From c7b2dfbf1d41e998a03fdfcf23f54aaf901e0b88 Mon Sep 17 00:00:00 2001
From: Jacob Barthelmeh <jacob@wolfssl.com>
Date: Thu, 14 Jun 2018 17:17:07 -0600
Subject: [PATCH] sanity check on arguments with debug

---
 src/internal.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/src/internal.c b/src/internal.c
index 1ca1557..30ff771 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -2701,10 +2701,12 @@ static int DoDebug(WOLFSSH* ssh, byte* buf, word32 len, word32* idx)
     char*    msg = NULL;
     char*    lang = NULL;
     word32 strSz;
-    word32 begin = *idx;
+    word32 begin;
 
-    (void)ssh;
-    (void)len;
+    if (ssh == NULL || buf == NULL || idx == NULL || len < LENGTH_SZ + 1) {
+        return WS_BAD_ARGUMENT;
+    }
+    begin = *idx;
 
     alwaysDisplay = buf[begin++];