From 8136c55a39668fc9230881f2fa0377ebb5204350 Mon Sep 17 00:00:00 2001
From: JacobBarthelmeh <jacob@wolfssl.com>
Date: Wed, 30 Mar 2022 14:02:03 -0700
Subject: [PATCH] sanity check before copy with new memory bio

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

diff --git a/src/bio.c b/src/bio.c
index c7fa37b14..e7d299aed 100644
--- a/src/bio.c
+++ b/src/bio.c
@@ -2545,7 +2545,9 @@ int wolfSSL_BIO_flush(WOLFSSL_BIO* bio)
         bio->num = (int)bio->mem_buf->max;
         bio->wrSz = len;
         bio->ptr = bio->mem_buf->data;
-        XMEMCPY(bio->ptr, buf, len);
+        if (len > 0 && bio->ptr != NULL) {
+            XMEMCPY(bio->ptr, buf, len);
+        }
 
         return bio;
     }