1 /* SPDX-License-Identifier: LGPL-2.1+ */
7 #include <sys/statvfs.h>
10 #include "alloc-util.h"
12 #include "cgroup-util.h"
13 #include "conf-files.h"
14 #include "dev-setup.h"
24 #include "mount-setup.h"
25 #include "mountpoint-util.h"
26 #include "nulstr-util.h"
27 #include "path-util.h"
29 #include "smack-util.h"
31 #include "user-util.h"
34 typedef enum MountMode
{
37 MNT_IN_CONTAINER
= 1 << 1,
38 MNT_CHECK_WRITABLE
= 1 << 2,
41 typedef struct MountPoint
{
47 bool (*condition_fn
)(void);
51 /* The first three entries we might need before SELinux is up. The
52 * fourth (securityfs) is needed by IMA to load a custom policy. The
53 * other ones we can delay until SELinux and IMA are loaded. When
54 * SMACK is enabled we need smackfs, too, so it's a fifth one. */
56 #define N_EARLY_MOUNT 5
58 #define N_EARLY_MOUNT 4
61 static const MountPoint mount_table
[] = {
62 { "sysfs", "/sys", "sysfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
63 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
64 { "proc", "/proc", "proc", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
65 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
66 { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID
|MS_STRICTATIME
,
67 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
68 { "securityfs", "/sys/kernel/security", "securityfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
71 { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
72 mac_smack_use
, MNT_FATAL
},
73 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
74 mac_smack_use
, MNT_FATAL
},
76 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
77 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
78 { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID
), MS_NOSUID
|MS_NOEXEC
,
79 NULL
, MNT_IN_CONTAINER
},
81 { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
82 mac_smack_use
, MNT_FATAL
},
84 { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
85 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
86 { "cgroup2", "/sys/fs/cgroup", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
87 cg_is_unified_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
88 { "cgroup2", "/sys/fs/cgroup", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
89 cg_is_unified_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
90 { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
,
91 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
92 { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
93 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
94 { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
95 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
96 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
97 cg_is_legacy_wanted
, MNT_IN_CONTAINER
},
98 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
99 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
100 { "pstore", "/sys/fs/pstore", "pstore", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
103 { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
104 is_efi_boot
, MNT_NONE
},
106 { "bpf", "/sys/fs/bpf", "bpf", "mode=700", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
110 /* These are API file systems that might be mounted by other software,
111 * we just list them here so that we know that we should ignore them */
113 static const char ignore_paths
[] =
114 /* SELinux file systems */
116 /* Container bind mounts */
121 bool mount_point_is_api(const char *path
) {
124 /* Checks if this mount point is considered "API", and hence
125 * should be ignored */
127 for (i
= 0; i
< ELEMENTSOF(mount_table
); i
++)
128 if (path_equal(path
, mount_table
[i
].where
))
131 return path_startswith(path
, "/sys/fs/cgroup/");
134 bool mount_point_ignore(const char *path
) {
137 NULSTR_FOREACH(i
, ignore_paths
)
138 if (path_equal(path
, i
))
144 static int mount_one(const MountPoint
*p
, bool relabel
) {
149 priority
= (p
->mode
& MNT_FATAL
) ? LOG_ERR
: LOG_DEBUG
;
151 if (p
->condition_fn
&& !p
->condition_fn())
154 /* Relabel first, just in case */
156 (void) label_fix(p
->where
, LABEL_IGNORE_ENOENT
|LABEL_IGNORE_EROFS
);
158 r
= path_is_mount_point(p
->where
, NULL
, AT_SYMLINK_FOLLOW
);
159 if (r
< 0 && r
!= -ENOENT
) {
160 log_full_errno(priority
, r
, "Failed to determine whether %s is a mount point: %m", p
->where
);
161 return (p
->mode
& MNT_FATAL
) ? r
: 0;
166 /* Skip securityfs in a container */
167 if (!(p
->mode
& MNT_IN_CONTAINER
) && detect_container() > 0)
170 /* The access mode here doesn't really matter too much, since
171 * the mounted file system will take precedence anyway. */
173 (void) mkdir_p_label(p
->where
, 0755);
175 (void) mkdir_p(p
->where
, 0755);
177 log_debug("Mounting %s to %s of type %s with options %s.",
188 log_full_errno(priority
, errno
, "Failed to mount %s at %s: %m", p
->type
, p
->where
);
189 return (p
->mode
& MNT_FATAL
) ? -errno
: 0;
192 /* Relabel again, since we now mounted something fresh here */
194 (void) label_fix(p
->where
, 0);
196 if (p
->mode
& MNT_CHECK_WRITABLE
) {
197 if (access(p
->where
, W_OK
) < 0) {
200 (void) umount(p
->where
);
201 (void) rmdir(p
->where
);
203 log_full_errno(priority
, r
, "Mount point %s not writable after mounting: %m", p
->where
);
204 return (p
->mode
& MNT_FATAL
) ? r
: 0;
211 static int mount_points_setup(unsigned n
, bool loaded_policy
) {
215 for (i
= 0; i
< n
; i
++) {
218 j
= mount_one(mount_table
+ i
, loaded_policy
);
219 if (j
!= 0 && r
>= 0)
226 int mount_setup_early(void) {
227 assert_cc(N_EARLY_MOUNT
<= ELEMENTSOF(mount_table
));
229 /* Do a minimal mount of /proc and friends to enable the most
230 * basic stuff, such as SELinux */
231 return mount_points_setup(N_EARLY_MOUNT
, false);
234 static const char *join_with(const char *controller
) {
236 static const char* const pairs
[] = {
238 "net_cls", "net_prio",
242 const char *const *x
, *const *y
;
246 /* This will lookup which controller to mount another controller with. Input is a controller name, and output
247 * is the other controller name. The function works both ways: you can input one and get the other, and input
248 * the other to get the one. */
250 STRV_FOREACH_PAIR(x
, y
, pairs
) {
251 if (streq(controller
, *x
))
253 if (streq(controller
, *y
))
260 static int symlink_controller(const char *target
, const char *alias
) {
267 a
= strjoina("/sys/fs/cgroup/", alias
);
269 r
= symlink_idempotent(target
, a
, false);
271 return log_error_errno(r
, "Failed to create symlink %s: %m", a
);
273 #ifdef SMACK_RUN_LABEL
276 p
= strjoina("/sys/fs/cgroup/", target
);
278 r
= mac_smack_copy(a
, p
);
279 if (r
< 0 && r
!= -EOPNOTSUPP
)
280 return log_error_errno(r
, "Failed to copy smack label from %s to %s: %m", p
, a
);
286 int mount_cgroup_controllers(void) {
287 _cleanup_set_free_free_ Set
*controllers
= NULL
;
290 if (!cg_is_legacy_wanted())
293 /* Mount all available cgroup controllers that are built into the kernel. */
294 r
= cg_kernel_controllers(&controllers
);
296 return log_error_errno(r
, "Failed to enumerate cgroup controllers: %m");
299 _cleanup_free_
char *options
= NULL
, *controller
= NULL
, *where
= NULL
;
300 const char *other_controller
;
304 .flags
= MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
305 .mode
= MNT_IN_CONTAINER
,
308 controller
= set_steal_first(controllers
);
312 /* Check if we shall mount this together with another controller */
313 other_controller
= join_with(controller
);
314 if (other_controller
) {
315 _cleanup_free_
char *c
= NULL
;
317 /* Check if the other controller is actually available in the kernel too */
318 c
= set_remove(controllers
, other_controller
);
321 /* Join the two controllers into one string, and maintain a stable ordering */
322 if (strcmp(controller
, other_controller
) < 0)
323 options
= strjoin(controller
, ",", other_controller
);
325 options
= strjoin(other_controller
, ",", controller
);
331 /* The simple case, where there's only one controller to mount together */
333 options
= TAKE_PTR(controller
);
335 where
= path_join("/sys/fs/cgroup", options
);
342 r
= mount_one(&p
, true);
346 /* Create symlinks from the individual controller names, in case we have a joined mount */
348 (void) symlink_controller(options
, controller
);
349 if (other_controller
)
350 (void) symlink_controller(options
, other_controller
);
353 /* Now that we mounted everything, let's make the tmpfs the cgroup file systems are mounted into read-only. */
354 (void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT
|MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
|MS_RDONLY
, "mode=755");
359 #if HAVE_SELINUX || ENABLE_SMACK
362 const struct stat
*sb
,
364 struct FTW
*ftwbuf
) {
366 /* No need to label /dev twice in a row... */
367 if (_unlikely_(ftwbuf
->level
== 0))
370 (void) label_fix(fpath
, 0);
372 /* /run/initramfs is static data and big, no need to
373 * dynamically relabel its contents at boot... */
374 if (_unlikely_(ftwbuf
->level
== 1 &&
376 streq(fpath
, "/run/initramfs")))
377 return FTW_SKIP_SUBTREE
;
382 static int relabel_cgroup_filesystems(void) {
386 r
= cg_all_unified();
388 /* Temporarily remount the root cgroup filesystem to give it a proper label. Do this
389 only when the filesystem has been already populated by a previous instance of systemd
390 running from initrd. Otherwise don't remount anything and leave the filesystem read-write
391 for the cgroup filesystems to be mounted inside. */
392 if (statfs("/sys/fs/cgroup", &st
) < 0)
393 return log_error_errno(errno
, "Failed to determine mount flags for /sys/fs/cgroup: %m");
395 if (st
.f_flags
& ST_RDONLY
)
396 (void) mount(NULL
, "/sys/fs/cgroup", NULL
, MS_REMOUNT
, NULL
);
398 (void) label_fix("/sys/fs/cgroup", 0);
399 (void) nftw("/sys/fs/cgroup", nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
401 if (st
.f_flags
& ST_RDONLY
)
402 (void) mount(NULL
, "/sys/fs/cgroup", NULL
, MS_REMOUNT
|MS_RDONLY
, NULL
);
405 return log_error_errno(r
, "Failed to determine whether we are in all unified mode: %m");
410 static int relabel_extra(void) {
411 _cleanup_strv_free_
char **files
= NULL
;
415 /* Support for relabelling additional files or directories after loading the policy. For this, code in the
416 * initrd simply has to drop in *.relabel files into /run/systemd/relabel-extra.d/. We'll read all such files
417 * expecting one absolute path by line and will relabel each (and everyone below that in case the path refers
418 * to a directory). These drop-in files are supposed to be absolutely minimal, and do not understand comments
419 * and such. After the operation succeeded the files are removed, and the drop-in directory as well, if
423 r
= conf_files_list(&files
, ".relabel", NULL
,
424 CONF_FILES_FILTER_MASKED
| CONF_FILES_REGULAR
,
425 "/run/systemd/relabel-extra.d/");
427 return log_error_errno(r
, "Failed to enumerate /run/systemd/relabel-extra.d/, ignoring: %m");
429 STRV_FOREACH(file
, files
) {
430 _cleanup_fclose_
FILE *f
= NULL
;
432 f
= fopen(*file
, "re");
434 log_warning_errno(errno
, "Failed to open %s, ignoring: %m", *file
);
439 _cleanup_free_
char *line
= NULL
;
441 r
= read_line(f
, LONG_LINE_MAX
, &line
);
443 log_warning_errno(r
, "Failed to read %s, ignoring: %m", *file
);
446 if (r
== 0) /* EOF */
449 path_simplify(line
, true);
451 if (!path_is_normalized(line
)) {
452 log_warning("Path to relabel is not normalized, ignoring: %s", line
);
456 if (!path_is_absolute(line
)) {
457 log_warning("Path to relabel is not absolute, ignoring: %s", line
);
461 log_debug("Relabelling additional file/directory '%s'.", line
);
462 (void) label_fix(line
, 0);
463 (void) nftw(line
, nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
467 if (unlink(*file
) < 0)
468 log_warning_errno(errno
, "Failed to remove %s, ignoring: %m", *file
);
471 /* Remove when we complete things. */
472 if (rmdir("/run/systemd/relabel-extra.d") < 0)
473 log_warning_errno(errno
, "Failed to remove /run/systemd/relabel-extra.d/ directory: %m");
479 int mount_setup(bool loaded_policy
) {
482 r
= mount_points_setup(ELEMENTSOF(mount_table
), loaded_policy
);
486 #if HAVE_SELINUX || ENABLE_SMACK
487 /* Nodes in devtmpfs and /run need to be manually updated for
488 * the appropriate labels, after mounting. The other virtual
489 * API file systems like /sys and /proc do not need that, they
490 * use the same label for all their files. */
492 usec_t before_relabel
, after_relabel
;
493 char timespan
[FORMAT_TIMESPAN_MAX
];
497 before_relabel
= now(CLOCK_MONOTONIC
);
499 FOREACH_STRING(i
, "/dev", "/dev/shm", "/run")
500 (void) nftw(i
, nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
502 (void) relabel_cgroup_filesystems();
504 n_extra
= relabel_extra();
506 after_relabel
= now(CLOCK_MONOTONIC
);
508 log_info("Relabelled /dev, /dev/shm, /run, /sys/fs/cgroup%s in %s.",
509 n_extra
> 0 ? ", additional files" : "",
510 format_timespan(timespan
, sizeof(timespan
), after_relabel
- before_relabel
, 0));
514 /* Create a few default symlinks, which are normally created
515 * by udevd, but some scripts might need them before we start
517 dev_setup(NULL
, UID_INVALID
, GID_INVALID
);
519 /* Mark the root directory as shared in regards to mount propagation. The kernel defaults to "private", but we
520 * think it makes more sense to have a default of "shared" so that nspawn and the container tools work out of
521 * the box. If specific setups need other settings they can reset the propagation mode to private if
522 * needed. Note that we set this only when we are invoked directly by the kernel. If we are invoked by a
523 * container manager we assume the container manager knows what it is doing (for example, because it set up
524 * some directories with different propagation modes). */
525 if (detect_container() <= 0)
526 if (mount(NULL
, "/", NULL
, MS_REC
|MS_SHARED
, NULL
) < 0)
527 log_warning_errno(errno
, "Failed to set up the root directory for shared mount propagation: %m");
529 /* Create a few directories we always want around, Note that sd_booted() checks for /run/systemd/system, so
530 * this mkdir really needs to stay for good, otherwise software that copied sd-daemon.c into their sources will
531 * misdetect systemd. */
532 (void) mkdir_label("/run/systemd", 0755);
533 (void) mkdir_label("/run/systemd/system", 0755);
535 /* Also create /run/systemd/inaccessible nodes, so that we always have something to mount inaccessible nodes
537 (void) make_inaccessible_nodes(NULL
, UID_INVALID
, GID_INVALID
);