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1 | /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ | |
2 | ||
3 | /*** | |
4 | This file is part of systemd. | |
5 | ||
6 | Copyright 2010 Lennart Poettering | |
7 | ||
8 | systemd is free software; you can redistribute it and/or modify it | |
9 | under the terms of the GNU Lesser General Public License as published by | |
10 | the Free Software Foundation; either version 2.1 of the License, or | |
11 | (at your option) any later version. | |
12 | ||
13 | systemd is distributed in the hope that it will be useful, but | |
14 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | Lesser General Public License for more details. | |
17 | ||
18 | You should have received a copy of the GNU Lesser General Public License | |
19 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
20 | ***/ | |
21 | ||
22 | #include <sys/mount.h> | |
23 | #include <errno.h> | |
24 | #include <sys/stat.h> | |
25 | #include <stdlib.h> | |
26 | #include <string.h> | |
27 | #include <libgen.h> | |
28 | #include <assert.h> | |
29 | #include <unistd.h> | |
30 | #include <ftw.h> | |
31 | ||
32 | #include "mount-setup.h" | |
33 | #include "dev-setup.h" | |
34 | #include "log.h" | |
35 | #include "macro.h" | |
36 | #include "util.h" | |
37 | #include "label.h" | |
38 | #include "set.h" | |
39 | #include "strv.h" | |
40 | #include "mkdir.h" | |
41 | #include "path-util.h" | |
42 | #include "missing.h" | |
43 | #include "virt.h" | |
44 | #include "efivars.h" | |
45 | #include "smack-util.h" | |
46 | #include "def.h" | |
47 | ||
48 | typedef enum MountMode { | |
49 | MNT_NONE = 0, | |
50 | MNT_FATAL = 1 << 0, | |
51 | MNT_IN_CONTAINER = 1 << 1, | |
52 | } MountMode; | |
53 | ||
54 | typedef struct MountPoint { | |
55 | const char *what; | |
56 | const char *where; | |
57 | const char *type; | |
58 | const char *options; | |
59 | unsigned long flags; | |
60 | bool (*condition_fn)(void); | |
61 | MountMode mode; | |
62 | } MountPoint; | |
63 | ||
64 | /* The first three entries we might need before SELinux is up. The | |
65 | * fourth (securityfs) is needed by IMA to load a custom policy. The | |
66 | * other ones we can delay until SELinux and IMA are loaded. When | |
67 | * SMACK is enabled we need smackfs, too, so it's a fifth one. */ | |
68 | #ifdef HAVE_SMACK | |
69 | #define N_EARLY_MOUNT 5 | |
70 | #else | |
71 | #define N_EARLY_MOUNT 4 | |
72 | #endif | |
73 | ||
74 | static const MountPoint mount_table[] = { | |
75 | { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
76 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
77 | { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
78 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
79 | { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, | |
80 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
81 | { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
82 | NULL, MNT_NONE }, | |
83 | #ifdef HAVE_SMACK | |
84 | { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
85 | mac_smack_use, MNT_FATAL }, | |
86 | { "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
87 | mac_smack_use, MNT_FATAL }, | |
88 | #endif | |
89 | { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
90 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
91 | { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, | |
92 | NULL, MNT_IN_CONTAINER }, | |
93 | #ifdef HAVE_SMACK | |
94 | { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
95 | mac_smack_use, MNT_FATAL }, | |
96 | #endif | |
97 | { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
98 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
99 | { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, | |
100 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
101 | { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
102 | NULL, MNT_IN_CONTAINER }, | |
103 | { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
104 | NULL, MNT_FATAL|MNT_IN_CONTAINER }, | |
105 | { "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
106 | NULL, MNT_NONE }, | |
107 | #ifdef ENABLE_EFI | |
108 | { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
109 | is_efi_boot, MNT_NONE }, | |
110 | #endif | |
111 | #ifdef ENABLE_KDBUS | |
112 | { "kdbusfs", "/sys/fs/kdbus", "kdbusfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
113 | NULL, MNT_IN_CONTAINER }, | |
114 | #endif | |
115 | }; | |
116 | ||
117 | /* These are API file systems that might be mounted by other software, | |
118 | * we just list them here so that we know that we should ignore them */ | |
119 | ||
120 | static const char ignore_paths[] = | |
121 | /* SELinux file systems */ | |
122 | "/sys/fs/selinux\0" | |
123 | "/selinux\0" | |
124 | /* Legacy cgroup mount points */ | |
125 | "/dev/cgroup\0" | |
126 | "/cgroup\0" | |
127 | /* Legacy kernel file system */ | |
128 | "/proc/bus/usb\0" | |
129 | /* Container bind mounts */ | |
130 | "/proc/sys\0" | |
131 | "/dev/console\0" | |
132 | "/proc/kmsg\0"; | |
133 | ||
134 | bool mount_point_is_api(const char *path) { | |
135 | unsigned i; | |
136 | ||
137 | /* Checks if this mount point is considered "API", and hence | |
138 | * should be ignored */ | |
139 | ||
140 | for (i = 0; i < ELEMENTSOF(mount_table); i ++) | |
141 | if (path_equal(path, mount_table[i].where)) | |
142 | return true; | |
143 | ||
144 | return path_startswith(path, "/sys/fs/cgroup/"); | |
145 | } | |
146 | ||
147 | bool mount_point_ignore(const char *path) { | |
148 | const char *i; | |
149 | ||
150 | NULSTR_FOREACH(i, ignore_paths) | |
151 | if (path_equal(path, i)) | |
152 | return true; | |
153 | ||
154 | return false; | |
155 | } | |
156 | ||
157 | static int mount_one(const MountPoint *p, bool relabel) { | |
158 | int r; | |
159 | ||
160 | assert(p); | |
161 | ||
162 | if (p->condition_fn && !p->condition_fn()) | |
163 | return 0; | |
164 | ||
165 | /* Relabel first, just in case */ | |
166 | if (relabel) | |
167 | label_fix(p->where, true, true); | |
168 | ||
169 | r = path_is_mount_point(p->where, true); | |
170 | if (r < 0) | |
171 | return r; | |
172 | ||
173 | if (r > 0) | |
174 | return 0; | |
175 | ||
176 | /* Skip securityfs in a container */ | |
177 | if (!(p->mode & MNT_IN_CONTAINER) && detect_container(NULL) > 0) | |
178 | return 0; | |
179 | ||
180 | /* The access mode here doesn't really matter too much, since | |
181 | * the mounted file system will take precedence anyway. */ | |
182 | if (relabel) | |
183 | mkdir_p_label(p->where, 0755); | |
184 | else | |
185 | mkdir_p(p->where, 0755); | |
186 | ||
187 | log_debug("Mounting %s to %s of type %s with options %s.", | |
188 | p->what, | |
189 | p->where, | |
190 | p->type, | |
191 | strna(p->options)); | |
192 | ||
193 | if (mount(p->what, | |
194 | p->where, | |
195 | p->type, | |
196 | p->flags, | |
197 | p->options) < 0) { | |
198 | log_full((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, "Failed to mount %s at %s: %m", p->type, p->where); | |
199 | return (p->mode & MNT_FATAL) ? -errno : 0; | |
200 | } | |
201 | ||
202 | /* Relabel again, since we now mounted something fresh here */ | |
203 | if (relabel) | |
204 | label_fix(p->where, false, false); | |
205 | ||
206 | return 1; | |
207 | } | |
208 | ||
209 | int mount_setup_early(void) { | |
210 | unsigned i; | |
211 | int r = 0; | |
212 | ||
213 | assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table)); | |
214 | ||
215 | /* Do a minimal mount of /proc and friends to enable the most | |
216 | * basic stuff, such as SELinux */ | |
217 | for (i = 0; i < N_EARLY_MOUNT; i ++) { | |
218 | int j; | |
219 | ||
220 | j = mount_one(mount_table + i, false); | |
221 | if (r == 0) | |
222 | r = j; | |
223 | } | |
224 | ||
225 | return r; | |
226 | } | |
227 | ||
228 | int mount_cgroup_controllers(char ***join_controllers) { | |
229 | _cleanup_set_free_free_ Set *controllers = NULL; | |
230 | _cleanup_fclose_ FILE *f; | |
231 | char buf[LINE_MAX]; | |
232 | int r; | |
233 | ||
234 | /* Mount all available cgroup controllers that are built into the kernel. */ | |
235 | ||
236 | f = fopen("/proc/cgroups", "re"); | |
237 | if (!f) { | |
238 | log_error_errno(errno, "Failed to enumerate cgroup controllers: %m"); | |
239 | return 0; | |
240 | } | |
241 | ||
242 | controllers = set_new(&string_hash_ops); | |
243 | if (!controllers) | |
244 | return log_oom(); | |
245 | ||
246 | /* Ignore the header line */ | |
247 | (void) fgets(buf, sizeof(buf), f); | |
248 | ||
249 | for (;;) { | |
250 | char *controller; | |
251 | int enabled = 0; | |
252 | ||
253 | if (fscanf(f, "%ms %*i %*i %i", &controller, &enabled) != 2) { | |
254 | ||
255 | if (feof(f)) | |
256 | break; | |
257 | ||
258 | log_error("Failed to parse /proc/cgroups."); | |
259 | return -EIO; | |
260 | } | |
261 | ||
262 | if (!enabled) { | |
263 | free(controller); | |
264 | continue; | |
265 | } | |
266 | ||
267 | r = set_consume(controllers, controller); | |
268 | if (r < 0) { | |
269 | log_error("Failed to add controller to set."); | |
270 | return r; | |
271 | } | |
272 | } | |
273 | ||
274 | for (;;) { | |
275 | _cleanup_free_ char *options = NULL, *controller = NULL, *where = NULL; | |
276 | MountPoint p = { | |
277 | .what = "cgroup", | |
278 | .type = "cgroup", | |
279 | .flags = MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
280 | .mode = MNT_IN_CONTAINER, | |
281 | }; | |
282 | char ***k = NULL; | |
283 | ||
284 | controller = set_steal_first(controllers); | |
285 | if (!controller) | |
286 | break; | |
287 | ||
288 | if (join_controllers) | |
289 | for (k = join_controllers; *k; k++) | |
290 | if (strv_find(*k, controller)) | |
291 | break; | |
292 | ||
293 | if (k && *k) { | |
294 | char **i, **j; | |
295 | ||
296 | for (i = *k, j = *k; *i; i++) { | |
297 | ||
298 | if (!streq(*i, controller)) { | |
299 | _cleanup_free_ char *t; | |
300 | ||
301 | t = set_remove(controllers, *i); | |
302 | if (!t) { | |
303 | free(*i); | |
304 | continue; | |
305 | } | |
306 | } | |
307 | ||
308 | *(j++) = *i; | |
309 | } | |
310 | ||
311 | *j = NULL; | |
312 | ||
313 | options = strv_join(*k, ","); | |
314 | if (!options) | |
315 | return log_oom(); | |
316 | } else { | |
317 | options = controller; | |
318 | controller = NULL; | |
319 | } | |
320 | ||
321 | where = strappend("/sys/fs/cgroup/", options); | |
322 | if (!where) | |
323 | return log_oom(); | |
324 | ||
325 | p.where = where; | |
326 | p.options = options; | |
327 | ||
328 | r = mount_one(&p, true); | |
329 | if (r < 0) | |
330 | return r; | |
331 | ||
332 | if (r > 0 && k && *k) { | |
333 | char **i; | |
334 | ||
335 | for (i = *k; *i; i++) { | |
336 | _cleanup_free_ char *t = NULL; | |
337 | ||
338 | t = strappend("/sys/fs/cgroup/", *i); | |
339 | if (!t) | |
340 | return log_oom(); | |
341 | ||
342 | r = symlink(options, t); | |
343 | if (r < 0 && errno != EEXIST) { | |
344 | log_error_errno(errno, "Failed to create symlink %s: %m", t); | |
345 | return -errno; | |
346 | } | |
347 | } | |
348 | } | |
349 | } | |
350 | ||
351 | /* Now that we mounted everything, let's make the tmpfs the | |
352 | * cgroup file systems are mounted into read-only. */ | |
353 | mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); | |
354 | ||
355 | return 0; | |
356 | } | |
357 | ||
358 | #if defined(HAVE_SELINUX) || defined(HAVE_SMACK) | |
359 | static int nftw_cb( | |
360 | const char *fpath, | |
361 | const struct stat *sb, | |
362 | int tflag, | |
363 | struct FTW *ftwbuf) { | |
364 | ||
365 | /* No need to label /dev twice in a row... */ | |
366 | if (_unlikely_(ftwbuf->level == 0)) | |
367 | return FTW_CONTINUE; | |
368 | ||
369 | label_fix(fpath, false, false); | |
370 | ||
371 | /* /run/initramfs is static data and big, no need to | |
372 | * dynamically relabel its contents at boot... */ | |
373 | if (_unlikely_(ftwbuf->level == 1 && | |
374 | tflag == FTW_D && | |
375 | streq(fpath, "/run/initramfs"))) | |
376 | return FTW_SKIP_SUBTREE; | |
377 | ||
378 | return FTW_CONTINUE; | |
379 | }; | |
380 | #endif | |
381 | ||
382 | int mount_setup(bool loaded_policy) { | |
383 | unsigned i; | |
384 | int r = 0; | |
385 | ||
386 | for (i = 0; i < ELEMENTSOF(mount_table); i ++) { | |
387 | int j; | |
388 | ||
389 | j = mount_one(mount_table + i, loaded_policy); | |
390 | if (r == 0) | |
391 | r = j; | |
392 | } | |
393 | ||
394 | if (r < 0) | |
395 | return r; | |
396 | ||
397 | #if defined(HAVE_SELINUX) || defined(HAVE_SMACK) | |
398 | /* Nodes in devtmpfs and /run need to be manually updated for | |
399 | * the appropriate labels, after mounting. The other virtual | |
400 | * API file systems like /sys and /proc do not need that, they | |
401 | * use the same label for all their files. */ | |
402 | if (loaded_policy) { | |
403 | usec_t before_relabel, after_relabel; | |
404 | char timespan[FORMAT_TIMESPAN_MAX]; | |
405 | ||
406 | before_relabel = now(CLOCK_MONOTONIC); | |
407 | ||
408 | nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); | |
409 | nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); | |
410 | ||
411 | after_relabel = now(CLOCK_MONOTONIC); | |
412 | ||
413 | log_info("Relabelled /dev and /run in %s.", | |
414 | format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel, 0)); | |
415 | } | |
416 | #endif | |
417 | ||
418 | /* Create a few default symlinks, which are normally created | |
419 | * by udevd, but some scripts might need them before we start | |
420 | * udevd. */ | |
421 | dev_setup(NULL); | |
422 | ||
423 | /* Mark the root directory as shared in regards to mount | |
424 | * propagation. The kernel defaults to "private", but we think | |
425 | * it makes more sense to have a default of "shared" so that | |
426 | * nspawn and the container tools work out of the box. If | |
427 | * specific setups need other settings they can reset the | |
428 | * propagation mode to private if needed. */ | |
429 | if (detect_container(NULL) <= 0) | |
430 | if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0) | |
431 | log_warning_errno(errno, "Failed to set up the root directory for shared mount propagation: %m"); | |
432 | ||
433 | /* Create a few directories we always want around, Note that | |
434 | * sd_booted() checks for /run/systemd/system, so this mkdir | |
435 | * really needs to stay for good, otherwise software that | |
436 | * copied sd-daemon.c into their sources will misdetect | |
437 | * systemd. */ | |
438 | mkdir_label("/run/systemd", 0755); | |
439 | mkdir_label("/run/systemd/system", 0755); | |
440 | mkdir_label("/run/systemd/inaccessible", 0000); | |
441 | ||
442 | return 0; | |
443 | } |