udev_selinux.c

   1 /*
   2  * udev_selinux.h
   3  *
   4  * Copyright (C) 2004 Daniel Walsh
   5  *
   6  *      This program is free software; you can redistribute it and/or modify it
   7  *      under the terms of the GNU General Public License as published by the
   8  *      Free Software Foundation version 2 of the License.
   9  *
  10  *      This program is distributed in the hope that it will be useful, but
  11  *      WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *      General Public License for more details.
  14  *
  15  *      You should have received a copy of the GNU General Public License along
  16  *      with this program; if not, write to the Free Software Foundation, Inc.,
  17  *      675 Mass Ave, Cambridge, MA 02139, USA.
  18  *
  19  */
  20
  21 #include <stdlib.h>
  22 #include <stdio.h>
  23 #include <stddef.h>
  24 #include <unistd.h>
  25 #include <string.h>
  26 #include <fcntl.h>
  27 #include <ctype.h>
  28 #include <limits.h>
  29 #include <libgen.h>
  30 #include <errno.h>
  31 #include <selinux/selinux.h>
  32
  33 #include "udev_selinux.h"
  34 #include "logging.h"
  35
  36 static security_context_t prev_scontext = NULL;
  37
  38 static int is_selinux_running(void)
  39 {
  40         static int selinux_enabled = -1;
  41
  42         if (selinux_enabled == -1)
  43                 selinux_enabled = (is_selinux_enabled() > 0);
  44
  45         dbg("selinux=%i", selinux_enabled);
  46         return selinux_enabled;
  47 }
  48
  49 static char *get_media(const char *devname, int mode)
  50 {
  51         FILE *fp;
  52         char procfile[PATH_MAX];
  53         char mediabuf[256];
  54         int size;
  55         char *media = NULL;
  56
  57         if (!(mode && S_IFBLK))
  58                 return NULL;
  59
  60         snprintf(procfile, PATH_MAX, "/proc/ide/%s/media", devname);
  61         procfile[PATH_MAX-1] = '\0';
  62
  63         fp = fopen(procfile, "r");
  64         if (!fp)
  65                 goto out;
  66
  67         if (fgets(mediabuf, sizeof(mediabuf), fp) == NULL)
  68                 goto close_out;
  69
  70         size = strlen(mediabuf);
  71         while (size-- > 0) {
  72                 if (isspace(mediabuf[size])) {
  73                         mediabuf[size] = '\0';
  74                 } else {
  75                         break;
  76                 }
  77         }
  78
  79         media = strdup(mediabuf);
  80         info("selinux_get_media(%s)='%s'\n", devname, media);
  81
  82 close_out:
  83         fclose(fp);
  84 out:
  85         return media;
  86 }
  87
  88 void selinux_setfilecon(const char *file, const char *devname, unsigned int mode)
  89 {
  90         if (is_selinux_running()) {
  91                 security_context_t scontext = NULL;
  92                 char *media;
  93                 int ret = -1;
  94
  95                 media = get_media(devname, mode);
  96                 if (media) {
  97                         ret = matchmediacon(media, &scontext);
  98                         free(media);
  99                 }
 100
 101                 if (ret < 0)
 102                         if (matchpathcon(file, mode, &scontext) < 0) {
 103                                 dbg("matchpathcon(%s) failed\n", file);
 104                                 return;
 105                         }
 106
 107                 if (setfilecon(file, scontext) < 0)
 108                         dbg("setfilecon %s failed with error '%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                 media = get_media(devname, mode);
 122                 if (media) {
 123                         ret = matchmediacon(media, &scontext);
 124                         free(media);
 125                 }
 126
 127                 if (ret < 0)
 128                         if (matchpathcon(file, mode, &scontext) < 0) {
 129                                 dbg("matchpathcon(%s) failed\n", file);
 130                                 return;
 131                         }
 132
 133                 if (setfscreatecon(scontext) < 0)
 134                         dbg("setfscreatecon %s failed with error '%s'", file, strerror(errno));
 135
 136                 freecon(scontext);
 137         }
 138 }
 139
 140 void selinux_resetfscreatecon(void)
 141 {
 142         if (is_selinux_running()) {
 143                 if (setfscreatecon(prev_scontext) < 0)
 144                         dbg("setfscreatecon %s failed with error '%s'", file, strerror(errno));
 145         }
 146 }
 147
 148 void selinux_init(void)
 149 {
 150         /*
 151          * record the present security context, for file-creation
 152          * restoration creation purposes.
 153          */
 154         if (is_selinux_running()) {
 155                 if (getfscreatecon(&prev_scontext) < 0) {
 156                         dbg("getfscreatecon failed\n");
 157                         prev_scontext = NULL;
 158                 }
 159         }
 160 }
 161
 162 void selinux_exit(void)
 163 {
 164         if (is_selinux_running() && prev_scontext) {
 165                 freecon(prev_scontext);
 166                 prev_scontext = NULL;
 167         }
 168 }