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b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
10c28d93 AK |
2 | #include <linux/slab.h> |
3 | #include <linux/file.h> | |
4 | #include <linux/fdtable.h> | |
70d78fe7 | 5 | #include <linux/freezer.h> |
10c28d93 AK |
6 | #include <linux/mm.h> |
7 | #include <linux/stat.h> | |
8 | #include <linux/fcntl.h> | |
9 | #include <linux/swap.h> | |
315c6926 | 10 | #include <linux/ctype.h> |
10c28d93 AK |
11 | #include <linux/string.h> |
12 | #include <linux/init.h> | |
13 | #include <linux/pagemap.h> | |
14 | #include <linux/perf_event.h> | |
15 | #include <linux/highmem.h> | |
16 | #include <linux/spinlock.h> | |
17 | #include <linux/key.h> | |
18 | #include <linux/personality.h> | |
19 | #include <linux/binfmts.h> | |
179899fd | 20 | #include <linux/coredump.h> |
f7ccbae4 | 21 | #include <linux/sched/coredump.h> |
3f07c014 | 22 | #include <linux/sched/signal.h> |
68db0cf1 | 23 | #include <linux/sched/task_stack.h> |
10c28d93 AK |
24 | #include <linux/utsname.h> |
25 | #include <linux/pid_namespace.h> | |
26 | #include <linux/module.h> | |
27 | #include <linux/namei.h> | |
28 | #include <linux/mount.h> | |
29 | #include <linux/security.h> | |
30 | #include <linux/syscalls.h> | |
31 | #include <linux/tsacct_kern.h> | |
32 | #include <linux/cn_proc.h> | |
33 | #include <linux/audit.h> | |
34 | #include <linux/tracehook.h> | |
35 | #include <linux/kmod.h> | |
36 | #include <linux/fsnotify.h> | |
37 | #include <linux/fs_struct.h> | |
38 | #include <linux/pipe_fs_i.h> | |
39 | #include <linux/oom.h> | |
40 | #include <linux/compat.h> | |
378c6520 JH |
41 | #include <linux/fs.h> |
42 | #include <linux/path.h> | |
03927c8a | 43 | #include <linux/timekeeping.h> |
28f2c9f0 | 44 | #include <linux/elf.h> |
10c28d93 | 45 | |
7c0f6ba6 | 46 | #include <linux/uaccess.h> |
10c28d93 AK |
47 | #include <asm/mmu_context.h> |
48 | #include <asm/tlb.h> | |
49 | #include <asm/exec.h> | |
50 | ||
51 | #include <trace/events/task.h> | |
52 | #include "internal.h" | |
53 | ||
54 | #include <trace/events/sched.h> | |
55 | ||
b2708174 | 56 | static bool dump_vma_snapshot(struct coredump_params *cprm); |
8032409c | 57 | static void free_vma_snapshot(struct coredump_params *cprm); |
b2708174 | 58 | |
10c28d93 | 59 | int core_uses_pid; |
10c28d93 | 60 | unsigned int core_pipe_limit; |
3ceadcf6 ON |
61 | char core_pattern[CORENAME_MAX_SIZE] = "core"; |
62 | static int core_name_size = CORENAME_MAX_SIZE; | |
10c28d93 AK |
63 | |
64 | struct core_name { | |
65 | char *corename; | |
66 | int used, size; | |
67 | }; | |
10c28d93 AK |
68 | |
69 | /* The maximal length of core_pattern is also specified in sysctl.c */ | |
70 | ||
3ceadcf6 | 71 | static int expand_corename(struct core_name *cn, int size) |
10c28d93 | 72 | { |
e7fd1549 | 73 | char *corename = krealloc(cn->corename, size, GFP_KERNEL); |
10c28d93 | 74 | |
e7fd1549 | 75 | if (!corename) |
10c28d93 | 76 | return -ENOMEM; |
10c28d93 | 77 | |
3ceadcf6 ON |
78 | if (size > core_name_size) /* racy but harmless */ |
79 | core_name_size = size; | |
80 | ||
81 | cn->size = ksize(corename); | |
e7fd1549 | 82 | cn->corename = corename; |
10c28d93 AK |
83 | return 0; |
84 | } | |
85 | ||
b4176b7c NI |
86 | static __printf(2, 0) int cn_vprintf(struct core_name *cn, const char *fmt, |
87 | va_list arg) | |
10c28d93 | 88 | { |
5fe9d8ca | 89 | int free, need; |
404ca80e | 90 | va_list arg_copy; |
10c28d93 | 91 | |
5fe9d8ca ON |
92 | again: |
93 | free = cn->size - cn->used; | |
404ca80e ED |
94 | |
95 | va_copy(arg_copy, arg); | |
96 | need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy); | |
97 | va_end(arg_copy); | |
98 | ||
5fe9d8ca ON |
99 | if (need < free) { |
100 | cn->used += need; | |
101 | return 0; | |
102 | } | |
10c28d93 | 103 | |
3ceadcf6 | 104 | if (!expand_corename(cn, cn->size + need - free + 1)) |
5fe9d8ca | 105 | goto again; |
10c28d93 | 106 | |
5fe9d8ca | 107 | return -ENOMEM; |
10c28d93 AK |
108 | } |
109 | ||
b4176b7c | 110 | static __printf(2, 3) int cn_printf(struct core_name *cn, const char *fmt, ...) |
bc03c691 ON |
111 | { |
112 | va_list arg; | |
113 | int ret; | |
114 | ||
115 | va_start(arg, fmt); | |
116 | ret = cn_vprintf(cn, fmt, arg); | |
117 | va_end(arg); | |
118 | ||
119 | return ret; | |
120 | } | |
121 | ||
b4176b7c NI |
122 | static __printf(2, 3) |
123 | int cn_esc_printf(struct core_name *cn, const char *fmt, ...) | |
10c28d93 | 124 | { |
923bed03 ON |
125 | int cur = cn->used; |
126 | va_list arg; | |
127 | int ret; | |
128 | ||
129 | va_start(arg, fmt); | |
130 | ret = cn_vprintf(cn, fmt, arg); | |
131 | va_end(arg); | |
132 | ||
ac94b6e3 JH |
133 | if (ret == 0) { |
134 | /* | |
135 | * Ensure that this coredump name component can't cause the | |
136 | * resulting corefile path to consist of a ".." or ".". | |
137 | */ | |
138 | if ((cn->used - cur == 1 && cn->corename[cur] == '.') || | |
139 | (cn->used - cur == 2 && cn->corename[cur] == '.' | |
140 | && cn->corename[cur+1] == '.')) | |
141 | cn->corename[cur] = '!'; | |
142 | ||
143 | /* | |
144 | * Empty names are fishy and could be used to create a "//" in a | |
145 | * corefile name, causing the coredump to happen one directory | |
146 | * level too high. Enforce that all components of the core | |
147 | * pattern are at least one character long. | |
148 | */ | |
149 | if (cn->used == cur) | |
150 | ret = cn_printf(cn, "!"); | |
151 | } | |
152 | ||
923bed03 ON |
153 | for (; cur < cn->used; ++cur) { |
154 | if (cn->corename[cur] == '/') | |
155 | cn->corename[cur] = '!'; | |
156 | } | |
157 | return ret; | |
10c28d93 AK |
158 | } |
159 | ||
f38c85f1 | 160 | static int cn_print_exe_file(struct core_name *cn, bool name_only) |
10c28d93 AK |
161 | { |
162 | struct file *exe_file; | |
f38c85f1 | 163 | char *pathbuf, *path, *ptr; |
10c28d93 AK |
164 | int ret; |
165 | ||
166 | exe_file = get_mm_exe_file(current->mm); | |
923bed03 ON |
167 | if (!exe_file) |
168 | return cn_esc_printf(cn, "%s (path unknown)", current->comm); | |
10c28d93 | 169 | |
0ee931c4 | 170 | pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); |
10c28d93 AK |
171 | if (!pathbuf) { |
172 | ret = -ENOMEM; | |
173 | goto put_exe_file; | |
174 | } | |
175 | ||
9bf39ab2 | 176 | path = file_path(exe_file, pathbuf, PATH_MAX); |
10c28d93 AK |
177 | if (IS_ERR(path)) { |
178 | ret = PTR_ERR(path); | |
179 | goto free_buf; | |
180 | } | |
181 | ||
f38c85f1 LW |
182 | if (name_only) { |
183 | ptr = strrchr(path, '/'); | |
184 | if (ptr) | |
185 | path = ptr + 1; | |
186 | } | |
923bed03 | 187 | ret = cn_esc_printf(cn, "%s", path); |
10c28d93 AK |
188 | |
189 | free_buf: | |
190 | kfree(pathbuf); | |
191 | put_exe_file: | |
192 | fput(exe_file); | |
193 | return ret; | |
194 | } | |
195 | ||
196 | /* format_corename will inspect the pattern parameter, and output a | |
197 | * name into corename, which must have space for at least | |
198 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
199 | */ | |
315c6926 PW |
200 | static int format_corename(struct core_name *cn, struct coredump_params *cprm, |
201 | size_t **argv, int *argc) | |
10c28d93 AK |
202 | { |
203 | const struct cred *cred = current_cred(); | |
204 | const char *pat_ptr = core_pattern; | |
205 | int ispipe = (*pat_ptr == '|'); | |
315c6926 | 206 | bool was_space = false; |
10c28d93 AK |
207 | int pid_in_pattern = 0; |
208 | int err = 0; | |
209 | ||
e7fd1549 | 210 | cn->used = 0; |
3ceadcf6 ON |
211 | cn->corename = NULL; |
212 | if (expand_corename(cn, core_name_size)) | |
10c28d93 | 213 | return -ENOMEM; |
888ffc59 ON |
214 | cn->corename[0] = '\0'; |
215 | ||
315c6926 PW |
216 | if (ispipe) { |
217 | int argvs = sizeof(core_pattern) / 2; | |
218 | (*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL); | |
219 | if (!(*argv)) | |
220 | return -ENOMEM; | |
221 | (*argv)[(*argc)++] = 0; | |
888ffc59 | 222 | ++pat_ptr; |
db973a72 SM |
223 | if (!(*pat_ptr)) |
224 | return -ENOMEM; | |
315c6926 | 225 | } |
10c28d93 AK |
226 | |
227 | /* Repeat as long as we have more pattern to process and more output | |
228 | space */ | |
229 | while (*pat_ptr) { | |
315c6926 PW |
230 | /* |
231 | * Split on spaces before doing template expansion so that | |
232 | * %e and %E don't get split if they have spaces in them | |
233 | */ | |
234 | if (ispipe) { | |
235 | if (isspace(*pat_ptr)) { | |
2bf509d9 MD |
236 | if (cn->used != 0) |
237 | was_space = true; | |
315c6926 PW |
238 | pat_ptr++; |
239 | continue; | |
240 | } else if (was_space) { | |
241 | was_space = false; | |
242 | err = cn_printf(cn, "%c", '\0'); | |
243 | if (err) | |
244 | return err; | |
245 | (*argv)[(*argc)++] = cn->used; | |
246 | } | |
247 | } | |
10c28d93 | 248 | if (*pat_ptr != '%') { |
10c28d93 AK |
249 | err = cn_printf(cn, "%c", *pat_ptr++); |
250 | } else { | |
251 | switch (*++pat_ptr) { | |
252 | /* single % at the end, drop that */ | |
253 | case 0: | |
254 | goto out; | |
255 | /* Double percent, output one percent */ | |
256 | case '%': | |
257 | err = cn_printf(cn, "%c", '%'); | |
258 | break; | |
259 | /* pid */ | |
260 | case 'p': | |
261 | pid_in_pattern = 1; | |
262 | err = cn_printf(cn, "%d", | |
263 | task_tgid_vnr(current)); | |
264 | break; | |
65aafb1e SG |
265 | /* global pid */ |
266 | case 'P': | |
267 | err = cn_printf(cn, "%d", | |
268 | task_tgid_nr(current)); | |
269 | break; | |
b03023ec ON |
270 | case 'i': |
271 | err = cn_printf(cn, "%d", | |
272 | task_pid_vnr(current)); | |
273 | break; | |
274 | case 'I': | |
275 | err = cn_printf(cn, "%d", | |
276 | task_pid_nr(current)); | |
277 | break; | |
10c28d93 AK |
278 | /* uid */ |
279 | case 'u': | |
5202efe5 NI |
280 | err = cn_printf(cn, "%u", |
281 | from_kuid(&init_user_ns, | |
282 | cred->uid)); | |
10c28d93 AK |
283 | break; |
284 | /* gid */ | |
285 | case 'g': | |
5202efe5 NI |
286 | err = cn_printf(cn, "%u", |
287 | from_kgid(&init_user_ns, | |
288 | cred->gid)); | |
10c28d93 | 289 | break; |
12a2b4b2 ON |
290 | case 'd': |
291 | err = cn_printf(cn, "%d", | |
292 | __get_dumpable(cprm->mm_flags)); | |
293 | break; | |
10c28d93 AK |
294 | /* signal that caused the coredump */ |
295 | case 's': | |
b4176b7c NI |
296 | err = cn_printf(cn, "%d", |
297 | cprm->siginfo->si_signo); | |
10c28d93 AK |
298 | break; |
299 | /* UNIX time of coredump */ | |
300 | case 't': { | |
03927c8a AB |
301 | time64_t time; |
302 | ||
303 | time = ktime_get_real_seconds(); | |
304 | err = cn_printf(cn, "%lld", time); | |
10c28d93 AK |
305 | break; |
306 | } | |
307 | /* hostname */ | |
923bed03 | 308 | case 'h': |
10c28d93 | 309 | down_read(&uts_sem); |
923bed03 | 310 | err = cn_esc_printf(cn, "%s", |
10c28d93 AK |
311 | utsname()->nodename); |
312 | up_read(&uts_sem); | |
10c28d93 | 313 | break; |
f38c85f1 | 314 | /* executable, could be changed by prctl PR_SET_NAME etc */ |
923bed03 ON |
315 | case 'e': |
316 | err = cn_esc_printf(cn, "%s", current->comm); | |
10c28d93 | 317 | break; |
f38c85f1 LW |
318 | /* file name of executable */ |
319 | case 'f': | |
320 | err = cn_print_exe_file(cn, true); | |
321 | break; | |
10c28d93 | 322 | case 'E': |
f38c85f1 | 323 | err = cn_print_exe_file(cn, false); |
10c28d93 AK |
324 | break; |
325 | /* core limit size */ | |
326 | case 'c': | |
327 | err = cn_printf(cn, "%lu", | |
328 | rlimit(RLIMIT_CORE)); | |
329 | break; | |
330 | default: | |
331 | break; | |
332 | } | |
333 | ++pat_ptr; | |
334 | } | |
335 | ||
336 | if (err) | |
337 | return err; | |
338 | } | |
339 | ||
888ffc59 | 340 | out: |
10c28d93 AK |
341 | /* Backward compatibility with core_uses_pid: |
342 | * | |
343 | * If core_pattern does not include a %p (as is the default) | |
344 | * and core_uses_pid is set, then .%pid will be appended to | |
345 | * the filename. Do not do this for piped commands. */ | |
346 | if (!ispipe && !pid_in_pattern && core_uses_pid) { | |
347 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); | |
348 | if (err) | |
349 | return err; | |
350 | } | |
10c28d93 AK |
351 | return ispipe; |
352 | } | |
353 | ||
5fa534c9 | 354 | static int zap_process(struct task_struct *start, int exit_code, int flags) |
10c28d93 AK |
355 | { |
356 | struct task_struct *t; | |
357 | int nr = 0; | |
358 | ||
5fa534c9 ON |
359 | /* ignore all signals except SIGKILL, see prepare_signal() */ |
360 | start->signal->flags = SIGNAL_GROUP_COREDUMP | flags; | |
10c28d93 AK |
361 | start->signal->group_exit_code = exit_code; |
362 | start->signal->group_stop_count = 0; | |
363 | ||
d61ba589 | 364 | for_each_thread(start, t) { |
10c28d93 AK |
365 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
366 | if (t != current && t->mm) { | |
367 | sigaddset(&t->pending.signal, SIGKILL); | |
368 | signal_wake_up(t, 1); | |
369 | nr++; | |
370 | } | |
d61ba589 | 371 | } |
10c28d93 AK |
372 | |
373 | return nr; | |
374 | } | |
375 | ||
403bad72 ON |
376 | static int zap_threads(struct task_struct *tsk, struct mm_struct *mm, |
377 | struct core_state *core_state, int exit_code) | |
10c28d93 AK |
378 | { |
379 | struct task_struct *g, *p; | |
380 | unsigned long flags; | |
381 | int nr = -EAGAIN; | |
382 | ||
383 | spin_lock_irq(&tsk->sighand->siglock); | |
384 | if (!signal_group_exit(tsk->signal)) { | |
385 | mm->core_state = core_state; | |
6cd8f0ac | 386 | tsk->signal->group_exit_task = tsk; |
5fa534c9 | 387 | nr = zap_process(tsk, exit_code, 0); |
403bad72 | 388 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING); |
10c28d93 AK |
389 | } |
390 | spin_unlock_irq(&tsk->sighand->siglock); | |
391 | if (unlikely(nr < 0)) | |
392 | return nr; | |
393 | ||
aed8adb7 | 394 | tsk->flags |= PF_DUMPCORE; |
10c28d93 AK |
395 | if (atomic_read(&mm->mm_users) == nr + 1) |
396 | goto done; | |
397 | /* | |
398 | * We should find and kill all tasks which use this mm, and we should | |
399 | * count them correctly into ->nr_threads. We don't take tasklist | |
400 | * lock, but this is safe wrt: | |
401 | * | |
402 | * fork: | |
403 | * None of sub-threads can fork after zap_process(leader). All | |
404 | * processes which were created before this point should be | |
405 | * visible to zap_threads() because copy_process() adds the new | |
406 | * process to the tail of init_task.tasks list, and lock/unlock | |
407 | * of ->siglock provides a memory barrier. | |
408 | * | |
409 | * do_exit: | |
c1e8d7c6 | 410 | * The caller holds mm->mmap_lock. This means that the task which |
10c28d93 AK |
411 | * uses this mm can't pass exit_mm(), so it can't exit or clear |
412 | * its ->mm. | |
413 | * | |
414 | * de_thread: | |
415 | * It does list_replace_rcu(&leader->tasks, ¤t->tasks), | |
416 | * we must see either old or new leader, this does not matter. | |
417 | * However, it can change p->sighand, so lock_task_sighand(p) | |
c1e8d7c6 | 418 | * must be used. Since p->mm != NULL and we hold ->mmap_lock |
10c28d93 AK |
419 | * it can't fail. |
420 | * | |
421 | * Note also that "g" can be the old leader with ->mm == NULL | |
422 | * and already unhashed and thus removed from ->thread_group. | |
423 | * This is OK, __unhash_process()->list_del_rcu() does not | |
424 | * clear the ->next pointer, we will find the new leader via | |
425 | * next_thread(). | |
426 | */ | |
427 | rcu_read_lock(); | |
428 | for_each_process(g) { | |
429 | if (g == tsk->group_leader) | |
430 | continue; | |
431 | if (g->flags & PF_KTHREAD) | |
432 | continue; | |
d61ba589 ON |
433 | |
434 | for_each_thread(g, p) { | |
435 | if (unlikely(!p->mm)) | |
436 | continue; | |
437 | if (unlikely(p->mm == mm)) { | |
438 | lock_task_sighand(p, &flags); | |
439 | nr += zap_process(p, exit_code, | |
440 | SIGNAL_GROUP_EXIT); | |
441 | unlock_task_sighand(p, &flags); | |
10c28d93 | 442 | } |
d61ba589 ON |
443 | break; |
444 | } | |
10c28d93 AK |
445 | } |
446 | rcu_read_unlock(); | |
447 | done: | |
448 | atomic_set(&core_state->nr_threads, nr); | |
449 | return nr; | |
450 | } | |
451 | ||
452 | static int coredump_wait(int exit_code, struct core_state *core_state) | |
453 | { | |
454 | struct task_struct *tsk = current; | |
455 | struct mm_struct *mm = tsk->mm; | |
456 | int core_waiters = -EBUSY; | |
457 | ||
458 | init_completion(&core_state->startup); | |
459 | core_state->dumper.task = tsk; | |
460 | core_state->dumper.next = NULL; | |
461 | ||
d8ed45c5 | 462 | if (mmap_write_lock_killable(mm)) |
4136c26b MH |
463 | return -EINTR; |
464 | ||
10c28d93 AK |
465 | if (!mm->core_state) |
466 | core_waiters = zap_threads(tsk, mm, core_state, exit_code); | |
d8ed45c5 | 467 | mmap_write_unlock(mm); |
10c28d93 AK |
468 | |
469 | if (core_waiters > 0) { | |
470 | struct core_thread *ptr; | |
471 | ||
70d78fe7 | 472 | freezer_do_not_count(); |
10c28d93 | 473 | wait_for_completion(&core_state->startup); |
70d78fe7 | 474 | freezer_count(); |
10c28d93 AK |
475 | /* |
476 | * Wait for all the threads to become inactive, so that | |
477 | * all the thread context (extended register state, like | |
478 | * fpu etc) gets copied to the memory. | |
479 | */ | |
480 | ptr = core_state->dumper.next; | |
481 | while (ptr != NULL) { | |
482 | wait_task_inactive(ptr->task, 0); | |
483 | ptr = ptr->next; | |
484 | } | |
485 | } | |
486 | ||
487 | return core_waiters; | |
488 | } | |
489 | ||
acdedd99 | 490 | static void coredump_finish(struct mm_struct *mm, bool core_dumped) |
10c28d93 AK |
491 | { |
492 | struct core_thread *curr, *next; | |
493 | struct task_struct *task; | |
494 | ||
6cd8f0ac | 495 | spin_lock_irq(¤t->sighand->siglock); |
acdedd99 ON |
496 | if (core_dumped && !__fatal_signal_pending(current)) |
497 | current->signal->group_exit_code |= 0x80; | |
6cd8f0ac ON |
498 | current->signal->group_exit_task = NULL; |
499 | current->signal->flags = SIGNAL_GROUP_EXIT; | |
500 | spin_unlock_irq(¤t->sighand->siglock); | |
501 | ||
10c28d93 AK |
502 | next = mm->core_state->dumper.next; |
503 | while ((curr = next) != NULL) { | |
504 | next = curr->next; | |
505 | task = curr->task; | |
506 | /* | |
507 | * see exit_mm(), curr->task must not see | |
508 | * ->task == NULL before we read ->next. | |
509 | */ | |
510 | smp_mb(); | |
511 | curr->task = NULL; | |
512 | wake_up_process(task); | |
513 | } | |
514 | ||
515 | mm->core_state = NULL; | |
516 | } | |
517 | ||
528f827e ON |
518 | static bool dump_interrupted(void) |
519 | { | |
520 | /* | |
521 | * SIGKILL or freezing() interrupt the coredumping. Perhaps we | |
522 | * can do try_to_freeze() and check __fatal_signal_pending(), | |
523 | * but then we need to teach dump_write() to restart and clear | |
524 | * TIF_SIGPENDING. | |
525 | */ | |
06af8679 | 526 | return fatal_signal_pending(current) || freezing(current); |
528f827e ON |
527 | } |
528 | ||
10c28d93 AK |
529 | static void wait_for_dump_helpers(struct file *file) |
530 | { | |
de32ec4c | 531 | struct pipe_inode_info *pipe = file->private_data; |
10c28d93 AK |
532 | |
533 | pipe_lock(pipe); | |
534 | pipe->readers++; | |
535 | pipe->writers--; | |
0ddad21d | 536 | wake_up_interruptible_sync(&pipe->rd_wait); |
dc7ee2aa ON |
537 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
538 | pipe_unlock(pipe); | |
10c28d93 | 539 | |
dc7ee2aa ON |
540 | /* |
541 | * We actually want wait_event_freezable() but then we need | |
542 | * to clear TIF_SIGPENDING and improve dump_interrupted(). | |
543 | */ | |
0ddad21d | 544 | wait_event_interruptible(pipe->rd_wait, pipe->readers == 1); |
10c28d93 | 545 | |
dc7ee2aa | 546 | pipe_lock(pipe); |
10c28d93 AK |
547 | pipe->readers--; |
548 | pipe->writers++; | |
549 | pipe_unlock(pipe); | |
10c28d93 AK |
550 | } |
551 | ||
552 | /* | |
553 | * umh_pipe_setup | |
554 | * helper function to customize the process used | |
555 | * to collect the core in userspace. Specifically | |
556 | * it sets up a pipe and installs it as fd 0 (stdin) | |
557 | * for the process. Returns 0 on success, or | |
558 | * PTR_ERR on failure. | |
559 | * Note that it also sets the core limit to 1. This | |
560 | * is a special value that we use to trap recursive | |
561 | * core dumps | |
562 | */ | |
563 | static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) | |
564 | { | |
565 | struct file *files[2]; | |
566 | struct coredump_params *cp = (struct coredump_params *)info->data; | |
567 | int err = create_pipe_files(files, 0); | |
568 | if (err) | |
569 | return err; | |
570 | ||
571 | cp->file = files[1]; | |
572 | ||
45525b26 AV |
573 | err = replace_fd(0, files[0], 0); |
574 | fput(files[0]); | |
10c28d93 AK |
575 | /* and disallow core files too */ |
576 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; | |
577 | ||
45525b26 | 578 | return err; |
10c28d93 AK |
579 | } |
580 | ||
ae7795bc | 581 | void do_coredump(const kernel_siginfo_t *siginfo) |
10c28d93 AK |
582 | { |
583 | struct core_state core_state; | |
584 | struct core_name cn; | |
585 | struct mm_struct *mm = current->mm; | |
586 | struct linux_binfmt * binfmt; | |
587 | const struct cred *old_cred; | |
588 | struct cred *cred; | |
589 | int retval = 0; | |
10c28d93 | 590 | int ispipe; |
315c6926 PW |
591 | size_t *argv = NULL; |
592 | int argc = 0; | |
fbb18169 JH |
593 | /* require nonrelative corefile path and be extra careful */ |
594 | bool need_suid_safe = false; | |
acdedd99 | 595 | bool core_dumped = false; |
10c28d93 AK |
596 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
597 | struct coredump_params cprm = { | |
5ab1c309 | 598 | .siginfo = siginfo, |
541880d9 | 599 | .regs = signal_pt_regs(), |
10c28d93 AK |
600 | .limit = rlimit(RLIMIT_CORE), |
601 | /* | |
602 | * We must use the same mm->flags while dumping core to avoid | |
603 | * inconsistency of bit flags, since this flag is not protected | |
604 | * by any locks. | |
605 | */ | |
606 | .mm_flags = mm->flags, | |
b2708174 | 607 | .vma_meta = NULL, |
10c28d93 AK |
608 | }; |
609 | ||
5ab1c309 | 610 | audit_core_dumps(siginfo->si_signo); |
10c28d93 AK |
611 | |
612 | binfmt = mm->binfmt; | |
613 | if (!binfmt || !binfmt->core_dump) | |
614 | goto fail; | |
615 | if (!__get_dumpable(cprm.mm_flags)) | |
616 | goto fail; | |
617 | ||
618 | cred = prepare_creds(); | |
619 | if (!cred) | |
620 | goto fail; | |
621 | /* | |
622 | * We cannot trust fsuid as being the "true" uid of the process | |
623 | * nor do we know its entire history. We only know it was tainted | |
624 | * so we dump it as root in mode 2, and only into a controlled | |
625 | * environment (pipe handler or fully qualified path). | |
626 | */ | |
e579d2c2 | 627 | if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) { |
10c28d93 | 628 | /* Setuid core dump mode */ |
10c28d93 | 629 | cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ |
fbb18169 | 630 | need_suid_safe = true; |
10c28d93 AK |
631 | } |
632 | ||
5ab1c309 | 633 | retval = coredump_wait(siginfo->si_signo, &core_state); |
10c28d93 AK |
634 | if (retval < 0) |
635 | goto fail_creds; | |
636 | ||
637 | old_cred = override_creds(cred); | |
638 | ||
315c6926 | 639 | ispipe = format_corename(&cn, &cprm, &argv, &argc); |
10c28d93 | 640 | |
fb96c475 | 641 | if (ispipe) { |
315c6926 | 642 | int argi; |
10c28d93 AK |
643 | int dump_count; |
644 | char **helper_argv; | |
907ed132 | 645 | struct subprocess_info *sub_info; |
10c28d93 AK |
646 | |
647 | if (ispipe < 0) { | |
648 | printk(KERN_WARNING "format_corename failed\n"); | |
649 | printk(KERN_WARNING "Aborting core\n"); | |
e7fd1549 | 650 | goto fail_unlock; |
10c28d93 AK |
651 | } |
652 | ||
653 | if (cprm.limit == 1) { | |
654 | /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. | |
655 | * | |
656 | * Normally core limits are irrelevant to pipes, since | |
657 | * we're not writing to the file system, but we use | |
fcbc32bc | 658 | * cprm.limit of 1 here as a special value, this is a |
10c28d93 AK |
659 | * consistent way to catch recursive crashes. |
660 | * We can still crash if the core_pattern binary sets | |
661 | * RLIM_CORE = !1, but it runs as root, and can do | |
662 | * lots of stupid things. | |
663 | * | |
664 | * Note that we use task_tgid_vnr here to grab the pid | |
665 | * of the process group leader. That way we get the | |
666 | * right pid if a thread in a multi-threaded | |
667 | * core_pattern process dies. | |
668 | */ | |
669 | printk(KERN_WARNING | |
670 | "Process %d(%s) has RLIMIT_CORE set to 1\n", | |
671 | task_tgid_vnr(current), current->comm); | |
672 | printk(KERN_WARNING "Aborting core\n"); | |
673 | goto fail_unlock; | |
674 | } | |
675 | cprm.limit = RLIM_INFINITY; | |
676 | ||
677 | dump_count = atomic_inc_return(&core_dump_count); | |
678 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { | |
679 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", | |
680 | task_tgid_vnr(current), current->comm); | |
681 | printk(KERN_WARNING "Skipping core dump\n"); | |
682 | goto fail_dropcount; | |
683 | } | |
684 | ||
315c6926 PW |
685 | helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), |
686 | GFP_KERNEL); | |
10c28d93 AK |
687 | if (!helper_argv) { |
688 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
689 | __func__); | |
690 | goto fail_dropcount; | |
691 | } | |
315c6926 PW |
692 | for (argi = 0; argi < argc; argi++) |
693 | helper_argv[argi] = cn.corename + argv[argi]; | |
694 | helper_argv[argi] = NULL; | |
10c28d93 | 695 | |
907ed132 LDM |
696 | retval = -ENOMEM; |
697 | sub_info = call_usermodehelper_setup(helper_argv[0], | |
698 | helper_argv, NULL, GFP_KERNEL, | |
699 | umh_pipe_setup, NULL, &cprm); | |
700 | if (sub_info) | |
701 | retval = call_usermodehelper_exec(sub_info, | |
702 | UMH_WAIT_EXEC); | |
703 | ||
315c6926 | 704 | kfree(helper_argv); |
10c28d93 | 705 | if (retval) { |
888ffc59 | 706 | printk(KERN_INFO "Core dump to |%s pipe failed\n", |
10c28d93 AK |
707 | cn.corename); |
708 | goto close_fail; | |
fb96c475 | 709 | } |
10c28d93 | 710 | } else { |
643fe55a | 711 | struct user_namespace *mnt_userns; |
10c28d93 | 712 | struct inode *inode; |
378c6520 JH |
713 | int open_flags = O_CREAT | O_RDWR | O_NOFOLLOW | |
714 | O_LARGEFILE | O_EXCL; | |
10c28d93 AK |
715 | |
716 | if (cprm.limit < binfmt->min_coredump) | |
717 | goto fail_unlock; | |
718 | ||
fbb18169 | 719 | if (need_suid_safe && cn.corename[0] != '/') { |
10c28d93 AK |
720 | printk(KERN_WARNING "Pid %d(%s) can only dump core "\ |
721 | "to fully qualified path!\n", | |
722 | task_tgid_vnr(current), current->comm); | |
723 | printk(KERN_WARNING "Skipping core dump\n"); | |
724 | goto fail_unlock; | |
725 | } | |
726 | ||
fbb18169 JH |
727 | /* |
728 | * Unlink the file if it exists unless this is a SUID | |
729 | * binary - in that case, we're running around with root | |
730 | * privs and don't want to unlink another user's coredump. | |
731 | */ | |
732 | if (!need_suid_safe) { | |
fbb18169 JH |
733 | /* |
734 | * If it doesn't exist, that's fine. If there's some | |
735 | * other problem, we'll catch it at the filp_open(). | |
736 | */ | |
96271654 | 737 | do_unlinkat(AT_FDCWD, getname_kernel(cn.corename)); |
fbb18169 JH |
738 | } |
739 | ||
740 | /* | |
741 | * There is a race between unlinking and creating the | |
742 | * file, but if that causes an EEXIST here, that's | |
743 | * fine - another process raced with us while creating | |
744 | * the corefile, and the other process won. To userspace, | |
745 | * what matters is that at least one of the two processes | |
746 | * writes its coredump successfully, not which one. | |
747 | */ | |
378c6520 JH |
748 | if (need_suid_safe) { |
749 | /* | |
750 | * Using user namespaces, normal user tasks can change | |
751 | * their current->fs->root to point to arbitrary | |
752 | * directories. Since the intention of the "only dump | |
753 | * with a fully qualified path" rule is to control where | |
754 | * coredumps may be placed using root privileges, | |
755 | * current->fs->root must not be used. Instead, use the | |
756 | * root directory of init_task. | |
757 | */ | |
758 | struct path root; | |
759 | ||
760 | task_lock(&init_task); | |
761 | get_fs_root(init_task.fs, &root); | |
762 | task_unlock(&init_task); | |
ffb37ca3 AV |
763 | cprm.file = file_open_root(&root, cn.corename, |
764 | open_flags, 0600); | |
378c6520 JH |
765 | path_put(&root); |
766 | } else { | |
767 | cprm.file = filp_open(cn.corename, open_flags, 0600); | |
768 | } | |
10c28d93 AK |
769 | if (IS_ERR(cprm.file)) |
770 | goto fail_unlock; | |
771 | ||
496ad9aa | 772 | inode = file_inode(cprm.file); |
10c28d93 AK |
773 | if (inode->i_nlink > 1) |
774 | goto close_fail; | |
775 | if (d_unhashed(cprm.file->f_path.dentry)) | |
776 | goto close_fail; | |
777 | /* | |
778 | * AK: actually i see no reason to not allow this for named | |
779 | * pipes etc, but keep the previous behaviour for now. | |
780 | */ | |
781 | if (!S_ISREG(inode->i_mode)) | |
782 | goto close_fail; | |
783 | /* | |
40f705a7 JH |
784 | * Don't dump core if the filesystem changed owner or mode |
785 | * of the file during file creation. This is an issue when | |
786 | * a process dumps core while its cwd is e.g. on a vfat | |
787 | * filesystem. | |
10c28d93 | 788 | */ |
643fe55a | 789 | mnt_userns = file_mnt_user_ns(cprm.file); |
dbd9d6f8 DO |
790 | if (!uid_eq(i_uid_into_mnt(mnt_userns, inode), |
791 | current_fsuid())) { | |
792 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n", | |
793 | cn.corename); | |
10c28d93 | 794 | goto close_fail; |
dbd9d6f8 DO |
795 | } |
796 | if ((inode->i_mode & 0677) != 0600) { | |
797 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file permissions\n", | |
798 | cn.corename); | |
40f705a7 | 799 | goto close_fail; |
dbd9d6f8 | 800 | } |
86cc0584 | 801 | if (!(cprm.file->f_mode & FMODE_CAN_WRITE)) |
10c28d93 | 802 | goto close_fail; |
643fe55a CB |
803 | if (do_truncate(mnt_userns, cprm.file->f_path.dentry, |
804 | 0, 0, cprm.file)) | |
10c28d93 AK |
805 | goto close_fail; |
806 | } | |
807 | ||
808 | /* get us an unshared descriptor table; almost always a no-op */ | |
c39ab6de | 809 | /* The cell spufs coredump code reads the file descriptor tables */ |
1f702603 | 810 | retval = unshare_files(); |
10c28d93 AK |
811 | if (retval) |
812 | goto close_fail; | |
e86d35c3 | 813 | if (!dump_interrupted()) { |
3740d93e LC |
814 | /* |
815 | * umh disabled with CONFIG_STATIC_USERMODEHELPER_PATH="" would | |
816 | * have this set to NULL. | |
817 | */ | |
818 | if (!cprm.file) { | |
819 | pr_info("Core dump to |%s disabled\n", cn.corename); | |
820 | goto close_fail; | |
821 | } | |
b2708174 EB |
822 | if (!dump_vma_snapshot(&cprm)) |
823 | goto close_fail; | |
824 | ||
e86d35c3 AV |
825 | file_start_write(cprm.file); |
826 | core_dumped = binfmt->core_dump(&cprm); | |
d0f1088b AV |
827 | /* |
828 | * Ensures that file size is big enough to contain the current | |
829 | * file postion. This prevents gdb from complaining about | |
830 | * a truncated file if the last "write" to the file was | |
831 | * dump_skip. | |
832 | */ | |
833 | if (cprm.to_skip) { | |
834 | cprm.to_skip--; | |
835 | dump_emit(&cprm, "", 1); | |
836 | } | |
e86d35c3 | 837 | file_end_write(cprm.file); |
8032409c | 838 | free_vma_snapshot(&cprm); |
e86d35c3 | 839 | } |
10c28d93 AK |
840 | if (ispipe && core_pipe_limit) |
841 | wait_for_dump_helpers(cprm.file); | |
842 | close_fail: | |
843 | if (cprm.file) | |
844 | filp_close(cprm.file, NULL); | |
845 | fail_dropcount: | |
846 | if (ispipe) | |
847 | atomic_dec(&core_dump_count); | |
848 | fail_unlock: | |
315c6926 | 849 | kfree(argv); |
10c28d93 | 850 | kfree(cn.corename); |
acdedd99 | 851 | coredump_finish(mm, core_dumped); |
10c28d93 AK |
852 | revert_creds(old_cred); |
853 | fail_creds: | |
854 | put_cred(cred); | |
855 | fail: | |
856 | return; | |
857 | } | |
858 | ||
859 | /* | |
860 | * Core dumping helper functions. These are the only things you should | |
861 | * do on a core-file: use only these functions to write out all the | |
862 | * necessary info. | |
863 | */ | |
d0f1088b | 864 | static int __dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
ecc8c772 AV |
865 | { |
866 | struct file *file = cprm->file; | |
2507a4fb AV |
867 | loff_t pos = file->f_pos; |
868 | ssize_t n; | |
2c4cb043 | 869 | if (cprm->written + nr > cprm->limit) |
ecc8c772 | 870 | return 0; |
df0c09c0 JH |
871 | |
872 | ||
873 | if (dump_interrupted()) | |
874 | return 0; | |
875 | n = __kernel_write(file, addr, nr, &pos); | |
876 | if (n != nr) | |
877 | return 0; | |
878 | file->f_pos = pos; | |
879 | cprm->written += n; | |
880 | cprm->pos += n; | |
881 | ||
ecc8c772 AV |
882 | return 1; |
883 | } | |
ecc8c772 | 884 | |
d0f1088b | 885 | static int __dump_skip(struct coredump_params *cprm, size_t nr) |
10c28d93 | 886 | { |
9b56d543 AV |
887 | static char zeroes[PAGE_SIZE]; |
888 | struct file *file = cprm->file; | |
10c28d93 | 889 | if (file->f_op->llseek && file->f_op->llseek != no_llseek) { |
528f827e | 890 | if (dump_interrupted() || |
9b56d543 | 891 | file->f_op->llseek(file, nr, SEEK_CUR) < 0) |
10c28d93 | 892 | return 0; |
1607f09c | 893 | cprm->pos += nr; |
9b56d543 | 894 | return 1; |
10c28d93 | 895 | } else { |
9b56d543 | 896 | while (nr > PAGE_SIZE) { |
d0f1088b | 897 | if (!__dump_emit(cprm, zeroes, PAGE_SIZE)) |
9b56d543 AV |
898 | return 0; |
899 | nr -= PAGE_SIZE; | |
10c28d93 | 900 | } |
d0f1088b | 901 | return __dump_emit(cprm, zeroes, nr); |
10c28d93 | 902 | } |
10c28d93 | 903 | } |
d0f1088b AV |
904 | |
905 | int dump_emit(struct coredump_params *cprm, const void *addr, int nr) | |
906 | { | |
907 | if (cprm->to_skip) { | |
908 | if (!__dump_skip(cprm, cprm->to_skip)) | |
909 | return 0; | |
910 | cprm->to_skip = 0; | |
911 | } | |
912 | return __dump_emit(cprm, addr, nr); | |
913 | } | |
914 | EXPORT_SYMBOL(dump_emit); | |
915 | ||
916 | void dump_skip_to(struct coredump_params *cprm, unsigned long pos) | |
917 | { | |
918 | cprm->to_skip = pos - cprm->pos; | |
919 | } | |
920 | EXPORT_SYMBOL(dump_skip_to); | |
921 | ||
922 | void dump_skip(struct coredump_params *cprm, size_t nr) | |
923 | { | |
924 | cprm->to_skip += nr; | |
925 | } | |
9b56d543 | 926 | EXPORT_SYMBOL(dump_skip); |
22a8cb82 | 927 | |
afc63a97 JH |
928 | #ifdef CONFIG_ELF_CORE |
929 | int dump_user_range(struct coredump_params *cprm, unsigned long start, | |
930 | unsigned long len) | |
931 | { | |
932 | unsigned long addr; | |
933 | ||
934 | for (addr = start; addr < start + len; addr += PAGE_SIZE) { | |
935 | struct page *page; | |
936 | int stop; | |
937 | ||
938 | /* | |
939 | * To avoid having to allocate page tables for virtual address | |
940 | * ranges that have never been used yet, and also to make it | |
941 | * easy to generate sparse core files, use a helper that returns | |
942 | * NULL when encountering an empty page table entry that would | |
943 | * otherwise have been filled with the zero page. | |
944 | */ | |
945 | page = get_dump_page(addr); | |
946 | if (page) { | |
3159ed57 | 947 | void *kaddr = kmap_local_page(page); |
afc63a97 JH |
948 | |
949 | stop = !dump_emit(cprm, kaddr, PAGE_SIZE); | |
3159ed57 | 950 | kunmap_local(kaddr); |
afc63a97 | 951 | put_page(page); |
d0f1088b AV |
952 | if (stop) |
953 | return 0; | |
afc63a97 | 954 | } else { |
d0f1088b | 955 | dump_skip(cprm, PAGE_SIZE); |
afc63a97 | 956 | } |
afc63a97 JH |
957 | } |
958 | return 1; | |
959 | } | |
960 | #endif | |
961 | ||
22a8cb82 AV |
962 | int dump_align(struct coredump_params *cprm, int align) |
963 | { | |
d0f1088b | 964 | unsigned mod = (cprm->pos + cprm->to_skip) & (align - 1); |
22a8cb82 | 965 | if (align & (align - 1)) |
db51242d | 966 | return 0; |
d0f1088b AV |
967 | if (mod) |
968 | cprm->to_skip += align - mod; | |
969 | return 1; | |
22a8cb82 AV |
970 | } |
971 | EXPORT_SYMBOL(dump_align); | |
4d22c75d | 972 | |
429a22e7 JH |
973 | /* |
974 | * The purpose of always_dump_vma() is to make sure that special kernel mappings | |
975 | * that are useful for post-mortem analysis are included in every core dump. | |
976 | * In that way we ensure that the core dump is fully interpretable later | |
977 | * without matching up the same kernel and hardware config to see what PC values | |
978 | * meant. These special mappings include - vDSO, vsyscall, and other | |
979 | * architecture specific mappings | |
980 | */ | |
981 | static bool always_dump_vma(struct vm_area_struct *vma) | |
982 | { | |
983 | /* Any vsyscall mappings? */ | |
984 | if (vma == get_gate_vma(vma->vm_mm)) | |
985 | return true; | |
986 | ||
987 | /* | |
988 | * Assume that all vmas with a .name op should always be dumped. | |
989 | * If this changes, a new vm_ops field can easily be added. | |
990 | */ | |
991 | if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma)) | |
992 | return true; | |
993 | ||
994 | /* | |
995 | * arch_vma_name() returns non-NULL for special architecture mappings, | |
996 | * such as vDSO sections. | |
997 | */ | |
998 | if (arch_vma_name(vma)) | |
999 | return true; | |
1000 | ||
1001 | return false; | |
1002 | } | |
1003 | ||
28f2c9f0 JH |
1004 | #define DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER 1 |
1005 | ||
429a22e7 JH |
1006 | /* |
1007 | * Decide how much of @vma's contents should be included in a core dump. | |
1008 | */ | |
a07279c9 JH |
1009 | static unsigned long vma_dump_size(struct vm_area_struct *vma, |
1010 | unsigned long mm_flags) | |
429a22e7 JH |
1011 | { |
1012 | #define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) | |
1013 | ||
1014 | /* always dump the vdso and vsyscall sections */ | |
1015 | if (always_dump_vma(vma)) | |
1016 | goto whole; | |
1017 | ||
1018 | if (vma->vm_flags & VM_DONTDUMP) | |
1019 | return 0; | |
1020 | ||
1021 | /* support for DAX */ | |
1022 | if (vma_is_dax(vma)) { | |
1023 | if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED)) | |
1024 | goto whole; | |
1025 | if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE)) | |
1026 | goto whole; | |
1027 | return 0; | |
1028 | } | |
1029 | ||
1030 | /* Hugetlb memory check */ | |
1031 | if (is_vm_hugetlb_page(vma)) { | |
1032 | if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) | |
1033 | goto whole; | |
1034 | if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) | |
1035 | goto whole; | |
1036 | return 0; | |
1037 | } | |
1038 | ||
1039 | /* Do not dump I/O mapped devices or special mappings */ | |
1040 | if (vma->vm_flags & VM_IO) | |
1041 | return 0; | |
1042 | ||
1043 | /* By default, dump shared memory if mapped from an anonymous file. */ | |
1044 | if (vma->vm_flags & VM_SHARED) { | |
1045 | if (file_inode(vma->vm_file)->i_nlink == 0 ? | |
1046 | FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) | |
1047 | goto whole; | |
1048 | return 0; | |
1049 | } | |
1050 | ||
1051 | /* Dump segments that have been written to. */ | |
1052 | if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE)) | |
1053 | goto whole; | |
1054 | if (vma->vm_file == NULL) | |
1055 | return 0; | |
1056 | ||
1057 | if (FILTER(MAPPED_PRIVATE)) | |
1058 | goto whole; | |
1059 | ||
1060 | /* | |
1061 | * If this is the beginning of an executable file mapping, | |
1062 | * dump the first page to aid in determining what was mapped here. | |
1063 | */ | |
1064 | if (FILTER(ELF_HEADERS) && | |
28f2c9f0 JH |
1065 | vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { |
1066 | if ((READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0) | |
1067 | return PAGE_SIZE; | |
1068 | ||
1069 | /* | |
1070 | * ELF libraries aren't always executable. | |
1071 | * We'll want to check whether the mapping starts with the ELF | |
1072 | * magic, but not now - we're holding the mmap lock, | |
1073 | * so copy_from_user() doesn't work here. | |
1074 | * Use a placeholder instead, and fix it up later in | |
1075 | * dump_vma_snapshot(). | |
1076 | */ | |
1077 | return DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER; | |
1078 | } | |
429a22e7 JH |
1079 | |
1080 | #undef FILTER | |
1081 | ||
1082 | return 0; | |
1083 | ||
1084 | whole: | |
1085 | return vma->vm_end - vma->vm_start; | |
1086 | } | |
a07279c9 JH |
1087 | |
1088 | static struct vm_area_struct *first_vma(struct task_struct *tsk, | |
1089 | struct vm_area_struct *gate_vma) | |
1090 | { | |
1091 | struct vm_area_struct *ret = tsk->mm->mmap; | |
1092 | ||
1093 | if (ret) | |
1094 | return ret; | |
1095 | return gate_vma; | |
1096 | } | |
1097 | ||
1098 | /* | |
1099 | * Helper function for iterating across a vma list. It ensures that the caller | |
1100 | * will visit `gate_vma' prior to terminating the search. | |
1101 | */ | |
1102 | static struct vm_area_struct *next_vma(struct vm_area_struct *this_vma, | |
1103 | struct vm_area_struct *gate_vma) | |
1104 | { | |
1105 | struct vm_area_struct *ret; | |
1106 | ||
1107 | ret = this_vma->vm_next; | |
1108 | if (ret) | |
1109 | return ret; | |
1110 | if (this_vma == gate_vma) | |
1111 | return NULL; | |
1112 | return gate_vma; | |
1113 | } | |
1114 | ||
8032409c EB |
1115 | static void free_vma_snapshot(struct coredump_params *cprm) |
1116 | { | |
1117 | if (cprm->vma_meta) { | |
1118 | int i; | |
1119 | for (i = 0; i < cprm->vma_count; i++) { | |
1120 | struct file *file = cprm->vma_meta[i].file; | |
1121 | if (file) | |
1122 | fput(file); | |
1123 | } | |
1124 | kvfree(cprm->vma_meta); | |
1125 | cprm->vma_meta = NULL; | |
1126 | } | |
1127 | } | |
1128 | ||
a07279c9 JH |
1129 | /* |
1130 | * Under the mmap_lock, take a snapshot of relevant information about the task's | |
1131 | * VMAs. | |
1132 | */ | |
b2708174 | 1133 | static bool dump_vma_snapshot(struct coredump_params *cprm) |
a07279c9 JH |
1134 | { |
1135 | struct vm_area_struct *vma, *gate_vma; | |
1136 | struct mm_struct *mm = current->mm; | |
1137 | int i; | |
a07279c9 JH |
1138 | |
1139 | /* | |
1140 | * Once the stack expansion code is fixed to not change VMA bounds | |
1141 | * under mmap_lock in read mode, this can be changed to take the | |
1142 | * mmap_lock in read mode. | |
1143 | */ | |
1144 | if (mmap_write_lock_killable(mm)) | |
b2708174 | 1145 | return false; |
a07279c9 | 1146 | |
b2708174 | 1147 | cprm->vma_data_size = 0; |
a07279c9 | 1148 | gate_vma = get_gate_vma(mm); |
b2708174 | 1149 | cprm->vma_count = mm->map_count + (gate_vma ? 1 : 0); |
a07279c9 | 1150 | |
b2708174 EB |
1151 | cprm->vma_meta = kvmalloc_array(cprm->vma_count, sizeof(*cprm->vma_meta), GFP_KERNEL); |
1152 | if (!cprm->vma_meta) { | |
a07279c9 | 1153 | mmap_write_unlock(mm); |
b2708174 | 1154 | return false; |
a07279c9 JH |
1155 | } |
1156 | ||
1157 | for (i = 0, vma = first_vma(current, gate_vma); vma != NULL; | |
1158 | vma = next_vma(vma, gate_vma), i++) { | |
b2708174 | 1159 | struct core_vma_metadata *m = cprm->vma_meta + i; |
a07279c9 JH |
1160 | |
1161 | m->start = vma->vm_start; | |
1162 | m->end = vma->vm_end; | |
1163 | m->flags = vma->vm_flags; | |
1164 | m->dump_size = vma_dump_size(vma, cprm->mm_flags); | |
8032409c EB |
1165 | m->pgoff = vma->vm_pgoff; |
1166 | ||
1167 | m->file = vma->vm_file; | |
1168 | if (m->file) | |
1169 | get_file(m->file); | |
a07279c9 JH |
1170 | } |
1171 | ||
1172 | mmap_write_unlock(mm); | |
1173 | ||
b2708174 EB |
1174 | for (i = 0; i < cprm->vma_count; i++) { |
1175 | struct core_vma_metadata *m = cprm->vma_meta + i; | |
28f2c9f0 JH |
1176 | |
1177 | if (m->dump_size == DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER) { | |
1178 | char elfmag[SELFMAG]; | |
1179 | ||
1180 | if (copy_from_user(elfmag, (void __user *)m->start, SELFMAG) || | |
1181 | memcmp(elfmag, ELFMAG, SELFMAG) != 0) { | |
1182 | m->dump_size = 0; | |
1183 | } else { | |
1184 | m->dump_size = PAGE_SIZE; | |
1185 | } | |
1186 | } | |
1187 | ||
b2708174 | 1188 | cprm->vma_data_size += m->dump_size; |
28f2c9f0 JH |
1189 | } |
1190 | ||
b2708174 | 1191 | return true; |
a07279c9 | 1192 | } |