| 1 | // SPDX-License-Identifier: GPL-2.0 |
| 2 | #include <linux/slab.h> |
| 3 | #include <linux/file.h> |
| 4 | #include <linux/fdtable.h> |
| 5 | #include <linux/freezer.h> |
| 6 | #include <linux/mm.h> |
| 7 | #include <linux/stat.h> |
| 8 | #include <linux/fcntl.h> |
| 9 | #include <linux/swap.h> |
| 10 | #include <linux/ctype.h> |
| 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> |
| 20 | #include <linux/coredump.h> |
| 21 | #include <linux/sched/coredump.h> |
| 22 | #include <linux/sched/signal.h> |
| 23 | #include <linux/sched/task_stack.h> |
| 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/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> |
| 40 | #include <linux/fs.h> |
| 41 | #include <linux/path.h> |
| 42 | #include <linux/timekeeping.h> |
| 43 | #include <linux/sysctl.h> |
| 44 | #include <linux/elf.h> |
| 45 | |
| 46 | #include <linux/uaccess.h> |
| 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 | |
| 56 | static bool dump_vma_snapshot(struct coredump_params *cprm); |
| 57 | static void free_vma_snapshot(struct coredump_params *cprm); |
| 58 | |
| 59 | static int core_uses_pid; |
| 60 | static unsigned int core_pipe_limit; |
| 61 | static char core_pattern[CORENAME_MAX_SIZE] = "core"; |
| 62 | static int core_name_size = CORENAME_MAX_SIZE; |
| 63 | |
| 64 | struct core_name { |
| 65 | char *corename; |
| 66 | int used, size; |
| 67 | }; |
| 68 | |
| 69 | static int expand_corename(struct core_name *cn, int size) |
| 70 | { |
| 71 | char *corename; |
| 72 | |
| 73 | size = kmalloc_size_roundup(size); |
| 74 | corename = krealloc(cn->corename, size, GFP_KERNEL); |
| 75 | |
| 76 | if (!corename) |
| 77 | return -ENOMEM; |
| 78 | |
| 79 | if (size > core_name_size) /* racy but harmless */ |
| 80 | core_name_size = size; |
| 81 | |
| 82 | cn->size = size; |
| 83 | cn->corename = corename; |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static __printf(2, 0) int cn_vprintf(struct core_name *cn, const char *fmt, |
| 88 | va_list arg) |
| 89 | { |
| 90 | int free, need; |
| 91 | va_list arg_copy; |
| 92 | |
| 93 | again: |
| 94 | free = cn->size - cn->used; |
| 95 | |
| 96 | va_copy(arg_copy, arg); |
| 97 | need = vsnprintf(cn->corename + cn->used, free, fmt, arg_copy); |
| 98 | va_end(arg_copy); |
| 99 | |
| 100 | if (need < free) { |
| 101 | cn->used += need; |
| 102 | return 0; |
| 103 | } |
| 104 | |
| 105 | if (!expand_corename(cn, cn->size + need - free + 1)) |
| 106 | goto again; |
| 107 | |
| 108 | return -ENOMEM; |
| 109 | } |
| 110 | |
| 111 | static __printf(2, 3) int cn_printf(struct core_name *cn, const char *fmt, ...) |
| 112 | { |
| 113 | va_list arg; |
| 114 | int ret; |
| 115 | |
| 116 | va_start(arg, fmt); |
| 117 | ret = cn_vprintf(cn, fmt, arg); |
| 118 | va_end(arg); |
| 119 | |
| 120 | return ret; |
| 121 | } |
| 122 | |
| 123 | static __printf(2, 3) |
| 124 | int cn_esc_printf(struct core_name *cn, const char *fmt, ...) |
| 125 | { |
| 126 | int cur = cn->used; |
| 127 | va_list arg; |
| 128 | int ret; |
| 129 | |
| 130 | va_start(arg, fmt); |
| 131 | ret = cn_vprintf(cn, fmt, arg); |
| 132 | va_end(arg); |
| 133 | |
| 134 | if (ret == 0) { |
| 135 | /* |
| 136 | * Ensure that this coredump name component can't cause the |
| 137 | * resulting corefile path to consist of a ".." or ".". |
| 138 | */ |
| 139 | if ((cn->used - cur == 1 && cn->corename[cur] == '.') || |
| 140 | (cn->used - cur == 2 && cn->corename[cur] == '.' |
| 141 | && cn->corename[cur+1] == '.')) |
| 142 | cn->corename[cur] = '!'; |
| 143 | |
| 144 | /* |
| 145 | * Empty names are fishy and could be used to create a "//" in a |
| 146 | * corefile name, causing the coredump to happen one directory |
| 147 | * level too high. Enforce that all components of the core |
| 148 | * pattern are at least one character long. |
| 149 | */ |
| 150 | if (cn->used == cur) |
| 151 | ret = cn_printf(cn, "!"); |
| 152 | } |
| 153 | |
| 154 | for (; cur < cn->used; ++cur) { |
| 155 | if (cn->corename[cur] == '/') |
| 156 | cn->corename[cur] = '!'; |
| 157 | } |
| 158 | return ret; |
| 159 | } |
| 160 | |
| 161 | static int cn_print_exe_file(struct core_name *cn, bool name_only) |
| 162 | { |
| 163 | struct file *exe_file; |
| 164 | char *pathbuf, *path, *ptr; |
| 165 | int ret; |
| 166 | |
| 167 | exe_file = get_mm_exe_file(current->mm); |
| 168 | if (!exe_file) |
| 169 | return cn_esc_printf(cn, "%s (path unknown)", current->comm); |
| 170 | |
| 171 | pathbuf = kmalloc(PATH_MAX, GFP_KERNEL); |
| 172 | if (!pathbuf) { |
| 173 | ret = -ENOMEM; |
| 174 | goto put_exe_file; |
| 175 | } |
| 176 | |
| 177 | path = file_path(exe_file, pathbuf, PATH_MAX); |
| 178 | if (IS_ERR(path)) { |
| 179 | ret = PTR_ERR(path); |
| 180 | goto free_buf; |
| 181 | } |
| 182 | |
| 183 | if (name_only) { |
| 184 | ptr = strrchr(path, '/'); |
| 185 | if (ptr) |
| 186 | path = ptr + 1; |
| 187 | } |
| 188 | ret = cn_esc_printf(cn, "%s", path); |
| 189 | |
| 190 | free_buf: |
| 191 | kfree(pathbuf); |
| 192 | put_exe_file: |
| 193 | fput(exe_file); |
| 194 | return ret; |
| 195 | } |
| 196 | |
| 197 | /* format_corename will inspect the pattern parameter, and output a |
| 198 | * name into corename, which must have space for at least |
| 199 | * CORENAME_MAX_SIZE bytes plus one byte for the zero terminator. |
| 200 | */ |
| 201 | static int format_corename(struct core_name *cn, struct coredump_params *cprm, |
| 202 | size_t **argv, int *argc) |
| 203 | { |
| 204 | const struct cred *cred = current_cred(); |
| 205 | const char *pat_ptr = core_pattern; |
| 206 | int ispipe = (*pat_ptr == '|'); |
| 207 | bool was_space = false; |
| 208 | int pid_in_pattern = 0; |
| 209 | int err = 0; |
| 210 | |
| 211 | cn->used = 0; |
| 212 | cn->corename = NULL; |
| 213 | if (expand_corename(cn, core_name_size)) |
| 214 | return -ENOMEM; |
| 215 | cn->corename[0] = '\0'; |
| 216 | |
| 217 | if (ispipe) { |
| 218 | int argvs = sizeof(core_pattern) / 2; |
| 219 | (*argv) = kmalloc_array(argvs, sizeof(**argv), GFP_KERNEL); |
| 220 | if (!(*argv)) |
| 221 | return -ENOMEM; |
| 222 | (*argv)[(*argc)++] = 0; |
| 223 | ++pat_ptr; |
| 224 | if (!(*pat_ptr)) |
| 225 | return -ENOMEM; |
| 226 | } |
| 227 | |
| 228 | /* Repeat as long as we have more pattern to process and more output |
| 229 | space */ |
| 230 | while (*pat_ptr) { |
| 231 | /* |
| 232 | * Split on spaces before doing template expansion so that |
| 233 | * %e and %E don't get split if they have spaces in them |
| 234 | */ |
| 235 | if (ispipe) { |
| 236 | if (isspace(*pat_ptr)) { |
| 237 | if (cn->used != 0) |
| 238 | was_space = true; |
| 239 | pat_ptr++; |
| 240 | continue; |
| 241 | } else if (was_space) { |
| 242 | was_space = false; |
| 243 | err = cn_printf(cn, "%c", '\0'); |
| 244 | if (err) |
| 245 | return err; |
| 246 | (*argv)[(*argc)++] = cn->used; |
| 247 | } |
| 248 | } |
| 249 | if (*pat_ptr != '%') { |
| 250 | err = cn_printf(cn, "%c", *pat_ptr++); |
| 251 | } else { |
| 252 | switch (*++pat_ptr) { |
| 253 | /* single % at the end, drop that */ |
| 254 | case 0: |
| 255 | goto out; |
| 256 | /* Double percent, output one percent */ |
| 257 | case '%': |
| 258 | err = cn_printf(cn, "%c", '%'); |
| 259 | break; |
| 260 | /* pid */ |
| 261 | case 'p': |
| 262 | pid_in_pattern = 1; |
| 263 | err = cn_printf(cn, "%d", |
| 264 | task_tgid_vnr(current)); |
| 265 | break; |
| 266 | /* global pid */ |
| 267 | case 'P': |
| 268 | err = cn_printf(cn, "%d", |
| 269 | task_tgid_nr(current)); |
| 270 | break; |
| 271 | case 'i': |
| 272 | err = cn_printf(cn, "%d", |
| 273 | task_pid_vnr(current)); |
| 274 | break; |
| 275 | case 'I': |
| 276 | err = cn_printf(cn, "%d", |
| 277 | task_pid_nr(current)); |
| 278 | break; |
| 279 | /* uid */ |
| 280 | case 'u': |
| 281 | err = cn_printf(cn, "%u", |
| 282 | from_kuid(&init_user_ns, |
| 283 | cred->uid)); |
| 284 | break; |
| 285 | /* gid */ |
| 286 | case 'g': |
| 287 | err = cn_printf(cn, "%u", |
| 288 | from_kgid(&init_user_ns, |
| 289 | cred->gid)); |
| 290 | break; |
| 291 | case 'd': |
| 292 | err = cn_printf(cn, "%d", |
| 293 | __get_dumpable(cprm->mm_flags)); |
| 294 | break; |
| 295 | /* signal that caused the coredump */ |
| 296 | case 's': |
| 297 | err = cn_printf(cn, "%d", |
| 298 | cprm->siginfo->si_signo); |
| 299 | break; |
| 300 | /* UNIX time of coredump */ |
| 301 | case 't': { |
| 302 | time64_t time; |
| 303 | |
| 304 | time = ktime_get_real_seconds(); |
| 305 | err = cn_printf(cn, "%lld", time); |
| 306 | break; |
| 307 | } |
| 308 | /* hostname */ |
| 309 | case 'h': |
| 310 | down_read(&uts_sem); |
| 311 | err = cn_esc_printf(cn, "%s", |
| 312 | utsname()->nodename); |
| 313 | up_read(&uts_sem); |
| 314 | break; |
| 315 | /* executable, could be changed by prctl PR_SET_NAME etc */ |
| 316 | case 'e': |
| 317 | err = cn_esc_printf(cn, "%s", current->comm); |
| 318 | break; |
| 319 | /* file name of executable */ |
| 320 | case 'f': |
| 321 | err = cn_print_exe_file(cn, true); |
| 322 | break; |
| 323 | case 'E': |
| 324 | err = cn_print_exe_file(cn, false); |
| 325 | break; |
| 326 | /* core limit size */ |
| 327 | case 'c': |
| 328 | err = cn_printf(cn, "%lu", |
| 329 | rlimit(RLIMIT_CORE)); |
| 330 | break; |
| 331 | /* CPU the task ran on */ |
| 332 | case 'C': |
| 333 | err = cn_printf(cn, "%d", cprm->cpu); |
| 334 | break; |
| 335 | default: |
| 336 | break; |
| 337 | } |
| 338 | ++pat_ptr; |
| 339 | } |
| 340 | |
| 341 | if (err) |
| 342 | return err; |
| 343 | } |
| 344 | |
| 345 | out: |
| 346 | /* Backward compatibility with core_uses_pid: |
| 347 | * |
| 348 | * If core_pattern does not include a %p (as is the default) |
| 349 | * and core_uses_pid is set, then .%pid will be appended to |
| 350 | * the filename. Do not do this for piped commands. */ |
| 351 | if (!ispipe && !pid_in_pattern && core_uses_pid) { |
| 352 | err = cn_printf(cn, ".%d", task_tgid_vnr(current)); |
| 353 | if (err) |
| 354 | return err; |
| 355 | } |
| 356 | return ispipe; |
| 357 | } |
| 358 | |
| 359 | static int zap_process(struct task_struct *start, int exit_code) |
| 360 | { |
| 361 | struct task_struct *t; |
| 362 | int nr = 0; |
| 363 | |
| 364 | /* Allow SIGKILL, see prepare_signal() */ |
| 365 | start->signal->flags = SIGNAL_GROUP_EXIT; |
| 366 | start->signal->group_exit_code = exit_code; |
| 367 | start->signal->group_stop_count = 0; |
| 368 | |
| 369 | for_each_thread(start, t) { |
| 370 | task_clear_jobctl_pending(t, JOBCTL_PENDING_MASK); |
| 371 | if (t != current && !(t->flags & PF_POSTCOREDUMP)) { |
| 372 | sigaddset(&t->pending.signal, SIGKILL); |
| 373 | signal_wake_up(t, 1); |
| 374 | nr++; |
| 375 | } |
| 376 | } |
| 377 | |
| 378 | return nr; |
| 379 | } |
| 380 | |
| 381 | static int zap_threads(struct task_struct *tsk, |
| 382 | struct core_state *core_state, int exit_code) |
| 383 | { |
| 384 | struct signal_struct *signal = tsk->signal; |
| 385 | int nr = -EAGAIN; |
| 386 | |
| 387 | spin_lock_irq(&tsk->sighand->siglock); |
| 388 | if (!(signal->flags & SIGNAL_GROUP_EXIT) && !signal->group_exec_task) { |
| 389 | signal->core_state = core_state; |
| 390 | nr = zap_process(tsk, exit_code); |
| 391 | clear_tsk_thread_flag(tsk, TIF_SIGPENDING); |
| 392 | tsk->flags |= PF_DUMPCORE; |
| 393 | atomic_set(&core_state->nr_threads, nr); |
| 394 | } |
| 395 | spin_unlock_irq(&tsk->sighand->siglock); |
| 396 | return nr; |
| 397 | } |
| 398 | |
| 399 | static int coredump_wait(int exit_code, struct core_state *core_state) |
| 400 | { |
| 401 | struct task_struct *tsk = current; |
| 402 | int core_waiters = -EBUSY; |
| 403 | |
| 404 | init_completion(&core_state->startup); |
| 405 | core_state->dumper.task = tsk; |
| 406 | core_state->dumper.next = NULL; |
| 407 | |
| 408 | core_waiters = zap_threads(tsk, core_state, exit_code); |
| 409 | if (core_waiters > 0) { |
| 410 | struct core_thread *ptr; |
| 411 | |
| 412 | wait_for_completion_state(&core_state->startup, |
| 413 | TASK_UNINTERRUPTIBLE|TASK_FREEZABLE); |
| 414 | /* |
| 415 | * Wait for all the threads to become inactive, so that |
| 416 | * all the thread context (extended register state, like |
| 417 | * fpu etc) gets copied to the memory. |
| 418 | */ |
| 419 | ptr = core_state->dumper.next; |
| 420 | while (ptr != NULL) { |
| 421 | wait_task_inactive(ptr->task, TASK_ANY); |
| 422 | ptr = ptr->next; |
| 423 | } |
| 424 | } |
| 425 | |
| 426 | return core_waiters; |
| 427 | } |
| 428 | |
| 429 | static void coredump_finish(bool core_dumped) |
| 430 | { |
| 431 | struct core_thread *curr, *next; |
| 432 | struct task_struct *task; |
| 433 | |
| 434 | spin_lock_irq(¤t->sighand->siglock); |
| 435 | if (core_dumped && !__fatal_signal_pending(current)) |
| 436 | current->signal->group_exit_code |= 0x80; |
| 437 | next = current->signal->core_state->dumper.next; |
| 438 | current->signal->core_state = NULL; |
| 439 | spin_unlock_irq(¤t->sighand->siglock); |
| 440 | |
| 441 | while ((curr = next) != NULL) { |
| 442 | next = curr->next; |
| 443 | task = curr->task; |
| 444 | /* |
| 445 | * see coredump_task_exit(), curr->task must not see |
| 446 | * ->task == NULL before we read ->next. |
| 447 | */ |
| 448 | smp_mb(); |
| 449 | curr->task = NULL; |
| 450 | wake_up_process(task); |
| 451 | } |
| 452 | } |
| 453 | |
| 454 | static bool dump_interrupted(void) |
| 455 | { |
| 456 | /* |
| 457 | * SIGKILL or freezing() interrupt the coredumping. Perhaps we |
| 458 | * can do try_to_freeze() and check __fatal_signal_pending(), |
| 459 | * but then we need to teach dump_write() to restart and clear |
| 460 | * TIF_SIGPENDING. |
| 461 | */ |
| 462 | return fatal_signal_pending(current) || freezing(current); |
| 463 | } |
| 464 | |
| 465 | static void wait_for_dump_helpers(struct file *file) |
| 466 | { |
| 467 | struct pipe_inode_info *pipe = file->private_data; |
| 468 | |
| 469 | pipe_lock(pipe); |
| 470 | pipe->readers++; |
| 471 | pipe->writers--; |
| 472 | wake_up_interruptible_sync(&pipe->rd_wait); |
| 473 | kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); |
| 474 | pipe_unlock(pipe); |
| 475 | |
| 476 | /* |
| 477 | * We actually want wait_event_freezable() but then we need |
| 478 | * to clear TIF_SIGPENDING and improve dump_interrupted(). |
| 479 | */ |
| 480 | wait_event_interruptible(pipe->rd_wait, pipe->readers == 1); |
| 481 | |
| 482 | pipe_lock(pipe); |
| 483 | pipe->readers--; |
| 484 | pipe->writers++; |
| 485 | pipe_unlock(pipe); |
| 486 | } |
| 487 | |
| 488 | /* |
| 489 | * umh_pipe_setup |
| 490 | * helper function to customize the process used |
| 491 | * to collect the core in userspace. Specifically |
| 492 | * it sets up a pipe and installs it as fd 0 (stdin) |
| 493 | * for the process. Returns 0 on success, or |
| 494 | * PTR_ERR on failure. |
| 495 | * Note that it also sets the core limit to 1. This |
| 496 | * is a special value that we use to trap recursive |
| 497 | * core dumps |
| 498 | */ |
| 499 | static int umh_pipe_setup(struct subprocess_info *info, struct cred *new) |
| 500 | { |
| 501 | struct file *files[2]; |
| 502 | struct coredump_params *cp = (struct coredump_params *)info->data; |
| 503 | int err = create_pipe_files(files, 0); |
| 504 | if (err) |
| 505 | return err; |
| 506 | |
| 507 | cp->file = files[1]; |
| 508 | |
| 509 | err = replace_fd(0, files[0], 0); |
| 510 | fput(files[0]); |
| 511 | /* and disallow core files too */ |
| 512 | current->signal->rlim[RLIMIT_CORE] = (struct rlimit){1, 1}; |
| 513 | |
| 514 | return err; |
| 515 | } |
| 516 | |
| 517 | void do_coredump(const kernel_siginfo_t *siginfo) |
| 518 | { |
| 519 | struct core_state core_state; |
| 520 | struct core_name cn; |
| 521 | struct mm_struct *mm = current->mm; |
| 522 | struct linux_binfmt * binfmt; |
| 523 | const struct cred *old_cred; |
| 524 | struct cred *cred; |
| 525 | int retval = 0; |
| 526 | int ispipe; |
| 527 | size_t *argv = NULL; |
| 528 | int argc = 0; |
| 529 | /* require nonrelative corefile path and be extra careful */ |
| 530 | bool need_suid_safe = false; |
| 531 | bool core_dumped = false; |
| 532 | static atomic_t core_dump_count = ATOMIC_INIT(0); |
| 533 | struct coredump_params cprm = { |
| 534 | .siginfo = siginfo, |
| 535 | .limit = rlimit(RLIMIT_CORE), |
| 536 | /* |
| 537 | * We must use the same mm->flags while dumping core to avoid |
| 538 | * inconsistency of bit flags, since this flag is not protected |
| 539 | * by any locks. |
| 540 | */ |
| 541 | .mm_flags = mm->flags, |
| 542 | .vma_meta = NULL, |
| 543 | .cpu = raw_smp_processor_id(), |
| 544 | }; |
| 545 | |
| 546 | audit_core_dumps(siginfo->si_signo); |
| 547 | |
| 548 | binfmt = mm->binfmt; |
| 549 | if (!binfmt || !binfmt->core_dump) |
| 550 | goto fail; |
| 551 | if (!__get_dumpable(cprm.mm_flags)) |
| 552 | goto fail; |
| 553 | |
| 554 | cred = prepare_creds(); |
| 555 | if (!cred) |
| 556 | goto fail; |
| 557 | /* |
| 558 | * We cannot trust fsuid as being the "true" uid of the process |
| 559 | * nor do we know its entire history. We only know it was tainted |
| 560 | * so we dump it as root in mode 2, and only into a controlled |
| 561 | * environment (pipe handler or fully qualified path). |
| 562 | */ |
| 563 | if (__get_dumpable(cprm.mm_flags) == SUID_DUMP_ROOT) { |
| 564 | /* Setuid core dump mode */ |
| 565 | cred->fsuid = GLOBAL_ROOT_UID; /* Dump root private */ |
| 566 | need_suid_safe = true; |
| 567 | } |
| 568 | |
| 569 | retval = coredump_wait(siginfo->si_signo, &core_state); |
| 570 | if (retval < 0) |
| 571 | goto fail_creds; |
| 572 | |
| 573 | old_cred = override_creds(cred); |
| 574 | |
| 575 | ispipe = format_corename(&cn, &cprm, &argv, &argc); |
| 576 | |
| 577 | if (ispipe) { |
| 578 | int argi; |
| 579 | int dump_count; |
| 580 | char **helper_argv; |
| 581 | struct subprocess_info *sub_info; |
| 582 | |
| 583 | if (ispipe < 0) { |
| 584 | printk(KERN_WARNING "format_corename failed\n"); |
| 585 | printk(KERN_WARNING "Aborting core\n"); |
| 586 | goto fail_unlock; |
| 587 | } |
| 588 | |
| 589 | if (cprm.limit == 1) { |
| 590 | /* See umh_pipe_setup() which sets RLIMIT_CORE = 1. |
| 591 | * |
| 592 | * Normally core limits are irrelevant to pipes, since |
| 593 | * we're not writing to the file system, but we use |
| 594 | * cprm.limit of 1 here as a special value, this is a |
| 595 | * consistent way to catch recursive crashes. |
| 596 | * We can still crash if the core_pattern binary sets |
| 597 | * RLIM_CORE = !1, but it runs as root, and can do |
| 598 | * lots of stupid things. |
| 599 | * |
| 600 | * Note that we use task_tgid_vnr here to grab the pid |
| 601 | * of the process group leader. That way we get the |
| 602 | * right pid if a thread in a multi-threaded |
| 603 | * core_pattern process dies. |
| 604 | */ |
| 605 | printk(KERN_WARNING |
| 606 | "Process %d(%s) has RLIMIT_CORE set to 1\n", |
| 607 | task_tgid_vnr(current), current->comm); |
| 608 | printk(KERN_WARNING "Aborting core\n"); |
| 609 | goto fail_unlock; |
| 610 | } |
| 611 | cprm.limit = RLIM_INFINITY; |
| 612 | |
| 613 | dump_count = atomic_inc_return(&core_dump_count); |
| 614 | if (core_pipe_limit && (core_pipe_limit < dump_count)) { |
| 615 | printk(KERN_WARNING "Pid %d(%s) over core_pipe_limit\n", |
| 616 | task_tgid_vnr(current), current->comm); |
| 617 | printk(KERN_WARNING "Skipping core dump\n"); |
| 618 | goto fail_dropcount; |
| 619 | } |
| 620 | |
| 621 | helper_argv = kmalloc_array(argc + 1, sizeof(*helper_argv), |
| 622 | GFP_KERNEL); |
| 623 | if (!helper_argv) { |
| 624 | printk(KERN_WARNING "%s failed to allocate memory\n", |
| 625 | __func__); |
| 626 | goto fail_dropcount; |
| 627 | } |
| 628 | for (argi = 0; argi < argc; argi++) |
| 629 | helper_argv[argi] = cn.corename + argv[argi]; |
| 630 | helper_argv[argi] = NULL; |
| 631 | |
| 632 | retval = -ENOMEM; |
| 633 | sub_info = call_usermodehelper_setup(helper_argv[0], |
| 634 | helper_argv, NULL, GFP_KERNEL, |
| 635 | umh_pipe_setup, NULL, &cprm); |
| 636 | if (sub_info) |
| 637 | retval = call_usermodehelper_exec(sub_info, |
| 638 | UMH_WAIT_EXEC); |
| 639 | |
| 640 | kfree(helper_argv); |
| 641 | if (retval) { |
| 642 | printk(KERN_INFO "Core dump to |%s pipe failed\n", |
| 643 | cn.corename); |
| 644 | goto close_fail; |
| 645 | } |
| 646 | } else { |
| 647 | struct mnt_idmap *idmap; |
| 648 | struct inode *inode; |
| 649 | int open_flags = O_CREAT | O_RDWR | O_NOFOLLOW | |
| 650 | O_LARGEFILE | O_EXCL; |
| 651 | |
| 652 | if (cprm.limit < binfmt->min_coredump) |
| 653 | goto fail_unlock; |
| 654 | |
| 655 | if (need_suid_safe && cn.corename[0] != '/') { |
| 656 | printk(KERN_WARNING "Pid %d(%s) can only dump core "\ |
| 657 | "to fully qualified path!\n", |
| 658 | task_tgid_vnr(current), current->comm); |
| 659 | printk(KERN_WARNING "Skipping core dump\n"); |
| 660 | goto fail_unlock; |
| 661 | } |
| 662 | |
| 663 | /* |
| 664 | * Unlink the file if it exists unless this is a SUID |
| 665 | * binary - in that case, we're running around with root |
| 666 | * privs and don't want to unlink another user's coredump. |
| 667 | */ |
| 668 | if (!need_suid_safe) { |
| 669 | /* |
| 670 | * If it doesn't exist, that's fine. If there's some |
| 671 | * other problem, we'll catch it at the filp_open(). |
| 672 | */ |
| 673 | do_unlinkat(AT_FDCWD, getname_kernel(cn.corename)); |
| 674 | } |
| 675 | |
| 676 | /* |
| 677 | * There is a race between unlinking and creating the |
| 678 | * file, but if that causes an EEXIST here, that's |
| 679 | * fine - another process raced with us while creating |
| 680 | * the corefile, and the other process won. To userspace, |
| 681 | * what matters is that at least one of the two processes |
| 682 | * writes its coredump successfully, not which one. |
| 683 | */ |
| 684 | if (need_suid_safe) { |
| 685 | /* |
| 686 | * Using user namespaces, normal user tasks can change |
| 687 | * their current->fs->root to point to arbitrary |
| 688 | * directories. Since the intention of the "only dump |
| 689 | * with a fully qualified path" rule is to control where |
| 690 | * coredumps may be placed using root privileges, |
| 691 | * current->fs->root must not be used. Instead, use the |
| 692 | * root directory of init_task. |
| 693 | */ |
| 694 | struct path root; |
| 695 | |
| 696 | task_lock(&init_task); |
| 697 | get_fs_root(init_task.fs, &root); |
| 698 | task_unlock(&init_task); |
| 699 | cprm.file = file_open_root(&root, cn.corename, |
| 700 | open_flags, 0600); |
| 701 | path_put(&root); |
| 702 | } else { |
| 703 | cprm.file = filp_open(cn.corename, open_flags, 0600); |
| 704 | } |
| 705 | if (IS_ERR(cprm.file)) |
| 706 | goto fail_unlock; |
| 707 | |
| 708 | inode = file_inode(cprm.file); |
| 709 | if (inode->i_nlink > 1) |
| 710 | goto close_fail; |
| 711 | if (d_unhashed(cprm.file->f_path.dentry)) |
| 712 | goto close_fail; |
| 713 | /* |
| 714 | * AK: actually i see no reason to not allow this for named |
| 715 | * pipes etc, but keep the previous behaviour for now. |
| 716 | */ |
| 717 | if (!S_ISREG(inode->i_mode)) |
| 718 | goto close_fail; |
| 719 | /* |
| 720 | * Don't dump core if the filesystem changed owner or mode |
| 721 | * of the file during file creation. This is an issue when |
| 722 | * a process dumps core while its cwd is e.g. on a vfat |
| 723 | * filesystem. |
| 724 | */ |
| 725 | idmap = file_mnt_idmap(cprm.file); |
| 726 | if (!vfsuid_eq_kuid(i_uid_into_vfsuid(idmap, inode), |
| 727 | current_fsuid())) { |
| 728 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file owner\n", |
| 729 | cn.corename); |
| 730 | goto close_fail; |
| 731 | } |
| 732 | if ((inode->i_mode & 0677) != 0600) { |
| 733 | pr_info_ratelimited("Core dump to %s aborted: cannot preserve file permissions\n", |
| 734 | cn.corename); |
| 735 | goto close_fail; |
| 736 | } |
| 737 | if (!(cprm.file->f_mode & FMODE_CAN_WRITE)) |
| 738 | goto close_fail; |
| 739 | if (do_truncate(idmap, cprm.file->f_path.dentry, |
| 740 | 0, 0, cprm.file)) |
| 741 | goto close_fail; |
| 742 | } |
| 743 | |
| 744 | /* get us an unshared descriptor table; almost always a no-op */ |
| 745 | /* The cell spufs coredump code reads the file descriptor tables */ |
| 746 | retval = unshare_files(); |
| 747 | if (retval) |
| 748 | goto close_fail; |
| 749 | if (!dump_interrupted()) { |
| 750 | /* |
| 751 | * umh disabled with CONFIG_STATIC_USERMODEHELPER_PATH="" would |
| 752 | * have this set to NULL. |
| 753 | */ |
| 754 | if (!cprm.file) { |
| 755 | pr_info("Core dump to |%s disabled\n", cn.corename); |
| 756 | goto close_fail; |
| 757 | } |
| 758 | if (!dump_vma_snapshot(&cprm)) |
| 759 | goto close_fail; |
| 760 | |
| 761 | file_start_write(cprm.file); |
| 762 | core_dumped = binfmt->core_dump(&cprm); |
| 763 | /* |
| 764 | * Ensures that file size is big enough to contain the current |
| 765 | * file postion. This prevents gdb from complaining about |
| 766 | * a truncated file if the last "write" to the file was |
| 767 | * dump_skip. |
| 768 | */ |
| 769 | if (cprm.to_skip) { |
| 770 | cprm.to_skip--; |
| 771 | dump_emit(&cprm, "", 1); |
| 772 | } |
| 773 | file_end_write(cprm.file); |
| 774 | free_vma_snapshot(&cprm); |
| 775 | } |
| 776 | if (ispipe && core_pipe_limit) |
| 777 | wait_for_dump_helpers(cprm.file); |
| 778 | close_fail: |
| 779 | if (cprm.file) |
| 780 | filp_close(cprm.file, NULL); |
| 781 | fail_dropcount: |
| 782 | if (ispipe) |
| 783 | atomic_dec(&core_dump_count); |
| 784 | fail_unlock: |
| 785 | kfree(argv); |
| 786 | kfree(cn.corename); |
| 787 | coredump_finish(core_dumped); |
| 788 | revert_creds(old_cred); |
| 789 | fail_creds: |
| 790 | put_cred(cred); |
| 791 | fail: |
| 792 | return; |
| 793 | } |
| 794 | |
| 795 | /* |
| 796 | * Core dumping helper functions. These are the only things you should |
| 797 | * do on a core-file: use only these functions to write out all the |
| 798 | * necessary info. |
| 799 | */ |
| 800 | static int __dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
| 801 | { |
| 802 | struct file *file = cprm->file; |
| 803 | loff_t pos = file->f_pos; |
| 804 | ssize_t n; |
| 805 | if (cprm->written + nr > cprm->limit) |
| 806 | return 0; |
| 807 | |
| 808 | |
| 809 | if (dump_interrupted()) |
| 810 | return 0; |
| 811 | n = __kernel_write(file, addr, nr, &pos); |
| 812 | if (n != nr) |
| 813 | return 0; |
| 814 | file->f_pos = pos; |
| 815 | cprm->written += n; |
| 816 | cprm->pos += n; |
| 817 | |
| 818 | return 1; |
| 819 | } |
| 820 | |
| 821 | static int __dump_skip(struct coredump_params *cprm, size_t nr) |
| 822 | { |
| 823 | static char zeroes[PAGE_SIZE]; |
| 824 | struct file *file = cprm->file; |
| 825 | if (file->f_mode & FMODE_LSEEK) { |
| 826 | if (dump_interrupted() || |
| 827 | vfs_llseek(file, nr, SEEK_CUR) < 0) |
| 828 | return 0; |
| 829 | cprm->pos += nr; |
| 830 | return 1; |
| 831 | } else { |
| 832 | while (nr > PAGE_SIZE) { |
| 833 | if (!__dump_emit(cprm, zeroes, PAGE_SIZE)) |
| 834 | return 0; |
| 835 | nr -= PAGE_SIZE; |
| 836 | } |
| 837 | return __dump_emit(cprm, zeroes, nr); |
| 838 | } |
| 839 | } |
| 840 | |
| 841 | int dump_emit(struct coredump_params *cprm, const void *addr, int nr) |
| 842 | { |
| 843 | if (cprm->to_skip) { |
| 844 | if (!__dump_skip(cprm, cprm->to_skip)) |
| 845 | return 0; |
| 846 | cprm->to_skip = 0; |
| 847 | } |
| 848 | return __dump_emit(cprm, addr, nr); |
| 849 | } |
| 850 | EXPORT_SYMBOL(dump_emit); |
| 851 | |
| 852 | void dump_skip_to(struct coredump_params *cprm, unsigned long pos) |
| 853 | { |
| 854 | cprm->to_skip = pos - cprm->pos; |
| 855 | } |
| 856 | EXPORT_SYMBOL(dump_skip_to); |
| 857 | |
| 858 | void dump_skip(struct coredump_params *cprm, size_t nr) |
| 859 | { |
| 860 | cprm->to_skip += nr; |
| 861 | } |
| 862 | EXPORT_SYMBOL(dump_skip); |
| 863 | |
| 864 | #ifdef CONFIG_ELF_CORE |
| 865 | static int dump_emit_page(struct coredump_params *cprm, struct page *page) |
| 866 | { |
| 867 | struct bio_vec bvec; |
| 868 | struct iov_iter iter; |
| 869 | struct file *file = cprm->file; |
| 870 | loff_t pos; |
| 871 | ssize_t n; |
| 872 | |
| 873 | if (cprm->to_skip) { |
| 874 | if (!__dump_skip(cprm, cprm->to_skip)) |
| 875 | return 0; |
| 876 | cprm->to_skip = 0; |
| 877 | } |
| 878 | if (cprm->written + PAGE_SIZE > cprm->limit) |
| 879 | return 0; |
| 880 | if (dump_interrupted()) |
| 881 | return 0; |
| 882 | pos = file->f_pos; |
| 883 | bvec_set_page(&bvec, page, PAGE_SIZE, 0); |
| 884 | iov_iter_bvec(&iter, ITER_SOURCE, &bvec, 1, PAGE_SIZE); |
| 885 | iov_iter_set_copy_mc(&iter); |
| 886 | n = __kernel_write_iter(cprm->file, &iter, &pos); |
| 887 | if (n != PAGE_SIZE) |
| 888 | return 0; |
| 889 | file->f_pos = pos; |
| 890 | cprm->written += PAGE_SIZE; |
| 891 | cprm->pos += PAGE_SIZE; |
| 892 | |
| 893 | return 1; |
| 894 | } |
| 895 | |
| 896 | int dump_user_range(struct coredump_params *cprm, unsigned long start, |
| 897 | unsigned long len) |
| 898 | { |
| 899 | unsigned long addr; |
| 900 | |
| 901 | for (addr = start; addr < start + len; addr += PAGE_SIZE) { |
| 902 | struct page *page; |
| 903 | |
| 904 | /* |
| 905 | * To avoid having to allocate page tables for virtual address |
| 906 | * ranges that have never been used yet, and also to make it |
| 907 | * easy to generate sparse core files, use a helper that returns |
| 908 | * NULL when encountering an empty page table entry that would |
| 909 | * otherwise have been filled with the zero page. |
| 910 | */ |
| 911 | page = get_dump_page(addr); |
| 912 | if (page) { |
| 913 | int stop = !dump_emit_page(cprm, page); |
| 914 | put_page(page); |
| 915 | if (stop) |
| 916 | return 0; |
| 917 | } else { |
| 918 | dump_skip(cprm, PAGE_SIZE); |
| 919 | } |
| 920 | } |
| 921 | return 1; |
| 922 | } |
| 923 | #endif |
| 924 | |
| 925 | int dump_align(struct coredump_params *cprm, int align) |
| 926 | { |
| 927 | unsigned mod = (cprm->pos + cprm->to_skip) & (align - 1); |
| 928 | if (align & (align - 1)) |
| 929 | return 0; |
| 930 | if (mod) |
| 931 | cprm->to_skip += align - mod; |
| 932 | return 1; |
| 933 | } |
| 934 | EXPORT_SYMBOL(dump_align); |
| 935 | |
| 936 | #ifdef CONFIG_SYSCTL |
| 937 | |
| 938 | void validate_coredump_safety(void) |
| 939 | { |
| 940 | if (suid_dumpable == SUID_DUMP_ROOT && |
| 941 | core_pattern[0] != '/' && core_pattern[0] != '|') { |
| 942 | pr_warn( |
| 943 | "Unsafe core_pattern used with fs.suid_dumpable=2.\n" |
| 944 | "Pipe handler or fully qualified core dump path required.\n" |
| 945 | "Set kernel.core_pattern before fs.suid_dumpable.\n" |
| 946 | ); |
| 947 | } |
| 948 | } |
| 949 | |
| 950 | static int proc_dostring_coredump(struct ctl_table *table, int write, |
| 951 | void *buffer, size_t *lenp, loff_t *ppos) |
| 952 | { |
| 953 | int error = proc_dostring(table, write, buffer, lenp, ppos); |
| 954 | |
| 955 | if (!error) |
| 956 | validate_coredump_safety(); |
| 957 | return error; |
| 958 | } |
| 959 | |
| 960 | static struct ctl_table coredump_sysctls[] = { |
| 961 | { |
| 962 | .procname = "core_uses_pid", |
| 963 | .data = &core_uses_pid, |
| 964 | .maxlen = sizeof(int), |
| 965 | .mode = 0644, |
| 966 | .proc_handler = proc_dointvec, |
| 967 | }, |
| 968 | { |
| 969 | .procname = "core_pattern", |
| 970 | .data = core_pattern, |
| 971 | .maxlen = CORENAME_MAX_SIZE, |
| 972 | .mode = 0644, |
| 973 | .proc_handler = proc_dostring_coredump, |
| 974 | }, |
| 975 | { |
| 976 | .procname = "core_pipe_limit", |
| 977 | .data = &core_pipe_limit, |
| 978 | .maxlen = sizeof(unsigned int), |
| 979 | .mode = 0644, |
| 980 | .proc_handler = proc_dointvec, |
| 981 | }, |
| 982 | { } |
| 983 | }; |
| 984 | |
| 985 | static int __init init_fs_coredump_sysctls(void) |
| 986 | { |
| 987 | register_sysctl_init("kernel", coredump_sysctls); |
| 988 | return 0; |
| 989 | } |
| 990 | fs_initcall(init_fs_coredump_sysctls); |
| 991 | #endif /* CONFIG_SYSCTL */ |
| 992 | |
| 993 | /* |
| 994 | * The purpose of always_dump_vma() is to make sure that special kernel mappings |
| 995 | * that are useful for post-mortem analysis are included in every core dump. |
| 996 | * In that way we ensure that the core dump is fully interpretable later |
| 997 | * without matching up the same kernel and hardware config to see what PC values |
| 998 | * meant. These special mappings include - vDSO, vsyscall, and other |
| 999 | * architecture specific mappings |
| 1000 | */ |
| 1001 | static bool always_dump_vma(struct vm_area_struct *vma) |
| 1002 | { |
| 1003 | /* Any vsyscall mappings? */ |
| 1004 | if (vma == get_gate_vma(vma->vm_mm)) |
| 1005 | return true; |
| 1006 | |
| 1007 | /* |
| 1008 | * Assume that all vmas with a .name op should always be dumped. |
| 1009 | * If this changes, a new vm_ops field can easily be added. |
| 1010 | */ |
| 1011 | if (vma->vm_ops && vma->vm_ops->name && vma->vm_ops->name(vma)) |
| 1012 | return true; |
| 1013 | |
| 1014 | /* |
| 1015 | * arch_vma_name() returns non-NULL for special architecture mappings, |
| 1016 | * such as vDSO sections. |
| 1017 | */ |
| 1018 | if (arch_vma_name(vma)) |
| 1019 | return true; |
| 1020 | |
| 1021 | return false; |
| 1022 | } |
| 1023 | |
| 1024 | #define DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER 1 |
| 1025 | |
| 1026 | /* |
| 1027 | * Decide how much of @vma's contents should be included in a core dump. |
| 1028 | */ |
| 1029 | static unsigned long vma_dump_size(struct vm_area_struct *vma, |
| 1030 | unsigned long mm_flags) |
| 1031 | { |
| 1032 | #define FILTER(type) (mm_flags & (1UL << MMF_DUMP_##type)) |
| 1033 | |
| 1034 | /* always dump the vdso and vsyscall sections */ |
| 1035 | if (always_dump_vma(vma)) |
| 1036 | goto whole; |
| 1037 | |
| 1038 | if (vma->vm_flags & VM_DONTDUMP) |
| 1039 | return 0; |
| 1040 | |
| 1041 | /* support for DAX */ |
| 1042 | if (vma_is_dax(vma)) { |
| 1043 | if ((vma->vm_flags & VM_SHARED) && FILTER(DAX_SHARED)) |
| 1044 | goto whole; |
| 1045 | if (!(vma->vm_flags & VM_SHARED) && FILTER(DAX_PRIVATE)) |
| 1046 | goto whole; |
| 1047 | return 0; |
| 1048 | } |
| 1049 | |
| 1050 | /* Hugetlb memory check */ |
| 1051 | if (is_vm_hugetlb_page(vma)) { |
| 1052 | if ((vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_SHARED)) |
| 1053 | goto whole; |
| 1054 | if (!(vma->vm_flags & VM_SHARED) && FILTER(HUGETLB_PRIVATE)) |
| 1055 | goto whole; |
| 1056 | return 0; |
| 1057 | } |
| 1058 | |
| 1059 | /* Do not dump I/O mapped devices or special mappings */ |
| 1060 | if (vma->vm_flags & VM_IO) |
| 1061 | return 0; |
| 1062 | |
| 1063 | /* By default, dump shared memory if mapped from an anonymous file. */ |
| 1064 | if (vma->vm_flags & VM_SHARED) { |
| 1065 | if (file_inode(vma->vm_file)->i_nlink == 0 ? |
| 1066 | FILTER(ANON_SHARED) : FILTER(MAPPED_SHARED)) |
| 1067 | goto whole; |
| 1068 | return 0; |
| 1069 | } |
| 1070 | |
| 1071 | /* Dump segments that have been written to. */ |
| 1072 | if ((!IS_ENABLED(CONFIG_MMU) || vma->anon_vma) && FILTER(ANON_PRIVATE)) |
| 1073 | goto whole; |
| 1074 | if (vma->vm_file == NULL) |
| 1075 | return 0; |
| 1076 | |
| 1077 | if (FILTER(MAPPED_PRIVATE)) |
| 1078 | goto whole; |
| 1079 | |
| 1080 | /* |
| 1081 | * If this is the beginning of an executable file mapping, |
| 1082 | * dump the first page to aid in determining what was mapped here. |
| 1083 | */ |
| 1084 | if (FILTER(ELF_HEADERS) && |
| 1085 | vma->vm_pgoff == 0 && (vma->vm_flags & VM_READ)) { |
| 1086 | if ((READ_ONCE(file_inode(vma->vm_file)->i_mode) & 0111) != 0) |
| 1087 | return PAGE_SIZE; |
| 1088 | |
| 1089 | /* |
| 1090 | * ELF libraries aren't always executable. |
| 1091 | * We'll want to check whether the mapping starts with the ELF |
| 1092 | * magic, but not now - we're holding the mmap lock, |
| 1093 | * so copy_from_user() doesn't work here. |
| 1094 | * Use a placeholder instead, and fix it up later in |
| 1095 | * dump_vma_snapshot(). |
| 1096 | */ |
| 1097 | return DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER; |
| 1098 | } |
| 1099 | |
| 1100 | #undef FILTER |
| 1101 | |
| 1102 | return 0; |
| 1103 | |
| 1104 | whole: |
| 1105 | return vma->vm_end - vma->vm_start; |
| 1106 | } |
| 1107 | |
| 1108 | /* |
| 1109 | * Helper function for iterating across a vma list. It ensures that the caller |
| 1110 | * will visit `gate_vma' prior to terminating the search. |
| 1111 | */ |
| 1112 | static struct vm_area_struct *coredump_next_vma(struct vma_iterator *vmi, |
| 1113 | struct vm_area_struct *vma, |
| 1114 | struct vm_area_struct *gate_vma) |
| 1115 | { |
| 1116 | if (gate_vma && (vma == gate_vma)) |
| 1117 | return NULL; |
| 1118 | |
| 1119 | vma = vma_next(vmi); |
| 1120 | if (vma) |
| 1121 | return vma; |
| 1122 | return gate_vma; |
| 1123 | } |
| 1124 | |
| 1125 | static void free_vma_snapshot(struct coredump_params *cprm) |
| 1126 | { |
| 1127 | if (cprm->vma_meta) { |
| 1128 | int i; |
| 1129 | for (i = 0; i < cprm->vma_count; i++) { |
| 1130 | struct file *file = cprm->vma_meta[i].file; |
| 1131 | if (file) |
| 1132 | fput(file); |
| 1133 | } |
| 1134 | kvfree(cprm->vma_meta); |
| 1135 | cprm->vma_meta = NULL; |
| 1136 | } |
| 1137 | } |
| 1138 | |
| 1139 | /* |
| 1140 | * Under the mmap_lock, take a snapshot of relevant information about the task's |
| 1141 | * VMAs. |
| 1142 | */ |
| 1143 | static bool dump_vma_snapshot(struct coredump_params *cprm) |
| 1144 | { |
| 1145 | struct vm_area_struct *gate_vma, *vma = NULL; |
| 1146 | struct mm_struct *mm = current->mm; |
| 1147 | VMA_ITERATOR(vmi, mm, 0); |
| 1148 | int i = 0; |
| 1149 | |
| 1150 | /* |
| 1151 | * Once the stack expansion code is fixed to not change VMA bounds |
| 1152 | * under mmap_lock in read mode, this can be changed to take the |
| 1153 | * mmap_lock in read mode. |
| 1154 | */ |
| 1155 | if (mmap_write_lock_killable(mm)) |
| 1156 | return false; |
| 1157 | |
| 1158 | cprm->vma_data_size = 0; |
| 1159 | gate_vma = get_gate_vma(mm); |
| 1160 | cprm->vma_count = mm->map_count + (gate_vma ? 1 : 0); |
| 1161 | |
| 1162 | cprm->vma_meta = kvmalloc_array(cprm->vma_count, sizeof(*cprm->vma_meta), GFP_KERNEL); |
| 1163 | if (!cprm->vma_meta) { |
| 1164 | mmap_write_unlock(mm); |
| 1165 | return false; |
| 1166 | } |
| 1167 | |
| 1168 | while ((vma = coredump_next_vma(&vmi, vma, gate_vma)) != NULL) { |
| 1169 | struct core_vma_metadata *m = cprm->vma_meta + i; |
| 1170 | |
| 1171 | m->start = vma->vm_start; |
| 1172 | m->end = vma->vm_end; |
| 1173 | m->flags = vma->vm_flags; |
| 1174 | m->dump_size = vma_dump_size(vma, cprm->mm_flags); |
| 1175 | m->pgoff = vma->vm_pgoff; |
| 1176 | m->file = vma->vm_file; |
| 1177 | if (m->file) |
| 1178 | get_file(m->file); |
| 1179 | i++; |
| 1180 | } |
| 1181 | |
| 1182 | mmap_write_unlock(mm); |
| 1183 | |
| 1184 | for (i = 0; i < cprm->vma_count; i++) { |
| 1185 | struct core_vma_metadata *m = cprm->vma_meta + i; |
| 1186 | |
| 1187 | if (m->dump_size == DUMP_SIZE_MAYBE_ELFHDR_PLACEHOLDER) { |
| 1188 | char elfmag[SELFMAG]; |
| 1189 | |
| 1190 | if (copy_from_user(elfmag, (void __user *)m->start, SELFMAG) || |
| 1191 | memcmp(elfmag, ELFMAG, SELFMAG) != 0) { |
| 1192 | m->dump_size = 0; |
| 1193 | } else { |
| 1194 | m->dump_size = PAGE_SIZE; |
| 1195 | } |
| 1196 | } |
| 1197 | |
| 1198 | cprm->vma_data_size += m->dump_size; |
| 1199 | } |
| 1200 | |
| 1201 | return true; |
| 1202 | } |