From 8bd304e4c546e971876a4d5029f8d41bac747371 Mon Sep 17 00:00:00 2001
From: Kareem <kareem@wolfssl.com>
Date: Fri, 23 Jul 2021 11:15:40 -0700
Subject: [PATCH] Fix signed comparison issue with serialSz.

---
 wolfcrypt/src/asn.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/wolfcrypt/src/asn.c b/wolfcrypt/src/asn.c
index 698dbb18e..704e53cc4 100644
--- a/wolfcrypt/src/asn.c
+++ b/wolfcrypt/src/asn.c
@@ -10694,13 +10694,13 @@ int GetSerialNumber(const byte* input, word32* inOutIdx,
     if (ret != 0)
         return ret;
 
-    if (*serialSz > EXTERNAL_SERIAL_SIZE) {
+    if (*serialSz > EXTERNAL_SERIAL_SIZE || *serialSz <= 0) {
         WOLFSSL_MSG("Serial size bad");
         return ASN_PARSE_E;
     }
 
     /* return serial */
-    XMEMCPY(serial, &input[*inOutIdx], *serialSz);
+    XMEMCPY(serial, &input[*inOutIdx], (size_t)*serialSz);
     *inOutIdx += *serialSz;
 
     return result;