From d122b9f8b5b49363eceec24d412f7e54a442357f Mon Sep 17 00:00:00 2001
From: Jacob Barthelmeh <jacob@wolfssl.com>
Date: Fri, 24 Aug 2018 16:29:43 -0600
Subject: [PATCH] sanity check on buffer before clearing it

---
 src/internal.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/src/internal.c b/src/internal.c
index ee24ce84f..a46a44b0c 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -20019,7 +20019,9 @@ exit_scke:
 #endif
 
     /* No further need for PMS */
-    ForceZero(ssl->arrays->preMasterSecret, ssl->arrays->preMasterSz);
+    if (ssl->arrays->preMasterSecret != NULL) {
+        ForceZero(ssl->arrays->preMasterSecret, ssl->arrays->preMasterSz);
+    }
     ssl->arrays->preMasterSz = 0;
 
     /* Final cleanup */
@@ -25264,7 +25266,9 @@ static int DoSessionTicket(WOLFSSL* ssl, const byte* input, word32* inOutIdx,
     #endif /* WOLFSSL_ASYNC_CRYPT */
 
         /* Cleanup PMS */
-        ForceZero(ssl->arrays->preMasterSecret, ssl->arrays->preMasterSz);
+        if (ssl->arrays->preMasterSecret != NULL) {
+            ForceZero(ssl->arrays->preMasterSecret, ssl->arrays->preMasterSz);
+        }
         ssl->arrays->preMasterSz = 0;
 
         /* Final cleanup */