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Commit | Line | Data |
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53e1b683 | 1 | /* SPDX-License-Identifier: LGPL-2.1+ */ |
e83bebef | 2 | |
4f5dd394 | 3 | #include <sys/mount.h> |
07630cea | 4 | #include <linux/magic.h> |
e83bebef | 5 | |
b5efdb8a | 6 | #include "alloc-util.h" |
4f5dd394 | 7 | #include "escape.h" |
0996ef00 | 8 | #include "fd-util.h" |
ca78ad1d | 9 | #include "format-util.h" |
f4f15635 | 10 | #include "fs-util.h" |
e83bebef | 11 | #include "label.h" |
4f5dd394 | 12 | #include "mkdir.h" |
4349cd7c | 13 | #include "mount-util.h" |
049af8ad | 14 | #include "mountpoint-util.h" |
6bedfcbb LP |
15 | #include "nspawn-mount.h" |
16 | #include "parse-util.h" | |
4f5dd394 LP |
17 | #include "path-util.h" |
18 | #include "rm-rf.h" | |
e83bebef | 19 | #include "set.h" |
760877e9 | 20 | #include "sort-util.h" |
8fcde012 | 21 | #include "stat-util.h" |
07630cea | 22 | #include "string-util.h" |
4f5dd394 | 23 | #include "strv.h" |
e4de7287 | 24 | #include "tmpfile-util.h" |
ee104e11 | 25 | #include "user-util.h" |
e83bebef | 26 | |
88614c8a | 27 | CustomMount* custom_mount_add(CustomMount **l, size_t *n, CustomMountType t) { |
e83bebef LP |
28 | CustomMount *c, *ret; |
29 | ||
30 | assert(l); | |
31 | assert(n); | |
32 | assert(t >= 0); | |
33 | assert(t < _CUSTOM_MOUNT_TYPE_MAX); | |
34 | ||
aa484f35 | 35 | c = reallocarray(*l, *n + 1, sizeof(CustomMount)); |
e83bebef LP |
36 | if (!c) |
37 | return NULL; | |
38 | ||
39 | *l = c; | |
40 | ret = *l + *n; | |
41 | (*n)++; | |
42 | ||
43 | *ret = (CustomMount) { .type = t }; | |
44 | ||
45 | return ret; | |
46 | } | |
47 | ||
88614c8a LP |
48 | void custom_mount_free_all(CustomMount *l, size_t n) { |
49 | size_t i; | |
e83bebef LP |
50 | |
51 | for (i = 0; i < n; i++) { | |
52 | CustomMount *m = l + i; | |
53 | ||
54 | free(m->source); | |
55 | free(m->destination); | |
56 | free(m->options); | |
57 | ||
58 | if (m->work_dir) { | |
59 | (void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL); | |
60 | free(m->work_dir); | |
61 | } | |
62 | ||
c7a4890c LP |
63 | if (m->rm_rf_tmpdir) { |
64 | (void) rm_rf(m->rm_rf_tmpdir, REMOVE_ROOT|REMOVE_PHYSICAL); | |
65 | free(m->rm_rf_tmpdir); | |
66 | } | |
67 | ||
e83bebef | 68 | strv_free(m->lower); |
de40a303 | 69 | free(m->type_argument); |
e83bebef LP |
70 | } |
71 | ||
72 | free(l); | |
73 | } | |
74 | ||
93bab288 | 75 | static int custom_mount_compare(const CustomMount *a, const CustomMount *b) { |
e83bebef LP |
76 | int r; |
77 | ||
93bab288 | 78 | r = path_compare(a->destination, b->destination); |
e83bebef LP |
79 | if (r != 0) |
80 | return r; | |
81 | ||
93bab288 | 82 | return CMP(a->type, b->type); |
e83bebef LP |
83 | } |
84 | ||
86c0dd4a LP |
85 | static bool source_path_is_valid(const char *p) { |
86 | assert(p); | |
87 | ||
88 | if (*p == '+') | |
89 | p++; | |
90 | ||
91 | return path_is_absolute(p); | |
92 | } | |
93 | ||
94 | static char *resolve_source_path(const char *dest, const char *source) { | |
95 | ||
96 | if (!source) | |
97 | return NULL; | |
98 | ||
99 | if (source[0] == '+') | |
100 | return prefix_root(dest, source + 1); | |
101 | ||
102 | return strdup(source); | |
103 | } | |
104 | ||
88614c8a LP |
105 | int custom_mount_prepare_all(const char *dest, CustomMount *l, size_t n) { |
106 | size_t i; | |
86c0dd4a LP |
107 | int r; |
108 | ||
109 | /* Prepare all custom mounts. This will make source we know all temporary directories. This is called in the | |
110 | * parent process, so that we know the temporary directories to remove on exit before we fork off the | |
111 | * children. */ | |
112 | ||
113 | assert(l || n == 0); | |
114 | ||
115 | /* Order the custom mounts, and make sure we have a working directory */ | |
93bab288 | 116 | typesafe_qsort(l, n, custom_mount_compare); |
86c0dd4a LP |
117 | |
118 | for (i = 0; i < n; i++) { | |
119 | CustomMount *m = l + i; | |
120 | ||
de40a303 LP |
121 | /* /proc we mount in the inner child, i.e. when we acquired CLONE_NEWPID. All other mounts we mount |
122 | * already in the outer child, so that the mounts are already established before CLONE_NEWPID and in | |
123 | * particular CLONE_NEWUSER. This also means any custom mounts below /proc also need to be mounted in | |
124 | * the inner child, not the outer one. Determine this here. */ | |
125 | m->in_userns = path_startswith(m->destination, "/proc"); | |
86c0dd4a | 126 | |
de40a303 LP |
127 | if (m->type == CUSTOM_MOUNT_BIND) { |
128 | if (m->source) { | |
129 | char *s; | |
86c0dd4a | 130 | |
de40a303 LP |
131 | s = resolve_source_path(dest, m->source); |
132 | if (!s) | |
133 | return log_oom(); | |
c7a4890c | 134 | |
de40a303 LP |
135 | free_and_replace(m->source, s); |
136 | } else { | |
137 | /* No source specified? In that case, use a throw-away temporary directory in /var/tmp */ | |
c7a4890c | 138 | |
de40a303 LP |
139 | m->rm_rf_tmpdir = strdup("/var/tmp/nspawn-temp-XXXXXX"); |
140 | if (!m->rm_rf_tmpdir) | |
141 | return log_oom(); | |
c7a4890c | 142 | |
de40a303 LP |
143 | if (!mkdtemp(m->rm_rf_tmpdir)) { |
144 | m->rm_rf_tmpdir = mfree(m->rm_rf_tmpdir); | |
145 | return log_error_errno(errno, "Failed to acquire temporary directory: %m"); | |
146 | } | |
147 | ||
148 | m->source = strjoin(m->rm_rf_tmpdir, "/src"); | |
149 | if (!m->source) | |
150 | return log_oom(); | |
c7a4890c | 151 | |
de40a303 LP |
152 | if (mkdir(m->source, 0755) < 0) |
153 | return log_error_errno(errno, "Failed to create %s: %m", m->source); | |
154 | } | |
86c0dd4a LP |
155 | } |
156 | ||
157 | if (m->type == CUSTOM_MOUNT_OVERLAY) { | |
158 | char **j; | |
159 | ||
160 | STRV_FOREACH(j, m->lower) { | |
161 | char *s; | |
162 | ||
163 | s = resolve_source_path(dest, *j); | |
164 | if (!s) | |
165 | return log_oom(); | |
166 | ||
10af01a5 | 167 | free_and_replace(*j, s); |
86c0dd4a LP |
168 | } |
169 | ||
170 | if (m->work_dir) { | |
171 | char *s; | |
172 | ||
173 | s = resolve_source_path(dest, m->work_dir); | |
174 | if (!s) | |
175 | return log_oom(); | |
176 | ||
10af01a5 | 177 | free_and_replace(m->work_dir, s); |
86c0dd4a LP |
178 | } else { |
179 | assert(m->source); | |
180 | ||
181 | r = tempfn_random(m->source, NULL, &m->work_dir); | |
182 | if (r < 0) | |
183 | return log_error_errno(r, "Failed to acquire working directory: %m"); | |
184 | } | |
185 | ||
186 | (void) mkdir_label(m->work_dir, 0700); | |
187 | } | |
188 | } | |
189 | ||
190 | return 0; | |
191 | } | |
192 | ||
88614c8a | 193 | int bind_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
e83bebef LP |
194 | _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL; |
195 | const char *p = s; | |
196 | CustomMount *m; | |
197 | int r; | |
198 | ||
199 | assert(l); | |
200 | assert(n); | |
201 | ||
202 | r = extract_many_words(&p, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); | |
203 | if (r < 0) | |
204 | return r; | |
205 | if (r == 0) | |
206 | return -EINVAL; | |
e83bebef | 207 | if (r == 1) { |
86c0dd4a | 208 | destination = strdup(source[0] == '+' ? source+1 : source); |
e83bebef LP |
209 | if (!destination) |
210 | return -ENOMEM; | |
211 | } | |
e83bebef LP |
212 | if (r == 2 && !isempty(p)) { |
213 | opts = strdup(p); | |
214 | if (!opts) | |
215 | return -ENOMEM; | |
216 | } | |
217 | ||
c7a4890c | 218 | if (isempty(source)) |
0e636bf5 | 219 | source = mfree(source); |
c7a4890c | 220 | else if (!source_path_is_valid(source)) |
e83bebef | 221 | return -EINVAL; |
c7a4890c | 222 | |
e83bebef LP |
223 | if (!path_is_absolute(destination)) |
224 | return -EINVAL; | |
0646d3c3 LP |
225 | if (empty_or_root(destination)) |
226 | return -EINVAL; | |
e83bebef LP |
227 | |
228 | m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); | |
229 | if (!m) | |
48cbe5f8 | 230 | return -ENOMEM; |
e83bebef | 231 | |
0e636bf5 ZJS |
232 | m->source = TAKE_PTR(source); |
233 | m->destination = TAKE_PTR(destination); | |
e83bebef | 234 | m->read_only = read_only; |
0e636bf5 | 235 | m->options = TAKE_PTR(opts); |
de40a303 | 236 | |
e83bebef LP |
237 | return 0; |
238 | } | |
239 | ||
88614c8a | 240 | int tmpfs_mount_parse(CustomMount **l, size_t *n, const char *s) { |
e83bebef LP |
241 | _cleanup_free_ char *path = NULL, *opts = NULL; |
242 | const char *p = s; | |
243 | CustomMount *m; | |
244 | int r; | |
245 | ||
246 | assert(l); | |
247 | assert(n); | |
248 | assert(s); | |
249 | ||
250 | r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS); | |
251 | if (r < 0) | |
252 | return r; | |
253 | if (r == 0) | |
254 | return -EINVAL; | |
255 | ||
256 | if (isempty(p)) | |
257 | opts = strdup("mode=0755"); | |
258 | else | |
259 | opts = strdup(p); | |
260 | if (!opts) | |
261 | return -ENOMEM; | |
262 | ||
263 | if (!path_is_absolute(path)) | |
264 | return -EINVAL; | |
0646d3c3 LP |
265 | if (empty_or_root(path)) |
266 | return -EINVAL; | |
e83bebef LP |
267 | |
268 | m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS); | |
269 | if (!m) | |
270 | return -ENOMEM; | |
271 | ||
1cc6c93a YW |
272 | m->destination = TAKE_PTR(path); |
273 | m->options = TAKE_PTR(opts); | |
e83bebef | 274 | |
e83bebef LP |
275 | return 0; |
276 | } | |
277 | ||
88614c8a | 278 | int overlay_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
ad85779a LP |
279 | _cleanup_free_ char *upper = NULL, *destination = NULL; |
280 | _cleanup_strv_free_ char **lower = NULL; | |
281 | CustomMount *m; | |
86c0dd4a | 282 | int k; |
ad85779a | 283 | |
86c0dd4a LP |
284 | k = strv_split_extract(&lower, s, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
285 | if (k < 0) | |
286 | return k; | |
ad85779a LP |
287 | if (k < 2) |
288 | return -EADDRNOTAVAIL; | |
289 | if (k == 2) { | |
86c0dd4a LP |
290 | /* If two parameters are specified, the first one is the lower, the second one the upper directory. And |
291 | * we'll also define the destination mount point the same as the upper. */ | |
292 | ||
293 | if (!source_path_is_valid(lower[0]) || | |
294 | !source_path_is_valid(lower[1])) | |
295 | return -EINVAL; | |
296 | ||
ae2a15bc | 297 | upper = TAKE_PTR(lower[1]); |
ad85779a | 298 | |
86c0dd4a | 299 | destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */ |
ad85779a LP |
300 | if (!destination) |
301 | return -ENOMEM; | |
ad85779a | 302 | } else { |
c7a4890c | 303 | char **i; |
86c0dd4a LP |
304 | |
305 | /* If more than two parameters are specified, the last one is the destination, the second to last one | |
306 | * the "upper", and all before that the "lower" directories. */ | |
307 | ||
ad85779a | 308 | destination = lower[k - 1]; |
ae2a15bc | 309 | upper = TAKE_PTR(lower[k - 2]); |
86c0dd4a | 310 | |
c7a4890c LP |
311 | STRV_FOREACH(i, lower) |
312 | if (!source_path_is_valid(*i)) | |
313 | return -EINVAL; | |
314 | ||
315 | /* If the upper directory is unspecified, then let's create it automatically as a throw-away directory | |
316 | * in /var/tmp */ | |
317 | if (isempty(upper)) | |
1d0c1146 | 318 | upper = mfree(upper); |
c7a4890c LP |
319 | else if (!source_path_is_valid(upper)) |
320 | return -EINVAL; | |
321 | ||
86c0dd4a LP |
322 | if (!path_is_absolute(destination)) |
323 | return -EINVAL; | |
ad85779a LP |
324 | } |
325 | ||
0646d3c3 LP |
326 | if (empty_or_root(destination)) |
327 | return -EINVAL; | |
328 | ||
ad85779a LP |
329 | m = custom_mount_add(l, n, CUSTOM_MOUNT_OVERLAY); |
330 | if (!m) | |
331 | return -ENOMEM; | |
332 | ||
1cc6c93a YW |
333 | m->destination = TAKE_PTR(destination); |
334 | m->source = TAKE_PTR(upper); | |
335 | m->lower = TAKE_PTR(lower); | |
ad85779a LP |
336 | m->read_only = read_only; |
337 | ||
ad85779a LP |
338 | return 0; |
339 | } | |
340 | ||
de40a303 LP |
341 | int inaccessible_mount_parse(CustomMount **l, size_t *n, const char *s) { |
342 | _cleanup_free_ char *path = NULL; | |
343 | CustomMount *m; | |
344 | ||
345 | assert(l); | |
346 | assert(n); | |
347 | assert(s); | |
348 | ||
349 | if (!path_is_absolute(s)) | |
350 | return -EINVAL; | |
351 | ||
352 | path = strdup(s); | |
353 | if (!path) | |
354 | return -ENOMEM; | |
355 | ||
356 | m = custom_mount_add(l, n, CUSTOM_MOUNT_INACCESSIBLE); | |
357 | if (!m) | |
358 | return -ENOMEM; | |
359 | ||
360 | m->destination = TAKE_PTR(path); | |
361 | return 0; | |
362 | } | |
363 | ||
04029482 | 364 | int tmpfs_patch_options( |
e83bebef | 365 | const char *options, |
2fa017f1 | 366 | uid_t uid_shift, |
e83bebef LP |
367 | const char *selinux_apifs_context, |
368 | char **ret) { | |
369 | ||
370 | char *buf = NULL; | |
371 | ||
2fa017f1 | 372 | if (uid_shift != UID_INVALID) { |
9aa2169e | 373 | if (asprintf(&buf, "%s%suid=" UID_FMT ",gid=" UID_FMT, |
87e4e28d | 374 | strempty(options), options ? "," : "", |
9aa2169e | 375 | uid_shift, uid_shift) < 0) |
e83bebef LP |
376 | return -ENOMEM; |
377 | ||
378 | options = buf; | |
379 | } | |
380 | ||
349cc4a5 | 381 | #if HAVE_SELINUX |
e83bebef LP |
382 | if (selinux_apifs_context) { |
383 | char *t; | |
384 | ||
87e4e28d | 385 | t = strjoin(strempty(options), options ? "," : "", |
9aa2169e ZJS |
386 | "context=\"", selinux_apifs_context, "\""); |
387 | free(buf); | |
388 | if (!t) | |
e83bebef | 389 | return -ENOMEM; |
e83bebef | 390 | |
e83bebef LP |
391 | buf = t; |
392 | } | |
393 | #endif | |
394 | ||
0996ef00 CB |
395 | if (!buf && options) { |
396 | buf = strdup(options); | |
397 | if (!buf) | |
398 | return -ENOMEM; | |
399 | } | |
e83bebef | 400 | *ret = buf; |
0996ef00 | 401 | |
e83bebef LP |
402 | return !!buf; |
403 | } | |
404 | ||
4f086aab | 405 | int mount_sysfs(const char *dest, MountSettingsMask mount_settings) { |
d8fc6a00 | 406 | const char *full, *top, *x; |
d1678248 | 407 | int r; |
4f086aab | 408 | unsigned long extra_flags = 0; |
d8fc6a00 LP |
409 | |
410 | top = prefix_roota(dest, "/sys"); | |
40fd52f2 | 411 | r = path_is_fs_type(top, SYSFS_MAGIC); |
d1678248 ILG |
412 | if (r < 0) |
413 | return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top); | |
414 | /* /sys might already be mounted as sysfs by the outer child in the | |
415 | * !netns case. In this case, it's all good. Don't touch it because we | |
416 | * don't have the right to do so, see https://github.com/systemd/systemd/issues/1555. | |
417 | */ | |
418 | if (r > 0) | |
419 | return 0; | |
420 | ||
d8fc6a00 LP |
421 | full = prefix_roota(top, "/full"); |
422 | ||
423 | (void) mkdir(full, 0755); | |
424 | ||
4f086aab SU |
425 | if (mount_settings & MOUNT_APPLY_APIVFS_RO) |
426 | extra_flags |= MS_RDONLY; | |
427 | ||
60e76d48 | 428 | r = mount_verbose(LOG_ERR, "sysfs", full, "sysfs", |
4f086aab | 429 | MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL); |
60e76d48 ZJS |
430 | if (r < 0) |
431 | return r; | |
d8fc6a00 LP |
432 | |
433 | FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { | |
434 | _cleanup_free_ char *from = NULL, *to = NULL; | |
435 | ||
436 | from = prefix_root(full, x); | |
437 | if (!from) | |
438 | return log_oom(); | |
439 | ||
440 | to = prefix_root(top, x); | |
441 | if (!to) | |
442 | return log_oom(); | |
443 | ||
444 | (void) mkdir(to, 0755); | |
445 | ||
60e76d48 ZJS |
446 | r = mount_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL); |
447 | if (r < 0) | |
448 | return r; | |
d8fc6a00 | 449 | |
60e76d48 | 450 | r = mount_verbose(LOG_ERR, NULL, to, NULL, |
4f086aab | 451 | MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); |
60e76d48 ZJS |
452 | if (r < 0) |
453 | return r; | |
d8fc6a00 LP |
454 | } |
455 | ||
60e76d48 ZJS |
456 | r = umount_verbose(full); |
457 | if (r < 0) | |
458 | return r; | |
d8fc6a00 LP |
459 | |
460 | if (rmdir(full) < 0) | |
461 | return log_error_errno(errno, "Failed to remove %s: %m", full); | |
462 | ||
0996ef00 CB |
463 | /* Create mountpoint for cgroups. Otherwise we are not allowed since we |
464 | * remount /sys read-only. | |
465 | */ | |
677a72cd LS |
466 | x = prefix_roota(top, "/fs/cgroup"); |
467 | (void) mkdir_p(x, 0755); | |
d8fc6a00 | 468 | |
60e76d48 | 469 | return mount_verbose(LOG_ERR, NULL, top, NULL, |
4f086aab | 470 | MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); |
d8fc6a00 LP |
471 | } |
472 | ||
9c0fad5f | 473 | static int mkdir_userns(const char *path, mode_t mode, uid_t uid_shift) { |
63eae723 EV |
474 | int r; |
475 | ||
476 | assert(path); | |
477 | ||
dae8b82e ZJS |
478 | r = mkdir_errno_wrapper(path, mode); |
479 | if (r < 0 && r != -EEXIST) | |
480 | return r; | |
63eae723 | 481 | |
9c0fad5f | 482 | if (uid_shift == UID_INVALID) |
acbbf69b LP |
483 | return 0; |
484 | ||
dae8b82e | 485 | if (lchown(path, uid_shift, uid_shift) < 0) |
acbbf69b | 486 | return -errno; |
63eae723 EV |
487 | |
488 | return 0; | |
489 | } | |
490 | ||
9c0fad5f | 491 | static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, uid_t uid_shift) { |
63eae723 EV |
492 | const char *p, *e; |
493 | int r; | |
494 | ||
495 | assert(path); | |
496 | ||
497 | if (prefix && !path_startswith(path, prefix)) | |
498 | return -ENOTDIR; | |
499 | ||
500 | /* create every parent directory in the path, except the last component */ | |
501 | p = path + strspn(path, "/"); | |
502 | for (;;) { | |
503 | char t[strlen(path) + 1]; | |
504 | ||
505 | e = p + strcspn(p, "/"); | |
506 | p = e + strspn(e, "/"); | |
507 | ||
508 | /* Is this the last component? If so, then we're done */ | |
509 | if (*p == 0) | |
510 | break; | |
511 | ||
512 | memcpy(t, path, e - path); | |
513 | t[e-path] = 0; | |
514 | ||
515 | if (prefix && path_startswith(prefix, t)) | |
516 | continue; | |
517 | ||
9c0fad5f | 518 | r = mkdir_userns(t, mode, uid_shift); |
63eae723 EV |
519 | if (r < 0) |
520 | return r; | |
521 | } | |
522 | ||
9c0fad5f | 523 | return mkdir_userns(path, mode, uid_shift); |
63eae723 EV |
524 | } |
525 | ||
e83bebef | 526 | int mount_all(const char *dest, |
4f086aab | 527 | MountSettingsMask mount_settings, |
2fa017f1 | 528 | uid_t uid_shift, |
e83bebef LP |
529 | const char *selinux_apifs_context) { |
530 | ||
de40a303 LP |
531 | #define PROC_INACCESSIBLE_REG(path) \ |
532 | { "/run/systemd/inaccessible/reg", (path), NULL, NULL, MS_BIND, \ | |
533 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ | |
d4b653c5 LP |
534 | { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ |
535 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ | |
536 | ||
537 | #define PROC_READ_ONLY(path) \ | |
538 | { (path), (path), NULL, NULL, MS_BIND, \ | |
539 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ | |
540 | { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ | |
541 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ | |
542 | ||
e83bebef LP |
543 | typedef struct MountPoint { |
544 | const char *what; | |
545 | const char *where; | |
546 | const char *type; | |
547 | const char *options; | |
548 | unsigned long flags; | |
4f086aab | 549 | MountSettingsMask mount_settings; |
e83bebef LP |
550 | } MountPoint; |
551 | ||
552 | static const MountPoint mount_table[] = { | |
d4b653c5 LP |
553 | /* First we list inner child mounts (i.e. mounts applied *after* entering user namespacing) */ |
554 | { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
555 | MOUNT_FATAL|MOUNT_IN_USERNS }, | |
556 | ||
557 | { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, | |
558 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ | |
559 | ||
560 | { "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, | |
561 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_APPLY_APIVFS_NETNS }, /* (except for this) */ | |
562 | ||
563 | { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, | |
564 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */ | |
565 | ||
566 | /* Make these files inaccessible to container payloads: they potentially leak information about kernel | |
567 | * internals or the host's execution environment to the container */ | |
de40a303 LP |
568 | PROC_INACCESSIBLE_REG("/proc/kallsyms"), |
569 | PROC_INACCESSIBLE_REG("/proc/kcore"), | |
570 | PROC_INACCESSIBLE_REG("/proc/keys"), | |
571 | PROC_INACCESSIBLE_REG("/proc/sysrq-trigger"), | |
572 | PROC_INACCESSIBLE_REG("/proc/timer_list"), | |
d4b653c5 LP |
573 | |
574 | /* Make these directories read-only to container payloads: they show hardware information, and in some | |
575 | * cases contain tunables the container really shouldn't have access to. */ | |
576 | PROC_READ_ONLY("/proc/acpi"), | |
577 | PROC_READ_ONLY("/proc/apm"), | |
578 | PROC_READ_ONLY("/proc/asound"), | |
579 | PROC_READ_ONLY("/proc/bus"), | |
580 | PROC_READ_ONLY("/proc/fs"), | |
581 | PROC_READ_ONLY("/proc/irq"), | |
582 | PROC_READ_ONLY("/proc/scsi"), | |
583 | ||
849b9b85 LP |
584 | { "mqueue", "/dev/mqueue", "mqueue", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
585 | MOUNT_IN_USERNS }, | |
586 | ||
d4b653c5 LP |
587 | /* Then we list outer child mounts (i.e. mounts applied *before* entering user namespacing) */ |
588 | { "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
1099ceeb | 589 | MOUNT_FATAL|MOUNT_APPLY_TMPFS_TMP }, |
03d0f4b5 | 590 | { "tmpfs", "/sys", "tmpfs", "mode=555", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
d4b653c5 LP |
591 | MOUNT_FATAL|MOUNT_APPLY_APIVFS_NETNS }, |
592 | { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
593 | MOUNT_FATAL|MOUNT_APPLY_APIVFS_RO }, /* skipped if above was mounted */ | |
594 | { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
595 | MOUNT_FATAL }, /* skipped if above was mounted */ | |
596 | { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, | |
597 | MOUNT_FATAL }, | |
598 | { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
599 | MOUNT_FATAL }, | |
600 | { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, | |
601 | MOUNT_FATAL }, | |
602 | ||
349cc4a5 | 603 | #if HAVE_SELINUX |
d4b653c5 LP |
604 | { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, |
605 | 0 }, /* Bind mount first */ | |
606 | { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, | |
607 | 0 }, /* Then, make it r/o */ | |
e83bebef LP |
608 | #endif |
609 | }; | |
610 | ||
4f086aab SU |
611 | bool use_userns = (mount_settings & MOUNT_USE_USERNS); |
612 | bool netns = (mount_settings & MOUNT_APPLY_APIVFS_NETNS); | |
613 | bool ro = (mount_settings & MOUNT_APPLY_APIVFS_RO); | |
614 | bool in_userns = (mount_settings & MOUNT_IN_USERNS); | |
1099ceeb | 615 | bool tmpfs_tmp = (mount_settings & MOUNT_APPLY_TMPFS_TMP); |
d4b653c5 | 616 | size_t k; |
88614c8a | 617 | int r; |
e83bebef LP |
618 | |
619 | for (k = 0; k < ELEMENTSOF(mount_table); k++) { | |
620 | _cleanup_free_ char *where = NULL, *options = NULL; | |
de40a303 | 621 | const char *o; |
4f086aab SU |
622 | bool fatal = (mount_table[k].mount_settings & MOUNT_FATAL); |
623 | ||
624 | if (in_userns != (bool)(mount_table[k].mount_settings & MOUNT_IN_USERNS)) | |
625 | continue; | |
e83bebef | 626 | |
4f086aab | 627 | if (!netns && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_APIVFS_NETNS)) |
d1678248 ILG |
628 | continue; |
629 | ||
4f086aab | 630 | if (!ro && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_APIVFS_RO)) |
e83bebef LP |
631 | continue; |
632 | ||
1099ceeb LP |
633 | if (!tmpfs_tmp && (bool)(mount_table[k].mount_settings & MOUNT_APPLY_TMPFS_TMP)) |
634 | continue; | |
635 | ||
cb638b5e | 636 | r = chase_symlinks(mount_table[k].where, dest, CHASE_NONEXISTENT|CHASE_PREFIX_ROOT, &where); |
8ce48cf0 | 637 | if (r < 0) |
ec57bd42 | 638 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].where); |
e83bebef | 639 | |
e83bebef | 640 | /* Skip this entry if it is not a remount. */ |
de40a303 LP |
641 | if (mount_table[k].what) { |
642 | r = path_is_mount_point(where, NULL, 0); | |
643 | if (r < 0 && r != -ENOENT) | |
644 | return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); | |
645 | if (r > 0) | |
646 | continue; | |
647 | } | |
e83bebef | 648 | |
9c0fad5f | 649 | r = mkdir_userns_p(dest, where, 0755, (use_userns && !in_userns) ? uid_shift : UID_INVALID); |
920a7899 | 650 | if (r < 0 && r != -EEXIST) { |
4f13e534 | 651 | if (fatal && r != -EROFS) |
e83bebef LP |
652 | return log_error_errno(r, "Failed to create directory %s: %m", where); |
653 | ||
201b13c8 | 654 | log_debug_errno(r, "Failed to create directory %s: %m", where); |
4f13e534 LT |
655 | /* If we failed mkdir() or chown() due to the root |
656 | * directory being read only, attempt to mount this fs | |
657 | * anyway and let mount_verbose log any errors */ | |
658 | if (r != -EROFS) | |
659 | continue; | |
e83bebef LP |
660 | } |
661 | ||
662 | o = mount_table[k].options; | |
663 | if (streq_ptr(mount_table[k].type, "tmpfs")) { | |
2fa017f1 | 664 | r = tmpfs_patch_options(o, in_userns ? 0 : uid_shift, selinux_apifs_context, &options); |
e83bebef LP |
665 | if (r < 0) |
666 | return log_oom(); | |
667 | if (r > 0) | |
668 | o = options; | |
669 | } | |
670 | ||
4f086aab | 671 | r = mount_verbose(fatal ? LOG_ERR : LOG_DEBUG, |
de40a303 | 672 | mount_table[k].what, |
60e76d48 ZJS |
673 | where, |
674 | mount_table[k].type, | |
675 | mount_table[k].flags, | |
676 | o); | |
4f086aab | 677 | if (r < 0 && fatal) |
60e76d48 | 678 | return r; |
e83bebef LP |
679 | } |
680 | ||
681 | return 0; | |
682 | } | |
683 | ||
e83bebef | 684 | static int mount_bind(const char *dest, CustomMount *m) { |
72d967df | 685 | _cleanup_free_ char *where = NULL; |
68cf43c3 | 686 | struct stat source_st, dest_st; |
e83bebef LP |
687 | int r; |
688 | ||
86c0dd4a | 689 | assert(dest); |
e83bebef LP |
690 | assert(m); |
691 | ||
e83bebef LP |
692 | if (stat(m->source, &source_st) < 0) |
693 | return log_error_errno(errno, "Failed to stat %s: %m", m->source); | |
694 | ||
cb638b5e | 695 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where); |
68cf43c3 | 696 | if (r < 0) |
ec57bd42 | 697 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
698 | if (r > 0) { /* Path exists already? */ |
699 | ||
700 | if (stat(where, &dest_st) < 0) | |
701 | return log_error_errno(errno, "Failed to stat %s: %m", where); | |
e83bebef | 702 | |
baaa35ad ZJS |
703 | if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) |
704 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), | |
705 | "Cannot bind mount directory %s on file %s.", | |
706 | m->source, where); | |
707 | ||
708 | if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) | |
709 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), | |
710 | "Cannot bind mount file %s on directory %s.", | |
711 | m->source, where); | |
e83bebef | 712 | |
8ce48cf0 | 713 | } else { /* Path doesn't exist yet? */ |
e83bebef LP |
714 | r = mkdir_parents_label(where, 0755); |
715 | if (r < 0) | |
716 | return log_error_errno(r, "Failed to make parents of %s: %m", where); | |
b97e83cb BN |
717 | |
718 | /* Create the mount point. Any non-directory file can be | |
719 | * mounted on any non-directory file (regular, fifo, socket, | |
720 | * char, block). | |
721 | */ | |
722 | if (S_ISDIR(source_st.st_mode)) | |
723 | r = mkdir_label(where, 0755); | |
724 | else | |
725 | r = touch(where); | |
726 | if (r < 0) | |
727 | return log_error_errno(r, "Failed to create mount point %s: %m", where); | |
8ce48cf0 | 728 | } |
e83bebef | 729 | |
72d967df | 730 | r = mount_verbose(LOG_ERR, m->source, where, NULL, MS_BIND | MS_REC, m->options); |
60e76d48 ZJS |
731 | if (r < 0) |
732 | return r; | |
e83bebef LP |
733 | |
734 | if (m->read_only) { | |
64e82c19 | 735 | r = bind_remount_recursive(where, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
736 | if (r < 0) |
737 | return log_error_errno(r, "Read-only bind mount failed: %m"); | |
738 | } | |
739 | ||
740 | return 0; | |
741 | } | |
742 | ||
743 | static int mount_tmpfs( | |
744 | const char *dest, | |
745 | CustomMount *m, | |
746 | bool userns, uid_t uid_shift, uid_t uid_range, | |
747 | const char *selinux_apifs_context) { | |
748 | ||
68cf43c3 LP |
749 | const char *options; |
750 | _cleanup_free_ char *buf = NULL, *where = NULL; | |
e83bebef LP |
751 | int r; |
752 | ||
753 | assert(dest); | |
754 | assert(m); | |
755 | ||
cb638b5e | 756 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where); |
68cf43c3 | 757 | if (r < 0) |
ec57bd42 | 758 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
759 | if (r == 0) { /* Doesn't exist yet? */ |
760 | r = mkdir_p_label(where, 0755); | |
761 | if (r < 0) | |
762 | return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); | |
763 | } | |
e83bebef | 764 | |
2fa017f1 | 765 | r = tmpfs_patch_options(m->options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef LP |
766 | if (r < 0) |
767 | return log_oom(); | |
768 | options = r > 0 ? buf : m->options; | |
769 | ||
60e76d48 | 770 | return mount_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options); |
e83bebef LP |
771 | } |
772 | ||
86c0dd4a | 773 | static char *joined_and_escaped_lower_dirs(char **lower) { |
e83bebef LP |
774 | _cleanup_strv_free_ char **sv = NULL; |
775 | ||
776 | sv = strv_copy(lower); | |
777 | if (!sv) | |
778 | return NULL; | |
779 | ||
780 | strv_reverse(sv); | |
781 | ||
782 | if (!strv_shell_escape(sv, ",:")) | |
783 | return NULL; | |
784 | ||
785 | return strv_join(sv, ":"); | |
786 | } | |
787 | ||
788 | static int mount_overlay(const char *dest, CustomMount *m) { | |
86c0dd4a | 789 | _cleanup_free_ char *lower = NULL, *where = NULL, *escaped_source = NULL; |
68cf43c3 | 790 | const char *options; |
e83bebef LP |
791 | int r; |
792 | ||
793 | assert(dest); | |
794 | assert(m); | |
795 | ||
cb638b5e | 796 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where); |
68cf43c3 | 797 | if (r < 0) |
ec57bd42 | 798 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
799 | if (r == 0) { /* Doesn't exist yet? */ |
800 | r = mkdir_label(where, 0755); | |
801 | if (r < 0) | |
802 | return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where); | |
803 | } | |
e83bebef LP |
804 | |
805 | (void) mkdir_p_label(m->source, 0755); | |
806 | ||
807 | lower = joined_and_escaped_lower_dirs(m->lower); | |
808 | if (!lower) | |
809 | return log_oom(); | |
810 | ||
86c0dd4a LP |
811 | escaped_source = shell_escape(m->source, ",:"); |
812 | if (!escaped_source) | |
813 | return log_oom(); | |
e83bebef | 814 | |
86c0dd4a | 815 | if (m->read_only) |
e83bebef | 816 | options = strjoina("lowerdir=", escaped_source, ":", lower); |
86c0dd4a LP |
817 | else { |
818 | _cleanup_free_ char *escaped_work_dir = NULL; | |
e83bebef | 819 | |
e83bebef LP |
820 | escaped_work_dir = shell_escape(m->work_dir, ",:"); |
821 | if (!escaped_work_dir) | |
822 | return log_oom(); | |
823 | ||
824 | options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir); | |
825 | } | |
826 | ||
60e76d48 | 827 | return mount_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options); |
e83bebef LP |
828 | } |
829 | ||
de40a303 LP |
830 | static int mount_inaccessible(const char *dest, CustomMount *m) { |
831 | _cleanup_free_ char *where = NULL; | |
832 | const char *source; | |
833 | struct stat st; | |
834 | int r; | |
835 | ||
836 | assert(dest); | |
837 | assert(m); | |
838 | ||
839 | r = chase_symlinks_and_stat(m->destination, dest, CHASE_PREFIX_ROOT, &where, &st); | |
840 | if (r < 0) { | |
841 | log_full_errno(m->graceful ? LOG_DEBUG : LOG_ERR, r, "Failed to resolve %s/%s: %m", dest, m->destination); | |
842 | return m->graceful ? 0 : r; | |
843 | } | |
844 | ||
845 | assert_se(source = mode_to_inaccessible_node(st.st_mode)); | |
846 | ||
847 | r = mount_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, source, where, NULL, MS_BIND, NULL); | |
848 | if (r < 0) | |
849 | return m->graceful ? 0 : r; | |
850 | ||
851 | r = mount_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, NULL, where, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL); | |
2c9b7a7e LP |
852 | if (r < 0) { |
853 | umount_verbose(where); | |
de40a303 | 854 | return m->graceful ? 0 : r; |
2c9b7a7e | 855 | } |
de40a303 LP |
856 | |
857 | return 0; | |
858 | } | |
859 | ||
860 | static int mount_arbitrary(const char *dest, CustomMount *m) { | |
861 | _cleanup_free_ char *where = NULL; | |
862 | int r; | |
863 | ||
864 | assert(dest); | |
865 | assert(m); | |
866 | ||
867 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where); | |
868 | if (r < 0) | |
869 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); | |
870 | if (r == 0) { /* Doesn't exist yet? */ | |
871 | r = mkdir_p_label(where, 0755); | |
872 | if (r < 0) | |
873 | return log_error_errno(r, "Creating mount point for mount %s failed: %m", where); | |
874 | } | |
875 | ||
876 | return mount_verbose(LOG_ERR, m->source, where, m->type_argument, 0, m->options); | |
877 | } | |
878 | ||
e83bebef LP |
879 | int mount_custom( |
880 | const char *dest, | |
88614c8a | 881 | CustomMount *mounts, size_t n, |
e83bebef | 882 | bool userns, uid_t uid_shift, uid_t uid_range, |
de40a303 LP |
883 | const char *selinux_apifs_context, |
884 | bool in_userns) { | |
e83bebef | 885 | |
88614c8a | 886 | size_t i; |
e83bebef LP |
887 | int r; |
888 | ||
889 | assert(dest); | |
890 | ||
891 | for (i = 0; i < n; i++) { | |
892 | CustomMount *m = mounts + i; | |
893 | ||
de40a303 LP |
894 | if (m->in_userns != in_userns) |
895 | continue; | |
896 | ||
e83bebef LP |
897 | switch (m->type) { |
898 | ||
899 | case CUSTOM_MOUNT_BIND: | |
900 | r = mount_bind(dest, m); | |
901 | break; | |
902 | ||
903 | case CUSTOM_MOUNT_TMPFS: | |
904 | r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context); | |
905 | break; | |
906 | ||
907 | case CUSTOM_MOUNT_OVERLAY: | |
908 | r = mount_overlay(dest, m); | |
909 | break; | |
910 | ||
de40a303 LP |
911 | case CUSTOM_MOUNT_INACCESSIBLE: |
912 | r = mount_inaccessible(dest, m); | |
913 | break; | |
914 | ||
915 | case CUSTOM_MOUNT_ARBITRARY: | |
916 | r = mount_arbitrary(dest, m); | |
917 | break; | |
918 | ||
e83bebef LP |
919 | default: |
920 | assert_not_reached("Unknown custom mount type"); | |
921 | } | |
922 | ||
923 | if (r < 0) | |
924 | return r; | |
925 | } | |
926 | ||
927 | return 0; | |
928 | } | |
929 | ||
e5b43a04 | 930 | static int setup_volatile_state( |
e83bebef | 931 | const char *directory, |
e83bebef LP |
932 | bool userns, uid_t uid_shift, uid_t uid_range, |
933 | const char *selinux_apifs_context) { | |
934 | ||
935 | _cleanup_free_ char *buf = NULL; | |
936 | const char *p, *options; | |
937 | int r; | |
938 | ||
939 | assert(directory); | |
940 | ||
e5b43a04 | 941 | /* --volatile=state means we simply overmount /var with a tmpfs, and the rest read-only. */ |
e83bebef | 942 | |
64e82c19 | 943 | r = bind_remount_recursive(directory, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
944 | if (r < 0) |
945 | return log_error_errno(r, "Failed to remount %s read-only: %m", directory); | |
946 | ||
947 | p = prefix_roota(directory, "/var"); | |
948 | r = mkdir(p, 0755); | |
949 | if (r < 0 && errno != EEXIST) | |
950 | return log_error_errno(errno, "Failed to create %s: %m", directory); | |
951 | ||
952 | options = "mode=755"; | |
2fa017f1 | 953 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef LP |
954 | if (r < 0) |
955 | return log_oom(); | |
956 | if (r > 0) | |
957 | options = buf; | |
958 | ||
60e76d48 | 959 | return mount_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options); |
e83bebef LP |
960 | } |
961 | ||
e5b43a04 | 962 | static int setup_volatile_yes( |
e83bebef | 963 | const char *directory, |
e83bebef LP |
964 | bool userns, uid_t uid_shift, uid_t uid_range, |
965 | const char *selinux_apifs_context) { | |
966 | ||
967 | bool tmpfs_mounted = false, bind_mounted = false; | |
968 | char template[] = "/tmp/nspawn-volatile-XXXXXX"; | |
969 | _cleanup_free_ char *buf = NULL; | |
970 | const char *f, *t, *options; | |
971 | int r; | |
972 | ||
973 | assert(directory); | |
974 | ||
e5b43a04 LP |
975 | /* --volatile=yes means we mount a tmpfs to the root dir, and the original /usr to use inside it, and that |
976 | read-only. */ | |
e83bebef LP |
977 | |
978 | if (!mkdtemp(template)) | |
979 | return log_error_errno(errno, "Failed to create temporary directory: %m"); | |
980 | ||
981 | options = "mode=755"; | |
2fa017f1 | 982 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef | 983 | if (r < 0) |
c55d0ae7 | 984 | goto fail; |
e83bebef LP |
985 | if (r > 0) |
986 | options = buf; | |
987 | ||
60e76d48 ZJS |
988 | r = mount_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); |
989 | if (r < 0) | |
e83bebef | 990 | goto fail; |
e83bebef LP |
991 | |
992 | tmpfs_mounted = true; | |
993 | ||
994 | f = prefix_roota(directory, "/usr"); | |
995 | t = prefix_roota(template, "/usr"); | |
996 | ||
997 | r = mkdir(t, 0755); | |
998 | if (r < 0 && errno != EEXIST) { | |
999 | r = log_error_errno(errno, "Failed to create %s: %m", t); | |
1000 | goto fail; | |
1001 | } | |
1002 | ||
60e76d48 ZJS |
1003 | r = mount_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL); |
1004 | if (r < 0) | |
e83bebef | 1005 | goto fail; |
e83bebef LP |
1006 | |
1007 | bind_mounted = true; | |
1008 | ||
64e82c19 | 1009 | r = bind_remount_recursive(t, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
1010 | if (r < 0) { |
1011 | log_error_errno(r, "Failed to remount %s read-only: %m", t); | |
1012 | goto fail; | |
1013 | } | |
1014 | ||
60e76d48 ZJS |
1015 | r = mount_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL); |
1016 | if (r < 0) | |
e83bebef | 1017 | goto fail; |
e83bebef LP |
1018 | |
1019 | (void) rmdir(template); | |
1020 | ||
1021 | return 0; | |
1022 | ||
1023 | fail: | |
1024 | if (bind_mounted) | |
60e76d48 | 1025 | (void) umount_verbose(t); |
e83bebef LP |
1026 | |
1027 | if (tmpfs_mounted) | |
60e76d48 | 1028 | (void) umount_verbose(template); |
e83bebef LP |
1029 | (void) rmdir(template); |
1030 | return r; | |
1031 | } | |
b53ede69 | 1032 | |
6c610aca LP |
1033 | static int setup_volatile_overlay( |
1034 | const char *directory, | |
1035 | bool userns, uid_t uid_shift, uid_t uid_range, | |
1036 | const char *selinux_apifs_context) { | |
1037 | ||
1038 | _cleanup_free_ char *buf = NULL, *escaped_directory = NULL, *escaped_upper = NULL, *escaped_work = NULL; | |
1039 | char template[] = "/tmp/nspawn-volatile-XXXXXX"; | |
1040 | const char *upper, *work, *options; | |
1041 | bool tmpfs_mounted = false; | |
1042 | int r; | |
1043 | ||
1044 | assert(directory); | |
1045 | ||
1046 | /* --volatile=overlay means we mount an overlayfs to the root dir. */ | |
1047 | ||
1048 | if (!mkdtemp(template)) | |
1049 | return log_error_errno(errno, "Failed to create temporary directory: %m"); | |
1050 | ||
1051 | options = "mode=755"; | |
1052 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); | |
1053 | if (r < 0) | |
1054 | goto finish; | |
1055 | if (r > 0) | |
1056 | options = buf; | |
1057 | ||
1058 | r = mount_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); | |
1059 | if (r < 0) | |
1060 | goto finish; | |
1061 | ||
1062 | tmpfs_mounted = true; | |
1063 | ||
1064 | upper = strjoina(template, "/upper"); | |
1065 | work = strjoina(template, "/work"); | |
1066 | ||
1067 | if (mkdir(upper, 0755) < 0) { | |
1068 | r = log_error_errno(errno, "Failed to create %s: %m", upper); | |
1069 | goto finish; | |
1070 | } | |
1071 | if (mkdir(work, 0755) < 0) { | |
1072 | r = log_error_errno(errno, "Failed to create %s: %m", work); | |
1073 | goto finish; | |
1074 | } | |
1075 | ||
1076 | /* And now, let's overmount the root dir with an overlayfs that uses the root dir as lower dir. It's kinda nice | |
1077 | * that the kernel allows us to do that without going through some mount point rearrangements. */ | |
1078 | ||
1079 | escaped_directory = shell_escape(directory, ",:"); | |
1080 | escaped_upper = shell_escape(upper, ",:"); | |
1081 | escaped_work = shell_escape(work, ",:"); | |
1082 | if (!escaped_directory || !escaped_upper || !escaped_work) { | |
1083 | r = -ENOMEM; | |
1084 | goto finish; | |
1085 | } | |
1086 | ||
1087 | options = strjoina("lowerdir=", escaped_directory, ",upperdir=", escaped_upper, ",workdir=", escaped_work); | |
1088 | r = mount_verbose(LOG_ERR, "overlay", directory, "overlay", 0, options); | |
1089 | ||
1090 | finish: | |
1091 | if (tmpfs_mounted) | |
1092 | (void) umount_verbose(template); | |
1093 | ||
1094 | (void) rmdir(template); | |
1095 | return r; | |
1096 | } | |
1097 | ||
e5b43a04 LP |
1098 | int setup_volatile_mode( |
1099 | const char *directory, | |
1100 | VolatileMode mode, | |
1101 | bool userns, uid_t uid_shift, uid_t uid_range, | |
1102 | const char *selinux_apifs_context) { | |
1103 | ||
1104 | switch (mode) { | |
1105 | ||
1106 | case VOLATILE_YES: | |
1107 | return setup_volatile_yes(directory, userns, uid_shift, uid_range, selinux_apifs_context); | |
1108 | ||
1109 | case VOLATILE_STATE: | |
1110 | return setup_volatile_state(directory, userns, uid_shift, uid_range, selinux_apifs_context); | |
1111 | ||
6c610aca LP |
1112 | case VOLATILE_OVERLAY: |
1113 | return setup_volatile_overlay(directory, userns, uid_shift, uid_range, selinux_apifs_context); | |
1114 | ||
e5b43a04 LP |
1115 | default: |
1116 | return 0; | |
1117 | } | |
1118 | } | |
1119 | ||
b53ede69 PW |
1120 | /* Expects *pivot_root_new and *pivot_root_old to be initialised to allocated memory or NULL. */ |
1121 | int pivot_root_parse(char **pivot_root_new, char **pivot_root_old, const char *s) { | |
1122 | _cleanup_free_ char *root_new = NULL, *root_old = NULL; | |
1123 | const char *p = s; | |
1124 | int r; | |
1125 | ||
1126 | assert(pivot_root_new); | |
1127 | assert(pivot_root_old); | |
1128 | ||
1129 | r = extract_first_word(&p, &root_new, ":", EXTRACT_DONT_COALESCE_SEPARATORS); | |
1130 | if (r < 0) | |
1131 | return r; | |
1132 | if (r == 0) | |
1133 | return -EINVAL; | |
1134 | ||
1135 | if (isempty(p)) | |
1136 | root_old = NULL; | |
1137 | else { | |
1138 | root_old = strdup(p); | |
1139 | if (!root_old) | |
1140 | return -ENOMEM; | |
1141 | } | |
1142 | ||
1143 | if (!path_is_absolute(root_new)) | |
1144 | return -EINVAL; | |
1145 | if (root_old && !path_is_absolute(root_old)) | |
1146 | return -EINVAL; | |
1147 | ||
1148 | free_and_replace(*pivot_root_new, root_new); | |
1149 | free_and_replace(*pivot_root_old, root_old); | |
1150 | ||
1151 | return 0; | |
1152 | } | |
1153 | ||
1154 | int setup_pivot_root(const char *directory, const char *pivot_root_new, const char *pivot_root_old) { | |
1155 | _cleanup_free_ char *directory_pivot_root_new = NULL; | |
1156 | _cleanup_free_ char *pivot_tmp_pivot_root_old = NULL; | |
1157 | char pivot_tmp[] = "/tmp/nspawn-pivot-XXXXXX"; | |
1158 | bool remove_pivot_tmp = false; | |
1159 | int r; | |
1160 | ||
1161 | assert(directory); | |
1162 | ||
1163 | if (!pivot_root_new) | |
1164 | return 0; | |
1165 | ||
1166 | /* Pivot pivot_root_new to / and the existing / to pivot_root_old. | |
1167 | * If pivot_root_old is NULL, the existing / disappears. | |
1168 | * This requires a temporary directory, pivot_tmp, which is | |
1169 | * not a child of either. | |
1170 | * | |
1171 | * This is typically used for OSTree-style containers, where | |
1172 | * the root partition contains several sysroots which could be | |
1173 | * run. Normally, one would be chosen by the bootloader and | |
1174 | * pivoted to / by initramfs. | |
1175 | * | |
1176 | * For example, for an OSTree deployment, pivot_root_new | |
1177 | * would be: /ostree/deploy/$os/deploy/$checksum. Note that this | |
1178 | * code doesn’t do the /var mount which OSTree expects: use | |
1179 | * --bind +/sysroot/ostree/deploy/$os/var:/var for that. | |
1180 | * | |
1181 | * So in the OSTree case, we’ll end up with something like: | |
1182 | * - directory = /tmp/nspawn-root-123456 | |
1183 | * - pivot_root_new = /ostree/deploy/os/deploy/123abc | |
1184 | * - pivot_root_old = /sysroot | |
1185 | * - directory_pivot_root_new = | |
1186 | * /tmp/nspawn-root-123456/ostree/deploy/os/deploy/123abc | |
1187 | * - pivot_tmp = /tmp/nspawn-pivot-123456 | |
1188 | * - pivot_tmp_pivot_root_old = /tmp/nspawn-pivot-123456/sysroot | |
1189 | * | |
1190 | * Requires all file systems at directory and below to be mounted | |
1191 | * MS_PRIVATE or MS_SLAVE so they can be moved. | |
1192 | */ | |
1193 | directory_pivot_root_new = prefix_root(directory, pivot_root_new); | |
1194 | ||
1195 | /* Remount directory_pivot_root_new to make it movable. */ | |
1196 | r = mount_verbose(LOG_ERR, directory_pivot_root_new, directory_pivot_root_new, NULL, MS_BIND, NULL); | |
1197 | if (r < 0) | |
1198 | goto done; | |
1199 | ||
1200 | if (pivot_root_old) { | |
1201 | if (!mkdtemp(pivot_tmp)) { | |
1202 | r = log_error_errno(errno, "Failed to create temporary directory: %m"); | |
1203 | goto done; | |
1204 | } | |
1205 | ||
1206 | remove_pivot_tmp = true; | |
1207 | pivot_tmp_pivot_root_old = prefix_root(pivot_tmp, pivot_root_old); | |
1208 | ||
1209 | r = mount_verbose(LOG_ERR, directory_pivot_root_new, pivot_tmp, NULL, MS_MOVE, NULL); | |
1210 | if (r < 0) | |
1211 | goto done; | |
1212 | ||
1213 | r = mount_verbose(LOG_ERR, directory, pivot_tmp_pivot_root_old, NULL, MS_MOVE, NULL); | |
1214 | if (r < 0) | |
1215 | goto done; | |
1216 | ||
1217 | r = mount_verbose(LOG_ERR, pivot_tmp, directory, NULL, MS_MOVE, NULL); | |
1218 | if (r < 0) | |
1219 | goto done; | |
1220 | } else { | |
1221 | r = mount_verbose(LOG_ERR, directory_pivot_root_new, directory, NULL, MS_MOVE, NULL); | |
1222 | if (r < 0) | |
1223 | goto done; | |
1224 | } | |
1225 | ||
1226 | done: | |
1227 | if (remove_pivot_tmp) | |
1228 | (void) rmdir(pivot_tmp); | |
1229 | ||
1230 | return r; | |
1231 | } |