From 6b6d003f43cbbf01b40cedb0cc12ada2e81461f9 Mon Sep 17 00:00:00 2001
From: rl1987 <rl1987@sdf.lonestar.org>
Date: Wed, 21 Feb 2018 20:23:21 +0100
Subject: Don't explode on NULL or empty string

---
 src/common/util.c    |  9 +++++++--
 src/test/test_util.c | 13 +++++++++++++
 2 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/common/util.c b/src/common/util.c
index 1402462fb0..53e117f24c 100644
--- a/src/common/util.c
+++ b/src/common/util.c
@@ -1081,8 +1081,13 @@ string_is_valid_dest(const char *string)
   int retval;
   size_t len = strlen(string);
 
-  tor_assert(string);
-  tor_assert(len > 0);
+  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);
diff --git a/src/test/test_util.c b/src/test/test_util.c
index ee9b16494c..c734426a5a 100644
--- a/src/test/test_util.c
+++ b/src/test/test_util.c
@@ -5541,6 +5541,18 @@ test_util_max_mem(void *arg)
   ;
 }
 
+static void
+test_util_dest_validation_edgecase(void *arg)
+{
+  (void)arg;
+
+  tt_assert(!string_is_valid_dest(NULL));
+  tt_assert(!string_is_valid_dest(""));
+
+  done:
+  return;
+}
+
 static void
 test_util_hostname_validation(void *arg)
 {
@@ -6222,6 +6234,7 @@ struct testcase_t util_tests[] = {
     &passthrough_setup, (void*)"1" },
   UTIL_TEST(max_mem, 0),
   UTIL_TEST(hostname_validation, 0),
+  UTIL_TEST(dest_validation_edgecase, 0),
   UTIL_TEST(ipv4_validation, 0),
   UTIL_TEST(writepid, 0),
   UTIL_TEST(get_avail_disk_space, 0),
-- 
cgit v1.2.3-54-g00ecf