src/label.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 General Public License as published by
  10   the Free Software Foundation; either version 2 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   General Public License for more details.
  17
  18   You should have received a copy of the GNU General Public License
  19   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <errno.h>
  23 #include <sys/stat.h>
  24 #include <unistd.h>
  25
  26 #include "label.h"
  27 #include "util.h"
  28
  29 #ifdef HAVE_SELINUX
  30 #include <selinux/selinux.h>
  31 #include <selinux/label.h>
  32
  33 static struct selabel_handle *label_hnd = NULL;
  34
  35 static inline bool use_selinux(void) {
  36         static int use_selinux_ind = -1;
  37
  38         if (use_selinux_ind < 0)
  39                 use_selinux_ind = is_selinux_enabled() > 0;
  40
  41         return use_selinux_ind;
  42 }
  43
  44 #endif
  45
  46 int label_init(void) {
  47         int r = 0;
  48
  49 #ifdef HAVE_SELINUX
  50
  51         if (!use_selinux())
  52                 return 0;
  53
  54         if (label_hnd)
  55                 return 0;
  56
  57         label_hnd = selabel_open(SELABEL_CTX_FILE, NULL, 0);
  58         if (!label_hnd) {
  59                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
  60                          "Failed to initialize SELinux context: %m");
  61                 r = security_getenforce() == 1 ? -errno : 0;
  62         }
  63 #endif
  64
  65         return r;
  66 }
  67
  68 int label_fix(const char *path, bool ignore_enoent) {
  69         int r = 0;
  70
  71 #ifdef HAVE_SELINUX
  72         struct stat st;
  73         security_context_t fcon;
  74
  75         if (!use_selinux() || !label_hnd)
  76                 return 0;
  77
  78         r = lstat(path, &st);
  79         if (r == 0) {
  80                 r = selabel_lookup_raw(label_hnd, &fcon, path, st.st_mode);
  81
  82                 /* If there's no label to set, then exit without warning */
  83                 if (r < 0 && errno == ENOENT)
  84                         return 0;
  85
  86                 if (r == 0) {
  87                         r = setfilecon(path, fcon);
  88                         freecon(fcon);
  89
  90                         /* If the FS doesn't support labels, then exit without warning */
  91                         if (r < 0 && errno == ENOTSUP)
  92                                 return 0;
  93
  94                         /* Ignore ENOENT in some cases */
  95                         if (r < 0 && ignore_enoent && errno == ENOENT)
  96                                 return 0;
  97                 }
  98         }
  99
 100         if (r < 0) {
 101                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
 102                          "Unable to fix label of %s: %m", path);
 103                 r = security_getenforce() == 1 ? -errno : 0;
 104         }
 105 #endif
 106
 107         return r;
 108 }
 109
 110 void label_finish(void) {
 111
 112 #ifdef HAVE_SELINUX
 113         if (use_selinux() && label_hnd)
 114                 selabel_close(label_hnd);
 115 #endif
 116 }
 117
 118 int label_get_socket_label_from_exe(const char *exe, char **label) {
 119
 120         int r = 0;
 121
 122 #ifdef HAVE_SELINUX
 123         security_context_t mycon = NULL, fcon = NULL;
 124         security_class_t sclass;
 125
 126         if (!use_selinux()) {
 127                 *label = NULL;
 128                 return 0;
 129         }
 130
 131         r = getcon(&mycon);
 132         if (r < 0)
 133                 goto fail;
 134
 135         r = getfilecon(exe, &fcon);
 136         if (r < 0)
 137                 goto fail;
 138
 139         sclass = string_to_security_class("process");
 140         r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label);
 141         if (r == 0)
 142                 log_debug("SELinux Socket context for %s will be set to %s", exe, *label);
 143
 144 fail:
 145         if (r < 0 && security_getenforce() == 1)
 146                 r = -errno;
 147
 148         freecon(mycon);
 149         freecon(fcon);
 150 #endif
 151
 152         return r;
 153 }
 154
 155 int label_fifofile_set(const char *path) {
 156         int r = 0;
 157
 158 #ifdef HAVE_SELINUX
 159         security_context_t filecon = NULL;
 160
 161         if (!use_selinux() || !label_hnd)
 162                 return 0;
 163
 164         if ((r = selabel_lookup_raw(label_hnd, &filecon, path, S_IFIFO)) == 0) {
 165                 if ((r = setfscreatecon(filecon)) < 0) {
 166                         log_error("Failed to set SELinux file context on %s: %m", path);
 167                         r = -errno;
 168                 }
 169
 170                 freecon(filecon);
 171         }
 172
 173         if (r < 0 && security_getenforce() == 0)
 174                 r = 0;
 175 #endif
 176
 177         return r;
 178 }
 179
 180 int label_symlinkfile_set(const char *path) {
 181         int r = 0;
 182
 183 #ifdef HAVE_SELINUX
 184         security_context_t filecon = NULL;
 185
 186         if (!use_selinux() || !label_hnd)
 187                 return 0;
 188
 189         if ((r = selabel_lookup_raw(label_hnd, &filecon, path, S_IFLNK)) == 0) {
 190                 if ((r = setfscreatecon(filecon)) < 0) {
 191                         log_error("Failed to set SELinux file context on %s: %m", path);
 192                         r = -errno;
 193                 }
 194
 195                 freecon(filecon);
 196         }
 197
 198         if (r < 0 && security_getenforce() == 0)
 199                 r = 0;
 200 #endif
 201
 202         return r;
 203 }
 204
 205 int label_socket_set(const char *label) {
 206
 207 #ifdef HAVE_SELINUX
 208         if (!use_selinux())
 209                 return 0;
 210
 211         if (setsockcreatecon((security_context_t) label) < 0) {
 212                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
 213                          "Failed to set SELinux context (%s) on socket: %m", label);
 214
 215                 if (security_getenforce() == 1)
 216                         return -errno;
 217         }
 218 #endif
 219
 220         return 0;
 221 }
 222
 223 void label_file_clear(void) {
 224
 225 #ifdef HAVE_SELINUX
 226         if (!use_selinux())
 227                 return;
 228
 229         setfscreatecon(NULL);
 230 #endif
 231 }
 232
 233 void label_socket_clear(void) {
 234
 235 #ifdef HAVE_SELINUX
 236         if (!use_selinux())
 237                 return;
 238
 239         setsockcreatecon(NULL);
 240 #endif
 241 }
 242
 243 void label_free(const char *label) {
 244
 245 #ifdef HAVE_SELINUX
 246         if (!use_selinux())
 247                 return;
 248
 249         freecon((security_context_t) label);
 250 #endif
 251 }
 252
 253 int label_mkdir(
 254         const char *path,
 255         mode_t mode) {
 256
 257         /* Creates a directory and labels it according to the SELinux policy */
 258
 259 #ifdef HAVE_SELINUX
 260         int r;
 261         security_context_t fcon = NULL;
 262
 263         if (use_selinux() && label_hnd) {
 264
 265                 if (path_is_absolute(path))
 266                         r = selabel_lookup_raw(label_hnd, &fcon, path, mode);
 267                 else {
 268                         char *newpath = NULL;
 269
 270                         if (!(newpath = path_make_absolute_cwd(path)))
 271                                 return -ENOMEM;
 272
 273                         r = selabel_lookup_raw(label_hnd, &fcon, newpath, mode);
 274                         free(newpath);
 275                 }
 276
 277                 if (r == 0)
 278                         r = setfscreatecon(fcon);
 279
 280                 if (r < 0 && errno != ENOENT) {
 281                         log_error("Failed to set security context %s for %s: %m", fcon, path);
 282                         r = -errno;
 283
 284                         if (security_getenforce() == 1)
 285                                 goto finish;
 286                 }
 287         }
 288
 289         if ((r = mkdir(path, mode)) < 0)
 290                 r = -errno;
 291
 292 finish:
 293         if (use_selinux() && label_hnd) {
 294                 setfscreatecon(NULL);
 295                 freecon(fcon);
 296         }
 297
 298         return r;
 299 #else
 300         return mkdir(path, mode);
 301 #endif
 302 }