Commit | Line | Data |
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18710679 JG |
1 | /* |
2 | * Copyright (C) 2019 - Jérémie Galarneau <jeremie.galarneau@efficios.com> | |
3 | * | |
4 | * This program is free software; you can redistribute it and/or modify | |
5 | * it under the terms of the GNU General Public License, version 2 only, | |
6 | * as published by the Free Software Foundation. | |
7 | * | |
8 | * This program is distributed in the hope that it will be useful, but WITHOUT | |
9 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
10 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
11 | * more details. | |
12 | * | |
13 | * You should have received a copy of the GNU General Public License along | |
14 | * with this program; if not, write to the Free Software Foundation, Inc., | |
15 | * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. | |
16 | */ | |
17 | ||
18 | #include <common/compat/directory-handle.h> | |
19 | #include <common/error.h> | |
20 | #include <common/macros.h> | |
21 | #include <common/runas.h> | |
22 | #include <common/credentials.h> | |
23 | #include <lttng/constant.h> | |
24 | ||
25 | #include <assert.h> | |
26 | #include <sys/types.h> | |
27 | #include <sys/stat.h> | |
28 | #include <fcntl.h> | |
29 | #include <unistd.h> | |
30 | ||
31 | static | |
32 | int lttng_directory_handle_stat(const struct lttng_directory_handle *handle, | |
33 | const char *path, struct stat *st); | |
34 | static | |
35 | int lttng_directory_handle_mkdir( | |
36 | const struct lttng_directory_handle *handle, | |
37 | const char *path, mode_t mode); | |
38 | static | |
39 | int _run_as_mkdir(const struct lttng_directory_handle *handle, const char *path, | |
40 | mode_t mode, uid_t uid, gid_t gid); | |
41 | static | |
42 | int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle, | |
43 | const char *path, mode_t mode, uid_t uid, gid_t gid); | |
44 | ||
45 | #ifdef COMPAT_DIRFD | |
46 | ||
47 | LTTNG_HIDDEN | |
48 | int lttng_directory_handle_init(struct lttng_directory_handle *handle, | |
49 | const char *path) | |
50 | { | |
51 | int ret; | |
52 | ||
53 | if (!path) { | |
54 | handle->dirfd = AT_FDCWD; | |
55 | ret = 0; | |
56 | goto end; | |
57 | } | |
58 | ret = open(path, O_RDONLY | O_DIRECTORY | O_CLOEXEC); | |
59 | if (ret == -1) { | |
60 | PERROR("Failed to initialize directory handle to \"%s\"", path); | |
61 | goto end; | |
62 | } | |
63 | handle->dirfd = ret; | |
64 | ret = 0; | |
65 | end: | |
66 | return ret; | |
67 | } | |
68 | ||
69 | LTTNG_HIDDEN | |
70 | int lttng_directory_handle_init_from_dirfd( | |
71 | struct lttng_directory_handle *handle, int dirfd) | |
72 | { | |
73 | handle->dirfd = dirfd; | |
74 | return 0; | |
75 | } | |
76 | ||
77 | LTTNG_HIDDEN | |
78 | void lttng_directory_handle_fini(struct lttng_directory_handle *handle) | |
79 | { | |
80 | int ret; | |
81 | ||
82 | if (handle->dirfd == AT_FDCWD) { | |
83 | return; | |
84 | } | |
85 | ret = close(handle->dirfd); | |
86 | if (ret == -1) { | |
87 | PERROR("Failed to close directory file descriptor of directory handle"); | |
88 | } | |
89 | } | |
90 | ||
578e21bd JG |
91 | LTTNG_HIDDEN |
92 | int lttng_directory_handle_copy(const struct lttng_directory_handle *handle, | |
93 | struct lttng_directory_handle *new_copy) | |
94 | { | |
95 | int ret = 0; | |
96 | ||
97 | if (handle->dirfd == AT_FDCWD) { | |
98 | new_copy->dirfd = handle->dirfd; | |
99 | } else { | |
100 | new_copy->dirfd = dup(handle->dirfd); | |
101 | if (new_copy->dirfd == -1) { | |
102 | PERROR("Failed to duplicate directory fd of directory handle"); | |
103 | ret = -1; | |
104 | } | |
105 | } | |
106 | return ret; | |
107 | } | |
108 | ||
18710679 JG |
109 | static |
110 | int lttng_directory_handle_stat(const struct lttng_directory_handle *handle, | |
111 | const char *path, struct stat *st) | |
112 | { | |
113 | return fstatat(handle->dirfd, path, st, 0); | |
114 | } | |
115 | ||
116 | static | |
117 | int lttng_directory_handle_mkdir( | |
118 | const struct lttng_directory_handle *handle, | |
119 | const char *path, mode_t mode) | |
120 | { | |
121 | return mkdirat(handle->dirfd, path, mode); | |
122 | } | |
123 | ||
124 | static | |
125 | int _run_as_mkdir(const struct lttng_directory_handle *handle, const char *path, | |
126 | mode_t mode, uid_t uid, gid_t gid) | |
127 | { | |
128 | return run_as_mkdirat(handle->dirfd, path, mode, uid, gid); | |
129 | } | |
130 | ||
131 | static | |
132 | int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle, | |
133 | const char *path, mode_t mode, uid_t uid, gid_t gid) | |
134 | { | |
135 | return run_as_mkdirat_recursive(handle->dirfd, path, mode, uid, gid); | |
136 | } | |
137 | ||
138 | #else /* COMPAT_DIRFD */ | |
139 | ||
140 | LTTNG_HIDDEN | |
141 | int lttng_directory_handle_init(struct lttng_directory_handle *handle, | |
142 | const char *path) | |
143 | { | |
144 | int ret; | |
145 | size_t cwd_len, path_len, handle_path_len; | |
146 | char cwd_buf[LTTNG_PATH_MAX]; | |
147 | const char *cwd; | |
148 | bool add_slash = false; | |
149 | struct stat stat_buf; | |
150 | ||
151 | cwd = getcwd(cwd_buf, sizeof(cwd_buf)); | |
152 | if (!cwd) { | |
153 | PERROR("Failed to initialize directory handle, can't get current working directory"); | |
154 | ret = -1; | |
155 | goto end; | |
156 | } | |
157 | cwd_len = strlen(cwd); | |
158 | if (cwd_len == 0) { | |
159 | ERR("Failed to initialize directory handle to \"%s\": getcwd() returned an empty string", | |
160 | path); | |
161 | ret = -1; | |
162 | goto end; | |
163 | } | |
164 | if (cwd[cwd_len - 1] != '/') { | |
165 | add_slash = true; | |
166 | } | |
167 | ||
168 | if (path) { | |
169 | path_len = strlen(path); | |
170 | if (path_len == 0) { | |
171 | ERR("Failed to initialize directory handle: provided path is an empty string"); | |
172 | ret = -1; | |
173 | goto end; | |
174 | } | |
175 | ||
176 | /* | |
177 | * Ensure that 'path' is a directory. There is a race | |
178 | * (TOCTOU) since the directory could be removed/replaced/renamed, | |
179 | * but this is inevitable on platforms that don't provide dirfd support. | |
180 | */ | |
181 | ret = stat(path, &stat_buf); | |
182 | if (ret == -1) { | |
183 | PERROR("Failed to initialize directory handle to \"%s\", stat() failed", | |
184 | path); | |
185 | goto end; | |
186 | } | |
187 | if (!S_ISDIR(stat_buf.st_mode)) { | |
188 | ERR("Failed to initialize directory handle to \"%s\": not a directory", | |
189 | path); | |
190 | ret = -1; | |
191 | goto end; | |
192 | } | |
193 | if (*path == '/') { | |
194 | handle->base_path = strdup(path); | |
195 | if (!handle->base_path) { | |
196 | ret = -1; | |
197 | } | |
198 | /* Not an error. */ | |
199 | goto end; | |
200 | } | |
201 | } else { | |
202 | path = ""; | |
203 | path_len = 0; | |
204 | add_slash = false; | |
205 | } | |
206 | ||
207 | handle_path_len = cwd_len + path_len + !!add_slash + 2; | |
208 | if (handle_path_len >= LTTNG_PATH_MAX) { | |
209 | ERR("Failed to initialize directory handle as the resulting path's length (%zu bytes) exceeds the maximal allowed length (%d bytes)", | |
210 | handle_path_len, LTTNG_PATH_MAX); | |
211 | ret = -1; | |
212 | goto end; | |
213 | } | |
214 | handle->base_path = zmalloc(handle_path_len); | |
215 | if (!handle->base_path) { | |
216 | PERROR("Failed to initialize directory handle"); | |
217 | ret = -1; | |
218 | goto end; | |
219 | } | |
220 | ||
221 | ret = sprintf(handle->base_path, "%s%s%s/", cwd, | |
222 | add_slash ? "/" : "", path); | |
223 | if (ret == -1 || ret >= handle_path_len) { | |
224 | ERR("Failed to initialize directory handle: path formatting failed"); | |
225 | ret = -1; | |
226 | goto end; | |
227 | } | |
228 | end: | |
229 | return ret; | |
230 | } | |
231 | ||
232 | LTTNG_HIDDEN | |
233 | int lttng_directory_handle_init_from_dirfd( | |
234 | struct lttng_directory_handle *handle, int dirfd) | |
235 | { | |
236 | assert(dirfd == AT_FDCWD); | |
237 | return lttng_directory_handle_init(handle, NULL); | |
238 | } | |
239 | ||
240 | LTTNG_HIDDEN | |
241 | void lttng_directory_handle_fini(struct lttng_directory_handle *handle) | |
242 | { | |
243 | free(handle->base_path); | |
244 | } | |
245 | ||
578e21bd JG |
246 | LTTNG_HIDDEN |
247 | int lttng_directory_handle_copy(const struct lttng_directory_handle *handle, | |
248 | struct lttng_directory_handle *new_copy) | |
249 | { | |
250 | new_copy->base_path = strdup(handle->base_path); | |
251 | return new_copy->base_path ? 0 : -1; | |
252 | } | |
253 | ||
18710679 JG |
254 | static |
255 | int get_full_path(const struct lttng_directory_handle *handle, | |
256 | const char *subdirectory, char *fullpath, size_t size) | |
257 | { | |
258 | int ret; | |
259 | ||
260 | /* | |
261 | * Don't include the base path if subdirectory is absolute. | |
262 | * This is the same behaviour than mkdirat. | |
263 | */ | |
264 | ret = snprintf(fullpath, size, "%s%s", | |
265 | *subdirectory != '/' ? handle->base_path : "", | |
266 | subdirectory); | |
267 | if (ret == -1 || ret >= size) { | |
268 | ERR("Failed to format subdirectory from directory handle"); | |
269 | ret = -1; | |
270 | } | |
271 | ret = 0; | |
272 | return ret; | |
273 | } | |
274 | ||
275 | static | |
276 | int lttng_directory_handle_stat(const struct lttng_directory_handle *handle, | |
277 | const char *subdirectory, struct stat *st) | |
278 | { | |
279 | int ret; | |
280 | char fullpath[LTTNG_PATH_MAX]; | |
281 | ||
282 | ret = get_full_path(handle, subdirectory, fullpath, sizeof(fullpath)); | |
283 | if (ret) { | |
284 | errno = ENOMEM; | |
285 | goto end; | |
286 | } | |
287 | ||
288 | ret = stat(fullpath, st); | |
289 | end: | |
290 | return ret; | |
291 | } | |
292 | ||
293 | static | |
294 | int lttng_directory_handle_mkdir(const struct lttng_directory_handle *handle, | |
295 | const char *subdirectory, mode_t mode) | |
296 | { | |
297 | int ret; | |
298 | char fullpath[LTTNG_PATH_MAX]; | |
299 | ||
300 | ret = get_full_path(handle, subdirectory, fullpath, sizeof(fullpath)); | |
301 | if (ret) { | |
302 | errno = ENOMEM; | |
303 | goto end; | |
304 | } | |
305 | ||
306 | ret = mkdir(fullpath, mode); | |
307 | end: | |
308 | return ret; | |
309 | } | |
310 | ||
311 | static | |
312 | int _run_as_mkdir(const struct lttng_directory_handle *handle, const char *path, | |
313 | mode_t mode, uid_t uid, gid_t gid) | |
314 | { | |
315 | int ret; | |
316 | char fullpath[LTTNG_PATH_MAX]; | |
317 | ||
318 | ret = get_full_path(handle, path, fullpath, sizeof(fullpath)); | |
319 | if (ret) { | |
320 | errno = ENOMEM; | |
321 | goto end; | |
322 | } | |
323 | ||
324 | ret = run_as_mkdir(fullpath, mode, uid, gid); | |
325 | end: | |
326 | return ret; | |
327 | } | |
328 | ||
329 | static | |
330 | int _run_as_mkdir_recursive(const struct lttng_directory_handle *handle, | |
331 | const char *path, mode_t mode, uid_t uid, gid_t gid) | |
332 | { | |
333 | int ret; | |
334 | char fullpath[LTTNG_PATH_MAX]; | |
335 | ||
336 | ret = get_full_path(handle, path, fullpath, sizeof(fullpath)); | |
337 | if (ret) { | |
338 | errno = ENOMEM; | |
339 | goto end; | |
340 | } | |
341 | ||
342 | ret = run_as_mkdir_recursive(fullpath, mode, uid, gid); | |
343 | end: | |
344 | return ret; | |
345 | } | |
346 | ||
347 | #endif /* COMPAT_DIRFD */ | |
348 | ||
349 | /* | |
350 | * On some filesystems (e.g. nfs), mkdir will validate access rights before | |
351 | * checking for the existence of the path element. This means that on a setup | |
352 | * where "/home/" is a mounted NFS share, and running as an unpriviledged user, | |
353 | * recursively creating a path of the form "/home/my_user/trace/" will fail with | |
354 | * EACCES on mkdir("/home", ...). | |
355 | * | |
356 | * Checking the path for existence allows us to work around this behaviour. | |
357 | */ | |
358 | static | |
359 | int create_directory_check_exists(const struct lttng_directory_handle *handle, | |
360 | const char *path, mode_t mode) | |
361 | { | |
362 | int ret = 0; | |
363 | struct stat st; | |
364 | ||
365 | ret = lttng_directory_handle_stat(handle, path, &st); | |
366 | if (ret == 0) { | |
367 | if (S_ISDIR(st.st_mode)) { | |
368 | /* Directory exists, skip. */ | |
369 | goto end; | |
370 | } else { | |
371 | /* Exists, but is not a directory. */ | |
372 | errno = ENOTDIR; | |
373 | ret = -1; | |
374 | goto end; | |
375 | } | |
376 | } | |
377 | ||
378 | /* | |
379 | * Let mkdir handle other errors as the caller expects mkdir | |
380 | * semantics. | |
381 | */ | |
382 | ret = lttng_directory_handle_mkdir(handle, path, mode); | |
383 | end: | |
384 | return ret; | |
385 | } | |
386 | ||
387 | /* Common implementation. */ | |
388 | static | |
389 | int create_directory_recursive(const struct lttng_directory_handle *handle, | |
390 | const char *path, mode_t mode) | |
391 | { | |
392 | char *p, tmp[LTTNG_PATH_MAX]; | |
393 | size_t len; | |
394 | int ret; | |
395 | ||
396 | assert(path); | |
397 | ||
398 | ret = lttng_strncpy(tmp, path, sizeof(tmp)); | |
399 | if (ret) { | |
400 | ERR("Failed to create directory: provided path's length (%zu bytes) exceeds the maximal allowed length (%zu bytes)", | |
401 | strlen(path) + 1, sizeof(tmp)); | |
402 | goto error; | |
403 | } | |
404 | ||
405 | len = strlen(path); | |
406 | if (tmp[len - 1] == '/') { | |
407 | tmp[len - 1] = 0; | |
408 | } | |
409 | ||
410 | for (p = tmp + 1; *p; p++) { | |
411 | if (*p == '/') { | |
412 | *p = 0; | |
413 | if (tmp[strlen(tmp) - 1] == '.' && | |
414 | tmp[strlen(tmp) - 2] == '.' && | |
415 | tmp[strlen(tmp) - 3] == '/') { | |
416 | ERR("Using '/../' is not permitted in the trace path (%s)", | |
417 | tmp); | |
418 | ret = -1; | |
419 | goto error; | |
420 | } | |
421 | ret = create_directory_check_exists(handle, tmp, mode); | |
422 | if (ret < 0) { | |
423 | if (errno != EACCES) { | |
424 | PERROR("Failed to create directory \"%s\"", | |
425 | path); | |
426 | ret = -errno; | |
427 | goto error; | |
428 | } | |
429 | } | |
430 | *p = '/'; | |
431 | } | |
432 | } | |
433 | ||
434 | ret = create_directory_check_exists(handle, tmp, mode); | |
435 | if (ret < 0) { | |
436 | PERROR("mkdirat recursive last element"); | |
437 | ret = -errno; | |
438 | } | |
439 | error: | |
440 | return ret; | |
441 | } | |
442 | ||
443 | LTTNG_HIDDEN | |
444 | int lttng_directory_handle_create_subdirectory_as_user( | |
445 | const struct lttng_directory_handle *handle, | |
446 | const char *subdirectory, | |
69e3a560 | 447 | mode_t mode, const struct lttng_credentials *creds) |
18710679 JG |
448 | { |
449 | int ret; | |
450 | ||
451 | if (!creds) { | |
452 | /* Run as current user. */ | |
453 | ret = create_directory_check_exists(handle, | |
454 | subdirectory, mode); | |
455 | } else { | |
456 | ret = _run_as_mkdir(handle, subdirectory, | |
457 | mode, creds->uid, creds->gid); | |
458 | } | |
459 | ||
460 | return ret; | |
461 | } | |
462 | ||
463 | LTTNG_HIDDEN | |
464 | int lttng_directory_handle_create_subdirectory_recursive_as_user( | |
465 | const struct lttng_directory_handle *handle, | |
466 | const char *subdirectory_path, | |
69e3a560 | 467 | mode_t mode, const struct lttng_credentials *creds) |
18710679 JG |
468 | { |
469 | int ret; | |
470 | ||
471 | if (!creds) { | |
472 | /* Run as current user. */ | |
473 | ret = create_directory_recursive(handle, | |
474 | subdirectory_path, mode); | |
475 | } else { | |
476 | ret = _run_as_mkdir_recursive(handle, subdirectory_path, | |
477 | mode, creds->uid, creds->gid); | |
478 | } | |
479 | ||
480 | return ret; | |
481 | } | |
482 | ||
483 | LTTNG_HIDDEN | |
484 | int lttng_directory_handle_create_subdirectory( | |
485 | const struct lttng_directory_handle *handle, | |
486 | const char *subdirectory, | |
487 | mode_t mode) | |
488 | { | |
489 | return lttng_directory_handle_create_subdirectory_as_user( | |
490 | handle, subdirectory, mode, NULL); | |
491 | } | |
492 | ||
493 | LTTNG_HIDDEN | |
494 | int lttng_directory_handle_create_subdirectory_recursive( | |
495 | const struct lttng_directory_handle *handle, | |
496 | const char *subdirectory_path, | |
497 | mode_t mode) | |
498 | { | |
499 | return lttng_directory_handle_create_subdirectory_recursive_as_user( | |
500 | handle, subdirectory_path, mode, NULL); | |
501 | } |