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 "cgroup-setup.h"
15 #include "dev-setup.h"
16 #include "dirent-util.h"
17 #include "efi-loader.h"
25 #include "mount-setup.h"
26 #include "mountpoint-util.h"
27 #include "nulstr-util.h"
28 #include "path-util.h"
30 #include "smack-util.h"
32 #include "user-util.h"
35 typedef enum MountMode
{
38 MNT_IN_CONTAINER
= 1 << 1,
39 MNT_CHECK_WRITABLE
= 1 << 2,
42 typedef struct MountPoint
{
48 bool (*condition_fn
)(void);
52 /* The first three entries we might need before SELinux is up. The
53 * fourth (securityfs) is needed by IMA to load a custom policy. The
54 * other ones we can delay until SELinux and IMA are loaded. When
55 * SMACK is enabled we need smackfs, too, so it's a fifth one. */
57 #define N_EARLY_MOUNT 5
59 #define N_EARLY_MOUNT 4
62 static const MountPoint mount_table
[] = {
63 { "sysfs", "/sys", "sysfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
64 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
65 { "proc", "/proc", "proc", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
66 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
67 { "devtmpfs", "/dev", "devtmpfs", "mode=755", MS_NOSUID
|MS_NOEXEC
|MS_STRICTATIME
,
68 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
69 { "securityfs", "/sys/kernel/security", "securityfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
72 { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
73 mac_smack_use
, MNT_FATAL
},
74 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
75 mac_smack_use
, MNT_FATAL
},
77 { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
78 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
79 { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID
), MS_NOSUID
|MS_NOEXEC
,
80 NULL
, MNT_IN_CONTAINER
},
82 { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
83 mac_smack_use
, MNT_FATAL
},
85 { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID
|MS_NODEV
|MS_STRICTATIME
,
86 NULL
, MNT_FATAL
|MNT_IN_CONTAINER
},
87 { "cgroup2", "/sys/fs/cgroup", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
88 cg_is_unified_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
89 { "cgroup2", "/sys/fs/cgroup", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
90 cg_is_unified_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
91 { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=755", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
,
92 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
93 { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", "nsdelegate", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
94 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
95 { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
96 cg_is_hybrid_wanted
, MNT_IN_CONTAINER
|MNT_CHECK_WRITABLE
},
97 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
98 cg_is_legacy_wanted
, MNT_IN_CONTAINER
},
99 { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
100 cg_is_legacy_wanted
, MNT_FATAL
|MNT_IN_CONTAINER
},
101 { "pstore", "/sys/fs/pstore", "pstore", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
104 { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL
, MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
105 is_efi_boot
, MNT_NONE
},
107 { "bpf", "/sys/fs/bpf", "bpf", "mode=700", MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
111 /* These are API file systems that might be mounted by other software,
112 * we just list them here so that we know that we should ignore them */
114 static const char ignore_paths
[] =
115 /* SELinux file systems */
117 /* Container bind mounts */
122 bool mount_point_is_api(const char *path
) {
125 /* Checks if this mount point is considered "API", and hence
126 * should be ignored */
128 for (i
= 0; i
< ELEMENTSOF(mount_table
); i
++)
129 if (path_equal(path
, mount_table
[i
].where
))
132 return path_startswith(path
, "/sys/fs/cgroup/");
135 bool mount_point_ignore(const char *path
) {
138 NULSTR_FOREACH(i
, ignore_paths
)
139 if (path_equal(path
, i
))
145 static int mount_one(const MountPoint
*p
, bool relabel
) {
150 priority
= (p
->mode
& MNT_FATAL
) ? LOG_ERR
: LOG_DEBUG
;
152 if (p
->condition_fn
&& !p
->condition_fn())
155 /* Relabel first, just in case */
157 (void) label_fix(p
->where
, LABEL_IGNORE_ENOENT
|LABEL_IGNORE_EROFS
);
159 r
= path_is_mount_point(p
->where
, NULL
, AT_SYMLINK_FOLLOW
);
160 if (r
< 0 && r
!= -ENOENT
) {
161 log_full_errno(priority
, r
, "Failed to determine whether %s is a mount point: %m", p
->where
);
162 return (p
->mode
& MNT_FATAL
) ? r
: 0;
167 /* Skip securityfs in a container */
168 if (!(p
->mode
& MNT_IN_CONTAINER
) && detect_container() > 0)
171 /* The access mode here doesn't really matter too much, since
172 * the mounted file system will take precedence anyway. */
174 (void) mkdir_p_label(p
->where
, 0755);
176 (void) mkdir_p(p
->where
, 0755);
178 log_debug("Mounting %s to %s of type %s with options %s.",
189 log_full_errno(priority
, errno
, "Failed to mount %s at %s: %m", p
->type
, p
->where
);
190 return (p
->mode
& MNT_FATAL
) ? -errno
: 0;
193 /* Relabel again, since we now mounted something fresh here */
195 (void) label_fix(p
->where
, 0);
197 if (p
->mode
& MNT_CHECK_WRITABLE
) {
198 if (access(p
->where
, W_OK
) < 0) {
201 (void) umount(p
->where
);
202 (void) rmdir(p
->where
);
204 log_full_errno(priority
, r
, "Mount point %s not writable after mounting: %m", p
->where
);
205 return (p
->mode
& MNT_FATAL
) ? r
: 0;
212 static int mount_points_setup(unsigned n
, bool loaded_policy
) {
216 for (i
= 0; i
< n
; i
++) {
219 j
= mount_one(mount_table
+ i
, loaded_policy
);
220 if (j
!= 0 && r
>= 0)
227 int mount_setup_early(void) {
228 assert_cc(N_EARLY_MOUNT
<= ELEMENTSOF(mount_table
));
230 /* Do a minimal mount of /proc and friends to enable the most
231 * basic stuff, such as SELinux */
232 return mount_points_setup(N_EARLY_MOUNT
, false);
235 static const char *join_with(const char *controller
) {
237 static const char* const pairs
[] = {
239 "net_cls", "net_prio",
243 const char *const *x
, *const *y
;
247 /* This will lookup which controller to mount another controller with. Input is a controller name, and output
248 * is the other controller name. The function works both ways: you can input one and get the other, and input
249 * the other to get the one. */
251 STRV_FOREACH_PAIR(x
, y
, pairs
) {
252 if (streq(controller
, *x
))
254 if (streq(controller
, *y
))
261 static int symlink_controller(const char *target
, const char *alias
) {
268 a
= strjoina("/sys/fs/cgroup/", alias
);
270 r
= symlink_idempotent(target
, a
, false);
272 return log_error_errno(r
, "Failed to create symlink %s: %m", a
);
274 #ifdef SMACK_RUN_LABEL
277 p
= strjoina("/sys/fs/cgroup/", target
);
279 r
= mac_smack_copy(a
, p
);
280 if (r
< 0 && r
!= -EOPNOTSUPP
)
281 return log_error_errno(r
, "Failed to copy smack label from %s to %s: %m", p
, a
);
287 int mount_cgroup_controllers(void) {
288 _cleanup_set_free_free_ Set
*controllers
= NULL
;
291 if (!cg_is_legacy_wanted())
294 /* Mount all available cgroup controllers that are built into the kernel. */
295 r
= cg_kernel_controllers(&controllers
);
297 return log_error_errno(r
, "Failed to enumerate cgroup controllers: %m");
300 _cleanup_free_
char *options
= NULL
, *controller
= NULL
, *where
= NULL
;
301 const char *other_controller
;
305 .flags
= MS_NOSUID
|MS_NOEXEC
|MS_NODEV
,
306 .mode
= MNT_IN_CONTAINER
,
309 controller
= set_steal_first(controllers
);
313 /* Check if we shall mount this together with another controller */
314 other_controller
= join_with(controller
);
315 if (other_controller
) {
316 _cleanup_free_
char *c
= NULL
;
318 /* Check if the other controller is actually available in the kernel too */
319 c
= set_remove(controllers
, other_controller
);
322 /* Join the two controllers into one string, and maintain a stable ordering */
323 if (strcmp(controller
, other_controller
) < 0)
324 options
= strjoin(controller
, ",", other_controller
);
326 options
= strjoin(other_controller
, ",", controller
);
332 /* The simple case, where there's only one controller to mount together */
334 options
= TAKE_PTR(controller
);
336 where
= path_join("/sys/fs/cgroup", options
);
343 r
= mount_one(&p
, true);
347 /* Create symlinks from the individual controller names, in case we have a joined mount */
349 (void) symlink_controller(options
, controller
);
350 if (other_controller
)
351 (void) symlink_controller(options
, other_controller
);
354 /* Now that we mounted everything, let's make the tmpfs the cgroup file systems are mounted into read-only. */
355 (void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT
|MS_NOSUID
|MS_NOEXEC
|MS_NODEV
|MS_STRICTATIME
|MS_RDONLY
, "mode=755");
360 #if HAVE_SELINUX || ENABLE_SMACK
363 const struct stat
*sb
,
365 struct FTW
*ftwbuf
) {
367 /* No need to label /dev twice in a row... */
368 if (_unlikely_(ftwbuf
->level
== 0))
371 (void) label_fix(fpath
, 0);
373 /* /run/initramfs is static data and big, no need to
374 * dynamically relabel its contents at boot... */
375 if (_unlikely_(ftwbuf
->level
== 1 &&
377 streq(fpath
, "/run/initramfs")))
378 return FTW_SKIP_SUBTREE
;
383 static int relabel_cgroup_filesystems(void) {
387 r
= cg_all_unified();
389 /* Temporarily remount the root cgroup filesystem to give it a proper label. Do this
390 only when the filesystem has been already populated by a previous instance of systemd
391 running from initrd. Otherwise don't remount anything and leave the filesystem read-write
392 for the cgroup filesystems to be mounted inside. */
393 if (statfs("/sys/fs/cgroup", &st
) < 0)
394 return log_error_errno(errno
, "Failed to determine mount flags for /sys/fs/cgroup: %m");
396 if (st
.f_flags
& ST_RDONLY
)
397 (void) mount(NULL
, "/sys/fs/cgroup", NULL
, MS_REMOUNT
, NULL
);
399 (void) label_fix("/sys/fs/cgroup", 0);
400 (void) nftw("/sys/fs/cgroup", nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
402 if (st
.f_flags
& ST_RDONLY
)
403 (void) mount(NULL
, "/sys/fs/cgroup", NULL
, MS_REMOUNT
|MS_RDONLY
, NULL
);
406 return log_error_errno(r
, "Failed to determine whether we are in all unified mode: %m");
411 static int relabel_extra(void) {
412 _cleanup_strv_free_
char **files
= NULL
;
416 /* Support for relabelling additional files or directories after loading the policy. For this, code in the
417 * initrd simply has to drop in *.relabel files into /run/systemd/relabel-extra.d/. We'll read all such files
418 * expecting one absolute path by line and will relabel each (and everyone below that in case the path refers
419 * to a directory). These drop-in files are supposed to be absolutely minimal, and do not understand comments
420 * and such. After the operation succeeded the files are removed, and the drop-in directory as well, if
424 r
= conf_files_list(&files
, ".relabel", NULL
,
425 CONF_FILES_FILTER_MASKED
| CONF_FILES_REGULAR
,
426 "/run/systemd/relabel-extra.d/");
428 return log_error_errno(r
, "Failed to enumerate /run/systemd/relabel-extra.d/, ignoring: %m");
430 STRV_FOREACH(file
, files
) {
431 _cleanup_fclose_
FILE *f
= NULL
;
433 f
= fopen(*file
, "re");
435 log_warning_errno(errno
, "Failed to open %s, ignoring: %m", *file
);
440 _cleanup_free_
char *line
= NULL
;
442 r
= read_line(f
, LONG_LINE_MAX
, &line
);
444 log_warning_errno(r
, "Failed to read %s, ignoring: %m", *file
);
447 if (r
== 0) /* EOF */
450 path_simplify(line
, true);
452 if (!path_is_normalized(line
)) {
453 log_warning("Path to relabel is not normalized, ignoring: %s", line
);
457 if (!path_is_absolute(line
)) {
458 log_warning("Path to relabel is not absolute, ignoring: %s", line
);
462 log_debug("Relabelling additional file/directory '%s'.", line
);
463 (void) label_fix(line
, 0);
464 (void) nftw(line
, nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
468 if (unlink(*file
) < 0)
469 log_warning_errno(errno
, "Failed to remove %s, ignoring: %m", *file
);
472 /* Remove when we complete things. */
473 if (rmdir("/run/systemd/relabel-extra.d") < 0 &&
475 log_warning_errno(errno
, "Failed to remove /run/systemd/relabel-extra.d/ directory: %m");
481 int mount_setup(bool loaded_policy
, bool leave_propagation
) {
484 r
= mount_points_setup(ELEMENTSOF(mount_table
), loaded_policy
);
488 #if HAVE_SELINUX || ENABLE_SMACK
489 /* Nodes in devtmpfs and /run need to be manually updated for
490 * the appropriate labels, after mounting. The other virtual
491 * API file systems like /sys and /proc do not need that, they
492 * use the same label for all their files. */
494 usec_t before_relabel
, after_relabel
;
495 char timespan
[FORMAT_TIMESPAN_MAX
];
499 before_relabel
= now(CLOCK_MONOTONIC
);
501 FOREACH_STRING(i
, "/dev", "/dev/shm", "/run")
502 (void) nftw(i
, nftw_cb
, 64, FTW_MOUNT
|FTW_PHYS
|FTW_ACTIONRETVAL
);
504 (void) relabel_cgroup_filesystems();
506 n_extra
= relabel_extra();
508 after_relabel
= now(CLOCK_MONOTONIC
);
510 log_info("Relabelled /dev, /dev/shm, /run, /sys/fs/cgroup%s in %s.",
511 n_extra
> 0 ? ", additional files" : "",
512 format_timespan(timespan
, sizeof(timespan
), after_relabel
- before_relabel
, 0));
516 /* Create a few default symlinks, which are normally created
517 * by udevd, but some scripts might need them before we start
519 dev_setup(NULL
, UID_INVALID
, GID_INVALID
);
521 /* Mark the root directory as shared in regards to mount propagation. The kernel defaults to "private", but we
522 * think it makes more sense to have a default of "shared" so that nspawn and the container tools work out of
523 * the box. If specific setups need other settings they can reset the propagation mode to private if
524 * needed. Note that we set this only when we are invoked directly by the kernel. If we are invoked by a
525 * container manager we assume the container manager knows what it is doing (for example, because it set up
526 * some directories with different propagation modes). */
527 if (detect_container() <= 0 && !leave_propagation
)
528 if (mount(NULL
, "/", NULL
, MS_REC
|MS_SHARED
, NULL
) < 0)
529 log_warning_errno(errno
, "Failed to set up the root directory for shared mount propagation: %m");
531 /* Create a few directories we always want around, Note that sd_booted() checks for /run/systemd/system, so
532 * this mkdir really needs to stay for good, otherwise software that copied sd-daemon.c into their sources will
533 * misdetect systemd. */
534 (void) mkdir_label("/run/systemd", 0755);
535 (void) mkdir_label("/run/systemd/system", 0755);
537 /* Also create /run/systemd/inaccessible nodes, so that we always have something to mount inaccessible nodes
539 (void) make_inaccessible_nodes("/run/systemd", UID_INVALID
, GID_INVALID
);