From 1df42a2ca0d9788829939ad7fbfe20601d008830 Mon Sep 17 00:00:00 2001
From: Vladislav Vaintroub <wlad@mariadb.com>
Date: Tue, 28 May 2019 20:03:44 +0200
Subject: [PATCH] MDEV-19617 Assertion `src' failed in MyCTX::update

Apprently, sometimes there will be null pointers with 0 length
passed to the MyCTX::update() function, and  will need to return
a valid buffer.

So weaken the assertion, and use a valid pointer for src if it was NULL.
---
 mysys_ssl/my_crypt.cc | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/mysys_ssl/my_crypt.cc b/mysys_ssl/my_crypt.cc
index 383cec07ddd..e41ace49474 100644
--- a/mysys_ssl/my_crypt.cc
+++ b/mysys_ssl/my_crypt.cc
@@ -60,7 +60,16 @@ public:
   }
   virtual int update(const uchar *src, uint slen, uchar *dst, uint *dlen)
   {
-    DBUG_ASSERT(src);
+#ifdef HAVE_WOLFSSL
+    // WolfSSL checks parameters and does not like NULL pointers to be passed to function below.
+    if (!src)
+    {
+      static const uchar dummy[MY_AES_BLOCK_SIZE];
+      DBUG_ASSERT(!slen);
+      src=dummy;
+    }
+#endif
+
     if (EVP_CipherUpdate(ctx, dst, (int*)dlen, src, slen) != 1)
       return MY_AES_OPENSSL_ERROR;
     return MY_AES_OK;