/*-*- 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 <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 "alloc-util.h" #include "audit-util.h" #include "bus-common-errors.h" #include "bus-error.h" #include "bus-util.h" #include "def.h" #include "fd-util.h" #include "fileio.h" #include "formats-util.h" #include "hostname-util.h" #include "login-util.h" #include "macro.h" #include "parse-util.h" #include "socket-util.h" #include "strv.h" #include "terminal-util.h" #include "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, 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) { _cleanup_free_ char *s = NULL; int r = PAM_BUF_ERR; if (is_kdbus_available()) { if (asprintf(&s, KERNEL_USER_BUS_ADDRESS_FMT ";" UNIX_USER_BUS_ADDRESS_FMT, uid, runtime) < 0) goto error; } else { /* 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; }