1 files changed, 103 insertions, 0 deletions
diff --git a/tools/pe_bliss/pe_checksum.cpp b/tools/pe_bliss/pe_checksum.cpp
new file mode 100644
index 0000000000..5971a33c90
--- /dev/null
+++ b/tools/pe_bliss/pe_checksum.cpp
@@ -0,0 +1,103 @@
+/*************************************************************************/
+/* Copyright (c) 2015 dx, http://kaimi.ru                                */
+/*                                                                       */
+/* Permission is hereby granted, free of charge, to any person           */
+/* obtaining a copy of this software and associated documentation        */
+/* files (the "Software"), to deal in the Software without               */
+/* restriction, including without limitation the rights to use,          */
+/* copy, modify, merge, publish, distribute, sublicense, and/or          */
+/* sell copies of the Software, and to permit persons to whom the        */
+/* Software is furnished to do so, subject to the following conditions:  */
+/* The above copyright notice and this permission notice shall be        */
+/* included in all copies or substantial portions of the Software.       */
+/*                                                                       */
+/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,       */
+/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF    */
+/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
+/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY  */
+/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,  */
+/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE     */
+/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.                */
+/*************************************************************************/
+#include "pe_checksum.h"
+#include "pe_structures.h"
+#include "pe_base.h"
+
+namespace pe_bliss
+{
+using namespace pe_win;
+
+//Calculate checksum of image
+uint32_t calculate_checksum(std::istream& file)
+{
+	//Save istream state
+	std::ios_base::iostate state = file.exceptions();
+	std::streamoff old_offset = file.tellg();
+
+	//Checksum value
+	unsigned long long checksum = 0;
+
+	try
+	{
+		image_dos_header header;
+
+		file.exceptions(std::ios::goodbit);
+
+		//Read DOS header
+		pe_base::read_dos_header(file, header);
+
+		//Calculate PE checksum
+		file.seekg(0);
+		unsigned long long top = 0xFFFFFFFF;
+		top++;
+
+		//"CheckSum" field position in optional PE headers - it's always 64 for PE and PE+
+		static const unsigned long checksum_pos_in_optional_headers = 64;
+		//Calculate real PE headers "CheckSum" field position
+		//Sum is safe here
+		unsigned long pe_checksum_pos = header.e_lfanew + sizeof(image_file_header) + sizeof(uint32_t) + checksum_pos_in_optional_headers;
+
+		//Calculate checksum for each byte of file
+		std::streamoff filesize = pe_utils::get_file_size(file);
+		for(long long i = 0; i < filesize; i += 4)
+		{
+			unsigned long dw = 0;
+
+			//Read DWORD from file
+			file.read(reinterpret_cast<char*>(&dw), sizeof(unsigned long));
+			//Skip "CheckSum" DWORD
+			if(i == pe_checksum_pos)
+				continue;
+
+			//Calculate checksum
+			checksum = (checksum & 0xffffffff) + dw + (checksum >> 32);
+			if(checksum > top)
+				checksum = (checksum & 0xffffffff) + (checksum >> 32);
+		}
+
+		//Finish checksum
+		checksum = (checksum & 0xffff) + (checksum >> 16);
+		checksum = (checksum) + (checksum >> 16);
+		checksum = checksum & 0xffff;
+
+		checksum += static_cast<unsigned long>(filesize);
+	}
+	catch(const std::exception&)
+	{
+		//If something went wrong, restore istream state
+		file.exceptions(state);
+		file.seekg(old_offset);
+		file.clear();
+		//Rethrow
+		throw;
+	}
+
+	//Restore istream state
+	file.exceptions(state);
+	file.seekg(old_offset);
+	file.clear();
+
+	//Return checksum
+	return static_cast<uint32_t>(checksum);	
+}
+}