From 5ee9402b7d721e9436f92f4ca9137b1a693ef065 Mon Sep 17 00:00:00 2001
From: Alkis Christidis <Christidis.Alkis@ydrogios.gr>
Date: Tue, 23 May 2017 18:17:13 +0300
Subject: [PATCH] Added SEH exception handling when calling the shellcode, so
 that the compiler doesn't die in case of an error

---
 ShellcodeCompiler/DebugUtils.cpp              | 18 +++++++--
 ShellcodeCompiler/SEHUtils.h                  | 38 +++++++++++++++++++
 ShellcodeCompiler/ShellcodeCompiler.vcxproj   |  2 +
 .../ShellcodeCompiler.vcxproj.filters         |  3 ++
 4 files changed, 58 insertions(+), 3 deletions(-)
 create mode 100644 ShellcodeCompiler/SEHUtils.h

diff --git a/ShellcodeCompiler/DebugUtils.cpp b/ShellcodeCompiler/DebugUtils.cpp
index 8364ddd..7e8586b 100644
--- a/ShellcodeCompiler/DebugUtils.cpp
+++ b/ShellcodeCompiler/DebugUtils.cpp
@@ -1,8 +1,11 @@
 
 #include "DebugUtils.h"
+#include "SEHUtils.h"
 
 // Dump all data - debug purposes
 
+
+
 void DebugUtils::DumpAllData()
 {
 	cout << endl;
@@ -53,7 +56,16 @@ void DebugUtils::TestShellcode(string p_sFilename)
 	}
 
 	// Copy shellcode and execute it
-
-	memcpy(sc, p, size);
-	(*(int(*)()) sc)();
+	try
+	{
+		_set_se_translator(CxxTranslateSehException);
+		memcpy(sc, p, size);
+		(*(int(*)()) sc)();
+	}
+	catch (const seh_exception& e)
+	{
+		cout << "Error when executing shellcode: "
+			 << e.what() << endl;
+	}
 }
+
diff --git a/ShellcodeCompiler/SEHUtils.h b/ShellcodeCompiler/SEHUtils.h
new file mode 100644
index 0000000..59385e0
--- /dev/null
+++ b/ShellcodeCompiler/SEHUtils.h
@@ -0,0 +1,38 @@
+#ifndef SEHUTILIS_H
+#define SEHUTILIS_H
+#include <windows.h>
+#include <exception>
+
+struct seh_exception : public std::exception
+{
+	seh_exception(const char* message, DWORD code) : exception(message), m_code(code) {}
+
+	DWORD Code() const { return m_code; }
+
+private:
+	const DWORD m_code;
+};
+
+void CxxTranslateSehException(unsigned int, EXCEPTION_POINTERS* pointers)
+{
+	DWORD exceptionCode = pointers->ExceptionRecord->ExceptionCode;
+	const char* msg = nullptr;
+
+	switch (exceptionCode) {
+	case EXCEPTION_ACCESS_VIOLATION:
+		msg = "Access violation.";
+		break;
+	case EXCEPTION_ARRAY_BOUNDS_EXCEEDED:
+		msg = "Out of bound access.";
+		break;
+	case EXCEPTION_ILLEGAL_INSTRUCTION:
+		msg = "Illegal instruction.";
+		break;
+	default:
+		break;
+	}
+	throw seh_exception(msg, exceptionCode);
+}
+
+
+#endif
diff --git a/ShellcodeCompiler/ShellcodeCompiler.vcxproj b/ShellcodeCompiler/ShellcodeCompiler.vcxproj
index 0c4fe0b..f53714b 100644
--- a/ShellcodeCompiler/ShellcodeCompiler.vcxproj
+++ b/ShellcodeCompiler/ShellcodeCompiler.vcxproj
@@ -134,6 +134,7 @@
       <FunctionLevelLinking>true</FunctionLevelLinking>
       <IntrinsicFunctions>true</IntrinsicFunctions>
       <PreprocessorDefinitions>NDEBUG;_CONSOLE;%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <ExceptionHandling>Async</ExceptionHandling>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
@@ -157,6 +158,7 @@
     <ClInclude Include="DLLBaseAddress.h" />
     <ClInclude Include="FunctionCalls.h" />
     <ClInclude Include="FunctionOffsetAddress.h" />
+    <ClInclude Include="SEHUtils.h" />
     <ClInclude Include="stdafx.h" />
     <ClInclude Include="StringOffsetAddress.h" />
     <ClInclude Include="targetver.h" />
diff --git a/ShellcodeCompiler/ShellcodeCompiler.vcxproj.filters b/ShellcodeCompiler/ShellcodeCompiler.vcxproj.filters
index 8bf45e7..f09e405 100644
--- a/ShellcodeCompiler/ShellcodeCompiler.vcxproj.filters
+++ b/ShellcodeCompiler/ShellcodeCompiler.vcxproj.filters
@@ -63,6 +63,9 @@
     <ClInclude Include="Compile.h">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="SEHUtils.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="stdafx.cpp">