| /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ |
| |
| /*** |
| 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 <errno.h> |
| #include <fcntl.h> |
| #include <sys/file.h> |
| #include <pwd.h> |
| #include <endian.h> |
| #include <sys/capability.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 "util.h" |
| #include "audit.h" |
| #include "macro.h" |
| #include "strv.h" |
| #include "bus-util.h" |
| #include "def.h" |
| #include "socket-util.h" |
| #include "fileio.h" |
| #include "bus-error.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, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 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) { |
| |
| #ifdef ENABLE_KDBUS |
| _cleanup_free_ char *s = NULL; |
| int r; |
| |
| /* skip export if kdbus is not active */ |
| if (access("/sys/fs/kdbus", F_OK) < 0) |
| return PAM_SUCCESS; |
| |
| if (asprintf(&s, KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT, uid, runtime) < 0) { |
| pam_syslog(handle, LOG_ERR, "Failed to set bus variable."); |
| return PAM_BUF_ERR; |
| } |
| |
| r = pam_misc_setenv(handle, "DBUS_SESSION_BUS_ADDRESS", s, 0); |
| if (r != PAM_SUCCESS) { |
| pam_syslog(handle, LOG_ERR, "Failed to set bus variable."); |
| return r; |
| } |
| #endif |
| return PAM_SUCCESS; |
| } |
| |
| _public_ PAM_EXTERN int pam_sm_open_session( |
| pam_handle_t *handle, |
| int flags, |
| int argc, const char **argv) { |
| |
| _cleanup_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; |
| _cleanup_bus_message_unref_ 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_bus_close_unref_ 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 *p = NULL, *rt = NULL; |
| |
| if (asprintf(&p, "/run/systemd/users/"UID_FMT, pw->pw_uid) < 0) |
| return PAM_BUF_ERR; |
| |
| r = parse_env_file(p, NEWLINE, |
| "RUNTIME", &rt, |
| NULL); |
| if (r < 0 && r != -ENOENT) |
| return PAM_SESSION_ERR; |
| |
| if (rt) { |
| 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)) |
| 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 %d 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=%u pid=%u service=%s type=%s class=%s desktop=%s seat=%s vtnr=%u 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) { |
| 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", INT_TO_PTR(session_fd+1), 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_bus_error_free_ sd_bus_error error = SD_BUS_ERROR_NULL; |
| _cleanup_bus_close_unref_ 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; |
| } |