1 files changed, 59 insertions, 15 deletions

diff --git a/src/common/util.c b/src/common/util.c
index 90204befc0..f63b121672 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -16,7 +16,7 @@
 #define UTIL_PRIVATE
 #include "util.h"
 #include "torlog.h"
-#include "crypto.h"
+#include "crypto_digest.h"
 #include "torint.h"
 #include "container.h"
 #include "address.h"
@@ -1071,6 +1071,36 @@ string_is_valid_ipv6_address(const char *string)
   return (tor_inet_pton(AF_INET6,string,&addr) == 1);
 }
 
+/** Return true iff <b>string</b> is a valid destination address,
+ * i.e. either a DNS hostname or IPv4/IPv6 address string.
+ */
+int
+string_is_valid_dest(const char *string)
+{
+  char *tmp = NULL;
+  int retval;
+  size_t len;
+
+  if (string == NULL)
+    return 0;
+
+  len = strlen(string);
+
+  if (len == 0)
+    return 0;
+
+  if (string[0] == '[' && string[len - 1] == ']')
+    string = tmp = tor_strndup(string + 1, len - 2);
+
+  retval = string_is_valid_ipv4_address(string) ||
+    string_is_valid_ipv6_address(string) ||
+    string_is_valid_nonrfc_hostname(string);
+
+  tor_free(tmp);
+
+  return retval;
+}
+
 /** Return true iff <b>string</b> matches a pattern of DNS names
  * that we allow Tor clients to connect to.
  *
@@ -1078,37 +1108,51 @@ string_is_valid_ipv6_address(const char *string)
  * with misconfigured zones that have been encountered in the wild.
  */
 int
-string_is_valid_hostname(const char *string)
+string_is_valid_nonrfc_hostname(const char *string)
 {
   int result = 1;
+  int has_trailing_dot;
+  char *last_label;
   smartlist_t *components;
 
+  if (!string || strlen(string) == 0)
+    return 0;
+
+  if (string_is_valid_ipv4_address(string))
+    return 0;
+
   components = smartlist_new();
 
   smartlist_split_string(components,string,".",0,0);
 
+  if (BUG(smartlist_len(components) == 0))
+    return 0; // LCOV_EXCL_LINE should be impossible given the earlier checks.
+
+  /* Allow a single terminating '.' used rarely to indicate domains
+   * are FQDNs rather than relative. */
+  last_label = (char *)smartlist_get(components,
+                                     smartlist_len(components) - 1);
+  has_trailing_dot = (last_label[0] == '\0');
+  if (has_trailing_dot) {
+    smartlist_pop_last(components);
+    tor_free(last_label);
+    last_label = NULL;
+  }
+
   SMARTLIST_FOREACH_BEGIN(components, char *, c) {
     if ((c[0] == '-') || (*c == '_')) {
       result = 0;
       break;
     }
 
-    /* Allow a single terminating '.' used rarely to indicate domains
-     * are FQDNs rather than relative. */
-    if ((c_sl_idx > 0) && (c_sl_idx + 1 == c_sl_len) && !*c) {
-      continue;
-    }
-
     do {
-      if ((*c >= 'a' && *c <= 'z') ||
-          (*c >= 'A' && *c <= 'Z') ||
-          (*c >= '0' && *c <= '9') ||
-          (*c == '-') || (*c == '_'))
-        c++;
-      else
-        result = 0;
+      result = (TOR_ISALNUM(*c) || (*c == '-') || (*c == '_'));
+      c++;
     } while (result && *c);
 
+    if (result == 0) {
+      break;
+    }
   } SMARTLIST_FOREACH_END(c);
 
   SMARTLIST_FOREACH_BEGIN(components, char *, c) {