conffile.c

   1 /* usmb - mount SMB shares via FUSE and Samba
   2  * Copyright (C) 2006-2008 Geoff Johnstone
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 3 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <assert.h>
  18 #include <errno.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include <sys/types.h>
  23 #include <sys/stat.h>
  24 #include <fcntl.h>
  25 #include <unistd.h>
  26 #include "password.h"
  27 #include "utils.h"
  28 #include "xml.h"
  29 #include "config.rng.h"
  30
  31
  32 static bool check_conf_perms (const char *conffile, int fd)
  33 {
  34   struct stat buf;
  35
  36   if (0 == fstat (fd, &buf))
  37   {
  38     if (getuid() != buf.st_uid)
  39     {
  40       fprintf (stderr, "You do not own the configuration file %s.\n", conffile);
  41       return false;
  42     }
  43
  44     if (buf.st_mode & (S_IRWXG | S_IRWXO))
  45     {
  46       fprintf (stderr, "Configuration file %s is accessible to non-owner.\n",
  47                conffile);
  48       return false;
  49     }
  50   }
  51
  52   else
  53   {
  54     fprintf (stderr, "Cannot stat configuration file %s: %s.\n",
  55              conffile, strerror (errno));
  56     return false;
  57   }
  58
  59   return true;
  60 }
  61
  62
  63 static bool conffile_read (const char *filename,
  64                            xmlDocPtr *doc,
  65                            xmlXPathContextPtr *ctx)
  66 {
  67   int fd = open (filename, O_RDONLY);
  68   if (-1 == fd)
  69   {
  70     fprintf (stderr, "Cannot open %s: %s.\n", filename, strerror (errno));
  71     return false;
  72   }
  73
  74   if (!check_conf_perms (filename, fd))
  75   {
  76     (void)close (fd);
  77     return false;
  78   }
  79
  80   *doc = xmlReadFd (fd, NULL, NULL, XML_PARSE_NONET);
  81   (void)close (fd);
  82
  83   if (NULL == *doc)
  84   {
  85     fprintf (stderr, "Cannot parse %s.\n", filename);
  86     return false;
  87   }
  88
  89   if (!xml_validate_relaxng (*doc, rng_config))
  90   {
  91     fprintf (stderr, "%s isn't a valid USMB configuration.\n", filename);
  92     xmlFreeDoc (*doc);
  93     return false;
  94   }
  95
  96   *ctx = xmlXPathNewContext (*doc);
  97   if (NULL == *ctx)
  98   {
  99     fputs ("Cannot create XPath context.\n", stderr);
 100     xmlFreeDoc (*doc);
 101     return false;
 102   }
 103
 104   return true;
 105 }
 106
 107
 108 static bool do_xpath_text (xmlXPathContextPtr ctx,
 109                            const char *parent, const char *id,
 110                            const char *child, char **out)
 111 {
 112   char xpath[2048];
 113   snprintf (xpath, sizeof (xpath),
 114             "/usmbconfig/%s[@id='%s']/%s/text()", parent, id, child);
 115   return xml_xpath_text (ctx, xpath, (void *)out);
 116 }
 117
 118
 119 bool conffile_get_mount (const char *filename, const char *key,
 120                          char **server, char **share,
 121                          char **mountpoint, char **options,
 122                          char **domain, char **username,
 123                          char **password)
 124 {
 125   xmlDocPtr doc;
 126   xmlXPathContextPtr ctx;
 127   char xp[2048];
 128   char *creds = NULL;
 129
 130   *server = *share = *mountpoint = *options = NULL;
 131   *domain = *username = *password = NULL;
 132
 133   if (strchr (key, '\''))
 134   {
 135     fprintf (stderr, "Invalid share name: %s.\n", key);
 136     return false;
 137   }
 138
 139   if (!conffile_read (filename, &doc, &ctx))
 140     return false;
 141
 142   do {
 143     if (!do_xpath_text (ctx, "mount", key, "server", server)) break;
 144     if (!do_xpath_text (ctx, "mount", key, "share", share)) break;
 145     if (!do_xpath_text (ctx, "mount", key, "mountpoint", mountpoint)) break;
 146     (void)do_xpath_text (ctx, "mount", key, "options", options);
 147
 148     snprintf (xp, sizeof (xp), "/usmbconfig/mount[@id='%s']", key);
 149     if (!xml_xpath_attr_value (ctx, xp, "credentials", &creds)) break;
 150
 151     (void)do_xpath_text (ctx, "credentials", creds, "domain", domain);
 152     if (!do_xpath_text (ctx, "credentials", creds, "username", username)) break;
 153
 154     if (!do_xpath_text (ctx, "credentials", creds, "password", password) &&
 155         !password_read (password))
 156       break;
 157
 158     xmlXPathFreeContext (ctx);
 159     xmlFreeDoc (doc);
 160
 161     return true;
 162     /*NOTREACHED*/
 163   } while (false /*CONSTCOND*/);
 164
 165   fputs ("Invalid configuration.\n", stderr);
 166
 167   xfree (*username);
 168   clear_and_free (*password);
 169   xfree (*domain);
 170   xfree (creds);
 171   xfree (*options);
 172   xfree (*mountpoint);
 173   xfree (*share);
 174   xfree (*server);
 175
 176   xmlXPathFreeContext (ctx);
 177   xmlFreeDoc (doc);
 178
 179   return false;
 180 }
 181