diff options
Diffstat (limited to '')
-rw-r--r-- | src/login/user-runtime-dir.c | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/src/login/user-runtime-dir.c b/src/login/user-runtime-dir.c new file mode 100644 index 0000000..eb66e18 --- /dev/null +++ b/src/login/user-runtime-dir.c @@ -0,0 +1,198 @@ +/* SPDX-License-Identifier: LGPL-2.1+ */ + +#include <stdint.h> +#include <sys/mount.h> + +#include "sd-bus.h" + +#include "bus-error.h" +#include "fs-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); |