From 5e03ac13f6c2e1c8f32f8a09bdbd49f1403a1e71 Mon Sep 17 00:00:00 2001
From: John Safranek <john@wolfssl.com>
Date: Wed, 16 Jan 2019 15:52:03 -0800
Subject: [PATCH] TLS Record Fragment Size Check Change Fixed a potential bug
 with respect to processing fragmented handshake messages. If a handshake
 message is fragmented across multiple TLS records and the last fragment's
 record has the next handshake message in it, we would throw a buffer error
 instead of processing the next message. Changed this so it will finish the
 handshake message and return out to process the next message. Also changed
 the handling of the handshake message to follow the calling pattern.

---
 src/internal.c | 19 ++++++++++---------
 1 file changed, 10 insertions(+), 9 deletions(-)

diff --git a/src/internal.c b/src/internal.c
index 87266bf19..af78a14c7 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -10953,11 +10953,14 @@ static int DoHandShakeMsg(WOLFSSL* ssl, byte* input, word32* inOutIdx,
         ret = DoHandShakeMsgType(ssl, input, inOutIdx, type, size, totalSz);
     }
     else {
-        if (inputLength + ssl->arrays->pendingMsgOffset
-                                                  > ssl->arrays->pendingMsgSz) {
+        word32 pendSz =
+            ssl->arrays->pendingMsgSz - ssl->arrays->pendingMsgOffset;
 
-            return BUFFER_ERROR;
-        }
+        /* Catch the case where there may be the remainder of a fragmented
+         * handshake message and the next handshake message in the same
+         * record. */
+        if (inputLength > pendSz)
+            inputLength = pendSz;
 
         XMEMCPY(ssl->arrays->pendingMsg + ssl->arrays->pendingMsgOffset,
                 input + *inOutIdx, inputLength);
@@ -10966,13 +10969,11 @@ static int DoHandShakeMsg(WOLFSSL* ssl, byte* input, word32* inOutIdx,
 
         if (ssl->arrays->pendingMsgOffset == ssl->arrays->pendingMsgSz)
         {
-            word32 idx = 0;
+            word32 idx = HANDSHAKE_HEADER_SZ;
             ret = DoHandShakeMsgType(ssl,
-                                     ssl->arrays->pendingMsg
-                                                          + HANDSHAKE_HEADER_SZ,
+                                     ssl->arrays->pendingMsg,
                                      &idx, ssl->arrays->pendingMsgType,
-                                     ssl->arrays->pendingMsgSz
-                                                          - HANDSHAKE_HEADER_SZ,
+                                     ssl->arrays->pendingMsgSz - idx,
                                      ssl->arrays->pendingMsgSz);
         #ifdef WOLFSSL_ASYNC_CRYPT
             if (ret == WC_PENDING_E) {