login: move the PAM module to src/login/ since it is just a client to logind

1 files changed, 618 insertions, 0 deletions

diff --git a/src/login/pam-module.c b/src/login/pam-module.c
new file mode 100644
index 0000000000..14e706b374
--- /dev/null
+++ b/src/login/pam-module.c
@@ -0,0 +1,618 @@
+/*-*- 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 General Public License as published by
+  the Free Software Foundation; either version 2 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
+  General Public License for more details.
+
+  You should have received a copy of the GNU 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 "macro.h"
+#include "sd-daemon.h"
+#include "strv.h"
+#include "dbus-common.h"
+#include "def.h"
+#include "socket-util.h"
+
+static int parse_argv(pam_handle_t *handle,
+                      int argc, const char **argv,
+                      char ***controllers,
+                      char ***reset_controllers,
+                      bool *kill_processes,
+                      char ***kill_only_users,
+                      char ***kill_exclude_users,
+                      bool *debug) {
+
+        unsigned i;
+
+        assert(argc >= 0);
+        assert(argc == 0 || argv);
+
+        for (i = 0; i < (unsigned) argc; i++) {
+                int k;
+
+                if (startswith(argv[i], "kill-session-processes=")) {
+                        if ((k = parse_boolean(argv[i] + 23)) < 0) {
+                                pam_syslog(handle, LOG_ERR, "Failed to parse kill-session-processes= argument.");
+                                return k;
+                        }
+
+                        if (kill_processes)
+                                *kill_processes = k;
+
+                } else if (startswith(argv[i], "kill-session=")) {
+                        /* As compatibility for old versions */
+
+                        if ((k = parse_boolean(argv[i] + 13)) < 0) {
+                                pam_syslog(handle, LOG_ERR, "Failed to parse kill-session= argument.");
+                                return k;
+                        }
+
+                        if (kill_processes)
+                                *kill_processes = k;
+
+                } else if (startswith(argv[i], "controllers=")) {
+
+                        if (controllers) {
+                                char **l;
+
+                                if (!(l = strv_split(argv[i] + 12, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
+
+                                strv_free(*controllers);
+                                *controllers = l;
+                        }
+
+                } else if (startswith(argv[i], "reset-controllers=")) {
+
+                        if (reset_controllers) {
+                                char **l;
+
+                                if (!(l = strv_split(argv[i] + 18, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
+
+                                strv_free(*reset_controllers);
+                                *reset_controllers = l;
+                        }
+
+                } else if (startswith(argv[i], "kill-only-users=")) {
+
+                        if (kill_only_users) {
+                                char **l;
+
+                                if (!(l = strv_split(argv[i] + 16, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
+
+                                strv_free(*kill_only_users);
+                                *kill_only_users = l;
+                        }
+
+                } else if (startswith(argv[i], "kill-exclude-users=")) {
+
+                        if (kill_exclude_users) {
+                                char **l;
+
+                                if (!(l = strv_split(argv[i] + 19, ","))) {
+                                        pam_syslog(handle, LOG_ERR, "Out of memory.");
+                                        return -ENOMEM;
+                                }
+
+                                strv_free(*kill_exclude_users);
+                                *kill_exclude_users = l;
+                        }
+
+                } else if (startswith(argv[i], "debug=")) {
+                        if ((k = parse_boolean(argv[i] + 6)) < 0) {
+                                pam_syslog(handle, LOG_ERR, "Failed to parse debug= argument.");
+                                return k;
+                        }
+
+                        if (debug)
+                                *debug = k;
+
+                } else if (startswith(argv[i], "create-session=") ||
+                           startswith(argv[i], "kill-user=")) {
+
+                        pam_syslog(handle, LOG_WARNING, "Option %s not supported anymore, ignoring.", argv[i]);
+
+                } else {
+                        pam_syslog(handle, LOG_ERR, "Unknown parameter '%s'.", argv[i]);
+                        return -EINVAL;
+                }
+        }
+
+        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;
+        uid_t uid;
+        int r;
+
+        assert(handle);
+        assert(ret_username);
+        assert(ret_pw);
+
+        r = audit_loginuid_from_pid(0, &uid);
+        if (r >= 0)
+                pw = pam_modutil_getpwuid(handle, uid);
+        else {
+                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 bool check_user_lists(
+                pam_handle_t *handle,
+                uid_t uid,
+                char **kill_only_users,
+                char **kill_exclude_users) {
+
+        const char *name = NULL;
+        char **l;
+
+        assert(handle);
+
+        if (uid == 0)
+                name = "root"; /* Avoid obvious NSS requests, to suppress network traffic */
+        else {
+                struct passwd *pw;
+
+                pw = pam_modutil_getpwuid(handle, uid);
+                if (pw)
+                        name = pw->pw_name;
+        }
+
+        STRV_FOREACH(l, kill_exclude_users) {
+                uid_t u;
+
+                if (parse_uid(*l, &u) >= 0)
+                        if (u == uid)
+                                return false;
+
+                if (name && streq(name, *l))
+                        return false;
+        }
+
+        if (strv_isempty(kill_only_users))
+                return true;
+
+        STRV_FOREACH(l, kill_only_users) {
+                uid_t u;
+
+                if (parse_uid(*l, &u) >= 0)
+                        if (u == uid)
+                                return true;
+
+                if (name && streq(name, *l))
+                        return true;
+        }
+
+        return false;
+}
+
+static int get_seat_from_display(const char *display, const char **seat, uint32_t *vtnr) {
+        char *p = NULL;
+        int r;
+        int fd;
+        union sockaddr_union sa;
+        struct ucred ucred;
+        socklen_t l;
+        char *tty;
+        int v;
+
+        assert(display);
+        assert(seat);
+        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;
+
+        fd = socket(AF_UNIX, SOCK_STREAM|SOCK_CLOEXEC, 0);
+        if (fd < 0) {
+                free(p);
+                return -errno;
+        }
+
+        zero(sa);
+        sa.un.sun_family = AF_UNIX;
+        strncpy(sa.un.sun_path, p, sizeof(sa.un.sun_path)-1);
+        free(p);
+
+        if (connect(fd, &sa.sa, offsetof(struct sockaddr_un, sun_path) + strlen(sa.un.sun_path)) < 0) {
+                close_nointr_nofail(fd);
+                return -errno;
+        }
+
+        l = sizeof(ucred);
+        r = getsockopt(fd, SOL_SOCKET, SO_PEERCRED, &ucred, &l);
+        close_nointr_nofail(fd);
+
+        if (r < 0)
+                return -errno;
+
+        r = get_ctty(ucred.pid, NULL, &tty);
+        if (r < 0)
+                return r;
+
+        v = vtnr_from_tty(tty);
+        free(tty);
+
+        if (v < 0)
+                return v;
+        else if (v == 0)
+                return -ENOENT;
+
+        *seat = "seat0";
+        *vtnr = (uint32_t) v;
+
+        return 0;
+}
+
+_public_ PAM_EXTERN int pam_sm_open_session(
+                pam_handle_t *handle,
+                int flags,
+                int argc, const char **argv) {
+
+        struct passwd *pw;
+        bool kill_processes = false, debug = false;
+        const char *username, *id, *object_path, *runtime_path, *service = NULL, *tty = NULL, *display = NULL, *remote_user = NULL, *remote_host = NULL, *seat = NULL, *type, *cvtnr = NULL;
+        char **controllers = NULL, **reset_controllers = NULL, **kill_only_users = NULL, **kill_exclude_users = NULL;
+        DBusError error;
+        uint32_t uid, pid;
+        DBusMessageIter iter;
+        dbus_bool_t kp;
+        int session_fd = -1;
+        DBusConnection *bus = NULL;
+        DBusMessage *m = NULL, *reply = NULL;
+        dbus_bool_t remote;
+        int r;
+        uint32_t vtnr = 0;
+
+        assert(handle);
+
+        dbus_error_init(&error);
+
+        /* pam_syslog(handle, LOG_INFO, "pam-systemd initializing"); */
+
+        /* Make this a NOP on non-systemd systems */
+        if (sd_booted() <= 0)
+                return PAM_SUCCESS;
+
+        if (parse_argv(handle,
+                       argc, argv,
+                       &controllers, &reset_controllers,
+                       &kill_processes, &kill_only_users, &kill_exclude_users,
+                       &debug) < 0) {
+                r = PAM_SESSION_ERR;
+                goto finish;
+        }
+
+        r = get_user_data(handle, &username, &pw);
+        if (r != PAM_SUCCESS)
+                goto finish;
+
+        /* 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-shared" we simply set XDG_RUNTIME_DIR and
+         * leave. */
+
+        pam_get_item(handle, PAM_SERVICE, (const void**) &service);
+        if (streq_ptr(service, "systemd-shared")) {
+                char *p, *rt = NULL;
+
+                if (asprintf(&p, "/run/systemd/users/%lu", (unsigned long) pw->pw_uid) < 0) {
+                        r = PAM_BUF_ERR;
+                        goto finish;
+                }
+
+                r = parse_env_file(p, NEWLINE,
+                                   "RUNTIME", &rt,
+                                   NULL);
+                free(p);
+
+                if (r < 0 && r != -ENOENT) {
+                        r = PAM_SESSION_ERR;
+                        free(rt);
+                        goto finish;
+                }
+
+                if (rt)  {
+                        r = pam_misc_setenv(handle, "XDG_RUNTIME_DIR", rt, 0);
+                        free(rt);
+
+                        if (r != PAM_SUCCESS) {
+                                pam_syslog(handle, LOG_ERR, "Failed to set runtime dir.");
+                                goto finish;
+                        }
+                }
+
+                r = PAM_SUCCESS;
+                goto finish;
+        }
+
+        if (kill_processes)
+                kill_processes = check_user_lists(handle, pw->pw_uid, kill_only_users, kill_exclude_users);
+
+        dbus_connection_set_change_sigpipe(FALSE);
+
+        bus = dbus_bus_get_private(DBUS_BUS_SYSTEM, &error);
+        if (!bus) {
+                pam_syslog(handle, LOG_ERR, "Failed to connect to system bus: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
+                goto finish;
+        }
+
+        m = dbus_message_new_method_call(
+                        "org.freedesktop.login1",
+                        "/org/freedesktop/login1",
+                        "org.freedesktop.login1.Manager",
+                        "CreateSession");
+
+        if (!m) {
+                pam_syslog(handle, LOG_ERR, "Could not allocate create session message.");
+                r = PAM_BUF_ERR;
+                goto finish;
+        }
+
+        uid = pw->pw_uid;
+        pid = getpid();
+
+        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");
+        cvtnr = pam_getenv(handle, "XDG_VTNR");
+
+        service = strempty(service);
+        tty = strempty(tty);
+        display = strempty(display);
+        remote_user = strempty(remote_user);
+        remote_host = strempty(remote_host);
+        seat = strempty(seat);
+
+        if (strchr(tty, ':')) {
+                /* A tty with a colon is usually an X11 display, place
+                 * 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 = "";
+        } else if (streq(tty, "cron")) {
+                /* cron has been setting PAM_TTY to "cron" for a very long time
+                 * and it cannot stop doing that for compatibility reasons. */
+                tty = "";
+        }
+
+        if (!isempty(cvtnr))
+                safe_atou32(cvtnr, &vtnr);
+
+        if (!isempty(display) && isempty(seat) && vtnr <= 0)
+                get_seat_from_display(display, &seat, &vtnr);
+
+        type = !isempty(display) ? "x11" :
+                   !isempty(tty) ? "tty" : "unspecified";
+
+        remote = !isempty(remote_host) && !streq(remote_host, "localhost") && !streq(remote_host, "localhost.localdomain");
+
+        if (!dbus_message_append_args(m,
+                                      DBUS_TYPE_UINT32, &uid,
+                                      DBUS_TYPE_UINT32, &pid,
+                                      DBUS_TYPE_STRING, &service,
+                                      DBUS_TYPE_STRING, &type,
+                                      DBUS_TYPE_STRING, &seat,
+                                      DBUS_TYPE_UINT32, &vtnr,
+                                      DBUS_TYPE_STRING, &tty,
+                                      DBUS_TYPE_STRING, &display,
+                                      DBUS_TYPE_BOOLEAN, &remote,
+                                      DBUS_TYPE_STRING, &remote_user,
+                                      DBUS_TYPE_STRING, &remote_host,
+                                      DBUS_TYPE_INVALID)) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameters to message.");
+                r = PAM_BUF_ERR;
+                goto finish;
+        }
+
+        dbus_message_iter_init_append(m, &iter);
+
+        r = bus_append_strv_iter(&iter, controllers);
+        if (r < 0) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
+                r = PAM_BUF_ERR;
+                goto finish;
+        }
+
+        r = bus_append_strv_iter(&iter, reset_controllers);
+        if (r < 0) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
+                r = PAM_BUF_ERR;
+                goto finish;
+        }
+
+        kp = kill_processes;
+        if (!dbus_message_iter_append_basic(&iter, DBUS_TYPE_BOOLEAN, &kp)) {
+                pam_syslog(handle, LOG_ERR, "Could not attach parameter to message.");
+                r = PAM_BUF_ERR;
+                goto finish;
+        }
+
+        if (debug)
+                pam_syslog(handle, LOG_DEBUG, "Asking logind to create session: "
+                           "uid=%u pid=%u service=%s type=%s seat=%s vtnr=%u tty=%s display=%s remote=%s remote_user=%s remote_host=%s",
+                           uid, pid, service, type, seat, vtnr, tty, display, yes_no(remote), remote_user, remote_host);
+
+        reply = dbus_connection_send_with_reply_and_block(bus, m, -1, &error);
+        if (!reply) {
+                pam_syslog(handle, LOG_ERR, "Failed to create session: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
+                goto finish;
+        }
+
+        if (!dbus_message_get_args(reply, &error,
+                                   DBUS_TYPE_STRING, &id,
+                                   DBUS_TYPE_OBJECT_PATH, &object_path,
+                                   DBUS_TYPE_STRING, &runtime_path,
+                                   DBUS_TYPE_UNIX_FD, &session_fd,
+                                   DBUS_TYPE_STRING, &seat,
+                                   DBUS_TYPE_UINT32, &vtnr,
+                                   DBUS_TYPE_INVALID)) {
+                pam_syslog(handle, LOG_ERR, "Failed to parse message: %s", bus_error_message(&error));
+                r = PAM_SESSION_ERR;
+                goto finish;
+        }
+
+        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",
+                           id, object_path, runtime_path, session_fd, seat, vtnr);
+
+        r = pam_misc_setenv(handle, "XDG_SESSION_ID", id, 0);
+        if (r != PAM_SUCCESS) {
+                pam_syslog(handle, LOG_ERR, "Failed to set session id.");
+                goto finish;
+        }
+
+        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.");
+                goto finish;
+        }
+
+        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.");
+                        goto finish;
+                }
+        }
+
+        if (vtnr > 0) {
+                char buf[11];
+                snprintf(buf, sizeof(buf), "%u", vtnr);
+                char_array_0(buf);
+
+                r = pam_misc_setenv(handle, "XDG_VTNR", buf, 0);
+                if (r != PAM_SUCCESS) {
+                        pam_syslog(handle, LOG_ERR, "Failed to set virtual terminal number.");
+                        goto finish;
+                }
+        }
+
+        if (session_fd >= 0) {
+                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.");
+                        return r;
+                }
+        }
+
+        session_fd = -1;
+
+        r = PAM_SUCCESS;
+
+finish:
+        strv_free(controllers);
+        strv_free(reset_controllers);
+        strv_free(kill_only_users);
+        strv_free(kill_exclude_users);
+
+        dbus_error_free(&error);
+
+        if (bus) {
+                dbus_connection_close(bus);
+                dbus_connection_unref(bus);
+        }
+
+        if (m)
+                dbus_message_unref(m);
+
+        if (reply)
+                dbus_message_unref(reply);
+
+        if (session_fd >= 0)
+                close_nointr_nofail(session_fd);
+
+        return r;
+}
+
+_public_ PAM_EXTERN int pam_sm_close_session(
+                pam_handle_t *handle,
+                int flags,
+                int argc, const char **argv) {
+
+        const void *p = NULL;
+
+        pam_get_data(handle, "systemd.session-fd", &p);
+
+        if (p)
+                close_nointr(PTR_TO_INT(p) - 1);
+
+        return PAM_SUCCESS;
+}