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 "mount-setup.h"
  34 #include "macro.h"
  35 #include "util.h"
  36 #include "log.h"
  37 #include "label.h"
  38
  39 #ifdef HAVE_SELINUX
  40 static int null_log(int type, const char *fmt, ...) {
  41         return 0;
  42 }
  43 #endif
  44
  45 int selinux_setup(bool *loaded_policy) {
  46
  47 #ifdef HAVE_SELINUX
  48        int enforce = 0;
  49        usec_t before_load, after_load;
  50        security_context_t con;
  51        int r;
  52        union selinux_callback cb;
  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        /* Make sure getcon() works, which needs /proc and /sys */
  61        mount_setup_early();
  62
  63        /* Already initialized by somebody else? */
  64        r = getcon_raw(&con);
  65        if (r == 0) {
  66                bool initialized;
  67
  68                initialized = !streq(con, "kernel");
  69                freecon(con);
  70
  71                if (initialized)
  72                        return 0;
  73        }
  74
  75        /* Make sure we have no fds open while loading the policy and
  76         * transitioning */
  77        log_close();
  78
  79        /* Now load the policy */
  80        before_load = now(CLOCK_MONOTONIC);
  81        r = selinux_init_load_policy(&enforce);
  82        if (r == 0) {
  83                char timespan[FORMAT_TIMESPAN_MAX];
  84                char *label;
  85
  86                label_retest_selinux();
  87
  88                /* Transition to the new context */
  89                r = label_get_create_label_from_exe(SYSTEMD_BINARY_PATH, &label);
  90                if (r < 0 || label == NULL) {
  91                        log_open();
  92                        log_error("Failed to compute init label, ignoring.");
  93                } else {
  94                        r = setcon(label);
  95
  96                        log_open();
  97                        if (r < 0)
  98                                log_error("Failed to transition into init label '%s', ignoring.", label);
  99
 100                        label_free(label);
 101                }
 102
 103                after_load = now(CLOCK_MONOTONIC);
 104
 105                log_info("Successfully loaded SELinux policy in %s.",
 106                          format_timespan(timespan, sizeof(timespan), after_load - before_load));
 107
 108                *loaded_policy = true;
 109
 110        } else {
 111                log_open();
 112
 113                if (enforce > 0) {
 114                        log_error("Failed to load SELinux policy. Freezing.");
 115                        return -EIO;
 116                } else
 117                        log_debug("Unable to load SELinux policy. Ignoring.");
 118        }
 119 #endif
 120
 121        return 0;
 122 }