src/core/smack-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 (C) 2013 Intel Corporation
   7   Authors:
   8         Nathaniel Chen <nathaniel.chen@intel.com>
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published
  12   by the Free Software Foundation; either version 2.1 of the License,
  13   or (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 ***/
  23
  24 #include <stdio.h>
  25 #include <errno.h>
  26 #include <string.h>
  27 #include <unistd.h>
  28 #include <stdlib.h>
  29 #include <sys/vfs.h>
  30 #include <fcntl.h>
  31 #include <sys/types.h>
  32 #include <dirent.h>
  33 #include <sys/mount.h>
  34 #include <stdint.h>
  35
  36 #include "macro.h"
  37 #include "smack-setup.h"
  38 #include "util.h"
  39 #include "fileio.h"
  40 #include "log.h"
  41 #include "label.h"
  42
  43 #define SMACK_CONFIG "/etc/smack/accesses.d/"
  44 #define CIPSO_CONFIG "/etc/smack/cipso.d/"
  45
  46 #ifdef HAVE_SMACK
  47
  48 static int write_rules(const char* dstpath, const char* srcdir) {
  49         _cleanup_fclose_ FILE *dst = NULL;
  50         _cleanup_closedir_ DIR *dir = NULL;
  51         struct dirent *entry;
  52         char buf[NAME_MAX];
  53         int dfd = -1;
  54         int r = 0;
  55
  56         dst = fopen(dstpath, "we");
  57         if (!dst)  {
  58                 if (errno != ENOENT)
  59                         log_warning("Failed to open %s: %m", dstpath);
  60                 return -errno; /* negative error */
  61         }
  62
  63         /* write rules to dst from every file in the directory */
  64         dir = opendir(srcdir);
  65         if (!dir) {
  66                 if (errno != ENOENT)
  67                         log_warning("Failed to opendir %s: %m", srcdir);
  68                 return errno; /* positive on purpose */
  69         }
  70
  71         dfd = dirfd(dir);
  72         assert(dfd >= 0);
  73
  74         FOREACH_DIRENT(entry, dir, return 0) {
  75                 int fd;
  76                 _cleanup_fclose_ FILE *policy = NULL;
  77
  78                 fd = openat(dfd, entry->d_name, O_RDONLY|O_CLOEXEC);
  79                 if (fd < 0) {
  80                         if (r == 0)
  81                                 r = -errno;
  82                         log_warning("Failed to open %s: %m", entry->d_name);
  83                         continue;
  84                 }
  85
  86                 policy = fdopen(fd, "re");
  87                 if (!policy) {
  88                         if (r == 0)
  89                                 r = -errno;
  90                         safe_close(fd);
  91                         log_error("Failed to open %s: %m", entry->d_name);
  92                         continue;
  93                 }
  94
  95                 /* load2 write rules in the kernel require a line buffered stream */
  96                 FOREACH_LINE(buf, policy,
  97                              log_error("Failed to read line from %s: %m",
  98                                        entry->d_name)) {
  99                         if (!fputs(buf, dst)) {
 100                                 if (r == 0)
 101                                         r = -EINVAL;
 102                                 log_error("Failed to write line to %s", dstpath);
 103                                 break;
 104                         }
 105                         if (fflush(dst)) {
 106                                 if (r == 0)
 107                                         r = -errno;
 108                                 log_error("Failed to flush writes to %s: %m", dstpath);
 109                                 break;
 110                         }
 111                 }
 112         }
 113
 114        return r;
 115 }
 116
 117 #endif
 118
 119 int mac_smack_setup(bool *loaded_policy) {
 120
 121 #ifdef HAVE_SMACK
 122
 123         int r;
 124
 125         assert(loaded_policy);
 126
 127         r = write_rules("/sys/fs/smackfs/load2", SMACK_CONFIG);
 128         switch(r) {
 129         case -ENOENT:
 130                 log_debug("Smack is not enabled in the kernel.");
 131                 return 0;
 132         case ENOENT:
 133                 log_debug("Smack access rules directory " SMACK_CONFIG " not found");
 134                 return 0;
 135         case 0:
 136                 log_info("Successfully loaded Smack policies.");
 137                 break;
 138         default:
 139                 log_warning("Failed to load Smack access rules: %s, ignoring.",
 140                             strerror(abs(r)));
 141                 return 0;
 142         }
 143
 144 #ifdef SMACK_RUN_LABEL
 145         r = write_string_file("/proc/self/attr/current", SMACK_RUN_LABEL);
 146         if (r)
 147                 log_warning("Failed to set SMACK label \"%s\" on self: %s",
 148                             SMACK_RUN_LABEL, strerror(-r));
 149 #endif
 150
 151         r = write_rules("/sys/fs/smackfs/cipso2", CIPSO_CONFIG);
 152         switch(r) {
 153         case -ENOENT:
 154                 log_debug("Smack/CIPSO is not enabled in the kernel.");
 155                 return 0;
 156         case ENOENT:
 157                 log_debug("Smack/CIPSO access rules directory " CIPSO_CONFIG " not found");
 158                 return 0;
 159         case 0:
 160                 log_info("Successfully loaded Smack/CIPSO policies.");
 161                 break;
 162         default:
 163                 log_warning("Failed to load Smack/CIPSO access rules: %s, ignoring.",
 164                             strerror(abs(r)));
 165                 return 0;
 166         }
 167
 168         *loaded_policy = true;
 169
 170 #endif
 171
 172         return 0;
 173 }