Branch data     Line data    Source code

       1                 :            : /* SPDX-License-Identifier: LGPL-2.1+ */
       2                 :            : 
       3                 :            : #include <sys/stat.h>
       4                 :            : #include <sys/types.h>
       5                 :            : #include <unistd.h>
       6                 :            : 
       7                 :            : #include "sd-daemon.h"
       8                 :            : #include "sd-event.h"
       9                 :            : 
      10                 :            : #include "capability-util.h"
      11                 :            : #include "daemon-util.h"
      12                 :            : #include "main-func.h"
      13                 :            : #include "mkdir.h"
      14                 :            : #include "resolved-conf.h"
      15                 :            : #include "resolved-manager.h"
      16                 :            : #include "resolved-resolv-conf.h"
      17                 :            : #include "selinux-util.h"
      18                 :            : #include "signal-util.h"
      19                 :            : #include "user-util.h"
      20                 :            : 
      21                 :          0 : static int run(int argc, char *argv[]) {
      22                 :          0 :         _cleanup_(notify_on_cleanup) const char *notify_stop = NULL;
      23                 :          0 :         _cleanup_(manager_freep) Manager *m = NULL;
      24                 :          0 :         const char *user = "systemd-resolve";
      25                 :            :         uid_t uid;
      26                 :            :         gid_t gid;
      27                 :            :         int r;
      28                 :            : 
      29                 :          0 :         log_setup_service();
      30                 :            : 
      31         [ #  # ]:          0 :         if (argc != 1)
      32         [ #  # ]:          0 :                 return log_error_errno(SYNTHETIC_ERRNO(EINVAL), "This program takes no arguments.");
      33                 :            : 
      34                 :          0 :         umask(0022);
      35                 :            : 
      36                 :          0 :         r = mac_selinux_init();
      37         [ #  # ]:          0 :         if (r < 0)
      38         [ #  # ]:          0 :                 return log_error_errno(r, "SELinux setup failed: %m");
      39                 :            : 
      40                 :          0 :         r = get_user_creds(&user, &uid, &gid, NULL, NULL, 0);
      41         [ #  # ]:          0 :         if (r < 0)
      42         [ #  # ]:          0 :                 return log_error_errno(r, "Cannot resolve user name %s: %m", user);
      43                 :            : 
      44                 :            :         /* Always create the directory where resolv.conf will live */
      45                 :          0 :         r = mkdir_safe_label("/run/systemd/resolve", 0755, uid, gid, MKDIR_WARN_MODE);
      46         [ #  # ]:          0 :         if (r < 0)
      47         [ #  # ]:          0 :                 return log_error_errno(r, "Could not create runtime directory: %m");
      48                 :            : 
      49                 :            :         /* Drop privileges, but only if we have been started as root. If we are not running as root we assume most
      50                 :            :          * privileges are already dropped. */
      51         [ #  # ]:          0 :         if (getuid() == 0) {
      52                 :            : 
      53                 :            :                 /* Drop privileges, but keep three caps. Note that we drop those too, later on (see below) */
      54                 :          0 :                 r = drop_privileges(uid, gid,
      55                 :            :                                     (UINT64_C(1) << CAP_NET_RAW)|          /* needed for SO_BINDTODEVICE */
      56                 :            :                                     (UINT64_C(1) << CAP_NET_BIND_SERVICE)| /* needed to bind on port 53 */
      57                 :            :                                     (UINT64_C(1) << CAP_SETPCAP)           /* needed in order to drop the caps later */);
      58         [ #  # ]:          0 :                 if (r < 0)
      59         [ #  # ]:          0 :                         return log_error_errno(r, "Failed to drop privileges: %m");
      60                 :            :         }
      61                 :            : 
      62         [ #  # ]:          0 :         assert_se(sigprocmask_many(SIG_BLOCK, NULL, SIGTERM, SIGINT, SIGUSR1, SIGUSR2, SIGRTMIN+1, -1) >= 0);
      63                 :            : 
      64                 :          0 :         r = manager_new(&m);
      65         [ #  # ]:          0 :         if (r < 0)
      66         [ #  # ]:          0 :                 return log_error_errno(r, "Could not create manager: %m");
      67                 :            : 
      68                 :          0 :         r = manager_start(m);
      69         [ #  # ]:          0 :         if (r < 0)
      70         [ #  # ]:          0 :                 return log_error_errno(r, "Failed to start manager: %m");
      71                 :            : 
      72                 :            :         /* Write finish default resolv.conf to avoid a dangling symlink */
      73                 :          0 :         (void) manager_write_resolv_conf(m);
      74                 :            : 
      75                 :          0 :         (void) manager_check_resolv_conf(m);
      76                 :            : 
      77                 :            :         /* Let's drop the remaining caps now */
      78                 :          0 :         r = capability_bounding_set_drop(0, true);
      79         [ #  # ]:          0 :         if (r < 0)
      80         [ #  # ]:          0 :                 return log_error_errno(r, "Failed to drop remaining caps: %m");
      81                 :            : 
      82                 :          0 :         notify_stop = notify_start(NOTIFY_READY, NOTIFY_STOPPING);
      83                 :            : 
      84                 :          0 :         r = sd_event_loop(m->event);
      85         [ #  # ]:          0 :         if (r < 0)
      86         [ #  # ]:          0 :                 return log_error_errno(r, "Event loop failed: %m");
      87                 :            : 
      88                 :          0 :         return 0;
      89                 :            : }
      90                 :            : 
      91                 :          0 : DEFINE_MAIN_FUNCTION(run);