From cb5123fa86982c75f2c8061b58ac51c9e9938fdb Mon Sep 17 00:00:00 2001
From: Andres Amaya Garcia <andres.amayagarcia@arm.com>
Date: Wed, 6 Dec 2017 09:39:23 +0000
Subject: [PATCH] Ensure memcpy is not called with NULL and 0 args in x509
 module

---
 library/x509_crl.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/library/x509_crl.c b/library/x509_crl.c
index 8f98d8c92..9422457b5 100644
--- a/library/x509_crl.c
+++ b/library/x509_crl.c
@@ -294,7 +294,9 @@ int mbedtls_x509_crl_parse_der( mbedtls_x509_crl *chain,
     /*
      * Copy raw DER-encoded CRL
      */
-    if( buflen != 0 && ( ( p = mbedtls_calloc( 1, buflen ) ) == NULL ) )
+    if( buflen == 0 )
+        return( MBEDTLS_ERR_X509_INVALID_FORMAT );
+    else if( ( p = mbedtls_calloc( 1, buflen ) ) == NULL )
         return( MBEDTLS_ERR_X509_ALLOC_FAILED );
 
     memcpy( p, buf, buflen );