From 2c2907c2a5d9c0649e023c0d422118a041f7e74b Mon Sep 17 00:00:00 2001
From: Sean Parkinson <sean@wolfssl.com>
Date: Tue, 17 Sep 2019 11:23:43 +1000
Subject: [PATCH] Enc-Then-MAC: when message size is less than digest size
 return error

---
 src/internal.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/internal.c b/src/internal.c
index a39f91a64..cbf8e8c0f 100644
--- a/src/internal.c
+++ b/src/internal.c
@@ -13581,6 +13581,10 @@ static WC_INLINE int VerifyMacEnc(WOLFSSL* ssl, const byte* input, word32 msgSz,
 
     WOLFSSL_MSG("Verify MAC of Encrypted Data");
 
+    if (msgSz < digestSz) {
+        return VERIFY_MAC_ERROR;
+    }
+
     ret  = ssl->hmac(ssl, verify, input, msgSz - digestSz, -1, content, 1);
     ret |= ConstantCompare(verify, input + msgSz - digestSz, digestSz);
     if (ret != 0) {