From e4d1558aa2c1c04a05066ee8600f37603890ba8c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tim=20R=C3=BChsen?= <tim.ruehsen@gmx.de>
Date: Wed, 9 Jan 2019 14:36:16 +0100
Subject: [PATCH] idn2_to_ascii_4i(): Restrict output length to 63

---
 lib/lookup.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/lib/lookup.c b/lib/lookup.c
index 7c5b52bb..cc918d95 100644
--- a/lib/lookup.c
+++ b/lib/lookup.c
@@ -617,10 +617,18 @@ idn2_to_ascii_4i (const uint32_t * input, size_t inlen, char * output, int flags
        * char * out  output zero terminated string that must have room for at
        * least 63 characters plus the terminating zero.
        */
+      size_t len = strlen ((char *) output_u8);
+
+      if (len > 63)
+        {
+	  free (output_u8);
+	  return IDN2_TOO_BIG_DOMAIN;
+        }
+
       if (output)
-	strcpy (output, (const char *) output_u8);
+	strcpy (output, (char *) output_u8);
 
-      free(output_u8);
+      free (output_u8);
     }
 
   return rc;
-- 
2.22.0