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Diffstat (limited to 'src/grp-login/pam_systemd/pam_systemd.c')
-rw-r--r--src/grp-login/pam_systemd/pam_systemd.c553
1 files changed, 553 insertions, 0 deletions
diff --git a/src/grp-login/pam_systemd/pam_systemd.c b/src/grp-login/pam_systemd/pam_systemd.c
new file mode 100644
index 0000000000..fe1a2266b7
--- /dev/null
+++ b/src/grp-login/pam_systemd/pam_systemd.c
@@ -0,0 +1,553 @@
+/***
+ 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 Lesser General Public License as published by
+ the Free Software Foundation; either version 2.1 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
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
+
+#include <endian.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <security/_pam_macros.h>
+#include <security/pam_ext.h>
+#include <security/pam_misc.h>
+#include <security/pam_modules.h>
+#include <security/pam_modutil.h>
+#include <sys/file.h>
+
+#include "sd-bus/bus-common-errors.h"
+#include "sd-bus/bus-error.h"
+#include "sd-bus/bus-util.h"
+#include "systemd-basic/alloc-util.h"
+#include "systemd-basic/audit-util.h"
+#include "systemd-basic/def.h"
+#include "systemd-basic/fd-util.h"
+#include "systemd-basic/fileio.h"
+#include "systemd-basic/formats-util.h"
+#include "systemd-basic/hostname-util.h"
+#include "systemd-basic/login-util.h"
+#include "systemd-basic/macro.h"
+#include "systemd-basic/parse-util.h"
+#include "systemd-basic/socket-util.h"
+#include "systemd-basic/strv.h"
+#include "systemd-basic/terminal-util.h"
+#include "systemd-basic/util.h"
+
+static int parse_argv(
+ pam_handle_t *handle,
+ int argc, const char **argv,
+ const char **class,
+ const char **type,
+ bool *debug) {
+
+ unsigned i;
+
+ assert(argc >= 0);
+ assert(argc == 0 || argv);
+
+ for (i = 0; i < (unsigned) argc; i++) {
+ if (startswith(argv[i], "class=")) {
+ if (class)
+ *class = argv[i] + 6;
+
+ } else if (startswith(argv[i], "type=")) {
+ if (type)
+ *type = argv[i] + 5;
+
+ } else if (streq(argv[i], "debug")) {
+ if (debug)
+ *debug = true;
+
+ } else if (startswith(argv[i], "debug=")) {
+ int k;
+
+ k = parse_boolean(argv[i] + 6);
+ if (k < 0)
+ pam_syslog(handle, LOG_WARNING, "Failed to parse debug= argument, ignoring.");
+ else if (debug)
+ *debug = k;
+
+ } else
+ pam_syslog(handle, LOG_WARNING, "Unknown parameter '%s', ignoring", argv[i]);
+ }
+
+ return 0;
+}
+
+static int get_user_data(
+ pam_handle_t *handle,
+ const char **ret_username,
+ struct passwd **ret_pw) {
+
+ const char *username = NULL;
+ struct passwd *pw = NULL;
+ int r;
+
+ assert(handle);
+ assert(ret_username);
+ assert(ret_pw);
+
+ r = pam_get_user(handle, &username, NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user name.");
+ return r;
+ }
+
+ if (isempty(username)) {
+ pam_syslog(handle, LOG_ERR, "User name not valid.");
+ return PAM_AUTH_ERR;
+ }
+
+ pw = pam_modutil_getpwnam(handle, username);
+ if (!pw) {
+ 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 get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
+ union sockaddr_union sa = {
+ .un.sun_family = AF_UNIX,
+ };
+ _cleanup_free_ char *p = NULL, *tty = NULL;
+ _cleanup_close_ int fd = -1;
+ struct ucred ucred;
+ int v, r;
+
+ assert(display);
+ assert(vtnr);
+
+ /* We deduce the X11 socket from the display name, then use
+ * SO_PEERCRED to determine the X11 server process, ask for
+ * the controlling tty of that and if it's a VC then we know
+ * the seat and the virtual terminal. Sounds ugly, is only
+ * semi-ugly. */
+
+ r = socket_from_display(display, &p);
+ if (r < 0)
+ return r;
+ strncpy(sa.un.sun_path, p, sizeof(sa.un.sun_path)-1);
+
+ fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+ if (fd < 0)
+ return -errno;
+
+ if (connect(fd, &sa.sa, SOCKADDR_UN_LEN(sa.un)) < 0)
+ return -errno;
+
+ r = getpeercred(fd, &ucred);
+ if (r < 0)
+ return r;
+
+ r = get_ctty(ucred.pid, NULL, &tty);
+ if (r < 0)
+ return r;
+
+ v = vtnr_from_tty(tty);
+ if (v < 0)
+ return v;
+ else if (v == 0)
+ return -ENOENT;
+
+ if (seat)
+ *seat = "seat0";
+ *vtnr = (uint32_t) v;
+
+ return 0;
+}
+
+static int export_legacy_dbus_address(
+ pam_handle_t *handle,
+ uid_t uid,
+ const char *runtime) {
+
+ _cleanup_free_ char *s = NULL;
+ int r = PAM_BUF_ERR;
+
+ /* FIXME: We *really* should move the access() check into the
+ * daemons that spawn dbus-daemon, instead of forcing
+ * DBUS_SESSION_BUS_ADDRESS= here. */
+
+ s = strjoin(runtime, "/bus", NULL);
+ if (!s)
+ goto error;
+
+ if (access(s, F_OK) < 0)
+ return PAM_SUCCESS;
+
+ s = mfree(s);
+ if (asprintf(&s, UNIX_USER_BUS_ADDRESS_FMT, runtime) < 0)
+ goto error;
+
+ r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", s, 0);
+ if (r != PAM_SUCCESS)
+ goto error;
+
+ return PAM_SUCCESS;
+
+error:
+ pam_syslog(handle, LOG_ERR, "Failed to set bus variable.");
+ return r;
+}
+
+_public_ PAM_EXTERN int pam_sm_open_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+ const char
+ *username, *id, *object_path, *runtime_path,
+ *service = NULL,
+ *tty = NULL, *display = NULL,
+ *remote_user = NULL, *remote_host = NULL,
+ *seat = NULL,
+ *type = NULL, *class = NULL,
+ *class_pam = NULL, *type_pam = NULL, *cvtnr = NULL, *desktop = NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ int session_fd = -1, existing, r;
+ bool debug = false, remote;
+ struct passwd *pw;
+ uint32_t vtnr = 0;
+ uid_t original_uid;
+
+ assert(handle);
+
+ /* Make this a NOP on non-logind systems */
+ if (!logind_running())
+ return PAM_SUCCESS;
+
+ if (parse_argv(handle,
+ argc, argv,
+ &class_pam,
+ &type_pam,
+ &debug) < 0)
+ return PAM_SESSION_ERR;
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "pam-systemd initializing");
+
+ r = get_user_data(handle, &username, &pw);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to get user data.");
+ return r;
+ }
+
+ /* Make sure we don't enter a loop by talking to
+ * systemd-logind when it is actually waiting for the
+ * background to finish start-up. If the service is
+ * "systemd-user" we simply set XDG_RUNTIME_DIR and
+ * leave. */
+
+ pam_get_item(handle, PAM_SERVICE, (const void**) &service);
+ if (streq_ptr(service, "systemd-user")) {
+ _cleanup_free_ char *rt = NULL;
+
+ if (asprintf(&rt, "/run/user/"UID_FMT, pw->pw_uid) < 0)
+ return PAM_BUF_ERR;
+
+ r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ return r;
+ }
+
+ r = export_legacy_dbus_address(handle, pw->pw_uid, rt);
+ if (r != PAM_SUCCESS)
+ return r;
+
+ return PAM_SUCCESS;
+ }
+
+ /* Otherwise, we ask logind to create a session for us */
+
+ pam_get_item(handle, PAM_XDISPLAY, (const void**) &display);
+ pam_get_item(handle, PAM_TTY, (const void**) &tty);
+ pam_get_item(handle, PAM_RUSER, (const void**) &remote_user);
+ pam_get_item(handle, PAM_RHOST, (const void**) &remote_host);
+
+ seat = pam_getenv(handle, "XDG_SEAT");
+ if (isempty(seat))
+ seat = getenv("XDG_SEAT");
+
+ cvtnr = pam_getenv(handle, "XDG_VTNR");
+ if (isempty(cvtnr))
+ cvtnr = getenv("XDG_VTNR");
+
+ type = pam_getenv(handle, "XDG_SESSION_TYPE");
+ if (isempty(type))
+ type = getenv("XDG_SESSION_TYPE");
+ if (isempty(type))
+ type = type_pam;
+
+ class = pam_getenv(handle, "XDG_SESSION_CLASS");
+ if (isempty(class))
+ class = getenv("XDG_SESSION_CLASS");
+ if (isempty(class))
+ class = class_pam;
+
+ desktop = pam_getenv(handle, "XDG_SESSION_DESKTOP");
+ if (isempty(desktop))
+ desktop = getenv("XDG_SESSION_DESKTOP");
+
+ tty = strempty(tty);
+
+ if (strchr(tty, ':')) {
+ /* A tty with a colon is usually an X11 display,
+ * placed there to show up in utmp. We rearrange
+ * things and don't pretend that an X display was a
+ * tty. */
+
+ if (isempty(display))
+ display = tty;
+ tty = NULL;
+ } else if (streq(tty, "cron")) {
+ /* cron has been setting PAM_TTY to "cron" for a very
+ * long time and it probably shouldn't stop doing that
+ * for compatibility reasons. */
+ type = "unspecified";
+ class = "background";
+ tty = NULL;
+ } else if (streq(tty, "ssh")) {
+ /* ssh has been setting PAM_TTY to "ssh" for a very
+ * long time and probably shouldn't stop doing that
+ * for compatibility reasons. */
+ type ="tty";
+ class = "user";
+ tty = NULL;
+ }
+
+ /* If this fails vtnr will be 0, that's intended */
+ if (!isempty(cvtnr))
+ (void) safe_atou32(cvtnr, &vtnr);
+
+ if (!isempty(display) && !vtnr) {
+ if (isempty(seat))
+ get_seat_from_display(display, &seat, &vtnr);
+ else if (streq(seat, "seat0"))
+ get_seat_from_display(display, NULL, &vtnr);
+ }
+
+ if (seat && !streq(seat, "seat0") && vtnr != 0) {
+ pam_syslog(handle, LOG_DEBUG, "Ignoring vtnr %"PRIu32" for %s which is not seat0", vtnr, seat);
+ vtnr = 0;
+ }
+
+ if (isempty(type))
+ type = !isempty(display) ? "x11" :
+ !isempty(tty) ? "tty" : "unspecified";
+
+ if (isempty(class))
+ class = streq(type, "unspecified") ? "background" : "user";
+
+ remote = !isempty(remote_host) && !is_localhost(remote_host);
+
+ /* Talk to logind over the message bus */
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
+ "uid="UID_FMT" pid="PID_FMT" service=%s type=%s class=%s desktop=%s seat=%s vtnr=%"PRIu32" tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
+ pw->pw_uid, getpid(),
+ strempty(service),
+ type, class, strempty(desktop),
+ strempty(seat), vtnr, strempty(tty), strempty(display),
+ yes_no(remote), strempty(remote_user), strempty(remote_host));
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.login1",
+ "/org/freedesktop/login1",
+ "org.freedesktop.login1.Manager",
+ "CreateSession",
+ &error,
+ &reply,
+ "uusssssussbssa(sv)",
+ (uint32_t) pw->pw_uid,
+ (uint32_t) getpid(),
+ service,
+ type,
+ class,
+ desktop,
+ seat,
+ vtnr,
+ tty,
+ display,
+ remote,
+ remote_user,
+ remote_host,
+ 0);
+ if (r < 0) {
+ if (sd_bus_error_has_name(&error, BUS_ERROR_SESSION_BUSY)) {
+ pam_syslog(handle, LOG_DEBUG, "Cannot create session: %s", bus_error_message(&error, r));
+ return PAM_SUCCESS;
+ } else {
+ pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error, r));
+ return PAM_SYSTEM_ERR;
+ }
+ }
+
+ r = sd_bus_message_read(reply,
+ "soshusub",
+ &id,
+ &object_path,
+ &runtime_path,
+ &session_fd,
+ &original_uid,
+ &seat,
+ &vtnr,
+ &existing);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ if (debug)
+ pam_syslog(handle, LOG_DEBUG, "Reply from logind: "
+ "id=%s object_path=%s runtime_path=%s session_fd=%d seat=%s vtnr=%u original_uid=%u",
+ id, object_path, runtime_path, session_fd, seat, vtnr, original_uid);
+
+ r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set session id.");
+ return r;
+ }
+
+ if (original_uid == pw->pw_uid) {
+ /* Don't set $XDG_RUNTIME_DIR if the user we now
+ * authenticated for does not match the original user
+ * of the session. We do this in order not to result
+ * in privileged apps clobbering the runtime directory
+ * unnecessarily. */
+
+ r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", runtime_path, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+ return r;
+ }
+
+ r = export_legacy_dbus_address(handle, pw->pw_uid, runtime_path);
+ if (r != PAM_SUCCESS)
+ return r;
+ }
+
+ if (!isempty(seat)) {
+ r = pam_misc_setenv(handle, "XDG_SEAT", seat, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set seat.");
+ return r;
+ }
+ }
+
+ if (vtnr > 0) {
+ char buf[DECIMAL_STR_MAX(vtnr)];
+ sprintf(buf, "%u", vtnr);
+
+ r = pam_misc_setenv(handle, "XDG_VTNR", buf, 0);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to set virtual terminal number.");
+ return r;
+ }
+ }
+
+ r = pam_set_data(handle, "systemd.existing", INT_TO_PTR(!!existing), NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to install existing flag.");
+ return r;
+ }
+
+ if (session_fd >= 0) {
+ session_fd = fcntl(session_fd, F_DUPFD_CLOEXEC, 3);
+ if (session_fd < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to dup session fd: %m");
+ return PAM_SESSION_ERR;
+ }
+
+ r = pam_set_data(handle, "systemd.session-fd", FD_TO_PTR(session_fd), NULL);
+ if (r != PAM_SUCCESS) {
+ pam_syslog(handle, LOG_ERR, "Failed to install session fd.");
+ safe_close(session_fd);
+ return r;
+ }
+ }
+
+ return PAM_SUCCESS;
+}
+
+_public_ PAM_EXTERN int pam_sm_close_session(
+ pam_handle_t *handle,
+ int flags,
+ int argc, const char **argv) {
+
+ _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+ _cleanup_(sd_bus_flush_close_unrefp) sd_bus *bus = NULL;
+ const void *existing = NULL;
+ const char *id;
+ int r;
+
+ assert(handle);
+
+ /* Only release session if it wasn't pre-existing when we
+ * tried to create it */
+ pam_get_data(handle, "systemd.existing", &existing);
+
+ id = pam_getenv(handle, "XDG_SESSION_ID");
+ if (id && !existing) {
+
+ /* Before we go and close the FIFO we need to tell
+ * logind that this is a clean session shutdown, so
+ * that it doesn't just go and slaughter us
+ * immediately after closing the fd */
+
+ r = sd_bus_open_system(&bus);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", strerror(-r));
+ return PAM_SESSION_ERR;
+ }
+
+ r = sd_bus_call_method(bus,
+ "org.freedesktop.login1",
+ "/org/freedesktop/login1",
+ "org.freedesktop.login1.Manager",
+ "ReleaseSession",
+ &error,
+ NULL,
+ "s",
+ id);
+ if (r < 0) {
+ pam_syslog(handle, LOG_ERR, "Failed to release session: %s", bus_error_message(&error, r));
+ return PAM_SESSION_ERR;
+ }
+ }
+
+ /* Note that we are knowingly leaking the FIFO fd here. This
+ * way, logind can watch us die. If we closed it here it would
+ * not have any clue when that is completed. Given that one
+ * cannot really have multiple PAM sessions open from the same
+ * process this means we will leak one FD at max. */
+
+ return PAM_SUCCESS;
+}
generated by cgit v1.2.3-54-g00ecf (git 2.45.2) at 2024-11-19 00:19:54 +0000