prevent servers from publishing an internal IP as their address

svn:r1272

src/or/config.c

@@ -345,6 +345,49 @@ static void print_usage(void) {
          );
 }
 
+int resolve_my_address(or_options_t *options) {
+  struct in_addr in;
+  struct hostent *rent;
+  char localhostname[256];
+
+  if(!options->Address) { /* then we need to guess our address */
+
+    if(gethostname(localhostname,sizeof(localhostname)) < 0) {
+      log_fn(LOG_WARN,"Error obtaining local hostname");
+      return -1;
+    }
+#if 0 /* don't worry about complaining, as long as it resolves */
+    if(!strchr(localhostname,'.')) {
+      log_fn(LOG_WARN,"fqdn '%s' has only one element. Misconfigured machine?",address);
+      log_fn(LOG_WARN,"Try setting the Address line in your config file.");
+      return -1;
+    }
+#endif
+    options->Address = tor_strdup(localhostname);
+    log_fn(LOG_DEBUG,"Guessed local host name as '%s'",options->Address);
+  }
+
+  /* now we know options->Address is set. resolve it and keep only the IP */
+
+  rent = (struct hostent *)gethostbyname(options->Address);
+  if (!rent) {
+    log_fn(LOG_WARN,"Could not resolve Address %s. Failing.", options->Address);
+    return -1;
+  }
+  assert(rent->h_length == 4);
+  memcpy(&in.s_addr, rent->h_addr,rent->h_length);
+  if(is_internal_IP(in.s_addr)) {
+    log_fn(LOG_WARN,"Address '%s' resolves to '%s'. "
+           "Please set the Address config option to be your public IP.",
+           options->Address, inet_ntoa(in));
+    return -1;
+  }
+  tor_free(options->Address);
+  options->Address = tor_strdup(inet_ntoa(in));
+  log_fn(LOG_DEBUG,"Resolved Address to %s.", options->Address);
+  return 0;
+}
+
 static void free_options(or_options_t *options) {
   tor_free(options->LogLevel);
   tor_free(options->LogFile);
@@ -525,39 +568,8 @@ int getconfig(int argc, char **argv, or_options_t *options) {
   }
 
   if(options->ORPort) { /* get an IP for ourselves */
-    struct in_addr in;
-    struct hostent *rent;
-    char localhostname[256];
-
-    if(!options->Address) { /* then we need to guess our address */
-
-      if(gethostname(localhostname,sizeof(localhostname)) < 0) {
-        log_fn(LOG_WARN,"Error obtaining local hostname");
-        return -1;
-      }
-#if 0 /* don't worry about complaining, as long as it resolves */
-      if(!strchr(localhostname,'.')) {
-        log_fn(LOG_WARN,"fqdn '%s' has only one element. Misconfigured machine?",address);
-        log_fn(LOG_WARN,"Try setting the Address line in your config file.");
-        return -1;
-      }
-#endif
-      options->Address = tor_strdup(localhostname);
-      log_fn(LOG_DEBUG,"Guessed local host name as '%s'",options->Address);
-    }
-
-    /* now we know options->Address is set. resolve it and keep only the IP */
-
-    rent = (struct hostent *)gethostbyname(options->Address);
-    if (!rent) {
-      log_fn(LOG_WARN,"Could not resolve Address %s. Failing.", options->Address);
-      return -1;
-    }
-    assert(rent->h_length == 4);
-    memcpy(&in.s_addr, rent->h_addr,rent->h_length);
-    tor_free(options->Address);
-    options->Address = tor_strdup(inet_ntoa(in));
-    log_fn(LOG_DEBUG,"Resolved Address to %s.", options->Address);
+    if(resolve_my_address(options) < 0)
+      result = -1;
   }
 
   if(options->SocksPort < 0) {