From 4fa4d6d22708231a51bdff93ef3220aa95b6fc80 Mon Sep 17 00:00:00 2001
From: Mounir IDRASSI <mounir.idrassi@idrix.fr>
Date: Sun, 31 Aug 2014 23:56:37 +0200
Subject: Windows vulnerability fix: correct possible BSOD attack targeted
 towards GetWipePassCount() / WipeBuffer() found by the Open Crypto Audit
 Project.

---
 src/Common/BootEncryption.cpp |  2 +-
 src/Common/Password.c         |  7 +++++++
 src/Common/Wipe.c             | 13 ++++++++-----
 src/Driver/DriveFilter.c      | 20 +++++++++++++++++---
 src/Format/InPlace.c          | 10 +++++++++-
 5 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/src/Common/BootEncryption.cpp b/src/Common/BootEncryption.cpp
index e57a434e..9f848fc7 100644
--- a/src/Common/BootEncryption.cpp
+++ b/src/Common/BootEncryption.cpp
@@ -2064,7 +2064,7 @@ namespace VeraCrypt
 	{
 		BootEncryptionStatus encStatus = GetStatus();
 
-		if (encStatus.SetupInProgress)
+		if (encStatus.SetupInProgress || (wipePassCount <= 0))
 			throw ParameterIncorrect (SRC_POS);
 
 		SystemDriveConfiguration config = GetSystemDriveConfiguration ();
diff --git a/src/Common/Password.c b/src/Common/Password.c
index c23bd4fa..b1fa83ef 100644
--- a/src/Common/Password.c
+++ b/src/Common/Password.c
@@ -143,6 +143,13 @@ int ChangePwd (const char *lpszVolume, Password *oldPassword, Password *newPassw
 
 	if (oldPassword->Length == 0 || newPassword->Length == 0) return -1;
 
+	if (wipePassCount <= 0)
+	{
+      nStatus = ERR_PARAMETER_INCORRECT;
+      handleError (hwndDlg, nStatus);
+      return nStatus;
+	}
+
    if (!lpszVolume)
    {
       nStatus = ERR_OUTOFMEMORY;
diff --git a/src/Common/Wipe.c b/src/Common/Wipe.c
index f06862e2..d2ee175b 100644
--- a/src/Common/Wipe.c
+++ b/src/Common/Wipe.c
@@ -157,12 +157,9 @@ int GetWipePassCount (WipeAlgorithmId algorithm)
 
 	case TC_WIPE_256:
 		return 256;
-
-	default:
-		TC_THROW_FATAL_EXCEPTION;
 	}
 
-	return 0;	// Prevent compiler warnings
+	return -1;	// Prevent compiler warnings
 }
 
 
@@ -183,8 +180,14 @@ BOOL WipeBuffer (WipeAlgorithmId algorithm, byte randChars[TC_WIPE_RAND_CHAR_COU
 	case TC_WIPE_35_GUTMANN:
 		return Wipe35Gutmann (pass, buffer, size);
 
+	/* we will never reach here because all calls to WipeBuffer are preceeded
+	 * by a call to GetWipePassCount that already checks the same algorithm
+	 * parameters and in case of unsupported value an error is returned before
+	 * calling WipeBuffer
+	 */
+   /*
 	default:
-		TC_THROW_FATAL_EXCEPTION;
+		TC_THROW_FATAL_EXCEPTION;*/
 	}
 
 	return FALSE;	// Prevent compiler warnings
diff --git a/src/Driver/DriveFilter.c b/src/Driver/DriveFilter.c
index 331b3720..26fed73d 100644
--- a/src/Driver/DriveFilter.c
+++ b/src/Driver/DriveFilter.c
@@ -1320,7 +1320,14 @@ static VOID SetupThreadProc (PVOID threadArg)
 			if (SetupRequest.WipeAlgorithm != TC_WIPE_NONE)
 			{
 				byte wipePass;
-				for (wipePass = 1; wipePass <= GetWipePassCount (SetupRequest.WipeAlgorithm); ++wipePass)
+				int wipePassCount = GetWipePassCount (SetupRequest.WipeAlgorithm);
+				if (wipePassCount <= 0)
+				{
+					SetupResult = STATUS_INVALID_PARAMETER;
+					goto err;
+				}
+
+				for (wipePass = 1; wipePass <= wipePassCount; ++wipePass)
 				{
 					if (!WipeBuffer (SetupRequest.WipeAlgorithm, wipeRandChars, wipePass, wipeBuffer, setupBlockSize))
 					{
@@ -1692,7 +1699,7 @@ static VOID DecoySystemWipeThreadProc (PVOID threadArg)
 	byte *wipeBuffer = NULL;
 	byte *wipeRandBuffer = NULL;
 	byte wipeRandChars[TC_WIPE_RAND_CHAR_COUNT];
-	int wipePass;
+	int wipePass, wipePassCount;
 	int ea = Extension->Queue.CryptoInfo->ea;
 
 	KIRQL irql;
@@ -1755,7 +1762,14 @@ static VOID DecoySystemWipeThreadProc (PVOID threadArg)
 		if (offset.QuadPart > Extension->ConfiguredEncryptedAreaEnd)
 			break;
 
-		for (wipePass = 1; wipePass <= GetWipePassCount (WipeDecoyRequest.WipeAlgorithm); ++wipePass)
+		wipePassCount = GetWipePassCount (WipeDecoyRequest.WipeAlgorithm);
+		if (wipePassCount <= 0)
+		{
+			DecoySystemWipeResult = STATUS_INVALID_PARAMETER;
+			goto err;
+		}
+
+		for (wipePass = 1; wipePass <= wipePassCount; ++wipePass)
 		{
 			if (!WipeBuffer (WipeDecoyRequest.WipeAlgorithm, wipeRandChars, wipePass, wipeBuffer, wipeBlockSize))
 			{
diff --git a/src/Format/InPlace.c b/src/Format/InPlace.c
index b1bfac98..5c8cb3b4 100644
--- a/src/Format/InPlace.c
+++ b/src/Format/InPlace.c
@@ -861,10 +861,18 @@ inplace_enc_read:
 		if (wipeAlgorithm != TC_WIPE_NONE)
 		{
 			byte wipePass;
+			int wipePassCount = GetWipePassCount (wipeAlgorithm);
+
+			if (wipePassCount <= 0)
+			{
+				SetLastError (ERROR_INVALID_PARAMETER);
+				nStatus = ERR_PARAMETER_INCORRECT;
+				goto closing_seq;
+			}
 
 			offset.QuadPart = masterCryptoInfo->EncryptedAreaStart.Value - workChunkSize;
 
-			for (wipePass = 1; wipePass <= GetWipePassCount (wipeAlgorithm); ++wipePass)
+			for (wipePass = 1; wipePass <= wipePassCount; ++wipePass)
 			{
 				if (!WipeBuffer (wipeAlgorithm, wipeRandChars, wipePass, wipeBuffer, workChunkSize))
 				{
-- 
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