+/*-*- Mode: C; c-basic-offset: 8 -*-*/
+
+/***
+ 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 General Public License as published by
+ the Free Software Foundation; either version 2 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
+ General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <errno.h>
+#include <fcntl.h>
+#include <sys/file.h>
+#include <pwd.h>
+
+#include <security/pam_modules.h>
+#include <security/_pam_macros.h>
+#include <security/pam_modutil.h>
+#include <security/pam_ext.h>
+#include <security/pam_misc.h>
+
+#include <libcgroup.h>
+
+#include "util.h"
+#include "cgroup-util.h"
+#include "macro.h"
+#include "sd-daemon.h"
+
+static int parse_argv(pam_handle_t *handle,
+ int argc, const char **argv,
+ bool *create_session,
+ bool *kill_session,
+ bool *kill_user) {
+
+ unsigned i;
+
+ assert(argc >= 0);
+ assert(argc == 0 || argv);
+
+ for (i = 0; i < (unsigned) argc; i++) {
+ int k;
+
+ if (startswith(argv[i], "create-session=")) {
+ if ((k = parse_boolean(argv[i] + 15)) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to parse create-session= argument.");
+ return k;
+ }
+
+ if (create_session)
+ *create_session = k;
+ } else if (startswith(argv[i], "kill-session=")) {
+ if ((k = parse_boolean(argv[i] + 13)) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
+ return k;
+ }
+
+ if (kill_session)
+ *kill_session = k;
+
+ } else if (startswith(argv[i], "kill-user=")) {
+ if ((k = parse_boolean(argv[i] + 10)) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to parse kill-user= argument.");
+ return k;
+ }
+
+ if (kill_user)
+ *kill_user = k;
+ } else {
+ pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
+ return -EINVAL;
+ }
+ }
+
+ if (kill_session && *kill_session && kill_user)
+ *kill_user = true;
+
+ return 0;
+}
+
+static int open_file_and_lock(const char *fn) {
+ int fd;
+
+ assert(fn);
+
+ if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
+ return -errno;
+
+ if (flock(fd, LOCK_EX) < 0)
+ return -errno;
+
+ return fd;
+}
+
+static uint32_t combine32(unsigned long long u) {
+ uint32_t r = 0;
+ unsigned i;
+
+ for (i = 0; i < sizeof(u)/4; i ++)
+ r ^= (uint32_t) ((u >> (i*32)) & 0xFFFFFFFFULL);
+
+ return r;
+}
+
+static char *generate_session_cookie(void) {
+ char *machine;
+ char *cookie;
+ unsigned long long r;
+ usec_t u;
+ int k;
+
+ if (getmachineid_malloc(&machine) < 0)
+ if (!(machine = gethostname_malloc()))
+ return NULL;
+
+ r = random_ull();
+ u = now(CLOCK_REALTIME);
+
+ k = asprintf(&cookie, "%s-%lu-%lu",
+ machine,
+ (unsigned long) combine32(r),
+ (unsigned long) combine32((unsigned long long) u));
+ free(machine);
+
+ return k < 0 ? NULL : cookie;
+}
+
+static int get_user_data(
+ pam_handle_t *handle,
+ const char **ret_username,
+ struct passwd **ret_pw) {
+
+ const char *username;
+ struct passwd *pw;
+ int r;
+
+ assert(handle);
+ assert(ret_username);
+ assert(ret_pw);
+
+ if ((r = pam_get_user(handle, &username, NULL)) != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user name.");
+ return r;
+ }
+
+ if (!username || !*username) {
+ pam_syslog(handle, LOG_ERR, "User name not valid.");
+ return PAM_AUTH_ERR;
+ }
+
+ if (!(pw = pam_modutil_getpwnam(handle, username))) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user data.");
+ return PAM_USER_UNKNOWN;
+ }
+
+ *ret_pw = pw;
+ *ret_username = username;
+
+ return PAM_SUCCESS;
+}
+
+static int create_user_group(pam_handle_t *handle, const char *group, struct passwd *pw, bool attach) {
+ int r;
+
+ assert(handle);
+ assert(group);
+
+ if (attach)
+ r = cg_create_and_attach("name=systemd", group, 0);
+ else
+ r = cg_create("name=systemd", group);
+
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to create cgroup: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ if ((r = cg_set_task_access("name=systemd", group, 0755, pw->pw_uid, pw->pw_gid)) < 0 ||
+ (r = cg_set_group_access("name=systemd", group, 0755, pw->pw_uid, pw->pw_gid)) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to change access modes: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ return PAM_SUCCESS;
+}
+
+_public_ PAM_EXTERN int pam_sm_open_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ const char *username = NULL;
+ struct passwd *pw;
+ int r;
+ char *buf = NULL;
+ int lock_fd = -1;
+ bool create_session = true;
+
+ assert(handle);
+
+ pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
+
+ if (parse_argv(handle, argc, argv, &create_session, NULL, NULL) < 0)
+ return PAM_SESSION_ERR;
+
+ /* Make this a NOP on non-systemd systems */
+ if (sd_booted() <= 0)
+ return PAM_SUCCESS;
+
+ if ((r = cgroup_init()) != 0) {
+ pam_syslog(handle, LOG_ERR, "libcgroup initialization failed: %s", cgroup_strerror(r));
+ r = PAM_SESSION_ERR;
+ goto finish;
+ }
+
+ if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
+ goto finish;
+
+ if (safe_mkdir(RUNTIME_DIR "/user", 0755, 0, 0) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to create runtime directory: %m");
+ r = PAM_SYSTEM_ERR;
+ goto finish;
+ }
+
+ if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
+ r = PAM_SYSTEM_ERR;
+ goto finish;
+ }
+
+ /* Create /var/run/$USER */
+ free(buf);
+ if (asprintf(&buf, RUNTIME_DIR "/user/%s", username) < 0) {
+ r = PAM_BUF_ERR;
+ goto finish;
+ }
+
+ if (safe_mkdir(buf, 0700, pw->pw_uid, pw->pw_gid) < 0) {
+ pam_syslog(handle, LOG_WARNING, "Failed to create runtime directory: %m");
+ r = PAM_SYSTEM_ERR;
+ goto finish;
+ } else if ((r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", buf, 0)) != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ goto finish;
+ }
+
+ free(buf);
+ buf = NULL;
+
+ if (create_session) {
+ const char *cookie;
+
+ /* Reuse or create XDG session ID */
+ if (!(cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
+ if (!(buf = generate_session_cookie())) {
+ r = PAM_BUF_ERR;
+ goto finish;
+ }
+
+ if ((r = pam_misc_setenv(handle, "XDG_SESSION_COOKIE", buf, 0)) != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set cookie.");
+ goto finish;
+ }
+
+ if (!(cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
+ pam_syslog(handle, LOG_ERR, "Failed to get cookie.");
+ r = PAM_SESSION_ERR;
+ goto finish;
+ }
+ }
+
+ r = asprintf(&buf, "/user/%s/%s", username, cookie);
+ } else
+ r = asprintf(&buf, "/user/%s/no-session", username);
+
+ if (r < 0) {
+ r = PAM_BUF_ERR;
+ goto finish;
+ }
+
+ if ((r = create_user_group(handle, buf, pw, true)) != PAM_SUCCESS)
+ goto finish;
+
+ r = PAM_SUCCESS;
+
+finish:
+ free(buf);
+
+ if (lock_fd >= 0)
+ close_nointr_nofail(lock_fd);
+
+ return r;
+}
+
+static int session_remains(pam_handle_t *handle, const char *user_path) {
+ struct cgroup_file_info info;
+ int level = 0, r;
+ void *iterator = NULL;
+ bool remains = false;
+
+ zero(info);
+
+ r = cgroup_walk_tree_begin("name=systemd", user_path, 0, &iterator, &info, &level);
+ while (r == 0) {
+
+ if (info.type != CGROUP_FILE_TYPE_DIR)
+ goto next;
+
+ if (streq(info.path, ""))
+ goto next;
+
+ if (streq(info.path, "no-session"))
+ goto next;
+
+ remains = true;
+ break;
+
+ next:
+
+ r = cgroup_walk_tree_next(0, &iterator, &info, level);
+ }
+
+
+ if (remains)
+ r = 1;
+ else if (r == 0 || r == ECGEOF)
+ r = 0;
+ else
+ r = cg_translate_error(r, errno);
+
+ assert_se(cgroup_walk_tree_end(&iterator) == 0);
+
+ return r;
+}
+
+_public_ PAM_EXTERN int pam_sm_close_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ const char *username = NULL;
+ bool kill_session = false;
+ bool kill_user = false;
+ int lock_fd = -1, r;
+ char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
+ const char *cookie;
+ struct passwd *pw;
+
+ assert(handle);
+
+ if (parse_argv(handle, argc, argv, NULL, &kill_session, &kill_user) < 0)
+ return PAM_SESSION_ERR;
+
+ /* Make this a NOP on non-systemd systems */
+ if (sd_booted() <= 0)
+ return PAM_SUCCESS;
+
+ if ((r = get_user_data(handle, &username, &pw)) != PAM_SUCCESS)
+ goto finish;
+
+ if ((lock_fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-lock")) < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to lock runtime directory: %m");
+ r = PAM_SYSTEM_ERR;
+ goto finish;
+ }
+
+ if (asprintf(&user_path, "/user/%s", username) < 0) {
+ r = PAM_BUF_ERR;
+ goto finish;
+ }
+
+ if ((cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
+
+ if (asprintf(&session_path, "/user/%s/%s", username, cookie) < 0 ||
+ asprintf(&nosession_path, "/user/%s/no-session", username) < 0) {
+ r = PAM_BUF_ERR;
+ goto finish;
+ }
+
+ if (kill_session) {
+ pam_syslog(handle, LOG_INFO, "KILLING ENTER");
+
+ /* Kill processes in session cgroup */
+ if ((r = cg_kill_recursive_and_wait("name=systemd", session_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
+
+ pam_syslog(handle, LOG_INFO, "KILLING EXIT");
+
+ } else {
+ /* Migrate processes from session to
+ * no-session cgroup. First, try to create the
+ * no-session group in case it doesn't exist
+ * yet. */
+ create_user_group(handle, nosession_path, pw, 0);
+
+ if ((r = cg_migrate_recursive("name=systemd", session_path, nosession_path, false)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to migrate session cgroup: %s", strerror(-r));
+ }
+
+ /* Delete session cgroup */
+ if (r < 0)
+ pam_syslog(handle, LOG_INFO, "Couldn't empty session cgroup, not deleting.");
+ else {
+ if ((r = cg_delete("name=systemd", session_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to delete session cgroup: %s", strerror(-r));
+ }
+ }
+
+ /* GC user tree */
+ cg_trim("name=systemd", user_path, false);
+
+ if ((r = session_remains(handle, user_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to determine whether a session remains: %s", strerror(-r));
+
+ /* Kill user processes not attached to any session */
+ if (kill_user && r == 0) {
+
+ /* Kill no-session cgroup */
+ if ((r = cg_kill_recursive_and_wait("name=systemd", user_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to kill user cgroup: %s", strerror(-r));
+ } else {
+
+ if ((r = cg_is_empty_recursive("name=systemd", user_path, true)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to check user cgroup: %s", strerror(-r));
+
+ /* If we managed to kill somebody, don't cleanup the cgroup. */
+ if (r == 0)
+ r = -EBUSY;
+ }
+
+ if (r >= 0) {
+ const char *runtime_dir;
+
+ /* Remove user cgroup */
+ if ((r = cg_delete("name=systemd", user_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
+
+ /* This will migrate us to the /user cgroup. */
+
+ if ((runtime_dir = pam_getenv(handle, "XDG_RUNTIME_DIR")))
+ if ((r = rm_rf(runtime_dir, false, true)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to remove runtime directory: %s", strerror(-r));
+ }
+
+ r = PAM_SUCCESS;
+
+finish:
+ if (lock_fd >= 0)
+ close_nointr_nofail(lock_fd);
+
+ free(session_path);
+ free(nosession_path);
+ free(user_path);
+
+ return r;
+}
~ianmdlvl / elogind.git / commitdiff