blob: b5c86ffd5033420523934c7153080d8cdc605bea [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 Kelly10c28d92012-09-26 21:52:08 -040043
44#include <trace/events/sched.h>
45
46int core_uses_pid;
Alex Kelly10c28d92012-09-26 21:52:08 -040047unsigned int core_pipe_limit;
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070048char core_pattern[CORENAME_MAX_SIZE] = "core";
49static int core_name_size = CORENAME_MAX_SIZE;
Alex Kelly10c28d92012-09-26 21:52:08 -040050
51struct core_name {
52 char *corename;
53 int used, size;
54};
Alex Kelly10c28d92012-09-26 21:52:08 -040055
56/* The maximal length of core_pattern is also specified in sysctl.c */
57
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070058static int expand_corename(struct core_name *cn, int size)
Alex Kelly10c28d92012-09-26 21:52:08 -040059{
Oleg Nesterove7fd1542013-07-03 15:08:16 -070060 char *corename = krealloc(cn->corename, size, GFP_KERNEL);
Alex Kelly10c28d92012-09-26 21:52:08 -040061
Oleg Nesterove7fd1542013-07-03 15:08:16 -070062 if (!corename)
Alex Kelly10c28d92012-09-26 21:52:08 -040063 return -ENOMEM;
Alex Kelly10c28d92012-09-26 21:52:08 -040064
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070065 if (size > core_name_size) /* racy but harmless */
66 core_name_size = size;
67
68 cn->size = ksize(corename);
Oleg Nesterove7fd1542013-07-03 15:08:16 -070069 cn->corename = corename;
Alex Kelly10c28d92012-09-26 21:52:08 -040070 return 0;
71}
72
Oleg Nesterovbc03c692013-07-03 15:08:17 -070073static int cn_vprintf(struct core_name *cn, const char *fmt, va_list arg)
Alex Kelly10c28d92012-09-26 21:52:08 -040074{
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070075 int free, need;
Eric Dumazet404ca802014-04-19 10:15:07 -070076 va_list arg_copy;
Alex Kelly10c28d92012-09-26 21:52:08 -040077
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070078again:
79 free = cn->size - cn->used;
Eric Dumazet404ca802014-04-19 10:15:07 -070080
81 va_copy(arg_copy, arg);
82 need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy);
83 va_end(arg_copy);
84
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070085 if (need < free) {
86 cn->used += need;
87 return 0;
88 }
Alex Kelly10c28d92012-09-26 21:52:08 -040089
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -070090 if (!expand_corename(cn, cn->size + need - free + 1))
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070091 goto again;
Alex Kelly10c28d92012-09-26 21:52:08 -040092
Oleg Nesterov5fe9d8c2013-07-03 15:08:19 -070093 return -ENOMEM;
Alex Kelly10c28d92012-09-26 21:52:08 -040094}
95
Oleg Nesterovbc03c692013-07-03 15:08:17 -070096static int cn_printf(struct core_name *cn, const char *fmt, ...)
97{
98 va_list arg;
99 int ret;
100
101 va_start(arg, fmt);
102 ret = cn_vprintf(cn, fmt, arg);
103 va_end(arg);
104
105 return ret;
106}
107
Oleg Nesterov923bed032013-07-03 15:08:20 -0700108static int cn_esc_printf(struct core_name *cn, const char *fmt, ...)
Alex Kelly10c28d92012-09-26 21:52:08 -0400109{
Oleg Nesterov923bed032013-07-03 15:08:20 -0700110 int cur = cn->used;
111 va_list arg;
112 int ret;
113
114 va_start(arg, fmt);
115 ret = cn_vprintf(cn, fmt, arg);
116 va_end(arg);
117
118 for (; cur < cn->used; ++cur) {
119 if (cn->corename[cur] == '/')
120 cn->corename[cur] = '!';
121 }
122 return ret;
Alex Kelly10c28d92012-09-26 21:52:08 -0400123}
124
125static int cn_print_exe_file(struct core_name *cn)
126{
127 struct file *exe_file;
128 char *pathbuf, *path;
129 int ret;
130
131 exe_file = get_mm_exe_file(current->mm);
Oleg Nesterov923bed032013-07-03 15:08:20 -0700132 if (!exe_file)
133 return cn_esc_printf(cn, "%s (path unknown)", current->comm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400134
135 pathbuf = kmalloc(PATH_MAX, GFP_TEMPORARY);
136 if (!pathbuf) {
137 ret = -ENOMEM;
138 goto put_exe_file;
139 }
140
141 path = d_path(&exe_file->f_path, pathbuf, PATH_MAX);
142 if (IS_ERR(path)) {
143 ret = PTR_ERR(path);
144 goto free_buf;
145 }
146
Oleg Nesterov923bed032013-07-03 15:08:20 -0700147 ret = cn_esc_printf(cn, "%s", path);
Alex Kelly10c28d92012-09-26 21:52:08 -0400148
149free_buf:
150 kfree(pathbuf);
151put_exe_file:
152 fput(exe_file);
153 return ret;
154}
155
156/* format_corename will inspect the pattern parameter, and output a
157 * name into corename, which must have space for at least
158 * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator.
159 */
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700160static int format_corename(struct core_name *cn, struct coredump_params *cprm)
Alex Kelly10c28d92012-09-26 21:52:08 -0400161{
162 const struct cred *cred = current_cred();
163 const char *pat_ptr = core_pattern;
164 int ispipe = (*pat_ptr == '|');
165 int pid_in_pattern = 0;
166 int err = 0;
167
Oleg Nesterove7fd1542013-07-03 15:08:16 -0700168 cn->used = 0;
Oleg Nesterov3ceadcf2013-07-03 15:08:22 -0700169 cn->corename = NULL;
170 if (expand_corename(cn, core_name_size))
Alex Kelly10c28d92012-09-26 21:52:08 -0400171 return -ENOMEM;
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700172 cn->corename[0] = '\0';
173
174 if (ispipe)
175 ++pat_ptr;
Alex Kelly10c28d92012-09-26 21:52:08 -0400176
177 /* Repeat as long as we have more pattern to process and more output
178 space */
179 while (*pat_ptr) {
180 if (*pat_ptr != '%') {
Alex Kelly10c28d92012-09-26 21:52:08 -0400181 err = cn_printf(cn, "%c", *pat_ptr++);
182 } else {
183 switch (*++pat_ptr) {
184 /* single % at the end, drop that */
185 case 0:
186 goto out;
187 /* Double percent, output one percent */
188 case '%':
189 err = cn_printf(cn, "%c", '%');
190 break;
191 /* pid */
192 case 'p':
193 pid_in_pattern = 1;
194 err = cn_printf(cn, "%d",
195 task_tgid_vnr(current));
196 break;
Stéphane Graber65aafb12013-09-11 14:24:32 -0700197 /* global pid */
198 case 'P':
199 err = cn_printf(cn, "%d",
200 task_tgid_nr(current));
201 break;
Oleg Nesterovb03023e2014-10-13 15:53:35 -0700202 case 'i':
203 err = cn_printf(cn, "%d",
204 task_pid_vnr(current));
205 break;
206 case 'I':
207 err = cn_printf(cn, "%d",
208 task_pid_nr(current));
209 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400210 /* uid */
211 case 'u':
212 err = cn_printf(cn, "%d", cred->uid);
213 break;
214 /* gid */
215 case 'g':
216 err = cn_printf(cn, "%d", cred->gid);
217 break;
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700218 case 'd':
219 err = cn_printf(cn, "%d",
220 __get_dumpable(cprm->mm_flags));
221 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400222 /* signal that caused the coredump */
223 case 's':
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700224 err = cn_printf(cn, "%ld", cprm->siginfo->si_signo);
Alex Kelly10c28d92012-09-26 21:52:08 -0400225 break;
226 /* UNIX time of coredump */
227 case 't': {
228 struct timeval tv;
229 do_gettimeofday(&tv);
230 err = cn_printf(cn, "%lu", tv.tv_sec);
231 break;
232 }
233 /* hostname */
Oleg Nesterov923bed032013-07-03 15:08:20 -0700234 case 'h':
Alex Kelly10c28d92012-09-26 21:52:08 -0400235 down_read(&uts_sem);
Oleg Nesterov923bed032013-07-03 15:08:20 -0700236 err = cn_esc_printf(cn, "%s",
Alex Kelly10c28d92012-09-26 21:52:08 -0400237 utsname()->nodename);
238 up_read(&uts_sem);
Alex Kelly10c28d92012-09-26 21:52:08 -0400239 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400240 /* executable */
Oleg Nesterov923bed032013-07-03 15:08:20 -0700241 case 'e':
242 err = cn_esc_printf(cn, "%s", current->comm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400243 break;
Alex Kelly10c28d92012-09-26 21:52:08 -0400244 case 'E':
245 err = cn_print_exe_file(cn);
246 break;
247 /* core limit size */
248 case 'c':
249 err = cn_printf(cn, "%lu",
250 rlimit(RLIMIT_CORE));
251 break;
252 default:
253 break;
254 }
255 ++pat_ptr;
256 }
257
258 if (err)
259 return err;
260 }
261
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700262out:
Alex Kelly10c28d92012-09-26 21:52:08 -0400263 /* Backward compatibility with core_uses_pid:
264 *
265 * If core_pattern does not include a %p (as is the default)
266 * and core_uses_pid is set, then .%pid will be appended to
267 * the filename. Do not do this for piped commands. */
268 if (!ispipe && !pid_in_pattern && core_uses_pid) {
269 err = cn_printf(cn, ".%d", task_tgid_vnr(current));
270 if (err)
271 return err;
272 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400273 return ispipe;
274}
275
276static int zap_process(struct task_struct *start, int exit_code)
277{
278 struct task_struct *t;
279 int nr = 0;
280
Alex Kelly10c28d92012-09-26 21:52:08 -0400281 start->signal->group_exit_code = exit_code;
282 start->signal->group_stop_count = 0;
283
284 t = start;
285 do {
286 task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK);
287 if (t != current && t->mm) {
288 sigaddset(&t->pending.signal, SIGKILL);
289 signal_wake_up(t, 1);
290 nr++;
291 }
292 } while_each_thread(start, t);
293
294 return nr;
295}
296
Oleg Nesterov403bad72013-04-30 15:28:10 -0700297static int zap_threads(struct task_struct *tsk, struct mm_struct *mm,
298 struct core_state *core_state, int exit_code)
Alex Kelly10c28d92012-09-26 21:52:08 -0400299{
300 struct task_struct *g, *p;
301 unsigned long flags;
302 int nr = -EAGAIN;
303
304 spin_lock_irq(&tsk->sighand->siglock);
305 if (!signal_group_exit(tsk->signal)) {
306 mm->core_state = core_state;
307 nr = zap_process(tsk, exit_code);
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700308 tsk->signal->group_exit_task = tsk;
Oleg Nesterov403bad72013-04-30 15:28:10 -0700309 /* ignore all signals except SIGKILL, see prepare_signal() */
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700310 tsk->signal->flags = SIGNAL_GROUP_COREDUMP;
Oleg Nesterov403bad72013-04-30 15:28:10 -0700311 clear_tsk_thread_flag(tsk, TIF_SIGPENDING);
Alex Kelly10c28d92012-09-26 21:52:08 -0400312 }
313 spin_unlock_irq(&tsk->sighand->siglock);
314 if (unlikely(nr < 0))
315 return nr;
316
Silesh C Vaed8adb2014-07-23 13:59:59 -0700317 tsk->flags |= PF_DUMPCORE;
Alex Kelly10c28d92012-09-26 21:52:08 -0400318 if (atomic_read(&mm->mm_users) == nr + 1)
319 goto done;
320 /*
321 * We should find and kill all tasks which use this mm, and we should
322 * count them correctly into ->nr_threads. We don't take tasklist
323 * lock, but this is safe wrt:
324 *
325 * fork:
326 * None of sub-threads can fork after zap_process(leader). All
327 * processes which were created before this point should be
328 * visible to zap_threads() because copy_process() adds the new
329 * process to the tail of init_task.tasks list, and lock/unlock
330 * of ->siglock provides a memory barrier.
331 *
332 * do_exit:
333 * The caller holds mm->mmap_sem. This means that the task which
334 * uses this mm can't pass exit_mm(), so it can't exit or clear
335 * its ->mm.
336 *
337 * de_thread:
338 * It does list_replace_rcu(&leader->tasks, &current->tasks),
339 * we must see either old or new leader, this does not matter.
340 * However, it can change p->sighand, so lock_task_sighand(p)
341 * must be used. Since p->mm != NULL and we hold ->mmap_sem
342 * it can't fail.
343 *
344 * Note also that "g" can be the old leader with ->mm == NULL
345 * and already unhashed and thus removed from ->thread_group.
346 * This is OK, __unhash_process()->list_del_rcu() does not
347 * clear the ->next pointer, we will find the new leader via
348 * next_thread().
349 */
350 rcu_read_lock();
351 for_each_process(g) {
352 if (g == tsk->group_leader)
353 continue;
354 if (g->flags & PF_KTHREAD)
355 continue;
356 p = g;
357 do {
358 if (p->mm) {
359 if (unlikely(p->mm == mm)) {
360 lock_task_sighand(p, &flags);
361 nr += zap_process(p, exit_code);
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700362 p->signal->flags = SIGNAL_GROUP_EXIT;
Alex Kelly10c28d92012-09-26 21:52:08 -0400363 unlock_task_sighand(p, &flags);
364 }
365 break;
366 }
367 } while_each_thread(g, p);
368 }
369 rcu_read_unlock();
370done:
371 atomic_set(&core_state->nr_threads, nr);
372 return nr;
373}
374
375static int coredump_wait(int exit_code, struct core_state *core_state)
376{
377 struct task_struct *tsk = current;
378 struct mm_struct *mm = tsk->mm;
379 int core_waiters = -EBUSY;
380
381 init_completion(&core_state->startup);
382 core_state->dumper.task = tsk;
383 core_state->dumper.next = NULL;
384
385 down_write(&mm->mmap_sem);
386 if (!mm->core_state)
387 core_waiters = zap_threads(tsk, mm, core_state, exit_code);
388 up_write(&mm->mmap_sem);
389
390 if (core_waiters > 0) {
391 struct core_thread *ptr;
392
393 wait_for_completion(&core_state->startup);
394 /*
395 * Wait for all the threads to become inactive, so that
396 * all the thread context (extended register state, like
397 * fpu etc) gets copied to the memory.
398 */
399 ptr = core_state->dumper.next;
400 while (ptr != NULL) {
401 wait_task_inactive(ptr->task, 0);
402 ptr = ptr->next;
403 }
404 }
405
406 return core_waiters;
407}
408
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700409static void coredump_finish(struct mm_struct *mm, bool core_dumped)
Alex Kelly10c28d92012-09-26 21:52:08 -0400410{
411 struct core_thread *curr, *next;
412 struct task_struct *task;
413
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700414 spin_lock_irq(&current->sighand->siglock);
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700415 if (core_dumped && !__fatal_signal_pending(current))
416 current->signal->group_exit_code |= 0x80;
Oleg Nesterov6cd8f0a2013-04-30 15:28:12 -0700417 current->signal->group_exit_task = NULL;
418 current->signal->flags = SIGNAL_GROUP_EXIT;
419 spin_unlock_irq(&current->sighand->siglock);
420
Alex Kelly10c28d92012-09-26 21:52:08 -0400421 next = mm->core_state->dumper.next;
422 while ((curr = next) != NULL) {
423 next = curr->next;
424 task = curr->task;
425 /*
426 * see exit_mm(), curr->task must not see
427 * ->task == NULL before we read ->next.
428 */
429 smp_mb();
430 curr->task = NULL;
431 wake_up_process(task);
432 }
433
434 mm->core_state = NULL;
435}
436
Oleg Nesterov528f8272013-04-30 15:28:15 -0700437static bool dump_interrupted(void)
438{
439 /*
440 * SIGKILL or freezing() interrupt the coredumping. Perhaps we
441 * can do try_to_freeze() and check __fatal_signal_pending(),
442 * but then we need to teach dump_write() to restart and clear
443 * TIF_SIGPENDING.
444 */
445 return signal_pending(current);
446}
447
Alex Kelly10c28d92012-09-26 21:52:08 -0400448static void wait_for_dump_helpers(struct file *file)
449{
Al Virode32ec42013-03-21 11:16:56 -0400450 struct pipe_inode_info *pipe = file->private_data;
Alex Kelly10c28d92012-09-26 21:52:08 -0400451
452 pipe_lock(pipe);
453 pipe->readers++;
454 pipe->writers--;
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700455 wake_up_interruptible_sync(&pipe->wait);
456 kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN);
457 pipe_unlock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400458
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700459 /*
460 * We actually want wait_event_freezable() but then we need
461 * to clear TIF_SIGPENDING and improve dump_interrupted().
462 */
463 wait_event_interruptible(pipe->wait, pipe->readers == 1);
Alex Kelly10c28d92012-09-26 21:52:08 -0400464
Oleg Nesterovdc7ee2a2013-04-30 15:28:17 -0700465 pipe_lock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400466 pipe->readers--;
467 pipe->writers++;
468 pipe_unlock(pipe);
Alex Kelly10c28d92012-09-26 21:52:08 -0400469}
470
471/*
472 * umh_pipe_setup
473 * helper function to customize the process used
474 * to collect the core in userspace. Specifically
475 * it sets up a pipe and installs it as fd 0 (stdin)
476 * for the process. Returns 0 on success, or
477 * PTR_ERR on failure.
478 * Note that it also sets the core limit to 1. This
479 * is a special value that we use to trap recursive
480 * core dumps
481 */
482static int umh_pipe_setup(struct subprocess_info *info, struct cred *new)
483{
484 struct file *files[2];
485 struct coredump_params *cp = (struct coredump_params *)info->data;
486 int err = create_pipe_files(files, 0);
487 if (err)
488 return err;
489
490 cp->file = files[1];
491
Al Viro45525b22012-10-16 13:30:07 -0400492 err = replace_fd(0, files[0], 0);
493 fput(files[0]);
Alex Kelly10c28d92012-09-26 21:52:08 -0400494 /* and disallow core files too */
495 current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1};
496
Al Viro45525b22012-10-16 13:30:07 -0400497 return err;
Alex Kelly10c28d92012-09-26 21:52:08 -0400498}
499
Al Viroec579412013-10-13 17:57:29 -0400500void do_coredump(const siginfo_t *siginfo)
Alex Kelly10c28d92012-09-26 21:52:08 -0400501{
502 struct core_state core_state;
503 struct core_name cn;
504 struct mm_struct *mm = current->mm;
505 struct linux_binfmt * binfmt;
506 const struct cred *old_cred;
507 struct cred *cred;
508 int retval = 0;
509 int flag = 0;
510 int ispipe;
511 struct files_struct *displaced;
512 bool need_nonrelative = false;
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700513 bool core_dumped = false;
Alex Kelly10c28d92012-09-26 21:52:08 -0400514 static atomic_t core_dump_count = ATOMIC_INIT(0);
515 struct coredump_params cprm = {
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700516 .siginfo = siginfo,
Al Viro541880d2012-11-05 13:11:26 -0500517 .regs = signal_pt_regs(),
Alex Kelly10c28d92012-09-26 21:52:08 -0400518 .limit = rlimit(RLIMIT_CORE),
519 /*
520 * We must use the same mm->flags while dumping core to avoid
521 * inconsistency of bit flags, since this flag is not protected
522 * by any locks.
523 */
524 .mm_flags = mm->flags,
525 };
526
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700527 audit_core_dumps(siginfo->si_signo);
Alex Kelly10c28d92012-09-26 21:52:08 -0400528
529 binfmt = mm->binfmt;
530 if (!binfmt || !binfmt->core_dump)
531 goto fail;
532 if (!__get_dumpable(cprm.mm_flags))
533 goto fail;
534
535 cred = prepare_creds();
536 if (!cred)
537 goto fail;
538 /*
539 * We cannot trust fsuid as being the "true" uid of the process
540 * nor do we know its entire history. We only know it was tainted
541 * so we dump it as root in mode 2, and only into a controlled
542 * environment (pipe handler or fully qualified path).
543 */
Kees Cooke579d2c2013-02-27 17:03:15 -0800544 if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) {
Alex Kelly10c28d92012-09-26 21:52:08 -0400545 /* Setuid core dump mode */
546 flag = O_EXCL; /* Stop rewrite attacks */
547 cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */
548 need_nonrelative = true;
549 }
550
Denys Vlasenko5ab1c302012-10-04 17:15:29 -0700551 retval = coredump_wait(siginfo->si_signo, &core_state);
Alex Kelly10c28d92012-09-26 21:52:08 -0400552 if (retval < 0)
553 goto fail_creds;
554
555 old_cred = override_creds(cred);
556
Oleg Nesterov12a2b4b2012-10-04 17:15:25 -0700557 ispipe = format_corename(&cn, &cprm);
Alex Kelly10c28d92012-09-26 21:52:08 -0400558
Lucas De Marchifb96c472013-04-30 15:28:06 -0700559 if (ispipe) {
Alex Kelly10c28d92012-09-26 21:52:08 -0400560 int dump_count;
561 char **helper_argv;
Lucas De Marchi907ed132013-04-30 15:28:07 -0700562 struct subprocess_info *sub_info;
Alex Kelly10c28d92012-09-26 21:52:08 -0400563
564 if (ispipe < 0) {
565 printk(KERN_WARNING "format_corename failed\n");
566 printk(KERN_WARNING "Aborting core\n");
Oleg Nesterove7fd1542013-07-03 15:08:16 -0700567 goto fail_unlock;
Alex Kelly10c28d92012-09-26 21:52:08 -0400568 }
569
570 if (cprm.limit == 1) {
571 /* See umh_pipe_setup() which sets RLIMIT_CORE = 1.
572 *
573 * Normally core limits are irrelevant to pipes, since
574 * we're not writing to the file system, but we use
575 * cprm.limit of 1 here as a speacial value, this is a
576 * consistent way to catch recursive crashes.
577 * We can still crash if the core_pattern binary sets
578 * RLIM_CORE = !1, but it runs as root, and can do
579 * lots of stupid things.
580 *
581 * Note that we use task_tgid_vnr here to grab the pid
582 * of the process group leader. That way we get the
583 * right pid if a thread in a multi-threaded
584 * core_pattern process dies.
585 */
586 printk(KERN_WARNING
587 "Process %d(%s) has RLIMIT_CORE set to 1\n",
588 task_tgid_vnr(current), current->comm);
589 printk(KERN_WARNING "Aborting core\n");
590 goto fail_unlock;
591 }
592 cprm.limit = RLIM_INFINITY;
593
594 dump_count = atomic_inc_return(&core_dump_count);
595 if (core_pipe_limit && (core_pipe_limit < dump_count)) {
596 printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n",
597 task_tgid_vnr(current), current->comm);
598 printk(KERN_WARNING "Skipping core dump\n");
599 goto fail_dropcount;
600 }
601
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700602 helper_argv = argv_split(GFP_KERNEL, cn.corename, NULL);
Alex Kelly10c28d92012-09-26 21:52:08 -0400603 if (!helper_argv) {
604 printk(KERN_WARNING "%s failed to allocate memory\n",
605 __func__);
606 goto fail_dropcount;
607 }
608
Lucas De Marchi907ed132013-04-30 15:28:07 -0700609 retval = -ENOMEM;
610 sub_info = call_usermodehelper_setup(helper_argv[0],
611 helper_argv, NULL, GFP_KERNEL,
612 umh_pipe_setup, NULL, &cprm);
613 if (sub_info)
614 retval = call_usermodehelper_exec(sub_info,
615 UMH_WAIT_EXEC);
616
Alex Kelly10c28d92012-09-26 21:52:08 -0400617 argv_free(helper_argv);
618 if (retval) {
Oleg Nesterov888ffc52013-07-03 15:08:23 -0700619 printk(KERN_INFO "Core dump to |%s pipe failed\n",
Alex Kelly10c28d92012-09-26 21:52:08 -0400620 cn.corename);
621 goto close_fail;
Lucas De Marchifb96c472013-04-30 15:28:06 -0700622 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400623 } else {
624 struct inode *inode;
625
626 if (cprm.limit < binfmt->min_coredump)
627 goto fail_unlock;
628
629 if (need_nonrelative && cn.corename[0] != '/') {
630 printk(KERN_WARNING "Pid %d(%s) can only dump core "\
631 "to fully qualified path!\n",
632 task_tgid_vnr(current), current->comm);
633 printk(KERN_WARNING "Skipping core dump\n");
634 goto fail_unlock;
635 }
636
637 cprm.file = filp_open(cn.corename,
638 O_CREAT | 2 | O_NOFOLLOW | O_LARGEFILE | flag,
639 0600);
640 if (IS_ERR(cprm.file))
641 goto fail_unlock;
642
Al Viro496ad9a2013-01-23 17:07:38 -0500643 inode = file_inode(cprm.file);
Alex Kelly10c28d92012-09-26 21:52:08 -0400644 if (inode->i_nlink > 1)
645 goto close_fail;
646 if (d_unhashed(cprm.file->f_path.dentry))
647 goto close_fail;
648 /*
649 * AK: actually i see no reason to not allow this for named
650 * pipes etc, but keep the previous behaviour for now.
651 */
652 if (!S_ISREG(inode->i_mode))
653 goto close_fail;
654 /*
655 * Dont allow local users get cute and trick others to coredump
656 * into their pre-created files.
657 */
658 if (!uid_eq(inode->i_uid, current_fsuid()))
659 goto close_fail;
Al Viro72c2d532013-09-22 16:27:52 -0400660 if (!cprm.file->f_op->write)
Alex Kelly10c28d92012-09-26 21:52:08 -0400661 goto close_fail;
662 if (do_truncate(cprm.file->f_path.dentry, 0, 0, cprm.file))
663 goto close_fail;
664 }
665
666 /* get us an unshared descriptor table; almost always a no-op */
667 retval = unshare_files(&displaced);
668 if (retval)
669 goto close_fail;
670 if (displaced)
671 put_files_struct(displaced);
Al Viroe86d35c2013-05-04 14:45:54 -0400672 if (!dump_interrupted()) {
673 file_start_write(cprm.file);
674 core_dumped = binfmt->core_dump(&cprm);
675 file_end_write(cprm.file);
676 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400677 if (ispipe && core_pipe_limit)
678 wait_for_dump_helpers(cprm.file);
679close_fail:
680 if (cprm.file)
681 filp_close(cprm.file, NULL);
682fail_dropcount:
683 if (ispipe)
684 atomic_dec(&core_dump_count);
685fail_unlock:
686 kfree(cn.corename);
Oleg Nesterovacdedd92013-04-30 15:28:13 -0700687 coredump_finish(mm, core_dumped);
Alex Kelly10c28d92012-09-26 21:52:08 -0400688 revert_creds(old_cred);
689fail_creds:
690 put_cred(cred);
691fail:
692 return;
693}
694
695/*
696 * Core dumping helper functions. These are the only things you should
697 * do on a core-file: use only these functions to write out all the
698 * necessary info.
699 */
Al Viroecc8c772013-10-05 15:32:35 -0400700int dump_emit(struct coredump_params *cprm, const void *addr, int nr)
701{
702 struct file *file = cprm->file;
Al Viro2507a4f2013-10-08 09:11:48 -0400703 loff_t pos = file->f_pos;
704 ssize_t n;
Al Viroecc8c772013-10-05 15:32:35 -0400705 if (cprm->written + nr > cprm->limit)
706 return 0;
Al Viro2507a4f2013-10-08 09:11:48 -0400707 while (nr) {
708 if (dump_interrupted())
709 return 0;
Al Viro52da40a2013-11-15 21:58:33 -0500710 n = __kernel_write(file, addr, nr, &pos);
Al Viro2507a4f2013-10-08 09:11:48 -0400711 if (n <= 0)
712 return 0;
713 file->f_pos = pos;
714 cprm->written += n;
715 nr -= n;
716 }
Al Viroecc8c772013-10-05 15:32:35 -0400717 return 1;
718}
719EXPORT_SYMBOL(dump_emit);
720
Al Viro9b56d542013-10-08 09:26:08 -0400721int dump_skip(struct coredump_params *cprm, size_t nr)
Alex Kelly10c28d92012-09-26 21:52:08 -0400722{
Al Viro9b56d542013-10-08 09:26:08 -0400723 static char zeroes[PAGE_SIZE];
724 struct file *file = cprm->file;
Alex Kelly10c28d92012-09-26 21:52:08 -0400725 if (file->f_op->llseek && file->f_op->llseek != no_llseek) {
Al Viro9b56d542013-10-08 09:26:08 -0400726 if (cprm->written + nr > cprm->limit)
727 return 0;
Oleg Nesterov528f8272013-04-30 15:28:15 -0700728 if (dump_interrupted() ||
Al Viro9b56d542013-10-08 09:26:08 -0400729 file->f_op->llseek(file, nr, SEEK_CUR) < 0)
Alex Kelly10c28d92012-09-26 21:52:08 -0400730 return 0;
Al Viro9b56d542013-10-08 09:26:08 -0400731 cprm->written += nr;
732 return 1;
Alex Kelly10c28d92012-09-26 21:52:08 -0400733 } else {
Al Viro9b56d542013-10-08 09:26:08 -0400734 while (nr > PAGE_SIZE) {
735 if (!dump_emit(cprm, zeroes, PAGE_SIZE))
736 return 0;
737 nr -= PAGE_SIZE;
Alex Kelly10c28d92012-09-26 21:52:08 -0400738 }
Al Viro9b56d542013-10-08 09:26:08 -0400739 return dump_emit(cprm, zeroes, nr);
Alex Kelly10c28d92012-09-26 21:52:08 -0400740 }
Alex Kelly10c28d92012-09-26 21:52:08 -0400741}
Al Viro9b56d542013-10-08 09:26:08 -0400742EXPORT_SYMBOL(dump_skip);
Al Viro22a8cb82013-10-08 11:05:01 -0400743
744int dump_align(struct coredump_params *cprm, int align)
745{
746 unsigned mod = cprm->written & (align - 1);
747 if (align & (align - 1))
Al Virodb512422013-11-15 21:55:52 -0500748 return 0;
749 return mod ? dump_skip(cprm, align - mod) : 1;
Al Viro22a8cb82013-10-08 11:05:01 -0400750}
751EXPORT_SYMBOL(dump_align);