From d5dca62b044290475d9dd793e4abb58fbfe776d5 Mon Sep 17 00:00:00 2001
From: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date: Mon, 11 Jun 2018 00:12:32 +0200
Subject: Linux/MacOSX/FreeBSD: Support mounting partially encrypted system
 partitions/drivers in ReadOnly mode in order to allow troubleshooting in some
 cases.

---
 src/Volume/Volume.cpp | 40 +++++++++++++++++++++++++++++++++++++---
 src/Volume/Volume.h   |  4 ++++
 2 files changed, 41 insertions(+), 3 deletions(-)

(limited to 'src/Volume')

diff --git a/src/Volume/Volume.cpp b/src/Volume/Volume.cpp
index d3ef2067..d4d799d1 100644
--- a/src/Volume/Volume.cpp
+++ b/src/Volume/Volume.cpp
@@ -24,12 +24,15 @@ namespace VeraCrypt
 	Volume::Volume ()
 		: HiddenVolumeProtectionTriggered (false),
 		SystemEncryption (false),
+		VolumeDataOffset (0),
 		VolumeDataSize (0),
+		EncryptedDataSize (0),
 		TopWriteOffset (0),
 		TotalDataRead (0),
 		TotalDataWritten (0),
 		TrueCryptMode (false),
-		Pim (0)
+		Pim (0),
+		EncryptionNotCompleted (false)
 	{
 	}
 
@@ -206,6 +209,7 @@ namespace VeraCrypt
 
 					VolumeDataOffset = layout->GetDataOffset (VolumeHostSize);
 					VolumeDataSize = layout->GetDataSize (VolumeHostSize);
+					EncryptedDataSize = header->GetEncryptedAreaLength();
 
 					Header = header;
 					Layout = layout;
@@ -215,7 +219,11 @@ namespace VeraCrypt
 					if (layout->HasDriveHeader())
 					{
 						if (header->GetEncryptedAreaLength() != header->GetVolumeDataSize())
-							throw VolumeEncryptionNotCompleted (SRC_POS);
+						{
+							EncryptionNotCompleted = true;
+							// we avoid writing data to the partition since it is only partially encrypted
+							Protection = VolumeProtection::ReadOnly;
+						}
 
 						uint64 partitionStartOffset = VolumeFile->GetPartitionDeviceStartOffset();
 
@@ -223,6 +231,8 @@ namespace VeraCrypt
 							|| partitionStartOffset >= header->GetEncryptedAreaStart() + header->GetEncryptedAreaLength())
 							throw PasswordIncorrect (SRC_POS);
 
+						EncryptedDataSize -= partitionStartOffset - header->GetEncryptedAreaStart();
+
 						mode.SetSectorOffset (partitionStartOffset / ENCRYPTION_DATA_UNIT_SIZE);
 					}
 
@@ -313,7 +323,31 @@ namespace VeraCrypt
 		if (VolumeFile->ReadAt (buffer, hostOffset) != length)
 			throw MissingVolumeData (SRC_POS);
 
-		EA->DecryptSectors (buffer, hostOffset / SectorSize, length / SectorSize, SectorSize);
+		if (EncryptionNotCompleted)
+		{
+			// if encryption is not complete, we decrypt only the encrypted sectors
+			if (hostOffset < EncryptedDataSize)
+			{
+				size_t bufferOffset = 0;
+
+				// first sector is not encrypted in case of incomplete encryption
+				if (hostOffset == 0)
+				{
+					bufferOffset = (size_t) SectorSize;
+					hostOffset += SectorSize;
+					length -= SectorSize;
+				}
+
+				if (length && (hostOffset < EncryptedDataSize))
+				{
+					uint64 encryptedLength = VC_MIN (length, (EncryptedDataSize - hostOffset));
+
+					EA->DecryptSectors (buffer.GetRange (bufferOffset, encryptedLength), hostOffset / SectorSize, encryptedLength / SectorSize, SectorSize);			
+				}
+			}
+		}
+		else
+			EA->DecryptSectors (buffer, hostOffset / SectorSize, length / SectorSize, SectorSize);
 
 		TotalDataRead += length;
 	}
diff --git a/src/Volume/Volume.h b/src/Volume/Volume.h
index 311c65bc..a743a161 100644
--- a/src/Volume/Volume.h
+++ b/src/Volume/Volume.h
@@ -113,6 +113,7 @@ namespace VeraCrypt
 		uint32 GetSaltSize () const { return Header->GetSaltSize(); }
 		size_t GetSectorSize () const { return SectorSize; }
 		uint64 GetSize () const { return VolumeDataSize; }
+		uint64 GetEncryptedSize () const { return EncryptedDataSize; }
 		uint64 GetTopWriteOffset () const { return TopWriteOffset; }
 		uint64 GetTotalDataRead () const { return TotalDataRead; }
 		uint64 GetTotalDataWritten () const { return TotalDataWritten; }
@@ -127,6 +128,7 @@ namespace VeraCrypt
 		void ReadSectors (const BufferPtr &buffer, uint64 byteOffset);
 		void ReEncryptHeader (bool backupHeader, const ConstBufferPtr &newSalt, const ConstBufferPtr &newHeaderKey, shared_ptr <Pkcs5Kdf> newPkcs5Kdf);
 		void WriteSectors (const ConstBufferPtr &buffer, uint64 byteOffset);
+		bool IsEncryptionNotCompleted () const { return EncryptionNotCompleted; }
 
 	protected:
 		void CheckProtectedRange (uint64 writeHostOffset, uint64 writeLength);
@@ -146,11 +148,13 @@ namespace VeraCrypt
 		uint64 VolumeHostSize;
 		uint64 VolumeDataOffset;
 		uint64 VolumeDataSize;
+		uint64 EncryptedDataSize;
 		uint64 TopWriteOffset;
 		uint64 TotalDataRead;
 		uint64 TotalDataWritten;
 		bool TrueCryptMode;
 		int Pim;
+		bool EncryptionNotCompleted;
 
 	private:
 		Volume (const Volume &);
-- 
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