From 0980e90ee486de80b082bf77c3e4762b885b4d67 Mon Sep 17 00:00:00 2001
From: Mario Liebisch <mario.liebisch@gmail.com>
Date: Thu, 22 Jun 2017 11:24:53 +0200
Subject: [PATCH] Fixed potential buffer overrun in Win32 OpenGL error handling

This fixes issue #1245.
---
 src/SFML/Window/Win32/WglContext.cpp | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/src/SFML/Window/Win32/WglContext.cpp b/src/SFML/Window/Win32/WglContext.cpp
index 094960824..575160329 100644
--- a/src/SFML/Window/Win32/WglContext.cpp
+++ b/src/SFML/Window/Win32/WglContext.cpp
@@ -66,13 +66,17 @@ void ensureExtensionsInit(HDC deviceContext)
 ////////////////////////////////////////////////////////////
 String getErrorString(DWORD errorCode)
 {
-    std::basic_ostringstream<TCHAR, std::char_traits<TCHAR> > ss;
-    TCHAR errBuff[256];
-    FormatMessage(FORMAT_MESSAGE_FROM_SYSTEM, NULL, errorCode, 0, errBuff, sizeof(errBuff), NULL);
-    ss << errBuff;
-    String errMsg(ss.str());
+    PTCHAR buffer;
+    if (FormatMessage(FORMAT_MESSAGE_MAX_WIDTH_MASK | FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, errorCode, 0, reinterpret_cast<LPTSTR>(&buffer), 256, NULL) != 0)
+    {
+        String errMsg(buffer);
+        LocalFree(buffer);
+        return errMsg;
+    }
 
-    return errMsg;
+    std::ostringstream ss;
+    ss << "Error " << errorCode;
+    return String(ss.str());
 }