| /*** |
| This file is part of systemd. |
| |
| Copyright 2015 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 <sys/mount.h> |
| #include <linux/magic.h> |
| |
| #include "alloc-util.h" |
| #include "escape.h" |
| #include "fd-util.h" |
| #include "fileio.h" |
| #include "fs-util.h" |
| #include "label.h" |
| #include "mkdir.h" |
| #include "mount-util.h" |
| #include "nspawn-mount.h" |
| #include "parse-util.h" |
| #include "path-util.h" |
| #include "rm-rf.h" |
| #include "set.h" |
| #include "stat-util.h" |
| #include "string-util.h" |
| #include "strv.h" |
| #include "user-util.h" |
| #include "util.h" |
| |
| CustomMount* custom_mount_add(CustomMount **l, unsigned *n, CustomMountType t) { |
| CustomMount *c, *ret; |
| |
| assert(l); |
| assert(n); |
| assert(t >= 0); |
| assert(t < _CUSTOM_MOUNT_TYPE_MAX); |
| |
| c = realloc(*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, unsigned n) { |
| unsigned i; |
| |
| for (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); |
| } |
| |
| strv_free(m->lower); |
| } |
| |
| free(l); |
| } |
| |
| int custom_mount_compare(const void *a, const void *b) { |
| const CustomMount *x = a, *y = b; |
| int r; |
| |
| r = path_compare(x->destination, y->destination); |
| if (r != 0) |
| return r; |
| |
| if (x->type < y->type) |
| return -1; |
| if (x->type > y->type) |
| return 1; |
| |
| return 0; |
| } |
| |
| int bind_mount_parse(CustomMount **l, unsigned *n, const char *s, bool read_only) { |
| _cleanup_free_ char *source = NULL, *destination = NULL, *opts = NULL; |
| const char *p = s; |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| |
| r = extract_many_words(&p, ":", EXTRACT_DONT_COALESCE_SEPARATORS, &source, &destination, NULL); |
| if (r < 0) |
| return r; |
| if (r == 0) |
| return -EINVAL; |
| |
| if (r == 1) { |
| destination = strdup(source); |
| if (!destination) |
| return -ENOMEM; |
| } |
| |
| if (r == 2 && !isempty(p)) { |
| opts = strdup(p); |
| if (!opts) |
| return -ENOMEM; |
| } |
| |
| if (!path_is_absolute(source)) |
| return -EINVAL; |
| |
| if (!path_is_absolute(destination)) |
| return -EINVAL; |
| |
| m = custom_mount_add(l, n, CUSTOM_MOUNT_BIND); |
| if (!m) |
| return log_oom(); |
| |
| m->source = source; |
| m->destination = destination; |
| m->read_only = read_only; |
| m->options = opts; |
| |
| source = destination = opts = NULL; |
| return 0; |
| } |
| |
| int tmpfs_mount_parse(CustomMount **l, unsigned *n, const char *s) { |
| _cleanup_free_ char *path = NULL, *opts = NULL; |
| const char *p = s; |
| CustomMount *m; |
| int r; |
| |
| assert(l); |
| assert(n); |
| assert(s); |
| |
| 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 = path; |
| m->options = opts; |
| |
| path = opts = NULL; |
| return 0; |
| } |
| |
| static int tmpfs_patch_options( |
| const char *options, |
| bool userns, |
| uid_t uid_shift, uid_t uid_range, |
| bool patch_ids, |
| const char *selinux_apifs_context, |
| char **ret) { |
| |
| char *buf = NULL; |
| |
| if ((userns && uid_shift != 0) || patch_ids) { |
| assert(uid_shift != UID_INVALID); |
| |
| if (options) |
| (void) asprintf(&buf, "%s,uid=" UID_FMT ",gid=" UID_FMT, options, uid_shift, uid_shift); |
| else |
| (void) asprintf(&buf, "uid=" UID_FMT ",gid=" UID_FMT, uid_shift, uid_shift); |
| if (!buf) |
| return -ENOMEM; |
| |
| options = buf; |
| } |
| |
| #ifdef HAVE_SELINUX |
| if (selinux_apifs_context) { |
| char *t; |
| |
| if (options) |
| t = strjoin(options, ",context=\"", selinux_apifs_context, "\"", NULL); |
| else |
| t = strjoin("context=\"", selinux_apifs_context, "\"", NULL); |
| if (!t) { |
| free(buf); |
| return -ENOMEM; |
| } |
| |
| free(buf); |
| buf = t; |
| } |
| #endif |
| |
| if (!buf && options) { |
| buf = strdup(options); |
| if (!buf) |
| return -ENOMEM; |
| } |
| *ret = buf; |
| |
| return !!buf; |
| } |
| |
| int mount_sysfs(const char *dest) { |
| const char *full, *top, *x; |
| int r; |
| |
| top = prefix_roota(dest, "/sys"); |
| r = path_check_fstype(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); |
| |
| r = mount_verbose(LOG_ERR, "sysfs", full, "sysfs", |
| MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL); |
| if (r < 0) |
| return r; |
| |
| FOREACH_STRING(x, "block", "bus", "class", "dev", "devices", "kernel") { |
| _cleanup_free_ char *from = NULL, *to = NULL; |
| |
| from = prefix_root(full, x); |
| if (!from) |
| return log_oom(); |
| |
| to = prefix_root(top, x); |
| if (!to) |
| return log_oom(); |
| |
| (void) mkdir(to, 0755); |
| |
| r = mount_verbose(LOG_ERR, from, to, NULL, MS_BIND, NULL); |
| if (r < 0) |
| return r; |
| |
| r = mount_verbose(LOG_ERR, NULL, to, NULL, |
| MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| r = umount_verbose(full); |
| if (r < 0) |
| return r; |
| |
| if (rmdir(full) < 0) |
| return log_error_errno(errno, "Failed to remove %s: %m", full); |
| |
| x = prefix_roota(top, "/fs/kdbus"); |
| (void) mkdir_p(x, 0755); |
| |
| /* Create mountpoint for cgroups. Otherwise we are not allowed since we |
| * remount /sys read-only. |
| */ |
| if (cg_ns_supported()) { |
| x = prefix_roota(top, "/fs/cgroup"); |
| (void) mkdir_p(x, 0755); |
| } |
| |
| return mount_verbose(LOG_ERR, NULL, top, NULL, |
| MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, NULL); |
| } |
| |
| static int mkdir_userns(const char *path, mode_t mode, bool in_userns, uid_t uid_shift) { |
| int r; |
| |
| assert(path); |
| |
| r = mkdir(path, mode); |
| if (r < 0 && errno != EEXIST) |
| return -errno; |
| |
| if (!in_userns) { |
| r = lchown(path, uid_shift, uid_shift); |
| if (r < 0) |
| return -errno; |
| } |
| |
| return 0; |
| } |
| |
| static int mkdir_userns_p(const char *prefix, const char *path, mode_t mode, bool in_userns, uid_t uid_shift) { |
| const char *p, *e; |
| int r; |
| |
| assert(path); |
| |
| if (prefix && !path_startswith(path, prefix)) |
| return -ENOTDIR; |
| |
| /* create every parent directory in the path, except the last component */ |
| p = path + strspn(path, "/"); |
| for (;;) { |
| char t[strlen(path) + 1]; |
| |
| e = p + strcspn(p, "/"); |
| p = e + strspn(e, "/"); |
| |
| /* Is this the last component? If so, then we're done */ |
| if (*p == 0) |
| break; |
| |
| memcpy(t, path, e - path); |
| t[e-path] = 0; |
| |
| if (prefix && path_startswith(prefix, t)) |
| continue; |
| |
| r = mkdir_userns(t, mode, in_userns, uid_shift); |
| if (r < 0) |
| return r; |
| } |
| |
| return mkdir_userns(path, mode, in_userns, uid_shift); |
| } |
| |
| int mount_all(const char *dest, |
| bool use_userns, bool in_userns, |
| bool use_netns, |
| uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| typedef struct MountPoint { |
| const char *what; |
| const char *where; |
| const char *type; |
| const char *options; |
| unsigned long flags; |
| bool fatal; |
| bool in_userns; |
| bool use_netns; |
| } MountPoint; |
| |
| static const MountPoint mount_table[] = { |
| { "proc", "/proc", "proc", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, true, true, false }, |
| { "/proc/sys", "/proc/sys", NULL, NULL, MS_BIND, true, true, false }, /* Bind mount first ...*/ |
| { "/proc/sys/net", "/proc/sys/net", NULL, NULL, MS_BIND, true, true, true }, /* (except for this) */ |
| { NULL, "/proc/sys", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, true, true, false }, /* ... then, make it r/o */ |
| { "/proc/sysrq-trigger", "/proc/sysrq-trigger", NULL, NULL, MS_BIND, false, true, false }, /* Bind mount first ...*/ |
| { NULL, "/proc/sysrq-trigger", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, true, false }, /* ... then, make it r/o */ |
| { "tmpfs", "/sys", "tmpfs", "mode=755", MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, true }, |
| { "sysfs", "/sys", "sysfs", NULL, MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV, true, false, false }, |
| { "tmpfs", "/dev", "tmpfs", "mode=755", MS_NOSUID|MS_STRICTATIME, true, false, false }, |
| { "tmpfs", "/dev/shm", "tmpfs", "mode=1777", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, |
| { "tmpfs", "/run", "tmpfs", "mode=755", MS_NOSUID|MS_NODEV|MS_STRICTATIME, true, false, false }, |
| { "tmpfs", "/tmp", "tmpfs", "mode=1777", MS_STRICTATIME, true, true, false }, |
| #ifdef HAVE_SELINUX |
| { "/sys/fs/selinux", "/sys/fs/selinux", NULL, NULL, MS_BIND, false, false, false }, /* Bind mount first */ |
| { NULL, "/sys/fs/selinux", NULL, NULL, MS_BIND|MS_RDONLY|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_REMOUNT, false, false, false }, /* Then, make it r/o */ |
| #endif |
| }; |
| |
| unsigned k; |
| int r; |
| |
| for (k = 0; k < ELEMENTSOF(mount_table); k++) { |
| _cleanup_free_ char *where = NULL, *options = NULL; |
| const char *o; |
| |
| if (in_userns != mount_table[k].in_userns) |
| continue; |
| |
| if (!use_netns && mount_table[k].use_netns) |
| continue; |
| |
| where = prefix_root(dest, mount_table[k].where); |
| if (!where) |
| return log_oom(); |
| |
| r = path_is_mount_point(where, AT_SYMLINK_FOLLOW); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to detect whether %s is a mount point: %m", where); |
| |
| /* Skip this entry if it is not a remount. */ |
| if (mount_table[k].what && r > 0) |
| continue; |
| |
| r = mkdir_userns_p(dest, where, 0755, in_userns, uid_shift); |
| if (r < 0 && r != -EEXIST) { |
| if (mount_table[k].fatal) |
| return log_error_errno(r, "Failed to create directory %s: %m", where); |
| |
| log_debug_errno(r, "Failed to create directory %s: %m", where); |
| continue; |
| } |
| |
| o = mount_table[k].options; |
| if (streq_ptr(mount_table[k].type, "tmpfs")) { |
| if (in_userns) |
| r = tmpfs_patch_options(o, use_userns, 0, uid_range, true, selinux_apifs_context, &options); |
| else |
| r = tmpfs_patch_options(o, use_userns, uid_shift, uid_range, false, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| o = options; |
| } |
| |
| r = mount_verbose(mount_table[k].fatal ? LOG_ERR : LOG_WARNING, |
| mount_table[k].what, |
| where, |
| mount_table[k].type, |
| mount_table[k].flags, |
| o); |
| if (r < 0 && mount_table[k].fatal) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int parse_mount_bind_options(const char *options, unsigned long *mount_flags, char **mount_opts) { |
| const char *p = options; |
| unsigned long flags = *mount_flags; |
| char *opts = NULL; |
| |
| assert(options); |
| |
| for (;;) { |
| _cleanup_free_ char *word = NULL; |
| int r = extract_first_word(&p, &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 { |
| log_error("Invalid bind mount option: %s", word); |
| return -EINVAL; |
| } |
| } |
| |
| *mount_flags = flags; |
| /* 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) { |
| struct stat source_st, dest_st; |
| const char *where; |
| unsigned long mount_flags = MS_BIND | MS_REC; |
| _cleanup_free_ char *mount_opts = NULL; |
| int r; |
| |
| assert(m); |
| |
| if (m->options) { |
| r = parse_mount_bind_options(m->options, &mount_flags, &mount_opts); |
| if (r < 0) |
| return r; |
| } |
| |
| if (stat(m->source, &source_st) < 0) |
| return log_error_errno(errno, "Failed to stat %s: %m", m->source); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| if (stat(where, &dest_st) >= 0) { |
| if (S_ISDIR(source_st.st_mode) && !S_ISDIR(dest_st.st_mode)) { |
| log_error("Cannot bind mount directory %s on file %s.", m->source, where); |
| return -EINVAL; |
| } |
| |
| if (!S_ISDIR(source_st.st_mode) && S_ISDIR(dest_st.st_mode)) { |
| log_error("Cannot bind mount file %s on directory %s.", m->source, where); |
| return -EINVAL; |
| } |
| |
| } else if (errno == ENOENT) { |
| r = mkdir_parents_label(where, 0755); |
| 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); |
| |
| } else |
| return log_error_errno(errno, "Failed to stat %s: %m", where); |
| |
| r = mount_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, true, NULL); |
| if (r < 0) |
| return log_error_errno(r, "Read-only bind mount failed: %m"); |
| } |
| |
| return 0; |
| } |
| |
| static int mount_tmpfs( |
| const char *dest, |
| CustomMount *m, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| const char *where, *options; |
| _cleanup_free_ char *buf = NULL; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| r = mkdir_p_label(where, 0755); |
| if (r < 0 && r != -EEXIST) |
| return log_error_errno(r, "Creating mount point for tmpfs %s failed: %m", where); |
| |
| r = tmpfs_patch_options(m->options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| options = r > 0 ? buf : m->options; |
| |
| return mount_verbose(LOG_ERR, "tmpfs", where, "tmpfs", MS_NODEV|MS_STRICTATIME, options); |
| } |
| |
| static char *joined_and_escaped_lower_dirs(char * const *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; |
| const char *where, *options; |
| int r; |
| |
| assert(dest); |
| assert(m); |
| |
| where = prefix_roota(dest, m->destination); |
| |
| r = mkdir_label(where, 0755); |
| if (r < 0 && r != -EEXIST) |
| 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(); |
| |
| if (m->read_only) { |
| _cleanup_free_ char *escaped_source = NULL; |
| |
| escaped_source = shell_escape(m->source, ",:"); |
| if (!escaped_source) |
| return log_oom(); |
| |
| options = strjoina("lowerdir=", escaped_source, ":", lower); |
| } else { |
| _cleanup_free_ char *escaped_source = NULL, *escaped_work_dir = NULL; |
| |
| assert(m->work_dir); |
| (void) mkdir_label(m->work_dir, 0700); |
| |
| escaped_source = shell_escape(m->source, ",:"); |
| if (!escaped_source) |
| return log_oom(); |
| 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_verbose(LOG_ERR, "overlay", where, "overlay", m->read_only ? MS_RDONLY : 0, options); |
| } |
| |
| int mount_custom( |
| const char *dest, |
| CustomMount *mounts, unsigned n, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| unsigned i; |
| int r; |
| |
| assert(dest); |
| |
| for (i = 0; i < n; i++) { |
| CustomMount *m = mounts + i; |
| |
| switch (m->type) { |
| |
| case CUSTOM_MOUNT_BIND: |
| r = mount_bind(dest, m); |
| break; |
| |
| case CUSTOM_MOUNT_TMPFS: |
| r = mount_tmpfs(dest, m, userns, uid_shift, uid_range, selinux_apifs_context); |
| break; |
| |
| case CUSTOM_MOUNT_OVERLAY: |
| r = mount_overlay(dest, m); |
| break; |
| |
| default: |
| assert_not_reached("Unknown custom mount type"); |
| } |
| |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| /* Retrieve existing subsystems. This function is called in a new cgroup |
| * namespace. |
| */ |
| static int get_controllers(Set *subsystems) { |
| _cleanup_fclose_ FILE *f = NULL; |
| char line[LINE_MAX]; |
| |
| assert(subsystems); |
| |
| f = fopen("/proc/self/cgroup", "re"); |
| if (!f) |
| return errno == ENOENT ? -ESRCH : -errno; |
| |
| FOREACH_LINE(line, f, return -errno) { |
| int r; |
| char *e, *l, *p; |
| |
| l = strchr(line, ':'); |
| if (!l) |
| continue; |
| |
| l++; |
| e = strchr(l, ':'); |
| if (!e) |
| continue; |
| |
| *e = 0; |
| |
| if (STR_IN_SET(l, "", "name=systemd")) |
| continue; |
| |
| p = strdup(l); |
| if (!p) |
| return -ENOMEM; |
| |
| r = set_consume(subsystems, p); |
| if (r < 0) |
| return r; |
| } |
| |
| return 0; |
| } |
| |
| static int mount_legacy_cgroup_hierarchy(const char *dest, const char *controller, const char *hierarchy, |
| CGroupUnified unified_requested, bool read_only) { |
| const char *to, *fstype, *opts; |
| int r; |
| |
| to = strjoina(strempty(dest), "/sys/fs/cgroup/", hierarchy); |
| |
| r = path_is_mount_point(to, 0); |
| if (r < 0 && r != -ENOENT) |
| return log_error_errno(r, "Failed to determine if %s is mounted already: %m", to); |
| if (r > 0) |
| return 0; |
| |
| mkdir_p(to, 0755); |
| |
| /* The superblock mount options of the mount point need to be |
| * identical to the hosts', and hence writable... */ |
| if (streq(controller, SYSTEMD_CGROUP_CONTROLLER)) { |
| if (unified_requested >= CGROUP_UNIFIED_SYSTEMD) { |
| fstype = "cgroup2"; |
| opts = NULL; |
| } else { |
| fstype = "cgroup"; |
| opts = "none,name=systemd,xattr"; |
| } |
| } else { |
| fstype = "cgroup"; |
| opts = controller; |
| } |
| |
| r = mount_verbose(LOG_ERR, "cgroup", to, fstype, MS_NOSUID|MS_NOEXEC|MS_NODEV, opts); |
| if (r < 0) |
| return r; |
| |
| /* ... hence let's only make the bind mount read-only, not the superblock. */ |
| if (read_only) { |
| r = mount_verbose(LOG_ERR, NULL, to, NULL, |
| MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL); |
| if (r < 0) |
| return r; |
| } |
| |
| return 1; |
| } |
| |
| /* Mount a legacy cgroup hierarchy when cgroup namespaces are supported. */ |
| static int mount_legacy_cgns_supported( |
| CGroupUnified unified_requested, bool userns, uid_t uid_shift, |
| uid_t uid_range, const char *selinux_apifs_context) { |
| _cleanup_set_free_free_ Set *controllers = NULL; |
| const char *cgroup_root = "/sys/fs/cgroup", *c; |
| int r; |
| |
| (void) mkdir_p(cgroup_root, 0755); |
| |
| /* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */ |
| r = path_is_mount_point(cgroup_root, AT_SYMLINK_FOLLOW); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m"); |
| if (r == 0) { |
| _cleanup_free_ char *options = NULL; |
| |
| /* When cgroup namespaces are enabled and user namespaces are |
| * used then the mount of the cgroupfs is done *inside* the new |
| * user namespace. We're root in the new user namespace and the |
| * kernel will happily translate our uid/gid to the correct |
| * uid/gid as seen from e.g. /proc/1/mountinfo. So we simply |
| * pass uid 0 and not uid_shift to tmpfs_patch_options(). |
| */ |
| r = tmpfs_patch_options("mode=755", userns, 0, uid_range, true, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| |
| r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs", |
| MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options); |
| if (r < 0) |
| return r; |
| } |
| |
| if (cg_all_unified() > 0) |
| goto skip_controllers; |
| |
| controllers = set_new(&string_hash_ops); |
| if (!controllers) |
| return log_oom(); |
| |
| r = get_controllers(controllers); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine cgroup controllers: %m"); |
| |
| for (;;) { |
| _cleanup_free_ const char *controller = NULL; |
| |
| controller = set_steal_first(controllers); |
| if (!controller) |
| break; |
| |
| r = mount_legacy_cgroup_hierarchy("", controller, controller, unified_requested, !userns); |
| if (r < 0) |
| return r; |
| |
| /* When multiple hierarchies are co-mounted, make their |
| * constituting individual hierarchies a symlink to the |
| * co-mount. |
| */ |
| c = controller; |
| for (;;) { |
| _cleanup_free_ char *target = NULL, *tok = NULL; |
| |
| r = extract_first_word(&c, &tok, ",", 0); |
| if (r < 0) |
| return log_error_errno(r, "Failed to extract co-mounted cgroup controller: %m"); |
| if (r == 0) |
| break; |
| |
| target = prefix_root("/sys/fs/cgroup", tok); |
| if (!target) |
| return log_oom(); |
| |
| if (streq(controller, tok)) |
| break; |
| |
| r = symlink_idempotent(controller, target); |
| if (r == -EINVAL) |
| return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m"); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); |
| } |
| } |
| |
| skip_controllers: |
| r = mount_legacy_cgroup_hierarchy("", SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false); |
| if (r < 0) |
| return r; |
| |
| if (!userns) |
| return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL, |
| MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); |
| |
| return 0; |
| } |
| |
| /* Mount legacy cgroup hierarchy when cgroup namespaces are unsupported. */ |
| static int mount_legacy_cgns_unsupported( |
| const char *dest, |
| CGroupUnified unified_requested, bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| _cleanup_set_free_free_ Set *controllers = NULL; |
| const char *cgroup_root; |
| int r; |
| |
| cgroup_root = prefix_roota(dest, "/sys/fs/cgroup"); |
| |
| (void) mkdir_p(cgroup_root, 0755); |
| |
| /* Mount a tmpfs to /sys/fs/cgroup if it's not mounted there yet. */ |
| r = path_is_mount_point(cgroup_root, AT_SYMLINK_FOLLOW); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine if /sys/fs/cgroup is already mounted: %m"); |
| if (r == 0) { |
| _cleanup_free_ char *options = NULL; |
| |
| r = tmpfs_patch_options("mode=755", userns, uid_shift, uid_range, false, selinux_apifs_context, &options); |
| if (r < 0) |
| return log_oom(); |
| |
| r = mount_verbose(LOG_ERR, "tmpfs", cgroup_root, "tmpfs", |
| MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME, options); |
| if (r < 0) |
| return r; |
| } |
| |
| if (cg_all_unified() > 0) |
| goto skip_controllers; |
| |
| controllers = set_new(&string_hash_ops); |
| if (!controllers) |
| return log_oom(); |
| |
| r = cg_kernel_controllers(controllers); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine cgroup controllers: %m"); |
| |
| for (;;) { |
| _cleanup_free_ char *controller = NULL, *origin = NULL, *combined = NULL; |
| |
| controller = set_steal_first(controllers); |
| if (!controller) |
| break; |
| |
| origin = prefix_root("/sys/fs/cgroup/", controller); |
| if (!origin) |
| return log_oom(); |
| |
| r = readlink_malloc(origin, &combined); |
| if (r == -EINVAL) { |
| /* Not a symbolic link, but directly a single cgroup hierarchy */ |
| |
| r = mount_legacy_cgroup_hierarchy(dest, controller, controller, unified_requested, true); |
| if (r < 0) |
| return r; |
| |
| } else if (r < 0) |
| return log_error_errno(r, "Failed to read link %s: %m", origin); |
| else { |
| _cleanup_free_ char *target = NULL; |
| |
| target = prefix_root(dest, origin); |
| if (!target) |
| return log_oom(); |
| |
| /* A symbolic link, a combination of controllers in one hierarchy */ |
| |
| if (!filename_is_valid(combined)) { |
| log_warning("Ignoring invalid combined hierarchy %s.", combined); |
| continue; |
| } |
| |
| r = mount_legacy_cgroup_hierarchy(dest, combined, combined, unified_requested, true); |
| if (r < 0) |
| return r; |
| |
| r = symlink_idempotent(combined, target); |
| if (r == -EINVAL) |
| return log_error_errno(r, "Invalid existing symlink for combined hierarchy: %m"); |
| if (r < 0) |
| return log_error_errno(r, "Failed to create symlink for combined hierarchy: %m"); |
| } |
| } |
| |
| skip_controllers: |
| r = mount_legacy_cgroup_hierarchy(dest, SYSTEMD_CGROUP_CONTROLLER, "systemd", unified_requested, false); |
| if (r < 0) |
| return r; |
| |
| return mount_verbose(LOG_ERR, NULL, cgroup_root, NULL, |
| MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_STRICTATIME|MS_RDONLY, "mode=755"); |
| } |
| |
| static int mount_unified_cgroups(const char *dest) { |
| const char *p; |
| int r; |
| |
| assert(dest); |
| |
| p = prefix_roota(dest, "/sys/fs/cgroup"); |
| |
| (void) mkdir_p(p, 0755); |
| |
| r = path_is_mount_point(p, AT_SYMLINK_FOLLOW); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine if %s is mounted already: %m", p); |
| if (r > 0) { |
| p = prefix_roota(dest, "/sys/fs/cgroup/cgroup.procs"); |
| if (access(p, F_OK) >= 0) |
| return 0; |
| if (errno != ENOENT) |
| return log_error_errno(errno, "Failed to determine if mount point %s contains the unified cgroup hierarchy: %m", p); |
| |
| log_error("%s is already mounted but not a unified cgroup hierarchy. Refusing.", p); |
| return -EINVAL; |
| } |
| |
| return mount_verbose(LOG_ERR, "cgroup", p, "cgroup2", MS_NOSUID|MS_NOEXEC|MS_NODEV, NULL); |
| } |
| |
| int mount_cgroups( |
| const char *dest, |
| CGroupUnified unified_requested, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context, |
| bool use_cgns) { |
| |
| if (unified_requested >= CGROUP_UNIFIED_ALL) |
| return mount_unified_cgroups(dest); |
| else if (use_cgns) |
| return mount_legacy_cgns_supported(unified_requested, userns, uid_shift, uid_range, selinux_apifs_context); |
| |
| return mount_legacy_cgns_unsupported(dest, unified_requested, userns, uid_shift, uid_range, selinux_apifs_context); |
| } |
| |
| int mount_systemd_cgroup_writable( |
| const char *dest, |
| CGroupUnified unified_requested) { |
| |
| _cleanup_free_ char *own_cgroup_path = NULL; |
| const char *systemd_root, *systemd_own; |
| int r; |
| |
| assert(dest); |
| |
| r = cg_pid_get_path(NULL, 0, &own_cgroup_path); |
| if (r < 0) |
| return log_error_errno(r, "Failed to determine our own cgroup path: %m"); |
| |
| /* If we are living in the top-level, then there's nothing to do... */ |
| if (path_equal(own_cgroup_path, "/")) |
| return 0; |
| |
| if (unified_requested >= CGROUP_UNIFIED_ALL) { |
| systemd_own = strjoina(dest, "/sys/fs/cgroup", own_cgroup_path); |
| systemd_root = prefix_roota(dest, "/sys/fs/cgroup"); |
| } else { |
| systemd_own = strjoina(dest, "/sys/fs/cgroup/systemd", own_cgroup_path); |
| systemd_root = prefix_roota(dest, "/sys/fs/cgroup/systemd"); |
| } |
| |
| /* Make our own cgroup a (writable) bind mount */ |
| r = mount_verbose(LOG_ERR, systemd_own, systemd_own, NULL, MS_BIND, NULL); |
| if (r < 0) |
| return r; |
| |
| /* And then remount the systemd cgroup root read-only */ |
| return mount_verbose(LOG_ERR, NULL, systemd_root, NULL, |
| MS_BIND|MS_REMOUNT|MS_NOSUID|MS_NOEXEC|MS_NODEV|MS_RDONLY, NULL); |
| } |
| |
| int setup_volatile_state( |
| const char *directory, |
| VolatileMode mode, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| _cleanup_free_ char *buf = NULL; |
| const char *p, *options; |
| int r; |
| |
| assert(directory); |
| |
| if (mode != VOLATILE_STATE) |
| return 0; |
| |
| /* --volatile=state means we simply overmount /var |
| with a tmpfs, and the rest read-only. */ |
| |
| r = bind_remount_recursive(directory, true, 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=755"; |
| r = tmpfs_patch_options(options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| options = buf; |
| |
| return mount_verbose(LOG_ERR, "tmpfs", p, "tmpfs", MS_STRICTATIME, options); |
| } |
| |
| int setup_volatile( |
| const char *directory, |
| VolatileMode mode, |
| bool userns, uid_t uid_shift, uid_t uid_range, |
| const char *selinux_apifs_context) { |
| |
| bool tmpfs_mounted = false, bind_mounted = false; |
| char template[] = "/tmp/nspawn-volatile-XXXXXX"; |
| _cleanup_free_ char *buf = NULL; |
| const char *f, *t, *options; |
| int r; |
| |
| assert(directory); |
| |
| if (mode != VOLATILE_YES) |
| return 0; |
| |
| /* --volatile=yes means we mount a tmpfs to the root dir, and |
| the original /usr to use inside it, and that read-only. */ |
| |
| if (!mkdtemp(template)) |
| return log_error_errno(errno, "Failed to create temporary directory: %m"); |
| |
| options = "mode=755"; |
| r = tmpfs_patch_options(options, userns, uid_shift, uid_range, false, selinux_apifs_context, &buf); |
| if (r < 0) |
| return log_oom(); |
| if (r > 0) |
| options = buf; |
| |
| r = mount_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_verbose(LOG_ERR, f, t, NULL, MS_BIND|MS_REC, NULL); |
| if (r < 0) |
| goto fail; |
| |
| bind_mounted = true; |
| |
| r = bind_remount_recursive(t, true, NULL); |
| if (r < 0) { |
| log_error_errno(r, "Failed to remount %s read-only: %m", t); |
| goto fail; |
| } |
| |
| r = mount_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(t); |
| |
| if (tmpfs_mounted) |
| (void) umount_verbose(template); |
| (void) rmdir(template); |
| return r; |
| } |
| |
| VolatileMode volatile_mode_from_string(const char *s) { |
| int b; |
| |
| if (isempty(s)) |
| return _VOLATILE_MODE_INVALID; |
| |
| b = parse_boolean(s); |
| if (b > 0) |
| return VOLATILE_YES; |
| if (b == 0) |
| return VOLATILE_NO; |
| |
| if (streq(s, "state")) |
| return VOLATILE_STATE; |
| |
| return _VOLATILE_MODE_INVALID; |
| } |