From 3cb7fdea950dd2d0377f0d9ad8a88fcb7c48b842 Mon Sep 17 00:00:00 2001
From: Jedidiah Barber <contact@jedbarber.id.au>
Date: Wed, 14 Jul 2021 11:27:03 +1200
Subject: Initial mirror commit

---
 Boot/Windows/BootEncryptedIo.cpp | 128 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 128 insertions(+)
 create mode 100644 Boot/Windows/BootEncryptedIo.cpp

(limited to 'Boot/Windows/BootEncryptedIo.cpp')

diff --git a/Boot/Windows/BootEncryptedIo.cpp b/Boot/Windows/BootEncryptedIo.cpp
new file mode 100644
index 0000000..4a3b98b
--- /dev/null
+++ b/Boot/Windows/BootEncryptedIo.cpp
@@ -0,0 +1,128 @@
+/*
+ Copyright (c) 2008 TrueCrypt Developers Association. All rights reserved.
+
+ Governed by the TrueCrypt License 3.0 the full text of which is contained in
+ the file License.txt included in TrueCrypt binary and source code distribution
+ packages.
+*/
+
+#include "Crypto.h"
+#include "Platform.h"
+#include "BootConfig.h"
+#include "BootDebug.h"
+#include "BootDefs.h"
+#include "BootDiskIo.h"
+#include "BootEncryptedIo.h"
+
+
+BiosResult ReadEncryptedSectors (uint16 destSegment, uint16 destOffset, byte drive, uint64 sector, uint16 sectorCount)
+{
+	BiosResult result;
+	bool decrypt = true;
+
+	if (BootCryptoInfo->hiddenVolume)
+	{
+		if (ReadWritePartiallyCoversEncryptedArea (sector, sectorCount))
+			return BiosResultInvalidFunction;
+
+		if (sector >= EncryptedVirtualPartition.StartSector && sector <= EncryptedVirtualPartition.EndSector)
+		{
+			// Remap the request to the hidden volume
+			sector -= EncryptedVirtualPartition.StartSector;
+			sector += HiddenVolumeStartSector;
+		}
+		else
+			decrypt = false;
+	}
+
+	result = ReadSectors (destSegment, destOffset, drive, sector, sectorCount);
+
+	if (result != BiosResultSuccess || !decrypt)
+		return result;
+
+	if (BootCryptoInfo->hiddenVolume)
+	{
+		// Convert sector number to data unit number of the hidden volume
+		sector -= HiddenVolumeStartSector;
+		sector += HiddenVolumeStartUnitNo;
+	}
+
+	if (drive == EncryptedVirtualPartition.Drive)
+	{
+		while (sectorCount-- > 0)
+		{
+			if (BootCryptoInfo->hiddenVolume
+				|| (sector >= EncryptedVirtualPartition.StartSector && sector <= EncryptedVirtualPartition.EndSector))
+			{
+				AcquireSectorBuffer();
+				CopyMemory (destSegment, destOffset, SectorBuffer, TC_LB_SIZE);
+
+				DecryptDataUnits (SectorBuffer, &sector, 1, BootCryptoInfo);
+
+				CopyMemory (SectorBuffer, destSegment, destOffset, TC_LB_SIZE);
+				ReleaseSectorBuffer();
+			}
+
+			++sector;
+			destOffset += TC_LB_SIZE;
+		}
+	}
+
+	return result;
+}
+
+
+BiosResult WriteEncryptedSectors (uint16 sourceSegment, uint16 sourceOffset, byte drive, uint64 sector, uint16 sectorCount)
+{
+	BiosResult result;
+	AcquireSectorBuffer();
+	uint64 dataUnitNo;
+	uint64 writeOffset;
+
+	dataUnitNo = sector;
+	writeOffset.HighPart = 0;
+	writeOffset.LowPart = 0;
+
+	if (BootCryptoInfo->hiddenVolume)
+	{
+		if (ReadWritePartiallyCoversEncryptedArea (sector, sectorCount))
+			return BiosResultInvalidFunction;
+
+		// Remap the request to the hidden volume
+		writeOffset = HiddenVolumeStartSector;
+		writeOffset -= EncryptedVirtualPartition.StartSector;
+		dataUnitNo -= EncryptedVirtualPartition.StartSector;
+		dataUnitNo += HiddenVolumeStartUnitNo;
+	}
+
+	while (sectorCount-- > 0)
+	{
+		CopyMemory (sourceSegment, sourceOffset, SectorBuffer, TC_LB_SIZE);
+
+		if (drive == EncryptedVirtualPartition.Drive && sector >= EncryptedVirtualPartition.StartSector && sector <= EncryptedVirtualPartition.EndSector)
+		{
+			EncryptDataUnits (SectorBuffer, &dataUnitNo, 1, BootCryptoInfo);
+		}
+
+		result = WriteSectors (SectorBuffer, drive, sector + writeOffset, 1);
+
+		if (result != BiosResultSuccess)
+			break;
+
+		++sector;
+		++dataUnitNo;
+		sourceOffset += TC_LB_SIZE;
+	}
+
+	ReleaseSectorBuffer();
+	return result;
+}
+
+
+static bool ReadWritePartiallyCoversEncryptedArea (const uint64 &sector, uint16 sectorCount)
+{
+	uint64 readWriteEnd = sector + --sectorCount;
+
+	return ((sector < EncryptedVirtualPartition.StartSector && readWriteEnd >= EncryptedVirtualPartition.StartSector)
+		|| (sector >= EncryptedVirtualPartition.StartSector && readWriteEnd > EncryptedVirtualPartition.EndSector));
+}
-- 
cgit