src/core/selinux-setup.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4   This file is part of systemd.
   5
   6   Copyright 2010 Lennart Poettering
   7
   8   systemd is free software; you can redistribute it and/or modify it
   9   under the terms of the GNU Lesser General Public License as published by
  10   the Free Software Foundation; either version 2.1 of the License, or
  11   (at your option) any later version.
  12
  13   systemd is distributed in the hope that it will be useful, but
  14   WITHOUT ANY WARRANTY; without even the implied warranty of
  15   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16   Lesser General Public License for more details.
  17
  18   You should have received a copy of the GNU Lesser General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <stdio.h>
  24 #include <unistd.h>
  25
  26 #ifdef HAVE_SELINUX
  27 #include <selinux/selinux.h>
  28 #endif
  29
  30 #include "log.h"
  31 #include "macro.h"
  32 #include "selinux-util.h"
  33 #include "string-util.h"
  34 #include "util.h"
  35 #include "selinux-setup.h"
  36
  37 #ifdef HAVE_SELINUX
  38 _printf_(2,3)
  39 static int null_log(int type, const char *fmt, ...) {
  40         return 0;
  41 }
  42 #endif
  43
  44 int mac_selinux_setup(bool *loaded_policy) {
  45
  46 #ifdef HAVE_SELINUX
  47         int enforce = 0;
  48         usec_t before_load, after_load;
  49         security_context_t con;
  50         int r;
  51         union selinux_callback cb;
  52         bool initialized = false;
  53
  54         assert(loaded_policy);
  55
  56         /* Turn off all of SELinux' own logging, we want to do that */
  57         cb.func_log = null_log;
  58         selinux_set_callback(SELINUX_CB_LOG, cb);
  59
  60         /* Don't load policy in the initrd if we don't appear to have
  61          * it.  For the real root, we check below if we've already
  62          * loaded policy, and return gracefully.
  63          */
  64         if (in_initrd() && access(selinux_path(), F_OK) < 0)
  65                 return 0;
  66
  67         /* Already initialized by somebody else? */
  68         r = getcon_raw(&con);
  69         if (r == 0) {
  70                 initialized = !streq(con, "kernel");
  71                 freecon(con);
  72         }
  73
  74         /* Make sure we have no fds open while loading the policy and
  75          * transitioning */
  76         log_close();
  77
  78         /* Now load the policy */
  79         before_load = now(CLOCK_MONOTONIC);
  80         r = selinux_init_load_policy(&enforce);
  81         if (r == 0) {
  82                 _cleanup_(mac_selinux_freep) char *label = NULL;
  83                 char timespan[FORMAT_TIMESPAN_MAX];
  84
  85                 mac_selinux_retest();
  86
  87                 /* Transition to the new context */
  88                 r = mac_selinux_get_create_label_from_exe(SYSTEMD_BINARY_PATH, &label);
  89                 if (r < 0 || !label) {
  90                         log_open();
  91                         log_error("Failed to compute init label, ignoring.");
  92                 } else {
  93                         r = setcon(label);
  94
  95                         log_open();
  96                         if (r < 0)
  97                                 log_error("Failed to transition into init label '%s', ignoring.", label);
  98                 }
  99
 100                 after_load = now(CLOCK_MONOTONIC);
 101
 102                 log_info("Successfully loaded SELinux policy in %s.",
 103                          format_timespan(timespan, sizeof(timespan), after_load - before_load, 0));
 104
 105                 *loaded_policy = true;
 106
 107         } else {
 108                 log_open();
 109
 110                 if (enforce > 0) {
 111                         if (!initialized) {
 112                                 log_emergency("Failed to load SELinux policy.");
 113                                 return -EIO;
 114                         }
 115
 116                         log_warning("Failed to load new SELinux policy. Continuing with old policy.");
 117                 } else
 118                         log_debug("Unable to load SELinux policy. Ignoring.");
 119         }
 120 #endif
 121
 122         return 0;
 123 }