From 8f25db11cccf280f2bd27d2d4085468552db0f18 Mon Sep 17 00:00:00 2001
From: Jonathan Hui <jonhui@nestlabs.com>
Date: Sat, 3 Nov 2018 08:09:14 -0700
Subject: [PATCH] [coap] fix header length calculation overflow error (#3260)

Credit to OSS-Fuzz.
---
 src/core/coap/coap_header.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/core/coap/coap_header.cpp b/src/core/coap/coap_header.cpp
index 4114480ae..9ae90e6a9 100644
--- a/src/core/coap/coap_header.cpp
+++ b/src/core/coap/coap_header.cpp
@@ -170,7 +170,7 @@ otError Header::FromMessage(const Message &aMessage, uint16_t aMetadataSize)
         VerifyOrExit(mHeaderLength + optionLength <= length);
 
         aMessage.Read(offset, optionLength, mHeader.mBytes + mHeaderLength);
-        mHeaderLength += static_cast<uint8_t>(optionLength);
+        mHeaderLength += optionLength;
         offset += optionLength;
     }