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authorMounir IDRASSI <mounir.idrassi@idrix.fr>2015-07-28 22:09:14 (GMT)
committerMounir IDRASSI <mounir.idrassi@idrix.fr>2015-07-28 22:33:10 (GMT)
commit6ca598f8418a1ab12ff7353c534d610b4dbac943 (patch)
treec7c58d7fbd700e3ab4fef078a58c83c2430d847d /src/Driver/DriveFilter.c
parent69a8ad5bbaa1be2b3a6548c2b3f930d3aa4379e3 (diff)
downloadVeraCrypt-6ca598f8418a1ab12ff7353c534d610b4dbac943.zip
VeraCrypt-6ca598f8418a1ab12ff7353c534d610b4dbac943.tar.gz
Windows: Implement Evil-Maid-Attack detection mechanism. Write the correct bootloader when changing the system encryption password: this enables to recover if an attack is detected.
Diffstat (limited to 'src/Driver/DriveFilter.c')
-rw-r--r--src/Driver/DriveFilter.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/src/Driver/DriveFilter.c b/src/Driver/DriveFilter.c
index d3bc2dc..4b9117e 100644
--- a/src/Driver/DriveFilter.c
+++ b/src/Driver/DriveFilter.c
@@ -35,6 +35,7 @@ static KMUTEX MountMutex;
static volatile BOOL BootDriveFound = FALSE;
static DriveFilterExtension *BootDriveFilterExtension = NULL;
static LARGE_INTEGER BootDriveLength;
+static byte BootLoaderFingerprint[WHIRLPOOL_DIGESTSIZE + SHA512_DIGESTSIZE];
static BOOL CrashDumpEnabled = FALSE;
static BOOL HibernationEnabled = FALSE;
@@ -121,6 +122,9 @@ NTSTATUS LoadBootArguments ()
if (CacheBootPassword && BootArgs.BootPassword.Length > 0)
AddPasswordToCache (&BootArgs.BootPassword);
+ // clear fingerprint
+ burn (BootLoaderFingerprint, sizeof (BootLoaderFingerprint));
+
status = STATUS_SUCCESS;
}
}
@@ -216,6 +220,77 @@ static void DismountDrive (DriveFilterExtension *Extension, BOOL stopIoQueue)
Extension->DriveMounted = FALSE;
}
+static void ComputeBootLoaderFingerprint(PDEVICE_OBJECT LowerDeviceObject, byte* ioBuffer /* ioBuffer must be at least 512 bytes long */)
+{
+ NTSTATUS status;
+ LARGE_INTEGER offset;
+ WHIRLPOOL_CTX whirlpool;
+ sha512_ctx sha2;
+ ULONG bytesToRead, remainingBytes, bootloaderTotalSize = TC_BOOT_LOADER_AREA_SIZE - TC_BOOT_ENCRYPTION_VOLUME_HEADER_SIZE;
+
+ // clear fingerprint
+ burn (BootLoaderFingerprint, sizeof (BootLoaderFingerprint));
+
+ // compute Whirlpool+SHA512 fingerprint of bootloader including MBR
+ // we skip user configuration fields:
+ // TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_OFFSET = 402
+ // => TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_SIZE = 4
+ // TC_BOOT_SECTOR_USER_MESSAGE_OFFSET = 406
+ // => TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH = 24
+ // TC_BOOT_SECTOR_USER_CONFIG_OFFSET = 438
+ //
+ // we have: TC_BOOT_SECTOR_USER_MESSAGE_OFFSET = TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_OFFSET + TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_SIZE
+
+ WHIRLPOOL_init (&whirlpool);
+ sha512_begin (&sha2);
+ // read the first 512 bytes
+ offset.QuadPart = 0;
+
+ status = TCReadDevice (LowerDeviceObject, ioBuffer, offset, TC_SECTOR_SIZE_BIOS);
+ if (NT_SUCCESS (status))
+ {
+ WHIRLPOOL_add (ioBuffer, TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_OFFSET * 8, &whirlpool);
+ WHIRLPOOL_add (ioBuffer + TC_BOOT_SECTOR_USER_MESSAGE_OFFSET + TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH, (TC_BOOT_SECTOR_USER_CONFIG_OFFSET - (TC_BOOT_SECTOR_USER_MESSAGE_OFFSET + TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH)) * 8, &whirlpool);
+ WHIRLPOOL_add (ioBuffer + TC_BOOT_SECTOR_USER_CONFIG_OFFSET + 1, (TC_MAX_MBR_BOOT_CODE_SIZE - (TC_BOOT_SECTOR_USER_CONFIG_OFFSET + 1)) * 8, &whirlpool);
+
+ sha512_hash (ioBuffer, TC_BOOT_SECTOR_OUTER_VOLUME_BAK_HEADER_CRC_OFFSET, &sha2);
+ sha512_hash (ioBuffer + TC_BOOT_SECTOR_USER_MESSAGE_OFFSET + TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH, (TC_BOOT_SECTOR_USER_CONFIG_OFFSET - (TC_BOOT_SECTOR_USER_MESSAGE_OFFSET + TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH)), &sha2);
+ sha512_hash (ioBuffer + TC_BOOT_SECTOR_USER_CONFIG_OFFSET + 1, (TC_MAX_MBR_BOOT_CODE_SIZE - (TC_BOOT_SECTOR_USER_CONFIG_OFFSET + 1)), &sha2);
+
+ // we has the reste of the bootloader, 512 bytes at a time
+ offset.QuadPart = TC_SECTOR_SIZE_BIOS;
+ remainingBytes = bootloaderTotalSize - TC_SECTOR_SIZE_BIOS;
+
+ while (NT_SUCCESS (status) && (remainingBytes > 0))
+ {
+ bytesToRead = (remainingBytes >= TC_SECTOR_SIZE_BIOS)? TC_SECTOR_SIZE_BIOS : remainingBytes;
+ status = TCReadDevice (LowerDeviceObject, ioBuffer, offset, bytesToRead);
+ if (NT_SUCCESS (status))
+ {
+ remainingBytes -= bytesToRead;
+ offset.QuadPart += bytesToRead;
+ WHIRLPOOL_add (ioBuffer, bytesToRead * 8, &whirlpool);
+ sha512_hash (ioBuffer, bytesToRead, &sha2);
+ }
+ else
+ {
+ Dump ("TCReadDevice error %x during ComputeBootLoaderFingerprint call\n", status);
+ break;
+ }
+ }
+
+ if (NT_SUCCESS (status))
+ {
+ WHIRLPOOL_finalize (&whirlpool, BootLoaderFingerprint);
+ sha512_end (&BootLoaderFingerprint [WHIRLPOOL_DIGESTSIZE], &sha2);
+ }
+ }
+ else
+ {
+ Dump ("TCReadDevice error %x during ComputeBootLoaderFingerprint call\n", status);
+ }
+}
+
static NTSTATUS MountDrive (DriveFilterExtension *Extension, Password *password, uint32 *headerSaltCrc32)
{
@@ -302,6 +377,9 @@ static NTSTATUS MountDrive (DriveFilterExtension *Extension, Password *password,
// Header decrypted
status = STATUS_SUCCESS;
Dump ("Header decrypted\n");
+
+ // calculate Fingerprint
+ ComputeBootLoaderFingerprint (Extension->LowerDeviceObject, header);
if (Extension->Queue.CryptoInfo->hiddenVolume)
{
@@ -807,6 +885,7 @@ void ReopenBootVolumeHeader (PIRP irp, PIO_STACK_LOCATION irpSp)
if (ReadVolumeHeader (!BootDriveFilterExtension->HiddenSystem, header, &request->VolumePassword, request->pkcs5_prf, request->pim, FALSE, NULL, BootDriveFilterExtension->HeaderCryptoInfo) == 0)
{
Dump ("Header reopened\n");
+ ComputeBootLoaderFingerprint (BootDriveFilterExtension->LowerDeviceObject, header);
BootDriveFilterExtension->Queue.CryptoInfo->header_creation_time = BootDriveFilterExtension->HeaderCryptoInfo->header_creation_time;
BootDriveFilterExtension->Queue.CryptoInfo->pkcs5 = BootDriveFilterExtension->HeaderCryptoInfo->pkcs5;
@@ -1681,6 +1760,24 @@ void GetBootLoaderVersion (PIRP irp, PIO_STACK_LOCATION irpSp)
}
}
+void GetBootLoaderFingerprint (PIRP irp, PIO_STACK_LOCATION irpSp)
+{
+ if (ValidateIOBufferSize (irp, sizeof (BootLoaderFingerprintRequest), ValidateOutput))
+ {
+ if (BootArgsValid)
+ {
+ BootLoaderFingerprintRequest *bootLoaderFingerprint = (BootLoaderFingerprintRequest *) irp->AssociatedIrp.SystemBuffer;
+ memcpy (bootLoaderFingerprint->Fingerprint, BootLoaderFingerprint, sizeof (BootLoaderFingerprint));
+ irp->IoStatus.Information = sizeof (BootLoaderFingerprintRequest);
+ irp->IoStatus.Status = STATUS_SUCCESS;
+ }
+ else
+ {
+ irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
+ irp->IoStatus.Information = 0;
+ }
+ }
+}
void GetBootEncryptionAlgorithmName (PIRP irp, PIO_STACK_LOCATION irpSp)
{