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 <unistd.h>
  23 #include <stdio.h>
  24 #include <errno.h>
  25 #include <string.h>
  26 #include <stdlib.h>
  27
  28 #ifdef HAVE_SELINUX
  29 #include <selinux/selinux.h>
  30 #endif
  31
  32 #include "selinux-setup.h"
  33 #include "selinux-util.h"
  34 #include "label.h"
  35 #include "mount-setup.h"
  36 #include "macro.h"
  37 #include "util.h"
  38 #include "log.h"
  39
  40 #ifdef HAVE_SELINUX
  41 static int null_log(int type, const char *fmt, ...) {
  42         return 0;
  43 }
  44 #endif
  45
  46 int selinux_setup(bool *loaded_policy) {
  47
  48 #ifdef HAVE_SELINUX
  49         int enforce = 0;
  50         usec_t before_load, after_load;
  51         security_context_t con;
  52         int r;
  53         union selinux_callback cb;
  54         bool initialized = false;
  55
  56         assert(loaded_policy);
  57
  58         /* Turn off all of SELinux' own logging, we want to do that */
  59         cb.func_log = null_log;
  60         selinux_set_callback(SELINUX_CB_LOG, cb);
  61
  62         /* Don't load policy in the initrd if we don't appear to have
  63          * it.  For the real root, we check below if we've already
  64          * loaded policy, and return gracefully.
  65          */
  66         if (in_initrd() && access(selinux_path(), F_OK) < 0)
  67                 return 0;
  68
  69         /* Already initialized by somebody else? */
  70         r = getcon_raw(&con);
  71         if (r == 0) {
  72                 initialized = !streq(con, "kernel");
  73                 freecon(con);
  74         }
  75
  76         /* Make sure we have no fds open while loading the policy and
  77          * transitioning */
  78         log_close();
  79
  80         /* Now load the policy */
  81         before_load = now(CLOCK_MONOTONIC);
  82         r = selinux_init_load_policy(&enforce);
  83         if (r == 0) {
  84                 char timespan[FORMAT_TIMESPAN_MAX];
  85                 char *label;
  86
  87                 retest_selinux();
  88
  89                 /* Transition to the new context */
  90                 r = label_get_create_label_from_exe(SYSTEMD_BINARY_PATH, &label);
  91                 if (r < 0 || label == NULL) {
  92                         log_open();
  93                         log_error("Failed to compute init label, ignoring.");
  94                 } else {
  95                         r = setcon(label);
  96
  97                         log_open();
  98                         if (r < 0)
  99                                 log_error("Failed to transition into init label '%s', ignoring.", label);
 100
 101                         label_free(label);
 102                 }
 103
 104                 after_load = now(CLOCK_MONOTONIC);
 105
 106                 log_info("Successfully loaded SELinux policy in %s.",
 107                          format_timespan(timespan, sizeof(timespan), after_load - before_load, 0));
 108
 109                 *loaded_policy = true;
 110
 111         } else {
 112                 log_open();
 113
 114                 if (enforce > 0) {
 115                         if (!initialized) {
 116                                 log_error("Failed to load SELinux policy. Freezing.");
 117                                 return -EIO;
 118                         }
 119
 120                         log_warning("Failed to load new SELinux policy. Continuing with old policy.");
 121                 } else
 122                         log_debug("Unable to load SELinux policy. Ignoring.");
 123         }
 124 #endif
 125
 126         return 0;
 127 }