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-rw-r--r--src/login/user-runtime-dir.c213
1 files changed, 213 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..9b5bdcc
--- /dev/null
+++ b/src/login/user-runtime-dir.c
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <stdint.h>
+#include <sys/mount.h>
+
+#include "sd-bus.h"
+
+#include "bus-error.h"
+#include "dev-setup.h"
+#include "format-util.h"
+#include "fs-util.h"
+#include "label.h"
+#include "limits-util.h"
+#include "main-func.h"
+#include "mkdir.h"
+#include "mount-util.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_properties(uint64_t *size, uint64_t *inodes) {
+ _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', size);
+ if (r < 0) {
+ log_warning_errno(r, "Failed to acquire runtime directory size, ignoring: %s", bus_error_message(&error, r));
+ *size = physical_memory_scale(10U, 100U); /* 10% */
+ }
+
+ r = sd_bus_get_property_trivial(bus, "org.freedesktop.login1", "/org/freedesktop/login1", "org.freedesktop.login1.Manager", "RuntimeDirectoryInodesMax", &error, 't', inodes);
+ if (r < 0) {
+ log_warning_errno(r, "Failed to acquire number of inodes for runtime directory, ignoring: %s", bus_error_message(&error, r));
+ *inodes = DIV_ROUND_UP(*size, 4096);
+ }
+
+ return 0;
+}
+
+static int user_mkdir_runtime_path(
+ const char *runtime_path,
+ uid_t uid,
+ gid_t gid,
+ uint64_t runtime_dir_size,
+ uint64_t runtime_dir_inodes) {
+
+ 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=,nr_inodes=,smackfsroot=*")
+ + DECIMAL_STR_MAX(uid_t)
+ + DECIMAL_STR_MAX(gid_t)
+ + DECIMAL_STR_MAX(uint64_t)
+ + DECIMAL_STR_MAX(uint64_t)];
+
+ xsprintf(options,
+ "mode=0700,uid=" UID_FMT ",gid=" GID_FMT ",size=%" PRIu64 ",nr_inodes=%" PRIu64 "%s",
+ uid, gid, runtime_dir_size, runtime_dir_inodes,
+ mac_smack_use() ? ",smackfsroot=*" : "");
+
+ (void) mkdir_label(runtime_path, 0700);
+
+ r = mount_nofollow_verbose(LOG_DEBUG, "tmpfs", runtime_path, "tmpfs", MS_NODEV|MS_NOSUID, options);
+ if (r < 0) {
+ if (!ERRNO_IS_PRIVILEGE(r)) {
+ log_error_errno(r, "Failed to mount per-user tmpfs directory %s: %m", runtime_path);
+ goto fail;
+ }
+
+ log_debug_errno(r,
+ "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, runtime_dir_inodes;
+ 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_properties(&runtime_dir_size, &runtime_dir_inodes);
+ 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, runtime_dir_inodes);
+}
+
+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, fall back 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\".");
+
+ umask(0022);
+
+ r = mac_selinux_init();
+ if (r < 0)
+ return r;
+
+ 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);
generated by cgit v1.2.3 (git 2.39.1) at 2024-07-01 22:17:51 +0000