pam_systemd: rename source file to match the module

1 files changed, 548 insertions, 0 deletions

diff --git a/src/login/pam_systemd.c b/src/login/pam_systemd.c
new file mode 100644
index 0000000000..262621d43f
--- /dev/null
+++ b/src/login/pam_systemd.c
@@ -0,0 +1,548 @@
+/*-*- 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 ? username : pw->pw_name;
+
+        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("/dev/kdbus", F_OK) < 0)
+                return PAM_SUCCESS;
+
+        if (asprintf(&s, KERNEL_USER_BUS_FMT ";" UNIX_USER_BUS_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_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) &&
+                !streq_ptr(remote_host, "localhost") &&
+                !streq_ptr(remote_host, "localhost.localdomain");
+
+        /* 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_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;
+}