[mutter/wip/wayland-work: 39/63] mutter-launch: simplify by removing features we don't need

[Giovanni Campagna <gcampagna src gnome org>]

commit caffb6190816afaf21c58fa9c0c16bc2ebc30e2c
Author: Giovanni Campagna <gcampagn redhat com>
Date:   Mon Aug 19 12:59:58 2013 +0200

    mutter-launch: simplify by removing features we don't need
    
    Remove the ability to launch as a different user, which we don't
    need because we're spawned by gdm or by the user manually on the
    command line.
    With that, we can also remove "security" checks.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=705861

 src/wayland/weston-launch.c |  185 +------------------------------------------
 1 files changed, 3 insertions(+), 182 deletions(-)
---
diff --git a/src/wayland/weston-launch.c b/src/wayland/weston-launch.c
index ead260c..5d5efb2 100644
--- a/src/wayland/weston-launch.c
+++ b/src/wayland/weston-launch.c
@@ -78,116 +78,6 @@ struct weston_launch {
 
 union cmsg_data { unsigned char b[4]; int fd; };
 
-static gid_t *
-read_groups(void)
-{
-       int n;
-       gid_t *groups;
-       
-       n = getgroups(0, NULL);
-
-       if (n < 0) {
-               fprintf(stderr, "Unable to retrieve groups: %m\n");
-               return NULL;
-       }
-
-       groups = malloc(n * sizeof(gid_t));
-       if (!groups)
-               return NULL;
-
-       if (getgroups(n, groups) < 0) {
-               fprintf(stderr, "Unable to retrieve groups: %m\n");
-               free(groups);
-               return NULL;
-       }
-       return groups;
-}
-
-static int
-weston_launch_allowed(struct weston_launch *wl)
-{
-       struct group *gr;
-       gid_t *groups;
-       int i;
-#ifdef HAVE_SYSTEMD_LOGIN
-       char *session, *seat;
-       int err;
-#endif
-
-       if (getuid() == 0)
-               return 1;
-
-       gr = getgrnam("weston-launch");
-       if (gr) {
-               groups = read_groups();
-               if (groups) {
-                       for (i = 0; groups[i]; ++i) {
-                               if (groups[i] == gr->gr_gid) {
-                                       free(groups);
-                                       return 1;
-                               }
-                       }
-                       free(groups);
-               }
-       }
-
-#ifdef HAVE_SYSTEMD_LOGIN
-       err = sd_pid_get_session(getpid(), &session);
-       if (err == 0 && session) {
-               if (sd_session_is_active(session) &&
-                   sd_session_get_seat(session, &seat) == 0) {
-                       free(seat);
-                       free(session);
-                       return 1;
-               }
-               free(session);
-       }
-#endif
-       
-       return 0;
-}
-
-static int
-pam_conversation_fn(int msg_count,
-                   const struct pam_message **messages,
-                   struct pam_response **responses,
-                   void *user_data)
-{
-       return PAM_SUCCESS;
-}
-
-static int
-setup_pam(struct weston_launch *wl)
-{
-       int err;
-
-       wl->pc.conv = pam_conversation_fn;
-       wl->pc.appdata_ptr = wl;
-
-       err = pam_start("login", wl->pw->pw_name, &wl->pc, &wl->ph);
-       if (err != PAM_SUCCESS) {
-               fprintf(stderr, "failed to start pam transaction: %d: %s\n",
-                       err, pam_strerror(wl->ph, err));
-               return -1;
-       }
-
-       err = pam_set_item(wl->ph, PAM_TTY, ttyname(wl->tty));
-       if (err != PAM_SUCCESS) {
-               fprintf(stderr, "failed to set PAM_TTY item: %d: %s\n",
-                       err, pam_strerror(wl->ph, err));
-               return -1;
-       }
-
-       err = pam_open_session(wl->ph, 0);
-       if (err != PAM_SUCCESS) {
-               fprintf(stderr, "failed to open pam session: %d: %s\n",
-                       err, pam_strerror(wl->ph, err));
-               return -1;
-       }
-
-       return 0;
-}
-
 static int
 setup_launcher_socket(struct weston_launch *wl)
 {
@@ -468,27 +358,14 @@ setup_tty(struct weston_launch *wl, const char *tty)
        struct stat buf;
        char *t;
 
-       if (!wl->new_user) {
-               wl->tty = STDIN_FILENO;
-       } else if (tty) {
+       if (tty) {
                t = ttyname(STDIN_FILENO);
                if (t && strcmp(t, tty) == 0)
                        wl->tty = STDIN_FILENO;
                else
                        wl->tty = open(tty, O_RDWR | O_NOCTTY);
        } else {
-               int tty0 = open("/dev/tty0", O_WRONLY | O_CLOEXEC);
-               char filename[16];
-
-               if (tty0 < 0)
-                       error(1, errno, "could not open tty0");
-
-               if (ioctl(tty0, VT_OPENQRY, &wl->ttynr) < 0 || wl->ttynr == -1)
-                       error(1, errno, "failed to find non-opened console"); 
-
-               snprintf(filename, sizeof filename, "/dev/tty%d", wl->ttynr);
-               wl->tty = open(filename, O_RDWR | O_NOCTTY);
-               close(tty0);
+               wl->tty = STDIN_FILENO;
        }
 
        if (wl->tty < 0)
@@ -508,39 +385,6 @@ setup_tty(struct weston_launch *wl, const char *tty)
 }
 
 static void
-setup_session(struct weston_launch *wl)
-{
-       char **env;
-       char *term;
-       int i;
-
-       if (wl->tty != STDIN_FILENO) {
-               if (setsid() < 0)
-                       error(1, errno, "setsid failed");
-               if (ioctl(wl->tty, TIOCSCTTY, 0) < 0)
-                       error(1, errno, "TIOCSCTTY failed - tty is in use");
-       }
-
-       term = getenv("TERM");
-       clearenv();
-       if (term)
-               setenv("TERM", term, 1);
-       setenv("USER", wl->pw->pw_name, 1);
-       setenv("LOGNAME", wl->pw->pw_name, 1);
-       setenv("HOME", wl->pw->pw_dir, 1);
-       setenv("SHELL", wl->pw->pw_shell, 1);
-
-       env = pam_getenvlist(wl->ph);
-       if (env) {
-               for (i = 0; env[i]; ++i) {
-                       if (putenv(env[i]) < 0)
-                               error(0, 0, "putenv %s failed", env[i]);
-               }
-               free(env);
-       }
-}
-
-static void
 drop_privileges(struct weston_launch *wl)
 {
        if (setgid(wl->pw->pw_gid) < 0 ||
@@ -561,8 +405,6 @@ launch_compositor(struct weston_launch *wl, int argc, char *argv[])
 
        if (wl->verbose)
                printf("weston-launch: spawned weston with pid: %d\n", getpid());
-       if (wl->new_user)
-               setup_session(wl);
 
        drop_privileges(wl);
 
@@ -611,7 +453,6 @@ main(int argc, char *argv[])
        int i, c;
        char *tty = NULL;
        struct option opts[] = {
-               { "user",    required_argument, NULL, 'u' },
                { "tty",     required_argument, NULL, 't' },
                { "verbose", no_argument,       NULL, 'v' },
                { "help",    no_argument,       NULL, 'h' },
@@ -622,11 +463,6 @@ main(int argc, char *argv[])
 
        while ((c = getopt_long(argc, argv, "u:t::vh", opts, &i)) != -1) {
                switch (c) {
-               case 'u':
-                       wl.new_user = optarg;
-                       if (getuid() != 0)
-                               error(1, 0, "Permission denied. -u allowed for root only");
-                       break;
                case 't':
                        tty = optarg;
                        break;
@@ -646,28 +482,13 @@ main(int argc, char *argv[])
            strcmp (argv[optind], "gnome-shell-wayland"))
          error(1, 0, "mutter-launch can only be used to launch mutter or gnome-shell");
 
-       if (wl.new_user)
-               wl.pw = getpwnam(wl.new_user);
-       else
-               wl.pw = getpwuid(getuid());
+       wl.pw = getpwuid(getuid());
        if (wl.pw == NULL)
                error(1, errno, "failed to get username");
 
-       if (!weston_launch_allowed(&wl))
-               error(1, 0, "Permission denied. You should either:\n"
-#ifdef HAVE_SYSTEMD_LOGIN
-                     " - run from an active and local (systemd) session.\n"
-#else
-                     " - enable systemd session support for weston-launch.\n"
-#endif
-                     " - or add yourself to the 'weston-launch' group.");
-
        if (setup_tty(&wl, tty) < 0)
                exit(EXIT_FAILURE);
 
-       if (wl.new_user && setup_pam(&wl) < 0)
-               exit(EXIT_FAILURE);
-
        if (setup_launcher_socket(&wl) < 0)
                exit(EXIT_FAILURE);