Line data Source code
1 : /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
2 :
3 : /***
4 : This file is part of systemd.
5 :
6 : Copyright 2010 Lennart Poettering
7 :
8 : systemd is free software; you can redistribute it and/or modify it
9 : under the terms of the GNU Lesser General Public License as published by
10 : the Free Software Foundation; either version 2.1 of the License, or
11 : (at your option) any later version.
12 :
13 : systemd is distributed in the hope that it will be useful, but
14 : WITHOUT ANY WARRANTY; without even the implied warranty of
15 : MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 : Lesser General Public License for more details.
17 :
18 : You should have received a copy of the GNU Lesser General Public License
19 : along with systemd; If not, see <http://www.gnu.org/licenses/>.
20 : ***/
21 :
22 : #include <sys/mount.h>
23 : #include <errno.h>
24 : #include <stdlib.h>
25 : #include <unistd.h>
26 : #include <ftw.h>
27 :
28 : #include "mount-setup.h"
29 : #include "dev-setup.h"
30 : #include "bus-util.h"
31 : #include "log.h"
32 : #include "macro.h"
33 : #include "util.h"
34 : #include "label.h"
35 : #include "set.h"
36 : #include "strv.h"
37 : #include "mkdir.h"
38 : #include "path-util.h"
39 : #include "missing.h"
40 : #include "virt.h"
41 : #include "efivars.h"
42 : #include "smack-util.h"
43 : #include "cgroup-util.h"
44 :
45 : typedef enum MountMode {
46 : MNT_NONE = 0,
47 : MNT_FATAL = 1 << 0,
48 : MNT_IN_CONTAINER = 1 << 1,
49 : } MountMode;
50 :
51 : typedef struct MountPoint {
52 : const char *what;
53 : const char *where;
54 : const char *type;
55 : const char *options;
56 : unsigned long flags;
57 : bool (*condition_fn)(void);
58 : MountMode mode;
59 : } MountPoint;
60 :
61 : /* The first three entries we might need before SELinux is up. The
62 : * fourth (securityfs) is needed by IMA to load a custom policy. The
63 : * other ones we can delay until SELinux and IMA are loaded. When
64 : * SMACK is enabled we need smackfs, too, so it's a fifth one. */
65 : #ifdef HAVE_SMACK
66 : #define N_EARLY_MOUNT 5
67 : #else
68 : #define N_EARLY_MOUNT 4
69 : #endif
70 :
71 : static const MountPoint mount_table[] = {
72 : { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
73 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
74 : { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
75 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
76 : { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME,
77 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
78 : { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
79 : NULL, MNT_NONE },
80 : #ifdef HAVE_SMACK
81 : { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID|MS_NOEXEC|MS_NODEV,
82 : mac_smack_use, MNT_FATAL },
83 : { "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
84 : mac_smack_use, MNT_FATAL },
85 : #endif
86 : { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
87 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
88 : { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC,
89 : NULL, MNT_IN_CONTAINER },
90 : #ifdef HAVE_SMACK
91 : { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
92 : mac_smack_use, MNT_FATAL },
93 : #endif
94 : { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME,
95 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
96 : { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME,
97 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
98 : { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID|MS_NOEXEC|MS_NODEV,
99 : NULL, MNT_IN_CONTAINER },
100 : { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV,
101 : NULL, MNT_FATAL|MNT_IN_CONTAINER },
102 : { "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
103 : NULL, MNT_NONE },
104 : #ifdef ENABLE_EFI
105 : { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
106 : is_efi_boot, MNT_NONE },
107 : #endif
108 : { "kdbusfs", "/sys/fs/kdbus", "kdbusfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV,
109 : is_kdbus_wanted, MNT_IN_CONTAINER },
110 : };
111 :
112 : /* These are API file systems that might be mounted by other software,
113 : * we just list them here so that we know that we should ignore them */
114 :
115 : static const char ignore_paths[] =
116 : /* SELinux file systems */
117 : "/sys/fs/selinux\0"
118 : /* Container bind mounts */
119 : "/proc/sys\0"
120 : "/dev/console\0"
121 : "/proc/kmsg\0";
122 :
123 370 : bool mount_point_is_api(const char *path) {
124 : unsigned i;
125 :
126 : /* Checks if this mount point is considered "API", and hence
127 : * should be ignored */
128 :
129 5260 : for (i = 0; i < ELEMENTSOF(mount_table); i ++)
130 5010 : if (path_equal(path, mount_table[i].where))
131 120 : return true;
132 :
133 250 : return path_startswith(path, "/sys/fs/cgroup/");
134 : }
135 :
136 180 : bool mount_point_ignore(const char *path) {
137 : const char *i;
138 :
139 900 : NULSTR_FOREACH(i, ignore_paths)
140 720 : if (path_equal(path, i))
141 0 : return true;
142 :
143 180 : return false;
144 : }
145 :
146 0 : static int mount_one(const MountPoint *p, bool relabel) {
147 : int r;
148 :
149 0 : assert(p);
150 :
151 0 : if (p->condition_fn && !p->condition_fn())
152 0 : return 0;
153 :
154 : /* Relabel first, just in case */
155 0 : if (relabel)
156 0 : label_fix(p->where, true, true);
157 :
158 0 : r = path_is_mount_point(p->where, AT_SYMLINK_FOLLOW);
159 0 : if (r < 0 && r != -ENOENT)
160 0 : return r;
161 0 : if (r > 0)
162 0 : return 0;
163 :
164 : /* Skip securityfs in a container */
165 0 : if (!(p->mode & MNT_IN_CONTAINER) && detect_container(NULL) > 0)
166 0 : return 0;
167 :
168 : /* The access mode here doesn't really matter too much, since
169 : * the mounted file system will take precedence anyway. */
170 0 : if (relabel)
171 0 : mkdir_p_label(p->where, 0755);
172 : else
173 0 : mkdir_p(p->where, 0755);
174 :
175 0 : log_debug("Mounting %s to %s of type %s with options %s.",
176 : p->what,
177 : p->where,
178 : p->type,
179 : strna(p->options));
180 :
181 0 : if (mount(p->what,
182 : p->where,
183 : p->type,
184 : p->flags,
185 0 : p->options) < 0) {
186 0 : log_full((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, "Failed to mount %s at %s: %m", p->type, p->where);
187 0 : return (p->mode & MNT_FATAL) ? -errno : 0;
188 : }
189 :
190 : /* Relabel again, since we now mounted something fresh here */
191 0 : if (relabel)
192 0 : label_fix(p->where, false, false);
193 :
194 0 : return 1;
195 : }
196 :
197 0 : int mount_setup_early(void) {
198 : unsigned i;
199 0 : int r = 0;
200 :
201 : assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table));
202 :
203 : /* Do a minimal mount of /proc and friends to enable the most
204 : * basic stuff, such as SELinux */
205 0 : for (i = 0; i < N_EARLY_MOUNT; i ++) {
206 : int j;
207 :
208 0 : j = mount_one(mount_table + i, false);
209 0 : if (r == 0)
210 0 : r = j;
211 : }
212 :
213 0 : return r;
214 : }
215 :
216 0 : int mount_cgroup_controllers(char ***join_controllers) {
217 0 : _cleanup_set_free_free_ Set *controllers = NULL;
218 : int r;
219 :
220 : /* Mount all available cgroup controllers that are built into the kernel. */
221 :
222 0 : controllers = set_new(&string_hash_ops);
223 0 : if (!controllers)
224 0 : return log_oom();
225 :
226 0 : r = cg_kernel_controllers(controllers);
227 0 : if (r < 0)
228 0 : return log_error_errno(r, "Failed to enumerate cgroup controllers: %m");
229 :
230 : for (;;) {
231 0 : _cleanup_free_ char *options = NULL, *controller = NULL, *where = NULL;
232 0 : MountPoint p = {
233 : .what = "cgroup",
234 : .type = "cgroup",
235 : .flags = MS_NOSUID|MS_NOEXEC|MS_NODEV,
236 : .mode = MNT_IN_CONTAINER,
237 : };
238 0 : char ***k = NULL;
239 :
240 0 : controller = set_steal_first(controllers);
241 0 : if (!controller)
242 0 : break;
243 :
244 0 : if (join_controllers)
245 0 : for (k = join_controllers; *k; k++)
246 0 : if (strv_find(*k, controller))
247 0 : break;
248 :
249 0 : if (k && *k) {
250 : char **i, **j;
251 :
252 0 : for (i = *k, j = *k; *i; i++) {
253 :
254 0 : if (!streq(*i, controller)) {
255 0 : _cleanup_free_ char *t;
256 :
257 0 : t = set_remove(controllers, *i);
258 0 : if (!t) {
259 0 : free(*i);
260 0 : continue;
261 : }
262 : }
263 :
264 0 : *(j++) = *i;
265 : }
266 :
267 0 : *j = NULL;
268 :
269 0 : options = strv_join(*k, ",");
270 0 : if (!options)
271 0 : return log_oom();
272 : } else {
273 0 : options = controller;
274 0 : controller = NULL;
275 : }
276 :
277 0 : where = strappend("/sys/fs/cgroup/", options);
278 0 : if (!where)
279 0 : return log_oom();
280 :
281 0 : p.where = where;
282 0 : p.options = options;
283 :
284 0 : r = mount_one(&p, true);
285 0 : if (r < 0)
286 0 : return r;
287 :
288 0 : if (r > 0 && k && *k) {
289 : char **i;
290 :
291 0 : for (i = *k; *i; i++) {
292 0 : _cleanup_free_ char *t = NULL;
293 :
294 0 : t = strappend("/sys/fs/cgroup/", *i);
295 0 : if (!t)
296 0 : return log_oom();
297 :
298 0 : r = symlink(options, t);
299 0 : if (r < 0 && errno != EEXIST)
300 0 : return log_error_errno(errno, "Failed to create symlink %s: %m", t);
301 : }
302 : }
303 0 : }
304 :
305 : /* Now that we mounted everything, let's make the tmpfs the
306 : * cgroup file systems are mounted into read-only. */
307 0 : (void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755");
308 :
309 0 : return 0;
310 : }
311 :
312 : #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
313 0 : static int nftw_cb(
314 : const char *fpath,
315 : const struct stat *sb,
316 : int tflag,
317 : struct FTW *ftwbuf) {
318 :
319 : /* No need to label /dev twice in a row... */
320 0 : if (_unlikely_(ftwbuf->level == 0))
321 0 : return FTW_CONTINUE;
322 :
323 0 : label_fix(fpath, false, false);
324 :
325 : /* /run/initramfs is static data and big, no need to
326 : * dynamically relabel its contents at boot... */
327 0 : if (_unlikely_(ftwbuf->level == 1 &&
328 : tflag == FTW_D &&
329 : streq(fpath, "/run/initramfs")))
330 0 : return FTW_SKIP_SUBTREE;
331 :
332 0 : return FTW_CONTINUE;
333 : };
334 : #endif
335 :
336 0 : int mount_setup(bool loaded_policy) {
337 : unsigned i;
338 0 : int r = 0;
339 :
340 0 : for (i = 0; i < ELEMENTSOF(mount_table); i ++) {
341 : int j;
342 :
343 0 : j = mount_one(mount_table + i, loaded_policy);
344 0 : if (r == 0)
345 0 : r = j;
346 : }
347 :
348 0 : if (r < 0)
349 0 : return r;
350 :
351 : #if defined(HAVE_SELINUX) || defined(HAVE_SMACK)
352 : /* Nodes in devtmpfs and /run need to be manually updated for
353 : * the appropriate labels, after mounting. The other virtual
354 : * API file systems like /sys and /proc do not need that, they
355 : * use the same label for all their files. */
356 0 : if (loaded_policy) {
357 : usec_t before_relabel, after_relabel;
358 : char timespan[FORMAT_TIMESPAN_MAX];
359 :
360 0 : before_relabel = now(CLOCK_MONOTONIC);
361 :
362 0 : nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
363 0 : nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL);
364 :
365 0 : after_relabel = now(CLOCK_MONOTONIC);
366 :
367 0 : log_info("Relabelled /dev and /run in %s.",
368 : format_timespan(timespan, sizeof(timespan), after_relabel - before_relabel, 0));
369 : }
370 : #endif
371 :
372 : /* Create a few default symlinks, which are normally created
373 : * by udevd, but some scripts might need them before we start
374 : * udevd. */
375 0 : dev_setup(NULL, UID_INVALID, GID_INVALID);
376 :
377 : /* Mark the root directory as shared in regards to mount
378 : * propagation. The kernel defaults to "private", but we think
379 : * it makes more sense to have a default of "shared" so that
380 : * nspawn and the container tools work out of the box. If
381 : * specific setups need other settings they can reset the
382 : * propagation mode to private if needed. */
383 0 : if (detect_container(NULL) <= 0)
384 0 : if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0)
385 0 : log_warning_errno(errno, "Failed to set up the root directory for shared mount propagation: %m");
386 :
387 : /* Create a few directories we always want around, Note that
388 : * sd_booted() checks for /run/systemd/system, so this mkdir
389 : * really needs to stay for good, otherwise software that
390 : * copied sd-daemon.c into their sources will misdetect
391 : * systemd. */
392 0 : mkdir_label("/run/systemd", 0755);
393 0 : mkdir_label("/run/systemd/system", 0755);
394 0 : mkdir_label("/run/systemd/inaccessible", 0000);
395 :
396 0 : return 0;
397 : }
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