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) {
  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         }
  95
  96         if (r < 0) {
  97                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
  98                          "Unable to fix label of %s: %m", path);
  99                 r = security_getenforce() == 1 ? -errno : 0;
 100         }
 101 #endif
 102
 103         return r;
 104 }
 105
 106 void label_finish(void) {
 107
 108 #ifdef HAVE_SELINUX
 109         if (use_selinux() && label_hnd)
 110                 selabel_close(label_hnd);
 111 #endif
 112 }
 113
 114 int label_get_socket_label_from_exe(const char *exe, char **label) {
 115
 116         int r = 0;
 117
 118 #ifdef HAVE_SELINUX
 119         security_context_t mycon = NULL, fcon = NULL;
 120         security_class_t sclass;
 121
 122         if (!use_selinux()) {
 123                 *label = NULL;
 124                 return 0;
 125         }
 126
 127         r = getcon(&mycon);
 128         if (r < 0)
 129                 goto fail;
 130
 131         r = getfilecon(exe, &fcon);
 132         if (r < 0)
 133                 goto fail;
 134
 135         sclass = string_to_security_class("process");
 136         r = security_compute_create(mycon, fcon, sclass, (security_context_t *) label);
 137         if (r == 0)
 138                 log_debug("SELinux Socket context for %s will be set to %s", exe, *label);
 139
 140 fail:
 141         if (r < 0 && security_getenforce() == 1)
 142                 r = -errno;
 143
 144         freecon(mycon);
 145         freecon(fcon);
 146 #endif
 147
 148         return r;
 149 }
 150
 151 int label_fifofile_set(const char *path) {
 152         int r = 0;
 153
 154 #ifdef HAVE_SELINUX
 155         security_context_t filecon = NULL;
 156
 157         if (!use_selinux() || !label_hnd)
 158                 return 0;
 159
 160         if ((r = selabel_lookup_raw(label_hnd, &filecon, path, S_IFIFO)) == 0) {
 161                 if ((r = setfscreatecon(filecon)) < 0) {
 162                         log_error("Failed to set SELinux file context on %s: %m", path);
 163                         r = -errno;
 164                 }
 165
 166                 freecon(filecon);
 167         }
 168
 169         if (r < 0 && security_getenforce() == 0)
 170                 r = 0;
 171 #endif
 172
 173         return r;
 174 }
 175
 176 int label_socket_set(const char *label) {
 177
 178 #ifdef HAVE_SELINUX
 179         if (!use_selinux())
 180                 return 0;
 181
 182         if (setsockcreatecon((security_context_t) label) < 0) {
 183                 log_full(security_getenforce() == 1 ? LOG_ERR : LOG_DEBUG,
 184                          "Failed to set SELinux context (%s) on socket: %m", label);
 185
 186                 if (security_getenforce() == 1)
 187                         return -errno;
 188         }
 189 #endif
 190
 191         return 0;
 192 }
 193
 194 void label_file_clear(void) {
 195
 196 #ifdef HAVE_SELINUX
 197         if (!use_selinux())
 198                 return;
 199
 200         setfscreatecon(NULL);
 201 #endif
 202 }
 203
 204 void label_socket_clear(void) {
 205
 206 #ifdef HAVE_SELINUX
 207         if (!use_selinux())
 208                 return;
 209
 210         setsockcreatecon(NULL);
 211 #endif
 212 }
 213
 214 void label_free(const char *label) {
 215
 216 #ifdef HAVE_SELINUX
 217         if (!use_selinux())
 218                 return;
 219
 220         freecon((security_context_t) label);
 221 #endif
 222 }
 223
 224 int label_mkdir(
 225         const char *path,
 226         mode_t mode) {
 227
 228         /* Creates a directory and labels it according to the SELinux policy */
 229
 230 #ifdef HAVE_SELINUX
 231         int r;
 232         security_context_t fcon = NULL;
 233
 234         if (use_selinux() && label_hnd) {
 235
 236                 if (path[0] == '/')
 237                         r = selabel_lookup_raw(label_hnd, &fcon, path, mode);
 238                 else {
 239                         char *cwd = NULL, *newpath = NULL;
 240
 241                         cwd = get_current_dir_name();
 242
 243                         if (cwd || asprintf(&newpath, "%s/%s", cwd, path) < 0) {
 244                                 free(cwd);
 245                                 return -errno;
 246                         }
 247
 248                         r = selabel_lookup_raw(label_hnd, &fcon, newpath, mode);
 249                         free(cwd);
 250                         free(newpath);
 251                 }
 252
 253                 if (r == 0)
 254                         r = setfscreatecon(fcon);
 255
 256                 if (r < 0 && errno != ENOENT) {
 257                         log_error("Failed to set security context %s for %s: %m", fcon, path);
 258                         r = -errno;
 259
 260                         if (security_getenforce() == 1)
 261                                 goto finish;
 262                 }
 263         }
 264
 265         if ((r = mkdir(path, mode)) < 0)
 266                 r = -errno;
 267
 268 finish:
 269         if (use_selinux() && label_hnd) {
 270                 setfscreatecon(NULL);
 271                 freecon(fcon);
 272         }
 273
 274         return r;
 275 #else
 276         return mkdir(path, mode);
 277 #endif
 278 }