Commit | Line | Data |
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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> | |
10c28d93 AK |
34 | #include <linux/kmod.h> |
35 | #include <linux/fsnotify.h> | |
36 | #include <linux/fs_struct.h> | |
37 | #include <linux/pipe_fs_i.h> | |
38 | #include <linux/oom.h> | |
39 | #include <linux/compat.h> | |
378c6520 JH |
40 | #include <linux/fs.h> |
41 | #include <linux/path.h> | |
03927c8a | 42 | #include <linux/timekeeping.h> |
f0bc21b2 | 43 | #include <linux/sysctl.h> |
84158b7f | 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 | ||
95c5436a | 56 | static bool dump_vma_snapshot(struct coredump_params *cprm); |
390031c9 | 57 | static void free_vma_snapshot(struct coredump_params *cprm); |
95c5436a | 58 | |
f0bc21b2 XN |
59 | static int core_uses_pid; |
60 | static unsigned int core_pipe_limit; | |
61 | static char core_pattern[CORENAME_MAX_SIZE] = "core"; | |
3ceadcf6 | 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 | 68 | |
3ceadcf6 | 69 | static int expand_corename(struct core_name *cn, int size) |
10c28d93 | 70 | { |
e7fd1549 | 71 | char *corename = krealloc(cn->corename, size, GFP_KERNEL); |
10c28d93 | 72 | |
e7fd1549 | 73 | if (!corename) |
10c28d93 | 74 | return -ENOMEM; |
10c28d93 | 75 | |
3ceadcf6 ON |
76 | if (size > core_name_size) /* racy but harmless */ |
77 | core_name_size = size; | |
78 | ||
79 | cn->size = ksize(corename); | |
e7fd1549 | 80 | cn->corename = corename; |
10c28d93 AK |
81 | return 0; |
82 | } | |
83 | ||
b4176b7c NI |
84 | static __printf(2, 0) int cn_vprintf(struct core_name *cn, const char *fmt, |
85 | va_list arg) | |
10c28d93 | 86 | { |
5fe9d8ca | 87 | int free, need; |
404ca80e | 88 | va_list arg_copy; |
10c28d93 | 89 | |
5fe9d8ca ON |
90 | again: |
91 | free = cn->size - cn->used; | |
404ca80e ED |
92 | |
93 | va_copy(arg_copy, arg); | |
94 | need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy); | |
95 | va_end(arg_copy); | |
96 | ||
5fe9d8ca ON |
97 | if (need < free) { |
98 | cn->used += need; | |
99 | return 0; | |
100 | } | |
10c28d93 | 101 | |
3ceadcf6 | 102 | if (!expand_corename(cn, cn->size + need - free + 1)) |
5fe9d8ca | 103 | goto again; |
10c28d93 | 104 | |
5fe9d8ca | 105 | return -ENOMEM; |
10c28d93 AK |
106 | } |
107 | ||
b4176b7c | 108 | static __printf(2, 3) int cn_printf(struct core_name *cn, const char *fmt, ...) |
bc03c691 ON |
109 | { |
110 | va_list arg; | |
111 | int ret; | |
112 | ||
113 | va_start(arg, fmt); | |
114 | ret = cn_vprintf(cn, fmt, arg); | |
115 | va_end(arg); | |
116 | ||
117 | return ret; | |
118 | } | |
119 | ||
b4176b7c NI |
120 | static __printf(2, 3) |
121 | int cn_esc_printf(struct core_name *cn, const char *fmt, ...) | |
10c28d93 | 122 | { |
923bed03 ON |
123 | int cur = cn->used; |
124 | va_list arg; | |
125 | int ret; | |
126 | ||
127 | va_start(arg, fmt); | |
128 | ret = cn_vprintf(cn, fmt, arg); | |
129 | va_end(arg); | |
130 | ||
ac94b6e3 JH |
131 | if (ret == 0) { |
132 | /* | |
133 | * Ensure that this coredump name component can't cause the | |
134 | * resulting corefile path to consist of a ".." or ".". | |
135 | */ | |
136 | if ((cn->used - cur == 1 && cn->corename[cur] == '.') || | |
137 | (cn->used - cur == 2 && cn->corename[cur] == '.' | |
138 | && cn->corename[cur+1] == '.')) | |
139 | cn->corename[cur] = '!'; | |
140 | ||
141 | /* | |
142 | * Empty names are fishy and could be used to create a "//" in a | |
143 | * corefile name, causing the coredump to happen one directory | |
144 | * level too high. Enforce that all components of the core | |
145 | * pattern are at least one character long. | |
146 | */ | |
147 | if (cn->used == cur) | |
148 | ret = cn_printf(cn, "!"); | |
149 | } | |
150 | ||
923bed03 ON |
151 | for (; cur < cn->used; ++cur) { |
152 | if (cn->corename[cur] == '/') | |
153 | cn->corename[cur] = '!'; | |
154 | } | |
155 | return ret; | |
10c28d93 AK |
156 | } |
157 | ||
f38c85f1 | 158 | static int cn_print_exe_file(struct core_name *cn, bool name_only) |
10c28d93 AK |
159 | { |
160 | struct file *exe_file; | |
f38c85f1 | 161 | char *pathbuf, *path, *ptr; |
10c28d93 AK |
162 | int ret; |
163 | ||
164 | exe_file = get_mm_exe_file(current->mm); | |
923bed03 ON |
165 | if (!exe_file) |
166 | return cn_esc_printf(cn, "%s (path unknown)", current->comm); | |
10c28d93 | 167 | |
0ee931c4 | 168 | pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); |
10c28d93 AK |
169 | if (!pathbuf) { |
170 | ret = -ENOMEM; | |
171 | goto put_exe_file; | |
172 | } | |
173 | ||
9bf39ab2 | 174 | path = file_path(exe_file, pathbuf, PATH_MAX); |
10c28d93 AK |
175 | if (IS_ERR(path)) { |
176 | ret = PTR_ERR(path); | |
177 | goto free_buf; | |
178 | } | |
179 | ||
f38c85f1 LW |
180 | if (name_only) { |
181 | ptr = strrchr(path, '/'); | |
182 | if (ptr) | |
183 | path = ptr + 1; | |
184 | } | |
923bed03 | 185 | ret = cn_esc_printf(cn, "%s", path); |
10c28d93 AK |
186 | |
187 | free_buf: | |
188 | kfree(pathbuf); | |
189 | put_exe_file: | |
190 | fput(exe_file); | |
191 | return ret; | |
192 | } | |
193 | ||
194 | /* format_corename will inspect the pattern parameter, and output a | |
195 | * name into corename, which must have space for at least | |
196 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. | |
197 | */ | |
315c6926 PW |
198 | static int format_corename(struct core_name *cn, struct coredump_params *cprm, |
199 | size_t **argv, int *argc) | |
10c28d93 AK |
200 | { |
201 | const struct cred *cred = current_cred(); | |
202 | const char *pat_ptr = core_pattern; | |
203 | int ispipe = (*pat_ptr == '|'); | |
315c6926 | 204 | bool was_space = false; |
10c28d93 AK |
205 | int pid_in_pattern = 0; |
206 | int err = 0; | |
207 | ||
e7fd1549 | 208 | cn->used = 0; |
3ceadcf6 ON |
209 | cn->corename = NULL; |
210 | if (expand_corename(cn, core_name_size)) | |
10c28d93 | 211 | return -ENOMEM; |
888ffc59 ON |
212 | cn->corename[0] = '\0'; |
213 | ||
315c6926 PW |
214 | if (ispipe) { |
215 | int argvs = sizeof(core_pattern) / 2; | |
216 | (*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL); | |
217 | if (!(*argv)) | |
218 | return -ENOMEM; | |
219 | (*argv)[(*argc)++] = 0; | |
888ffc59 | 220 | ++pat_ptr; |
db973a72 SM |
221 | if (!(*pat_ptr)) |
222 | return -ENOMEM; | |
315c6926 | 223 | } |
10c28d93 AK |
224 | |
225 | /* Repeat as long as we have more pattern to process and more output | |
226 | space */ | |
227 | while (*pat_ptr) { | |
315c6926 PW |
228 | /* |
229 | * Split on spaces before doing template expansion so that | |
230 | * %e and %E don't get split if they have spaces in them | |
231 | */ | |
232 | if (ispipe) { | |
233 | if (isspace(*pat_ptr)) { | |
2bf509d9 MD |
234 | if (cn->used != 0) |
235 | was_space = true; | |
315c6926 PW |
236 | pat_ptr++; |
237 | continue; | |
238 | } else if (was_space) { | |
239 | was_space = false; | |
240 | err = cn_printf(cn, "%c", '\0'); | |
241 | if (err) | |
242 | return err; | |
243 | (*argv)[(*argc)++] = cn->used; | |
244 | } | |
245 | } | |
10c28d93 | 246 | if (*pat_ptr != '%') { |
10c28d93 AK |
247 | err = cn_printf(cn, "%c", *pat_ptr++); |
248 | } else { | |
249 | switch (*++pat_ptr) { | |
250 | /* single % at the end, drop that */ | |
251 | case 0: | |
252 | goto out; | |
253 | /* Double percent, output one percent */ | |
254 | case '%': | |
255 | err = cn_printf(cn, "%c", '%'); | |
256 | break; | |
257 | /* pid */ | |
258 | case 'p': | |
259 | pid_in_pattern = 1; | |
260 | err = cn_printf(cn, "%d", | |
261 | task_tgid_vnr(current)); | |
262 | break; | |
65aafb1e SG |
263 | /* global pid */ |
264 | case 'P': | |
265 | err = cn_printf(cn, "%d", | |
266 | task_tgid_nr(current)); | |
267 | break; | |
b03023ec ON |
268 | case 'i': |
269 | err = cn_printf(cn, "%d", | |
270 | task_pid_vnr(current)); | |
271 | break; | |
272 | case 'I': | |
273 | err = cn_printf(cn, "%d", | |
274 | task_pid_nr(current)); | |
275 | break; | |
10c28d93 AK |
276 | /* uid */ |
277 | case 'u': | |
5202efe5 NI |
278 | err = cn_printf(cn, "%u", |
279 | from_kuid(&init_user_ns, | |
280 | cred->uid)); | |
10c28d93 AK |
281 | break; |
282 | /* gid */ | |
283 | case 'g': | |
5202efe5 NI |
284 | err = cn_printf(cn, "%u", |
285 | from_kgid(&init_user_ns, | |
286 | cred->gid)); | |
10c28d93 | 287 | break; |
12a2b4b2 ON |
288 | case 'd': |
289 | err = cn_printf(cn, "%d", | |
290 | __get_dumpable(cprm->mm_flags)); | |
291 | break; | |
10c28d93 AK |
292 | /* signal that caused the coredump */ |
293 | case 's': | |
b4176b7c NI |
294 | err = cn_printf(cn, "%d", |
295 | cprm->siginfo->si_signo); | |
10c28d93 AK |
296 | break; |
297 | /* UNIX time of coredump */ | |
298 | case 't': { | |
03927c8a AB |
299 | time64_t time; |
300 | ||
301 | time = ktime_get_real_seconds(); | |
302 | err = cn_printf(cn, "%lld", time); | |
10c28d93 AK |
303 | break; |
304 | } | |
305 | /* hostname */ | |
923bed03 | 306 | case 'h': |
10c28d93 | 307 | down_read(&uts_sem); |
923bed03 | 308 | err = cn_esc_printf(cn, "%s", |
10c28d93 AK |
309 | utsname()->nodename); |
310 | up_read(&uts_sem); | |
10c28d93 | 311 | break; |
f38c85f1 | 312 | /* executable, could be changed by prctl PR_SET_NAME etc */ |
923bed03 ON |
313 | case 'e': |
314 | err = cn_esc_printf(cn, "%s", current->comm); | |
10c28d93 | 315 | break; |
f38c85f1 LW |
316 | /* file name of executable */ |
317 | case 'f': | |
318 | err = cn_print_exe_file(cn, true); | |
319 | break; | |
10c28d93 | 320 | case 'E': |
f38c85f1 | 321 | err = cn_print_exe_file(cn, false); |
10c28d93 AK |
322 | break; |
323 | /* core limit size */ | |
324 | case 'c': | |
325 | err = cn_printf(cn, "%lu", | |
326 | rlimit(RLIMIT_CORE)); | |
327 | break; | |
328 | default: | |
329 | break; | |
330 | } | |
331 | ++pat_ptr; | |
332 | } | |
333 | ||
334 | if (err) | |
335 | return err; | |
336 | } | |
337 | ||
888ffc59 | 338 | out: |
10c28d93 AK |
339 | /* Backward compatibility with core_uses_pid: |
340 | * | |
341 | * If core_pattern does not include a %p (as is the default) | |
342 | * and core_uses_pid is set, then .%pid will be appended to | |
343 | * the filename. Do not do this for piped commands. */ | |
344 | if (!ispipe && !pid_in_pattern && core_uses_pid) { | |
345 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); | |
346 | if (err) | |
347 | return err; | |
348 | } | |
10c28d93 AK |
349 | return ispipe; |
350 | } | |
351 | ||
752dc970 | 352 | static int zap_process(struct task_struct *start, int exit_code) |
10c28d93 AK |
353 | { |
354 | struct task_struct *t; | |
355 | int nr = 0; | |
356 | ||
9a95f78e | 357 | /* Allow SIGKILL, see prepare_signal() */ |
2f824d4d | 358 | start->signal->flags = SIGNAL_GROUP_EXIT; |
10c28d93 AK |
359 | start->signal->group_exit_code = exit_code; |
360 | start->signal->group_stop_count = 0; | |
361 | ||
d61ba589 | 362 | for_each_thread(start, t) { |
10c28d93 | 363 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
92307383 | 364 | if (t != current && !(t->flags & PF_POSTCOREDUMP)) { |
10c28d93 AK |
365 | sigaddset(&t->pending.signal, SIGKILL); |
366 | signal_wake_up(t, 1); | |
367 | nr++; | |
368 | } | |
d61ba589 | 369 | } |
10c28d93 AK |
370 | |
371 | return nr; | |
372 | } | |
373 | ||
0258b5fd | 374 | static int zap_threads(struct task_struct *tsk, |
403bad72 | 375 | struct core_state *core_state, int exit_code) |
10c28d93 | 376 | { |
49697335 | 377 | struct signal_struct *signal = tsk->signal; |
10c28d93 AK |
378 | int nr = -EAGAIN; |
379 | ||
380 | spin_lock_irq(&tsk->sighand->siglock); | |
49697335 EB |
381 | if (!(signal->flags & SIGNAL_GROUP_EXIT) && !signal->group_exec_task) { |
382 | signal->core_state = core_state; | |
752dc970 | 383 | nr = zap_process(tsk, exit_code); |
403bad72 | 384 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING); |
0258b5fd EB |
385 | tsk->flags |= PF_DUMPCORE; |
386 | atomic_set(&core_state->nr_threads, nr); | |
10c28d93 AK |
387 | } |
388 | spin_unlock_irq(&tsk->sighand->siglock); | |
10c28d93 AK |
389 | return nr; |
390 | } | |
391 | ||
392 | static int coredump_wait(int exit_code, struct core_state *core_state) | |
393 | { | |
394 | struct task_struct *tsk = current; | |
10c28d93 AK |
395 | int core_waiters = -EBUSY; |
396 | ||
397 | init_completion(&core_state->startup); | |
398 | core_state->dumper.task = tsk; | |
399 | core_state->dumper.next = NULL; | |
400 | ||
0258b5fd | 401 | core_waiters = zap_threads(tsk, core_state, exit_code); |
10c28d93 AK |
402 | if (core_waiters > 0) { |
403 | struct core_thread *ptr; | |
404 | ||
f5d39b02 PZ |
405 | wait_for_completion_state(&core_state->startup, |
406 | TASK_UNINTERRUPTIBLE|TASK_FREEZABLE); | |
10c28d93 AK |
407 | /* |
408 | * Wait for all the threads to become inactive, so that | |
409 | * all the thread context (extended register state, like | |
410 | * fpu etc) gets copied to the memory. | |
411 | */ | |
412 | ptr = core_state->dumper.next; | |
413 | while (ptr != NULL) { | |
f9fc8cad | 414 | wait_task_inactive(ptr->task, TASK_ANY); |
10c28d93 AK |
415 | ptr = ptr->next; |
416 | } | |
417 | } | |
418 | ||
419 | return core_waiters; | |
420 | } | |
421 | ||
0258b5fd | 422 | static void coredump_finish(bool core_dumped) |
10c28d93 AK |
423 | { |
424 | struct core_thread *curr, *next; | |
425 | struct task_struct *task; | |
426 | ||
6cd8f0ac | 427 | spin_lock_irq(¤t->sighand->siglock); |
acdedd99 ON |
428 | if (core_dumped && !__fatal_signal_pending(current)) |
429 | current->signal->group_exit_code |= 0x80; | |
0258b5fd EB |
430 | next = current->signal->core_state->dumper.next; |
431 | current->signal->core_state = NULL; | |
6cd8f0ac ON |
432 | spin_unlock_irq(¤t->sighand->siglock); |
433 | ||
10c28d93 AK |
434 | while ((curr = next) != NULL) { |
435 | next = curr->next; | |
436 | task = curr->task; | |
437 | /* | |
92307383 | 438 | * see coredump_task_exit(), curr->task must not see |
10c28d93 AK |
439 | * ->task == NULL before we read ->next. |
440 | */ | |
441 | smp_mb(); | |
442 | curr->task = NULL; | |
443 | wake_up_process(task); | |
444 | } | |
10c28d93 AK |
445 | } |
446 | ||
528f827e ON |
447 | static bool dump_interrupted(void) |
448 | { | |
449 | /* | |
450 | * SIGKILL or freezing() interrupt the coredumping. Perhaps we | |
451 | * can do try_to_freeze() and check __fatal_signal_pending(), | |
452 | * but then we need to teach dump_write() to restart and clear | |
453 | * TIF_SIGPENDING. | |
454 | */ | |
06af8679 | 455 | return fatal_signal_pending(current) || freezing(current); |
528f827e ON |
456 | } |
457 | ||
10c28d93 AK |
458 | static void wait_for_dump_helpers(struct file *file) |
459 | { | |
de32ec4c | 460 | struct pipe_inode_info *pipe = file->private_data; |
10c28d93 AK |
461 | |
462 | pipe_lock(pipe); | |
463 | pipe->readers++; | |
464 | pipe->writers--; | |
0ddad21d | 465 | wake_up_interruptible_sync(&pipe->rd_wait); |
dc7ee2aa ON |
466 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
467 | pipe_unlock(pipe); | |
10c28d93 | 468 | |
dc7ee2aa ON |
469 | /* |
470 | * We actually want wait_event_freezable() but then we need | |
471 | * to clear TIF_SIGPENDING and improve dump_interrupted(). | |
472 | */ | |
0ddad21d | 473 | wait_event_interruptible(pipe->rd_wait, pipe->readers == 1); |
10c28d93 | 474 | |
dc7ee2aa | 475 | pipe_lock(pipe); |
10c28d93 AK |
476 | pipe->readers--; |
477 | pipe->writers++; | |
478 | pipe_unlock(pipe); | |
10c28d93 AK |
479 | } |
480 | ||
481 | /* | |
482 | * umh_pipe_setup | |
483 | * helper function to customize the process used | |
484 | * to collect the core in userspace. Specifically | |
485 | * it sets up a pipe and installs it as fd 0 (stdin) | |
486 | * for the process. Returns 0 on success, or | |
487 | * PTR_ERR on failure. | |
488 | * Note that it also sets the core limit to 1. This | |
489 | * is a special value that we use to trap recursive | |
490 | * core dumps | |
491 | */ | |
492 | static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) | |
493 | { | |
494 | struct file *files[2]; | |
495 | struct coredump_params *cp = (struct coredump_params *)info->data; | |
496 | int err = create_pipe_files(files, 0); | |
497 | if (err) | |
498 | return err; | |
499 | ||
500 | cp->file = files[1]; | |
501 | ||
45525b26 AV |
502 | err = replace_fd(0, files[0], 0); |
503 | fput(files[0]); | |
10c28d93 AK |
504 | /* and disallow core files too */ |
505 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; | |
506 | ||
45525b26 | 507 | return err; |
10c28d93 AK |
508 | } |
509 | ||
ae7795bc | 510 | void do_coredump(const kernel_siginfo_t *siginfo) |
10c28d93 AK |
511 | { |
512 | struct core_state core_state; | |
513 | struct core_name cn; | |
514 | struct mm_struct *mm = current->mm; | |
515 | struct linux_binfmt * binfmt; | |
516 | const struct cred *old_cred; | |
517 | struct cred *cred; | |
518 | int retval = 0; | |
10c28d93 | 519 | int ispipe; |
315c6926 PW |
520 | size_t *argv = NULL; |
521 | int argc = 0; | |
fbb18169 JH |
522 | /* require nonrelative corefile path and be extra careful */ |
523 | bool need_suid_safe = false; | |
acdedd99 | 524 | bool core_dumped = false; |
10c28d93 AK |
525 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
526 | struct coredump_params cprm = { | |
5ab1c309 | 527 | .siginfo = siginfo, |
541880d9 | 528 | .regs = signal_pt_regs(), |
10c28d93 AK |
529 | .limit = rlimit(RLIMIT_CORE), |
530 | /* | |
531 | * We must use the same mm->flags while dumping core to avoid | |
532 | * inconsistency of bit flags, since this flag is not protected | |
533 | * by any locks. | |
534 | */ | |
535 | .mm_flags = mm->flags, | |
95c5436a | 536 | .vma_meta = NULL, |
10c28d93 AK |
537 | }; |
538 | ||
5ab1c309 | 539 | audit_core_dumps(siginfo->si_signo); |
10c28d93 AK |
540 | |
541 | binfmt = mm->binfmt; | |
542 | if (!binfmt || !binfmt->core_dump) | |
543 | goto fail; | |
544 | if (!__get_dumpable(cprm.mm_flags)) | |
545 | goto fail; | |
546 | ||
547 | cred = prepare_creds(); | |
548 | if (!cred) | |
549 | goto fail; | |
550 | /* | |
551 | * We cannot trust fsuid as being the "true" uid of the process | |
552 | * nor do we know its entire history. We only know it was tainted | |
553 | * so we dump it as root in mode 2, and only into a controlled | |
554 | * environment (pipe handler or fully qualified path). | |
555 | */ | |
e579d2c2 | 556 | if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) { |
10c28d93 | 557 | /* Setuid core dump mode */ |
10c28d93 | 558 | cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ |
fbb18169 | 559 | need_suid_safe = true; |
10c28d93 AK |
560 | } |
561 | ||
5ab1c309 | 562 | retval = coredump_wait(siginfo->si_signo, &core_state); |
10c28d93 AK |
563 | if (retval < 0) |
564 | goto fail_creds; | |
565 | ||
566 | old_cred = override_creds(cred); | |
567 | ||
315c6926 | 568 | ispipe = format_corename(&cn, &cprm, &argv, &argc); |
10c28d93 | 569 | |
fb96c475 | 570 | if (ispipe) { |
315c6926 | 571 | int argi; |
10c28d93 AK |
572 | int dump_count; |
573 | char **helper_argv; | |
907ed132 | 574 | struct subprocess_info *sub_info; |
10c28d93 AK |
575 | |
576 | if (ispipe < 0) { | |
577 | printk(KERN_WARNING "format_corename failed\n"); | |
578 | printk(KERN_WARNING "Aborting core\n"); | |
e7fd1549 | 579 | goto fail_unlock; |
10c28d93 AK |
580 | } |
581 | ||
582 | if (cprm.limit == 1) { | |
583 | /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. | |
584 | * | |
585 | * Normally core limits are irrelevant to pipes, since | |
586 | * we're not writing to the file system, but we use | |
fcbc32bc | 587 | * cprm.limit of 1 here as a special value, this is a |
10c28d93 AK |
588 | * consistent way to catch recursive crashes. |
589 | * We can still crash if the core_pattern binary sets | |
590 | * RLIM_CORE = !1, but it runs as root, and can do | |
591 | * lots of stupid things. | |
592 | * | |
593 | * Note that we use task_tgid_vnr here to grab the pid | |
594 | * of the process group leader. That way we get the | |
595 | * right pid if a thread in a multi-threaded | |
596 | * core_pattern process dies. | |
597 | */ | |
598 | printk(KERN_WARNING | |
599 | "Process %d(%s) has RLIMIT_CORE set to 1\n", | |
600 | task_tgid_vnr(current), current->comm); | |
601 | printk(KERN_WARNING "Aborting core\n"); | |
602 | goto fail_unlock; | |
603 | } | |
604 | cprm.limit = RLIM_INFINITY; | |
605 | ||
606 | dump_count = atomic_inc_return(&core_dump_count); | |
607 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { | |
608 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", | |
609 | task_tgid_vnr(current), current->comm); | |
610 | printk(KERN_WARNING "Skipping core dump\n"); | |
611 | goto fail_dropcount; | |
612 | } | |
613 | ||
315c6926 PW |
614 | helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), |
615 | GFP_KERNEL); | |
10c28d93 AK |
616 | if (!helper_argv) { |
617 | printk(KERN_WARNING "%s failed to allocate memory\n", | |
618 | __func__); | |
619 | goto fail_dropcount; | |
620 | } | |
315c6926 PW |
621 | for (argi = 0; argi < argc; argi++) |
622 | helper_argv[argi] = cn.corename + argv[argi]; | |
623 | helper_argv[argi] = NULL; | |
10c28d93 | 624 | |
907ed132 LDM |
625 | retval = -ENOMEM; |
626 | sub_info = call_usermodehelper_setup(helper_argv[0], | |
627 | helper_argv, NULL, GFP_KERNEL, | |
628 | umh_pipe_setup, NULL, &cprm); | |
629 | if (sub_info) | |
630 | retval = call_usermodehelper_exec(sub_info, | |
631 | UMH_WAIT_EXEC); | |
632 | ||
315c6926 | 633 | kfree(helper_argv); |
10c28d93 | 634 | if (retval) { |
888ffc59 | 635 | printk(KERN_INFO "Core dump to |%s pipe failed\n", |
10c28d93 AK |
636 | cn.corename); |
637 | goto close_fail; | |
fb96c475 | 638 | } |
10c28d93 | 639 | } else { |
643fe55a | 640 | struct user_namespace *mnt_userns; |
10c28d93 | 641 | struct inode *inode; |
378c6520 JH |
642 | int open_flags = O_CREAT | O_RDWR | O_NOFOLLOW | |
643 | O_LARGEFILE | O_EXCL; | |
10c28d93 AK |
644 | |
645 | if (cprm.limit < binfmt->min_coredump) | |
646 | goto fail_unlock; | |
647 | ||
fbb18169 | 648 | if (need_suid_safe && cn.corename[0] != '/') { |
10c28d93 AK |
649 | printk(KERN_WARNING "Pid %d(%s) can only dump core "\ |
650 | "to fully qualified path!\n", | |
651 | task_tgid_vnr(current), current->comm); | |
652 | printk(KERN_WARNING "Skipping core dump\n"); | |
653 | goto fail_unlock; | |
654 | } | |
655 | ||
fbb18169 JH |
656 | /* |
657 | * Unlink the file if it exists unless this is a SUID | |
658 | * binary - in that case, we're running around with root | |
659 | * privs and don't want to unlink another user's coredump. | |
660 | */ | |
661 | if (!need_suid_safe) { | |
fbb18169 JH |
662 | /* |
663 | * If it doesn't exist, that's fine. If there's some | |
664 | * other problem, we'll catch it at the filp_open(). | |
665 | */ | |
96271654 | 666 | do_unlinkat(AT_FDCWD, getname_kernel(cn.corename)); |
fbb18169 JH |
667 | } |
668 | ||
669 | /* | |
670 | * There is a race between unlinking and creating the | |
671 | * file, but if that causes an EEXIST here, that's | |
672 | * fine - another process raced with us while creating | |
673 | * the corefile, and the other process won. To userspace, | |
674 | * what matters is that at least one of the two processes | |
675 | * writes its coredump successfully, not which one. | |
676 | */ | |
378c6520 JH |
677 | if (need_suid_safe) { |
678 | /* | |
679 | * Using user namespaces, normal user tasks can change | |
680 | * their current->fs->root to point to arbitrary | |
681 | * directories. Since the intention of the "only dump | |
682 | * with a fully qualified path" rule is to control where | |
683 | * coredumps may be placed using root privileges, | |
684 | * current->fs->root must not be used. Instead, use the | |
685 | * root directory of init_task. | |
686 | */ | |
687 | struct path root; | |
688 | ||
689 | task_lock(&init_task); | |
690 | get_fs_root(init_task.fs, &root); | |
691 | task_unlock(&init_task); | |
ffb37ca3 AV |
692 | cprm.file = file_open_root(&root, cn.corename, |
693 | open_flags, 0600); | |
378c6520 JH |
694 | path_put(&root); |
695 | } else { | |
696 | cprm.file = filp_open(cn.corename, open_flags, 0600); | |
697 | } | |
10c28d93 AK |
698 | if (IS_ERR(cprm.file)) |
699 | goto fail_unlock; | |
700 | ||
496ad9aa | 701 | inode = file_inode(cprm.file); |
10c28d93 AK |
702 | if (inode->i_nlink > 1) |
703 | goto close_fail; | |
704 | if (d_unhashed(cprm.file->f_path.dentry)) | |
705 | goto close_fail; | |
706 | /* | |
707 | * AK: actually i see no reason to not allow this for named | |
708 | * pipes etc, but keep the previous behaviour for now. | |
709 | */ | |
710 | if (!S_ISREG(inode->i_mode)) | |
711 | goto close_fail; | |
712 | /* | |
40f705a7 JH |
713 | * Don't dump core if the filesystem changed owner or mode |
714 | * of the file during file creation. This is an issue when | |
715 | * a process dumps core while its cwd is e.g. on a vfat | |
716 | * filesystem. | |
10c28d93 | 717 | */ |
643fe55a | 718 | mnt_userns = file_mnt_user_ns(cprm.file); |
dbd9d6f8 DO |
719 | if (!uid_eq(i_uid_into_mnt(mnt_userns, inode), |
720 | current_fsuid())) { | |
721 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n", | |
722 | cn.corename); | |
10c28d93 | 723 | goto close_fail; |
dbd9d6f8 DO |
724 | } |
725 | if ((inode->i_mode & 0677) != 0600) { | |
726 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file permissions\n", | |
727 | cn.corename); | |
40f705a7 | 728 | goto close_fail; |
dbd9d6f8 | 729 | } |
86cc0584 | 730 | if (!(cprm.file->f_mode & FMODE_CAN_WRITE)) |
10c28d93 | 731 | goto close_fail; |
643fe55a CB |
732 | if (do_truncate(mnt_userns, cprm.file->f_path.dentry, |
733 | 0, 0, cprm.file)) | |
10c28d93 AK |
734 | goto close_fail; |
735 | } | |
736 | ||
737 | /* get us an unshared descriptor table; almost always a no-op */ | |
c39ab6de | 738 | /* The cell spufs coredump code reads the file descriptor tables */ |
1f702603 | 739 | retval = unshare_files(); |
10c28d93 AK |
740 | if (retval) |
741 | goto close_fail; | |
e86d35c3 | 742 | if (!dump_interrupted()) { |
3740d93e LC |
743 | /* |
744 | * umh disabled with CONFIG_STATIC_USERMODEHELPER_PATH="" would | |
745 | * have this set to NULL. | |
746 | */ | |
747 | if (!cprm.file) { | |
748 | pr_info("Core dump to |%s disabled\n", cn.corename); | |
749 | goto close_fail; | |
750 | } | |
95c5436a EB |
751 | if (!dump_vma_snapshot(&cprm)) |
752 | goto close_fail; | |
753 | ||
e86d35c3 AV |
754 | file_start_write(cprm.file); |
755 | core_dumped = binfmt->core_dump(&cprm); | |
d0f1088b AV |
756 | /* |
757 | * Ensures that file size is big enough to contain the current | |
758 | * file postion. This prevents gdb from complaining about | |
759 | * a truncated file if the last "write" to the file was | |
760 | * dump_skip. | |
761 | */ | |
762 | if (cprm.to_skip) { | |
763 | cprm.to_skip--; | |
764 | dump_emit(&cprm, "", 1); | |
765 | } | |
e86d35c3 | 766 | file_end_write(cprm.file); |
390031c9 | 767 | free_vma_snapshot(&cprm); |
e86d35c3 | 768 | } |
10c28d93 AK |
769 | if (ispipe && core_pipe_limit) |
770 | wait_for_dump_helpers(cprm.file); | |
771 | close_fail: | |
772 | if (cprm.file) | |
773 | filp_close(cprm.file, NULL); | |
774 | fail_dropcount: | |
775 | if (ispipe) | |
776 | atomic_dec(&core_dump_count); | |
777 | fail_unlock: | |
315c6926 | 778 | kfree(argv); |
10c28d93 | 779 | kfree(cn.corename); |
0258b5fd | 780 | coredump_finish(core_dumped); |
10c28d93 AK |
781 | revert_creds(old_cred); |
782 | fail_creds: | |
783 | put_cred(cred); | |
784 | fail: | |
785 | return; | |
786 | } | |
787 | ||
788 | /* | |
789 | * Core dumping helper functions. These are the only things you should | |
790 | * do on a core-file: use only these functions to write out all the | |
791 | * necessary info. | |
792 | */ | |
d0f1088b | 793 | static int __dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
ecc8c772 AV |
794 | { |
795 | struct file *file = cprm->file; | |
2507a4fb AV |
796 | loff_t pos = file->f_pos; |
797 | ssize_t n; | |
2c4cb043 | 798 | if (cprm->written + nr > cprm->limit) |
ecc8c772 | 799 | return 0; |
df0c09c0 JH |
800 | |
801 | ||
802 | if (dump_interrupted()) | |
803 | return 0; | |
804 | n = __kernel_write(file, addr, nr, &pos); | |
805 | if (n != nr) | |
806 | return 0; | |
807 | file->f_pos = pos; | |
808 | cprm->written += n; | |
809 | cprm->pos += n; | |
810 | ||
ecc8c772 AV |
811 | return 1; |
812 | } | |
ecc8c772 | 813 | |
d0f1088b | 814 | static int __dump_skip(struct coredump_params *cprm, size_t nr) |
10c28d93 | 815 | { |
9b56d543 AV |
816 | static char zeroes[PAGE_SIZE]; |
817 | struct file *file = cprm->file; | |
4e3299ea | 818 | if (file->f_mode & FMODE_LSEEK) { |
528f827e | 819 | if (dump_interrupted() || |
4e3299ea | 820 | vfs_llseek(file, nr, SEEK_CUR) < 0) |
10c28d93 | 821 | return 0; |
1607f09c | 822 | cprm->pos += nr; |
9b56d543 | 823 | return 1; |
10c28d93 | 824 | } else { |
9b56d543 | 825 | while (nr > PAGE_SIZE) { |
d0f1088b | 826 | if (!__dump_emit(cprm, zeroes, PAGE_SIZE)) |
9b56d543 AV |
827 | return 0; |
828 | nr -= PAGE_SIZE; | |
10c28d93 | 829 | } |
d0f1088b | 830 | return __dump_emit(cprm, zeroes, nr); |
10c28d93 | 831 | } |
10c28d93 | 832 | } |
d0f1088b | 833 | |
06bbaa6d AV |
834 | static int dump_emit_page(struct coredump_params *cprm, struct page *page) |
835 | { | |
836 | struct bio_vec bvec = { | |
837 | .bv_page = page, | |
838 | .bv_offset = 0, | |
839 | .bv_len = PAGE_SIZE, | |
840 | }; | |
841 | struct iov_iter iter; | |
842 | struct file *file = cprm->file; | |
4f526fef | 843 | loff_t pos; |
06bbaa6d AV |
844 | ssize_t n; |
845 | ||
846 | if (cprm->to_skip) { | |
847 | if (!__dump_skip(cprm, cprm->to_skip)) | |
848 | return 0; | |
849 | cprm->to_skip = 0; | |
850 | } | |
851 | if (cprm->written + PAGE_SIZE > cprm->limit) | |
852 | return 0; | |
853 | if (dump_interrupted()) | |
854 | return 0; | |
4f526fef | 855 | pos = file->f_pos; |
06bbaa6d AV |
856 | iov_iter_bvec(&iter, WRITE, &bvec, 1, PAGE_SIZE); |
857 | n = __kernel_write_iter(cprm->file, &iter, &pos); | |
858 | if (n != PAGE_SIZE) | |
859 | return 0; | |
860 | file->f_pos = pos; | |
861 | cprm->written += PAGE_SIZE; | |
862 | cprm->pos += PAGE_SIZE; | |
863 | ||
864 | return 1; | |
865 | } | |
866 | ||
d0f1088b AV |
867 | int dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
868 | { | |
869 | if (cprm->to_skip) { | |
870 | if (!__dump_skip(cprm, cprm->to_skip)) | |
871 | return 0; | |
872 | cprm->to_skip = 0; | |
873 | } | |
874 | return __dump_emit(cprm, addr, nr); | |
875 | } | |
876 | EXPORT_SYMBOL(dump_emit); | |
877 | ||
878 | void dump_skip_to(struct coredump_params *cprm, unsigned long pos) | |
879 | { | |
880 | cprm->to_skip = pos - cprm->pos; | |
881 | } | |
882 | EXPORT_SYMBOL(dump_skip_to); | |
883 | ||
884 | void dump_skip(struct coredump_params *cprm, size_t nr) | |
885 | { | |
886 | cprm->to_skip += nr; | |
887 | } | |
9b56d543 | 888 | EXPORT_SYMBOL(dump_skip); |
22a8cb82 | 889 | |
afc63a97 JH |
890 | #ifdef CONFIG_ELF_CORE |
891 | int dump_user_range(struct coredump_params *cprm, unsigned long start, | |
892 | unsigned long len) | |
893 | { | |
894 | unsigned long addr; | |
895 | ||
896 | for (addr = start; addr < start + len; addr += PAGE_SIZE) { | |
897 | struct page *page; | |
afc63a97 JH |
898 | |
899 | /* | |
900 | * To avoid having to allocate page tables for virtual address | |
901 | * ranges that have never been used yet, and also to make it | |
902 | * easy to generate sparse core files, use a helper that returns | |
903 | * NULL when encountering an empty page table entry that would | |
904 | * otherwise have been filled with the zero page. | |
905 | */ | |
906 | page = get_dump_page(addr); | |
907 | if (page) { | |
06bbaa6d | 908 | int stop = !dump_emit_page(cprm, page); |
afc63a97 | 909 | put_page(page); |
d0f1088b AV |
910 | if (stop) |
911 | return 0; | |
afc63a97 | 912 | } else { |
d0f1088b | 913 | dump_skip(cprm, PAGE_SIZE); |
afc63a97 | 914 | } |
afc63a97 JH |
915 | } |
916 | return 1; | |
917 | } | |
918 | #endif | |
919 | ||
22a8cb82 AV |
920 | int dump_align(struct coredump_params *cprm, int align) |
921 | { | |
d0f1088b | 922 | unsigned mod = (cprm->pos + cprm->to_skip) & (align - 1); |
22a8cb82 | 923 | if (align & (align - 1)) |
db51242d | 924 | return 0; |
d0f1088b AV |
925 | if (mod) |
926 | cprm->to_skip += align - mod; | |
927 | return 1; | |
22a8cb82 AV |
928 | } |
929 | EXPORT_SYMBOL(dump_align); | |
4d22c75d | 930 | |
f0bc21b2 XN |
931 | #ifdef CONFIG_SYSCTL |
932 | ||
933 | void validate_coredump_safety(void) | |
934 | { | |
935 | if (suid_dumpable == SUID_DUMP_ROOT && | |
936 | core_pattern[0] != '/' && core_pattern[0] != '|') { | |
937 | pr_warn( | |
938 | "Unsafe core_pattern used with fs.suid_dumpable=2.\n" | |
939 | "Pipe handler or fully qualified core dump path required.\n" | |
940 | "Set kernel.core_pattern before fs.suid_dumpable.\n" | |
941 | ); | |
942 | } | |
943 | } | |
944 | ||
945 | static int proc_dostring_coredump(struct ctl_table *table, int write, | |
946 | void *buffer, size_t *lenp, loff_t *ppos) | |
947 | { | |
948 | int error = proc_dostring(table, write, buffer, lenp, ppos); | |
949 | ||
950 | if (!error) | |
951 | validate_coredump_safety(); | |
952 | return error; | |
953 | } | |
954 | ||
955 | static struct ctl_table coredump_sysctls[] = { | |
956 | { | |
957 | .procname = "core_uses_pid", | |
958 | .data = &core_uses_pid, | |
959 | .maxlen = sizeof(int), | |
960 | .mode = 0644, | |
961 | .proc_handler = proc_dointvec, | |
962 | }, | |
963 | { | |
964 | .procname = "core_pattern", | |
965 | .data = core_pattern, | |
966 | .maxlen = CORENAME_MAX_SIZE, | |
967 | .mode = 0644, | |
968 | .proc_handler = proc_dostring_coredump, | |
969 | }, | |
970 | { | |
971 | .procname = "core_pipe_limit", | |
972 | .data = &core_pipe_limit, | |
973 | .maxlen = sizeof(unsigned int), | |
974 | .mode = 0644, | |
975 | .proc_handler = proc_dointvec, | |
976 | }, | |
977 | { } | |
978 | }; | |
979 | ||
980 | static int __init init_fs_coredump_sysctls(void) | |
981 | { | |
982 | register_sysctl_init("kernel", coredump_sysctls); | |
983 | return 0; | |
984 | } | |
985 | fs_initcall(init_fs_coredump_sysctls); | |
986 | #endif /* CONFIG_SYSCTL */ | |
987 | ||
429a22e7 JH |
988 | /* |
989 | * The purpose of always_dump_vma() is to make sure that special kernel mappings | |
990 | * that are useful for post-mortem analysis are included in every core dump. | |
991 | * In that way we ensure that the core dump is fully interpretable later | |
992 | * without matching up the same kernel and hardware config to see what PC values | |
993 | * meant. These special mappings include - vDSO, vsyscall, and other | |
994 | * architecture specific mappings | |
995 | */ | |
996 | static bool always_dump_vma(struct vm_area_struct *vma) | |
997 | { | |
998 | /* Any vsyscall mappings? */ | |
999 | if (vma == get_gate_vma(vma->vm_mm)) | |
1000 | return true; | |
1001 | ||
1002 | /* | |
1003 | * Assume that all vmas with a .name op should always be dumped. | |
1004 | * If this changes, a new vm_ops field can easily be added. | |
1005 | */ | |
1006 | if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma)) | |
1007 | return true; | |
1008 | ||
1009 | /* | |
1010 | * arch_vma_name() returns non-NULL for special architecture mappings, | |
1011 | * such as vDSO sections. | |
1012 | */ | |
1013 | if (arch_vma_name(vma)) | |
1014 | return true; | |
1015 | ||
1016 | return false; | |
1017 | } | |
1018 | ||
84158b7f JH |
1019 | #define DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER 1 |
1020 | ||
429a22e7 JH |
1021 | /* |
1022 | * Decide how much of @vma's contents should be included in a core dump. | |
1023 | */ | |
a07279c9 JH |
1024 | static unsigned long vma_dump_size(struct vm_area_struct *vma, |
1025 | unsigned long mm_flags) | |
429a22e7 JH |
1026 | { |
1027 | #define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) | |
1028 | ||
1029 | /* always dump the vdso and vsyscall sections */ | |
1030 | if (always_dump_vma(vma)) | |
1031 | goto whole; | |
1032 | ||
1033 | if (vma->vm_flags & VM_DONTDUMP) | |
1034 | return 0; | |
1035 | ||
1036 | /* support for DAX */ | |
1037 | if (vma_is_dax(vma)) { | |
1038 | if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED)) | |
1039 | goto whole; | |
1040 | if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE)) | |
1041 | goto whole; | |
1042 | return 0; | |
1043 | } | |
1044 | ||
1045 | /* Hugetlb memory check */ | |
1046 | if (is_vm_hugetlb_page(vma)) { | |
1047 | if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) | |
1048 | goto whole; | |
1049 | if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) | |
1050 | goto whole; | |
1051 | return 0; | |
1052 | } | |
1053 | ||
1054 | /* Do not dump I/O mapped devices or special mappings */ | |
1055 | if (vma->vm_flags & VM_IO) | |
1056 | return 0; | |
1057 | ||
1058 | /* By default, dump shared memory if mapped from an anonymous file. */ | |
1059 | if (vma->vm_flags & VM_SHARED) { | |
1060 | if (file_inode(vma->vm_file)->i_nlink == 0 ? | |
1061 | FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) | |
1062 | goto whole; | |
1063 | return 0; | |
1064 | } | |
1065 | ||
1066 | /* Dump segments that have been written to. */ | |
1067 | if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE)) | |
1068 | goto whole; | |
1069 | if (vma->vm_file == NULL) | |
1070 | return 0; | |
1071 | ||
1072 | if (FILTER(MAPPED_PRIVATE)) | |
1073 | goto whole; | |
1074 | ||
1075 | /* | |
1076 | * If this is the beginning of an executable file mapping, | |
1077 | * dump the first page to aid in determining what was mapped here. | |
1078 | */ | |
1079 | if (FILTER(ELF_HEADERS) && | |
84158b7f JH |
1080 | vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { |
1081 | if ((READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0) | |
1082 | return PAGE_SIZE; | |
1083 | ||
1084 | /* | |
1085 | * ELF libraries aren't always executable. | |
1086 | * We'll want to check whether the mapping starts with the ELF | |
1087 | * magic, but not now - we're holding the mmap lock, | |
1088 | * so copy_from_user() doesn't work here. | |
1089 | * Use a placeholder instead, and fix it up later in | |
1090 | * dump_vma_snapshot(). | |
1091 | */ | |
1092 | return DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER; | |
1093 | } | |
429a22e7 JH |
1094 | |
1095 | #undef FILTER | |
1096 | ||
1097 | return 0; | |
1098 | ||
1099 | whole: | |
1100 | return vma->vm_end - vma->vm_start; | |
1101 | } | |
a07279c9 | 1102 | |
a07279c9 JH |
1103 | /* |
1104 | * Helper function for iterating across a vma list. It ensures that the caller | |
1105 | * will visit `gate_vma' prior to terminating the search. | |
1106 | */ | |
182ea1d7 MWO |
1107 | static struct vm_area_struct *coredump_next_vma(struct ma_state *mas, |
1108 | struct vm_area_struct *vma, | |
a07279c9 JH |
1109 | struct vm_area_struct *gate_vma) |
1110 | { | |
182ea1d7 | 1111 | if (gate_vma && (vma == gate_vma)) |
a07279c9 | 1112 | return NULL; |
182ea1d7 MWO |
1113 | |
1114 | vma = mas_next(mas, ULONG_MAX); | |
1115 | if (vma) | |
1116 | return vma; | |
a07279c9 JH |
1117 | return gate_vma; |
1118 | } | |
1119 | ||
390031c9 EB |
1120 | static void free_vma_snapshot(struct coredump_params *cprm) |
1121 | { | |
1122 | if (cprm->vma_meta) { | |
1123 | int i; | |
1124 | for (i = 0; i < cprm->vma_count; i++) { | |
1125 | struct file *file = cprm->vma_meta[i].file; | |
1126 | if (file) | |
1127 | fput(file); | |
1128 | } | |
1129 | kvfree(cprm->vma_meta); | |
1130 | cprm->vma_meta = NULL; | |
1131 | } | |
1132 | } | |
1133 | ||
a07279c9 JH |
1134 | /* |
1135 | * Under the mmap_lock, take a snapshot of relevant information about the task's | |
1136 | * VMAs. | |
1137 | */ | |
95c5436a | 1138 | static bool dump_vma_snapshot(struct coredump_params *cprm) |
a07279c9 | 1139 | { |
182ea1d7 | 1140 | struct vm_area_struct *gate_vma, *vma = NULL; |
a07279c9 | 1141 | struct mm_struct *mm = current->mm; |
182ea1d7 MWO |
1142 | MA_STATE(mas, &mm->mm_mt, 0, 0); |
1143 | int i = 0; | |
a07279c9 JH |
1144 | |
1145 | /* | |
1146 | * Once the stack expansion code is fixed to not change VMA bounds | |
1147 | * under mmap_lock in read mode, this can be changed to take the | |
1148 | * mmap_lock in read mode. | |
1149 | */ | |
1150 | if (mmap_write_lock_killable(mm)) | |
95c5436a | 1151 | return false; |
a07279c9 | 1152 | |
95c5436a | 1153 | cprm->vma_data_size = 0; |
a07279c9 | 1154 | gate_vma = get_gate_vma(mm); |
95c5436a | 1155 | cprm->vma_count = mm->map_count + (gate_vma ? 1 : 0); |
a07279c9 | 1156 | |
95c5436a EB |
1157 | cprm->vma_meta = kvmalloc_array(cprm->vma_count, sizeof(*cprm->vma_meta), GFP_KERNEL); |
1158 | if (!cprm->vma_meta) { | |
a07279c9 | 1159 | mmap_write_unlock(mm); |
95c5436a | 1160 | return false; |
a07279c9 JH |
1161 | } |
1162 | ||
182ea1d7 | 1163 | while ((vma = coredump_next_vma(&mas, vma, gate_vma)) != NULL) { |
95c5436a | 1164 | struct core_vma_metadata *m = cprm->vma_meta + i; |
a07279c9 JH |
1165 | |
1166 | m->start = vma->vm_start; | |
1167 | m->end = vma->vm_end; | |
1168 | m->flags = vma->vm_flags; | |
1169 | m->dump_size = vma_dump_size(vma, cprm->mm_flags); | |
390031c9 | 1170 | m->pgoff = vma->vm_pgoff; |
390031c9 EB |
1171 | m->file = vma->vm_file; |
1172 | if (m->file) | |
1173 | get_file(m->file); | |
182ea1d7 | 1174 | i++; |
a07279c9 JH |
1175 | } |
1176 | ||
1177 | mmap_write_unlock(mm); | |
1178 | ||
95c5436a EB |
1179 | for (i = 0; i < cprm->vma_count; i++) { |
1180 | struct core_vma_metadata *m = cprm->vma_meta + i; | |
84158b7f JH |
1181 | |
1182 | if (m->dump_size == DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER) { | |
1183 | char elfmag[SELFMAG]; | |
1184 | ||
1185 | if (copy_from_user(elfmag, (void __user *)m->start, SELFMAG) || | |
1186 | memcmp(elfmag, ELFMAG, SELFMAG) != 0) { | |
1187 | m->dump_size = 0; | |
1188 | } else { | |
1189 | m->dump_size = PAGE_SIZE; | |
1190 | } | |
1191 | } | |
1192 | ||
95c5436a | 1193 | cprm->vma_data_size += m->dump_size; |
84158b7f JH |
1194 | } |
1195 | ||
95c5436a | 1196 | return true; |
a07279c9 | 1197 | } |