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Windows: Fix vulnerability inherited from TrueCrypt that allows an attacker to detect with high probability if a hidden volume is present. Vulnerability reported by Ivanov Alexey Mikhailovich.

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This commit is contained in:
Mounir IDRASSI
2016-08-08 00:49:00 +02:00
parent 3fb2eedab8
commit 5b381ce7d7
5 changed files with 286 additions and 30 deletions
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53
src/Common/Format.c
View File

@@ -566,10 +566,63 @@ begin_format:
// Fill reserved header sectors (including the backup header area) with random data
if (!volParams->hiddenVol)
{
BOOL bUpdateBackup = FALSE;
nStatus = WriteRandomDataToReservedHeaderAreas (hwndDlg, dev, cryptoInfo, dataAreaSize, FALSE, FALSE);
if (nStatus != ERR_SUCCESS)
goto error;
// write fake hidden volume header to protect against attacks that use statistical entropy
// analysis to detect presence of hidden volumes.
while (TRUE)
{
PCRYPTO_INFO dummyInfo = NULL;
LARGE_INTEGER hiddenOffset;
hiddenOffset.QuadPart = bUpdateBackup ? dataAreaSize + TC_VOLUME_HEADER_GROUP_SIZE + TC_HIDDEN_VOLUME_HEADER_OFFSET: TC_HIDDEN_VOLUME_HEADER_OFFSET;
nStatus = CreateVolumeHeaderInMemory (hwndDlg, FALSE,
header,
volParams->ea,
FIRST_MODE_OF_OPERATION_ID,
NULL,
0,
0,
NULL,
&dummyInfo,
dataAreaSize,
dataAreaSize,
dataOffset,
dataAreaSize,
0,
volParams->headerFlags,
FormatSectorSize,
FALSE);
if (nStatus != ERR_SUCCESS)
goto error;
crypto_close (dummyInfo);
if (!SetFilePointerEx ((HANDLE) dev, hiddenOffset, NULL, FILE_BEGIN))
{
nStatus = ERR_OS_ERROR;
goto error;
}
if (!WriteEffectiveVolumeHeader (volParams->bDevice, dev, header))
{
nStatus = ERR_OS_ERROR;
goto error;
}
if (bUpdateBackup)
break;
bUpdateBackup = TRUE;
}
}
#ifndef DEBUG

42
src/Common/Password.c
View File

@@ -437,9 +437,51 @@ int ChangePwd (const wchar_t *lpszVolume, Password *oldPassword, int old_pkcs5,
&& (cryptoInfo->HeaderFlags & TC_HEADER_FLAG_NONSYS_INPLACE_ENC) != 0
&& (cryptoInfo->HeaderFlags & ~TC_HEADER_FLAG_NONSYS_INPLACE_ENC) == 0)
{
PCRYPTO_INFO dummyInfo = NULL;
LARGE_INTEGER hiddenOffset;
nStatus = WriteRandomDataToReservedHeaderAreas (hwndDlg, dev, cryptoInfo, cryptoInfo->VolumeSize.Value, !backupHeader, backupHeader);
if (nStatus != ERR_SUCCESS)
goto error;
// write fake hidden volume header to protect against attacks that use statistical entropy
// analysis to detect presence of hidden volumes
hiddenOffset.QuadPart = backupHeader ? cryptoInfo->VolumeSize.Value + TC_VOLUME_HEADER_GROUP_SIZE + TC_HIDDEN_VOLUME_HEADER_OFFSET: TC_HIDDEN_VOLUME_HEADER_OFFSET;
nStatus = CreateVolumeHeaderInMemory (hwndDlg, FALSE,
buffer,
cryptoInfo->ea,
cryptoInfo->mode,
NULL,
0,
0,
NULL,
&dummyInfo,
cryptoInfo->VolumeSize.Value,
cryptoInfo->VolumeSize.Value,
cryptoInfo->EncryptedAreaStart.Value,
cryptoInfo->EncryptedAreaLength.Value,
truecryptMode? 0 : cryptoInfo->RequiredProgramVersion,
cryptoInfo->HeaderFlags,
cryptoInfo->SectorSize,
wipePass < wipePassCount - 1);
if (nStatus != ERR_SUCCESS)
goto error;
crypto_close (dummyInfo);
if (!SetFilePointerEx ((HANDLE) dev, hiddenOffset, NULL, FILE_BEGIN))
{
nStatus = ERR_OS_ERROR;
goto error;
}
if (!WriteEffectiveVolumeHeader (bDevice, dev, buffer))
{
nStatus = ERR_OS_ERROR;
goto error;
}
}
FlushFileBuffers (dev);

95
src/Common/Volumes.c
View File

@@ -809,7 +809,7 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
unsigned char *p = (unsigned char *) header;
static CRYPTOPP_ALIGN_DATA(16) KEY_INFO keyInfo;
int nUserKeyLen = password->Length;
int nUserKeyLen = password? password->Length : 0;
PCRYPTO_INFO cryptoInfo = crypto_open ();
static char dk[MASTER_KEYDATA_SIZE];
int x;
@@ -844,7 +844,10 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
}
if (!RandgetBytes (hwndDlg, keyInfo.master_keydata, bytesNeeded, TRUE))
{
crypto_close (cryptoInfo);
return ERR_CIPHER_INIT_WEAK_KEY;
}
}
else
{
@@ -853,9 +856,17 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
}
// User key
memcpy (keyInfo.userKey, password->Text, nUserKeyLen);
keyInfo.keyLength = nUserKeyLen;
keyInfo.noIterations = get_pkcs5_iteration_count (pkcs5_prf, pim, FALSE, bBoot);
if (password)
{
memcpy (keyInfo.userKey, password->Text, nUserKeyLen);
keyInfo.keyLength = nUserKeyLen;
keyInfo.noIterations = get_pkcs5_iteration_count (pkcs5_prf, pim, FALSE, bBoot);
}
else
{
keyInfo.keyLength = 0;
keyInfo.noIterations = 0;
}
// User selected encryption algorithm
cryptoInfo->ea = ea;
@@ -871,34 +882,51 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
// Salt for header key derivation
if (!RandgetBytes (hwndDlg, keyInfo.salt, PKCS5_SALT_SIZE, !bWipeMode))
return ERR_CIPHER_INIT_WEAK_KEY;
// PBKDF2 (PKCS5) is used to derive primary header key(s) and secondary header key(s) (XTS) from the password/keyfiles
switch (pkcs5_prf)
{
case SHA512:
derive_key_sha512 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
crypto_close (cryptoInfo);
return ERR_CIPHER_INIT_WEAK_KEY;
}
case SHA256:
derive_key_sha256 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
if (password)
{
// PBKDF2 (PKCS5) is used to derive primary header key(s) and secondary header key(s) (XTS) from the password/keyfiles
switch (pkcs5_prf)
{
case SHA512:
derive_key_sha512 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
case RIPEMD160:
derive_key_ripemd160 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
case SHA256:
derive_key_sha256 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
case WHIRLPOOL:
derive_key_whirlpool (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
case RIPEMD160:
derive_key_ripemd160 (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
default:
// Unknown/wrong ID
TC_THROW_FATAL_EXCEPTION;
case WHIRLPOOL:
derive_key_whirlpool (keyInfo.userKey, keyInfo.keyLength, keyInfo.salt,
PKCS5_SALT_SIZE, keyInfo.noIterations, dk, GetMaxPkcs5OutSize());
break;
default:
// Unknown/wrong ID
crypto_close (cryptoInfo);
TC_THROW_FATAL_EXCEPTION;
}
}
else
{
// generate a random key
if (!RandgetBytes(hwndDlg, dk, GetMaxPkcs5OutSize(), !bWipeMode))
{
crypto_close (cryptoInfo);
return ERR_CIPHER_INIT_WEAK_KEY;
}
}
/* Header setup */
@@ -950,6 +978,7 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
|| sectorSize > TC_MAX_VOLUME_SECTOR_SIZE
|| sectorSize % ENCRYPTION_DATA_UNIT_SIZE != 0)
{
crypto_close (cryptoInfo);
TC_THROW_FATAL_EXCEPTION;
}
@@ -978,11 +1007,17 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
retVal = EAInit (cryptoInfo->ea, dk + primaryKeyOffset, cryptoInfo->ks);
if (retVal != ERR_SUCCESS)
{
crypto_close (cryptoInfo);
return retVal;
}
// Mode of operation
if (!EAInitMode (cryptoInfo))
{
crypto_close (cryptoInfo);
return ERR_OUTOFMEMORY;
}
// Encrypt the entire header (except the salt)
@@ -996,7 +1031,10 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
// Init with the master key(s)
retVal = EAInit (cryptoInfo->ea, keyInfo.master_keydata + primaryKeyOffset, cryptoInfo->ks);
if (retVal != ERR_SUCCESS)
{
crypto_close (cryptoInfo);
return retVal;
}
memcpy (cryptoInfo->master_keydata, keyInfo.master_keydata, MASTER_KEYDATA_SIZE);
@@ -1010,7 +1048,10 @@ int CreateVolumeHeaderInMemory (HWND hwndDlg, BOOL bBoot, char *header, int ea,
// Mode of operation
if (!EAInitMode (cryptoInfo))
{
crypto_close (cryptoInfo);
return ERR_OUTOFMEMORY;
}
#ifdef VOLFORMAT