/*** 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 "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, } 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. */ #ifdef HAVE_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 }, #ifdef HAVE_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 }, #ifdef HAVE_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", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, cg_is_unified_wanted, MNT_FATAL|MNT_IN_CONTAINER }, { "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/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 }, #ifdef ENABLE_EFI { "efivarfs", "/sys/firmware/efi/efivars", "efivarfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, is_efi_boot, MNT_NONE }, #endif { "kdbusfs", "/sys/fs/kdbus", "kdbusfs", NULL, MS_NOSUID|MS_NOEXEC|MS_NODEV, is_kdbus_wanted, MNT_IN_CONTAINER }, }; /* 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; assert(p); 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, AT_SYMLINK_FOLLOW); if (r < 0 && r != -ENOENT) { log_full_errno((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, 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((p->mode & MNT_FATAL) ? LOG_ERR : LOG_DEBUG, 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); 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. */ 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 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 defined(HAVE_SELINUX) || defined(HAVE_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 defined(HAVE_SELINUX) || defined(HAVE_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("/run", nftw_cb, 64, FTW_MOUNT|FTW_PHYS|FTW_ACTIONRETVAL); after_relabel = now(CLOCK_MONOTONIC); log_info("Relabelled /dev and /run 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. */ 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. */ mkdir_label("/run/systemd", 0755); mkdir_label("/run/systemd/system", 0755); mkdir_label("/run/systemd/inaccessible", 0000); return 0; }