blob: 9bdeca12ae0e388ecda010964c5209313cb363a9 [file] [log] [blame]
Alex Kelly10c28d92012-09-26 21:52:08 -04001#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>
Alex Kelly179899f2012-10-04 17:15:24 -070017#include <linux/coredump.h>
Alex Kelly10c28d92012-09-26 21:52:08 -040018#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"
Alex Kelly179899f2012-10-04 17:15:24 -070043#include "coredump.h"
Alex Kelly10c28d92012-09-26 21:52:08 -040044
45#include <trace/events/sched.h>
46
47int core_uses_pid;
Alex Kelly10c28d92012-09-26 21:52:08 -040048unsigned int core_pipe_limit;
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070049char core_pattern[CORENAME_MAX_SIZE] = "core";
50static int core_name_size = CORENAME_MAX_SIZE;
Alex Kelly10c28d92012-09-26 21:52:08 -040051
52struct core_name {
53 char *corename;
54 int used, size;
55};
Alex Kelly10c28d92012-09-26 21:52:08 -040056
57/* The maximal length of core_pattern is also specified in sysctl.c */
58
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070059static int expand_corename(struct core_name *cn, int size)
Alex Kelly10c28d92012-09-26 21:52:08 -040060{
Oleg Nesterove7fd1542013-07-03 15:08:16 -070061 char *corename = krealloc(cn->corename, size, GFP_KERNEL);
Alex Kelly10c28d92012-09-26 21:52:08 -040062
Oleg Nesterove7fd1542013-07-03 15:08:16 -070063 if (!corename)
Alex Kelly10c28d92012-09-26 21:52:08 -040064 return -ENOMEM;
Alex Kelly10c28d92012-09-26 21:52:08 -040065
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070066 if (size > core_name_size) /* racy but harmless */
67 core_name_size = size;
68
69 cn->size = ksize(corename);
Oleg Nesterove7fd1542013-07-03 15:08:16 -070070 cn->corename = corename;
Alex Kelly10c28d92012-09-26 21:52:08 -040071 return 0;
72}
73
Oleg Nesterovbc03c692013-07-03 15:08:17 -070074static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
Alex Kelly10c28d92012-09-26 21:52:08 -040075{
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070076 int free, need;
Alex Kelly10c28d92012-09-26 21:52:08 -040077
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070078again:
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 }
Alex Kelly10c28d92012-09-26 21:52:08 -040085
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070086 if (!expand_corename(cn, cn->size + need - free + 1))
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070087 goto again;
Alex Kelly10c28d92012-09-26 21:52:08 -040088
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070089 return -ENOMEM;
Alex Kelly10c28d92012-09-26 21:52:08 -040090}
91
Oleg Nesterovbc03c692013-07-03 15:08:17 -070092static 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
Oleg Nesterov923bed032013-07-03 15:08:20 -0700104static int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
Alex Kelly10c28d92012-09-26 21:52:08 -0400105{
Oleg Nesterov923bed032013-07-03 15:08:20 -0700106 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;
Alex Kelly10c28d92012-09-26 21:52:08 -0400119}
120
121static 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);
Oleg Nesterov923bed032013-07-03 15:08:20 -0700128 if (!exe_file)
129 return cn_esc_printf(cn, "%s (path unknown)", current->comm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400130
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
Oleg Nesterov923bed032013-07-03 15:08:20 -0700143 ret = cn_esc_printf(cn, "%s", path);
Alex Kelly10c28d92012-09-26 21:52:08 -0400144
145free_buf:
146 kfree(pathbuf);
147put_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 */
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700156static int format_corename(struct core_name *cn, struct coredump_params *cprm)
Alex Kelly10c28d92012-09-26 21:52:08 -0400157{
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
Oleg Nesterove7fd1542013-07-03 15:08:16 -0700164 cn->used = 0;
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -0700165 cn->corename = NULL;
166 if (expand_corename(cn, core_name_size))
Alex Kelly10c28d92012-09-26 21:52:08 -0400167 return -ENOMEM;
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700168 cn->corename[0] = '\0';
169
170 if (ispipe)
171 ++pat_ptr;
Alex Kelly10c28d92012-09-26 21:52:08 -0400172
173 /* Repeat as long as we have more pattern to process and more output
174 space */
175 while (*pat_ptr) {
176 if (*pat_ptr != '%') {
Alex Kelly10c28d92012-09-26 21:52:08 -0400177 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;
Stéphane Graber65aafb12013-09-11 14:24:32 -0700193 /* global pid */
194 case 'P':
195 err = cn_printf(cn, "%d",
196 task_tgid_nr(current));
197 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400198 /* 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;
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700206 case 'd':
207 err = cn_printf(cn, "%d",
208 __get_dumpable(cprm->mm_flags));
209 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400210 /* signal that caused the coredump */
211 case 's':
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700212 err = cn_printf(cn, "%ld", cprm->siginfo->si_signo);
Alex Kelly10c28d92012-09-26 21:52:08 -0400213 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 */
Oleg Nesterov923bed032013-07-03 15:08:20 -0700222 case 'h':
Alex Kelly10c28d92012-09-26 21:52:08 -0400223 down_read(&uts_sem);
Oleg Nesterov923bed032013-07-03 15:08:20 -0700224 err = cn_esc_printf(cn, "%s",
Alex Kelly10c28d92012-09-26 21:52:08 -0400225 utsname()->nodename);
226 up_read(&uts_sem);
Alex Kelly10c28d92012-09-26 21:52:08 -0400227 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400228 /* executable */
Oleg Nesterov923bed032013-07-03 15:08:20 -0700229 case 'e':
230 err = cn_esc_printf(cn, "%s", current->comm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400231 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400232 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
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700250out:
Alex Kelly10c28d92012-09-26 21:52:08 -0400251 /* 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 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400261 return ispipe;
262}
263
264static int zap_process(struct task_struct *start, int exit_code)
265{
266 struct task_struct *t;
267 int nr = 0;
268
Alex Kelly10c28d92012-09-26 21:52:08 -0400269 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
Oleg Nesterov403bad72013-04-30 15:28:10 -0700285static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
286 struct core_state *core_state, int exit_code)
Alex Kelly10c28d92012-09-26 21:52:08 -0400287{
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);
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700296 tsk->signal->group_exit_task = tsk;
Oleg Nesterov403bad72013-04-30 15:28:10 -0700297 /* ignore all signals except SIGKILL, see prepare_signal() */
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700298 tsk->signal->flags = SIGNAL_GROUP_COREDUMP;
Oleg Nesterov403bad72013-04-30 15:28:10 -0700299 clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
Alex Kelly10c28d92012-09-26 21:52:08 -0400300 }
301 spin_unlock_irq(&tsk->sighand->siglock);
302 if (unlikely(nr < 0))
303 return nr;
304
Oleg Nesterov079148b2013-04-30 15:28:16 -0700305 tsk->flags = PF_DUMPCORE;
Alex Kelly10c28d92012-09-26 21:52:08 -0400306 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, &current->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);
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700350 p->signal->flags = SIGNAL_GROUP_EXIT;
Alex Kelly10c28d92012-09-26 21:52:08 -0400351 unlock_task_sighand(p, &flags);
352 }
353 break;
354 }
355 } while_each_thread(g, p);
356 }
357 rcu_read_unlock();
358done:
359 atomic_set(&core_state->nr_threads, nr);
360 return nr;
361}
362
363static 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
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700397static void coredump_finish(struct mm_struct *mm, bool core_dumped)
Alex Kelly10c28d92012-09-26 21:52:08 -0400398{
399 struct core_thread *curr, *next;
400 struct task_struct *task;
401
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700402 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700403 if (core_dumped && !__fatal_signal_pending(current))
404 current->signal->group_exit_code |= 0x80;
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700405 current->signal->group_exit_task = NULL;
406 current->signal->flags = SIGNAL_GROUP_EXIT;
407 spin_unlock_irq(&current->sighand->siglock);
408
Alex Kelly10c28d92012-09-26 21:52:08 -0400409 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
Oleg Nesterov528f8272013-04-30 15:28:15 -0700425static 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
Alex Kelly10c28d92012-09-26 21:52:08 -0400436static void wait_for_dump_helpers(struct file *file)
437{
Al Virode32ec42013-03-21 11:16:56 -0400438 struct pipe_inode_info *pipe = file->private_data;
Alex Kelly10c28d92012-09-26 21:52:08 -0400439
440 pipe_lock(pipe);
441 pipe->readers++;
442 pipe->writers--;
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700443 wake_up_interruptible_sync(&pipe->wait);
444 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
445 pipe_unlock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400446
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700447 /*
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);
Alex Kelly10c28d92012-09-26 21:52:08 -0400452
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700453 pipe_lock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400454 pipe->readers--;
455 pipe->writers++;
456 pipe_unlock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400457}
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 */
470static 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
Al Viro45525b22012-10-16 13:30:07 -0400480 err = replace_fd(0, files[0], 0);
481 fput(files[0]);
Alex Kelly10c28d92012-09-26 21:52:08 -0400482 /* and disallow core files too */
483 current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
484
Al Viro45525b22012-10-16 13:30:07 -0400485 return err;
Alex Kelly10c28d92012-09-26 21:52:08 -0400486}
487
Al Viro541880d2012-11-05 13:11:26 -0500488void do_coredump(siginfo_t *siginfo)
Alex Kelly10c28d92012-09-26 21:52:08 -0400489{
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;
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700501 bool core_dumped = false;
Alex Kelly10c28d92012-09-26 21:52:08 -0400502 static atomic_t core_dump_count = ATOMIC_INIT(0);
503 struct coredump_params cprm = {
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700504 .siginfo = siginfo,
Al Viro541880d2012-11-05 13:11:26 -0500505 .regs = signal_pt_regs(),
Alex Kelly10c28d92012-09-26 21:52:08 -0400506 .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
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700515 audit_core_dumps(siginfo->si_signo);
Alex Kelly10c28d92012-09-26 21:52:08 -0400516
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 */
Kees Cooke579d2c2013-02-27 17:03:15 -0800532 if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) {
Alex Kelly10c28d92012-09-26 21:52:08 -0400533 /* 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
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700539 retval = coredump_wait(siginfo->si_signo, &core_state);
Alex Kelly10c28d92012-09-26 21:52:08 -0400540 if (retval < 0)
541 goto fail_creds;
542
543 old_cred = override_creds(cred);
544
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700545 ispipe = format_corename(&cn, &cprm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400546
Lucas De Marchifb96c472013-04-30 15:28:06 -0700547 if (ispipe) {
Alex Kelly10c28d92012-09-26 21:52:08 -0400548 int dump_count;
549 char **helper_argv;
Lucas De Marchi907ed132013-04-30 15:28:07 -0700550 struct subprocess_info *sub_info;
Alex Kelly10c28d92012-09-26 21:52:08 -0400551
552 if (ispipe < 0) {
553 printk(KERN_WARNING "format_corename failed\n");
554 printk(KERN_WARNING "Aborting core\n");
Oleg Nesterove7fd1542013-07-03 15:08:16 -0700555 goto fail_unlock;
Alex Kelly10c28d92012-09-26 21:52:08 -0400556 }
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
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700590 helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
Alex Kelly10c28d92012-09-26 21:52:08 -0400591 if (!helper_argv) {
592 printk(KERN_WARNING "%s failed to allocate memory\n",
593 __func__);
594 goto fail_dropcount;
595 }
596
Lucas De Marchi907ed132013-04-30 15:28:07 -0700597 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
Alex Kelly10c28d92012-09-26 21:52:08 -0400605 argv_free(helper_argv);
606 if (retval) {
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700607 printk(KERN_INFO "Core dump to |%s pipe failed\n",
Alex Kelly10c28d92012-09-26 21:52:08 -0400608 cn.corename);
609 goto close_fail;
Lucas De Marchifb96c472013-04-30 15:28:06 -0700610 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400611 } 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
Al Viro496ad9a2013-01-23 17:07:38 -0500631 inode = file_inode(cprm.file);
Alex Kelly10c28d92012-09-26 21:52:08 -0400632 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;
648 if (!cprm.file->f_op || !cprm.file->f_op->write)
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);
Al Viroe86d35c2013-05-04 14:45:54 -0400660 if (!dump_interrupted()) {
661 file_start_write(cprm.file);
662 core_dumped = binfmt->core_dump(&cprm);
663 file_end_write(cprm.file);
664 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400665 if (ispipe && core_pipe_limit)
666 wait_for_dump_helpers(cprm.file);
667close_fail:
668 if (cprm.file)
669 filp_close(cprm.file, NULL);
670fail_dropcount:
671 if (ispipe)
672 atomic_dec(&core_dump_count);
673fail_unlock:
674 kfree(cn.corename);
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700675 coredump_finish(mm, core_dumped);
Alex Kelly10c28d92012-09-26 21:52:08 -0400676 revert_creds(old_cred);
677fail_creds:
678 put_cred(cred);
679fail:
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 */
688int dump_write(struct file *file, const void *addr, int nr)
689{
Oleg Nesterov528f8272013-04-30 15:28:15 -0700690 return !dump_interrupted() &&
691 access_ok(VERIFY_READ, addr, nr) &&
692 file->f_op->write(file, addr, nr, &file->f_pos) == nr;
Alex Kelly10c28d92012-09-26 21:52:08 -0400693}
694EXPORT_SYMBOL(dump_write);
695
696int dump_seek(struct file *file, loff_t off)
697{
698 int ret = 1;
699
700 if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
Oleg Nesterov528f8272013-04-30 15:28:15 -0700701 if (dump_interrupted() ||
702 file->f_op->llseek(file, off, SEEK_CUR) < 0)
Alex Kelly10c28d92012-09-26 21:52:08 -0400703 return 0;
704 } else {
705 char *buf = (char *)get_zeroed_page(GFP_KERNEL);
706
707 if (!buf)
708 return 0;
709 while (off > 0) {
710 unsigned long n = off;
711
712 if (n > PAGE_SIZE)
713 n = PAGE_SIZE;
714 if (!dump_write(file, buf, n)) {
715 ret = 0;
716 break;
717 }
718 off -= n;
719 }
720 free_page((unsigned long)buf);
721 }
722 return ret;
723}
724EXPORT_SYMBOL(dump_seek);