| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <errno.h> |
| #include <stdlib.h> |
| #include <sys/mount.h> |
| #include <sys/statvfs.h> |
| #include <unistd.h> |
| |
| #include "alloc-util.h" |
| #include "bus-util.h" |
| #include "cgroup-setup.h" |
| #include "cgroup-util.h" |
| #include "conf-files.h" |
| #include "dev-setup.h" |
| #include "dirent-util.h" |
| #include "efi-loader.h" |
| #include "fd-util.h" |
| #include "fileio.h" |
| #include "fs-util.h" |
| #include "label.h" |
| #include "log.h" |
| #include "macro.h" |
| #include "mkdir-label.h" |
| #include "mount-setup.h" |
| #include "mount-util.h" |
| #include "mountpoint-util.h" |
| #include "nulstr-util.h" |
| #include "path-util.h" |
| #include "recurse-dir.h" |
| #include "set.h" |
| #include "smack-util.h" |
| #include "strv.h" |
| #include "user-util.h" |
| #include "virt.h" |
| |
| typedef enum MountMode { |
| MNT_NONE = 0, |
| MNT_FATAL = 1 << 0, |
| MNT_IN_CONTAINER = 1 << 1, |
| MNT_CHECK_WRITABLE = 1 << 2, |
| MNT_FOLLOW_SYMLINK = 1 << 3, |
| } MountMode; |
| |
| typedef struct MountPoint { |
| const char *what; |
| const char *where; |
| const char *type; |
| const char *options; |
| unsigned long flags; |
| bool (*condition_fn)(void); |
| MountMode mode; |
| } MountPoint; |
| |
| /* The first three entries we might need before SELinux is up. The |
| * fourth (securityfs) is needed by IMA to load a custom policy. The |
| * other ones we can delay until SELinux and IMA are loaded. When |
| * SMACK is enabled we need smackfs, too, so it's a fifth one. */ |
| #if ENABLE_SMACK |
| #define N_EARLY_MOUNT 5 |
| #else |
| #define N_EARLY_MOUNT 4 |
| #endif |
| |
| static const MountPoint mount_table[] = { |
| { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER|MNT_FOLLOW_SYMLINK }, |
| { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "devtmpfs", "/dev", "devtmpfs", "mode=0755" TMPFS_LIMITS_DEV, MS_NOSUID|MS_STRICTATIME, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "securityfs", "/sys/kernel/security", "securityfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_NONE }, |
| #if ENABLE_SMACK |
| { "smackfs", "/sys/fs/smackfs", "smackfs", "smackfsdef=*", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| mac_smack_use, MNT_FATAL }, |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=01777,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| mac_smack_use, MNT_FATAL }, |
| #endif |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=01777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "devpts", "/dev/pts", "devpts", "mode=0620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, |
| NULL, MNT_IN_CONTAINER }, |
| #if ENABLE_SMACK |
| { "tmpfs", "/run", "tmpfs", "mode=0755,smackfsroot=*" TMPFS_LIMITS_RUN, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| mac_smack_use, MNT_FATAL }, |
| #endif |
| { "tmpfs", "/run", "tmpfs", "mode=0755" TMPFS_LIMITS_RUN, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "cgroup2", "/sys/fs/cgroup", "cgroup2", "nsdelegate,memory_recursiveprot", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_unified_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup2", "/sys/fs/cgroup", "cgroup2", "nsdelegate", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_unified_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup2", "/sys/fs/cgroup", "cgroup2", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_unified_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "tmpfs", "/sys/fs/cgroup", "tmpfs", "mode=0755" TMPFS_LIMITS_SYS_FS_CGROUP, MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, |
| cg_is_legacy_wanted, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", "nsdelegate", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_hybrid_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup2", "/sys/fs/cgroup/unified", "cgroup2", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_hybrid_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd,xattr", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_legacy_wanted, MNT_IN_CONTAINER }, |
| { "cgroup", "/sys/fs/cgroup/systemd", "cgroup", "none,name=systemd", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_legacy_wanted, MNT_FATAL|MNT_IN_CONTAINER }, |
| #if ENABLE_PSTORE |
| { "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_NONE }, |
| #endif |
| #if ENABLE_EFI |
| { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| is_efi_boot, MNT_NONE }, |
| #endif |
| { "bpf", "/sys/fs/bpf", "bpf", "mode=0700", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_NONE, }, |
| }; |
| |
| bool mount_point_is_api(const char *path) { |
| unsigned i; |
| |
| /* Checks if this mount point is considered "API", and hence |
| * should be ignored */ |
| |
| for (i = 0; i < ELEMENTSOF(mount_table); i ++) |
| if (path_equal(path, mount_table[i].where)) |
| return true; |
| |
| return path_startswith(path, "/sys/fs/cgroup/"); |
| } |
| |
| bool mount_point_ignore(const char *path) { |
| /* These are API file systems that might be mounted by other software, we just list them here so that |
| * we know that we should ignore them. */ |
| FOREACH_STRING(i, |
| /* SELinux file systems */ |
| "/sys/fs/selinux", |
| /* Container bind mounts */ |
| "/dev/console", |
| "/proc/kmsg", |
| "/proc/sys", |
| "/proc/sys/kernel/random/boot_id") |
| if (path_equal(path, i)) |
| return true; |
| |
| if (path_startswith(path, "/run/host")) /* All mounts passed in from the container manager are |
| * something we better ignore. */ |
| return true; |
| |
| return false; |
| } |
| |
| static int mount_one(const MountPoint *p, bool relabel) { |
| int r, priority; |
| |
| assert(p); |
| |
| priority = (p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG; |
| |
| if (p->condition_fn && !p->condition_fn()) |
| return 0; |
| |
| /* Relabel first, just in case */ |
| if (relabel) |
| (void) label_fix(p->where, LABEL_IGNORE_ENOENT|LABEL_IGNORE_EROFS); |
| |
| r = path_is_mount_point(p->where, NULL, AT_SYMLINK_FOLLOW); |
| if (r < 0 && r != -ENOENT) { |
| log_full_errno(priority, r, "Failed to determine whether %s is a mount point: %m", p->where); |
| return (p->mode & MNT_FATAL) ? r : 0; |
| } |
| if (r > 0) |
| return 0; |
| |
| /* Skip securityfs in a container */ |
| if (!(p->mode & MNT_IN_CONTAINER) && detect_container() > 0) |
| return 0; |
| |
| /* The access mode here doesn't really matter too much, since |
| * the mounted file system will take precedence anyway. */ |
| if (relabel) |
| (void) mkdir_p_label(p->where, 0755); |
| else |
| (void) mkdir_p(p->where, 0755); |
| |
| log_debug("Mounting %s to %s of type %s with options %s.", |
| p->what, |
| p->where, |
| p->type, |
| strna(p->options)); |
| |
| if (FLAGS_SET(p->mode, MNT_FOLLOW_SYMLINK)) |
| r = RET_NERRNO(mount(p->what, p->where, p->type, p->flags, p->options)); |
| else |
| r = mount_nofollow(p->what, p->where, p->type, p->flags, p->options); |
| if (r < 0) { |
| log_full_errno(priority, r, "Failed to mount %s at %s: %m", p->type, p->where); |
| return (p->mode & MNT_FATAL) ? r : 0; |
| } |
| |
| /* Relabel again, since we now mounted something fresh here */ |
| if (relabel) |
| (void) label_fix(p->where, 0); |
| |
| if (p->mode & MNT_CHECK_WRITABLE) { |
| if (access(p->where, W_OK) < 0) { |
| r = -errno; |
| |
| (void) umount2(p->where, UMOUNT_NOFOLLOW); |
| (void) rmdir(p->where); |
| |
| log_full_errno(priority, r, "Mount point %s not writable after mounting: %m", p->where); |
| return (p->mode & MNT_FATAL) ? r : 0; |
| } |
| } |
| |
| return 1; |
| } |
| |
| static int mount_points_setup(unsigned n, bool loaded_policy) { |
| unsigned i; |
| int r = 0; |
| |
| for (i = 0; i < n; i ++) { |
| int j; |
| |
| j = mount_one(mount_table + i, loaded_policy); |
| if (j != 0 && r >= 0) |
| r = j; |
| } |
| |
| return r; |
| } |
| |
| int mount_setup_early(void) { |
| assert_cc(N_EARLY_MOUNT <= ELEMENTSOF(mount_table)); |
| |
| /* Do a minimal mount of /proc and friends to enable the most |
| * basic stuff, such as SELinux */ |
| return mount_points_setup(N_EARLY_MOUNT, false); |
| } |
| |
| static const char *join_with(const char *controller) { |
| |
| static const char* const pairs[] = { |
| "cpu", "cpuacct", |
| "net_cls", "net_prio", |
| NULL |
| }; |
| |
| assert(controller); |
| |
| /* This will lookup which controller to mount another controller with. Input is a controller name, and output |
| * is the other controller name. The function works both ways: you can input one and get the other, and input |
| * the other to get the one. */ |
| |
| STRV_FOREACH_PAIR(x, y, pairs) { |
| if (streq(controller, *x)) |
| return *y; |
| if (streq(controller, *y)) |
| return *x; |
| } |
| |
| return NULL; |
| } |
| |
| static int symlink_controller(const char *target, const char *alias) { |
| const char *a; |
| int r; |
| |
| assert(target); |
| assert(alias); |
| |
| a = strjoina("/sys/fs/cgroup/", alias); |
| |
| r = symlink_idempotent(target, a, false); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create symlink %s: %m", a); |
| |
| #if HAVE_SMACK_RUN_LABEL |
| const char *p; |
| |
| p = strjoina("/sys/fs/cgroup/", target); |
| |
| r = mac_smack_copy(a, p); |
| if (r < 0 && r != -EOPNOTSUPP) |
| return log_error_errno(r, "Failed to copy smack label from %s to %s: %m", p, a); |
| #endif |
| |
| return 0; |
| } |
| |
| int mount_cgroup_controllers(void) { |
| _cleanup_set_free_ Set *controllers = NULL; |
| int r; |
| |
| if (!cg_is_legacy_wanted()) |
| return 0; |
| |
| /* Mount all available cgroup controllers that are built into the kernel. */ |
| r = cg_kernel_controllers(&controllers); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enumerate cgroup controllers: %m"); |
| |
| for (;;) { |
| _cleanup_free_ char *options = NULL, *controller = NULL, *where = NULL; |
| const char *other_controller; |
| MountPoint p = { |
| .what = "cgroup", |
| .type = "cgroup", |
| .flags = MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| .mode = MNT_IN_CONTAINER, |
| }; |
| |
| controller = set_steal_first(controllers); |
| if (!controller) |
| break; |
| |
| /* Check if we shall mount this together with another controller */ |
| other_controller = join_with(controller); |
| if (other_controller) { |
| _cleanup_free_ char *c = NULL; |
| |
| /* Check if the other controller is actually available in the kernel too */ |
| c = set_remove(controllers, other_controller); |
| if (c) { |
| |
| /* Join the two controllers into one string, and maintain a stable ordering */ |
| if (strcmp(controller, other_controller) < 0) |
| options = strjoin(controller, ",", other_controller); |
| else |
| options = strjoin(other_controller, ",", controller); |
| if (!options) |
| return log_oom(); |
| } |
| } |
| |
| /* The simple case, where there's only one controller to mount together */ |
| if (!options) |
| options = TAKE_PTR(controller); |
| |
| where = path_join("/sys/fs/cgroup", options); |
| if (!where) |
| return log_oom(); |
| |
| p.where = where; |
| p.options = options; |
| |
| r = mount_one(&p, true); |
| if (r < 0) |
| return r; |
| |
| /* Create symlinks from the individual controller names, in case we have a joined mount */ |
| if (controller) |
| (void) symlink_controller(options, controller); |
| if (other_controller) |
| (void) symlink_controller(options, other_controller); |
| } |
| |
| /* Now that we mounted everything, let's make the tmpfs the cgroup file systems are mounted into read-only. */ |
| (void) mount_nofollow("tmpfs", "/sys/fs/cgroup", "tmpfs", |
| MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, |
| "mode=0755" TMPFS_LIMITS_SYS_FS_CGROUP); |
| |
| return 0; |
| } |
| |
| #if HAVE_SELINUX || ENABLE_SMACK |
| static int relabel_cb( |
| RecurseDirEvent event, |
| const char *path, |
| int dir_fd, |
| int inode_fd, |
| const struct dirent *de, |
| const struct statx *sx, |
| void *userdata) { |
| |
| switch (event) { |
| |
| case RECURSE_DIR_LEAVE: |
| case RECURSE_DIR_SKIP_MOUNT: |
| /* If we already saw this dirent when entering it or this is a dirent that on a different |
| * mount, don't relabel it. */ |
| return RECURSE_DIR_CONTINUE; |
| |
| case RECURSE_DIR_ENTER: |
| /* /run/initramfs is static data and big, no need to dynamically relabel its contents at boot... */ |
| if (path_equal(path, "/run/initramfs")) |
| return RECURSE_DIR_SKIP_ENTRY; |
| |
| _fallthrough_; |
| |
| default: |
| /* Otherwise, label it, even if we had trouble stat()ing it and similar. SELinux can figure this out */ |
| (void) label_fix(path, 0); |
| return RECURSE_DIR_CONTINUE; |
| } |
| } |
| |
| static int relabel_tree(const char *path) { |
| int r; |
| |
| r = recurse_dir_at(AT_FDCWD, path, 0, UINT_MAX, RECURSE_DIR_ENSURE_TYPE|RECURSE_DIR_SAME_MOUNT, relabel_cb, NULL); |
| if (r < 0) |
| log_debug_errno(r, "Failed to recursively relabel '%s': %m", path); |
| |
| return r; |
| } |
| |
| static int relabel_cgroup_filesystems(void) { |
| int r; |
| struct statfs st; |
| |
| r = cg_all_unified(); |
| if (r == 0) { |
| /* Temporarily remount the root cgroup filesystem to give it a proper label. Do this |
| only when the filesystem has been already populated by a previous instance of systemd |
| running from initrd. Otherwise don't remount anything and leave the filesystem read-write |
| for the cgroup filesystems to be mounted inside. */ |
| if (statfs("/sys/fs/cgroup", &st) < 0) |
| return log_error_errno(errno, "Failed to determine mount flags for /sys/fs/cgroup: %m"); |
| |
| if (st.f_flags & ST_RDONLY) |
| (void) mount_nofollow(NULL, "/sys/fs/cgroup", NULL, MS_REMOUNT, NULL); |
| |
| (void) label_fix("/sys/fs/cgroup", 0); |
| (void) relabel_tree("/sys/fs/cgroup"); |
| |
| if (st.f_flags & ST_RDONLY) |
| (void) mount_nofollow(NULL, "/sys/fs/cgroup", NULL, MS_REMOUNT|MS_RDONLY, NULL); |
| |
| } else if (r < 0) |
| return log_error_errno(r, "Failed to determine whether we are in all unified mode: %m"); |
| |
| return 0; |
| } |
| |
| static int relabel_extra(void) { |
| _cleanup_strv_free_ char **files = NULL; |
| int r, c = 0; |
| |
| /* Support for relabelling additional files or directories after loading the policy. For this, code in the |
| * initrd simply has to drop in *.relabel files into /run/systemd/relabel-extra.d/. We'll read all such files |
| * expecting one absolute path by line and will relabel each (and everyone below that in case the path refers |
| * to a directory). These drop-in files are supposed to be absolutely minimal, and do not understand comments |
| * and such. After the operation succeeded the files are removed, and the drop-in directory as well, if |
| * possible. |
| */ |
| |
| r = conf_files_list(&files, ".relabel", NULL, |
| CONF_FILES_FILTER_MASKED | CONF_FILES_REGULAR, |
| "/run/systemd/relabel-extra.d/"); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enumerate /run/systemd/relabel-extra.d/, ignoring: %m"); |
| |
| STRV_FOREACH(file, files) { |
| _cleanup_fclose_ FILE *f = NULL; |
| |
| f = fopen(*file, "re"); |
| if (!f) { |
| log_warning_errno(errno, "Failed to open %s, ignoring: %m", *file); |
| continue; |
| } |
| |
| for (;;) { |
| _cleanup_free_ char *line = NULL; |
| |
| r = read_line(f, LONG_LINE_MAX, &line); |
| if (r < 0) { |
| log_warning_errno(r, "Failed to read %s, ignoring: %m", *file); |
| break; |
| } |
| if (r == 0) /* EOF */ |
| break; |
| |
| path_simplify(line); |
| |
| if (!path_is_normalized(line)) { |
| log_warning("Path to relabel is not normalized, ignoring: %s", line); |
| continue; |
| } |
| |
| if (!path_is_absolute(line)) { |
| log_warning("Path to relabel is not absolute, ignoring: %s", line); |
| continue; |
| } |
| |
| log_debug("Relabelling additional file/directory '%s'.", line); |
| (void) label_fix(line, 0); |
| (void) relabel_tree(line); |
| c++; |
| } |
| |
| if (unlink(*file) < 0) |
| log_warning_errno(errno, "Failed to remove %s, ignoring: %m", *file); |
| } |
| |
| /* Remove when we complete things. */ |
| if (rmdir("/run/systemd/relabel-extra.d") < 0 && |
| errno != ENOENT) |
| log_warning_errno(errno, "Failed to remove /run/systemd/relabel-extra.d/ directory: %m"); |
| |
| return c; |
| } |
| #endif |
| |
| int mount_setup(bool loaded_policy, bool leave_propagation) { |
| int r; |
| |
| r = mount_points_setup(ELEMENTSOF(mount_table), loaded_policy); |
| if (r < 0) |
| return r; |
| |
| #if HAVE_SELINUX || ENABLE_SMACK |
| /* Nodes in devtmpfs and /run need to be manually updated for |
| * the appropriate labels, after mounting. The other virtual |
| * API file systems like /sys and /proc do not need that, they |
| * use the same label for all their files. */ |
| if (loaded_policy) { |
| usec_t before_relabel, after_relabel; |
| int n_extra; |
| |
| before_relabel = now(CLOCK_MONOTONIC); |
| |
| FOREACH_STRING(i, "/dev", "/dev/shm", "/run") |
| (void) relabel_tree(i); |
| |
| (void) relabel_cgroup_filesystems(); |
| |
| n_extra = relabel_extra(); |
| |
| after_relabel = now(CLOCK_MONOTONIC); |
| |
| log_info("Relabelled /dev, /dev/shm, /run, /sys/fs/cgroup%s in %s.", |
| n_extra > 0 ? ", additional files" : "", |
| FORMAT_TIMESPAN(after_relabel - before_relabel, 0)); |
| } |
| #endif |
| |
| /* Create a few default symlinks, which are normally created |
| * by udevd, but some scripts might need them before we start |
| * udevd. */ |
| dev_setup(NULL, UID_INVALID, GID_INVALID); |
| |
| /* Mark the root directory as shared in regards to mount propagation. The kernel defaults to "private", but we |
| * think it makes more sense to have a default of "shared" so that nspawn and the container tools work out of |
| * the box. If specific setups need other settings they can reset the propagation mode to private if |
| * needed. Note that we set this only when we are invoked directly by the kernel. If we are invoked by a |
| * container manager we assume the container manager knows what it is doing (for example, because it set up |
| * some directories with different propagation modes). */ |
| if (detect_container() <= 0 && !leave_propagation) |
| if (mount(NULL, "/", NULL, MS_REC|MS_SHARED, NULL) < 0) |
| log_warning_errno(errno, "Failed to set up the root directory for shared mount propagation: %m"); |
| |
| /* Create a few directories we always want around, Note that sd_booted() checks for /run/systemd/system, so |
| * this mkdir really needs to stay for good, otherwise software that copied sd-daemon.c into their sources will |
| * misdetect systemd. */ |
| (void) mkdir_label("/run/systemd", 0755); |
| (void) mkdir_label("/run/systemd/system", 0755); |
| |
| /* Make sure we have a mount point to hide in sandboxes */ |
| (void) mkdir_label("/run/credentials", 0755); |
| |
| /* Also create /run/systemd/inaccessible nodes, so that we always have something to mount |
| * inaccessible nodes from. If we run in a container the host might have created these for us already |
| * in /run/host/inaccessible/. Use those if we can, since that way we likely get access to block/char |
| * device nodes that are inaccessible, and if userns is used to nodes that are on mounts owned by a |
| * userns outside the container and thus nicely read-only and not remountable. */ |
| if (access("/run/host/inaccessible/", F_OK) < 0) { |
| if (errno != ENOENT) |
| log_debug_errno(errno, "Failed to check if /run/host/inaccessible exists, ignoring: %m"); |
| |
| (void) make_inaccessible_nodes("/run/systemd", UID_INVALID, GID_INVALID); |
| } else |
| (void) symlink("../host/inaccessible", "/run/systemd/inaccessible"); |
| |
| return 0; |
| } |
