
10c28d93 AK |
71 | return 0; |
72 | } | |
73 | ||
bc03c691 | 74 | static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg) |
10c28d93 | 75 | { |
5fe9d8ca | 76 | int free, need; |
10c28d93 | 77 | |
5fe9d8ca ON |
78 | again: |
79 | free = cn->size - cn->used; | |
80 | need = vsnprintf(cn->corename + cn->used, free, fmt, arg); | |
81 | if (need < free) { | |
82 | cn->used += need; | |
83 | return 0; | |
84 | } | |
10c28d93 | 85 | |
3ceadcf6 | 86 | if (!expand_corename(cn, cn->size + need - free + 1)) |
5fe9d8ca | 87 | goto again; |
10c28d93 | 88 | |
5fe9d8ca | 89 | return -ENOMEM; |
10c28d93 AK |
90 | } |
91 | ||
bc03c691 ON |
92 | static int cn_printf(struct core_name *cn, const char *fmt, ...) |
93 | { | |
94 | va_list arg; | |
95 | int ret; | |
96 | ||
97 | va_start(arg, fmt); | |
98 | ret = cn_vprintf(cn, fmt, arg); | |
99 | va_end(arg); | |
100 | ||
101 | return ret; | |
102 | } | |
103 | ||
923bed03 | 104 | static int cn_esc_printf(struct core_name *cn, const char *fmt, ...) |
10c28d93 | 105 | { |
923bed03 ON |
106 | int cur = cn->used; |
107 | va_list arg; | |
108 | int ret; | |
109 | ||
110 | va_start(arg, fmt); | |
111 | ret = cn_vprintf(cn, fmt, arg); | |
112 | va_end(arg); | |
113 | ||
114 | for (; cur < cn->used; ++cur) { | |
115 | if (cn->corename[cur] == '/') | |
116 | cn->corename[cur] = '!'; | |
117 | } | |
118 | return ret; | |
10c28d93 AK |
119 | } |
120 | ||
121 | static int cn_print_exe_file(struct core_name *cn) | |
122 | { | |
123 | struct file *exe_file; | |
124 | char *pathbuf, *path; | |
125 | int ret; | |
126 | ||
127 | exe_file = get_mm_exe_file(current->mm); | |
923bed03 ON |
128 | if (!exe_file) |
129 | return cn_esc_printf(cn, "%s (path unknown)", current->comm); | |
10c28d93 AK |
130 | |
131 | pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY); | |
132 | if (!pathbuf) { | |
133 | ret = -ENOMEM; | |
134 | goto put_exe_file; | |
135 | } | |
136 | ||
137 | path = d_path(&exe_file->f_path, pathbuf, PATH_MAX); | |
138 | if (IS_ERR(path)) { | |
139 | ret = PTR_ERR(path); | |
140 | goto free_buf; | |
141 | } | |
142 | ||
923bed03 | 143 | ret = cn_esc_printf(cn, "%s", path); |
10c28d93 AK |
144 | |
145 | free_buf: | |
146 | kfree(pathbuf); | |
147 | put_exe_file: | |
148 | fput(exe_file); | |
149 | return ret; | |
150 | } | |
151 | ||
152 | /* format_corename will inspect the pattern parameter, and output a | |
153 | * name into corename, which must have space for at least | |
154 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
155 | */ | |
12a2b4b2 | 156 | static int format_corename(struct core_name *cn, struct coredump_params *cprm) |
10c28d93 AK |
157 | { |
158 | const struct cred *cred = current_cred(); | |
159 | const char *pat_ptr = core_pattern; | |
160 | int ispipe = (*pat_ptr == '|'); | |
161 | int pid_in_pattern = 0; | |
162 | int err = 0; | |
163 | ||
e7fd1549 | 164 | cn->used = 0; |
3ceadcf6 ON |
165 | cn->corename = NULL; |
166 | if (expand_corename(cn, core_name_size)) | |
10c28d93 | 167 | return -ENOMEM; |
888ffc59 ON |
168 | cn->corename[0] = '\0'; |
169 | ||
170 | if (ispipe) | |
171 | ++pat_ptr; | |
10c28d93 AK |
172 | |
173 | /* Repeat as long as we have more pattern to process and more output | |
174 | space */ | |
175 | while (*pat_ptr) { | |
176 | if (*pat_ptr != '%') { | |
10c28d93 AK |
177 | err = cn_printf(cn, "%c", *pat_ptr++); |
178 | } else { | |
179 | switch (*++pat_ptr) { | |
180 | /* single % at the end, drop that */ | |
181 | case 0: | |
182 | goto out; | |
183 | /* Double percent, output one percent */ | |
184 | case '%': | |
185 | err = cn_printf(cn, "%c", '%'); | |
186 | break; | |
187 | /* pid */ | |
188 | case 'p': | |
189 | pid_in_pattern = 1; | |
190 | err = cn_printf(cn, "%d", | |
191 | task_tgid_vnr(current)); | |
192 | break; | |
65aafb1e SG |
193 | /* global pid */ |
194 | case 'P': | |
195 | err = cn_printf(cn, "%d", | |
196 | task_tgid_nr(current)); | |
197 | break; | |
10c28d93 AK |
198 | /* uid */ |
199 | case 'u': | |
200 | err = cn_printf(cn, "%d", cred->uid); | |
201 | break; | |
202 | /* gid */ | |
203 | case 'g': | |
204 | err = cn_printf(cn, "%d", cred->gid); | |
205 | break; | |
12a2b4b2 ON |
206 | case 'd': |
207 | err = cn_printf(cn, "%d", | |
208 | __get_dumpable(cprm->mm_flags)); | |
209 | break; | |
10c28d93 AK |
210 | /* signal that caused the coredump */ |
211 | case 's': | |
5ab1c309 | 212 | err = cn_printf(cn, "%ld", cprm->siginfo->si_signo); |
10c28d93 AK |
213 | break; |
214 | /* UNIX time of coredump */ | |
215 | case 't': { | |
216 | struct timeval tv; | |
217 | do_gettimeofday(&tv); | |
218 | err = cn_printf(cn, "%lu", tv.tv_sec); | |
219 | break; | |
220 | } | |
221 | /* hostname */ | |
923bed03 | 222 | case 'h': |
10c28d93 | 223 | down_read(&uts_sem); |
923bed03 | 224 | err = cn_esc_printf(cn, "%s", |
10c28d93 AK |
225 | utsname()->nodename); |
226 | up_read(&uts_sem); | |
10c28d93 | 227 | break; |
10c28d93 | 228 | /* executable */ |
923bed03 ON |
229 | case 'e': |
230 | err = cn_esc_printf(cn, "%s", current->comm); | |
10c28d93 | 231 | break; |
10c28d93 AK |
232 | case 'E': |
233 | err = cn_print_exe_file(cn); | |
234 | break; | |
235 | /* core limit size */ | |
236 | case 'c': | |
237 | err = cn_printf(cn, "%lu", | |
238 | rlimit(RLIMIT_CORE)); | |
239 | break; | |
240 | default: | |
241 | break; | |
242 | } | |
243 | ++pat_ptr; | |
244 | } | |
245 | ||
246 | if (err) | |
247 | return err; | |
248 | } | |
249 | ||
888ffc59 | 250 | out: |
10c28d93 AK |
251 | /* Backward compatibility with core_uses_pid: |
252 | * | |
253 | * If core_pattern does not include a %p (as is the default) | |
254 | * and core_uses_pid is set, then .%pid will be appended to | |
255 | * the filename. Do not do this for piped commands. */ | |
256 | if (!ispipe && !pid_in_pattern && core_uses_pid) { | |
257 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); | |
258 | if (err) | |
259 | return err; | |
260 | } | |
10c28d93 AK |
261 | return ispipe; |
262 | } | |
263 | ||
264 | static int zap_process(struct task_struct *start, int exit_code) | |
265 | { | |
266 | struct task_struct *t; | |
267 | int nr = 0; | |
268 | ||
10c28d93 AK |
269 | start->signal->group_exit_code = exit_code; |
270 | start->signal->group_stop_count = 0; | |
271 | ||
272 | t = start; | |
273 | do { | |
274 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); | |
275 | if (t != current && t->mm) { | |
276 | sigaddset(&t->pending.signal, SIGKILL); | |
277 | signal_wake_up(t, 1); | |
278 | nr++; | |
279 | } | |
280 | } while_each_thread(start, t); | |
281 | ||
282 | return nr; | |
283 | } | |
284 | ||
403bad72 ON |
285 | static int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
286 | struct core_state *core_state, int exit_code) | |
10c28d93 AK |
287 | { |
288 | struct task_struct *g, *p; | |
289 | unsigned long flags; | |
290 | int nr = -EAGAIN; | |
291 | ||
292 | spin_lock_irq(&tsk->sighand->siglock); | |
293 | if (!signal_group_exit(tsk->signal)) { | |
294 | mm->core_state = core_state; | |
295 | nr = zap_process(tsk, exit_code); | |
6cd8f0ac | 296 | tsk->signal->group_exit_task = tsk; |
403bad72 | 297 | /* ignore all signals except SIGKILL, see prepare_signal() */ |
6cd8f0ac | 298 | tsk->signal->flags = SIGNAL_GROUP_COREDUMP; |
403bad72 | 299 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING); |
10c28d93 AK |
300 | } |
301 | spin_unlock_irq(&tsk->sighand->siglock); | |
302 | if (unlikely(nr < 0)) | |
303 | return nr; | |
304 | ||
079148b9 | 305 | tsk->flags = PF_DUMPCORE; |
10c28d93 AK |
306 | if (atomic_read(&mm->mm_users) == nr + 1) |
307 | goto done; | |
308 | /* | |
309 | * We should find and kill all tasks which use this mm, and we should | |
310 | * count them correctly into ->nr_threads. We don't take tasklist | |
311 | * lock, but this is safe wrt: | |
312 | * | |
313 | * fork: | |
314 | * None of sub-threads can fork after zap_process(leader). All | |
315 | * processes which were created before this point should be | |
316 | * visible to zap_threads() because copy_process() adds the new | |
317 | * process to the tail of init_task.tasks list, and lock/unlock | |
318 | * of ->siglock provides a memory barrier. | |
319 | * | |
320 | * do_exit: | |
321 | * The caller holds mm->mmap_sem. This means that the task which | |
322 | * uses this mm can't pass exit_mm(), so it can't exit or clear | |
323 | * its ->mm. | |
324 | * | |
325 | * de_thread: | |
326 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
327 | * we must see either old or new leader, this does not matter. | |
328 | * However, it can change p->sighand, so lock_task_sighand(p) | |
329 | * must be used. Since p->mm != NULL and we hold ->mmap_sem | |
330 | * it can't fail. | |
331 | * | |
332 | * Note also that "g" can be the old leader with ->mm == NULL | |
333 | * and already unhashed and thus removed from ->thread_group. | |
334 | * This is OK, __unhash_process()->list_del_rcu() does not | |
335 | * clear the ->next pointer, we will find the new leader via | |
336 | * next_thread(). | |
337 | */ | |
338 | rcu_read_lock(); | |
339 | for_each_process(g) { | |
340 | if (g == tsk->group_leader) | |
341 | continue; | |
342 | if (g->flags & PF_KTHREAD) | |
343 | continue; | |
344 | p = g; | |
345 | do { | |
346 | if (p->mm) { | |
347 | if (unlikely(p->mm == mm)) { | |
348 | lock_task_sighand(p, &flags); | |
349 | nr += zap_process(p, exit_code); | |
6cd8f0ac | 350 | p->signal->flags = SIGNAL_GROUP_EXIT; |
10c28d93 AK |
351 | unlock_task_sighand(p, &flags); |
352 | } | |
353 | break; | |
354 | } | |
355 | } while_each_thread(g, p); | |
356 | } | |
357 | rcu_read_unlock(); | |
358 | done: | |
359 | atomic_set(&core_state->nr_threads, nr); | |
360 | return nr; | |
361 | } | |
362 | ||
363 | static int coredump_wait(int exit_code, struct core_state *core_state) | |
364 | { | |
365 | struct task_struct *tsk = current; | |
366 | struct mm_struct *mm = tsk->mm; | |
367 | int core_waiters = -EBUSY; | |
368 | ||
369 | init_completion(&core_state->startup); | |
370 | core_state->dumper.task = tsk; | |
371 | core_state->dumper.next = NULL; | |
372 | ||
373 | down_write(&mm->mmap_sem); | |
374 | if (!mm->core_state) | |
375 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); | |
376 | up_write(&mm->mmap_sem); | |
377 | ||
378 | if (core_waiters > 0) { | |
379 | struct core_thread *ptr; | |
380 | ||
381 | wait_for_completion(&core_state->startup); | |
382 | /* | |
383 | * Wait for all the threads to become inactive, so that | |
384 | * all the thread context (extended register state, like | |
385 | * fpu etc) gets copied to the memory. | |
386 | */ | |
387 | ptr = core_state->dumper.next; | |
388 | while (ptr != NULL) { | |
389 | wait_task_inactive(ptr->task, 0); | |
390 | ptr = ptr->next; | |
391 | } | |
392 | } | |
393 | ||
394 | return core_waiters; | |
395 | } | |
396 | ||
acdedd99 | 397 | static void coredump_finish(struct mm_struct *mm, bool core_dumped) |
10c28d93 AK |
398 | { |
399 | struct core_thread *curr, *next; | |
400 | struct task_struct *task; | |
401 | ||
6cd8f0ac | 402 | spin_lock_irq(¤t->sighand->siglock); |
acdedd99 ON |
403 | if (core_dumped && !__fatal_signal_pending(current)) |
404 | current->signal->group_exit_code |= 0x80; | |
6cd8f0ac ON |
405 | current->signal->group_exit_task = NULL; |
406 | current->signal->flags = SIGNAL_GROUP_EXIT; | |
407 | spin_unlock_irq(¤t->sighand->siglock); | |
408 | ||
10c28d93 AK |
409 | next = mm->core_state->dumper.next; |
410 | while ((curr = next) != NULL) { | |
411 | next = curr->next; | |
412 | task = curr->task; | |
413 | /* | |
414 | * see exit_mm(), curr->task must not see | |
415 | * ->task == NULL before we read ->next. | |
416 | */ | |
417 | smp_mb(); | |
418 | curr->task = NULL; | |
419 | wake_up_process(task); | |
420 | } | |
421 | ||
422 | mm->core_state = NULL; | |
423 | } | |
424 | ||
528f827e ON |
425 | static bool dump_interrupted(void) |
426 | { | |
427 | /* | |
428 | * SIGKILL or freezing() interrupt the coredumping. Perhaps we | |
429 | * can do try_to_freeze() and check __fatal_signal_pending(), | |
430 | * but then we need to teach dump_write() to restart and clear | |
431 | * TIF_SIGPENDING. | |
432 | */ | |
433 | return signal_pending(current); | |
434 | } | |
435 | ||
10c28d93 AK |
436 | static void wait_for_dump_helpers(struct file *file) |
437 | { | |
de32ec4c | 438 | struct pipe_inode_info *pipe = file->private_data; |
10c28d93 AK |
439 | |
440 | pipe_lock(pipe); | |
441 | pipe->readers++; | |
442 | pipe->writers--; | |
dc7ee2aa ON |
443 | wake_up_interruptible_sync(&pipe->wait); |
444 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); | |
445 | pipe_unlock(pipe); | |
10c28d93 | 446 | |
dc7ee2aa ON |
447 | /* |
448 | * We actually want wait_event_freezable() but then we need | |
449 | * to clear TIF_SIGPENDING and improve dump_interrupted(). | |
450 | */ | |
451 | wait_event_interruptible(pipe->wait, pipe->readers == 1); | |
10c28d93 | 452 | |
dc7ee2aa | 453 | pipe_lock(pipe); |
10c28d93 AK |
454 | pipe->readers--; |
455 | pipe->writers++; | |
456 | pipe_unlock(pipe); | |
10c28d93 AK |
457 | } |
458 | ||
459 | /* | |
460 | * umh_pipe_setup | |
461 | * helper function to customize the process used | |
462 | * to collect the core in userspace. Specifically | |
463 | * it sets up a pipe and installs it as fd 0 (stdin) | |
464 | * for the process. Returns 0 on success, or | |
465 | * PTR_ERR on failure. | |
466 | * Note that it also sets the core limit to 1. This | |
467 | * is a special value that we use to trap recursive | |
468 | * core dumps | |
469 | */ | |
470 | static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) | |
471 | { | |
472 | struct file *files[2]; | |
473 | struct coredump_params *cp = (struct coredump_params *)info->data; | |
474 | int err = create_pipe_files(files, 0); | |
475 | if (err) | |
476 | return err; | |
477 | ||
478 | cp->file = files[1]; | |
479 | ||
45525b26 AV |
480 | err = replace_fd(0, files[0], 0); |
481 | fput(files[0]); | |
10c28d93 AK |
482 | /* and disallow core files too */ |
483 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; | |
484 | ||
45525b26 | 485 | return err; |
10c28d93 AK |
486 | } |
487 | ||
ec57941e | 488 | void do_coredump(const siginfo_t *siginfo) |
10c28d93 AK |
489 | { |
490 | struct core_state core_state; | |
491 | struct core_name cn; | |
492 | struct mm_struct *mm = current->mm; | |
493 | struct linux_binfmt * binfmt; | |
494 | const struct cred *old_cred; | |
495 | struct cred *cred; | |
496 | int retval = 0; | |
497 | int flag = 0; | |
498 | int ispipe; | |
499 | struct files_struct *displaced; | |
500 | bool need_nonrelative = false; | |
acdedd99 | 501 | bool core_dumped = false; |
10c28d93 AK |
502 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
503 | struct coredump_params cprm = { | |
5ab1c309 | 504 | .siginfo = siginfo, |
541880d9 | 505 | .regs = signal_pt_regs(), |
10c28d93 AK |
506 | .limit = rlimit(RLIMIT_CORE), |
507 | /* | |
508 | * We must use the same mm->flags while dumping core to avoid | |
509 | * inconsistency of bit flags, since this flag is not protected | |
510 | * by any locks. | |
511 | */ | |
512 | .mm_flags = mm->flags, | |
513 | }; | |
514 | ||
5ab1c309 | 515 | audit_core_dumps(siginfo->si_signo); |
10c28d93 AK |
516 | |
517 | binfmt = mm->binfmt; | |
518 | if (!binfmt || !binfmt->core_dump) | |
519 | goto fail; | |
520 | if (!__get_dumpable(cprm.mm_flags)) | |
521 | goto fail; | |
522 | ||
523 | cred = prepare_creds(); | |
524 | if (!cred) | |
525 | goto fail; | |
526 | /* | |
527 | * We cannot trust fsuid as being the "true" uid of the process | |
528 | * nor do we know its entire history. We only know it was tainted | |
529 | * so we dump it as root in mode 2, and only into a controlled | |
530 | * environment (pipe handler or fully qualified path). | |
531 | */ | |
e579d2c2 | 532 | if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) { |
10c28d93 AK |
533 | /* Setuid core dump mode */ |
534 | flag = O_EXCL; /* Stop rewrite attacks */ | |
535 | cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ | |
536 | need_nonrelative = true; | |
537 | } | |
538 | ||
5ab1c309 | 539 | retval = coredump_wait(siginfo->si_signo, &core_state); |
10c28d93 AK |
540 | if (retval < 0) |
541 | goto fail_creds; | |
542 | ||
543 | old_cred = override_creds(cred); | |
544 | ||
12a2b4b2 | 545 | ispipe = format_corename(&cn, &cprm); |
10c28d93 | 546 | |
fb96c475 | 547 | if (ispipe) { |
10c28d93 AK |
548 | int dump_count; |
549 | char **helper_argv; | |
907ed132 | 550 | struct subprocess_info *sub_info; |
10c28d93 AK |
551 | |
552 | if (ispipe < 0) { | |
553 | printk(KERN_WARNING "format_corename failed\n"); | |
554 | printk(KERN_WARNING "Aborting core\n"); | |
e7fd1549 | 555 | goto fail_unlock; |
10c28d93 AK |
556 | } |
557 | ||
558 | if (cprm.limit == 1) { | |
559 | /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. | |
560 | * | |
561 | * Normally core limits are irrelevant to pipes, since | |
562 | * we're not writing to the file system, but we use | |
563 | * cprm.limit of 1 here as a speacial value, this is a | |
564 | * consistent way to catch recursive crashes. | |
565 | * We can still crash if the core_pattern binary sets | |
566 | * RLIM_CORE = !1, but it runs as root, and can do | |
567 | * lots of stupid things. | |
568 | * | |
569 | * Note that we use task_tgid_vnr here to grab the pid | |
570 | * of the process group leader. That way we get the | |
571 | * right pid if a thread in a multi-threaded | |
572 | * core_pattern process dies. | |
573 | */ | |
574 | printk(KERN_WARNING | |
575 | "Process %d(%s) has RLIMIT_CORE set to 1\n", | |
576 | task_tgid_vnr(current), current->comm); | |
577 | printk(KERN_WARNING "Aborting core\n"); | |
578 | goto fail_unlock; | |
579 | } | |
580 | cprm.limit = RLIM_INFINITY; | |
581 | ||
582 | dump_count = atomic_inc_return(&core_dump_count); | |
583 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { | |
584 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", | |
585 | task_tgid_vnr(current), current->comm); | |
586 | printk(KERN_WARNING "Skipping core dump\n"); | |
587 | goto fail_dropcount; | |
588 | } | |
589 | ||
888ffc59 | 590 | helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL); |
10c28d93 AK |
591 | if (!helper_argv) { |
592 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
593 | __func__); | |
594 | goto fail_dropcount; | |
595 | } | |
596 | ||
907ed132 LDM |
597 | retval = -ENOMEM; |
598 | sub_info = call_usermodehelper_setup(helper_argv[0], | |
599 | helper_argv, NULL, GFP_KERNEL, | |
600 | umh_pipe_setup, NULL, &cprm); | |
601 | if (sub_info) | |
602 | retval = call_usermodehelper_exec(sub_info, | |
603 | UMH_WAIT_EXEC); | |
604 | ||
10c28d93 AK |
605 | argv_free(helper_argv); |
606 | if (retval) { | |
888ffc59 | 607 | printk(KERN_INFO "Core dump to |%s pipe failed\n", |
10c28d93 AK |
608 | cn.corename); |
609 | goto close_fail; | |
fb96c475 | 610 | } |
10c28d93 AK |
611 | } else { |
612 | struct inode *inode; | |
613 | ||
614 | if (cprm.limit < binfmt->min_coredump) | |
615 | goto fail_unlock; | |
616 | ||
617 | if (need_nonrelative && cn.corename[0] != '/') { | |
618 | printk(KERN_WARNING "Pid %d(%s) can only dump core "\ | |
619 | "to fully qualified path!\n", | |
620 | task_tgid_vnr(current), current->comm); | |
621 | printk(KERN_WARNING "Skipping core dump\n"); | |
622 | goto fail_unlock; | |
623 | } | |
624 | ||
625 | cprm.file = filp_open(cn.corename, | |
626 | O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag, | |
627 | 0600); | |
628 | if (IS_ERR(cprm.file)) | |
629 | goto fail_unlock; | |
630 | ||
496ad9aa | 631 | inode = file_inode(cprm.file); |
10c28d93 AK |
632 | if (inode->i_nlink > 1) |
633 | goto close_fail; | |
634 | if (d_unhashed(cprm.file->f_path.dentry)) | |
635 | goto close_fail; | |
636 | /* | |
637 | * AK: actually i see no reason to not allow this for named | |
638 | * pipes etc, but keep the previous behaviour for now. | |
639 | */ | |
640 | if (!S_ISREG(inode->i_mode)) | |
641 | goto close_fail; | |
642 | /* | |
643 | * Dont allow local users get cute and trick others to coredump | |
644 | * into their pre-created files. | |
645 | */ | |
646 | if (!uid_eq(inode->i_uid, current_fsuid())) | |
647 | goto close_fail; | |
72c2d531 | 648 | if (!cprm.file->f_op->write) |
10c28d93 AK |
649 | goto close_fail; |
650 | if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file)) | |
651 | goto close_fail; | |
652 | } | |
653 | ||
654 | /* get us an unshared descriptor table; almost always a no-op */ | |
655 | retval = unshare_files(&displaced); | |
656 | if (retval) | |
657 | goto close_fail; | |
658 | if (displaced) | |
659 | put_files_struct(displaced); | |
e86d35c3 AV |
660 | if (!dump_interrupted()) { |
661 | file_start_write(cprm.file); | |
662 | core_dumped = binfmt->core_dump(&cprm); | |
663 | file_end_write(cprm.file); | |
664 | } | |
10c28d93 AK |
665 | if (ispipe && core_pipe_limit) |
666 | wait_for_dump_helpers(cprm.file); | |
667 | close_fail: | |
668 | if (cprm.file) | |
669 | filp_close(cprm.file, NULL); | |
670 | fail_dropcount: | |
671 | if (ispipe) | |
672 | atomic_dec(&core_dump_count); | |
673 | fail_unlock: | |
674 | kfree(cn.corename); | |
acdedd99 | 675 | coredump_finish(mm, core_dumped); |
10c28d93 AK |
676 | revert_creds(old_cred); |
677 | fail_creds: | |
678 | put_cred(cred); | |
679 | fail: | |
680 | return; | |
681 | } | |
682 | ||
683 | /* | |
684 | * Core dumping helper functions. These are the only things you should | |
685 | * do on a core-file: use only these functions to write out all the | |
686 | * necessary info. | |
687 | */ | |
ecc8c772 AV |
688 | int dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
689 | { | |
690 | struct file *file = cprm->file; | |
2507a4fb AV |
691 | loff_t pos = file->f_pos; |
692 | ssize_t n; | |
ecc8c772 AV |
693 | if (cprm->written + nr > cprm->limit) |
694 | return 0; | |
2507a4fb AV |
695 | while (nr) { |
696 | if (dump_interrupted()) | |
697 | return 0; | |
52da40ae | 698 | n = __kernel_write(file, addr, nr, &pos); |
2507a4fb AV |
699 | if (n <= 0) |
700 | return 0; | |
701 | file->f_pos = pos; | |
702 | cprm->written += n; | |
703 | nr -= n; | |
704 | } | |
ecc8c772 AV |
705 | return 1; |
706 | } | |
707 | EXPORT_SYMBOL(dump_emit); | |
708 | ||
9b56d543 | 709 | int dump_skip(struct coredump_params *cprm, size_t nr) |
10c28d93 | 710 | { |
9b56d543 AV |
711 | static char zeroes[PAGE_SIZE]; |
712 | struct file *file = cprm->file; | |
10c28d93 | 713 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { |
9b56d543 AV |
714 | if (cprm->written + nr > cprm->limit) |
715 | return 0; | |
528f827e | 716 | if (dump_interrupted() || |
9b56d543 | 717 | file->f_op->llseek(file, nr, SEEK_CUR) < 0) |
10c28d93 | 718 | return 0; |
9b56d543 AV |
719 | cprm->written += nr; |
720 | return 1; | |
10c28d93 | 721 | } else { |
9b56d543 AV |
722 | while (nr > PAGE_SIZE) { |
723 | if (!dump_emit(cprm, zeroes, PAGE_SIZE)) | |
724 | return 0; | |
725 | nr -= PAGE_SIZE; | |
10c28d93 | 726 | } |
9b56d543 | 727 | return dump_emit(cprm, zeroes, nr); |
10c28d93 | 728 | } |
10c28d93 | 729 | } |
9b56d543 | 730 | EXPORT_SYMBOL(dump_skip); |
22a8cb82 AV |
731 | |
732 | int dump_align(struct coredump_params *cprm, int align) | |
733 | { | |
734 | unsigned mod = cprm->written & (align - 1); | |
735 | if (align & (align - 1)) | |
db51242d AV |
736 | return 0; |
737 | return mod ? dump_skip(cprm, align - mod) : 1; | |
22a8cb82 AV |
738 | } |
739 | EXPORT_SYMBOL(dump_align); |