release/src/router/udev/udev_selinux.c

   1 /*
   2  * Copyright (C) 2004 Daniel Walsh
   3  *
   4  *      This program is free software; you can redistribute it and/or modify it
   5  *      under the terms of the GNU General Public License as published by the
   6  *      Free Software Foundation version 2 of the License.
   7  *
   8  *      This program is distributed in the hope that it will be useful, but
   9  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  10  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  *      General Public License for more details.
  12  *
  13  *      You should have received a copy of the GNU General Public License along
  14  *      with this program; if not, write to the Free Software Foundation, Inc.,
  15  *      51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
  16  *
  17  */
  18
  19 #include <stdlib.h>
  20 #include <stdio.h>
  21 #include <stddef.h>
  22 #include <unistd.h>
  23 #include <string.h>
  24 #include <fcntl.h>
  25 #include <ctype.h>
  26 #include <limits.h>
  27 #include <libgen.h>
  28 #include <errno.h>
  29 #include <selinux/selinux.h>
  30
  31 #include "udev.h"
  32 #include "udev_selinux.h"
  33
  34 static security_context_t prev_scontext = NULL;
  35
  36 static int is_selinux_running(void)
  37 {
  38         static int selinux_enabled = -1;
  39
  40         if (selinux_enabled == -1)
  41                 selinux_enabled = (is_selinux_enabled() > 0);
  42
  43         dbg("selinux=%i", selinux_enabled);
  44         return selinux_enabled;
  45 }
  46
  47 static char *get_media(const char *devname, int mode)
  48 {
  49         FILE *fp;
  50         char procfile[PATH_MAX];
  51         char mediabuf[256];
  52         int size;
  53         char *media = NULL;
  54
  55         if (!(mode & S_IFBLK))
  56                 return NULL;
  57
  58         snprintf(procfile, PATH_MAX, "/proc/ide/%s/media", devname);
  59         procfile[PATH_MAX-1] = '\0';
  60
  61         fp = fopen(procfile, "r");
  62         if (!fp)
  63                 goto out;
  64
  65         if (fgets(mediabuf, sizeof(mediabuf), fp) == NULL)
  66                 goto close_out;
  67
  68         size = strlen(mediabuf);
  69         while (size-- > 0) {
  70                 if (isspace(mediabuf[size])) {
  71                         mediabuf[size] = '\0';
  72                 } else {
  73                         break;
  74                 }
  75         }
  76
  77         media = strdup(mediabuf);
  78         info("selinux_get_media(%s)='%s'", devname, media);
  79
  80 close_out:
  81         fclose(fp);
  82 out:
  83         return media;
  84 }
  85
  86 void selinux_setfilecon(const char *file, const char *devname, unsigned int mode)
  87 {
  88         if (is_selinux_running()) {
  89                 security_context_t scontext = NULL;
  90                 char *media;
  91                 int ret = -1;
  92
  93                 if (devname) {
  94                         media = get_media(devname, mode);
  95                         if (media) {
  96                                 ret = matchmediacon(media, &scontext);
  97                                 free(media);
  98                         }
  99                 }
 100
 101                 if (ret < 0)
 102                         if (matchpathcon(file, mode, &scontext) < 0) {
 103                                 err("matchpathcon(%s) failed", file);
 104                                 return;
 105                         }
 106
 107                 if (lsetfilecon(file, scontext) < 0)
 108                         err("setfilecon %s failed: %s", file, strerror(errno));
 109
 110                 freecon(scontext);
 111         }
 112 }
 113
 114 void selinux_setfscreatecon(const char *file, const char *devname, unsigned int mode)
 115 {
 116         if (is_selinux_running()) {
 117                 security_context_t scontext = NULL;
 118                 char *media;
 119                 int ret = -1;
 120
 121                 if (devname) {
 122                         media = get_media(devname, mode);
 123                         if (media) {
 124                                 ret = matchmediacon(media, &scontext);
 125                                 free(media);
 126                         }
 127                 }
 128
 129                 if (ret < 0)
 130                         if (matchpathcon(file, mode, &scontext) < 0) {
 131                                 err("matchpathcon(%s) failed", file);
 132                                 return;
 133                         }
 134
 135                 if (setfscreatecon(scontext) < 0)
 136                         err("setfscreatecon %s failed: %s", file, strerror(errno));
 137
 138                 freecon(scontext);
 139         }
 140 }
 141
 142 void selinux_resetfscreatecon(void)
 143 {
 144         if (is_selinux_running()) {
 145                 if (setfscreatecon(prev_scontext) < 0)
 146                         err("setfscreatecon failed: %s", strerror(errno));
 147         }
 148 }
 149
 150 void selinux_init(void)
 151 {
 152         /*
 153          * record the present security context, for file-creation
 154          * restoration creation purposes.
 155          */
 156         if (is_selinux_running()) {
 157                 if (!udev_root[0])
 158                         err("selinux_init: udev_root not set");
 159                 matchpathcon_init_prefix(NULL, udev_root);
 160                 if (getfscreatecon(&prev_scontext) < 0) {
 161                         err("getfscreatecon failed");
 162                         prev_scontext = NULL;
 163                 }
 164         }
 165 }
 166
 167 void selinux_exit(void)
 168 {
 169         if (is_selinux_running() && prev_scontext) {
 170                 freecon(prev_scontext);
 171                 prev_scontext = NULL;
 172         }
 173 }