From 68a23293059aefbc5feeb43dbbe92e728944f170 Mon Sep 17 00:00:00 2001
From: kgv <kgv@opencascade.com>
Date: Fri, 28 Aug 2020 14:24:40 +0300
Subject: [PATCH] 0031369: Foundation Classes, Standard_ReadBuffer - access
 violation on second ::ReadChunk() call after read failure

Standard_ReadBuffer::readRawDataChunk() - do not increment NULL pointer and return invalid address.
---
 src/Standard/Standard_ReadBuffer.hxx | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/Standard/Standard_ReadBuffer.hxx b/src/Standard/Standard_ReadBuffer.hxx
index 099a9ceb81..68e0680c7a 100644
--- a/src/Standard/Standard_ReadBuffer.hxx
+++ b/src/Standard/Standard_ReadBuffer.hxx
@@ -100,6 +100,11 @@ private:
   template<typename Stream_T>
   char* readRawDataChunk (Stream_T& theStream)
   {
+    if (myBufferPtr == NULL)
+    {
+      return NULL;
+    }
+
     myBufferPtr += myChunkLen;
     if (myBufferPtr < myBufferEnd)
     {