| /* SPDX-License-Identifier: LGPL-2.1+ */ |
| /*** |
| This file is part of systemd. |
| |
| Copyright 2010 Lennart Poettering |
| |
| systemd is free software; you can redistribute it and/or modify it |
| under the terms of the GNU Lesser General Public License as published by |
| the Free Software Foundation; either version 2.1 of the License, or |
| (at your option) any later version. |
| |
| systemd is distributed in the hope that it will be useful, but |
| WITHOUT ANY WARRANTY; without even the implied warranty of |
| MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| Lesser General Public License for more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with systemd; If not, see <http://www.gnu.org/licenses/>. |
| ***/ |
| |
| #include <errno.h> |
| #include <ftw.h> |
| #include <stdlib.h> |
| #include <sys/mount.h> |
| #include <unistd.h> |
| |
| #include "alloc-util.h" |
| #include "bus-util.h" |
| #include "cgroup-util.h" |
| #include "dev-setup.h" |
| #include "efivars.h" |
| #include "fileio.h" |
| #include "fs-util.h" |
| #include "label.h" |
| #include "log.h" |
| #include "macro.h" |
| #include "missing.h" |
| #include "mkdir.h" |
| #include "mount-setup.h" |
| #include "mount-util.h" |
| #include "path-util.h" |
| #include "set.h" |
| #include "smack-util.h" |
| #include "strv.h" |
| #include "user-util.h" |
| #include "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, |
| } 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[] = { |
| { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "devtmpfs", "/dev", "devtmpfs", "mode=755", 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=1777,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| mac_smack_use, MNT_FATAL }, |
| #endif |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "devpts", "/dev/pts", "devpts", "mode=620,gid=" STRINGIFY(TTY_GID), MS_NOSUID|MS_NOEXEC, |
| NULL, MNT_IN_CONTAINER }, |
| #if ENABLE_SMACK |
| { "tmpfs", "/run", "tmpfs", "mode=755,smackfsroot=*", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| mac_smack_use, MNT_FATAL }, |
| #endif |
| { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| NULL, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "cgroup", "/sys/fs/cgroup", "cgroup2", "nsdelegate", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_unified_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup", "/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=755", MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, |
| cg_is_legacy_wanted, MNT_FATAL|MNT_IN_CONTAINER }, |
| { "cgroup", "/sys/fs/cgroup/unified", "cgroup2", "nsdelegate", MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| cg_is_hybrid_wanted, MNT_IN_CONTAINER|MNT_CHECK_WRITABLE }, |
| { "cgroup", "/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 }, |
| { "pstore", "/sys/fs/pstore", "pstore", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| NULL, MNT_NONE }, |
| #if ENABLE_EFI |
| { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| is_efi_boot, MNT_NONE }, |
| #endif |
| }; |
| |
| /* 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 */ |
| |
| static const char ignore_paths[] = |
| /* SELinux file systems */ |
| "/sys/fs/selinux\0" |
| /* Container bind mounts */ |
| "/proc/sys\0" |
| "/dev/console\0" |
| "/proc/kmsg\0"; |
| |
| 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) { |
| const char *i; |
| |
| NULSTR_FOREACH(i, ignore_paths) |
| if (path_equal(path, i)) |
| 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, true, true); |
| |
| 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 (mount(p->what, |
| p->where, |
| p->type, |
| p->flags, |
| p->options) < 0) { |
| log_full_errno(priority, errno, "Failed to mount %s at %s: %m", p->type, p->where); |
| return (p->mode & MNT_FATAL) ? -errno : 0; |
| } |
| |
| /* Relabel again, since we now mounted something fresh here */ |
| if (relabel) |
| (void) label_fix(p->where, false, false); |
| |
| if (p->mode & MNT_CHECK_WRITABLE) { |
| if (access(p->where, W_OK) < 0) { |
| r = -errno; |
| |
| (void) umount(p->where); |
| (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); |
| } |
| |
| int mount_cgroup_controllers(char ***join_controllers) { |
| _cleanup_set_free_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; |
| MountPoint p = { |
| .what = "cgroup", |
| .type = "cgroup", |
| .flags = MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| .mode = MNT_IN_CONTAINER, |
| }; |
| char ***k = NULL; |
| |
| controller = set_steal_first(controllers); |
| if (!controller) |
| break; |
| |
| if (join_controllers) |
| for (k = join_controllers; *k; k++) |
| if (strv_find(*k, controller)) |
| break; |
| |
| if (k && *k) { |
| char **i, **j; |
| |
| for (i = *k, j = *k; *i; i++) { |
| |
| if (!streq(*i, controller)) { |
| _cleanup_free_ char *t; |
| |
| t = set_remove(controllers, *i); |
| if (!t) { |
| free(*i); |
| continue; |
| } |
| } |
| |
| *(j++) = *i; |
| } |
| |
| *j = NULL; |
| |
| options = strv_join(*k, ","); |
| if (!options) |
| return log_oom(); |
| } else { |
| options = controller; |
| controller = NULL; |
| } |
| |
| where = strappend("/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; |
| |
| if (r > 0 && k && *k) { |
| char **i; |
| |
| for (i = *k; *i; i++) { |
| _cleanup_free_ char *t = NULL; |
| |
| t = strappend("/sys/fs/cgroup/", *i); |
| if (!t) |
| return log_oom(); |
| |
| r = symlink(options, t); |
| if (r >= 0) { |
| #ifdef SMACK_RUN_LABEL |
| _cleanup_free_ char *src; |
| src = strappend("/sys/fs/cgroup/", options); |
| if (!src) |
| return log_oom(); |
| r = mac_smack_copy(t, src); |
| if (r < 0 && r != -EOPNOTSUPP) |
| return log_error_errno(r, "Failed to copy smack label from %s to %s: %m", src, t); |
| #endif |
| } else if (errno != EEXIST) |
| return log_error_errno(errno, "Failed to create symlink %s: %m", t); |
| } |
| } |
| } |
| |
| /* Now that we mounted everything, let's make the tmpfs the |
| * cgroup file systems are mounted into read-only. */ |
| (void) mount("tmpfs", "/sys/fs/cgroup", "tmpfs", MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); |
| |
| return 0; |
| } |
| |
| #if HAVE_SELINUX || ENABLE_SMACK |
| static int nftw_cb( |
| const char *fpath, |
| const struct stat *sb, |
| int tflag, |
| struct FTW *ftwbuf) { |
| |
| /* No need to label /dev twice in a row... */ |
| if (_unlikely_(ftwbuf->level == 0)) |
| return FTW_CONTINUE; |
| |
| label_fix(fpath, false, false); |
| |
| /* /run/initramfs is static data and big, no need to |
| * dynamically relabel its contents at boot... */ |
| if (_unlikely_(ftwbuf->level == 1 && |
| tflag == FTW_D && |
| streq(fpath, "/run/initramfs"))) |
| return FTW_SKIP_SUBTREE; |
| |
| return FTW_CONTINUE; |
| }; |
| #endif |
| |
| int mount_setup(bool loaded_policy) { |
| int r = 0; |
| |
| 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; |
| char timespan[FORMAT_TIMESPAN_MAX]; |
| |
| before_relabel = now(CLOCK_MONOTONIC); |
| |
| nftw("/dev", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); |
| nftw("/dev/shm", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); |
| nftw("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); |
| |
| /* Temporarily remount the root cgroup filesystem to give it a proper label. */ |
| r = cg_all_unified(); |
| if (r == 0) { |
| (void) mount(NULL, "/sys/fs/cgroup", NULL, MS_REMOUNT, NULL); |
| label_fix("/sys/fs/cgroup", false, false); |
| nftw("/sys/fs/cgroup", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); |
| (void) mount(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"); |
| |
| after_relabel = now(CLOCK_MONOTONIC); |
| |
| log_info("Relabelled /dev, /run and /sys/fs/cgroup in %s.", |
| format_timespan(timespan, sizeof(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) |
| 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); |
| |
| /* Set up inaccessible items */ |
| (void) mkdir_label("/run/systemd/inaccessible", 0000); |
| (void) mknod("/run/systemd/inaccessible/reg", S_IFREG | 0000, 0); |
| (void) mkdir_label("/run/systemd/inaccessible/dir", 0000); |
| (void) mknod("/run/systemd/inaccessible/chr", S_IFCHR | 0000, makedev(0, 0)); |
| (void) mknod("/run/systemd/inaccessible/blk", S_IFBLK | 0000, makedev(0, 0)); |
| (void) mkfifo("/run/systemd/inaccessible/fifo", 0000); |
| (void) mknod("/run/systemd/inaccessible/sock", S_IFSOCK | 0000, 0); |
| |
| return 0; |
| } |