-/*-*- Mode: C; c-basic-offset: 8 -*-*/
+/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
#include <fcntl.h>
#include <sys/file.h>
#include <pwd.h>
+#include <endian.h>
#include <security/pam_modules.h>
#include <security/_pam_macros.h>
#include <security/pam_ext.h>
#include <security/pam_misc.h>
-#include <libcgroup.h>
-
#include "util.h"
#include "cgroup-util.h"
#include "macro.h"
if ((fd = open(fn, O_RDWR|O_CLOEXEC|O_NOCTTY|O_NOFOLLOW|O_CREAT, 0600)) < 0)
return -errno;
+ /* The BSD socket semantics are a lot nicer than those of
+ * POSIX locks. Which is why we use flock() here. BSD locking
+ * does not work across NFS which however is not needed here
+ * as the filesystems in question should be local, and only
+ * locally accessible, and most likely even tmpfs. */
+
if (flock(fd, LOCK_EX) < 0)
return -errno;
return fd;
}
-static uint32_t combine32(unsigned long long u) {
- uint32_t r = 0;
- unsigned i;
+enum {
+ SESSION_ID_AUDIT = 'a',
+ SESSION_ID_COUNTER = 'c',
+ SESSION_ID_RANDOM = 'r'
+};
- for (i = 0; i < sizeof(u)/4; i ++)
- r ^= (uint32_t) ((u >> (i*32)) & 0xFFFFFFFFULL);
+static uint64_t get_session_id(int *mode) {
+ char *s;
+ int fd;
- return r;
-}
+ assert(mode);
-static char *generate_session_cookie(void) {
- char *machine;
- char *cookie;
- unsigned long long r;
- usec_t u;
- int k;
+ /* First attempt: let's use the session ID of the audit
+ * system, if it is available. */
+ if (read_one_line_file("/proc/self/sessionid", &s) >= 0) {
+ uint32_t u;
+ int r;
- if (getmachineid_malloc(&machine) < 0)
- if (!(machine = gethostname_malloc()))
- return NULL;
+ r = safe_atou32(s, &u);
+ free(s);
- r = random_ull();
- u = now(CLOCK_REALTIME);
+ if (r >= 0 && u != (uint32_t) -1) {
+ *mode = SESSION_ID_AUDIT;
+ return (uint64_t) u;
+ }
+ }
- k = asprintf(&cookie, "%s-%lu-%lu",
- machine,
- (unsigned long) combine32(r),
- (unsigned long) combine32((unsigned long long) u));
- free(machine);
+ /* Second attempt, use our own counter. */
+ if ((fd = open_file_and_lock(RUNTIME_DIR "/user/.pam-systemd-session")) >= 0) {
+ uint64_t counter;
+ ssize_t r;
- return k < 0 ? NULL : cookie;
-}
+ /* We do a bit of endianess swapping here, just to be
+ * sure. /var should be machine specific anyway, and
+ * /var/run even mounted from tmpfs, so this
+ * byteswapping should really not be necessary. But
+ * then again, you never know, so let's avoid any
+ * risk. */
+
+ if (loop_read(fd, &counter, sizeof(counter), false) != sizeof(counter))
+ counter = 1;
+ else
+ counter = le64toh(counter) + 1;
+
+ if (lseek(fd, 0, SEEK_SET) == 0) {
+ uint64_t swapped = htole64(counter);
+
+ r = loop_write(fd, &swapped, sizeof(swapped), false);
+
+ if (r != sizeof(swapped))
+ r = -EIO;
+ } else
+ r = -errno;
+ close_nointr_nofail(fd);
+
+ if (r >= 0) {
+ *mode = SESSION_ID_COUNTER;
+ return counter;
+ }
+ }
+
+ *mode = SESSION_ID_RANDOM;
+
+ /* Last attempt, pick a random value */
+ return (uint64_t) random_ull();
+}
static int get_user_data(
pam_handle_t *handle,
const char **ret_username,
return PAM_SUCCESS;
}
-static int create_user_group(pam_handle_t *handle, const char *group, struct passwd *pw, bool attach) {
+static int create_user_group(pam_handle_t *handle, const char *group, struct passwd *pw, bool attach, bool remember) {
int r;
assert(handle);
assert(group);
if (attach)
- r = cg_create_and_attach("name=systemd", group, 0);
+ r = cg_create_and_attach(SYSTEMD_CGROUP_CONTROLLER, group, 0);
else
- r = cg_create("name=systemd", group);
+ r = cg_create(SYSTEMD_CGROUP_CONTROLLER, 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) {
+ if (r > 0 && remember) {
+ /* Remember that it was us who created this group, and
+ * that hence we need to remove it too. This is a
+ * protection against removing the cgroup when run
+ * recursively. */
+ if ((r = pam_set_data(handle, "systemd.created", INT_TO_PTR(1), NULL)) != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to install created variable.");
+ return r;
+ }
+ }
+
+ if ((r = cg_set_task_access(SYSTEMD_CGROUP_CONTROLLER, group, 0755, pw->pw_uid, pw->pw_gid)) < 0 ||
+ (r = cg_set_group_access(SYSTEMD_CGROUP_CONTROLLER, 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;
}
assert(handle);
- pam_syslog(handle, LOG_INFO, "pam-systemd initializing");
+ /* pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing"); */
if (parse_argv(handle, argc, argv, &create_session, NULL, NULL) < 0)
return PAM_SESSION_ERR;
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;
buf = NULL;
if (create_session) {
- const char *cookie;
+ const char *id;
/* Reuse or create XDG session ID */
- if (!(cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
- if (!(buf = generate_session_cookie())) {
+ if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
+ int mode;
+
+ if (asprintf(&buf, "%llux", (unsigned long long) get_session_id(&mode)) < 0) {
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.");
+ /* To avoid id clashes we add the session id
+ * source to our session ids. Note that the
+ * session id source might change during
+ * runtime, because a filesystem became
+ * writable or the system reconfigured. */
+ buf[strlen(buf)-1] =
+ mode != SESSION_ID_AUDIT ? (char) mode : 0;
+
+ if ((r = pam_misc_setenv(handle, "XDG_SESSION_ID", buf, 0)) != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set session id.");
goto finish;
}
- if (!(cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
- pam_syslog(handle, LOG_ERR, "Failed to get cookie.");
+ if (!(id = pam_getenv(handle, "XDG_SESSION_ID"))) {
+ pam_syslog(handle, LOG_ERR, "Failed to get session id.");
r = PAM_SESSION_ERR;
goto finish;
}
}
- r = asprintf(&buf, "/user/%s/%s", username, cookie);
+ r = asprintf(&buf, "/user/%s/%s", username, id);
} else
- r = asprintf(&buf, "/user/%s/no-session", username);
+ r = asprintf(&buf, "/user/%s/master", username);
if (r < 0) {
r = PAM_BUF_ERR;
goto finish;
}
- if ((r = create_user_group(handle, buf, pw, true)) != PAM_SUCCESS)
+ pam_syslog(handle, LOG_INFO, "Moving new user session for %s into control group %s.", username, buf);
+
+ if ((r = create_user_group(handle, buf, pw, true, true)) != PAM_SUCCESS)
goto finish;
r = PAM_SUCCESS;
}
static int session_remains(pam_handle_t *handle, const char *user_path) {
- struct cgroup_file_info info;
- int level = 0, r;
- void *iterator = NULL;
+ int r;
bool remains = false;
+ DIR *d;
+ char *subgroup;
- 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;
+ if ((r = cg_enumerate_subgroups(SYSTEMD_CGROUP_CONTROLLER, user_path, &d)) < 0)
+ return r;
- remains = true;
- break;
+ while ((r = cg_read_subgroup(d, &subgroup)) > 0) {
- next:
+ remains = !streq(subgroup, "master");
+ free(subgroup);
- r = cgroup_walk_tree_next(0, &iterator, &info, level);
+ if (remains)
+ break;
}
+ closedir(d);
- 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);
+ if (r < 0)
+ return r;
- return r;
+ return !!remains;
}
_public_ PAM_EXTERN int pam_sm_close_session(
bool kill_user = false;
int lock_fd = -1, r;
char *session_path = NULL, *nosession_path = NULL, *user_path = NULL;
- const char *cookie;
+ const char *id;
struct passwd *pw;
+ const void *created = NULL;
assert(handle);
goto finish;
}
+ /* We are probably still in some session/user dir. Move ourselves out of the way as first step */
+ if ((r = cg_attach(SYSTEMD_CGROUP_CONTROLLER, "/user", 0)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to move us away: %s", strerror(-r));
+
if (asprintf(&user_path, "/user/%s", username) < 0) {
r = PAM_BUF_ERR;
goto finish;
}
- if ((cookie = pam_getenv(handle, "XDG_SESSION_COOKIE"))) {
+ pam_get_data(handle, "systemd.created", &created);
+
+ if ((id = pam_getenv(handle, "XDG_SESSION_ID")) && created) {
- if (asprintf(&session_path, "/user/%s/%s", username, cookie) < 0 ||
- asprintf(&nosession_path, "/user/%s/no-session", username) < 0) {
+ if (asprintf(&session_path, "/user/%s/%s", username, id) < 0 ||
+ asprintf(&nosession_path, "/user/%s/master", username) < 0) {
r = PAM_BUF_ERR;
goto finish;
}
if (kill_session) {
- pam_syslog(handle, LOG_INFO, "KILLING ENTER");
+ pam_syslog(handle, LOG_INFO, "Killing remaining processes of user session %s of %s.", id, username);
- /* Kill processes in session cgroup */
- if ((r = cg_kill_recursive_and_wait("name=systemd", session_path)) < 0)
+ /* Kill processes in session cgroup, and delete it */
+ if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, session_path, true)) < 0)
pam_syslog(handle, LOG_ERR, "Failed to kill session cgroup: %s", strerror(-r));
+ } else {
+ pam_syslog(handle, LOG_INFO, "Moving remaining processes of user session %s of %s into control group %s.", id, username, nosession_path);
- 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);
+ /* Migrate processes from session to user
+ * cgroup. First, try to create the user group
+ * in case it doesn't exist yet. Also, delete
+ * the session group. */
+ create_user_group(handle, nosession_path, pw, false, false);
- if ((r = cg_migrate_recursive("name=systemd", session_path, nosession_path, false)) < 0)
+ if ((r = cg_migrate_recursive(SYSTEMD_CGROUP_CONTROLLER, session_path, nosession_path, false, true)) < 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);
+ cg_trim(SYSTEMD_CGROUP_CONTROLLER, 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)
+ /* Kill user cgroup */
+ if ((r = cg_kill_recursive_and_wait(SYSTEMD_CGROUP_CONTROLLER, user_path, true)) < 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)
+ if ((r = cg_is_empty_recursive(SYSTEMD_CGROUP_CONTROLLER, 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)
+ /* Remove user cgroup */
+ if (r > 0) {
+ if ((r = cg_delete(SYSTEMD_CGROUP_CONTROLLER, user_path)) < 0)
+ pam_syslog(handle, LOG_ERR, "Failed to delete user cgroup: %s", strerror(-r));
+
+ /* If we managed to find somebody, don't cleanup the cgroup. */
+ } else 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));
}
+ /* pam_syslog(handle, LOG_DEBUG, "pam-systemd done"); */
+
r = PAM_SUCCESS;
finish:
~ianmdlvl / elogind.git / blobdiff