| /* SPDX-License-Identifier: LGPL-2.1-or-later */ |
| |
| #include <sys/mount.h> |
| #include <linux/magic.h> |
| |
| #include "alloc-util.h" |
| #include "chase-symlinks.h" |
| #include "escape.h" |
| #include "fd-util.h" |
| #include "format-util.h" |
| #include "fs-util.h" |
| #include "label.h" |
| #include "mkdir-label.h" |
| #include "mount-util.h" |
| #include "mountpoint-util.h" |
| #include "namespace-util.h" |
| #include "nspawn-mount.h" |
| #include "parse-util.h" |
| #include "path-util.h" |
| #include "rm-rf.h" |
| #include "set.h" |
| #include "sort-util.h" |
| #include "stat-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "tmpfile-util.h" |
| #include "user-util.h" |
| |
| CustomMount* custom_mount_add(CustomMount **l, size_t *n, CustomMountType t) { |
| CustomMount *c, *ret; |
| |
| assert(l); |
| assert(n); |
| assert(t >= 0); |
| assert(t < _CUSTOM_MOUNT_TYPE_MAX); |
| |
| c = reallocarray(*l, *n + 1, sizeof(CustomMount)); |
| if (!c) |
| return NULL; |
| |
| *l = c; |
| ret = *l + *n; |
| (*n)++; |
| |
| *ret = (CustomMount) { |
| .type = t |
| }; |
| |
| return ret; |
| } |
| |
| void custom_mount_free_all(CustomMount *l, size_t n) { |
| for (size_t i = 0; i < n; i++) { |
| CustomMount *m = l + i; |
| |
| free(m->source); |
| free(m->destination); |
| free(m->options); |
| |
| if (m->work_dir) { |
| (void) rm_rf(m->work_dir, REMOVE_ROOT|REMOVE_PHYSICAL); |
| free(m->work_dir); |
| } |
| |
| if (m->rm_rf_tmpdir) { |
| (void) rm_rf(m->rm_rf_tmpdir, REMOVE_ROOT|REMOVE_PHYSICAL); |
| free(m->rm_rf_tmpdir); |
| } |
| |
| strv_free(m->lower); |
| free(m->type_argument); |
| } |
| |
| free(l); |
| } |
| |
| static int custom_mount_compare(const CustomMount *a, const CustomMount *b) { |
| int r; |
| |
| r = path_compare(a->destination, b->destination); |
| if (r != 0) |
| return r; |
| |
| return CMP(a->type, b->type); |
| } |
| |
| static int source_path_parse(const char *p, char **ret) { |
| assert(p); |
| assert(ret); |
| |
| if (isempty(p)) |
| return -EINVAL; |
| |
| if (*p == '+') { |
| if (!path_is_absolute(p + 1)) |
| return -EINVAL; |
| |
| char *s = strdup(p); |
| if (!s) |
| return -ENOMEM; |
| |
| *ret = TAKE_PTR(s); |
| return 0; |
| } |
| |
| return path_make_absolute_cwd(p, ret); |
| } |
| |
| static int source_path_parse_nullable(const char *p, char **ret) { |
| assert(p); |
| assert(ret); |
| |
| if (isempty(p)) { |
| *ret = NULL; |
| return 0; |
| } |
| |
| return source_path_parse(p, ret); |
| } |
| |
| static char *resolve_source_path(const char *dest, const char *source) { |
| if (!source) |
| return NULL; |
| |
| if (source[0] == '+') |
| return path_join(dest, source + 1); |
| |
| return strdup(source); |
| } |
| |
| static int allocate_temporary_source(CustomMount *m) { |
| assert(m); |
| assert(!m->source); |
| assert(!m->rm_rf_tmpdir); |
| |
| m->rm_rf_tmpdir = strdup("/var/tmp/nspawn-temp-XXXXXX"); |
| if (!m->rm_rf_tmpdir) |
| return log_oom(); |
| |
| if (!mkdtemp(m->rm_rf_tmpdir)) { |
| m->rm_rf_tmpdir = mfree(m->rm_rf_tmpdir); |
| return log_error_errno(errno, "Failed to acquire temporary directory: %m"); |
| } |
| |
| m->source = path_join(m->rm_rf_tmpdir, "src"); |
| if (!m->source) |
| return log_oom(); |
| |
| if (mkdir(m->source, 0755) < 0) |
| return log_error_errno(errno, "Failed to create %s: %m", m->source); |
| |
| return 0; |
| } |
| |
| int custom_mount_prepare_all(const char *dest, CustomMount *l, size_t n) { |
| int r; |
| |
| /* Prepare all custom mounts. This will make source we know all temporary directories. This is called in the |
| * parent process, so that we know the temporary directories to remove on exit before we fork off the |
| * children. */ |
| |
| assert(l || n == 0); |
| |
| /* Order the custom mounts, and make sure we have a working directory */ |
| typesafe_qsort(l, n, custom_mount_compare); |
| |
| for (size_t i = 0; i < n; i++) { |
| CustomMount *m = l + i; |
| |
| /* /proc we mount in the inner child, i.e. when we acquired CLONE_NEWPID. All other mounts we mount |
| * already in the outer child, so that the mounts are already established before CLONE_NEWPID and in |
| * particular CLONE_NEWUSER. This also means any custom mounts below /proc also need to be mounted in |
| * the inner child, not the outer one. Determine this here. */ |
| m->in_userns = path_startswith(m->destination, "/proc"); |
| |
| if (m->type == CUSTOM_MOUNT_BIND) { |
| if (m->source) { |
| char *s; |
| |
| s = resolve_source_path(dest, m->source); |
| if (!s) |
| return log_oom(); |
| |
| free_and_replace(m->source, s); |
| } else { |
| /* No source specified? In that case, use a throw-away temporary directory in /var/tmp */ |
| |
| r = allocate_temporary_source(m); |
| if (r < 0) |
| return r; |
| } |
| } |
| |
| if (m->type == CUSTOM_MOUNT_OVERLAY) { |
| STRV_FOREACH(j, m->lower) { |
| char *s; |
| |
| s = resolve_source_path(dest, *j); |
| if (!s) |
| return log_oom(); |
| |
| free_and_replace(*j, s); |
| } |
| |
| if (m->source) { |
| char *s; |
| |
| s = resolve_source_path(dest, m->source); |
| if (!s) |
| return log_oom(); |
| |
| free_and_replace(m->source, s); |
| } else { |
| r = allocate_temporary_source(m); |
| if (r < 0) |
| return r; |
| } |
| |
| if (m->work_dir) { |
| char *s; |
| |
| s = resolve_source_path(dest, m->work_dir); |
| if (!s) |
| return log_oom(); |
| |
| free_and_replace(m->work_dir, s); |
| } else { |
| r = tempfn_random(m->source, NULL, &m->work_dir); |
| if (r < 0) |
| return log_error_errno(r, "Failed to acquire working directory: %m"); |
| } |
| |
| (void) mkdir_label(m->work_dir, 0700); |
| } |
| } |
| |
| return 0; |
| } |
| |
| int bind_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
| _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL, *p = NULL; |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| |
| r = extract_many_words(&s, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| if (r == 1) { |
| destination = strdup(source[0] == '+' ? source+1 : source); |
| if (!destination) |
| return -ENOMEM; |
| } |
| if (r == 2 && !isempty(s)) { |
| opts = strdup(s); |
| if (!opts) |
| return -ENOMEM; |
| } |
| |
| r = source_path_parse_nullable(source, &p); |
| if (r < 0) |
| return r; |
| |
| if (!path_is_absolute(destination)) |
| return -EINVAL; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); |
| if (!m) |
| return -ENOMEM; |
| |
| m->source = TAKE_PTR(p); |
| m->destination = TAKE_PTR(destination); |
| m->read_only = read_only; |
| m->options = TAKE_PTR(opts); |
| |
| return 0; |
| } |
| |
| int tmpfs_mount_parse(CustomMount **l, size_t *n, const char *s) { |
| _cleanup_free_ char *path = NULL, *opts = NULL; |
| const char *p = ASSERT_PTR(s); |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| |
| r = extract_first_word(&p, &path, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| |
| if (isempty(p)) |
| opts = strdup("mode=0755"); |
| else |
| opts = strdup(p); |
| if (!opts) |
| return -ENOMEM; |
| |
| if (!path_is_absolute(path)) |
| return -EINVAL; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_TMPFS); |
| if (!m) |
| return -ENOMEM; |
| |
| m->destination = TAKE_PTR(path); |
| m->options = TAKE_PTR(opts); |
| |
| return 0; |
| } |
| |
| int overlay_mount_parse(CustomMount **l, size_t *n, const char *s, bool read_only) { |
| _cleanup_free_ char *upper = NULL, *destination = NULL; |
| _cleanup_strv_free_ char **lower = NULL; |
| CustomMount *m; |
| int r, k; |
| |
| k = strv_split_full(&lower, s, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
| if (k < 0) |
| return k; |
| if (k < 2) |
| return -EADDRNOTAVAIL; |
| if (k == 2) { |
| _cleanup_free_ char *p = NULL; |
| |
| /* If two parameters are specified, the first one is the lower, the second one the upper directory. And |
| * we'll also define the destination mount point the same as the upper. */ |
| |
| r = source_path_parse(lower[0], &p); |
| if (r < 0) |
| return r; |
| |
| free_and_replace(lower[0], p); |
| |
| r = source_path_parse(lower[1], &p); |
| if (r < 0) |
| return r; |
| |
| free_and_replace(lower[1], p); |
| |
| upper = TAKE_PTR(lower[1]); |
| |
| destination = strdup(upper[0] == '+' ? upper+1 : upper); /* take the destination without "+" prefix */ |
| if (!destination) |
| return -ENOMEM; |
| } else { |
| _cleanup_free_ char *p = NULL; |
| |
| /* If more than two parameters are specified, the last one is the destination, the second to last one |
| * the "upper", and all before that the "lower" directories. */ |
| |
| destination = lower[k - 1]; |
| upper = TAKE_PTR(lower[k - 2]); |
| |
| STRV_FOREACH(i, lower) { |
| r = source_path_parse(*i, &p); |
| if (r < 0) |
| return r; |
| |
| free_and_replace(*i, p); |
| } |
| |
| /* If the upper directory is unspecified, then let's create it automatically as a throw-away directory |
| * in /var/tmp */ |
| r = source_path_parse_nullable(upper, &p); |
| if (r < 0) |
| return r; |
| |
| free_and_replace(upper, p); |
| |
| if (!path_is_absolute(destination)) |
| return -EINVAL; |
| } |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_OVERLAY); |
| if (!m) |
| return -ENOMEM; |
| |
| m->destination = TAKE_PTR(destination); |
| m->source = TAKE_PTR(upper); |
| m->lower = TAKE_PTR(lower); |
| m->read_only = read_only; |
| |
| return 0; |
| } |
| |
| int inaccessible_mount_parse(CustomMount **l, size_t *n, const char *s) { |
| _cleanup_free_ char *path = NULL; |
| CustomMount *m; |
| |
| assert(l); |
| assert(n); |
| assert(s); |
| |
| if (!path_is_absolute(s)) |
| return -EINVAL; |
| |
| path = strdup(s); |
| if (!path) |
| return -ENOMEM; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_INACCESSIBLE); |
| if (!m) |
| return -ENOMEM; |
| |
| m->destination = TAKE_PTR(path); |
| return 0; |
| } |
| |
| int tmpfs_patch_options( |
| const char *options, |
| uid_t uid_shift, |
| const char *selinux_apifs_context, |
| char **ret) { |
| |
| _cleanup_free_ char *buf = NULL; |
| |
| assert(ret); |
| |
| if (options) { |
| buf = strdup(options); |
| if (!buf) |
| return -ENOMEM; |
| } |
| |
| if (uid_shift != UID_INVALID) |
| if (strextendf_with_separator(&buf, ",", "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift) < 0) |
| return -ENOMEM; |
| |
| #if HAVE_SELINUX |
| if (selinux_apifs_context) |
| if (strextendf_with_separator(&buf, ",", "context=\"%s\"", selinux_apifs_context) < 0) |
| return -ENOMEM; |
| #endif |
| |
| *ret = TAKE_PTR(buf); |
| return !!*ret; |
| } |
| |
| int mount_sysfs(const char *dest, MountSettingsMask mount_settings) { |
| const char *full, *top; |
| int r; |
| unsigned long extra_flags = 0; |
| |
| top = prefix_roota(dest, "/sys"); |
| r = path_is_fs_type(top, SYSFS_MAGIC); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine filesystem type of %s: %m", top); |
| /* /sys might already be mounted as sysfs by the outer child in the |
| * !netns case. In this case, it's all good. Don't touch it because we |
| * don't have the right to do so, see https://github.com/systemd/systemd/issues/1555. |
| */ |
| if (r > 0) |
| return 0; |
| |
| full = prefix_roota(top, "/full"); |
| |
| (void) mkdir(full, 0755); |
| |
| if (FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO)) |
| extra_flags |= MS_RDONLY; |
| |
| r = mount_nofollow_verbose(LOG_ERR, "sysfs", full, "sysfs", |
| MS_NOSUID|MS_NOEXEC|MS_NODEV|extra_flags, NULL); |
| if (r < 0) |
| return r; |
| |
| FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { |
| _cleanup_free_ char *from = NULL, *to = NULL; |
| |
| from = path_join(full, x); |
| if (!from) |
| return log_oom(); |
| |
| to = path_join(top, x); |
| if (!to) |
| return log_oom(); |
| |
| (void) mkdir(to, 0755); |
| |
| r = mount_nofollow_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL); |
| if (r < 0) |
| return r; |
| |
| r = mount_nofollow_verbose(LOG_ERR, NULL, to, NULL, |
| MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| r = umount_verbose(LOG_ERR, full, UMOUNT_NOFOLLOW); |
| if (r < 0) |
| return r; |
| |
| if (rmdir(full) < 0) |
| return log_error_errno(errno, "Failed to remove %s: %m", full); |
| |
| /* Create mountpoint for cgroups. Otherwise we are not allowed since we |
| * remount /sys read-only. |
| */ |
| const char *x = prefix_roota(top, "/fs/cgroup"); |
| (void) mkdir_p(x, 0755); |
| |
| return mount_nofollow_verbose(LOG_ERR, NULL, top, NULL, |
| MS_BIND|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT|extra_flags, NULL); |
| } |
| |
| #define PROC_DEFAULT_MOUNT_FLAGS (MS_NOSUID|MS_NOEXEC|MS_NODEV) |
| #define SYS_DEFAULT_MOUNT_FLAGS (MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV) |
| |
| int mount_all(const char *dest, |
| MountSettingsMask mount_settings, |
| uid_t uid_shift, |
| const char *selinux_apifs_context) { |
| |
| #define PROC_INACCESSIBLE_REG(path) \ |
| { "/run/systemd/inaccessible/reg", (path), NULL, NULL, MS_BIND, \ |
| MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ |
| { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ |
| MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ |
| |
| #define PROC_READ_ONLY(path) \ |
| { (path), (path), NULL, NULL, MS_BIND, \ |
| MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ \ |
| { NULL, (path), NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, \ |
| MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO } /* Then, make it r/o */ |
| |
| typedef struct MountPoint { |
| const char *what; |
| const char *where; |
| const char *type; |
| const char *options; |
| unsigned long flags; |
| MountSettingsMask mount_settings; |
| } MountPoint; |
| |
| static const MountPoint mount_table[] = { |
| /* First we list inner child mounts (i.e. mounts applied *after* entering user namespacing) */ |
| { "proc", "/proc", "proc", NULL, PROC_DEFAULT_MOUNT_FLAGS, |
| MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_MKDIR|MOUNT_FOLLOW_SYMLINKS }, /* we follow symlinks here since not following them requires /proc/ already being mounted, which we don't have here. */ |
| |
| { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, |
| MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* Bind mount first ... */ |
| |
| { "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, |
| MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO|MOUNT_APPLY_APIVFS_NETNS }, /* (except for this) */ |
| |
| { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, |
| MOUNT_FATAL|MOUNT_IN_USERNS|MOUNT_APPLY_APIVFS_RO }, /* ... then, make it r/o */ |
| |
| /* Make these files inaccessible to container payloads: they potentially leak information about kernel |
| * internals or the host's execution environment to the container */ |
| PROC_INACCESSIBLE_REG("/proc/kallsyms"), |
| PROC_INACCESSIBLE_REG("/proc/kcore"), |
| PROC_INACCESSIBLE_REG("/proc/keys"), |
| PROC_INACCESSIBLE_REG("/proc/sysrq-trigger"), |
| PROC_INACCESSIBLE_REG("/proc/timer_list"), |
| |
| /* Make these directories read-only to container payloads: they show hardware information, and in some |
| * cases contain tunables the container really shouldn't have access to. */ |
| PROC_READ_ONLY("/proc/acpi"), |
| PROC_READ_ONLY("/proc/apm"), |
| PROC_READ_ONLY("/proc/asound"), |
| PROC_READ_ONLY("/proc/bus"), |
| PROC_READ_ONLY("/proc/fs"), |
| PROC_READ_ONLY("/proc/irq"), |
| PROC_READ_ONLY("/proc/scsi"), |
| |
| { "mqueue", "/dev/mqueue", "mqueue", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| MOUNT_IN_USERNS|MOUNT_MKDIR }, |
| |
| /* Then we list outer child mounts (i.e. mounts applied *before* entering user namespacing) */ |
| { "tmpfs", "/tmp", "tmpfs", "mode=01777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| MOUNT_FATAL|MOUNT_APPLY_TMPFS_TMP|MOUNT_MKDIR }, |
| { "tmpfs", "/sys", "tmpfs", "mode=0555" TMPFS_LIMITS_SYS, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| MOUNT_FATAL|MOUNT_APPLY_APIVFS_NETNS|MOUNT_MKDIR }, |
| { "sysfs", "/sys", "sysfs", NULL, SYS_DEFAULT_MOUNT_FLAGS, |
| MOUNT_FATAL|MOUNT_APPLY_APIVFS_RO|MOUNT_MKDIR }, /* skipped if above was mounted */ |
| { "sysfs", "/sys", "sysfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, |
| MOUNT_FATAL|MOUNT_MKDIR }, /* skipped if above was mounted */ |
| { "tmpfs", "/dev", "tmpfs", "mode=0755" TMPFS_LIMITS_PRIVATE_DEV, MS_NOSUID|MS_STRICTATIME, |
| MOUNT_FATAL|MOUNT_MKDIR }, |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=01777" NESTED_TMPFS_LIMITS, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| MOUNT_FATAL|MOUNT_MKDIR }, |
| { "tmpfs", "/run", "tmpfs", "mode=0755" TMPFS_LIMITS_RUN, MS_NOSUID|MS_NODEV|MS_STRICTATIME, |
| MOUNT_FATAL|MOUNT_MKDIR }, |
| { "/run/host", "/run/host", NULL, NULL, MS_BIND, |
| MOUNT_FATAL|MOUNT_MKDIR|MOUNT_PREFIX_ROOT }, /* Prepare this so that we can make it read-only when we are done */ |
| { "/etc/os-release", "/run/host/os-release", NULL, NULL, MS_BIND, |
| MOUNT_TOUCH }, /* As per kernel interface requirements, bind mount first (creating mount points) and make read-only later */ |
| { "/usr/lib/os-release", "/run/host/os-release", NULL, NULL, MS_BIND, |
| MOUNT_FATAL }, /* If /etc/os-release doesn't exist use the version in /usr/lib as fallback */ |
| { NULL, "/run/host/os-release", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, |
| MOUNT_FATAL }, |
| { NULL, "/run/host", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, |
| MOUNT_FATAL|MOUNT_IN_USERNS }, |
| #if HAVE_SELINUX |
| { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, |
| MOUNT_MKDIR }, /* Bind mount first (mkdir/chown the mount point in case /sys/ is mounted as minimal skeleton tmpfs) */ |
| { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, |
| 0 }, /* Then, make it r/o (don't mkdir/chown the mount point here, the previous entry already did that) */ |
| #endif |
| }; |
| |
| bool use_userns = FLAGS_SET(mount_settings, MOUNT_USE_USERNS); |
| bool netns = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_NETNS); |
| bool ro = FLAGS_SET(mount_settings, MOUNT_APPLY_APIVFS_RO); |
| bool in_userns = FLAGS_SET(mount_settings, MOUNT_IN_USERNS); |
| bool tmpfs_tmp = FLAGS_SET(mount_settings, MOUNT_APPLY_TMPFS_TMP); |
| int r; |
| |
| for (size_t k = 0; k < ELEMENTSOF(mount_table); k++) { |
| _cleanup_free_ char *where = NULL, *options = NULL, *prefixed = NULL; |
| bool fatal = FLAGS_SET(mount_table[k].mount_settings, MOUNT_FATAL); |
| const char *o; |
| |
| if (in_userns != FLAGS_SET(mount_table[k].mount_settings, MOUNT_IN_USERNS)) |
| continue; |
| |
| if (!netns && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_APIVFS_NETNS)) |
| continue; |
| |
| if (!ro && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_APIVFS_RO)) |
| continue; |
| |
| if (!tmpfs_tmp && FLAGS_SET(mount_table[k].mount_settings, MOUNT_APPLY_TMPFS_TMP)) |
| continue; |
| |
| r = chase_symlinks(mount_table[k].where, dest, CHASE_NONEXISTENT|CHASE_PREFIX_ROOT, &where, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].where); |
| |
| /* Skip this entry if it is not a remount. */ |
| if (mount_table[k].what) { |
| r = path_is_mount_point(where, NULL, 0); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); |
| if (r > 0) |
| continue; |
| } |
| |
| if ((mount_table[k].mount_settings & (MOUNT_MKDIR|MOUNT_TOUCH)) != 0) { |
| uid_t u = (use_userns && !in_userns) ? uid_shift : UID_INVALID; |
| |
| if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_TOUCH)) |
| r = mkdir_parents_safe(dest, where, 0755, u, u, 0); |
| else |
| r = mkdir_p_safe(dest, where, 0755, u, u, 0); |
| if (r < 0 && r != -EEXIST) { |
| if (fatal && r != -EROFS) |
| return log_error_errno(r, "Failed to create directory %s: %m", where); |
| |
| log_debug_errno(r, "Failed to create directory %s: %m", where); |
| |
| /* If we failed mkdir() or chown() due to the root directory being read only, |
| * attempt to mount this fs anyway and let mount_verbose log any errors */ |
| if (r != -EROFS) |
| continue; |
| } |
| } |
| |
| if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_TOUCH)) { |
| r = touch(where); |
| if (r < 0 && r != -EEXIST) { |
| if (fatal && r != -EROFS) |
| return log_error_errno(r, "Failed to create file %s: %m", where); |
| |
| log_debug_errno(r, "Failed to create file %s: %m", where); |
| if (r != -EROFS) |
| continue; |
| } |
| } |
| |
| o = mount_table[k].options; |
| if (streq_ptr(mount_table[k].type, "tmpfs")) { |
| r = tmpfs_patch_options(o, in_userns ? 0 : uid_shift, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| o = options; |
| } |
| |
| if (FLAGS_SET(mount_table[k].mount_settings, MOUNT_PREFIX_ROOT)) { |
| /* Optionally prefix the mount source with the root dir. This is useful in bind |
| * mounts to be created within the container image before we transition into it. Note |
| * that MOUNT_IN_USERNS is run after we transitioned hence prefixing is not ncessary |
| * for those. */ |
| r = chase_symlinks(mount_table[k].what, dest, CHASE_PREFIX_ROOT, &prefixed, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, mount_table[k].what); |
| } |
| |
| r = mount_verbose_full( |
| fatal ? LOG_ERR : LOG_DEBUG, |
| prefixed ?: mount_table[k].what, |
| where, |
| mount_table[k].type, |
| mount_table[k].flags, |
| o, |
| FLAGS_SET(mount_table[k].mount_settings, MOUNT_FOLLOW_SYMLINKS)); |
| if (r < 0 && fatal) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts, RemountIdmapping *idmapping) { |
| unsigned long flags = *mount_flags; |
| char *opts = NULL; |
| RemountIdmapping new_idmapping = *idmapping; |
| int r; |
| |
| assert(options); |
| |
| for (;;) { |
| _cleanup_free_ char *word = NULL; |
| |
| r = extract_first_word(&options, &word, ",", 0); |
| if (r < 0) |
| return log_error_errno(r, "Failed to extract mount option: %m"); |
| if (r == 0) |
| break; |
| |
| if (streq(word, "rbind")) |
| flags |= MS_REC; |
| else if (streq(word, "norbind")) |
| flags &= ~MS_REC; |
| else if (streq(word, "idmap")) |
| new_idmapping = REMOUNT_IDMAPPING_HOST_ROOT; |
| else if (streq(word, "noidmap")) |
| new_idmapping = REMOUNT_IDMAPPING_NONE; |
| else if (streq(word, "rootidmap")) |
| new_idmapping = REMOUNT_IDMAPPING_HOST_OWNER; |
| else |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Invalid bind mount option: %s", word); |
| } |
| |
| *mount_flags = flags; |
| *idmapping = new_idmapping; |
| /* in the future mount_opts will hold string options for mount(2) */ |
| *mount_opts = opts; |
| |
| return 0; |
| } |
| |
| static int mount_bind(const char *dest, CustomMount *m, uid_t uid_shift, uid_t uid_range) { |
| _cleanup_free_ char *mount_opts = NULL, *where = NULL; |
| unsigned long mount_flags = MS_BIND | MS_REC; |
| struct stat source_st, dest_st; |
| int r; |
| RemountIdmapping idmapping = REMOUNT_IDMAPPING_NONE; |
| |
| assert(dest); |
| assert(m); |
| |
| if (m->options) { |
| r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts, &idmapping); |
| if (r < 0) |
| return r; |
| } |
| |
| /* If this is a bind mount from a temporary sources change ownership of the source to the container's |
| * root UID. Otherwise it would always show up as "nobody" if user namespacing is used. */ |
| if (m->rm_rf_tmpdir && chown(m->source, uid_shift, uid_shift) < 0) |
| return log_error_errno(errno, "Failed to chown %s: %m", m->source); |
| |
| if (stat(m->source, &source_st) < 0) |
| return log_error_errno(errno, "Failed to stat %s: %m", m->source); |
| |
| r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
| if (r > 0) { /* Path exists already? */ |
| |
| if (stat(where, &dest_st) < 0) |
| return log_error_errno(errno, "Failed to stat %s: %m", where); |
| |
| if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Cannot bind mount directory %s on file %s.", |
| m->source, where); |
| |
| if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Cannot bind mount file %s on directory %s.", |
| m->source, where); |
| |
| } else { /* Path doesn't exist yet? */ |
| r = mkdir_parents_safe_label(dest, where, 0755, uid_shift, uid_shift, MKDIR_IGNORE_EXISTING); |
| if (r < 0) |
| return log_error_errno(r, "Failed to make parents of %s: %m", where); |
| |
| /* Create the mount point. Any non-directory file can be |
| * mounted on any non-directory file (regular, fifo, socket, |
| * char, block). |
| */ |
| if (S_ISDIR(source_st.st_mode)) |
| r = mkdir_label(where, 0755); |
| else |
| r = touch(where); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create mount point %s: %m", where); |
| |
| if (chown(where, uid_shift, uid_shift) < 0) |
| return log_error_errno(errno, "Failed to chown %s: %m", where); |
| } |
| |
| r = mount_nofollow_verbose(LOG_ERR, m->source, where, NULL, mount_flags, mount_opts); |
| if (r < 0) |
| return r; |
| |
| if (m->read_only) { |
| r = bind_remount_recursive(where, MS_RDONLY, MS_RDONLY, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Read-only bind mount failed: %m"); |
| } |
| |
| if (idmapping != REMOUNT_IDMAPPING_NONE) { |
| r = remount_idmap(where, uid_shift, uid_range, source_st.st_uid, idmapping); |
| if (r < 0) |
| return log_error_errno(r, "Failed to map ids for bind mount %s: %m", where); |
| } |
| |
| return 0; |
| } |
| |
| static int mount_tmpfs(const char *dest, CustomMount *m, uid_t uid_shift, const char *selinux_apifs_context) { |
| const char *options; |
| _cleanup_free_ char *buf = NULL, *where = NULL; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
| if (r == 0) { /* Doesn't exist yet? */ |
| r = mkdir_p_label(where, 0755); |
| if (r < 0) |
| return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); |
| } |
| |
| r = tmpfs_patch_options(m->options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| options = r > 0 ? buf : m->options; |
| |
| return mount_nofollow_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options); |
| } |
| |
| static char *joined_and_escaped_lower_dirs(char **lower) { |
| _cleanup_strv_free_ char **sv = NULL; |
| |
| sv = strv_copy(lower); |
| if (!sv) |
| return NULL; |
| |
| strv_reverse(sv); |
| |
| if (!strv_shell_escape(sv, ",:")) |
| return NULL; |
| |
| return strv_join(sv, ":"); |
| } |
| |
| static int mount_overlay(const char *dest, CustomMount *m) { |
| _cleanup_free_ char *lower = NULL, *where = NULL, *escaped_source = NULL; |
| const char *options; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
| if (r == 0) { /* Doesn't exist yet? */ |
| r = mkdir_label(where, 0755); |
| if (r < 0) |
| return log_error_errno(r, "Creating mount point for overlay %s failed: %m", where); |
| } |
| |
| (void) mkdir_p_label(m->source, 0755); |
| |
| lower = joined_and_escaped_lower_dirs(m->lower); |
| if (!lower) |
| return log_oom(); |
| |
| escaped_source = shell_escape(m->source, ",:"); |
| if (!escaped_source) |
| return log_oom(); |
| |
| if (m->read_only) |
| options = strjoina("lowerdir=", escaped_source, ":", lower); |
| else { |
| _cleanup_free_ char *escaped_work_dir = NULL; |
| |
| escaped_work_dir = shell_escape(m->work_dir, ",:"); |
| if (!escaped_work_dir) |
| return log_oom(); |
| |
| options = strjoina("lowerdir=", lower, ",upperdir=", escaped_source, ",workdir=", escaped_work_dir); |
| } |
| |
| return mount_nofollow_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options); |
| } |
| |
| static int mount_inaccessible(const char *dest, CustomMount *m) { |
| _cleanup_free_ char *where = NULL, *source = NULL; |
| struct stat st; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| r = chase_symlinks_and_stat(m->destination, dest, CHASE_PREFIX_ROOT, &where, &st, NULL); |
| if (r < 0) { |
| log_full_errno(m->graceful ? LOG_DEBUG : LOG_ERR, r, "Failed to resolve %s/%s: %m", dest, m->destination); |
| return m->graceful ? 0 : r; |
| } |
| |
| r = mode_to_inaccessible_node(NULL, st.st_mode, &source); |
| if (r < 0) |
| return m->graceful ? 0 : r; |
| |
| r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, source, where, NULL, MS_BIND, NULL); |
| if (r < 0) |
| return m->graceful ? 0 : r; |
| |
| r = mount_nofollow_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, NULL, where, NULL, MS_BIND|MS_RDONLY|MS_REMOUNT, NULL); |
| if (r < 0) { |
| (void) umount_verbose(m->graceful ? LOG_DEBUG : LOG_ERR, where, UMOUNT_NOFOLLOW); |
| return m->graceful ? 0 : r; |
| } |
| |
| return 0; |
| } |
| |
| static int mount_arbitrary(const char *dest, CustomMount *m) { |
| _cleanup_free_ char *where = NULL; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| r = chase_symlinks(m->destination, dest, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &where, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to resolve %s/%s: %m", dest, m->destination); |
| if (r == 0) { /* Doesn't exist yet? */ |
| r = mkdir_p_label(where, 0755); |
| if (r < 0) |
| return log_error_errno(r, "Creating mount point for mount %s failed: %m", where); |
| } |
| |
| return mount_nofollow_verbose(LOG_ERR, m->source, where, m->type_argument, 0, m->options); |
| } |
| |
| int mount_custom( |
| const char *dest, |
| CustomMount *mounts, size_t n, |
| uid_t uid_shift, |
| uid_t uid_range, |
| const char *selinux_apifs_context, |
| MountSettingsMask mount_settings) { |
| int r; |
| |
| assert(dest); |
| |
| for (size_t i = 0; i < n; i++) { |
| CustomMount *m = mounts + i; |
| |
| if (FLAGS_SET(mount_settings, MOUNT_IN_USERNS) != m->in_userns) |
| continue; |
| |
| if (FLAGS_SET(mount_settings, MOUNT_ROOT_ONLY) && !path_equal(m->destination, "/")) |
| continue; |
| |
| if (FLAGS_SET(mount_settings, MOUNT_NON_ROOT_ONLY) && path_equal(m->destination, "/")) |
| continue; |
| |
| switch (m->type) { |
| |
| case CUSTOM_MOUNT_BIND: |
| r = mount_bind(dest, m, uid_shift, uid_range); |
| break; |
| |
| case CUSTOM_MOUNT_TMPFS: |
| r = mount_tmpfs(dest, m, uid_shift, selinux_apifs_context); |
| break; |
| |
| case CUSTOM_MOUNT_OVERLAY: |
| r = mount_overlay(dest, m); |
| break; |
| |
| case CUSTOM_MOUNT_INACCESSIBLE: |
| r = mount_inaccessible(dest, m); |
| break; |
| |
| case CUSTOM_MOUNT_ARBITRARY: |
| r = mount_arbitrary(dest, m); |
| break; |
| |
| default: |
| assert_not_reached(); |
| } |
| |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| bool has_custom_root_mount(const CustomMount *mounts, size_t n) { |
| for (size_t i = 0; i < n; i++) |
| if (path_equal(mounts[i].destination, "/")) |
| return true; |
| |
| return false; |
| } |
| |
| static int setup_volatile_state(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
| _cleanup_free_ char *buf = NULL; |
| const char *p, *options; |
| int r; |
| |
| assert(directory); |
| |
| /* --volatile=state means we simply overmount /var with a tmpfs, and the rest read-only. */ |
| |
| r = bind_remount_recursive(directory, MS_RDONLY, MS_RDONLY, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to remount %s read-only: %m", directory); |
| |
| p = prefix_roota(directory, "/var"); |
| r = mkdir(p, 0755); |
| if (r < 0 && errno != EEXIST) |
| return log_error_errno(errno, "Failed to create %s: %m", directory); |
| |
| options = "mode=0755" TMPFS_LIMITS_VOLATILE_STATE; |
| r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| options = buf; |
| |
| return mount_nofollow_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options); |
| } |
| |
| static int setup_volatile_yes(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
| bool tmpfs_mounted = false, bind_mounted = false; |
| char template[] = "/tmp/nspawn-volatile-XXXXXX"; |
| _cleanup_free_ char *buf = NULL, *bindir = NULL; |
| const char *f, *t, *options; |
| struct stat st; |
| int r; |
| |
| assert(directory); |
| |
| /* --volatile=yes means we mount a tmpfs to the root dir, and the original /usr to use inside it, and |
| * that read-only. Before we start setting this up let's validate if the image has the /usr merge |
| * implemented, and let's output a friendly log message if it hasn't. */ |
| |
| bindir = path_join(directory, "/bin"); |
| if (!bindir) |
| return log_oom(); |
| if (lstat(bindir, &st) < 0) { |
| if (errno != ENOENT) |
| return log_error_errno(errno, "Failed to stat /bin directory below image: %m"); |
| |
| /* ENOENT is fine, just means the image is probably just a naked /usr and we can create the |
| * rest. */ |
| } else if (S_ISDIR(st.st_mode)) |
| return log_error_errno(SYNTHETIC_ERRNO(EISDIR), |
| "Sorry, --volatile=yes mode is not supported with OS images that have not merged /bin/, /sbin/, /lib/, /lib64/ into /usr/. " |
| "Please work with your distribution and help them adopt the merged /usr scheme."); |
| else if (!S_ISLNK(st.st_mode)) |
| return log_error_errno(SYNTHETIC_ERRNO(EINVAL), |
| "Error starting image: if --volatile=yes is used /bin must be a symlink (for merged /usr support) or non-existent (in which case a symlink is created automatically)."); |
| |
| if (!mkdtemp(template)) |
| return log_error_errno(errno, "Failed to create temporary directory: %m"); |
| |
| options = "mode=0755" TMPFS_LIMITS_ROOTFS; |
| r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
| if (r < 0) |
| goto fail; |
| if (r > 0) |
| options = buf; |
| |
| r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); |
| if (r < 0) |
| goto fail; |
| |
| tmpfs_mounted = true; |
| |
| f = prefix_roota(directory, "/usr"); |
| t = prefix_roota(template, "/usr"); |
| |
| r = mkdir(t, 0755); |
| if (r < 0 && errno != EEXIST) { |
| r = log_error_errno(errno, "Failed to create %s: %m", t); |
| goto fail; |
| } |
| |
| r = mount_nofollow_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL); |
| if (r < 0) |
| goto fail; |
| |
| bind_mounted = true; |
| |
| r = bind_remount_recursive(t, MS_RDONLY, MS_RDONLY, NULL); |
| if (r < 0) { |
| log_error_errno(r, "Failed to remount %s read-only: %m", t); |
| goto fail; |
| } |
| |
| r = mount_nofollow_verbose(LOG_ERR, template, directory, NULL, MS_MOVE, NULL); |
| if (r < 0) |
| goto fail; |
| |
| (void) rmdir(template); |
| |
| return 0; |
| |
| fail: |
| if (bind_mounted) |
| (void) umount_verbose(LOG_ERR, t, UMOUNT_NOFOLLOW); |
| |
| if (tmpfs_mounted) |
| (void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW); |
| |
| (void) rmdir(template); |
| return r; |
| } |
| |
| static int setup_volatile_overlay(const char *directory, uid_t uid_shift, const char *selinux_apifs_context) { |
| _cleanup_free_ char *buf = NULL, *escaped_directory = NULL, *escaped_upper = NULL, *escaped_work = NULL; |
| char template[] = "/tmp/nspawn-volatile-XXXXXX"; |
| const char *upper, *work, *options; |
| bool tmpfs_mounted = false; |
| int r; |
| |
| assert(directory); |
| |
| /* --volatile=overlay means we mount an overlayfs to the root dir. */ |
| |
| if (!mkdtemp(template)) |
| return log_error_errno(errno, "Failed to create temporary directory: %m"); |
| |
| options = "mode=0755" TMPFS_LIMITS_ROOTFS; |
| r = tmpfs_patch_options(options, uid_shift == 0 ? UID_INVALID : uid_shift, selinux_apifs_context, &buf); |
| if (r < 0) |
| goto finish; |
| if (r > 0) |
| options = buf; |
| |
| r = mount_nofollow_verbose(LOG_ERR, "tmpfs", template, "tmpfs", MS_STRICTATIME, options); |
| if (r < 0) |
| goto finish; |
| |
| tmpfs_mounted = true; |
| |
| upper = strjoina(template, "/upper"); |
| work = strjoina(template, "/work"); |
| |
| if (mkdir(upper, 0755) < 0) { |
| r = log_error_errno(errno, "Failed to create %s: %m", upper); |
| goto finish; |
| } |
| if (mkdir(work, 0755) < 0) { |
| r = log_error_errno(errno, "Failed to create %s: %m", work); |
| goto finish; |
| } |
| |
| /* And now, let's overmount the root dir with an overlayfs that uses the root dir as lower dir. It's kinda nice |
| * that the kernel allows us to do that without going through some mount point rearrangements. */ |
| |
| escaped_directory = shell_escape(directory, ",:"); |
| escaped_upper = shell_escape(upper, ",:"); |
| escaped_work = shell_escape(work, ",:"); |
| if (!escaped_directory || !escaped_upper || !escaped_work) { |
| r = -ENOMEM; |
| goto finish; |
| } |
| |
| options = strjoina("lowerdir=", escaped_directory, ",upperdir=", escaped_upper, ",workdir=", escaped_work); |
| r = mount_nofollow_verbose(LOG_ERR, "overlay", directory, "overlay", 0, options); |
| |
| finish: |
| if (tmpfs_mounted) |
| (void) umount_verbose(LOG_ERR, template, UMOUNT_NOFOLLOW); |
| |
| (void) rmdir(template); |
| return r; |
| } |
| |
| int setup_volatile_mode( |
| const char *directory, |
| VolatileMode mode, |
| uid_t uid_shift, |
| const char *selinux_apifs_context) { |
| |
| switch (mode) { |
| |
| case VOLATILE_YES: |
| return setup_volatile_yes(directory, uid_shift, selinux_apifs_context); |
| |
| case VOLATILE_STATE: |
| return setup_volatile_state(directory, uid_shift, selinux_apifs_context); |
| |
| case VOLATILE_OVERLAY: |
| return setup_volatile_overlay(directory, uid_shift, selinux_apifs_context); |
| |
| default: |
| return 0; |
| } |
| } |
| |
| /* Expects *pivot_root_new and *pivot_root_old to be initialised to allocated memory or NULL. */ |
| int pivot_root_parse(char **pivot_root_new, char **pivot_root_old, const char *s) { |
| _cleanup_free_ char *root_new = NULL, *root_old = NULL; |
| const char *p = s; |
| int r; |
| |
| assert(pivot_root_new); |
| assert(pivot_root_old); |
| |
| r = extract_first_word(&p, &root_new, ":", EXTRACT_DONT_COALESCE_SEPARATORS); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| |
| if (isempty(p)) |
| root_old = NULL; |
| else { |
| root_old = strdup(p); |
| if (!root_old) |
| return -ENOMEM; |
| } |
| |
| if (!path_is_absolute(root_new)) |
| return -EINVAL; |
| if (root_old && !path_is_absolute(root_old)) |
| return -EINVAL; |
| |
| free_and_replace(*pivot_root_new, root_new); |
| free_and_replace(*pivot_root_old, root_old); |
| |
| return 0; |
| } |
| |
| int setup_pivot_root(const char *directory, const char *pivot_root_new, const char *pivot_root_old) { |
| _cleanup_free_ char *directory_pivot_root_new = NULL; |
| _cleanup_free_ char *pivot_tmp_pivot_root_old = NULL; |
| char pivot_tmp[] = "/tmp/nspawn-pivot-XXXXXX"; |
| bool remove_pivot_tmp = false; |
| int r; |
| |
| assert(directory); |
| |
| if (!pivot_root_new) |
| return 0; |
| |
| /* Pivot pivot_root_new to / and the existing / to pivot_root_old. |
| * If pivot_root_old is NULL, the existing / disappears. |
| * This requires a temporary directory, pivot_tmp, which is |
| * not a child of either. |
| * |
| * This is typically used for OSTree-style containers, where the root partition contains several |
| * sysroots which could be run. Normally, one would be chosen by the bootloader and pivoted to / by |
| * initrd. |
| * |
| * For example, for an OSTree deployment, pivot_root_new |
| * would be: /ostree/deploy/$os/deploy/$checksum. Note that this |
| * code doesn’t do the /var mount which OSTree expects: use |
| * --bind +/sysroot/ostree/deploy/$os/var:/var for that. |
| * |
| * So in the OSTree case, we’ll end up with something like: |
| * - directory = /tmp/nspawn-root-123456 |
| * - pivot_root_new = /ostree/deploy/os/deploy/123abc |
| * - pivot_root_old = /sysroot |
| * - directory_pivot_root_new = |
| * /tmp/nspawn-root-123456/ostree/deploy/os/deploy/123abc |
| * - pivot_tmp = /tmp/nspawn-pivot-123456 |
| * - pivot_tmp_pivot_root_old = /tmp/nspawn-pivot-123456/sysroot |
| * |
| * Requires all file systems at directory and below to be mounted |
| * MS_PRIVATE or MS_SLAVE so they can be moved. |
| */ |
| directory_pivot_root_new = path_join(directory, pivot_root_new); |
| if (!directory_pivot_root_new) |
| return log_oom(); |
| |
| /* Remount directory_pivot_root_new to make it movable. */ |
| r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory_pivot_root_new, NULL, MS_BIND, NULL); |
| if (r < 0) |
| goto done; |
| |
| if (pivot_root_old) { |
| if (!mkdtemp(pivot_tmp)) { |
| r = log_error_errno(errno, "Failed to create temporary directory: %m"); |
| goto done; |
| } |
| |
| remove_pivot_tmp = true; |
| pivot_tmp_pivot_root_old = path_join(pivot_tmp, pivot_root_old); |
| if (!pivot_tmp_pivot_root_old) { |
| r = log_oom(); |
| goto done; |
| } |
| |
| r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, pivot_tmp, NULL, MS_MOVE, NULL); |
| if (r < 0) |
| goto done; |
| |
| r = mount_nofollow_verbose(LOG_ERR, directory, pivot_tmp_pivot_root_old, NULL, MS_MOVE, NULL); |
| if (r < 0) |
| goto done; |
| |
| r = mount_nofollow_verbose(LOG_ERR, pivot_tmp, directory, NULL, MS_MOVE, NULL); |
| if (r < 0) |
| goto done; |
| } else { |
| r = mount_nofollow_verbose(LOG_ERR, directory_pivot_root_new, directory, NULL, MS_MOVE, NULL); |
| if (r < 0) |
| goto done; |
| } |
| |
| done: |
| if (remove_pivot_tmp) |
| (void) rmdir(pivot_tmp); |
| |
| return r; |
| } |
| |
| #define NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS "/run/host/proc" |
| #define NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS "/run/host/sys" |
| |
| int pin_fully_visible_fs(void) { |
| int r; |
| |
| (void) mkdir_p(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, 0755); |
| (void) mkdir_p(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, 0755); |
| |
| r = mount_follow_verbose(LOG_ERR, "proc", NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, "proc", PROC_DEFAULT_MOUNT_FLAGS, NULL); |
| if (r < 0) |
| return r; |
| |
| r = mount_follow_verbose(LOG_ERR, "sysfs", NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, "sysfs", SYS_DEFAULT_MOUNT_FLAGS, NULL); |
| if (r < 0) |
| return r; |
| |
| return 0; |
| } |
| |
| static int do_wipe_fully_visible_fs(void) { |
| if (umount2(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS, MNT_DETACH) < 0) |
| return log_error_errno(errno, "Failed to unmount temporary proc: %m"); |
| |
| if (rmdir(NSPAWN_PRIVATE_FULLY_VISIBLE_PROCFS) < 0) |
| return log_error_errno(errno, "Failed to remove temporary proc mountpoint: %m"); |
| |
| if (umount2(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS, MNT_DETACH) < 0) |
| return log_error_errno(errno, "Failed to unmount temporary sys: %m"); |
| |
| if (rmdir(NSPAWN_PRIVATE_FULLY_VISIBLE_SYSFS) < 0) |
| return log_error_errno(errno, "Failed to remove temporary sys mountpoint: %m"); |
| |
| return 0; |
| } |
| |
| int wipe_fully_visible_fs(int mntns_fd) { |
| _cleanup_close_ int orig_mntns_fd = -EBADF; |
| int r, rr; |
| |
| r = namespace_open(0, NULL, &orig_mntns_fd, NULL, NULL, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Failed to pin originating mount namespace: %m"); |
| |
| r = namespace_enter(-EBADF, mntns_fd, -EBADF, -EBADF, -EBADF); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enter mount namespace: %m"); |
| |
| rr = do_wipe_fully_visible_fs(); |
| |
| r = namespace_enter(-EBADF, orig_mntns_fd, -EBADF, -EBADF, -EBADF); |
| if (r < 0) |
| return log_error_errno(r, "Failed to enter original mount namespace: %m"); |
| |
| return rr; |
| } |
