/* SPDX-License-Identifier: LGPL-2.1+ */ #include #include #include "sd-bus.h" #include "bus-error.h" #include "fs-util.h" #include "format-util.h" #include "label.h" #include "main-func.h" #include "mkdir.h" #include "mountpoint-util.h" #include "path-util.h" #include "rm-rf.h" #include "selinux-util.h" #include "smack-util.h" #include "stdio-util.h" #include "string-util.h" #include "strv.h" #include "user-util.h" static int acquire_runtime_dir_size(uint64_t *ret) { _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL; _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL; int r; r = sd_bus_default_system(&bus); if (r < 0) return log_error_errno(r, "Failed to connect to system bus: %m"); r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectorySize", &error, 't', ret); if (r < 0) return log_error_errno(r, "Failed to acquire runtime directory size: %s", bus_error_message(&error, r)); return 0; } static int user_mkdir_runtime_path( const char *runtime_path, uid_t uid, gid_t gid, uint64_t runtime_dir_size) { int r; assert(runtime_path); assert(path_is_absolute(runtime_path)); assert(uid_is_valid(uid)); assert(gid_is_valid(gid)); r = mkdir_safe_label("/run/user", 0755, 0, 0, MKDIR_WARN_MODE); if (r < 0) return log_error_errno(r, "Failed to create /run/user: %m"); if (path_is_mount_point(runtime_path, NULL, 0) >= 0) log_debug("%s is already a mount point", runtime_path); else { char options[sizeof("mode=0700,uid=,gid=,size=,smackfsroot=*") + DECIMAL_STR_MAX(uid_t) + DECIMAL_STR_MAX(gid_t) + DECIMAL_STR_MAX(uint64_t)]; xsprintf(options, "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 "%s", uid, gid, runtime_dir_size, mac_smack_use() ? ",smackfsroot=*" : ""); (void) mkdir_label(runtime_path, 0700); r = mount("tmpfs", runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, options); if (r < 0) { if (!IN_SET(errno, EPERM, EACCES)) { r = log_error_errno(errno, "Failed to mount per-user tmpfs directory %s: %m", runtime_path); goto fail; } log_debug_errno(errno, "Failed to mount per-user tmpfs directory %s.\n" "Assuming containerized execution, ignoring: %m", runtime_path); r = chmod_and_chown(runtime_path, 0700, uid, gid); if (r < 0) { log_error_errno(r, "Failed to change ownership and mode of \"%s\": %m", runtime_path); goto fail; } } r = label_fix(runtime_path, 0); if (r < 0) log_warning_errno(r, "Failed to fix label of \"%s\", ignoring: %m", runtime_path); } return 0; fail: /* Try to clean up, but ignore errors */ (void) rmdir(runtime_path); return r; } static int user_remove_runtime_path(const char *runtime_path) { int r; assert(runtime_path); assert(path_is_absolute(runtime_path)); r = rm_rf(runtime_path, 0); if (r < 0) log_debug_errno(r, "Failed to remove runtime directory %s (before unmounting), ignoring: %m", runtime_path); /* Ignore cases where the directory isn't mounted, as that's quite possible, if we lacked the permissions to * mount something */ r = umount2(runtime_path, MNT_DETACH); if (r < 0 && !IN_SET(errno, EINVAL, ENOENT)) log_debug_errno(errno, "Failed to unmount user runtime directory %s, ignoring: %m", runtime_path); r = rm_rf(runtime_path, REMOVE_ROOT); if (r < 0 && r != -ENOENT) return log_error_errno(r, "Failed to remove runtime directory %s (after unmounting): %m", runtime_path); return 0; } static int do_mount(const char *user) { char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)]; uint64_t runtime_dir_size; uid_t uid; gid_t gid; int r; r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0); if (r < 0) return log_error_errno(r, r == -ESRCH ? "No such user \"%s\"" : r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group" : "Failed to look up user \"%s\": %m", user); r = acquire_runtime_dir_size(&runtime_dir_size); if (r < 0) return r; xsprintf(runtime_path, "/run/user/" UID_FMT, uid); log_debug("Will mount %s owned by "UID_FMT":"GID_FMT, runtime_path, uid, gid); return user_mkdir_runtime_path(runtime_path, uid, gid, runtime_dir_size); } static int do_umount(const char *user) { char runtime_path[sizeof("/run/user") + DECIMAL_STR_MAX(uid_t)]; uid_t uid; int r; /* The user may be already removed. So, first try to parse the string by parse_uid(), * and if it fails, fallback to get_user_creds().*/ if (parse_uid(user, &uid) < 0) { r = get_user_creds(&user, &uid, NULL, NULL, NULL, 0); if (r < 0) return log_error_errno(r, r == -ESRCH ? "No such user \"%s\"" : r == -ENOMSG ? "UID \"%s\" is invalid or has an invalid main group" : "Failed to look up user \"%s\": %m", user); } xsprintf(runtime_path, "/run/user/" UID_FMT, uid); log_debug("Will remove %s", runtime_path); return user_remove_runtime_path(runtime_path); } static int run(int argc, char *argv[]) { int r; log_parse_environment(); log_open(); if (argc != 3) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "This program takes two arguments."); if (!STR_IN_SET(argv[1], "start", "stop")) return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "First argument must be either \"start\" or \"stop\"."); r = mac_selinux_init(); if (r < 0) return log_error_errno(r, "Could not initialize labelling: %m\n"); umask(0022); if (streq(argv[1], "start")) return do_mount(argv[2]); if (streq(argv[1], "stop")) return do_umount(argv[2]); assert_not_reached("Unknown verb!"); } DEFINE_MAIN_FUNCTION(run);