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db9ecf05 | 1 | /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
e83bebef | 2 | |
4f5dd394 | 3 | #include <sys/mount.h> |
07630cea | 4 | #include <linux/magic.h> |
e83bebef | 5 | |
b5efdb8a | 6 | #include "alloc-util.h" |
f4351959 | 7 | #include "chase-symlinks.h" |
4f5dd394 | 8 | #include "escape.h" |
0996ef00 | 9 | #include "fd-util.h" |
ca78ad1d | 10 | #include "format-util.h" |
f4f15635 | 11 | #include "fs-util.h" |
e83bebef | 12 | #include "label.h" |
35cd0ba5 | 13 | #include "mkdir-label.h" |
4349cd7c | 14 | #include "mount-util.h" |
049af8ad | 15 | #include "mountpoint-util.h" |
6bedfcbb LP |
16 | #include "nspawn-mount.h" |
17 | #include "parse-util.h" | |
4f5dd394 LP |
18 | #include "path-util.h" |
19 | #include "rm-rf.h" | |
e83bebef | 20 | #include "set.h" |
760877e9 | 21 | #include "sort-util.h" |
8fcde012 | 22 | #include "stat-util.h" |
07630cea | 23 | #include "string-util.h" |
4f5dd394 | 24 | #include "strv.h" |
e4de7287 | 25 | #include "tmpfile-util.h" |
ee104e11 | 26 | #include "user-util.h" |
e83bebef | 27 | |
88614c8a | 28 | CustomMount* custom_mount_add(CustomMount **l, size_t *n, CustomMountType t) { |
e83bebef LP |
29 | CustomMount *c, *ret; |
30 | ||
31 | assert(l); | |
32 | assert(n); | |
33 | assert(t >= 0); | |
34 | assert(t < _CUSTOM_MOUNT_TYPE_MAX); | |
35 | ||
aa484f35 | 36 | c = reallocarray(*l, *n + 1, sizeof(CustomMount)); |
e83bebef LP |
37 | if (!c) |
38 | return NULL; | |
39 | ||
40 | *l = c; | |
41 | ret = *l + *n; | |
42 | (*n)++; | |
43 | ||
511a8cfe LP |
44 | *ret = (CustomMount) { |
45 | .type = t | |
46 | }; | |
e83bebef LP |
47 | |
48 | return ret; | |
49 | } | |
50 | ||
88614c8a | 51 | void custom_mount_free_all(CustomMount *l, size_t n) { |
d2b99ed7 | 52 | for (size_t i = 0; i < n; i++) { |
e83bebef LP |
53 | CustomMount *m = l + i; |
54 | ||
55 | free(m->source); | |
56 | free(m->destination); | |
57 | free(m->options); | |
58 | ||
59 | if (m->work_dir) { | |
60 | (void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL); | |
61 | free(m->work_dir); | |
62 | } | |
63 | ||
c7a4890c LP |
64 | if (m->rm_rf_tmpdir) { |
65 | (void) rm_rf(m->rm_rf_tmpdir, REMOVE_ROOT|REMOVE_PHYSICAL); | |
66 | free(m->rm_rf_tmpdir); | |
67 | } | |
68 | ||
e83bebef | 69 | strv_free(m->lower); |
de40a303 | 70 | free(m->type_argument); |
e83bebef LP |
71 | } |
72 | ||
73 | free(l); | |
74 | } | |
75 | ||
93bab288 | 76 | static int custom_mount_compare(const CustomMount *a, const CustomMount *b) { |
e83bebef LP |
77 | int r; |
78 | ||
93bab288 | 79 | r = path_compare(a->destination, b->destination); |
e83bebef LP |
80 | if (r != 0) |
81 | return r; | |
82 | ||
93bab288 | 83 | return CMP(a->type, b->type); |
e83bebef LP |
84 | } |
85 | ||
448f7377 | 86 | static int source_path_parse(const char *p, char **ret) { |
86c0dd4a | 87 | assert(p); |
448f7377 | 88 | assert(ret); |
86c0dd4a | 89 | |
448f7377 DDM |
90 | if (isempty(p)) |
91 | return -EINVAL; | |
92 | ||
93 | if (*p == '+') { | |
94 | if (!path_is_absolute(p + 1)) | |
95 | return -EINVAL; | |
96 | ||
97 | char *s = strdup(p); | |
98 | if (!s) | |
99 | return -ENOMEM; | |
100 | ||
101 | *ret = TAKE_PTR(s); | |
102 | return 0; | |
103 | } | |
104 | ||
105 | return path_make_absolute_cwd(p, ret); | |
106 | } | |
107 | ||
108 | static int source_path_parse_nullable(const char *p, char **ret) { | |
109 | assert(p); | |
110 | assert(ret); | |
111 | ||
112 | if (isempty(p)) { | |
113 | *ret = NULL; | |
114 | return 0; | |
115 | } | |
86c0dd4a | 116 | |
448f7377 | 117 | return source_path_parse(p, ret); |
86c0dd4a LP |
118 | } |
119 | ||
120 | static char *resolve_source_path(const char *dest, const char *source) { | |
86c0dd4a LP |
121 | if (!source) |
122 | return NULL; | |
123 | ||
124 | if (source[0] == '+') | |
c6134d3e | 125 | return path_join(dest, source + 1); |
86c0dd4a LP |
126 | |
127 | return strdup(source); | |
128 | } | |
129 | ||
d0556c55 LP |
130 | static int allocate_temporary_source(CustomMount *m) { |
131 | assert(m); | |
132 | assert(!m->source); | |
133 | assert(!m->rm_rf_tmpdir); | |
134 | ||
135 | m->rm_rf_tmpdir = strdup("/var/tmp/nspawn-temp-XXXXXX"); | |
136 | if (!m->rm_rf_tmpdir) | |
137 | return log_oom(); | |
138 | ||
139 | if (!mkdtemp(m->rm_rf_tmpdir)) { | |
140 | m->rm_rf_tmpdir = mfree(m->rm_rf_tmpdir); | |
141 | return log_error_errno(errno, "Failed to acquire temporary directory: %m"); | |
142 | } | |
143 | ||
144 | m->source = path_join(m->rm_rf_tmpdir, "src"); | |
145 | if (!m->source) | |
146 | return log_oom(); | |
147 | ||
148 | if (mkdir(m->source, 0755) < 0) | |
149 | return log_error_errno(errno, "Failed to create %s: %m", m->source); | |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
88614c8a | 154 | int custom_mount_prepare_all(const char *dest, CustomMount *l, size_t n) { |
86c0dd4a LP |
155 | int r; |
156 | ||
157 | /* Prepare all custom mounts. This will make source we know all temporary directories. This is called in the | |
158 | * parent process, so that we know the temporary directories to remove on exit before we fork off the | |
159 | * children. */ | |
160 | ||
161 | assert(l || n == 0); | |
162 | ||
163 | /* Order the custom mounts, and make sure we have a working directory */ | |
93bab288 | 164 | typesafe_qsort(l, n, custom_mount_compare); |
86c0dd4a | 165 | |
d2b99ed7 | 166 | for (size_t i = 0; i < n; i++) { |
86c0dd4a LP |
167 | CustomMount *m = l + i; |
168 | ||
de40a303 LP |
169 | /* /proc we mount in the inner child, i.e. when we acquired CLONE_NEWPID. All other mounts we mount |
170 | * already in the outer child, so that the mounts are already established before CLONE_NEWPID and in | |
171 | * particular CLONE_NEWUSER. This also means any custom mounts below /proc also need to be mounted in | |
172 | * the inner child, not the outer one. Determine this here. */ | |
173 | m->in_userns = path_startswith(m->destination, "/proc"); | |
86c0dd4a | 174 | |
de40a303 LP |
175 | if (m->type == CUSTOM_MOUNT_BIND) { |
176 | if (m->source) { | |
177 | char *s; | |
86c0dd4a | 178 | |
de40a303 LP |
179 | s = resolve_source_path(dest, m->source); |
180 | if (!s) | |
181 | return log_oom(); | |
c7a4890c | 182 | |
de40a303 LP |
183 | free_and_replace(m->source, s); |
184 | } else { | |
185 | /* No source specified? In that case, use a throw-away temporary directory in /var/tmp */ | |
c7a4890c | 186 | |
d0556c55 LP |
187 | r = allocate_temporary_source(m); |
188 | if (r < 0) | |
189 | return r; | |
de40a303 | 190 | } |
86c0dd4a LP |
191 | } |
192 | ||
193 | if (m->type == CUSTOM_MOUNT_OVERLAY) { | |
86c0dd4a LP |
194 | STRV_FOREACH(j, m->lower) { |
195 | char *s; | |
196 | ||
197 | s = resolve_source_path(dest, *j); | |
198 | if (!s) | |
199 | return log_oom(); | |
200 | ||
10af01a5 | 201 | free_and_replace(*j, s); |
86c0dd4a LP |
202 | } |
203 | ||
d0556c55 LP |
204 | if (m->source) { |
205 | char *s; | |
206 | ||
207 | s = resolve_source_path(dest, m->source); | |
208 | if (!s) | |
209 | return log_oom(); | |
210 | ||
211 | free_and_replace(m->source, s); | |
212 | } else { | |
213 | r = allocate_temporary_source(m); | |
214 | if (r < 0) | |
215 | return r; | |
216 | } | |
217 | ||
86c0dd4a LP |
218 | if (m->work_dir) { |
219 | char *s; | |
220 | ||
221 | s = resolve_source_path(dest, m->work_dir); | |
222 | if (!s) | |
223 | return log_oom(); | |
224 | ||
10af01a5 | 225 | free_and_replace(m->work_dir, s); |
86c0dd4a | 226 | } else { |
86c0dd4a LP |
227 | r = tempfn_random(m->source, NULL, &m->work_dir); |
228 | if (r < 0) | |
229 | return log_error_errno(r, "Failed to acquire working directory: %m"); | |
230 | } | |
231 | ||
232 | (void) mkdir_label(m->work_dir, 0700); | |
233 | } | |
234 | } | |
235 | ||
236 | return 0; | |
237 | } | |
238 | ||
88614c8a | 239 | int bind_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
448f7377 | 240 | _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL, *p = NULL; |
e83bebef LP |
241 | CustomMount *m; |
242 | int r; | |
243 | ||
244 | assert(l); | |
245 | assert(n); | |
246 | ||
a50947c5 | 247 | r = extract_many_words(&s, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); |
e83bebef LP |
248 | if (r < 0) |
249 | return r; | |
250 | if (r == 0) | |
251 | return -EINVAL; | |
e83bebef | 252 | if (r == 1) { |
86c0dd4a | 253 | destination = strdup(source[0] == '+' ? source+1 : source); |
e83bebef LP |
254 | if (!destination) |
255 | return -ENOMEM; | |
256 | } | |
a50947c5 DDM |
257 | if (r == 2 && !isempty(s)) { |
258 | opts = strdup(s); | |
e83bebef LP |
259 | if (!opts) |
260 | return -ENOMEM; | |
261 | } | |
262 | ||
448f7377 DDM |
263 | r = source_path_parse_nullable(source, &p); |
264 | if (r < 0) | |
265 | return r; | |
c7a4890c | 266 | |
e83bebef LP |
267 | if (!path_is_absolute(destination)) |
268 | return -EINVAL; | |
269 | ||
270 | m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); | |
271 | if (!m) | |
48cbe5f8 | 272 | return -ENOMEM; |
e83bebef | 273 | |
448f7377 | 274 | m->source = TAKE_PTR(p); |
0e636bf5 | 275 | m->destination = TAKE_PTR(destination); |
e83bebef | 276 | m->read_only = read_only; |
0e636bf5 | 277 | m->options = TAKE_PTR(opts); |
de40a303 | 278 | |
e83bebef LP |
279 | return 0; |
280 | } | |
281 | ||
88614c8a | 282 | int tmpfs_mount_parse(CustomMount **l, size_t *n, const char *s) { |
e83bebef | 283 | _cleanup_free_ char *path = NULL, *opts = NULL; |
99534007 | 284 | const char *p = ASSERT_PTR(s); |
e83bebef LP |
285 | CustomMount *m; |
286 | int r; | |
287 | ||
288 | assert(l); | |
289 | assert(n); | |
e83bebef LP |
290 | |
291 | r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS); | |
292 | if (r < 0) | |
293 | return r; | |
294 | if (r == 0) | |
295 | return -EINVAL; | |
296 | ||
297 | if (isempty(p)) | |
298 | opts = strdup("mode=0755"); | |
299 | else | |
300 | opts = strdup(p); | |
301 | if (!opts) | |
302 | return -ENOMEM; | |
303 | ||
304 | if (!path_is_absolute(path)) | |
305 | return -EINVAL; | |
306 | ||
307 | m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS); | |
308 | if (!m) | |
309 | return -ENOMEM; | |
310 | ||
1cc6c93a YW |
311 | m->destination = TAKE_PTR(path); |
312 | m->options = TAKE_PTR(opts); | |
e83bebef | 313 | |
e83bebef LP |
314 | return 0; |
315 | } | |
316 | ||
88614c8a | 317 | int overlay_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
ad85779a LP |
318 | _cleanup_free_ char *upper = NULL, *destination = NULL; |
319 | _cleanup_strv_free_ char **lower = NULL; | |
320 | CustomMount *m; | |
448f7377 | 321 | int r, k; |
ad85779a | 322 | |
90e30d76 | 323 | k = strv_split_full(&lower, s, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
86c0dd4a LP |
324 | if (k < 0) |
325 | return k; | |
ad85779a LP |
326 | if (k < 2) |
327 | return -EADDRNOTAVAIL; | |
328 | if (k == 2) { | |
448f7377 DDM |
329 | _cleanup_free_ char *p = NULL; |
330 | ||
86c0dd4a LP |
331 | /* If two parameters are specified, the first one is the lower, the second one the upper directory. And |
332 | * we'll also define the destination mount point the same as the upper. */ | |
333 | ||
448f7377 DDM |
334 | r = source_path_parse(lower[0], &p); |
335 | if (r < 0) | |
336 | return r; | |
337 | ||
338 | free_and_replace(lower[0], p); | |
339 | ||
340 | r = source_path_parse(lower[1], &p); | |
341 | if (r < 0) | |
342 | return r; | |
343 | ||
344 | free_and_replace(lower[1], p); | |
86c0dd4a | 345 | |
ae2a15bc | 346 | upper = TAKE_PTR(lower[1]); |
ad85779a | 347 | |
86c0dd4a | 348 | destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */ |
ad85779a LP |
349 | if (!destination) |
350 | return -ENOMEM; | |
ad85779a | 351 | } else { |
448f7377 DDM |
352 | _cleanup_free_ char *p = NULL; |
353 | ||
86c0dd4a LP |
354 | /* If more than two parameters are specified, the last one is the destination, the second to last one |
355 | * the "upper", and all before that the "lower" directories. */ | |
356 | ||
ad85779a | 357 | destination = lower[k - 1]; |
ae2a15bc | 358 | upper = TAKE_PTR(lower[k - 2]); |
86c0dd4a | 359 | |
448f7377 DDM |
360 | STRV_FOREACH(i, lower) { |
361 | r = source_path_parse(*i, &p); | |
362 | if (r < 0) | |
363 | return r; | |
364 | ||
365 | free_and_replace(*i, p); | |
366 | } | |
c7a4890c LP |
367 | |
368 | /* If the upper directory is unspecified, then let's create it automatically as a throw-away directory | |
369 | * in /var/tmp */ | |
448f7377 DDM |
370 | r = source_path_parse_nullable(upper, &p); |
371 | if (r < 0) | |
372 | return r; | |
373 | ||
374 | free_and_replace(upper, p); | |
c7a4890c | 375 | |
86c0dd4a LP |
376 | if (!path_is_absolute(destination)) |
377 | return -EINVAL; | |
ad85779a LP |
378 | } |
379 | ||
380 | m = custom_mount_add(l, n, CUSTOM_MOUNT_OVERLAY); | |
381 | if (!m) | |
382 | return -ENOMEM; | |
383 | ||
1cc6c93a YW |
384 | m->destination = TAKE_PTR(destination); |
385 | m->source = TAKE_PTR(upper); | |
386 | m->lower = TAKE_PTR(lower); | |
ad85779a LP |
387 | m->read_only = read_only; |
388 | ||
ad85779a LP |
389 | return 0; |
390 | } | |
391 | ||
de40a303 LP |
392 | int inaccessible_mount_parse(CustomMount **l, size_t *n, const char *s) { |
393 | _cleanup_free_ char *path = NULL; | |
394 | CustomMount *m; | |
395 | ||
396 | assert(l); | |
397 | assert(n); | |
398 | assert(s); | |
399 | ||
400 | if (!path_is_absolute(s)) | |
401 | return -EINVAL; | |
402 | ||
403 | path = strdup(s); | |
404 | if (!path) | |
405 | return -ENOMEM; | |
406 | ||
407 | m = custom_mount_add(l, n, CUSTOM_MOUNT_INACCESSIBLE); | |
408 | if (!m) | |
409 | return -ENOMEM; | |
410 | ||
411 | m->destination = TAKE_PTR(path); | |
412 | return 0; | |
413 | } | |
414 | ||
04029482 | 415 | int tmpfs_patch_options( |
e83bebef | 416 | const char *options, |
2fa017f1 | 417 | uid_t uid_shift, |
e83bebef LP |
418 | const char *selinux_apifs_context, |
419 | char **ret) { | |
420 | ||
cfea7618 | 421 | _cleanup_free_ char *buf = NULL; |
e83bebef | 422 | |
cfea7618 | 423 | assert(ret); |
e83bebef | 424 | |
cfea7618 YW |
425 | if (options) { |
426 | buf = strdup(options); | |
427 | if (!buf) | |
428 | return -ENOMEM; | |
e83bebef LP |
429 | } |
430 | ||
cfea7618 YW |
431 | if (uid_shift != UID_INVALID) |
432 | if (strextendf_with_separator(&buf, ",", "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift) < 0) | |
e83bebef | 433 | return -ENOMEM; |
e83bebef | 434 | |
cfea7618 YW |
435 | #if HAVE_SELINUX |
436 | if (selinux_apifs_context) | |
d3d15594 | 437 | if (strextendf_with_separator(&buf, ",", "context=\"%s\"", selinux_apifs_context) < 0) |
0996ef00 | 438 | return -ENOMEM; |
cfea7618 | 439 | #endif |
0996ef00 | 440 | |
cfea7618 YW |
441 | *ret = TAKE_PTR(buf); |
442 | return !!*ret; | |
e83bebef LP |
443 | } |
444 | ||
4f086aab | 445 | int mount_sysfs(const char *dest, MountSettingsMask mount_settings) { |
5980d463 | 446 | const char *full, *top; |
d1678248 | 447 | int r; |
4f086aab | 448 | unsigned long extra_flags = 0; |
d8fc6a00 LP |
449 | |
450 | top = prefix_roota(dest, "/sys"); | |
40fd52f2 | 451 | r = path_is_fs_type(top, SYSFS_MAGIC); |
d1678248 ILG |
452 | if (r < 0) |
453 | return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top); | |
454 | /* /sys might already be mounted as sysfs by the outer child in the | |
455 | * !netns case. In this case, it's all good. Don't touch it because we | |
456 | * don't have the right to do so, see https://github.com/systemd/systemd/issues/1555. | |
457 | */ | |
458 | if (r > 0) | |
459 | return 0; | |
460 | ||
d8fc6a00 LP |
461 | full = prefix_roota(top, "/full"); |
462 | ||
463 | (void) mkdir(full, 0755); | |
464 | ||
bd6609eb | 465 | if (FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO)) |
4f086aab SU |
466 | extra_flags |= MS_RDONLY; |
467 | ||
511a8cfe LP |
468 | r = mount_nofollow_verbose(LOG_ERR, "sysfs", full, "sysfs", |
469 | MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL); | |
60e76d48 ZJS |
470 | if (r < 0) |
471 | return r; | |
d8fc6a00 LP |
472 | |
473 | FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { | |
474 | _cleanup_free_ char *from = NULL, *to = NULL; | |
475 | ||
c6134d3e | 476 | from = path_join(full, x); |
d8fc6a00 LP |
477 | if (!from) |
478 | return log_oom(); | |
479 | ||
c6134d3e | 480 | to = path_join(top, x); |
d8fc6a00 LP |
481 | if (!to) |
482 | return log_oom(); | |
483 | ||
484 | (void) mkdir(to, 0755); | |
485 | ||
511a8cfe | 486 | r = mount_nofollow_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL); |
60e76d48 ZJS |
487 | if (r < 0) |
488 | return r; | |
d8fc6a00 | 489 | |
511a8cfe LP |
490 | r = mount_nofollow_verbose(LOG_ERR, NULL, to, NULL, |
491 | MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); | |
60e76d48 ZJS |
492 | if (r < 0) |
493 | return r; | |
d8fc6a00 LP |
494 | } |
495 | ||
30f5d104 | 496 | r = umount_verbose(LOG_ERR, full, UMOUNT_NOFOLLOW); |
60e76d48 ZJS |
497 | if (r < 0) |
498 | return r; | |
d8fc6a00 LP |
499 | |
500 | if (rmdir(full) < 0) | |
501 | return log_error_errno(errno, "Failed to remove %s: %m", full); | |
502 | ||
0996ef00 CB |
503 | /* Create mountpoint for cgroups. Otherwise we are not allowed since we |
504 | * remount /sys read-only. | |
505 | */ | |
5980d463 | 506 | const char *x = prefix_roota(top, "/fs/cgroup"); |
677a72cd | 507 | (void) mkdir_p(x, 0755); |
d8fc6a00 | 508 | |
511a8cfe LP |
509 | return mount_nofollow_verbose(LOG_ERR, NULL, top, NULL, |
510 | MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); | |
d8fc6a00 LP |
511 | } |
512 | ||
e83bebef | 513 | int mount_all(const char *dest, |
4f086aab | 514 | MountSettingsMask mount_settings, |
2fa017f1 | 515 | uid_t uid_shift, |
e83bebef LP |
516 | const char *selinux_apifs_context) { |
517 | ||
de40a303 LP |
518 | #define PROC_INACCESSIBLE_REG(path) \ |
519 | { "/run/systemd/inaccessible/reg", (path), NULL, NULL, MS_BIND, \ | |
520 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ | |
d4b653c5 LP |
521 | { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ |
522 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ | |
523 | ||
524 | #define PROC_READ_ONLY(path) \ | |
525 | { (path), (path), NULL, NULL, MS_BIND, \ | |
526 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ | |
527 | { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ | |
528 | MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ | |
529 | ||
e83bebef LP |
530 | typedef struct MountPoint { |
531 | const char *what; | |
532 | const char *where; | |
533 | const char *type; | |
534 | const char *options; | |
535 | unsigned long flags; | |
4f086aab | 536 | MountSettingsMask mount_settings; |
e83bebef LP |
537 | } MountPoint; |
538 | ||
539 | static const MountPoint mount_table[] = { | |
d4b653c5 LP |
540 | /* First we list inner child mounts (i.e. mounts applied *after* entering user namespacing) */ |
541 | { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, | |
511a8cfe | 542 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_MKDIR|MOUNT_FOLLOW_SYMLINKS }, /* we follow symlinks here since not following them requires /proc/ already being mounted, which we don't have here. */ |
d4b653c5 LP |
543 | |
544 | { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, | |
545 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ | |
546 | ||
547 | { "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, | |
548 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_APPLY_APIVFS_NETNS }, /* (except for this) */ | |
549 | ||
550 | { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, | |
551 | MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */ | |
552 | ||
553 | /* Make these files inaccessible to container payloads: they potentially leak information about kernel | |
554 | * internals or the host's execution environment to the container */ | |
de40a303 LP |
555 | PROC_INACCESSIBLE_REG("/proc/kallsyms"), |
556 | PROC_INACCESSIBLE_REG("/proc/kcore"), | |
557 | PROC_INACCESSIBLE_REG("/proc/keys"), | |
558 | PROC_INACCESSIBLE_REG("/proc/sysrq-trigger"), | |
559 | PROC_INACCESSIBLE_REG("/proc/timer_list"), | |
d4b653c5 LP |
560 | |
561 | /* Make these directories read-only to container payloads: they show hardware information, and in some | |
562 | * cases contain tunables the container really shouldn't have access to. */ | |
563 | PROC_READ_ONLY("/proc/acpi"), | |
564 | PROC_READ_ONLY("/proc/apm"), | |
565 | PROC_READ_ONLY("/proc/asound"), | |
566 | PROC_READ_ONLY("/proc/bus"), | |
567 | PROC_READ_ONLY("/proc/fs"), | |
568 | PROC_READ_ONLY("/proc/irq"), | |
569 | PROC_READ_ONLY("/proc/scsi"), | |
570 | ||
e1bb4b0d | 571 | { "mqueue", "/dev/mqueue", "mqueue", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
dcff2fa5 | 572 | MOUNT_IN_USERNS|MOUNT_MKDIR }, |
849b9b85 | 573 | |
d4b653c5 | 574 | /* Then we list outer child mounts (i.e. mounts applied *before* entering user namespacing) */ |
b67ec8e5 | 575 | { "tmpfs", "/tmp", "tmpfs", "mode=1777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
dcff2fa5 | 576 | MOUNT_FATAL|MOUNT_APPLY_TMPFS_TMP|MOUNT_MKDIR }, |
e1bb4b0d | 577 | { "tmpfs", "/sys", "tmpfs", "mode=555" TMPFS_LIMITS_SYS, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
dcff2fa5 | 578 | MOUNT_FATAL|MOUNT_APPLY_APIVFS_NETNS|MOUNT_MKDIR }, |
e1bb4b0d | 579 | { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, |
dcff2fa5 | 580 | MOUNT_FATAL|MOUNT_APPLY_APIVFS_RO|MOUNT_MKDIR }, /* skipped if above was mounted */ |
e1bb4b0d | 581 | { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
dcff2fa5 | 582 | MOUNT_FATAL|MOUNT_MKDIR }, /* skipped if above was mounted */ |
570fe6f1 | 583 | { "tmpfs", "/dev", "tmpfs", "mode=755" TMPFS_LIMITS_PRIVATE_DEV, MS_NOSUID|MS_STRICTATIME, |
dcff2fa5 | 584 | MOUNT_FATAL|MOUNT_MKDIR }, |
b67ec8e5 | 585 | { "tmpfs", "/dev/shm", "tmpfs", "mode=1777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
dcff2fa5 | 586 | MOUNT_FATAL|MOUNT_MKDIR }, |
e1bb4b0d | 587 | { "tmpfs", "/run", "tmpfs", "mode=755" TMPFS_LIMITS_RUN, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
dcff2fa5 | 588 | MOUNT_FATAL|MOUNT_MKDIR }, |
d64e32c2 LP |
589 | { "/run/host", "/run/host", NULL, NULL, MS_BIND, |
590 | MOUNT_FATAL|MOUNT_MKDIR|MOUNT_PREFIX_ROOT }, /* Prepare this so that we can make it read-only when we are done */ | |
591 | { "/etc/os-release", "/run/host/os-release", NULL, NULL, MS_BIND, | |
592 | MOUNT_TOUCH }, /* As per kernel interface requirements, bind mount first (creating mount points) and make read-only later */ | |
593 | { "/usr/lib/os-release", "/run/host/os-release", NULL, NULL, MS_BIND, | |
594 | MOUNT_FATAL }, /* If /etc/os-release doesn't exist use the version in /usr/lib as fallback */ | |
595 | { NULL, "/run/host/os-release", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, | |
596 | MOUNT_FATAL }, | |
597 | { NULL, "/run/host", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, | |
598 | MOUNT_FATAL|MOUNT_IN_USERNS }, | |
349cc4a5 | 599 | #if HAVE_SELINUX |
e1bb4b0d | 600 | { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, |
6fe01ced | 601 | MOUNT_MKDIR }, /* Bind mount first (mkdir/chown the mount point in case /sys/ is mounted as minimal skeleton tmpfs) */ |
e1bb4b0d | 602 | { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, |
6fe01ced | 603 | 0 }, /* Then, make it r/o (don't mkdir/chown the mount point here, the previous entry already did that) */ |
e83bebef LP |
604 | #endif |
605 | }; | |
606 | ||
bd6609eb DDM |
607 | bool use_userns = FLAGS_SET(mount_settings, MOUNT_USE_USERNS); |
608 | bool netns = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_NETNS); | |
609 | bool ro = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO); | |
610 | bool in_userns = FLAGS_SET(mount_settings, MOUNT_IN_USERNS); | |
611 | bool tmpfs_tmp = FLAGS_SET(mount_settings, MOUNT_APPLY_TMPFS_TMP); | |
88614c8a | 612 | int r; |
e83bebef | 613 | |
d2b99ed7 | 614 | for (size_t k = 0; k < ELEMENTSOF(mount_table); k++) { |
d64e32c2 | 615 | _cleanup_free_ char *where = NULL, *options = NULL, *prefixed = NULL; |
bd6609eb | 616 | bool fatal = FLAGS_SET(mount_table[k].mount_settings, MOUNT_FATAL); |
d64e32c2 | 617 | const char *o; |
4f086aab | 618 | |
bd6609eb | 619 | if (in_userns != FLAGS_SET(mount_table[k].mount_settings, MOUNT_IN_USERNS)) |
4f086aab | 620 | continue; |
e83bebef | 621 | |
bd6609eb | 622 | if (!netns && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_APIVFS_NETNS)) |
d1678248 ILG |
623 | continue; |
624 | ||
bd6609eb | 625 | if (!ro && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_APIVFS_RO)) |
e83bebef LP |
626 | continue; |
627 | ||
bd6609eb | 628 | if (!tmpfs_tmp && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_TMPFS_TMP)) |
1099ceeb LP |
629 | continue; |
630 | ||
a5648b80 | 631 | r = chase_symlinks(mount_table[k].where, dest, CHASE_NONEXISTENT|CHASE_PREFIX_ROOT, &where, NULL); |
8ce48cf0 | 632 | if (r < 0) |
ec57bd42 | 633 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].where); |
e83bebef | 634 | |
e83bebef | 635 | /* Skip this entry if it is not a remount. */ |
de40a303 LP |
636 | if (mount_table[k].what) { |
637 | r = path_is_mount_point(where, NULL, 0); | |
638 | if (r < 0 && r != -ENOENT) | |
639 | return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); | |
640 | if (r > 0) | |
641 | continue; | |
642 | } | |
e83bebef | 643 | |
d64e32c2 | 644 | if ((mount_table[k].mount_settings & (MOUNT_MKDIR|MOUNT_TOUCH)) != 0) { |
b3b1a08a | 645 | uid_t u = (use_userns && !in_userns) ? uid_shift : UID_INVALID; |
e1bb4b0d LB |
646 | |
647 | if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_TOUCH)) | |
648 | r = mkdir_parents_safe(dest, where, 0755, u, u, 0); | |
649 | else | |
650 | r = mkdir_p_safe(dest, where, 0755, u, u, 0); | |
dcff2fa5 LP |
651 | if (r < 0 && r != -EEXIST) { |
652 | if (fatal && r != -EROFS) | |
653 | return log_error_errno(r, "Failed to create directory %s: %m", where); | |
e83bebef | 654 | |
dcff2fa5 LP |
655 | log_debug_errno(r, "Failed to create directory %s: %m", where); |
656 | ||
657 | /* If we failed mkdir() or chown() due to the root directory being read only, | |
658 | * attempt to mount this fs anyway and let mount_verbose log any errors */ | |
659 | if (r != -EROFS) | |
660 | continue; | |
661 | } | |
d64e32c2 LP |
662 | } |
663 | ||
664 | if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_TOUCH)) { | |
665 | r = touch(where); | |
666 | if (r < 0 && r != -EEXIST) { | |
667 | if (fatal && r != -EROFS) | |
668 | return log_error_errno(r, "Failed to create file %s: %m", where); | |
669 | ||
670 | log_debug_errno(r, "Failed to create file %s: %m", where); | |
671 | if (r != -EROFS) | |
672 | continue; | |
e1bb4b0d | 673 | } |
e83bebef LP |
674 | } |
675 | ||
676 | o = mount_table[k].options; | |
677 | if (streq_ptr(mount_table[k].type, "tmpfs")) { | |
2fa017f1 | 678 | r = tmpfs_patch_options(o, in_userns ? 0 : uid_shift, selinux_apifs_context, &options); |
e83bebef LP |
679 | if (r < 0) |
680 | return log_oom(); | |
681 | if (r > 0) | |
682 | o = options; | |
683 | } | |
684 | ||
d64e32c2 LP |
685 | if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_PREFIX_ROOT)) { |
686 | /* Optionally prefix the mount source with the root dir. This is useful in bind | |
687 | * mounts to be created within the container image before we transition into it. Note | |
688 | * that MOUNT_IN_USERNS is run after we transitioned hence prefixing is not ncessary | |
689 | * for those. */ | |
690 | r = chase_symlinks(mount_table[k].what, dest, CHASE_PREFIX_ROOT, &prefixed, NULL); | |
691 | if (r < 0) | |
692 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].what); | |
693 | } | |
694 | ||
511a8cfe LP |
695 | r = mount_verbose_full( |
696 | fatal ? LOG_ERR : LOG_DEBUG, | |
697 | prefixed ?: mount_table[k].what, | |
698 | where, | |
699 | mount_table[k].type, | |
700 | mount_table[k].flags, | |
701 | o, | |
702 | FLAGS_SET(mount_table[k].mount_settings, MOUNT_FOLLOW_SYMLINKS)); | |
4f086aab | 703 | if (r < 0 && fatal) |
60e76d48 | 704 | return r; |
e83bebef LP |
705 | } |
706 | ||
707 | return 0; | |
708 | } | |
709 | ||
1aa18710 | 710 | static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts, RemountIdmapping *idmapping) { |
a11fd406 ILG |
711 | unsigned long flags = *mount_flags; |
712 | char *opts = NULL; | |
1aa18710 | 713 | RemountIdmapping new_idmapping = *idmapping; |
a11fd406 ILG |
714 | int r; |
715 | ||
716 | assert(options); | |
717 | ||
718 | for (;;) { | |
719 | _cleanup_free_ char *word = NULL; | |
720 | ||
d2b99ed7 | 721 | r = extract_first_word(&options, &word, ",", 0); |
a11fd406 ILG |
722 | if (r < 0) |
723 | return log_error_errno(r, "Failed to extract mount option: %m"); | |
724 | if (r == 0) | |
725 | break; | |
726 | ||
727 | if (streq(word, "rbind")) | |
728 | flags |= MS_REC; | |
729 | else if (streq(word, "norbind")) | |
730 | flags &= ~MS_REC; | |
c0c8f718 | 731 | else if (streq(word, "idmap")) |
1aa18710 | 732 | new_idmapping = REMOUNT_IDMAPPING_HOST_ROOT; |
c0c8f718 | 733 | else if (streq(word, "noidmap")) |
1aa18710 | 734 | new_idmapping = REMOUNT_IDMAPPING_NONE; |
2b2777ed QD |
735 | else if (streq(word, "rootidmap")) |
736 | new_idmapping = REMOUNT_IDMAPPING_HOST_OWNER; | |
d2b99ed7 | 737 | else |
38288f0b | 738 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
d2b99ed7 | 739 | "Invalid bind mount option: %s", word); |
a11fd406 ILG |
740 | } |
741 | ||
742 | *mount_flags = flags; | |
1aa18710 | 743 | *idmapping = new_idmapping; |
a11fd406 ILG |
744 | /* in the future mount_opts will hold string options for mount(2) */ |
745 | *mount_opts = opts; | |
746 | ||
747 | return 0; | |
748 | } | |
749 | ||
c0c8f718 | 750 | static int mount_bind(const char *dest, CustomMount *m, uid_t uid_shift, uid_t uid_range) { |
a11fd406 ILG |
751 | _cleanup_free_ char *mount_opts = NULL, *where = NULL; |
752 | unsigned long mount_flags = MS_BIND | MS_REC; | |
68cf43c3 | 753 | struct stat source_st, dest_st; |
e83bebef | 754 | int r; |
1aa18710 | 755 | RemountIdmapping idmapping = REMOUNT_IDMAPPING_NONE; |
e83bebef | 756 | |
86c0dd4a | 757 | assert(dest); |
e83bebef LP |
758 | assert(m); |
759 | ||
a11fd406 | 760 | if (m->options) { |
1aa18710 | 761 | r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts, &idmapping); |
a11fd406 ILG |
762 | if (r < 0) |
763 | return r; | |
764 | } | |
765 | ||
07bca16f LP |
766 | /* If this is a bind mount from a temporary sources change ownership of the source to the container's |
767 | * root UID. Otherwise it would always show up as "nobody" if user namespacing is used. */ | |
768 | if (m->rm_rf_tmpdir && chown(m->source, uid_shift, uid_shift) < 0) | |
769 | return log_error_errno(errno, "Failed to chown %s: %m", m->source); | |
770 | ||
e83bebef LP |
771 | if (stat(m->source, &source_st) < 0) |
772 | return log_error_errno(errno, "Failed to stat %s: %m", m->source); | |
773 | ||
a5648b80 | 774 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
68cf43c3 | 775 | if (r < 0) |
ec57bd42 | 776 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
777 | if (r > 0) { /* Path exists already? */ |
778 | ||
779 | if (stat(where, &dest_st) < 0) | |
780 | return log_error_errno(errno, "Failed to stat %s: %m", where); | |
e83bebef | 781 | |
baaa35ad ZJS |
782 | if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) |
783 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), | |
784 | "Cannot bind mount directory %s on file %s.", | |
785 | m->source, where); | |
786 | ||
787 | if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) | |
788 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), | |
789 | "Cannot bind mount file %s on directory %s.", | |
790 | m->source, where); | |
e83bebef | 791 | |
8ce48cf0 | 792 | } else { /* Path doesn't exist yet? */ |
e83bebef LP |
793 | r = mkdir_parents_label(where, 0755); |
794 | if (r < 0) | |
795 | return log_error_errno(r, "Failed to make parents of %s: %m", where); | |
b97e83cb BN |
796 | |
797 | /* Create the mount point. Any non-directory file can be | |
798 | * mounted on any non-directory file (regular, fifo, socket, | |
799 | * char, block). | |
800 | */ | |
801 | if (S_ISDIR(source_st.st_mode)) | |
802 | r = mkdir_label(where, 0755); | |
803 | else | |
804 | r = touch(where); | |
805 | if (r < 0) | |
806 | return log_error_errno(r, "Failed to create mount point %s: %m", where); | |
8ce48cf0 | 807 | } |
e83bebef | 808 | |
511a8cfe | 809 | r = mount_nofollow_verbose(LOG_ERR, m->source, where, NULL, mount_flags, mount_opts); |
60e76d48 ZJS |
810 | if (r < 0) |
811 | return r; | |
e83bebef LP |
812 | |
813 | if (m->read_only) { | |
64e82c19 | 814 | r = bind_remount_recursive(where, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
815 | if (r < 0) |
816 | return log_error_errno(r, "Read-only bind mount failed: %m"); | |
817 | } | |
818 | ||
1aa18710 | 819 | if (idmapping != REMOUNT_IDMAPPING_NONE) { |
2b2777ed | 820 | r = remount_idmap(where, uid_shift, uid_range, source_st.st_uid, idmapping); |
c0c8f718 AV |
821 | if (r < 0) |
822 | return log_error_errno(r, "Failed to map ids for bind mount %s: %m", where); | |
823 | } | |
824 | ||
e83bebef LP |
825 | return 0; |
826 | } | |
827 | ||
e091a5df | 828 | static int mount_tmpfs(const char *dest, CustomMount *m, uid_t uid_shift, const char *selinux_apifs_context) { |
68cf43c3 LP |
829 | const char *options; |
830 | _cleanup_free_ char *buf = NULL, *where = NULL; | |
e83bebef LP |
831 | int r; |
832 | ||
833 | assert(dest); | |
834 | assert(m); | |
835 | ||
a5648b80 | 836 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
68cf43c3 | 837 | if (r < 0) |
ec57bd42 | 838 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
839 | if (r == 0) { /* Doesn't exist yet? */ |
840 | r = mkdir_p_label(where, 0755); | |
841 | if (r < 0) | |
842 | return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); | |
843 | } | |
e83bebef | 844 | |
2fa017f1 | 845 | r = tmpfs_patch_options(m->options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef LP |
846 | if (r < 0) |
847 | return log_oom(); | |
848 | options = r > 0 ? buf : m->options; | |
849 | ||
511a8cfe | 850 | return mount_nofollow_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options); |
e83bebef LP |
851 | } |
852 | ||
86c0dd4a | 853 | static char *joined_and_escaped_lower_dirs(char **lower) { |
e83bebef LP |
854 | _cleanup_strv_free_ char **sv = NULL; |
855 | ||
856 | sv = strv_copy(lower); | |
857 | if (!sv) | |
858 | return NULL; | |
859 | ||
860 | strv_reverse(sv); | |
861 | ||
862 | if (!strv_shell_escape(sv, ",:")) | |
863 | return NULL; | |
864 | ||
865 | return strv_join(sv, ":"); | |
866 | } | |
867 | ||
868 | static int mount_overlay(const char *dest, CustomMount *m) { | |
86c0dd4a | 869 | _cleanup_free_ char *lower = NULL, *where = NULL, *escaped_source = NULL; |
68cf43c3 | 870 | const char *options; |
e83bebef LP |
871 | int r; |
872 | ||
873 | assert(dest); | |
874 | assert(m); | |
875 | ||
a5648b80 | 876 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
68cf43c3 | 877 | if (r < 0) |
ec57bd42 | 878 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
8ce48cf0 LP |
879 | if (r == 0) { /* Doesn't exist yet? */ |
880 | r = mkdir_label(where, 0755); | |
881 | if (r < 0) | |
882 | return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where); | |
883 | } | |
e83bebef LP |
884 | |
885 | (void) mkdir_p_label(m->source, 0755); | |
886 | ||
887 | lower = joined_and_escaped_lower_dirs(m->lower); | |
888 | if (!lower) | |
889 | return log_oom(); | |
890 | ||
86c0dd4a LP |
891 | escaped_source = shell_escape(m->source, ",:"); |
892 | if (!escaped_source) | |
893 | return log_oom(); | |
e83bebef | 894 | |
86c0dd4a | 895 | if (m->read_only) |
e83bebef | 896 | options = strjoina("lowerdir=", escaped_source, ":", lower); |
86c0dd4a LP |
897 | else { |
898 | _cleanup_free_ char *escaped_work_dir = NULL; | |
e83bebef | 899 | |
e83bebef LP |
900 | escaped_work_dir = shell_escape(m->work_dir, ",:"); |
901 | if (!escaped_work_dir) | |
902 | return log_oom(); | |
903 | ||
904 | options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir); | |
905 | } | |
906 | ||
511a8cfe | 907 | return mount_nofollow_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options); |
e83bebef LP |
908 | } |
909 | ||
de40a303 | 910 | static int mount_inaccessible(const char *dest, CustomMount *m) { |
e5f10caf | 911 | _cleanup_free_ char *where = NULL, *source = NULL; |
de40a303 LP |
912 | struct stat st; |
913 | int r; | |
914 | ||
915 | assert(dest); | |
916 | assert(m); | |
917 | ||
a5648b80 | 918 | r = chase_symlinks_and_stat(m->destination, dest, CHASE_PREFIX_ROOT, &where, &st, NULL); |
de40a303 LP |
919 | if (r < 0) { |
920 | log_full_errno(m->graceful ? LOG_DEBUG : LOG_ERR, r, "Failed to resolve %s/%s: %m", dest, m->destination); | |
921 | return m->graceful ? 0 : r; | |
922 | } | |
923 | ||
48b747fa | 924 | r = mode_to_inaccessible_node(NULL, st.st_mode, &source); |
e5f10caf AZ |
925 | if (r < 0) |
926 | return m->graceful ? 0 : r; | |
de40a303 | 927 | |
511a8cfe | 928 | r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, source, where, NULL, MS_BIND, NULL); |
de40a303 LP |
929 | if (r < 0) |
930 | return m->graceful ? 0 : r; | |
931 | ||
511a8cfe | 932 | r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, NULL, where, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL); |
2c9b7a7e | 933 | if (r < 0) { |
30f5d104 | 934 | (void) umount_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, where, UMOUNT_NOFOLLOW); |
de40a303 | 935 | return m->graceful ? 0 : r; |
2c9b7a7e | 936 | } |
de40a303 LP |
937 | |
938 | return 0; | |
939 | } | |
940 | ||
941 | static int mount_arbitrary(const char *dest, CustomMount *m) { | |
942 | _cleanup_free_ char *where = NULL; | |
943 | int r; | |
944 | ||
945 | assert(dest); | |
946 | assert(m); | |
947 | ||
a5648b80 | 948 | r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
de40a303 LP |
949 | if (r < 0) |
950 | return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); | |
951 | if (r == 0) { /* Doesn't exist yet? */ | |
952 | r = mkdir_p_label(where, 0755); | |
953 | if (r < 0) | |
954 | return log_error_errno(r, "Creating mount point for mount %s failed: %m", where); | |
955 | } | |
956 | ||
511a8cfe | 957 | return mount_nofollow_verbose(LOG_ERR, m->source, where, m->type_argument, 0, m->options); |
de40a303 LP |
958 | } |
959 | ||
e83bebef LP |
960 | int mount_custom( |
961 | const char *dest, | |
88614c8a | 962 | CustomMount *mounts, size_t n, |
e091a5df | 963 | uid_t uid_shift, |
c0c8f718 | 964 | uid_t uid_range, |
de40a303 | 965 | const char *selinux_apifs_context, |
5f0a6347 | 966 | MountSettingsMask mount_settings) { |
e83bebef LP |
967 | int r; |
968 | ||
969 | assert(dest); | |
970 | ||
d2b99ed7 | 971 | for (size_t i = 0; i < n; i++) { |
e83bebef LP |
972 | CustomMount *m = mounts + i; |
973 | ||
bd6609eb | 974 | if (FLAGS_SET(mount_settings, MOUNT_IN_USERNS) != m->in_userns) |
5f0a6347 DDM |
975 | continue; |
976 | ||
bd6609eb | 977 | if (FLAGS_SET(mount_settings, MOUNT_ROOT_ONLY) && !path_equal(m->destination, "/")) |
5f0a6347 DDM |
978 | continue; |
979 | ||
bd6609eb | 980 | if (FLAGS_SET(mount_settings, MOUNT_NON_ROOT_ONLY) && path_equal(m->destination, "/")) |
de40a303 LP |
981 | continue; |
982 | ||
e83bebef LP |
983 | switch (m->type) { |
984 | ||
985 | case CUSTOM_MOUNT_BIND: | |
c0c8f718 | 986 | r = mount_bind(dest, m, uid_shift, uid_range); |
e83bebef LP |
987 | break; |
988 | ||
989 | case CUSTOM_MOUNT_TMPFS: | |
e091a5df | 990 | r = mount_tmpfs(dest, m, uid_shift, selinux_apifs_context); |
e83bebef LP |
991 | break; |
992 | ||
993 | case CUSTOM_MOUNT_OVERLAY: | |
994 | r = mount_overlay(dest, m); | |
995 | break; | |
996 | ||
de40a303 LP |
997 | case CUSTOM_MOUNT_INACCESSIBLE: |
998 | r = mount_inaccessible(dest, m); | |
999 | break; | |
1000 | ||
1001 | case CUSTOM_MOUNT_ARBITRARY: | |
1002 | r = mount_arbitrary(dest, m); | |
1003 | break; | |
1004 | ||
e83bebef | 1005 | default: |
04499a70 | 1006 | assert_not_reached(); |
e83bebef LP |
1007 | } |
1008 | ||
1009 | if (r < 0) | |
1010 | return r; | |
1011 | } | |
1012 | ||
1013 | return 0; | |
1014 | } | |
1015 | ||
bbd407ea | 1016 | bool has_custom_root_mount(const CustomMount *mounts, size_t n) { |
d2b99ed7 ZJS |
1017 | for (size_t i = 0; i < n; i++) |
1018 | if (path_equal(mounts[i].destination, "/")) | |
bbd407ea | 1019 | return true; |
bbd407ea DDM |
1020 | |
1021 | return false; | |
1022 | } | |
1023 | ||
e091a5df | 1024 | static int setup_volatile_state(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
e83bebef LP |
1025 | _cleanup_free_ char *buf = NULL; |
1026 | const char *p, *options; | |
1027 | int r; | |
1028 | ||
1029 | assert(directory); | |
1030 | ||
e5b43a04 | 1031 | /* --volatile=state means we simply overmount /var with a tmpfs, and the rest read-only. */ |
e83bebef | 1032 | |
64e82c19 | 1033 | r = bind_remount_recursive(directory, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
1034 | if (r < 0) |
1035 | return log_error_errno(r, "Failed to remount %s read-only: %m", directory); | |
1036 | ||
1037 | p = prefix_roota(directory, "/var"); | |
1038 | r = mkdir(p, 0755); | |
1039 | if (r < 0 && errno != EEXIST) | |
1040 | return log_error_errno(errno, "Failed to create %s: %m", directory); | |
1041 | ||
7d85383e | 1042 | options = "mode=755" TMPFS_LIMITS_VOLATILE_STATE; |
2fa017f1 | 1043 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef LP |
1044 | if (r < 0) |
1045 | return log_oom(); | |
1046 | if (r > 0) | |
1047 | options = buf; | |
1048 | ||
511a8cfe | 1049 | return mount_nofollow_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options); |
e83bebef LP |
1050 | } |
1051 | ||
e091a5df | 1052 | static int setup_volatile_yes(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
e83bebef LP |
1053 | bool tmpfs_mounted = false, bind_mounted = false; |
1054 | char template[] = "/tmp/nspawn-volatile-XXXXXX"; | |
07b9f3f0 | 1055 | _cleanup_free_ char *buf = NULL, *bindir = NULL; |
e83bebef | 1056 | const char *f, *t, *options; |
07b9f3f0 | 1057 | struct stat st; |
e83bebef LP |
1058 | int r; |
1059 | ||
1060 | assert(directory); | |
1061 | ||
07b9f3f0 LP |
1062 | /* --volatile=yes means we mount a tmpfs to the root dir, and the original /usr to use inside it, and |
1063 | * that read-only. Before we start setting this up let's validate if the image has the /usr merge | |
1064 | * implemented, and let's output a friendly log message if it hasn't. */ | |
1065 | ||
1066 | bindir = path_join(directory, "/bin"); | |
1067 | if (!bindir) | |
1068 | return log_oom(); | |
1069 | if (lstat(bindir, &st) < 0) { | |
1070 | if (errno != ENOENT) | |
1071 | return log_error_errno(errno, "Failed to stat /bin directory below image: %m"); | |
1072 | ||
1073 | /* ENOENT is fine, just means the image is probably just a naked /usr and we can create the | |
1074 | * rest. */ | |
1075 | } else if (S_ISDIR(st.st_mode)) | |
1076 | return log_error_errno(SYNTHETIC_ERRNO(EISDIR), | |
1077 | "Sorry, --volatile=yes mode is not supported with OS images that have not merged /bin/, /sbin/, /lib/, /lib64/ into /usr/. " | |
1078 | "Please work with your distribution and help them adopt the merged /usr scheme."); | |
1079 | else if (!S_ISLNK(st.st_mode)) | |
1080 | return log_error_errno(SYNTHETIC_ERRNO(EINVAL), | |
1081 | "Error starting image: if --volatile=yes is used /bin must be a symlink (for merged /usr support) or non-existent (in which case a symlink is created automatically)."); | |
e83bebef LP |
1082 | |
1083 | if (!mkdtemp(template)) | |
1084 | return log_error_errno(errno, "Failed to create temporary directory: %m"); | |
1085 | ||
7d85383e | 1086 | options = "mode=755" TMPFS_LIMITS_ROOTFS; |
2fa017f1 | 1087 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
e83bebef | 1088 | if (r < 0) |
c55d0ae7 | 1089 | goto fail; |
e83bebef LP |
1090 | if (r > 0) |
1091 | options = buf; | |
1092 | ||
511a8cfe | 1093 | r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); |
60e76d48 | 1094 | if (r < 0) |
e83bebef | 1095 | goto fail; |
e83bebef LP |
1096 | |
1097 | tmpfs_mounted = true; | |
1098 | ||
1099 | f = prefix_roota(directory, "/usr"); | |
1100 | t = prefix_roota(template, "/usr"); | |
1101 | ||
1102 | r = mkdir(t, 0755); | |
1103 | if (r < 0 && errno != EEXIST) { | |
1104 | r = log_error_errno(errno, "Failed to create %s: %m", t); | |
1105 | goto fail; | |
1106 | } | |
1107 | ||
511a8cfe | 1108 | r = mount_nofollow_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL); |
60e76d48 | 1109 | if (r < 0) |
e83bebef | 1110 | goto fail; |
e83bebef LP |
1111 | |
1112 | bind_mounted = true; | |
1113 | ||
64e82c19 | 1114 | r = bind_remount_recursive(t, MS_RDONLY, MS_RDONLY, NULL); |
e83bebef LP |
1115 | if (r < 0) { |
1116 | log_error_errno(r, "Failed to remount %s read-only: %m", t); | |
1117 | goto fail; | |
1118 | } | |
1119 | ||
511a8cfe | 1120 | r = mount_nofollow_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL); |
60e76d48 | 1121 | if (r < 0) |
e83bebef | 1122 | goto fail; |
e83bebef LP |
1123 | |
1124 | (void) rmdir(template); | |
1125 | ||
1126 | return 0; | |
1127 | ||
1128 | fail: | |
1129 | if (bind_mounted) | |
30f5d104 | 1130 | (void) umount_verbose(LOG_ERR, t, UMOUNT_NOFOLLOW); |
e83bebef LP |
1131 | |
1132 | if (tmpfs_mounted) | |
30f5d104 LP |
1133 | (void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW); |
1134 | ||
e83bebef LP |
1135 | (void) rmdir(template); |
1136 | return r; | |
1137 | } | |
b53ede69 | 1138 | |
e091a5df | 1139 | static int setup_volatile_overlay(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
6c610aca LP |
1140 | _cleanup_free_ char *buf = NULL, *escaped_directory = NULL, *escaped_upper = NULL, *escaped_work = NULL; |
1141 | char template[] = "/tmp/nspawn-volatile-XXXXXX"; | |
1142 | const char *upper, *work, *options; | |
1143 | bool tmpfs_mounted = false; | |
1144 | int r; | |
1145 | ||
1146 | assert(directory); | |
1147 | ||
1148 | /* --volatile=overlay means we mount an overlayfs to the root dir. */ | |
1149 | ||
1150 | if (!mkdtemp(template)) | |
1151 | return log_error_errno(errno, "Failed to create temporary directory: %m"); | |
1152 | ||
7d85383e | 1153 | options = "mode=755" TMPFS_LIMITS_ROOTFS; |
6c610aca LP |
1154 | r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
1155 | if (r < 0) | |
1156 | goto finish; | |
1157 | if (r > 0) | |
1158 | options = buf; | |
1159 | ||
511a8cfe | 1160 | r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); |
6c610aca LP |
1161 | if (r < 0) |
1162 | goto finish; | |
1163 | ||
1164 | tmpfs_mounted = true; | |
1165 | ||
1166 | upper = strjoina(template, "/upper"); | |
1167 | work = strjoina(template, "/work"); | |
1168 | ||
1169 | if (mkdir(upper, 0755) < 0) { | |
1170 | r = log_error_errno(errno, "Failed to create %s: %m", upper); | |
1171 | goto finish; | |
1172 | } | |
1173 | if (mkdir(work, 0755) < 0) { | |
1174 | r = log_error_errno(errno, "Failed to create %s: %m", work); | |
1175 | goto finish; | |
1176 | } | |
1177 | ||
1178 | /* And now, let's overmount the root dir with an overlayfs that uses the root dir as lower dir. It's kinda nice | |
1179 | * that the kernel allows us to do that without going through some mount point rearrangements. */ | |
1180 | ||
1181 | escaped_directory = shell_escape(directory, ",:"); | |
1182 | escaped_upper = shell_escape(upper, ",:"); | |
1183 | escaped_work = shell_escape(work, ",:"); | |
1184 | if (!escaped_directory || !escaped_upper || !escaped_work) { | |
1185 | r = -ENOMEM; | |
1186 | goto finish; | |
1187 | } | |
1188 | ||
1189 | options = strjoina("lowerdir=", escaped_directory, ",upperdir=", escaped_upper, ",workdir=", escaped_work); | |
511a8cfe | 1190 | r = mount_nofollow_verbose(LOG_ERR, "overlay", directory, "overlay", 0, options); |
6c610aca LP |
1191 | |
1192 | finish: | |
1193 | if (tmpfs_mounted) | |
30f5d104 | 1194 | (void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW); |
6c610aca LP |
1195 | |
1196 | (void) rmdir(template); | |
1197 | return r; | |
1198 | } | |
1199 | ||
e5b43a04 LP |
1200 | int setup_volatile_mode( |
1201 | const char *directory, | |
1202 | VolatileMode mode, | |
e091a5df | 1203 | uid_t uid_shift, |
e5b43a04 LP |
1204 | const char *selinux_apifs_context) { |
1205 | ||
1206 | switch (mode) { | |
1207 | ||
1208 | case VOLATILE_YES: | |
e091a5df | 1209 | return setup_volatile_yes(directory, uid_shift, selinux_apifs_context); |
e5b43a04 LP |
1210 | |
1211 | case VOLATILE_STATE: | |
e091a5df | 1212 | return setup_volatile_state(directory, uid_shift, selinux_apifs_context); |
e5b43a04 | 1213 | |
6c610aca | 1214 | case VOLATILE_OVERLAY: |
e091a5df | 1215 | return setup_volatile_overlay(directory, uid_shift, selinux_apifs_context); |
6c610aca | 1216 | |
e5b43a04 LP |
1217 | default: |
1218 | return 0; | |
1219 | } | |
1220 | } | |
1221 | ||
b53ede69 PW |
1222 | /* Expects *pivot_root_new and *pivot_root_old to be initialised to allocated memory or NULL. */ |
1223 | int pivot_root_parse(char **pivot_root_new, char **pivot_root_old, const char *s) { | |
1224 | _cleanup_free_ char *root_new = NULL, *root_old = NULL; | |
1225 | const char *p = s; | |
1226 | int r; | |
1227 | ||
1228 | assert(pivot_root_new); | |
1229 | assert(pivot_root_old); | |
1230 | ||
1231 | r = extract_first_word(&p, &root_new, ":", EXTRACT_DONT_COALESCE_SEPARATORS); | |
1232 | if (r < 0) | |
1233 | return r; | |
1234 | if (r == 0) | |
1235 | return -EINVAL; | |
1236 | ||
1237 | if (isempty(p)) | |
1238 | root_old = NULL; | |
1239 | else { | |
1240 | root_old = strdup(p); | |
1241 | if (!root_old) | |
1242 | return -ENOMEM; | |
1243 | } | |
1244 | ||
1245 | if (!path_is_absolute(root_new)) | |
1246 | return -EINVAL; | |
1247 | if (root_old && !path_is_absolute(root_old)) | |
1248 | return -EINVAL; | |
1249 | ||
1250 | free_and_replace(*pivot_root_new, root_new); | |
1251 | free_and_replace(*pivot_root_old, root_old); | |
1252 | ||
1253 | return 0; | |
1254 | } | |
1255 | ||
1256 | int setup_pivot_root(const char *directory, const char *pivot_root_new, const char *pivot_root_old) { | |
1257 | _cleanup_free_ char *directory_pivot_root_new = NULL; | |
1258 | _cleanup_free_ char *pivot_tmp_pivot_root_old = NULL; | |
1259 | char pivot_tmp[] = "/tmp/nspawn-pivot-XXXXXX"; | |
1260 | bool remove_pivot_tmp = false; | |
1261 | int r; | |
1262 | ||
1263 | assert(directory); | |
1264 | ||
1265 | if (!pivot_root_new) | |
1266 | return 0; | |
1267 | ||
1268 | /* Pivot pivot_root_new to / and the existing / to pivot_root_old. | |
1269 | * If pivot_root_old is NULL, the existing / disappears. | |
1270 | * This requires a temporary directory, pivot_tmp, which is | |
1271 | * not a child of either. | |
1272 | * | |
1273 | * This is typically used for OSTree-style containers, where | |
1274 | * the root partition contains several sysroots which could be | |
1275 | * run. Normally, one would be chosen by the bootloader and | |
1276 | * pivoted to / by initramfs. | |
1277 | * | |
1278 | * For example, for an OSTree deployment, pivot_root_new | |
1279 | * would be: /ostree/deploy/$os/deploy/$checksum. Note that this | |
1280 | * code doesn’t do the /var mount which OSTree expects: use | |
1281 | * --bind +/sysroot/ostree/deploy/$os/var:/var for that. | |
1282 | * | |
1283 | * So in the OSTree case, we’ll end up with something like: | |
1284 | * - directory = /tmp/nspawn-root-123456 | |
1285 | * - pivot_root_new = /ostree/deploy/os/deploy/123abc | |
1286 | * - pivot_root_old = /sysroot | |
1287 | * - directory_pivot_root_new = | |
1288 | * /tmp/nspawn-root-123456/ostree/deploy/os/deploy/123abc | |
1289 | * - pivot_tmp = /tmp/nspawn-pivot-123456 | |
1290 | * - pivot_tmp_pivot_root_old = /tmp/nspawn-pivot-123456/sysroot | |
1291 | * | |
1292 | * Requires all file systems at directory and below to be mounted | |
1293 | * MS_PRIVATE or MS_SLAVE so they can be moved. | |
1294 | */ | |
c6134d3e LP |
1295 | directory_pivot_root_new = path_join(directory, pivot_root_new); |
1296 | if (!directory_pivot_root_new) | |
1297 | return log_oom(); | |
b53ede69 PW |
1298 | |
1299 | /* Remount directory_pivot_root_new to make it movable. */ | |
511a8cfe | 1300 | r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory_pivot_root_new, NULL, MS_BIND, NULL); |
b53ede69 PW |
1301 | if (r < 0) |
1302 | goto done; | |
1303 | ||
1304 | if (pivot_root_old) { | |
1305 | if (!mkdtemp(pivot_tmp)) { | |
1306 | r = log_error_errno(errno, "Failed to create temporary directory: %m"); | |
1307 | goto done; | |
1308 | } | |
1309 | ||
1310 | remove_pivot_tmp = true; | |
c6134d3e LP |
1311 | pivot_tmp_pivot_root_old = path_join(pivot_tmp, pivot_root_old); |
1312 | if (!pivot_tmp_pivot_root_old) { | |
1313 | r = log_oom(); | |
1314 | goto done; | |
1315 | } | |
b53ede69 | 1316 | |
511a8cfe | 1317 | r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, pivot_tmp, NULL, MS_MOVE, NULL); |
b53ede69 PW |
1318 | if (r < 0) |
1319 | goto done; | |
1320 | ||
511a8cfe | 1321 | r = mount_nofollow_verbose(LOG_ERR, directory, pivot_tmp_pivot_root_old, NULL, MS_MOVE, NULL); |
b53ede69 PW |
1322 | if (r < 0) |
1323 | goto done; | |
1324 | ||
511a8cfe | 1325 | r = mount_nofollow_verbose(LOG_ERR, pivot_tmp, directory, NULL, MS_MOVE, NULL); |
b53ede69 PW |
1326 | if (r < 0) |
1327 | goto done; | |
1328 | } else { | |
511a8cfe | 1329 | r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory, NULL, MS_MOVE, NULL); |
b53ede69 PW |
1330 | if (r < 0) |
1331 | goto done; | |
1332 | } | |
1333 | ||
1334 | done: | |
1335 | if (remove_pivot_tmp) | |
1336 | (void) rmdir(pivot_tmp); | |
1337 | ||
1338 | return r; | |
1339 | } |