/* SPDX-License-Identifier: LGPL-2.1-or-later */ #include #include #include #include #include #include #include "sd-bus.h" #include "build.h" #include "bus-locator.h" #include "bus-error.h" #include "bus-unit-util.h" #include "bus-util.h" #include "capability-util.h" #include "chase.h" #include "constants.h" #include "devnum-util.h" #include "discover-image.h" #include "dissect-image.h" #include "env-util.h" #include "escape.h" #include "extension-util.h" #include "fd-util.h" #include "fileio.h" #include "format-table.h" #include "fs-util.h" #include "hashmap.h" #include "initrd-util.h" #include "log.h" #include "main-func.h" #include "missing_magic.h" #include "mkdir.h" #include "mount-util.h" #include "mountpoint-util.h" #include "os-util.h" #include "pager.h" #include "parse-argument.h" #include "parse-util.h" #include "pretty-print.h" #include "process-util.h" #include "sort-util.h" #include "terminal-util.h" #include "user-util.h" #include "varlink.h" #include "varlink-io.systemd.sysext.h" #include "verbs.h" static char **arg_hierarchies = NULL; /* "/usr" + "/opt" by default for sysext and /etc by default for confext */ static char *arg_root = NULL; static JsonFormatFlags arg_json_format_flags = JSON_FORMAT_OFF; static PagerFlags arg_pager_flags = 0; static bool arg_legend = true; static bool arg_force = false; static bool arg_no_reload = false; static int arg_noexec = -1; static ImagePolicy *arg_image_policy = NULL; static bool arg_varlink = false; /* Is set to IMAGE_CONFEXT when systemd is called with the confext functionality instead of the default */ static ImageClass arg_image_class = IMAGE_SYSEXT; STATIC_DESTRUCTOR_REGISTER(arg_hierarchies, strv_freep); STATIC_DESTRUCTOR_REGISTER(arg_root, freep); STATIC_DESTRUCTOR_REGISTER(arg_image_policy, image_policy_freep); /* Helper struct for naming simplicity and reusability */ static const struct { const char *dot_directory_name; const char *directory_name; const char *short_identifier; const char *short_identifier_plural; const char *level_env; const char *scope_env; const char *name_env; const ImagePolicy *default_image_policy; unsigned long default_mount_flags; } image_class_info[_IMAGE_CLASS_MAX] = { [IMAGE_SYSEXT] = { .dot_directory_name = ".systemd-sysext", .directory_name = "systemd-sysext", .short_identifier = "sysext", .short_identifier_plural = "extensions", .level_env = "SYSEXT_LEVEL", .scope_env = "SYSEXT_SCOPE", .name_env = "SYSTEMD_SYSEXT_HIERARCHIES", .default_image_policy = &image_policy_sysext, .default_mount_flags = MS_RDONLY|MS_NODEV, }, [IMAGE_CONFEXT] = { .dot_directory_name = ".systemd-confext", .directory_name = "systemd-confext", .short_identifier = "confext", .short_identifier_plural = "confexts", .level_env = "CONFEXT_LEVEL", .scope_env = "CONFEXT_SCOPE", .name_env = "SYSTEMD_CONFEXT_HIERARCHIES", .default_image_policy = &image_policy_confext, .default_mount_flags = MS_RDONLY|MS_NODEV|MS_NOSUID|MS_NOEXEC, } }; static int is_our_mount_point( ImageClass image_class, const char *p) { _cleanup_free_ char *buf = NULL, *f = NULL; struct stat st; dev_t dev; int r; assert(p); r = path_is_mount_point(p, NULL, 0); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s' doesn't exist.", p); return false; } if (r < 0) return log_error_errno(r, "Failed to determine whether '%s' is a mount point: %m", p); if (r == 0) { log_debug("Hierarchy '%s' is not a mount point, skipping.", p); return false; } /* So we know now that it's a mount point. Now let's check if it's one of ours, so that we don't * accidentally unmount the user's own /usr/ but just the mounts we established ourselves. We do this * check by looking into the metadata directory we place in merged mounts: if the file * ../dev contains the major/minor device pair of the mount we have a good reason to * believe this is one of our mounts. This thorough check has the benefit that we aren't easily * confused if people tar up one of our merged trees and untar them elsewhere where we might mistake * them for a live sysext tree. */ f = path_join(p, image_class_info[image_class].dot_directory_name, "dev"); if (!f) return log_oom(); r = read_one_line_file(f, &buf); if (r == -ENOENT) { log_debug("Hierarchy '%s' does not carry a %s/dev file, not a merged tree.", p, image_class_info[image_class].dot_directory_name); return false; } if (r < 0) return log_error_errno(r, "Failed to determine whether hierarchy '%s' contains '%s/dev': %m", p, image_class_info[image_class].dot_directory_name); r = parse_devnum(buf, &dev); if (r < 0) return log_error_errno(r, "Failed to parse device major/minor stored in '%s/dev' file on '%s': %m", image_class_info[image_class].dot_directory_name, p); if (lstat(p, &st) < 0) return log_error_errno(r, "Failed to stat %s: %m", p); if (st.st_dev != dev) { log_debug("Hierarchy '%s' reports a different device major/minor than what we are seeing, assuming offline copy.", p); return false; } return true; } static int need_reload( ImageClass image_class, char **hierarchies, bool no_reload) { /* Parse the mounted images to find out if we need to reload the daemon. */ int r; if (no_reload) return false; STRV_FOREACH(p, hierarchies) { _cleanup_free_ char *f = NULL, *buf = NULL, *resolved = NULL; _cleanup_strv_free_ char **mounted_extensions = NULL; r = chase(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); continue; } if (r < 0) { log_warning_errno(r, "Failed to resolve path to hierarchy '%s%s': %m, ignoring.", strempty(arg_root), *p); continue; } r = is_our_mount_point(image_class, resolved); if (r < 0) return r; if (!r) continue; f = path_join(resolved, image_class_info[image_class].dot_directory_name, image_class_info[image_class].short_identifier_plural); if (!f) return log_oom(); r = read_full_file(f, &buf, NULL); if (r < 0) return log_error_errno(r, "Failed to open '%s': %m", f); mounted_extensions = strv_split_newlines(buf); if (!mounted_extensions) return log_oom(); STRV_FOREACH(extension, mounted_extensions) { _cleanup_strv_free_ char **extension_release = NULL; const char *extension_reload_manager = NULL; int b; r = load_extension_release_pairs(arg_root, image_class, *extension, /* relax_extension_release_check */ true, &extension_release); if (r < 0) { log_debug_errno(r, "Failed to parse extension-release metadata of %s, ignoring: %m", *extension); continue; } extension_reload_manager = strv_env_pairs_get(extension_release, "EXTENSION_RELOAD_MANAGER"); if (isempty(extension_reload_manager)) continue; b = parse_boolean(extension_reload_manager); if (b < 0) { log_warning_errno(b, "Failed to parse the extension metadata to know if the manager needs to be reloaded, ignoring: %m"); continue; } if (b) /* If at least one extension wants a reload, we reload. */ return true; } } return false; } static int daemon_reload(void) { _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; int r; r = bus_connect_system_systemd(&bus); if (r < 0) return log_error_errno(r, "Failed to get D-Bus connection: %m"); return bus_service_manager_reload(bus); } static int unmerge_hierarchy( ImageClass image_class, const char *p) { int r; assert(p); for (;;) { /* We only unmount /usr/ if it is a mount point and really one of ours, in order not to break * systems where /usr/ is a mount point of its own already. */ r = is_our_mount_point(image_class, p); if (r < 0) return r; if (r == 0) break; r = umount_verbose(LOG_ERR, p, MNT_DETACH|UMOUNT_NOFOLLOW); if (r < 0) return log_error_errno(r, "Failed to unmount file system '%s': %m", p); log_info("Unmerged '%s'.", p); } return 0; } static int unmerge( ImageClass image_class, char **hierarchies, bool no_reload) { int r, ret = 0; bool need_to_reload; r = need_reload(image_class, hierarchies, no_reload); if (r < 0) return r; need_to_reload = r > 0; STRV_FOREACH(p, hierarchies) { _cleanup_free_ char *resolved = NULL; r = chase(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); continue; } if (r < 0) { log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); if (ret == 0) ret = r; continue; } r = unmerge_hierarchy(image_class, resolved); if (r < 0 && ret == 0) ret = r; } if (need_to_reload) { r = daemon_reload(); if (r < 0) return r; } return ret; } static int verb_unmerge(int argc, char **argv, void *userdata) { int r; r = have_effective_cap(CAP_SYS_ADMIN); if (r < 0) return log_error_errno(r, "Failed to check if we have enough privileges: %m"); if (r == 0) return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); return unmerge(arg_image_class, arg_hierarchies, arg_no_reload); } static int parse_image_class_parameter(Varlink *link, const char *value, ImageClass *image_class, char ***hierarchies) { _cleanup_strv_free_ char **h = NULL; ImageClass c; int r; assert(link); assert(image_class); if (!value) return 0; c = image_class_from_string(value); if (!IN_SET(c, IMAGE_SYSEXT, IMAGE_CONFEXT)) return varlink_errorb(link, VARLINK_ERROR_INVALID_PARAMETER, JSON_BUILD_OBJECT(JSON_BUILD_PAIR_STRING("parameter", "class"))); if (hierarchies) { r = parse_env_extension_hierarchies(&h, image_class_info[c].name_env); if (r < 0) return log_error_errno(r, "Failed to parse environment variable: %m"); strv_free_and_replace(*hierarchies, h); } *image_class = c; return 0; } typedef struct MethodUnmergeParameters { const char *class; int no_reload; } MethodUnmergeParameters; static int vl_method_unmerge(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { static const JsonDispatch dispatch_table[] = { { "class", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(MethodUnmergeParameters, class), 0 }, { "noReload", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(MethodUnmergeParameters, no_reload), 0 }, {} }; MethodUnmergeParameters p = { .no_reload = -1, }; _cleanup_strv_free_ char **hierarchies = NULL; ImageClass image_class = arg_image_class; int r; assert(link); r = varlink_dispatch(link, parameters, dispatch_table, &p); if (r != 0) return r; r = parse_image_class_parameter(link, p.class, &image_class, &hierarchies); if (r < 0) return r; r = unmerge(image_class, hierarchies ?: arg_hierarchies, p.no_reload >= 0 ? p.no_reload : arg_no_reload); if (r < 0) return r; return varlink_reply(link, NULL); } static int verb_status(int argc, char **argv, void *userdata) { _cleanup_(table_unrefp) Table *t = NULL; int r, ret = 0; t = table_new("hierarchy", "extensions", "since"); if (!t) return log_oom(); table_set_ersatz_string(t, TABLE_ERSATZ_DASH); STRV_FOREACH(p, arg_hierarchies) { _cleanup_free_ char *resolved = NULL, *f = NULL, *buf = NULL; _cleanup_strv_free_ char **l = NULL; struct stat st; r = chase(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); continue; } if (r < 0) { log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); goto inner_fail; } r = is_our_mount_point(arg_image_class, resolved); if (r < 0) goto inner_fail; if (r == 0) { r = table_add_many( t, TABLE_PATH, *p, TABLE_STRING, "none", TABLE_SET_COLOR, ansi_grey(), TABLE_EMPTY); if (r < 0) return table_log_add_error(r); continue; } f = path_join(resolved, image_class_info[arg_image_class].dot_directory_name, image_class_info[arg_image_class].short_identifier_plural); if (!f) return log_oom(); r = read_full_file(f, &buf, NULL); if (r < 0) return log_error_errno(r, "Failed to open '%s': %m", f); l = strv_split_newlines(buf); if (!l) return log_oom(); if (stat(*p, &st) < 0) return log_error_errno(r, "Failed to stat() '%s': %m", *p); r = table_add_many( t, TABLE_PATH, *p, TABLE_STRV, l, TABLE_TIMESTAMP, timespec_load(&st.st_mtim)); if (r < 0) return table_log_add_error(r); continue; inner_fail: if (ret == 0) ret = r; } (void) table_set_sort(t, (size_t) 0); r = table_print_with_pager(t, arg_json_format_flags, arg_pager_flags, arg_legend); if (r < 0) return r; return ret; } static int mount_overlayfs( ImageClass image_class, int noexec, const char *where, char **layers) { _cleanup_free_ char *options = NULL; bool separator = false; unsigned long flags; int r; assert(where); options = strdup("lowerdir="); if (!options) return log_oom(); STRV_FOREACH(l, layers) { _cleanup_free_ char *escaped = NULL; escaped = shell_escape(*l, ",:"); if (!escaped) return log_oom(); if (!strextend(&options, separator ? ":" : "", escaped)) return log_oom(); separator = true; } flags = image_class_info[image_class].default_mount_flags; if (noexec >= 0) SET_FLAG(flags, MS_NOEXEC, noexec); /* Now mount the actual overlayfs */ r = mount_nofollow_verbose(LOG_ERR, image_class_info[image_class].short_identifier, where, "overlay", flags, options); if (r < 0) return r; return 0; } static int merge_hierarchy( ImageClass image_class, const char *hierarchy, int noexec, char **extensions, char **paths, const char *meta_path, const char *overlay_path) { _cleanup_free_ char *resolved_hierarchy = NULL, *f = NULL, *buf = NULL; _cleanup_strv_free_ char **layers = NULL; struct stat st; int r; assert(hierarchy); assert(meta_path); assert(overlay_path); /* Resolve the path of the host's version of the hierarchy, i.e. what we want to use as lowest layer * in the overlayfs stack. */ r = chase(hierarchy, arg_root, CHASE_PREFIX_ROOT, &resolved_hierarchy, NULL); if (r == -ENOENT) log_debug_errno(r, "Hierarchy '%s' on host doesn't exist, not merging.", hierarchy); else if (r < 0) return log_error_errno(r, "Failed to resolve host hierarchy '%s': %m", hierarchy); else { r = dir_is_empty(resolved_hierarchy, /* ignore_hidden_or_backup= */ false); if (r < 0) return log_error_errno(r, "Failed to check if host hierarchy '%s' is empty: %m", resolved_hierarchy); if (r > 0) { log_debug("Host hierarchy '%s' is empty, not merging.", resolved_hierarchy); resolved_hierarchy = mfree(resolved_hierarchy); } } /* Let's generate a metadata file that lists all extensions we took into account for this * hierarchy. We include this in the final fs, to make things nicely discoverable and * recognizable. */ f = path_join(meta_path, image_class_info[image_class].dot_directory_name, image_class_info[image_class].short_identifier_plural); if (!f) return log_oom(); buf = strv_join(extensions, "\n"); if (!buf) return log_oom(); r = write_string_file(f, buf, WRITE_STRING_FILE_CREATE|WRITE_STRING_FILE_MKDIR_0755); if (r < 0) return log_error_errno(r, "Failed to write extension meta file '%s': %m", f); /* Put the meta path (i.e. our synthesized stuff) at the top of the layer stack */ layers = strv_new(meta_path); if (!layers) return log_oom(); /* Put the extensions in the middle */ STRV_FOREACH(p, paths) { _cleanup_free_ char *resolved = NULL; r = chase(hierarchy, *p, CHASE_PREFIX_ROOT, &resolved, NULL); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s' in extension '%s' doesn't exist, not merging.", hierarchy, *p); continue; } if (r < 0) return log_error_errno(r, "Failed to resolve hierarchy '%s' in extension '%s': %m", hierarchy, *p); r = dir_is_empty(resolved, /* ignore_hidden_or_backup= */ false); if (r < 0) return log_error_errno(r, "Failed to check if hierarchy '%s' in extension '%s' is empty: %m", resolved, *p); if (r > 0) { log_debug("Hierarchy '%s' in extension '%s' is empty, not merging.", hierarchy, *p); continue; } r = strv_consume(&layers, TAKE_PTR(resolved)); if (r < 0) return log_oom(); } if (!layers[1]) /* No extension with files in this hierarchy? Then don't do anything. */ return 0; if (resolved_hierarchy) { /* Add the host hierarchy as last (lowest) layer in the stack */ r = strv_consume(&layers, TAKE_PTR(resolved_hierarchy)); if (r < 0) return log_oom(); } r = mkdir_p(overlay_path, 0700); if (r < 0) return log_error_errno(r, "Failed to make directory '%s': %m", overlay_path); r = mount_overlayfs(image_class, noexec, overlay_path, layers); if (r < 0) return r; /* The overlayfs superblock is read-only. Let's also mark the bind mount read-only. Extra turbo safety 😎 */ r = bind_remount_recursive(overlay_path, MS_RDONLY, MS_RDONLY, NULL); if (r < 0) return log_error_errno(r, "Failed to make bind mount '%s' read-only: %m", overlay_path); /* Now we have mounted the new file system. Let's now figure out its .st_dev field, and make that * available in the metadata directory. This is useful to detect whether the metadata dir actually * belongs to the fs it is found on: if .st_dev of the top-level mount matches it, it's pretty likely * we are looking at a live tree, and not an unpacked tar or so of one. */ if (stat(overlay_path, &st) < 0) return log_error_errno(r, "Failed to stat mount '%s': %m", overlay_path); free(f); f = path_join(meta_path, image_class_info[image_class].dot_directory_name, "dev"); if (!f) return log_oom(); r = write_string_file(f, FORMAT_DEVNUM(st.st_dev), WRITE_STRING_FILE_CREATE); if (r < 0) return log_error_errno(r, "Failed to write '%s': %m", f); /* Make sure the top-level dir has an mtime marking the point we established the merge */ if (utimensat(AT_FDCWD, meta_path, NULL, AT_SYMLINK_NOFOLLOW) < 0) return log_error_errno(r, "Failed fix mtime of '%s': %m", meta_path); return 1; } static int strverscmp_improvedp(char *const* a, char *const* b) { /* usable in qsort() for sorting a string array with strverscmp_improved() */ return strverscmp_improved(*a, *b); } static const ImagePolicy *pick_image_policy(const Image *img) { assert(img); assert(img->path); /* Explicitly specified policy always wins */ if (arg_image_policy) return arg_image_policy; /* If located in /.extra/sysext/ in the initrd, then it was placed there by systemd-stub, and was * picked up from an untrusted ESP. Thus, require a stricter policy by default for them. (For the * other directories we assume the appropriate level of trust was already established already. */ if (in_initrd() && path_startswith(img->path, "/.extra/sysext/")) return &image_policy_sysext_strict; return image_class_info[img->class].default_image_policy; } static int merge_subprocess( ImageClass image_class, char **hierarchies, bool force, int noexec, Hashmap *images, const char *workspace) { _cleanup_free_ char *host_os_release_id = NULL, *host_os_release_version_id = NULL, *host_os_release_api_level = NULL, *buf = NULL; _cleanup_strv_free_ char **extensions = NULL, **paths = NULL; size_t n_extensions = 0; unsigned n_ignored = 0; Image *img; int r; /* Mark the whole of /run as MS_SLAVE, so that we can mount stuff below it that doesn't show up on * the host otherwise. */ r = mount_nofollow_verbose(LOG_ERR, NULL, "/run", NULL, MS_SLAVE|MS_REC, NULL); if (r < 0) return log_error_errno(r, "Failed to remount /run/ MS_SLAVE: %m"); /* Let's create the workspace if it's missing */ r = mkdir_p(workspace, 0700); if (r < 0) return log_error_errno(r, "Failed to create '%s': %m", workspace); /* Let's mount a tmpfs to our workspace. This way we don't need to clean up the inodes we mount over, * but let the kernel do that entirely automatically, once our namespace dies. Note that this file * system won't be visible to anyone but us, since we opened our own namespace and then made the * /run/ hierarchy (which our workspace is contained in) MS_SLAVE, see above. */ r = mount_nofollow_verbose(LOG_ERR, image_class_info[image_class].short_identifier, workspace, "tmpfs", 0, "mode=0700"); if (r < 0) return r; /* Acquire host OS release info, so that we can compare it with the extension's data */ r = parse_os_release( arg_root, "ID", &host_os_release_id, "VERSION_ID", &host_os_release_version_id, image_class_info[image_class].level_env, &host_os_release_api_level); if (r < 0) return log_error_errno(r, "Failed to acquire 'os-release' data of OS tree '%s': %m", empty_to_root(arg_root)); if (isempty(host_os_release_id)) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "'ID' field not found or empty in 'os-release' data of OS tree '%s': %m", empty_to_root(arg_root)); /* Let's now mount all images */ HASHMAP_FOREACH(img, images) { _cleanup_free_ char *p = NULL; p = path_join(workspace, image_class_info[image_class].short_identifier_plural, img->name); if (!p) return log_oom(); r = mkdir_p(p, 0700); if (r < 0) return log_error_errno(r, "Failed to create %s: %m", p); switch (img->type) { case IMAGE_DIRECTORY: case IMAGE_SUBVOLUME: if (!force) { r = extension_has_forbidden_content(p); if (r < 0) return r; if (r > 0) { n_ignored++; continue; } } r = mount_nofollow_verbose(LOG_ERR, img->path, p, NULL, MS_BIND, NULL); if (r < 0) return r; /* Make this a read-only bind mount */ r = bind_remount_recursive(p, MS_RDONLY, MS_RDONLY, NULL); if (r < 0) return log_error_errno(r, "Failed to make bind mount '%s' read-only: %m", p); break; case IMAGE_RAW: case IMAGE_BLOCK: { _cleanup_(dissected_image_unrefp) DissectedImage *m = NULL; _cleanup_(loop_device_unrefp) LoopDevice *d = NULL; _cleanup_(verity_settings_done) VeritySettings verity_settings = VERITY_SETTINGS_DEFAULT; DissectImageFlags flags = DISSECT_IMAGE_READ_ONLY | DISSECT_IMAGE_GENERIC_ROOT | DISSECT_IMAGE_REQUIRE_ROOT | DISSECT_IMAGE_MOUNT_ROOT_ONLY | DISSECT_IMAGE_USR_NO_ROOT | DISSECT_IMAGE_ADD_PARTITION_DEVICES | DISSECT_IMAGE_PIN_PARTITION_DEVICES; r = verity_settings_load(&verity_settings, img->path, NULL, NULL); if (r < 0) return log_error_errno(r, "Failed to read verity artifacts for %s: %m", img->path); if (verity_settings.data_path) flags |= DISSECT_IMAGE_NO_PARTITION_TABLE; if (!force) flags |= DISSECT_IMAGE_VALIDATE_OS_EXT; r = loop_device_make_by_path( img->path, O_RDONLY, /* sector_size= */ UINT32_MAX, FLAGS_SET(flags, DISSECT_IMAGE_NO_PARTITION_TABLE) ? 0 : LO_FLAGS_PARTSCAN, LOCK_SH, &d); if (r < 0) return log_error_errno(r, "Failed to set up loopback device for %s: %m", img->path); r = dissect_loop_device_and_warn( d, &verity_settings, /* mount_options= */ NULL, pick_image_policy(img), flags, &m); if (r < 0) return r; r = dissected_image_load_verity_sig_partition( m, d->fd, &verity_settings); if (r < 0) return r; r = dissected_image_decrypt_interactively( m, NULL, &verity_settings, flags); if (r < 0) return r; r = dissected_image_mount_and_warn( m, p, /* uid_shift= */ UID_INVALID, /* uid_range= */ UID_INVALID, /* userns_fd= */ -EBADF, flags); if (r < 0 && r != -ENOMEDIUM) return r; if (r == -ENOMEDIUM && !force) { n_ignored++; continue; } r = dissected_image_relinquish(m); if (r < 0) return log_error_errno(r, "Failed to relinquish DM and loopback block devices: %m"); break; } default: assert_not_reached(); } if (force) log_debug("Force mode enabled, skipping version validation."); else { r = extension_release_validate( img->name, host_os_release_id, host_os_release_version_id, host_os_release_api_level, in_initrd() ? "initrd" : "system", image_extension_release(img, image_class), image_class); if (r < 0) return r; if (r == 0) { n_ignored++; continue; } } /* Nice! This one is an extension we want. */ r = strv_extend(&extensions, img->name); if (r < 0) return log_oom(); n_extensions ++; } /* Nothing left? Then shortcut things */ if (n_extensions == 0) { if (n_ignored > 0) log_info("No suitable extensions found (%u ignored due to incompatible image(s)).", n_ignored); else log_info("No extensions found."); return 0; } /* Order by version sort with strverscmp_improved() */ typesafe_qsort(extensions, n_extensions, strverscmp_improvedp); buf = strv_join(extensions, "', '"); if (!buf) return log_oom(); log_info("Using extensions '%s'.", buf); /* Build table of extension paths (in reverse order) */ paths = new0(char*, n_extensions + 1); if (!paths) return log_oom(); for (size_t k = 0; k < n_extensions; k++) { _cleanup_free_ char *p = NULL; assert_se(img = hashmap_get(images, extensions[n_extensions - 1 - k])); p = path_join(workspace, image_class_info[image_class].short_identifier_plural, img->name); if (!p) return log_oom(); paths[k] = TAKE_PTR(p); } /* Let's now unmerge the status quo ante, since to build the new overlayfs we need a reference to the * underlying fs. */ STRV_FOREACH(h, hierarchies) { _cleanup_free_ char *resolved = NULL; r = chase(*h, arg_root, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &resolved, NULL); if (r < 0) return log_error_errno(r, "Failed to resolve hierarchy '%s%s': %m", strempty(arg_root), *h); r = unmerge_hierarchy(image_class, resolved); if (r < 0) return r; } /* Create overlayfs mounts for all hierarchies */ STRV_FOREACH(h, hierarchies) { _cleanup_free_ char *meta_path = NULL, *overlay_path = NULL; meta_path = path_join(workspace, "meta", *h); /* The place where to store metadata about this instance */ if (!meta_path) return log_oom(); overlay_path = path_join(workspace, "overlay", *h); /* The resulting overlayfs instance */ if (!overlay_path) return log_oom(); r = merge_hierarchy( image_class, *h, noexec, extensions, paths, meta_path, overlay_path); if (r < 0) return r; } /* And move them all into place. This is where things appear in the host namespace */ STRV_FOREACH(h, hierarchies) { _cleanup_free_ char *p = NULL, *resolved = NULL; p = path_join(workspace, "overlay", *h); if (!p) return log_oom(); r = laccess(p, F_OK); if (r == -ENOENT) /* Hierarchy apparently was empty in all extensions, and wasn't mounted, ignoring. */ continue; if (r < 0) return log_error_errno(r, "Failed to check if '%s' exists: %m", p); r = chase(*h, arg_root, CHASE_PREFIX_ROOT|CHASE_NONEXISTENT, &resolved, NULL); if (r < 0) return log_error_errno(r, "Failed to resolve hierarchy '%s%s': %m", strempty(arg_root), *h); r = mkdir_p(resolved, 0755); if (r < 0) return log_error_errno(r, "Failed to create hierarchy mount point '%s': %m", resolved); r = mount_nofollow_verbose(LOG_ERR, p, resolved, NULL, MS_BIND, NULL); if (r < 0) return r; log_info("Merged extensions into '%s'.", resolved); } return 1; } static int merge(ImageClass image_class, char **hierarchies, bool force, bool no_reload, int noexec, Hashmap *images) { pid_t pid; int r; r = safe_fork("(sd-merge)", FORK_DEATHSIG_SIGTERM|FORK_LOG|FORK_NEW_MOUNTNS, &pid); if (r < 0) return log_error_errno(r, "Failed to fork off child: %m"); if (r == 0) { /* Child with its own mount namespace */ r = merge_subprocess(image_class, hierarchies, force, noexec, images, "/run/systemd/sysext"); if (r < 0) _exit(EXIT_FAILURE); /* Our namespace ceases to exist here, also implicitly detaching all temporary mounts we * created below /run. Nice! */ _exit(r > 0 ? EXIT_SUCCESS : 123); /* 123 means: didn't find any extensions */ } r = wait_for_terminate_and_check("(sd-merge)", pid, WAIT_LOG_ABNORMAL); if (r < 0) return r; if (r == 123) /* exit code 123 means: didn't do anything */ return 0; r = need_reload(image_class, hierarchies, no_reload); if (r < 0) return r; if (r > 0) { r = daemon_reload(); if (r < 0) return r; } return 1; } static int image_discover_and_read_metadata( ImageClass image_class, Hashmap **ret_images) { _cleanup_hashmap_free_ Hashmap *images = NULL; Image *img; int r; assert(ret_images); images = hashmap_new(&image_hash_ops); if (!images) return log_oom(); r = image_discover(image_class, arg_root, images); if (r < 0) return log_error_errno(r, "Failed to discover images: %m"); HASHMAP_FOREACH(img, images) { r = image_read_metadata(img, image_class_info[image_class].default_image_policy); if (r < 0) return log_error_errno(r, "Failed to read metadata for image %s: %m", img->name); } *ret_images = TAKE_PTR(images); return 0; } static int look_for_merged_hierarchies( ImageClass image_class, char **hierarchies, const char **ret_which) { int r; assert(ret_which); /* In merge mode fail if things are already merged. (In --refresh mode below we'll unmerge if we find * things are already merged...) */ STRV_FOREACH(p, hierarchies) { _cleanup_free_ char *resolved = NULL; r = chase(*p, arg_root, CHASE_PREFIX_ROOT, &resolved, NULL); if (r == -ENOENT) { log_debug_errno(r, "Hierarchy '%s%s' does not exist, ignoring.", strempty(arg_root), *p); continue; } if (r < 0) return log_error_errno(r, "Failed to resolve path to hierarchy '%s%s': %m", strempty(arg_root), *p); r = is_our_mount_point(image_class, resolved); if (r < 0) return r; if (r > 0) { *ret_which = *p; return 1; } } *ret_which = NULL; return 0; } static int verb_merge(int argc, char **argv, void *userdata) { _cleanup_hashmap_free_ Hashmap *images = NULL; const char *which; int r; r = have_effective_cap(CAP_SYS_ADMIN); if (r < 0) return log_error_errno(r, "Failed to check if we have enough privileges: %m"); if (r == 0) return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); r = image_discover_and_read_metadata(arg_image_class, &images); if (r < 0) return r; r = look_for_merged_hierarchies(arg_image_class, arg_hierarchies, &which); if (r < 0) return r; if (r > 0) return log_error_errno(SYNTHETIC_ERRNO(EBUSY), "Hierarchy '%s' is already merged.", which); return merge(arg_image_class, arg_hierarchies, arg_force, arg_no_reload, arg_noexec, images); } typedef struct MethodMergeParameters { const char *class; int force; int no_reload; int noexec; } MethodMergeParameters; static int parse_merge_parameters(Varlink *link, JsonVariant *parameters, MethodMergeParameters *p) { static const JsonDispatch dispatch_table[] = { { "class", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(MethodMergeParameters, class), 0 }, { "force", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(MethodMergeParameters, force), 0 }, { "noReload", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(MethodMergeParameters, no_reload), 0 }, { "noexec", JSON_VARIANT_BOOLEAN, json_dispatch_boolean, offsetof(MethodMergeParameters, noexec), 0 }, {} }; assert(link); assert(parameters); assert(p); return varlink_dispatch(link, parameters, dispatch_table, p); } static int vl_method_merge(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { _cleanup_hashmap_free_ Hashmap *images = NULL; MethodMergeParameters p = { .force = -1, .no_reload = -1, .noexec = -1, }; _cleanup_strv_free_ char **hierarchies = NULL; ImageClass image_class = arg_image_class; int r; assert(link); r = parse_merge_parameters(link, parameters, &p); if (r != 0) return r; r = parse_image_class_parameter(link, p.class, &image_class, &hierarchies); if (r < 0) return r; r = image_discover_and_read_metadata(image_class, &images); if (r < 0) return r; const char *which; r = look_for_merged_hierarchies( image_class, hierarchies ?: arg_hierarchies, &which); if (r < 0) return r; if (r > 0) return varlink_errorb(link, "io.systemd.sysext.AlreadyMerged", JSON_BUILD_OBJECT(JSON_BUILD_PAIR_STRING("hierarchy", which))); r = merge(image_class, hierarchies ?: arg_hierarchies, p.force >= 0 ? p.force : arg_force, p.no_reload >= 0 ? p.no_reload : arg_no_reload, p.noexec >= 0 ? p.noexec : arg_noexec, images); if (r < 0) return r; return varlink_reply(link, NULL); } static int refresh( ImageClass image_class, char **hierarchies, bool force, bool no_reload, int noexec) { _cleanup_hashmap_free_ Hashmap *images = NULL; int r; r = image_discover_and_read_metadata(image_class, &images); if (r < 0) return r; /* Returns > 0 if it did something, i.e. a new overlayfs is mounted now. When it does so it * implicitly unmounts any overlayfs placed there before. Returns == 0 if it did nothing, i.e. no * extension images found. In this case the old overlayfs remains in place if there was one. */ r = merge(image_class, hierarchies, force, no_reload, noexec, images); if (r < 0) return r; if (r == 0) /* No images found? Then unmerge. The goal of --refresh is after all that after having * called there's a guarantee that the merge status matches the installed extensions. */ r = unmerge(image_class, hierarchies, no_reload); /* Net result here is that: * * 1. If an overlayfs was mounted before and no extensions exist anymore, we'll have unmerged things. * * 2. If an overlayfs was mounted before, and there are still extensions installed' we'll have * unmerged and then merged things again. * * 3. If an overlayfs so far wasn't mounted, and there are extensions installed, we'll have it * mounted now. * * 4. If there was no overlayfs mount so far, and no extensions installed, we implement a NOP. */ return 0; } static int verb_refresh(int argc, char **argv, void *userdata) { int r; r = have_effective_cap(CAP_SYS_ADMIN); if (r < 0) return log_error_errno(r, "Failed to check if we have enough privileges: %m"); if (r == 0) return log_error_errno(SYNTHETIC_ERRNO(EPERM), "Need to be privileged."); return refresh(arg_image_class, arg_hierarchies, arg_force, arg_no_reload, arg_noexec); } static int vl_method_refresh(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { MethodMergeParameters p = { .force = -1, .no_reload = -1, .noexec = -1, }; _cleanup_strv_free_ char **hierarchies = NULL; ImageClass image_class = arg_image_class; int r; assert(link); r = parse_merge_parameters(link, parameters, &p); if (r != 0) return r; r = parse_image_class_parameter(link, p.class, &image_class, &hierarchies); if (r < 0) return r; r = refresh(image_class, hierarchies ?: arg_hierarchies, p.force >= 0 ? p.force : arg_force, p.no_reload >= 0 ? p.no_reload : arg_no_reload, p.noexec >= 0 ? p.noexec : arg_noexec); if (r < 0) return r; return varlink_reply(link, NULL); } static int verb_list(int argc, char **argv, void *userdata) { _cleanup_hashmap_free_ Hashmap *images = NULL; _cleanup_(table_unrefp) Table *t = NULL; Image *img; int r; images = hashmap_new(&image_hash_ops); if (!images) return log_oom(); r = image_discover(arg_image_class, arg_root, images); if (r < 0) return log_error_errno(r, "Failed to discover images: %m"); if ((arg_json_format_flags & JSON_FORMAT_OFF) && hashmap_isempty(images)) { log_info("No OS extensions found."); return 0; } t = table_new("name", "type", "path", "time"); if (!t) return log_oom(); HASHMAP_FOREACH(img, images) { r = table_add_many( t, TABLE_STRING, img->name, TABLE_STRING, image_type_to_string(img->type), TABLE_PATH, img->path, TABLE_TIMESTAMP, img->mtime != 0 ? img->mtime : img->crtime); if (r < 0) return table_log_add_error(r); } (void) table_set_sort(t, (size_t) 0); return table_print_with_pager(t, arg_json_format_flags, arg_pager_flags, arg_legend); } typedef struct MethodListParameters { const char *class; } MethodListParameters; static int vl_method_list(Varlink *link, JsonVariant *parameters, VarlinkMethodFlags flags, void *userdata) { static const JsonDispatch dispatch_table[] = { { "class", JSON_VARIANT_STRING, json_dispatch_const_string, offsetof(MethodListParameters, class), 0 }, {} }; MethodListParameters p = { }; _cleanup_(json_variant_unrefp) JsonVariant *v = NULL; _cleanup_hashmap_free_ Hashmap *images = NULL; ImageClass image_class = arg_image_class; Image *img; int r; assert(link); r = varlink_dispatch(link, parameters, dispatch_table, &p); if (r != 0) return r; r = parse_image_class_parameter(link, p.class, &image_class, NULL); if (r < 0) return r; images = hashmap_new(&image_hash_ops); if (!images) return -ENOMEM; r = image_discover(image_class, arg_root, images); if (r < 0) return r; HASHMAP_FOREACH(img, images) { if (v) { /* Send previous item with more=true */ r = varlink_notify(link, v); if (r < 0) return r; } v = json_variant_unref(v); r = image_to_json(img, &v); if (r < 0) return r; } if (v) /* Send final item with more=false */ return varlink_reply(link, v); return varlink_error(link, "io.systemd.sysext.NoImagesFound", NULL); } static int verb_help(int argc, char **argv, void *userdata) { _cleanup_free_ char *link = NULL; int r; r = terminal_urlify_man("systemd-sysext", "8", &link); if (r < 0) return log_oom(); printf("%1$s [OPTIONS...] COMMAND\n" "\n%5$sMerge extension images into /usr/ and /opt/ hierarchies for\n" " sysext and into the /etc/ hierarchy for confext.%6$s\n" " status Show current merge status (default)\n" " merge Merge extensions into relevant hierarchies\n" " unmerge Unmerge extensions from relevant hierarchies\n" " refresh Unmerge/merge extensions again\n" " list List installed extensions\n" " -h --help Show this help\n" " --version Show package version\n" "\n%3$sOptions:%4$s\n" " --no-pager Do not pipe output into a pager\n" " --no-legend Do not show the headers and footers\n" " --root=PATH Operate relative to root path\n" " --json=pretty|short|off\n" " Generate JSON output\n" " --force Ignore version incompatibilities\n" " --no-reload Do not reload the service manager\n" " --image-policy=POLICY\n" " Specify disk image dissection policy\n" " --noexec=BOOL Whether to mount extension overlay with noexec\n" "\nSee the %2$s for details.\n", program_invocation_short_name, link, ansi_underline(), ansi_normal(), ansi_highlight(), ansi_normal()); return 0; } static int parse_argv(int argc, char *argv[]) { enum { ARG_VERSION = 0x100, ARG_NO_PAGER, ARG_NO_LEGEND, ARG_ROOT, ARG_JSON, ARG_FORCE, ARG_IMAGE_POLICY, ARG_NOEXEC, ARG_NO_RELOAD, }; static const struct option options[] = { { "help", no_argument, NULL, 'h' }, { "version", no_argument, NULL, ARG_VERSION }, { "no-pager", no_argument, NULL, ARG_NO_PAGER }, { "no-legend", no_argument, NULL, ARG_NO_LEGEND }, { "root", required_argument, NULL, ARG_ROOT }, { "json", required_argument, NULL, ARG_JSON }, { "force", no_argument, NULL, ARG_FORCE }, { "image-policy", required_argument, NULL, ARG_IMAGE_POLICY }, { "noexec", required_argument, NULL, ARG_NOEXEC }, { "no-reload", no_argument, NULL, ARG_NO_RELOAD }, {} }; int c, r; assert(argc >= 0); assert(argv); while ((c = getopt_long(argc, argv, "h", options, NULL)) >= 0) switch (c) { case 'h': return verb_help(argc, argv, NULL); case ARG_VERSION: return version(); case ARG_NO_PAGER: arg_pager_flags |= PAGER_DISABLE; break; case ARG_NO_LEGEND: arg_legend = false; break; case ARG_ROOT: r = parse_path_argument(optarg, false, &arg_root); if (r < 0) return r; /* If --root= is provided, do not reload the service manager */ arg_no_reload = true; break; case ARG_JSON: r = parse_json_argument(optarg, &arg_json_format_flags); if (r <= 0) return r; break; case ARG_FORCE: arg_force = true; break; case ARG_IMAGE_POLICY: r = parse_image_policy_argument(optarg, &arg_image_policy); if (r < 0) return r; break; case ARG_NOEXEC: r = parse_boolean_argument("--noexec", optarg, NULL); if (r < 0) return r; arg_noexec = r; break; case ARG_NO_RELOAD: arg_no_reload = true; break; case '?': return -EINVAL; default: assert_not_reached(); } r = varlink_invocation(VARLINK_ALLOW_ACCEPT); if (r < 0) return log_error_errno(r, "Failed to check if invoked in Varlink mode: %m"); if (r > 0) arg_varlink = true; return 1; } static int sysext_main(int argc, char *argv[]) { static const Verb verbs[] = { { "status", VERB_ANY, 1, VERB_DEFAULT, verb_status }, { "merge", VERB_ANY, 1, 0, verb_merge }, { "unmerge", VERB_ANY, 1, 0, verb_unmerge }, { "refresh", VERB_ANY, 1, 0, verb_refresh }, { "list", VERB_ANY, 1, 0, verb_list }, { "help", VERB_ANY, 1, 0, verb_help }, {} }; return dispatch_verb(argc, argv, verbs, NULL); } static int run(int argc, char *argv[]) { int r; log_setup(); arg_image_class = invoked_as(argv, "systemd-confext") ? IMAGE_CONFEXT : IMAGE_SYSEXT; r = parse_argv(argc, argv); if (r <= 0) return r; /* For debugging purposes it might make sense to do this for other hierarchies than /usr/ and * /opt/, but let's make that a hacker/debugging feature, i.e. env var instead of cmdline * switch. */ r = parse_env_extension_hierarchies(&arg_hierarchies, image_class_info[arg_image_class].name_env); if (r < 0) return log_error_errno(r, "Failed to parse environment variable: %m"); if (arg_varlink) { _cleanup_(varlink_server_unrefp) VarlinkServer *varlink_server = NULL; /* Invocation as Varlink service */ r = varlink_server_new(&varlink_server, VARLINK_SERVER_ROOT_ONLY); if (r < 0) return log_error_errno(r, "Failed to allocate Varlink server: %m"); r = varlink_server_add_interface(varlink_server, &vl_interface_io_systemd_sysext); if (r < 0) return log_error_errno(r, "Failed to add Varlink interface: %m"); r = varlink_server_bind_method_many( varlink_server, "io.systemd.sysext.Merge", vl_method_merge, "io.systemd.sysext.Unmerge", vl_method_unmerge, "io.systemd.sysext.Refresh", vl_method_refresh, "io.systemd.sysext.List", vl_method_list); if (r < 0) return log_error_errno(r, "Failed to bind Varlink methods: %m"); r = varlink_server_loop_auto(varlink_server); if (r == -EPERM) return log_error_errno(r, "Invoked by unprivileged Varlink peer, refusing."); if (r < 0) return log_error_errno(r, "Failed to run Varlink event loop: %m"); return EXIT_SUCCESS; } return sysext_main(argc, argv); } DEFINE_MAIN_FUNCTION(run);