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15ae422b LP |
1 | /*** |
2 | This file is part of systemd. | |
3 | ||
4 | Copyright 2010 Lennart Poettering | |
5 | ||
6 | systemd is free software; you can redistribute it and/or modify it | |
5430f7f2 LP |
7 | under the terms of the GNU Lesser General Public License as published by |
8 | the Free Software Foundation; either version 2.1 of the License, or | |
15ae422b LP |
9 | (at your option) any later version. |
10 | ||
11 | systemd is distributed in the hope that it will be useful, but | |
12 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
5430f7f2 | 14 | Lesser General Public License for more details. |
15ae422b | 15 | |
5430f7f2 | 16 | You should have received a copy of the GNU Lesser General Public License |
15ae422b LP |
17 | along with systemd; If not, see <http://www.gnu.org/licenses/>. |
18 | ***/ | |
19 | ||
20 | #include <errno.h> | |
07630cea | 21 | #include <sched.h> |
15ae422b | 22 | #include <stdio.h> |
07630cea LP |
23 | #include <string.h> |
24 | #include <sys/mount.h> | |
15ae422b | 25 | #include <sys/stat.h> |
07630cea | 26 | #include <unistd.h> |
25e870b5 | 27 | #include <linux/fs.h> |
15ae422b | 28 | |
b5efdb8a | 29 | #include "alloc-util.h" |
7f112f50 | 30 | #include "dev-setup.h" |
3ffd4af2 | 31 | #include "fd-util.h" |
d944dc95 | 32 | #include "fs-util.h" |
07630cea LP |
33 | #include "loopback-setup.h" |
34 | #include "missing.h" | |
35 | #include "mkdir.h" | |
4349cd7c | 36 | #include "mount-util.h" |
3ffd4af2 | 37 | #include "namespace.h" |
07630cea | 38 | #include "path-util.h" |
d7b8eec7 | 39 | #include "selinux-util.h" |
2583fbea | 40 | #include "socket-util.h" |
8b43440b | 41 | #include "string-table.h" |
07630cea LP |
42 | #include "string-util.h" |
43 | #include "strv.h" | |
affb60b1 | 44 | #include "umask-util.h" |
ee104e11 | 45 | #include "user-util.h" |
07630cea | 46 | #include "util.h" |
15ae422b | 47 | |
737ba3c8 | 48 | #define DEV_MOUNT_OPTIONS (MS_NOSUID|MS_STRICTATIME|MS_NOEXEC) |
49 | ||
c17ec25e | 50 | typedef enum MountMode { |
15ae422b LP |
51 | /* This is ordered by priority! */ |
52 | INACCESSIBLE, | |
53 | READONLY, | |
ac0930c8 LP |
54 | PRIVATE_TMP, |
55 | PRIVATE_VAR_TMP, | |
7f112f50 | 56 | PRIVATE_DEV, |
59eeb84b | 57 | READWRITE, |
c17ec25e | 58 | } MountMode; |
15ae422b | 59 | |
c17ec25e | 60 | typedef struct BindMount { |
d944dc95 LP |
61 | const char *path; /* stack memory, doesn't need to be freed explicitly */ |
62 | char *chased; /* malloc()ed memory, needs to be freed */ | |
c17ec25e | 63 | MountMode mode; |
11a30cec | 64 | bool ignore; /* Ignore if path does not exist */ |
c17ec25e | 65 | } BindMount; |
15ae422b | 66 | |
11a30cec DH |
67 | typedef struct TargetMount { |
68 | const char *path; | |
69 | MountMode mode; | |
70 | bool ignore; /* Ignore if path does not exist */ | |
71 | } TargetMount; | |
72 | ||
f471b2af DH |
73 | /* |
74 | * The following Protect tables are to protect paths and mark some of them | |
75 | * READONLY, in case a path is covered by an option from another table, then | |
76 | * it is marked READWRITE in the current one, and the more restrictive mode is | |
77 | * applied from that other table. This way all options can be combined in a | |
78 | * safe and comprehensible way for users. | |
79 | */ | |
80 | ||
11a30cec DH |
81 | /* ProtectKernelTunables= option and the related filesystem APIs */ |
82 | static const TargetMount protect_kernel_tunables_table[] = { | |
83 | { "/proc/sys", READONLY, false }, | |
84 | { "/proc/sysrq-trigger", READONLY, true }, | |
49accde7 DH |
85 | { "/proc/latency_stats", READONLY, true }, |
86 | { "/proc/mtrr", READONLY, true }, | |
87 | { "/proc/apm", READONLY, true }, | |
88 | { "/proc/acpi", READONLY, true }, | |
89 | { "/proc/timer_stats", READONLY, true }, | |
90 | { "/proc/asound", READONLY, true }, | |
91 | { "/proc/bus", READONLY, true }, | |
92 | { "/proc/fs", READONLY, true }, | |
93 | { "/proc/irq", READONLY, true }, | |
11a30cec | 94 | { "/sys", READONLY, false }, |
49accde7 DH |
95 | { "/sys/kernel/debug", READONLY, true }, |
96 | { "/sys/kernel/tracing", READONLY, true }, | |
11a30cec DH |
97 | { "/sys/fs/cgroup", READWRITE, false }, /* READONLY is set by ProtectControlGroups= option */ |
98 | }; | |
99 | ||
c575770b DH |
100 | /* ProtectKernelModules= option */ |
101 | static const TargetMount protect_kernel_modules_table[] = { | |
102 | #ifdef HAVE_SPLIT_USR | |
103 | { "/lib/modules", INACCESSIBLE, true }, | |
104 | #endif | |
105 | { "/usr/lib/modules", INACCESSIBLE, true }, | |
106 | }; | |
107 | ||
b6c432ca DH |
108 | /* |
109 | * ProtectHome=read-only table, protect $HOME and $XDG_RUNTIME_DIR and rest of | |
110 | * system should be protected by ProtectSystem= | |
111 | */ | |
112 | static const TargetMount protect_home_read_only_table[] = { | |
113 | { "/home", READONLY, true }, | |
114 | { "/run/user", READONLY, true }, | |
115 | { "/root", READONLY, true }, | |
116 | }; | |
117 | ||
118 | /* ProtectHome=yes table */ | |
119 | static const TargetMount protect_home_yes_table[] = { | |
120 | { "/home", INACCESSIBLE, true }, | |
121 | { "/run/user", INACCESSIBLE, true }, | |
122 | { "/root", INACCESSIBLE, true }, | |
123 | }; | |
124 | ||
f471b2af DH |
125 | /* ProtectSystem=yes table */ |
126 | static const TargetMount protect_system_yes_table[] = { | |
127 | { "/usr", READONLY, false }, | |
128 | { "/boot", READONLY, true }, | |
129 | { "/efi", READONLY, true }, | |
130 | }; | |
131 | ||
132 | /* ProtectSystem=full includes ProtectSystem=yes */ | |
133 | static const TargetMount protect_system_full_table[] = { | |
134 | { "/usr", READONLY, false }, | |
135 | { "/boot", READONLY, true }, | |
136 | { "/efi", READONLY, true }, | |
137 | { "/etc", READONLY, false }, | |
138 | }; | |
139 | ||
140 | /* | |
141 | * ProtectSystem=strict table. In this strict mode, we mount everything | |
142 | * read-only, except for /proc, /dev, /sys which are the kernel API VFS, | |
143 | * which are left writable, but PrivateDevices= + ProtectKernelTunables= | |
144 | * protect those, and these options should be fully orthogonal. | |
145 | * (And of course /home and friends are also left writable, as ProtectHome= | |
146 | * shall manage those, orthogonally). | |
147 | */ | |
148 | static const TargetMount protect_system_strict_table[] = { | |
149 | { "/", READONLY, false }, | |
150 | { "/proc", READWRITE, false }, /* ProtectKernelTunables= */ | |
151 | { "/sys", READWRITE, false }, /* ProtectKernelTunables= */ | |
152 | { "/dev", READWRITE, false }, /* PrivateDevices= */ | |
153 | { "/home", READWRITE, true }, /* ProtectHome= */ | |
154 | { "/run/user", READWRITE, true }, /* ProtectHome= */ | |
155 | { "/root", READWRITE, true }, /* ProtectHome= */ | |
156 | }; | |
157 | ||
158 | static void set_bind_mount(BindMount **p, const char *path, MountMode mode, bool ignore) { | |
159 | (*p)->path = path; | |
160 | (*p)->mode = mode; | |
161 | (*p)->ignore = ignore; | |
162 | } | |
163 | ||
c17ec25e | 164 | static int append_mounts(BindMount **p, char **strv, MountMode mode) { |
15ae422b LP |
165 | char **i; |
166 | ||
613b411c LP |
167 | assert(p); |
168 | ||
15ae422b | 169 | STRV_FOREACH(i, strv) { |
9c94d52e | 170 | bool ignore = false; |
15ae422b | 171 | |
9c94d52e | 172 | if (IN_SET(mode, INACCESSIBLE, READONLY, READWRITE) && startswith(*i, "-")) { |
ea92ae33 | 173 | (*i)++; |
9c94d52e | 174 | ignore = true; |
ea92ae33 MW |
175 | } |
176 | ||
15ae422b LP |
177 | if (!path_is_absolute(*i)) |
178 | return -EINVAL; | |
179 | ||
f471b2af | 180 | set_bind_mount(p, *i, mode, ignore); |
15ae422b LP |
181 | (*p)++; |
182 | } | |
183 | ||
184 | return 0; | |
185 | } | |
186 | ||
f471b2af DH |
187 | static int append_target_mounts(BindMount **p, const char *root_directory, const TargetMount *mounts, const size_t size) { |
188 | unsigned i; | |
11a30cec DH |
189 | |
190 | assert(p); | |
f471b2af | 191 | assert(mounts); |
11a30cec | 192 | |
f471b2af DH |
193 | for (i = 0; i < size; i++) { |
194 | /* | |
195 | * Here we assume that the ignore field is set during | |
196 | * declaration we do not support "-" at the beginning. | |
197 | */ | |
198 | const TargetMount *m = &mounts[i]; | |
199 | const char *path = prefix_roota(root_directory, m->path); | |
200 | ||
201 | if (!path_is_absolute(path)) | |
202 | return -EINVAL; | |
203 | ||
204 | set_bind_mount(p, path, m->mode, m->ignore); | |
11a30cec DH |
205 | (*p)++; |
206 | } | |
f471b2af DH |
207 | |
208 | return 0; | |
209 | } | |
210 | ||
211 | static int append_protect_kernel_tunables(BindMount **p, const char *root_directory) { | |
212 | assert(p); | |
213 | ||
214 | return append_target_mounts(p, root_directory, protect_kernel_tunables_table, | |
215 | ELEMENTSOF(protect_kernel_tunables_table)); | |
216 | } | |
217 | ||
c575770b DH |
218 | static int append_protect_kernel_modules(BindMount **p, const char *root_directory) { |
219 | assert(p); | |
220 | ||
221 | return append_target_mounts(p, root_directory, protect_kernel_modules_table, | |
222 | ELEMENTSOF(protect_kernel_modules_table)); | |
223 | } | |
224 | ||
b6c432ca DH |
225 | static int append_protect_home(BindMount **p, const char *root_directory, ProtectHome protect_home) { |
226 | int r = 0; | |
227 | ||
228 | assert(p); | |
229 | ||
230 | if (protect_home == PROTECT_HOME_NO) | |
231 | return 0; | |
232 | ||
233 | switch (protect_home) { | |
234 | case PROTECT_HOME_READ_ONLY: | |
235 | r = append_target_mounts(p, root_directory, protect_home_read_only_table, | |
236 | ELEMENTSOF(protect_home_read_only_table)); | |
237 | break; | |
238 | case PROTECT_HOME_YES: | |
239 | r = append_target_mounts(p, root_directory, protect_home_yes_table, | |
240 | ELEMENTSOF(protect_home_yes_table)); | |
241 | break; | |
242 | default: | |
243 | r = -EINVAL; | |
244 | break; | |
245 | } | |
246 | ||
247 | return r; | |
248 | } | |
249 | ||
f471b2af DH |
250 | static int append_protect_system(BindMount **p, const char *root_directory, ProtectSystem protect_system) { |
251 | int r = 0; | |
252 | ||
253 | assert(p); | |
254 | ||
255 | if (protect_system == PROTECT_SYSTEM_NO) | |
256 | return 0; | |
257 | ||
258 | switch (protect_system) { | |
259 | case PROTECT_SYSTEM_STRICT: | |
260 | r = append_target_mounts(p, root_directory, protect_system_strict_table, | |
261 | ELEMENTSOF(protect_system_strict_table)); | |
262 | break; | |
263 | case PROTECT_SYSTEM_YES: | |
264 | r = append_target_mounts(p, root_directory, protect_system_yes_table, | |
265 | ELEMENTSOF(protect_system_yes_table)); | |
266 | break; | |
267 | case PROTECT_SYSTEM_FULL: | |
268 | r = append_target_mounts(p, root_directory, protect_system_full_table, | |
269 | ELEMENTSOF(protect_system_full_table)); | |
270 | break; | |
271 | default: | |
272 | r = -EINVAL; | |
273 | break; | |
274 | } | |
275 | ||
276 | return r; | |
11a30cec DH |
277 | } |
278 | ||
c17ec25e MS |
279 | static int mount_path_compare(const void *a, const void *b) { |
280 | const BindMount *p = a, *q = b; | |
a0827e2b | 281 | int d; |
15ae422b | 282 | |
6ee1a919 | 283 | /* If the paths are not equal, then order prefixes first */ |
a0827e2b | 284 | d = path_compare(p->path, q->path); |
6ee1a919 LP |
285 | if (d != 0) |
286 | return d; | |
15ae422b | 287 | |
6ee1a919 LP |
288 | /* If the paths are equal, check the mode */ |
289 | if (p->mode < q->mode) | |
290 | return -1; | |
15ae422b | 291 | |
6ee1a919 LP |
292 | if (p->mode > q->mode) |
293 | return 1; | |
15ae422b | 294 | |
6ee1a919 | 295 | return 0; |
15ae422b LP |
296 | } |
297 | ||
c17ec25e MS |
298 | static void drop_duplicates(BindMount *m, unsigned *n) { |
299 | BindMount *f, *t, *previous; | |
15ae422b | 300 | |
c17ec25e | 301 | assert(m); |
15ae422b | 302 | assert(n); |
15ae422b | 303 | |
fe3c2583 LP |
304 | /* Drops duplicate entries. Expects that the array is properly ordered already. */ |
305 | ||
c17ec25e | 306 | for (f = m, t = m, previous = NULL; f < m+*n; f++) { |
15ae422b | 307 | |
fe3c2583 LP |
308 | /* The first one wins (which is the one with the more restrictive mode), see mount_path_compare() |
309 | * above. */ | |
310 | if (previous && path_equal(f->path, previous->path)) { | |
311 | log_debug("%s is duplicate.", f->path); | |
15ae422b | 312 | continue; |
fe3c2583 | 313 | } |
15ae422b | 314 | |
e2d7c1a0 | 315 | *t = *f; |
15ae422b | 316 | previous = t; |
fe3c2583 LP |
317 | t++; |
318 | } | |
319 | ||
320 | *n = t - m; | |
321 | } | |
322 | ||
323 | static void drop_inaccessible(BindMount *m, unsigned *n) { | |
324 | BindMount *f, *t; | |
325 | const char *clear = NULL; | |
326 | ||
327 | assert(m); | |
328 | assert(n); | |
329 | ||
330 | /* Drops all entries obstructed by another entry further up the tree. Expects that the array is properly | |
331 | * ordered already. */ | |
332 | ||
333 | for (f = m, t = m; f < m+*n; f++) { | |
334 | ||
335 | /* If we found a path set for INACCESSIBLE earlier, and this entry has it as prefix we should drop | |
336 | * it, as inaccessible paths really should drop the entire subtree. */ | |
337 | if (clear && path_startswith(f->path, clear)) { | |
338 | log_debug("%s is masked by %s.", f->path, clear); | |
339 | continue; | |
340 | } | |
15ae422b | 341 | |
fe3c2583 LP |
342 | clear = f->mode == INACCESSIBLE ? f->path : NULL; |
343 | ||
344 | *t = *f; | |
15ae422b LP |
345 | t++; |
346 | } | |
347 | ||
c17ec25e | 348 | *n = t - m; |
15ae422b LP |
349 | } |
350 | ||
7648a565 LP |
351 | static void drop_nop(BindMount *m, unsigned *n) { |
352 | BindMount *f, *t; | |
353 | ||
354 | assert(m); | |
355 | assert(n); | |
356 | ||
357 | /* Drops all entries which have an immediate parent that has the same type, as they are redundant. Assumes the | |
358 | * list is ordered by prefixes. */ | |
359 | ||
360 | for (f = m, t = m; f < m+*n; f++) { | |
361 | ||
362 | /* Only suppress such subtrees for READONLY and READWRITE entries */ | |
363 | if (IN_SET(f->mode, READONLY, READWRITE)) { | |
364 | BindMount *p; | |
365 | bool found = false; | |
366 | ||
367 | /* Now let's find the first parent of the entry we are looking at. */ | |
368 | for (p = t-1; p >= m; p--) { | |
369 | if (path_startswith(f->path, p->path)) { | |
370 | found = true; | |
371 | break; | |
372 | } | |
373 | } | |
374 | ||
375 | /* We found it, let's see if it's the same mode, if so, we can drop this entry */ | |
376 | if (found && p->mode == f->mode) { | |
377 | log_debug("%s is redundant by %s", f->path, p->path); | |
378 | continue; | |
379 | } | |
380 | } | |
381 | ||
382 | *t = *f; | |
383 | t++; | |
384 | } | |
385 | ||
386 | *n = t - m; | |
387 | } | |
388 | ||
cd2902c9 LP |
389 | static void drop_outside_root(const char *root_directory, BindMount *m, unsigned *n) { |
390 | BindMount *f, *t; | |
391 | ||
392 | assert(m); | |
393 | assert(n); | |
394 | ||
395 | if (!root_directory) | |
396 | return; | |
397 | ||
398 | /* Drops all mounts that are outside of the root directory. */ | |
399 | ||
400 | for (f = m, t = m; f < m+*n; f++) { | |
401 | ||
402 | if (!path_startswith(f->path, root_directory)) { | |
403 | log_debug("%s is outside of root directory.", f->path); | |
404 | continue; | |
405 | } | |
406 | ||
407 | *t = *f; | |
408 | t++; | |
409 | } | |
410 | ||
411 | *n = t - m; | |
412 | } | |
413 | ||
7f112f50 LP |
414 | static int mount_dev(BindMount *m) { |
415 | static const char devnodes[] = | |
416 | "/dev/null\0" | |
417 | "/dev/zero\0" | |
418 | "/dev/full\0" | |
419 | "/dev/random\0" | |
420 | "/dev/urandom\0" | |
421 | "/dev/tty\0"; | |
422 | ||
2b85f4e1 | 423 | char temporary_mount[] = "/tmp/namespace-dev-XXXXXX"; |
63cc4c31 | 424 | const char *d, *dev = NULL, *devpts = NULL, *devshm = NULL, *devhugepages = NULL, *devmqueue = NULL, *devlog = NULL, *devptmx = NULL; |
7f112f50 LP |
425 | _cleanup_umask_ mode_t u; |
426 | int r; | |
427 | ||
428 | assert(m); | |
429 | ||
430 | u = umask(0000); | |
431 | ||
2b85f4e1 LP |
432 | if (!mkdtemp(temporary_mount)) |
433 | return -errno; | |
434 | ||
63c372cb | 435 | dev = strjoina(temporary_mount, "/dev"); |
dc751688 | 436 | (void) mkdir(dev, 0755); |
737ba3c8 | 437 | if (mount("tmpfs", dev, "tmpfs", DEV_MOUNT_OPTIONS, "mode=755") < 0) { |
2b85f4e1 LP |
438 | r = -errno; |
439 | goto fail; | |
440 | } | |
441 | ||
63c372cb | 442 | devpts = strjoina(temporary_mount, "/dev/pts"); |
dc751688 | 443 | (void) mkdir(devpts, 0755); |
2b85f4e1 LP |
444 | if (mount("/dev/pts", devpts, NULL, MS_BIND, NULL) < 0) { |
445 | r = -errno; | |
446 | goto fail; | |
447 | } | |
448 | ||
63c372cb | 449 | devptmx = strjoina(temporary_mount, "/dev/ptmx"); |
3164e3cb ZJS |
450 | if (symlink("pts/ptmx", devptmx) < 0) { |
451 | r = -errno; | |
452 | goto fail; | |
453 | } | |
e06b6479 | 454 | |
63c372cb | 455 | devshm = strjoina(temporary_mount, "/dev/shm"); |
dc751688 | 456 | (void) mkdir(devshm, 01777); |
2b85f4e1 LP |
457 | r = mount("/dev/shm", devshm, NULL, MS_BIND, NULL); |
458 | if (r < 0) { | |
459 | r = -errno; | |
460 | goto fail; | |
461 | } | |
462 | ||
63c372cb | 463 | devmqueue = strjoina(temporary_mount, "/dev/mqueue"); |
dc751688 | 464 | (void) mkdir(devmqueue, 0755); |
3164e3cb | 465 | (void) mount("/dev/mqueue", devmqueue, NULL, MS_BIND, NULL); |
2b85f4e1 | 466 | |
63c372cb | 467 | devhugepages = strjoina(temporary_mount, "/dev/hugepages"); |
dc751688 | 468 | (void) mkdir(devhugepages, 0755); |
3164e3cb | 469 | (void) mount("/dev/hugepages", devhugepages, NULL, MS_BIND, NULL); |
2b85f4e1 | 470 | |
63c372cb | 471 | devlog = strjoina(temporary_mount, "/dev/log"); |
3164e3cb | 472 | (void) symlink("/run/systemd/journal/dev-log", devlog); |
82d25240 | 473 | |
7f112f50 | 474 | NULSTR_FOREACH(d, devnodes) { |
2b85f4e1 LP |
475 | _cleanup_free_ char *dn = NULL; |
476 | struct stat st; | |
477 | ||
478 | r = stat(d, &st); | |
7f112f50 | 479 | if (r < 0) { |
2b85f4e1 LP |
480 | |
481 | if (errno == ENOENT) | |
482 | continue; | |
483 | ||
484 | r = -errno; | |
485 | goto fail; | |
7f112f50 LP |
486 | } |
487 | ||
2b85f4e1 LP |
488 | if (!S_ISBLK(st.st_mode) && |
489 | !S_ISCHR(st.st_mode)) { | |
490 | r = -EINVAL; | |
491 | goto fail; | |
492 | } | |
493 | ||
494 | if (st.st_rdev == 0) | |
495 | continue; | |
496 | ||
497 | dn = strappend(temporary_mount, d); | |
498 | if (!dn) { | |
499 | r = -ENOMEM; | |
500 | goto fail; | |
501 | } | |
502 | ||
ecabcf8b | 503 | mac_selinux_create_file_prepare(d, st.st_mode); |
2b85f4e1 | 504 | r = mknod(dn, st.st_mode, st.st_rdev); |
ecabcf8b | 505 | mac_selinux_create_file_clear(); |
dd078a1e | 506 | |
2b85f4e1 LP |
507 | if (r < 0) { |
508 | r = -errno; | |
509 | goto fail; | |
510 | } | |
7f112f50 LP |
511 | } |
512 | ||
03cfe0d5 | 513 | dev_setup(temporary_mount, UID_INVALID, GID_INVALID); |
7f112f50 | 514 | |
ee818b89 AC |
515 | /* Create the /dev directory if missing. It is more likely to be |
516 | * missing when the service is started with RootDirectory. This is | |
517 | * consistent with mount units creating the mount points when missing. | |
518 | */ | |
519 | (void) mkdir_p_label(m->path, 0755); | |
520 | ||
9e5f8252 | 521 | /* Unmount everything in old /dev */ |
522 | umount_recursive(m->path, 0); | |
ee818b89 | 523 | if (mount(dev, m->path, NULL, MS_MOVE, NULL) < 0) { |
2b85f4e1 LP |
524 | r = -errno; |
525 | goto fail; | |
526 | } | |
7f112f50 | 527 | |
2b85f4e1 LP |
528 | rmdir(dev); |
529 | rmdir(temporary_mount); | |
7f112f50 | 530 | |
2b85f4e1 | 531 | return 0; |
7f112f50 | 532 | |
2b85f4e1 LP |
533 | fail: |
534 | if (devpts) | |
535 | umount(devpts); | |
7f112f50 | 536 | |
2b85f4e1 LP |
537 | if (devshm) |
538 | umount(devshm); | |
7f112f50 | 539 | |
2b85f4e1 LP |
540 | if (devhugepages) |
541 | umount(devhugepages); | |
7f112f50 | 542 | |
2b85f4e1 LP |
543 | if (devmqueue) |
544 | umount(devmqueue); | |
7f112f50 | 545 | |
d267c5aa ZJS |
546 | umount(dev); |
547 | rmdir(dev); | |
2b85f4e1 | 548 | rmdir(temporary_mount); |
7f112f50 | 549 | |
2b85f4e1 | 550 | return r; |
7f112f50 LP |
551 | } |
552 | ||
ac0930c8 | 553 | static int apply_mount( |
c17ec25e | 554 | BindMount *m, |
ac0930c8 | 555 | const char *tmp_dir, |
c17ec25e | 556 | const char *var_tmp_dir) { |
ac0930c8 | 557 | |
15ae422b | 558 | const char *what; |
15ae422b | 559 | int r; |
15ae422b | 560 | |
c17ec25e | 561 | assert(m); |
15ae422b | 562 | |
fe3c2583 LP |
563 | log_debug("Applying namespace mount on %s", m->path); |
564 | ||
c17ec25e | 565 | switch (m->mode) { |
15ae422b | 566 | |
160cfdbe LP |
567 | case INACCESSIBLE: { |
568 | struct stat target; | |
6d313367 LP |
569 | |
570 | /* First, get rid of everything that is below if there | |
571 | * is anything... Then, overmount it with an | |
c4b41707 | 572 | * inaccessible path. */ |
fe3c2583 | 573 | (void) umount_recursive(m->path, 0); |
6d313367 | 574 | |
d944dc95 | 575 | if (lstat(m->path, &target) < 0) |
160cfdbe | 576 | return log_debug_errno(errno, "Failed to lstat() %s to determine what to mount over it: %m", m->path); |
15ae422b | 577 | |
c4b41707 | 578 | what = mode_to_inaccessible_node(target.st_mode); |
5fd7cf6f LP |
579 | if (!what) { |
580 | log_debug("File type not supported for inaccessible mounts. Note that symlinks are not allowed"); | |
c4b41707 AP |
581 | return -ELOOP; |
582 | } | |
583 | break; | |
160cfdbe | 584 | } |
fe3c2583 | 585 | |
15ae422b | 586 | case READONLY: |
15ae422b | 587 | case READWRITE: |
6b7c9f8b LP |
588 | |
589 | r = path_is_mount_point(m->path, 0); | |
d944dc95 | 590 | if (r < 0) |
6b7c9f8b | 591 | return log_debug_errno(r, "Failed to determine whether %s is already a mount point: %m", m->path); |
6b7c9f8b LP |
592 | if (r > 0) /* Nothing to do here, it is already a mount. We just later toggle the MS_RDONLY bit for the mount point if needed. */ |
593 | return 0; | |
594 | ||
595 | /* This isn't a mount point yet, let's make it one. */ | |
596 | what = m->path; | |
597 | break; | |
15ae422b | 598 | |
ac0930c8 LP |
599 | case PRIVATE_TMP: |
600 | what = tmp_dir; | |
601 | break; | |
602 | ||
603 | case PRIVATE_VAR_TMP: | |
604 | what = var_tmp_dir; | |
15ae422b | 605 | break; |
e364ad06 | 606 | |
d6797c92 LP |
607 | case PRIVATE_DEV: |
608 | return mount_dev(m); | |
609 | ||
e364ad06 LP |
610 | default: |
611 | assert_not_reached("Unknown mode"); | |
15ae422b LP |
612 | } |
613 | ||
ac0930c8 | 614 | assert(what); |
15ae422b | 615 | |
d944dc95 | 616 | if (mount(what, m->path, NULL, MS_BIND|MS_REC, NULL) < 0) |
5fd7cf6f | 617 | return log_debug_errno(errno, "Failed to mount %s to %s: %m", what, m->path); |
6b7c9f8b LP |
618 | |
619 | log_debug("Successfully mounted %s to %s", what, m->path); | |
620 | return 0; | |
ac0930c8 | 621 | } |
15ae422b | 622 | |
6b7c9f8b LP |
623 | static int make_read_only(BindMount *m, char **blacklist) { |
624 | int r = 0; | |
15ae422b | 625 | |
c17ec25e | 626 | assert(m); |
ac0930c8 | 627 | |
d6797c92 | 628 | if (IN_SET(m->mode, INACCESSIBLE, READONLY)) |
6b7c9f8b LP |
629 | r = bind_remount_recursive(m->path, true, blacklist); |
630 | else if (m->mode == PRIVATE_DEV) { /* Can be readonly but the submounts can't*/ | |
631 | if (mount(NULL, m->path, NULL, MS_REMOUNT|DEV_MOUNT_OPTIONS|MS_RDONLY, NULL) < 0) | |
632 | r = -errno; | |
737ba3c8 | 633 | } else |
6b7c9f8b LP |
634 | return 0; |
635 | ||
636 | /* Not that we only turn on the MS_RDONLY flag here, we never turn it off. Something that was marked read-only | |
637 | * already stays this way. This improves compatibility with container managers, where we won't attempt to undo | |
638 | * read-only mounts already applied. */ | |
ac0930c8 | 639 | |
d6797c92 | 640 | return r; |
15ae422b LP |
641 | } |
642 | ||
d944dc95 LP |
643 | static int chase_all_symlinks(const char *root_directory, BindMount *m, unsigned *n) { |
644 | BindMount *f, *t; | |
645 | int r; | |
646 | ||
647 | assert(m); | |
648 | assert(n); | |
649 | ||
650 | /* Since mount() will always follow symlinks and we need to take the different root directory into account we | |
651 | * chase the symlinks on our own first. This call wil do so for all entries and remove all entries where we | |
652 | * can't resolve the path, and which have been marked for such removal. */ | |
653 | ||
654 | for (f = m, t = m; f < m+*n; f++) { | |
655 | ||
656 | r = chase_symlinks(f->path, root_directory, &f->chased); | |
657 | if (r == -ENOENT && f->ignore) /* Doesn't exist? Then remove it! */ | |
658 | continue; | |
659 | if (r < 0) | |
660 | return log_debug_errno(r, "Failed to chase symlinks for %s: %m", f->path); | |
661 | ||
662 | if (path_equal(f->path, f->chased)) | |
663 | f->chased = mfree(f->chased); | |
664 | else { | |
665 | log_debug("Chased %s → %s", f->path, f->chased); | |
666 | f->path = f->chased; | |
667 | } | |
668 | ||
669 | *t = *f; | |
670 | t++; | |
671 | } | |
672 | ||
673 | *n = t - m; | |
674 | return 0; | |
675 | } | |
676 | ||
2652c6c1 | 677 | static unsigned namespace_calculate_mounts( |
c575770b | 678 | const NameSpaceInfo *ns_info, |
2652c6c1 DH |
679 | char** read_write_paths, |
680 | char** read_only_paths, | |
681 | char** inaccessible_paths, | |
682 | const char* tmp_dir, | |
683 | const char* var_tmp_dir, | |
2652c6c1 DH |
684 | ProtectHome protect_home, |
685 | ProtectSystem protect_system) { | |
686 | ||
b6c432ca | 687 | unsigned protect_home_cnt; |
f471b2af DH |
688 | unsigned protect_system_cnt = |
689 | (protect_system == PROTECT_SYSTEM_STRICT ? | |
690 | ELEMENTSOF(protect_system_strict_table) : | |
691 | ((protect_system == PROTECT_SYSTEM_FULL) ? | |
692 | ELEMENTSOF(protect_system_full_table) : | |
693 | ((protect_system == PROTECT_SYSTEM_YES) ? | |
694 | ELEMENTSOF(protect_system_yes_table) : 0))); | |
695 | ||
b6c432ca DH |
696 | protect_home_cnt = |
697 | (protect_home == PROTECT_HOME_YES ? | |
698 | ELEMENTSOF(protect_home_yes_table) : | |
699 | ((protect_home == PROTECT_HOME_READ_ONLY) ? | |
700 | ELEMENTSOF(protect_home_read_only_table) : 0)); | |
701 | ||
2652c6c1 DH |
702 | return !!tmp_dir + !!var_tmp_dir + |
703 | strv_length(read_write_paths) + | |
704 | strv_length(read_only_paths) + | |
705 | strv_length(inaccessible_paths) + | |
c575770b DH |
706 | ns_info->private_dev + |
707 | (ns_info->protect_kernel_tunables ? ELEMENTSOF(protect_kernel_tunables_table) : 0) + | |
708 | (ns_info->protect_control_groups ? 1 : 0) + | |
709 | (ns_info->protect_kernel_modules ? ELEMENTSOF(protect_kernel_modules_table) : 0) + | |
b6c432ca | 710 | protect_home_cnt + protect_system_cnt; |
2652c6c1 DH |
711 | } |
712 | ||
613b411c | 713 | int setup_namespace( |
ee818b89 | 714 | const char* root_directory, |
c575770b | 715 | const NameSpaceInfo *ns_info, |
2a624c36 AP |
716 | char** read_write_paths, |
717 | char** read_only_paths, | |
718 | char** inaccessible_paths, | |
a004cb4c LP |
719 | const char* tmp_dir, |
720 | const char* var_tmp_dir, | |
1b8689f9 LP |
721 | ProtectHome protect_home, |
722 | ProtectSystem protect_system, | |
e6547662 | 723 | unsigned long mount_flags) { |
15ae422b | 724 | |
7ff7394d | 725 | BindMount *m, *mounts = NULL; |
d944dc95 | 726 | bool make_slave = false; |
613b411c | 727 | unsigned n; |
c17ec25e | 728 | int r = 0; |
15ae422b | 729 | |
613b411c | 730 | if (mount_flags == 0) |
c17ec25e | 731 | mount_flags = MS_SHARED; |
ac0930c8 | 732 | |
c575770b DH |
733 | n = namespace_calculate_mounts(ns_info, |
734 | read_write_paths, | |
2652c6c1 DH |
735 | read_only_paths, |
736 | inaccessible_paths, | |
737 | tmp_dir, var_tmp_dir, | |
c575770b | 738 | protect_home, protect_system); |
613b411c | 739 | |
2652c6c1 | 740 | /* Set mount slave mode */ |
d944dc95 LP |
741 | if (root_directory || n > 0) |
742 | make_slave = true; | |
743 | ||
613b411c | 744 | if (n > 0) { |
002b2268 | 745 | m = mounts = (BindMount *) alloca0(n * sizeof(BindMount)); |
2a624c36 | 746 | r = append_mounts(&m, read_write_paths, READWRITE); |
613b411c LP |
747 | if (r < 0) |
748 | return r; | |
749 | ||
2a624c36 | 750 | r = append_mounts(&m, read_only_paths, READONLY); |
613b411c LP |
751 | if (r < 0) |
752 | return r; | |
753 | ||
2a624c36 | 754 | r = append_mounts(&m, inaccessible_paths, INACCESSIBLE); |
613b411c | 755 | if (r < 0) |
7ff7394d ZJS |
756 | return r; |
757 | ||
613b411c | 758 | if (tmp_dir) { |
ee818b89 | 759 | m->path = prefix_roota(root_directory, "/tmp"); |
7ff7394d ZJS |
760 | m->mode = PRIVATE_TMP; |
761 | m++; | |
613b411c | 762 | } |
7ff7394d | 763 | |
613b411c | 764 | if (var_tmp_dir) { |
ee818b89 | 765 | m->path = prefix_roota(root_directory, "/var/tmp"); |
7ff7394d ZJS |
766 | m->mode = PRIVATE_VAR_TMP; |
767 | m++; | |
768 | } | |
ac0930c8 | 769 | |
c575770b | 770 | if (ns_info->private_dev) { |
ee818b89 | 771 | m->path = prefix_roota(root_directory, "/dev"); |
7f112f50 LP |
772 | m->mode = PRIVATE_DEV; |
773 | m++; | |
774 | } | |
775 | ||
c575770b DH |
776 | if (ns_info->protect_kernel_tunables) { |
777 | r = append_protect_kernel_tunables(&m, root_directory); | |
778 | if (r < 0) | |
779 | return r; | |
780 | } | |
781 | ||
782 | if (ns_info->protect_kernel_modules) { | |
783 | r = append_protect_kernel_modules(&m, root_directory); | |
784 | if (r < 0) | |
785 | return r; | |
786 | } | |
59eeb84b | 787 | |
c575770b | 788 | if (ns_info->protect_control_groups) { |
59eeb84b | 789 | m->path = prefix_roota(root_directory, "/sys/fs/cgroup"); |
11a30cec | 790 | m->mode = READONLY; |
59eeb84b LP |
791 | m++; |
792 | } | |
793 | ||
b6c432ca DH |
794 | r = append_protect_home(&m, root_directory, protect_home); |
795 | if (r < 0) | |
796 | return r; | |
417116f2 | 797 | |
f471b2af DH |
798 | r = append_protect_system(&m, root_directory, protect_system); |
799 | if (r < 0) | |
800 | return r; | |
417116f2 | 801 | |
7ff7394d | 802 | assert(mounts + n == m); |
ac0930c8 | 803 | |
d944dc95 LP |
804 | /* Resolve symlinks manually first, as mount() will always follow them relative to the host's |
805 | * root. Moreover we want to suppress duplicates based on the resolved paths. This of course is a bit | |
806 | * racy. */ | |
807 | r = chase_all_symlinks(root_directory, mounts, &n); | |
808 | if (r < 0) | |
809 | goto finish; | |
810 | ||
7ff7394d | 811 | qsort(mounts, n, sizeof(BindMount), mount_path_compare); |
fe3c2583 | 812 | |
7ff7394d | 813 | drop_duplicates(mounts, &n); |
cd2902c9 | 814 | drop_outside_root(root_directory, mounts, &n); |
fe3c2583 | 815 | drop_inaccessible(mounts, &n); |
7648a565 | 816 | drop_nop(mounts, &n); |
15ae422b LP |
817 | } |
818 | ||
d944dc95 LP |
819 | if (unshare(CLONE_NEWNS) < 0) { |
820 | r = -errno; | |
821 | goto finish; | |
822 | } | |
1e4e94c8 | 823 | |
d944dc95 | 824 | if (make_slave) { |
c2c13f2d LP |
825 | /* Remount / as SLAVE so that nothing now mounted in the namespace |
826 | shows up in the parent */ | |
d944dc95 LP |
827 | if (mount(NULL, "/", NULL, MS_SLAVE|MS_REC, NULL) < 0) { |
828 | r = -errno; | |
829 | goto finish; | |
830 | } | |
ee818b89 AC |
831 | } |
832 | ||
833 | if (root_directory) { | |
8f1ad200 LP |
834 | /* Turn directory into bind mount, if it isn't one yet */ |
835 | r = path_is_mount_point(root_directory, AT_SYMLINK_FOLLOW); | |
836 | if (r < 0) | |
d944dc95 | 837 | goto finish; |
8f1ad200 LP |
838 | if (r == 0) { |
839 | if (mount(root_directory, root_directory, NULL, MS_BIND|MS_REC, NULL) < 0) { | |
840 | r = -errno; | |
841 | goto finish; | |
842 | } | |
d944dc95 | 843 | } |
ee818b89 | 844 | } |
c2c13f2d | 845 | |
ee818b89 | 846 | if (n > 0) { |
6b7c9f8b LP |
847 | char **blacklist; |
848 | unsigned j; | |
849 | ||
850 | /* First round, add in all special mounts we need */ | |
c2c13f2d LP |
851 | for (m = mounts; m < mounts + n; ++m) { |
852 | r = apply_mount(m, tmp_dir, var_tmp_dir); | |
853 | if (r < 0) | |
d944dc95 | 854 | goto finish; |
c2c13f2d | 855 | } |
15ae422b | 856 | |
6b7c9f8b LP |
857 | /* Create a blacklist we can pass to bind_mount_recursive() */ |
858 | blacklist = newa(char*, n+1); | |
859 | for (j = 0; j < n; j++) | |
860 | blacklist[j] = (char*) mounts[j].path; | |
861 | blacklist[j] = NULL; | |
862 | ||
863 | /* Second round, flip the ro bits if necessary. */ | |
c2c13f2d | 864 | for (m = mounts; m < mounts + n; ++m) { |
6b7c9f8b | 865 | r = make_read_only(m, blacklist); |
c2c13f2d | 866 | if (r < 0) |
d944dc95 | 867 | goto finish; |
c2c13f2d | 868 | } |
15ae422b LP |
869 | } |
870 | ||
ee818b89 AC |
871 | if (root_directory) { |
872 | /* MS_MOVE does not work on MS_SHARED so the remount MS_SHARED will be done later */ | |
873 | r = mount_move_root(root_directory); | |
d944dc95 LP |
874 | if (r < 0) |
875 | goto finish; | |
ee818b89 AC |
876 | } |
877 | ||
c2c13f2d LP |
878 | /* Remount / as the desired mode. Not that this will not |
879 | * reestablish propagation from our side to the host, since | |
880 | * what's disconnected is disconnected. */ | |
d944dc95 LP |
881 | if (mount(NULL, "/", NULL, mount_flags | MS_REC, NULL) < 0) { |
882 | r = -errno; | |
883 | goto finish; | |
884 | } | |
15ae422b | 885 | |
d944dc95 | 886 | r = 0; |
15ae422b | 887 | |
d944dc95 LP |
888 | finish: |
889 | for (m = mounts; m < mounts + n; m++) | |
890 | free(m->chased); | |
613b411c LP |
891 | |
892 | return r; | |
893 | } | |
894 | ||
895 | static int setup_one_tmp_dir(const char *id, const char *prefix, char **path) { | |
896 | _cleanup_free_ char *x = NULL; | |
6b46ea73 LP |
897 | char bid[SD_ID128_STRING_MAX]; |
898 | sd_id128_t boot_id; | |
899 | int r; | |
613b411c LP |
900 | |
901 | assert(id); | |
902 | assert(prefix); | |
903 | assert(path); | |
904 | ||
6b46ea73 LP |
905 | /* We include the boot id in the directory so that after a |
906 | * reboot we can easily identify obsolete directories. */ | |
907 | ||
908 | r = sd_id128_get_boot(&boot_id); | |
909 | if (r < 0) | |
910 | return r; | |
911 | ||
912 | x = strjoin(prefix, "/systemd-private-", sd_id128_to_string(boot_id, bid), "-", id, "-XXXXXX", NULL); | |
613b411c LP |
913 | if (!x) |
914 | return -ENOMEM; | |
915 | ||
916 | RUN_WITH_UMASK(0077) | |
917 | if (!mkdtemp(x)) | |
918 | return -errno; | |
919 | ||
920 | RUN_WITH_UMASK(0000) { | |
921 | char *y; | |
922 | ||
63c372cb | 923 | y = strjoina(x, "/tmp"); |
613b411c LP |
924 | |
925 | if (mkdir(y, 0777 | S_ISVTX) < 0) | |
926 | return -errno; | |
c17ec25e | 927 | } |
15ae422b | 928 | |
613b411c LP |
929 | *path = x; |
930 | x = NULL; | |
931 | ||
932 | return 0; | |
933 | } | |
934 | ||
935 | int setup_tmp_dirs(const char *id, char **tmp_dir, char **var_tmp_dir) { | |
936 | char *a, *b; | |
937 | int r; | |
938 | ||
939 | assert(id); | |
940 | assert(tmp_dir); | |
941 | assert(var_tmp_dir); | |
942 | ||
943 | r = setup_one_tmp_dir(id, "/tmp", &a); | |
944 | if (r < 0) | |
945 | return r; | |
946 | ||
947 | r = setup_one_tmp_dir(id, "/var/tmp", &b); | |
948 | if (r < 0) { | |
949 | char *t; | |
950 | ||
63c372cb | 951 | t = strjoina(a, "/tmp"); |
613b411c LP |
952 | rmdir(t); |
953 | rmdir(a); | |
954 | ||
955 | free(a); | |
956 | return r; | |
957 | } | |
958 | ||
959 | *tmp_dir = a; | |
960 | *var_tmp_dir = b; | |
961 | ||
962 | return 0; | |
963 | } | |
964 | ||
965 | int setup_netns(int netns_storage_socket[2]) { | |
966 | _cleanup_close_ int netns = -1; | |
3ee897d6 | 967 | int r, q; |
613b411c LP |
968 | |
969 | assert(netns_storage_socket); | |
970 | assert(netns_storage_socket[0] >= 0); | |
971 | assert(netns_storage_socket[1] >= 0); | |
972 | ||
973 | /* We use the passed socketpair as a storage buffer for our | |
76cd584b LP |
974 | * namespace reference fd. Whatever process runs this first |
975 | * shall create a new namespace, all others should just join | |
976 | * it. To serialize that we use a file lock on the socket | |
977 | * pair. | |
613b411c LP |
978 | * |
979 | * It's a bit crazy, but hey, works great! */ | |
980 | ||
981 | if (lockf(netns_storage_socket[0], F_LOCK, 0) < 0) | |
982 | return -errno; | |
983 | ||
3ee897d6 LP |
984 | netns = receive_one_fd(netns_storage_socket[0], MSG_DONTWAIT); |
985 | if (netns == -EAGAIN) { | |
613b411c LP |
986 | /* Nothing stored yet, so let's create a new namespace */ |
987 | ||
988 | if (unshare(CLONE_NEWNET) < 0) { | |
989 | r = -errno; | |
990 | goto fail; | |
991 | } | |
992 | ||
993 | loopback_setup(); | |
994 | ||
995 | netns = open("/proc/self/ns/net", O_RDONLY|O_CLOEXEC|O_NOCTTY); | |
996 | if (netns < 0) { | |
997 | r = -errno; | |
998 | goto fail; | |
999 | } | |
1000 | ||
1001 | r = 1; | |
613b411c | 1002 | |
3ee897d6 LP |
1003 | } else if (netns < 0) { |
1004 | r = netns; | |
1005 | goto fail; | |
613b411c | 1006 | |
3ee897d6 LP |
1007 | } else { |
1008 | /* Yay, found something, so let's join the namespace */ | |
613b411c LP |
1009 | if (setns(netns, CLONE_NEWNET) < 0) { |
1010 | r = -errno; | |
1011 | goto fail; | |
1012 | } | |
1013 | ||
1014 | r = 0; | |
1015 | } | |
1016 | ||
3ee897d6 LP |
1017 | q = send_one_fd(netns_storage_socket[1], netns, MSG_DONTWAIT); |
1018 | if (q < 0) { | |
1019 | r = q; | |
613b411c LP |
1020 | goto fail; |
1021 | } | |
1022 | ||
1023 | fail: | |
fe048ce5 | 1024 | (void) lockf(netns_storage_socket[0], F_ULOCK, 0); |
15ae422b LP |
1025 | return r; |
1026 | } | |
417116f2 | 1027 | |
1b8689f9 LP |
1028 | static const char *const protect_home_table[_PROTECT_HOME_MAX] = { |
1029 | [PROTECT_HOME_NO] = "no", | |
1030 | [PROTECT_HOME_YES] = "yes", | |
1031 | [PROTECT_HOME_READ_ONLY] = "read-only", | |
417116f2 LP |
1032 | }; |
1033 | ||
1b8689f9 LP |
1034 | DEFINE_STRING_TABLE_LOOKUP(protect_home, ProtectHome); |
1035 | ||
1036 | static const char *const protect_system_table[_PROTECT_SYSTEM_MAX] = { | |
1037 | [PROTECT_SYSTEM_NO] = "no", | |
1038 | [PROTECT_SYSTEM_YES] = "yes", | |
1039 | [PROTECT_SYSTEM_FULL] = "full", | |
3f815163 | 1040 | [PROTECT_SYSTEM_STRICT] = "strict", |
1b8689f9 LP |
1041 | }; |
1042 | ||
1043 | DEFINE_STRING_TABLE_LOOKUP(protect_system, ProtectSystem); |