Commit | Line | Data |
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60b6c79c MD |
1 | /* |
2 | * Copyright (C) 2011 - David Goulet <david.goulet@polymtl.ca> | |
3 | * Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
4 | * | |
d14d33bf AM |
5 | * This program is free software; you can redistribute it and/or modify |
6 | * it under the terms of the GNU General Public License, version 2 only, | |
7 | * as published by the Free Software Foundation. | |
60b6c79c MD |
8 | * |
9 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
d14d33bf | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for |
60b6c79c MD |
12 | * more details. |
13 | * | |
d14d33bf AM |
14 | * You should have received a copy of the GNU General Public License along |
15 | * with this program; if not, write to the Free Software Foundation, Inc., | |
16 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
60b6c79c MD |
17 | */ |
18 | ||
6c1c0768 | 19 | #define _LGPL_SOURCE |
60b6c79c MD |
20 | #include <errno.h> |
21 | #include <limits.h> | |
22 | #include <stdio.h> | |
23 | #include <stdlib.h> | |
24 | #include <string.h> | |
25 | #include <sys/wait.h> | |
26 | #include <sys/types.h> | |
27 | #include <sys/stat.h> | |
28 | #include <unistd.h> | |
29 | #include <fcntl.h> | |
c2b75c49 | 30 | #include <sched.h> |
0452bf08 | 31 | #include <signal.h> |
749b7a0c | 32 | #include <assert.h> |
e1055edb | 33 | #include <signal.h> |
60b6c79c | 34 | |
90e535ef | 35 | #include <common/common.h> |
3fd15a74 | 36 | #include <common/utils.h> |
e8fa9fb0 | 37 | #include <common/compat/getenv.h> |
e1055edb | 38 | #include <common/compat/prctl.h> |
2038dd6c JG |
39 | #include <common/unix.h> |
40 | #include <common/defaults.h> | |
241e0a5a FD |
41 | #include <common/lttng-elf.h> |
42 | ||
43 | #include <lttng/constant.h> | |
60b6c79c | 44 | |
0857097f DG |
45 | #include "runas.h" |
46 | ||
7567352f | 47 | struct run_as_data; |
fe9f7760 FD |
48 | struct run_as_ret; |
49 | typedef int (*run_as_fct)(struct run_as_data *data, struct run_as_ret *ret_value); | |
c2b75c49 | 50 | |
e11d277b | 51 | struct run_as_mkdir_data { |
7567352f | 52 | char path[PATH_MAX]; |
60b6c79c MD |
53 | mode_t mode; |
54 | }; | |
55 | ||
e11d277b | 56 | struct run_as_open_data { |
7567352f | 57 | char path[PATH_MAX]; |
60b6c79c MD |
58 | int flags; |
59 | mode_t mode; | |
60 | }; | |
61 | ||
4628484a | 62 | struct run_as_unlink_data { |
7567352f | 63 | char path[PATH_MAX]; |
4628484a MD |
64 | }; |
65 | ||
7567352f MD |
66 | struct run_as_rmdir_recursive_data { |
67 | char path[PATH_MAX]; | |
68 | }; | |
69 | ||
241e0a5a FD |
70 | struct run_as_extract_elf_symbol_offset_data { |
71 | char function[LTTNG_SYMBOL_NAME_LEN]; | |
72 | }; | |
73 | ||
fe9f7760 FD |
74 | struct run_as_mkdir_ret { |
75 | int ret; | |
76 | }; | |
77 | ||
78 | struct run_as_open_ret { | |
79 | int ret; | |
80 | }; | |
81 | ||
82 | struct run_as_unlink_ret { | |
83 | int ret; | |
84 | }; | |
85 | ||
86 | struct run_as_rmdir_recursive_ret { | |
87 | int ret; | |
88 | }; | |
89 | ||
241e0a5a FD |
90 | struct run_as_extract_elf_symbol_offset_ret { |
91 | uint64_t offset; | |
92 | }; | |
93 | ||
7567352f MD |
94 | enum run_as_cmd { |
95 | RUN_AS_MKDIR, | |
96 | RUN_AS_OPEN, | |
97 | RUN_AS_UNLINK, | |
98 | RUN_AS_RMDIR_RECURSIVE, | |
99 | RUN_AS_MKDIR_RECURSIVE, | |
241e0a5a | 100 | RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, |
7567352f MD |
101 | }; |
102 | ||
103 | struct run_as_data { | |
104 | enum run_as_cmd cmd; | |
fe9f7760 | 105 | int fd; |
7567352f MD |
106 | union { |
107 | struct run_as_mkdir_data mkdir; | |
108 | struct run_as_open_data open; | |
109 | struct run_as_unlink_data unlink; | |
110 | struct run_as_rmdir_recursive_data rmdir_recursive; | |
241e0a5a | 111 | struct run_as_extract_elf_symbol_offset_data extract_elf_symbol_offset; |
7567352f MD |
112 | } u; |
113 | uid_t uid; | |
114 | gid_t gid; | |
4628484a MD |
115 | }; |
116 | ||
fe9f7760 FD |
117 | /* |
118 | * The run_as_ret structure holds the returned value and status of the command. | |
119 | * | |
120 | * The `u` union field holds the return value of the command; in most cases it | |
121 | * represents the success or the failure of the command. In more complex | |
122 | * commands, it holds a computed value. | |
123 | * | |
124 | * The _errno field is the errno recorded after the execution of the command. | |
125 | * | |
126 | * The _error fields is used the signify that return status of the command. For | |
127 | * simple commands returning `int` the _error field will be the same as the | |
128 | * ret_int field. In complex commands, it signify the success or failure of the | |
129 | * command. | |
130 | * | |
131 | */ | |
df5b86c8 | 132 | struct run_as_ret { |
fe9f7760 FD |
133 | int fd; |
134 | union { | |
135 | struct run_as_mkdir_ret mkdir; | |
136 | struct run_as_open_ret open; | |
137 | struct run_as_unlink_ret unlink; | |
138 | struct run_as_rmdir_recursive_ret rmdir_recursive; | |
241e0a5a | 139 | struct run_as_extract_elf_symbol_offset_ret extract_elf_symbol_offset; |
fe9f7760 | 140 | } u; |
df5b86c8 | 141 | int _errno; |
fe9f7760 | 142 | bool _error; |
df5b86c8 MD |
143 | }; |
144 | ||
7567352f MD |
145 | struct run_as_worker { |
146 | pid_t pid; /* Worker PID. */ | |
147 | int sockpair[2]; | |
148 | char *procname; | |
149 | }; | |
150 | ||
151 | /* Single global worker per process (for now). */ | |
152 | static struct run_as_worker *global_worker; | |
153 | /* Lock protecting the worker. */ | |
154 | static pthread_mutex_t worker_lock = PTHREAD_MUTEX_INITIALIZER; | |
155 | ||
8f0044bf MD |
156 | #ifdef VALGRIND |
157 | static | |
158 | int use_clone(void) | |
159 | { | |
160 | return 0; | |
161 | } | |
162 | #else | |
163 | static | |
164 | int use_clone(void) | |
165 | { | |
e8fa9fb0 | 166 | return !lttng_secure_getenv("LTTNG_DEBUG_NOCLONE"); |
8f0044bf MD |
167 | } |
168 | #endif | |
169 | ||
d77dded2 JG |
170 | LTTNG_HIDDEN |
171 | int _utils_mkdir_recursive_unsafe(const char *path, mode_t mode); | |
172 | ||
60b6c79c MD |
173 | /* |
174 | * Create recursively directory using the FULL path. | |
175 | */ | |
176 | static | |
fe9f7760 | 177 | int _mkdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value) |
60b6c79c | 178 | { |
60b6c79c | 179 | const char *path; |
60b6c79c | 180 | mode_t mode; |
60b6c79c | 181 | |
7567352f MD |
182 | path = data->u.mkdir.path; |
183 | mode = data->u.mkdir.mode; | |
60b6c79c | 184 | |
d77dded2 | 185 | /* Safe to call as we have transitioned to the requested uid/gid. */ |
fe9f7760 FD |
186 | ret_value->u.mkdir.ret = _utils_mkdir_recursive_unsafe(path, mode); |
187 | ret_value->_errno = errno; | |
188 | ret_value->_error = (ret_value->u.mkdir.ret) ? true : false; | |
189 | return ret_value->u.mkdir.ret; | |
60b6c79c MD |
190 | } |
191 | ||
192 | static | |
fe9f7760 | 193 | int _mkdir(struct run_as_data *data, struct run_as_ret *ret_value) |
60b6c79c | 194 | { |
fe9f7760 FD |
195 | ret_value->u.mkdir.ret = mkdir(data->u.mkdir.path, data->u.mkdir.mode); |
196 | ret_value->_errno = errno; | |
197 | ret_value->_error = (ret_value->u.mkdir.ret) ? true : false; | |
198 | return ret_value->u.mkdir.ret; | |
7567352f | 199 | } |
7ce36756 | 200 | |
7567352f | 201 | static |
fe9f7760 | 202 | int _open(struct run_as_data *data, struct run_as_ret *ret_value) |
7567352f | 203 | { |
fe9f7760 FD |
204 | ret_value->u.open.ret = open(data->u.open.path, data->u.open.flags, data->u.open.mode); |
205 | ret_value->fd = ret_value->u.open.ret; | |
206 | ret_value->_errno = errno; | |
207 | ret_value->_error = (ret_value->u.open.ret) ? true : false; | |
208 | return ret_value->u.open.ret; | |
7567352f MD |
209 | } |
210 | ||
211 | static | |
fe9f7760 | 212 | int _unlink(struct run_as_data *data, struct run_as_ret *ret_value) |
7567352f | 213 | { |
fe9f7760 FD |
214 | ret_value->u.unlink.ret = unlink(data->u.unlink.path); |
215 | ret_value->_errno = errno; | |
216 | ret_value->_error = (ret_value->u.unlink.ret) ? true : false; | |
217 | return ret_value->u.unlink.ret; | |
60b6c79c MD |
218 | } |
219 | ||
220 | static | |
fe9f7760 | 221 | int _rmdir_recursive(struct run_as_data *data, struct run_as_ret *ret_value) |
60b6c79c | 222 | { |
fe9f7760 FD |
223 | ret_value->u.rmdir_recursive.ret = utils_recursive_rmdir(data->u.rmdir_recursive.path); |
224 | ret_value->_errno = errno; | |
225 | ret_value->_error = (ret_value->u.rmdir_recursive.ret) ? true : false; | |
226 | return ret_value->u.rmdir_recursive.ret; | |
7567352f | 227 | } |
df5b86c8 | 228 | |
241e0a5a FD |
229 | static |
230 | int _extract_elf_symbol_offset(struct run_as_data *data, | |
231 | struct run_as_ret *ret_value) | |
232 | { | |
233 | int ret = 0; | |
234 | ret_value->_error = false; | |
235 | ||
236 | ret = lttng_elf_get_symbol_offset(data->fd, | |
237 | data->u.extract_elf_symbol_offset.function, | |
238 | &ret_value->u.extract_elf_symbol_offset.offset); | |
239 | if (ret) { | |
240 | DBG("Failed to extract ELF function offset"); | |
241 | ret_value->_error = true; | |
242 | } | |
243 | ||
244 | return ret; | |
245 | } | |
246 | ||
247 | ||
7567352f MD |
248 | static |
249 | run_as_fct run_as_enum_to_fct(enum run_as_cmd cmd) | |
250 | { | |
251 | switch (cmd) { | |
252 | case RUN_AS_MKDIR: | |
253 | return _mkdir; | |
254 | case RUN_AS_OPEN: | |
255 | return _open; | |
256 | case RUN_AS_UNLINK: | |
257 | return _unlink; | |
258 | case RUN_AS_RMDIR_RECURSIVE: | |
259 | return _rmdir_recursive; | |
260 | case RUN_AS_MKDIR_RECURSIVE: | |
261 | return _mkdir_recursive; | |
241e0a5a FD |
262 | case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET: |
263 | return _extract_elf_symbol_offset; | |
7567352f | 264 | default: |
62a7b8ed | 265 | ERR("Unknown command %d", (int) cmd); |
7567352f MD |
266 | return NULL; |
267 | } | |
60b6c79c MD |
268 | } |
269 | ||
4628484a | 270 | static |
fe9f7760 | 271 | int do_send_fd(int sock, int fd) |
4628484a | 272 | { |
7567352f | 273 | ssize_t len; |
4628484a | 274 | |
7567352f | 275 | if (fd < 0) { |
fe9f7760 | 276 | ERR("Invalid file description"); |
7567352f MD |
277 | return 0; |
278 | } | |
fe9f7760 FD |
279 | |
280 | len = lttcomm_send_fds_unix_sock(sock, &fd, 1); | |
7567352f MD |
281 | if (len < 0) { |
282 | PERROR("lttcomm_send_fds_unix_sock"); | |
283 | return -1; | |
284 | } | |
7567352f | 285 | return 0; |
4628484a MD |
286 | } |
287 | ||
288 | static | |
fe9f7760 | 289 | int do_recv_fd(int sock, int *fd) |
4628484a | 290 | { |
7567352f | 291 | ssize_t len; |
4628484a | 292 | |
7567352f | 293 | if (*fd < 0) { |
fe9f7760 | 294 | ERR("Invalid file description"); |
7567352f MD |
295 | return 0; |
296 | } | |
fe9f7760 FD |
297 | |
298 | len = lttcomm_recv_fds_unix_sock(sock, fd, 1); | |
299 | ||
da9ee832 JG |
300 | if (!len) { |
301 | return -1; | |
302 | } else if (len < 0) { | |
7567352f MD |
303 | PERROR("lttcomm_recv_fds_unix_sock"); |
304 | return -1; | |
305 | } | |
306 | return 0; | |
4628484a MD |
307 | } |
308 | ||
fe9f7760 FD |
309 | static |
310 | int send_fd_to_worker(struct run_as_worker *worker, enum run_as_cmd cmd, int fd) | |
311 | { | |
312 | int ret = 0; | |
313 | ||
314 | switch (cmd) { | |
241e0a5a FD |
315 | case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET: |
316 | break; | |
fe9f7760 FD |
317 | default: |
318 | return 0; | |
319 | } | |
320 | ||
321 | ret = do_send_fd(worker->sockpair[0], fd); | |
322 | if (ret < 0) { | |
323 | PERROR("do_send_fd"); | |
324 | ret = -1; | |
325 | } | |
326 | ||
327 | return ret; | |
328 | } | |
329 | ||
330 | static | |
331 | int send_fd_to_master(struct run_as_worker *worker, enum run_as_cmd cmd, int fd) | |
332 | { | |
333 | int ret = 0, ret_close = 0; | |
334 | ||
335 | switch (cmd) { | |
336 | case RUN_AS_OPEN: | |
337 | break; | |
338 | default: | |
339 | return 0; | |
340 | } | |
341 | ||
342 | ret = do_send_fd(worker->sockpair[1], fd); | |
343 | if (ret < 0) { | |
344 | PERROR("do_send_fd error"); | |
345 | ret = -1; | |
346 | } | |
347 | ||
348 | ret_close = close(fd); | |
349 | if (ret_close < 0) { | |
350 | PERROR("close"); | |
351 | } | |
352 | ||
353 | return ret; | |
354 | } | |
355 | ||
356 | static | |
357 | int recv_fd_from_worker(struct run_as_worker *worker, enum run_as_cmd cmd, int *fd) | |
358 | { | |
359 | int ret = 0; | |
360 | ||
361 | switch (cmd) { | |
362 | case RUN_AS_OPEN: | |
363 | break; | |
364 | default: | |
365 | return 0; | |
366 | } | |
367 | ||
368 | ret = do_recv_fd(worker->sockpair[0], fd); | |
369 | if (ret < 0) { | |
370 | PERROR("do_recv_fd error"); | |
371 | ret = -1; | |
372 | } | |
373 | ||
374 | return ret; | |
375 | } | |
376 | ||
377 | static | |
378 | int recv_fd_from_master(struct run_as_worker *worker, enum run_as_cmd cmd, int *fd) | |
379 | { | |
380 | int ret = 0; | |
381 | ||
382 | switch (cmd) { | |
241e0a5a FD |
383 | case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET: |
384 | break; | |
fe9f7760 FD |
385 | default: |
386 | return 0; | |
387 | } | |
388 | ||
389 | ret = do_recv_fd(worker->sockpair[1], fd); | |
390 | if (ret < 0) { | |
391 | PERROR("do_recv_fd error"); | |
392 | ret = -1; | |
393 | } | |
394 | ||
395 | return ret; | |
396 | } | |
397 | ||
398 | static | |
399 | int cleanup_received_fd(enum run_as_cmd cmd, int fd) | |
400 | { | |
401 | int ret = 0; | |
402 | ||
403 | switch (cmd) { | |
241e0a5a FD |
404 | case RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET: |
405 | break; | |
fe9f7760 FD |
406 | default: |
407 | return 0; | |
408 | } | |
409 | ||
410 | ret = close(fd); | |
411 | if (ret < 0) { | |
412 | PERROR("close error"); | |
413 | ret = -1; | |
414 | } | |
415 | ||
416 | return ret; | |
417 | } | |
7567352f MD |
418 | /* |
419 | * Return < 0 on error, 0 if OK, 1 on hangup. | |
420 | */ | |
c2b75c49 | 421 | static |
7567352f | 422 | int handle_one_cmd(struct run_as_worker *worker) |
c2b75c49 | 423 | { |
7567352f MD |
424 | int ret = 0; |
425 | struct run_as_data data; | |
426 | ssize_t readlen, writelen; | |
df5b86c8 | 427 | struct run_as_ret sendret; |
7567352f MD |
428 | run_as_fct cmd; |
429 | uid_t prev_euid; | |
430 | ||
fe9f7760 FD |
431 | /* |
432 | * Stage 1: Receive run_as_data struct from the master. | |
433 | * The structure contains the command type and all the parameters needed for | |
434 | * its execution | |
435 | */ | |
7567352f MD |
436 | readlen = lttcomm_recv_unix_sock(worker->sockpair[1], &data, |
437 | sizeof(data)); | |
438 | if (readlen == 0) { | |
439 | /* hang up */ | |
440 | ret = 1; | |
441 | goto end; | |
442 | } | |
443 | if (readlen < sizeof(data)) { | |
444 | PERROR("lttcomm_recv_unix_sock error"); | |
445 | ret = -1; | |
446 | goto end; | |
447 | } | |
c2b75c49 | 448 | |
7567352f MD |
449 | cmd = run_as_enum_to_fct(data.cmd); |
450 | if (!cmd) { | |
451 | ret = -1; | |
452 | goto end; | |
453 | } | |
454 | ||
fe9f7760 FD |
455 | /* |
456 | * Stage 2: Receive file descriptor from master. | |
457 | * Some commands need a file descriptor as input so if it's needed we | |
458 | * receive the fd using the Unix socket. | |
459 | */ | |
460 | ret = recv_fd_from_master(worker, data.cmd, &data.fd); | |
461 | if (ret < 0) { | |
462 | PERROR("recv_fd_from_master error"); | |
463 | ret = -1; | |
464 | goto end; | |
465 | } | |
466 | ||
7567352f MD |
467 | prev_euid = getuid(); |
468 | if (data.gid != getegid()) { | |
469 | ret = setegid(data.gid); | |
1576d582 | 470 | if (ret < 0) { |
4c462e79 | 471 | PERROR("setegid"); |
6d73c4ef | 472 | goto write_return; |
1576d582 | 473 | } |
c2b75c49 | 474 | } |
7567352f MD |
475 | if (data.uid != prev_euid) { |
476 | ret = seteuid(data.uid); | |
1576d582 | 477 | if (ret < 0) { |
4c462e79 | 478 | PERROR("seteuid"); |
6d73c4ef | 479 | goto write_return; |
1576d582 | 480 | } |
c2b75c49 | 481 | } |
fe9f7760 | 482 | |
c2b75c49 MD |
483 | /* |
484 | * Also set umask to 0 for mkdir executable bit. | |
485 | */ | |
486 | umask(0); | |
fe9f7760 FD |
487 | |
488 | /* | |
489 | * Stage 3: Execute the command | |
490 | */ | |
491 | ret = (*cmd)(&data, &sendret); | |
492 | if (ret < 0) { | |
493 | DBG("Execution of command returned an error"); | |
494 | } | |
6d73c4ef MD |
495 | |
496 | write_return: | |
fe9f7760 FD |
497 | ret = cleanup_received_fd(data.cmd, data.fd); |
498 | if (ret < 0) { | |
499 | ERR("Error cleaning up FD"); | |
500 | goto end; | |
501 | } | |
502 | ||
503 | /* | |
504 | * Stage 4: Send run_as_ret structure to the master. | |
505 | * This structure contain the return value of the command and the errno. | |
506 | */ | |
7567352f MD |
507 | writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret, |
508 | sizeof(sendret)); | |
6cd525e8 | 509 | if (writelen < sizeof(sendret)) { |
7567352f MD |
510 | PERROR("lttcomm_send_unix_sock error"); |
511 | ret = -1; | |
512 | goto end; | |
513 | } | |
fe9f7760 FD |
514 | |
515 | /* | |
516 | * Stage 5: Send file descriptor to the master | |
517 | * Some commands return a file descriptor so if it's needed we pass it back | |
518 | * to the master using the Unix socket. | |
519 | */ | |
520 | ret = send_fd_to_master(worker, data.cmd, sendret.fd); | |
521 | if (ret < 0) { | |
522 | DBG("Sending FD to master returned an error"); | |
7567352f MD |
523 | goto end; |
524 | } | |
fe9f7760 | 525 | |
7567352f MD |
526 | if (seteuid(prev_euid) < 0) { |
527 | PERROR("seteuid"); | |
528 | ret = -1; | |
529 | goto end; | |
530 | } | |
531 | ret = 0; | |
532 | end: | |
533 | return ret; | |
534 | } | |
535 | ||
536 | static | |
537 | int run_as_worker(struct run_as_worker *worker) | |
538 | { | |
539 | int ret; | |
540 | ssize_t writelen; | |
541 | struct run_as_ret sendret; | |
542 | size_t proc_orig_len; | |
543 | ||
544 | /* | |
545 | * Initialize worker. Set a different process cmdline. | |
546 | */ | |
547 | proc_orig_len = strlen(worker->procname); | |
548 | memset(worker->procname, 0, proc_orig_len); | |
549 | strncpy(worker->procname, DEFAULT_RUN_AS_WORKER_NAME, proc_orig_len); | |
550 | ||
e1055edb JG |
551 | ret = lttng_prctl(PR_SET_NAME, |
552 | (unsigned long) DEFAULT_RUN_AS_WORKER_NAME, 0, 0, 0); | |
553 | if (ret && ret != -ENOSYS) { | |
b8090274 JG |
554 | /* Don't fail as this is not essential. */ |
555 | PERROR("prctl PR_SET_NAME"); | |
6cd525e8 | 556 | } |
7567352f | 557 | |
fe9f7760 FD |
558 | memset(&sendret, 0, sizeof(sendret)); |
559 | ||
7567352f MD |
560 | writelen = lttcomm_send_unix_sock(worker->sockpair[1], &sendret, |
561 | sizeof(sendret)); | |
562 | if (writelen < sizeof(sendret)) { | |
563 | PERROR("lttcomm_send_unix_sock error"); | |
564 | ret = EXIT_FAILURE; | |
565 | goto end; | |
566 | } | |
567 | ||
568 | for (;;) { | |
569 | ret = handle_one_cmd(worker); | |
570 | if (ret < 0) { | |
571 | ret = EXIT_FAILURE; | |
572 | goto end; | |
573 | } else if (ret > 0) { | |
574 | break; | |
575 | } else { | |
576 | continue; /* Next command. */ | |
577 | } | |
578 | } | |
579 | ret = EXIT_SUCCESS; | |
580 | end: | |
581 | return ret; | |
c2b75c49 MD |
582 | } |
583 | ||
60b6c79c | 584 | static |
7567352f MD |
585 | int run_as_cmd(struct run_as_worker *worker, |
586 | enum run_as_cmd cmd, | |
587 | struct run_as_data *data, | |
fe9f7760 | 588 | struct run_as_ret *ret_value, |
7567352f | 589 | uid_t uid, gid_t gid) |
60b6c79c | 590 | { |
fe9f7760 | 591 | int ret = 0; |
7567352f | 592 | ssize_t readlen, writelen; |
60b6c79c MD |
593 | |
594 | /* | |
595 | * If we are non-root, we can only deal with our own uid. | |
596 | */ | |
597 | if (geteuid() != 0) { | |
598 | if (uid != geteuid()) { | |
fe9f7760 FD |
599 | ret = -1; |
600 | ret_value->_errno = EPERM; | |
60b6c79c | 601 | ERR("Client (%d)/Server (%d) UID mismatch (and sessiond is not root)", |
08797918 | 602 | (int) uid, (int) geteuid()); |
df5b86c8 | 603 | goto end; |
60b6c79c | 604 | } |
60b6c79c MD |
605 | } |
606 | ||
7567352f MD |
607 | data->cmd = cmd; |
608 | data->uid = uid; | |
609 | data->gid = gid; | |
610 | ||
fe9f7760 FD |
611 | /* |
612 | * Stage 1: Send the run_as_data struct to the worker process | |
613 | */ | |
7567352f MD |
614 | writelen = lttcomm_send_unix_sock(worker->sockpair[0], data, |
615 | sizeof(*data)); | |
616 | if (writelen < sizeof(*data)) { | |
617 | PERROR("Error writing message to run_as"); | |
fe9f7760 FD |
618 | ret = -1; |
619 | ret_value->_errno = EIO; | |
60b6c79c | 620 | goto end; |
c2b75c49 | 621 | } |
7567352f | 622 | |
fe9f7760 FD |
623 | /* |
624 | * Stage 2: Send file descriptor to the worker process if needed | |
625 | */ | |
626 | ret = send_fd_to_worker(worker, data->cmd, data->fd); | |
627 | if (ret) { | |
628 | PERROR("do_send_fd error"); | |
629 | ret = -1; | |
630 | ret_value->_errno = EIO; | |
631 | goto end; | |
632 | } | |
633 | ||
634 | /* | |
635 | * Stage 3: Wait for the execution of the command | |
636 | */ | |
637 | ||
638 | /* | |
639 | * Stage 4: Receive the run_as_ret struct containing the return value and | |
640 | * errno | |
641 | */ | |
642 | readlen = lttcomm_recv_unix_sock(worker->sockpair[0], ret_value, | |
643 | sizeof(*ret_value)); | |
da9ee832 JG |
644 | if (!readlen) { |
645 | ERR("Run-as worker has hung-up during run_as_cmd"); | |
fe9f7760 FD |
646 | ret = -1; |
647 | ret_value->_errno = EIO; | |
da9ee832 | 648 | goto end; |
fe9f7760 | 649 | } else if (readlen < sizeof(*ret_value)) { |
7567352f | 650 | PERROR("Error reading response from run_as"); |
fe9f7760 FD |
651 | ret = -1; |
652 | ret_value->_errno = errno; | |
6cd525e8 | 653 | } |
fe9f7760 FD |
654 | |
655 | /* | |
656 | * Stage 5: Receive file descriptor if needed | |
657 | */ | |
658 | ret = recv_fd_from_worker(worker, data->cmd, &ret_value->fd); | |
659 | if (ret < 0) { | |
660 | ERR("Error receiving fd"); | |
661 | ret = -1; | |
662 | ret_value->_errno = EIO; | |
4c462e79 | 663 | } |
7567352f | 664 | |
60b6c79c | 665 | end: |
fe9f7760 | 666 | return ret; |
60b6c79c MD |
667 | } |
668 | ||
2d85a600 | 669 | /* |
7567352f | 670 | * This is for debugging ONLY and should not be considered secure. |
2d85a600 MD |
671 | */ |
672 | static | |
fe9f7760 FD |
673 | int run_as_noworker(enum run_as_cmd cmd, |
674 | struct run_as_data *data, struct run_as_ret *ret_value, | |
675 | uid_t uid, gid_t gid) | |
2d85a600 | 676 | { |
df5b86c8 | 677 | int ret, saved_errno; |
5b73926f | 678 | mode_t old_mask; |
7567352f | 679 | run_as_fct fct; |
5b73926f | 680 | |
7567352f MD |
681 | fct = run_as_enum_to_fct(cmd); |
682 | if (!fct) { | |
683 | errno = -ENOSYS; | |
684 | ret = -1; | |
685 | goto end; | |
686 | } | |
5b73926f | 687 | old_mask = umask(0); |
fe9f7760 FD |
688 | ret = fct(data, ret_value); |
689 | saved_errno = ret_value->_errno; | |
5b73926f | 690 | umask(old_mask); |
df5b86c8 | 691 | errno = saved_errno; |
7567352f | 692 | end: |
5b73926f | 693 | return ret; |
2d85a600 MD |
694 | } |
695 | ||
696 | static | |
fe9f7760 | 697 | int run_as_restart_worker(struct run_as_worker *worker) |
2d85a600 | 698 | { |
fe9f7760 FD |
699 | int ret = 0; |
700 | char *procname = NULL; | |
701 | ||
702 | procname = worker->procname; | |
703 | ||
704 | /* Close socket to run_as worker process and clean up the zombie process */ | |
705 | run_as_destroy_worker(); | |
706 | ||
707 | /* Create a new run_as worker process*/ | |
708 | ret = run_as_create_worker(procname); | |
709 | if (ret < 0 ) { | |
710 | ERR("Restarting the worker process failed"); | |
711 | ret = -1; | |
712 | goto err; | |
713 | } | |
714 | err: | |
715 | return ret; | |
716 | } | |
717 | ||
718 | static | |
719 | int run_as(enum run_as_cmd cmd, struct run_as_data *data, | |
720 | struct run_as_ret *ret_value, uid_t uid, gid_t gid) | |
721 | { | |
722 | int ret, saved_errno; | |
7567352f | 723 | |
749b7a0c | 724 | if (use_clone()) { |
7567352f | 725 | DBG("Using run_as worker"); |
749b7a0c JG |
726 | pthread_mutex_lock(&worker_lock); |
727 | assert(global_worker); | |
749b7a0c | 728 | |
fe9f7760 FD |
729 | ret = run_as_cmd(global_worker, cmd, data, ret_value, uid, gid); |
730 | saved_errno = ret_value->_errno; | |
731 | ||
732 | pthread_mutex_unlock(&worker_lock); | |
733 | /* | |
734 | * If the worker thread crashed the errno is set to EIO. we log | |
735 | * the error and start a new worker process. | |
736 | */ | |
737 | if (ret == -1 && saved_errno == EIO) { | |
738 | DBG("Socket closed unexpectedly... " | |
739 | "Restarting the worker process"); | |
740 | ret = run_as_restart_worker(global_worker); | |
741 | ||
742 | if (ret == -1) { | |
743 | ERR("Failed to restart worker process."); | |
744 | goto err; | |
745 | } | |
746 | } | |
2d85a600 | 747 | } else { |
7567352f | 748 | DBG("Using run_as without worker"); |
fe9f7760 | 749 | ret = run_as_noworker(cmd, data, ret_value, uid, gid); |
2d85a600 | 750 | } |
fe9f7760 | 751 | err: |
7567352f | 752 | return ret; |
2d85a600 MD |
753 | } |
754 | ||
90e535ef | 755 | LTTNG_HIDDEN |
e11d277b | 756 | int run_as_mkdir_recursive(const char *path, mode_t mode, uid_t uid, gid_t gid) |
60b6c79c | 757 | { |
7567352f | 758 | struct run_as_data data; |
fe9f7760 | 759 | struct run_as_ret ret; |
60b6c79c | 760 | |
8446e5eb | 761 | memset(&data, 0, sizeof(data)); |
fe9f7760 | 762 | memset(&ret, 0, sizeof(ret)); |
60b6c79c | 763 | DBG3("mkdir() recursive %s with mode %d for uid %d and gid %d", |
08797918 | 764 | path, (int) mode, (int) uid, (int) gid); |
7567352f MD |
765 | strncpy(data.u.mkdir.path, path, PATH_MAX - 1); |
766 | data.u.mkdir.path[PATH_MAX - 1] = '\0'; | |
767 | data.u.mkdir.mode = mode; | |
fe9f7760 FD |
768 | |
769 | run_as(RUN_AS_MKDIR_RECURSIVE, &data, &ret, uid, gid); | |
770 | errno = ret._errno; | |
771 | return ret.u.mkdir.ret; | |
60b6c79c MD |
772 | } |
773 | ||
90e535ef | 774 | LTTNG_HIDDEN |
e11d277b | 775 | int run_as_mkdir(const char *path, mode_t mode, uid_t uid, gid_t gid) |
60b6c79c | 776 | { |
7567352f | 777 | struct run_as_data data; |
fe9f7760 | 778 | struct run_as_ret ret; |
60b6c79c | 779 | |
8446e5eb | 780 | memset(&data, 0, sizeof(data)); |
fe9f7760 FD |
781 | memset(&ret, 0, sizeof(ret)); |
782 | ||
60b6c79c | 783 | DBG3("mkdir() %s with mode %d for uid %d and gid %d", |
08797918 | 784 | path, (int) mode, (int) uid, (int) gid); |
7567352f MD |
785 | strncpy(data.u.mkdir.path, path, PATH_MAX - 1); |
786 | data.u.mkdir.path[PATH_MAX - 1] = '\0'; | |
787 | data.u.mkdir.mode = mode; | |
fe9f7760 FD |
788 | run_as(RUN_AS_MKDIR, &data, &ret, uid, gid); |
789 | errno = ret._errno; | |
790 | return ret.u.mkdir.ret; | |
60b6c79c MD |
791 | } |
792 | ||
90e535ef | 793 | LTTNG_HIDDEN |
e11d277b | 794 | int run_as_open(const char *path, int flags, mode_t mode, uid_t uid, gid_t gid) |
60b6c79c | 795 | { |
7567352f | 796 | struct run_as_data data; |
fe9f7760 | 797 | struct run_as_ret ret; |
c2b75c49 | 798 | |
8446e5eb | 799 | memset(&data, 0, sizeof(data)); |
fe9f7760 FD |
800 | memset(&ret, 0, sizeof(ret)); |
801 | ||
47fb7563 | 802 | DBG3("open() %s with flags %X mode %d for uid %d and gid %d", |
08797918 | 803 | path, flags, (int) mode, (int) uid, (int) gid); |
7567352f MD |
804 | strncpy(data.u.open.path, path, PATH_MAX - 1); |
805 | data.u.open.path[PATH_MAX - 1] = '\0'; | |
806 | data.u.open.flags = flags; | |
807 | data.u.open.mode = mode; | |
fe9f7760 FD |
808 | run_as(RUN_AS_OPEN, &data, &ret, uid, gid); |
809 | errno = ret._errno; | |
810 | ret.u.open.ret = ret.fd; | |
811 | return ret.u.open.ret; | |
60b6c79c | 812 | } |
4628484a MD |
813 | |
814 | LTTNG_HIDDEN | |
815 | int run_as_unlink(const char *path, uid_t uid, gid_t gid) | |
816 | { | |
7567352f | 817 | struct run_as_data data; |
fe9f7760 | 818 | struct run_as_ret ret; |
4628484a | 819 | |
8446e5eb | 820 | memset(&data, 0, sizeof(data)); |
fe9f7760 FD |
821 | memset(&ret, 0, sizeof(ret)); |
822 | ||
4628484a | 823 | DBG3("unlink() %s with for uid %d and gid %d", |
08797918 | 824 | path, (int) uid, (int) gid); |
7567352f MD |
825 | strncpy(data.u.unlink.path, path, PATH_MAX - 1); |
826 | data.u.unlink.path[PATH_MAX - 1] = '\0'; | |
fe9f7760 FD |
827 | run_as(RUN_AS_UNLINK, &data, &ret, uid, gid); |
828 | errno = ret._errno; | |
829 | return ret.u.unlink.ret; | |
4628484a MD |
830 | } |
831 | ||
832 | LTTNG_HIDDEN | |
7567352f | 833 | int run_as_rmdir_recursive(const char *path, uid_t uid, gid_t gid) |
4628484a | 834 | { |
7567352f | 835 | struct run_as_data data; |
fe9f7760 FD |
836 | struct run_as_ret ret; |
837 | ||
838 | memset(&data, 0, sizeof(data)); | |
839 | memset(&ret, 0, sizeof(ret)); | |
4628484a | 840 | |
7567352f | 841 | DBG3("rmdir_recursive() %s with for uid %d and gid %d", |
08797918 | 842 | path, (int) uid, (int) gid); |
7567352f MD |
843 | strncpy(data.u.rmdir_recursive.path, path, PATH_MAX - 1); |
844 | data.u.rmdir_recursive.path[PATH_MAX - 1] = '\0'; | |
fe9f7760 FD |
845 | run_as(RUN_AS_RMDIR_RECURSIVE, &data, &ret, uid, gid); |
846 | errno = ret._errno; | |
847 | return ret.u.rmdir_recursive.ret; | |
7567352f MD |
848 | } |
849 | ||
241e0a5a FD |
850 | LTTNG_HIDDEN |
851 | int run_as_extract_elf_symbol_offset(int fd, const char* function, | |
852 | uid_t uid, gid_t gid, uint64_t *offset) | |
853 | { | |
854 | struct run_as_data data; | |
855 | struct run_as_ret ret; | |
856 | ||
857 | DBG3("extract_elf_symbol_offset() on fd=%d and function=%s " | |
858 | "with for uid %d and gid %d", fd, function, (int) uid, (int) gid); | |
859 | ||
860 | data.fd = fd; | |
861 | ||
862 | strncpy(data.u.extract_elf_symbol_offset.function, function, LTTNG_SYMBOL_NAME_LEN - 1); | |
863 | ||
864 | data.u.extract_elf_symbol_offset.function[LTTNG_SYMBOL_NAME_LEN - 1] = '\0'; | |
865 | ||
866 | run_as(RUN_AS_EXTRACT_ELF_SYMBOL_OFFSET, &data, &ret, uid, gid); | |
867 | ||
868 | errno = ret._errno; | |
869 | ||
870 | if (ret._error) { | |
871 | return -1; | |
872 | } | |
873 | ||
874 | *offset = ret.u.extract_elf_symbol_offset.offset; | |
875 | return 0; | |
876 | } | |
877 | ||
f8f66d38 | 878 | static |
a80ed305 | 879 | int reset_sighandler(void) |
f8f66d38 | 880 | { |
5b5bb8c8 | 881 | int sig; |
f8f66d38 | 882 | |
978d5d79 | 883 | DBG("Resetting run_as worker signal handlers to default"); |
5b5bb8c8 JG |
884 | for (sig = 1; sig <= 31; sig++) { |
885 | (void) signal(sig, SIG_DFL); | |
f8f66d38 | 886 | } |
5b5bb8c8 | 887 | return 0; |
a80ed305 JG |
888 | } |
889 | ||
890 | static | |
891 | void worker_sighandler(int sig) | |
892 | { | |
893 | const char *signame; | |
894 | ||
895 | /* | |
cd89f030 JG |
896 | * The worker will inherit its parent's signals since they are part of |
897 | * the same process group. However, in the case of SIGINT and SIGTERM, | |
898 | * we want to give the worker a chance to teardown gracefully when its | |
899 | * parent closes the command socket. | |
a80ed305 JG |
900 | */ |
901 | switch (sig) { | |
902 | case SIGINT: | |
903 | signame = "SIGINT"; | |
904 | break; | |
905 | case SIGTERM: | |
906 | signame = "SIGTERM"; | |
907 | break; | |
908 | default: | |
22d5e48e | 909 | signame = NULL; |
a80ed305 JG |
910 | } |
911 | ||
22d5e48e JG |
912 | if (signame) { |
913 | DBG("run_as worker received signal %s", signame); | |
914 | } else { | |
915 | DBG("run_as_worker received signal %d", sig); | |
916 | } | |
a80ed305 JG |
917 | } |
918 | ||
919 | static | |
920 | int set_worker_sighandlers(void) | |
921 | { | |
922 | int ret = 0; | |
923 | sigset_t sigset; | |
924 | struct sigaction sa; | |
925 | ||
926 | if ((ret = sigemptyset(&sigset)) < 0) { | |
927 | PERROR("sigemptyset"); | |
928 | goto end; | |
929 | } | |
930 | ||
931 | sa.sa_handler = worker_sighandler; | |
932 | sa.sa_mask = sigset; | |
933 | sa.sa_flags = 0; | |
934 | if ((ret = sigaction(SIGINT, &sa, NULL)) < 0) { | |
935 | PERROR("sigaction SIGINT"); | |
936 | goto end; | |
937 | } | |
938 | ||
939 | if ((ret = sigaction(SIGTERM, &sa, NULL)) < 0) { | |
940 | PERROR("sigaction SIGTERM"); | |
941 | goto end; | |
942 | } | |
943 | ||
944 | DBG("run_as signal handler set for SIGTERM and SIGINT"); | |
945 | end: | |
946 | return ret; | |
f8f66d38 JG |
947 | } |
948 | ||
7567352f MD |
949 | LTTNG_HIDDEN |
950 | int run_as_create_worker(char *procname) | |
951 | { | |
952 | pid_t pid; | |
953 | int i, ret = 0; | |
954 | ssize_t readlen; | |
955 | struct run_as_ret recvret; | |
956 | struct run_as_worker *worker; | |
957 | ||
749b7a0c JG |
958 | pthread_mutex_lock(&worker_lock); |
959 | assert(!global_worker); | |
7567352f | 960 | if (!use_clone()) { |
749b7a0c JG |
961 | /* |
962 | * Don't initialize a worker, all run_as tasks will be performed | |
963 | * in the current process. | |
964 | */ | |
7567352f MD |
965 | ret = 0; |
966 | goto end; | |
967 | } | |
968 | worker = zmalloc(sizeof(*worker)); | |
969 | if (!worker) { | |
970 | ret = -ENOMEM; | |
971 | goto end; | |
972 | } | |
973 | worker->procname = procname; | |
974 | /* Create unix socket. */ | |
975 | if (lttcomm_create_anon_unix_socketpair(worker->sockpair) < 0) { | |
976 | ret = -1; | |
977 | goto error_sock; | |
978 | } | |
fe9f7760 | 979 | |
7567352f MD |
980 | /* Fork worker. */ |
981 | pid = fork(); | |
982 | if (pid < 0) { | |
983 | PERROR("fork"); | |
984 | ret = -1; | |
985 | goto error_fork; | |
986 | } else if (pid == 0) { | |
987 | /* Child */ | |
988 | ||
f8f66d38 JG |
989 | reset_sighandler(); |
990 | ||
a80ed305 JG |
991 | set_worker_sighandlers(); |
992 | ||
749b7a0c JG |
993 | /* The child has no use for this lock. */ |
994 | pthread_mutex_unlock(&worker_lock); | |
7567352f MD |
995 | /* Just close, no shutdown. */ |
996 | if (close(worker->sockpair[0])) { | |
997 | PERROR("close"); | |
998 | exit(EXIT_FAILURE); | |
999 | } | |
fe9f7760 FD |
1000 | |
1001 | /* | |
1002 | * Close all FDs aside from STDIN, STDOUT, STDERR and sockpair[1] | |
1003 | * Sockpair[1] is used as a control channel with the master | |
1004 | */ | |
1005 | for (i = 3; i < sysconf(_SC_OPEN_MAX); i++) { | |
1006 | if (i != worker->sockpair[1]) { | |
1007 | (void) close(i); | |
1008 | } | |
1009 | } | |
1010 | ||
7567352f MD |
1011 | worker->sockpair[0] = -1; |
1012 | ret = run_as_worker(worker); | |
1013 | if (lttcomm_close_unix_sock(worker->sockpair[1])) { | |
1014 | PERROR("close"); | |
1015 | ret = -1; | |
1016 | } | |
1017 | worker->sockpair[1] = -1; | |
978d5d79 | 1018 | LOG(ret ? PRINT_ERR : PRINT_DBG, "run_as worker exiting (ret = %d)", ret); |
7567352f MD |
1019 | exit(ret ? EXIT_FAILURE : EXIT_SUCCESS); |
1020 | } else { | |
1021 | /* Parent */ | |
1022 | ||
1023 | /* Just close, no shutdown. */ | |
1024 | if (close(worker->sockpair[1])) { | |
1025 | PERROR("close"); | |
1026 | ret = -1; | |
1027 | goto error_fork; | |
1028 | } | |
1029 | worker->sockpair[1] = -1; | |
1030 | worker->pid = pid; | |
1031 | /* Wait for worker to become ready. */ | |
1032 | readlen = lttcomm_recv_unix_sock(worker->sockpair[0], | |
1033 | &recvret, sizeof(recvret)); | |
1034 | if (readlen < sizeof(recvret)) { | |
1035 | ERR("readlen: %zd", readlen); | |
1036 | PERROR("Error reading response from run_as at creation"); | |
1037 | ret = -1; | |
1038 | goto error_fork; | |
1039 | } | |
1040 | global_worker = worker; | |
1041 | } | |
1042 | end: | |
749b7a0c | 1043 | pthread_mutex_unlock(&worker_lock); |
7567352f MD |
1044 | return ret; |
1045 | ||
1046 | /* Error handling. */ | |
1047 | error_fork: | |
1048 | for (i = 0; i < 2; i++) { | |
1049 | if (worker->sockpair[i] < 0) { | |
1050 | continue; | |
1051 | } | |
1052 | if (lttcomm_close_unix_sock(worker->sockpair[i])) { | |
1053 | PERROR("close"); | |
1054 | } | |
1055 | worker->sockpair[i] = -1; | |
1056 | } | |
1057 | error_sock: | |
1058 | free(worker); | |
749b7a0c | 1059 | pthread_mutex_unlock(&worker_lock); |
7567352f MD |
1060 | return ret; |
1061 | } | |
1062 | ||
1063 | LTTNG_HIDDEN | |
1064 | void run_as_destroy_worker(void) | |
1065 | { | |
1066 | struct run_as_worker *worker = global_worker; | |
7567352f | 1067 | |
978d5d79 | 1068 | DBG("Destroying run_as worker"); |
749b7a0c | 1069 | pthread_mutex_lock(&worker_lock); |
7567352f | 1070 | if (!worker) { |
749b7a0c | 1071 | goto end; |
7567352f MD |
1072 | } |
1073 | /* Close unix socket */ | |
978d5d79 | 1074 | DBG("Closing run_as worker socket"); |
7567352f MD |
1075 | if (lttcomm_close_unix_sock(worker->sockpair[0])) { |
1076 | PERROR("close"); | |
1077 | } | |
1078 | worker->sockpair[0] = -1; | |
1079 | /* Wait for worker. */ | |
f8f66d38 JG |
1080 | for (;;) { |
1081 | int status; | |
1082 | pid_t wait_ret; | |
1083 | ||
1084 | wait_ret = waitpid(worker->pid, &status, 0); | |
1085 | if (wait_ret < 0) { | |
1086 | if (errno == EINTR) { | |
1087 | continue; | |
1088 | } | |
1089 | PERROR("waitpid"); | |
1090 | break; | |
1091 | } | |
1092 | ||
1093 | if (WIFEXITED(status)) { | |
1094 | LOG(WEXITSTATUS(status) == 0 ? PRINT_DBG : PRINT_ERR, | |
1095 | DEFAULT_RUN_AS_WORKER_NAME " terminated with status code %d", | |
1096 | WEXITSTATUS(status)); | |
1097 | break; | |
1098 | } else if (WIFSIGNALED(status)) { | |
1099 | ERR(DEFAULT_RUN_AS_WORKER_NAME " was killed by signal %d", | |
1100 | WTERMSIG(status)); | |
1101 | break; | |
1102 | } | |
7567352f MD |
1103 | } |
1104 | free(worker); | |
1105 | global_worker = NULL; | |
749b7a0c JG |
1106 | end: |
1107 | pthread_mutex_unlock(&worker_lock); | |
4628484a | 1108 | } |