VeraCrypt
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authorMounir IDRASSI <mounir.idrassi@idrix.fr>2015-10-05 01:22:11 (GMT)
committerMounir IDRASSI <mounir.idrassi@idrix.fr>2015-10-05 02:31:17 (GMT)
commitc94f8c9b63edc756aa05ec85ed8da84ab799205c (patch)
tree63607ad8dc4f41d349e14310e0ae61d57ff062c3
parentea451c72414ea8a14e34fb5da3eaf18c05f9b5dd (diff)
downloadVeraCrypt-c94f8c9b63edc756aa05ec85ed8da84ab799205c.zip
VeraCrypt-c94f8c9b63edc756aa05ec85ed8da84ab799205c.tar.gz
Windows Driver: Modify fix for CVE-2015-7358 to solve side effects on Windows mount manager while still making it hard to abuse drive letter handling.
-rw-r--r--src/Common/Apidrvr.h3
-rw-r--r--src/Driver/Ntdriver.c47
-rw-r--r--src/Driver/Ntdriver.h9
3 files changed, 43 insertions, 16 deletions
diff --git a/src/Common/Apidrvr.h b/src/Common/Apidrvr.h
index 4fc1576..79cf237 100644
--- a/src/Common/Apidrvr.h
+++ b/src/Common/Apidrvr.h
@@ -322,7 +322,8 @@ typedef struct
#define NT_MOUNT_PREFIX DRIVER_STR("\\Device\\VeraCryptVolume")
#define NT_ROOT_PREFIX DRIVER_STR("\\Device\\VeraCrypt")
-#define DOS_MOUNT_PREFIX DRIVER_STR("\\GLOBAL??\\") // Explicitely use Global MS-DOS device names to avoid security issues
+#define DOS_MOUNT_PREFIX_DEFAULT DRIVER_STR("\\DosDevices\\")
+#define DOS_MOUNT_PREFIX_GLOBAL DRIVER_STR("\\GLOBAL??\\") // Use Global MS-DOS device names for sanity checks on drive letters
#define DOS_ROOT_PREFIX DRIVER_STR("\\DosDevices\\VeraCrypt")
#define WIN32_ROOT_PREFIX DRIVER_STR("\\\\.\\VeraCrypt")
diff --git a/src/Driver/Ntdriver.c b/src/Driver/Ntdriver.c
index a494c68..2a82c5a 100644
--- a/src/Driver/Ntdriver.c
+++ b/src/Driver/Ntdriver.c
@@ -586,7 +586,7 @@ NTSTATUS ProcessVolumeDeviceControlIrp (PDEVICE_OBJECT DeviceObject, PEXTENSION
break;
}
- TCGetDosNameFromNumber (ntName, sizeof(ntName),Extension->nDosDriveNo);
+ TCGetDosNameFromNumber (ntName, sizeof(ntName),Extension->nDosDriveNo, DeviceNamespaceDefault);
RtlInitUnicodeString (&ntUnicodeString, ntName);
outLength = FIELD_OFFSET(MOUNTDEV_SUGGESTED_LINK_NAME,Name) + ntUnicodeString.Length;
@@ -1965,14 +1965,23 @@ void TCGetNTNameFromNumber (LPWSTR ntname, int cbNtName, int nDriveNo)
RtlStringCbCatW (ntname, cbNtName, tmp);
}
-void TCGetDosNameFromNumber (LPWSTR dosname,int cbDosName, int nDriveNo)
+void TCGetDosNameFromNumber (LPWSTR dosname,int cbDosName, int nDriveNo, DeviceNamespaceType namespaceType)
{
WCHAR tmp[3] =
{0, ':', 0};
int j = nDriveNo + (WCHAR) 'A';
tmp[0] = (short) j;
- RtlStringCbCopyW (dosname, cbDosName, (LPWSTR) DOS_MOUNT_PREFIX);
+
+ if (DeviceNamespaceGlobal == namespaceType)
+ {
+ RtlStringCbCopyW (dosname, cbDosName, (LPWSTR) DOS_MOUNT_PREFIX_GLOBAL);
+ }
+ else
+ {
+ RtlStringCbCopyW (dosname, cbDosName, (LPWSTR) DOS_MOUNT_PREFIX_DEFAULT);
+ }
+
RtlStringCbCatW (dosname, cbDosName, tmp);
}
@@ -2538,7 +2547,7 @@ NTSTATUS CreateDriveLink (int nDosDriveNo)
NTSTATUS ntStatus;
TCGetNTNameFromNumber (dev, sizeof(dev),nDosDriveNo);
- TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo);
+ TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo, DeviceNamespaceDefault);
RtlInitUnicodeString (&deviceName, dev);
RtlInitUnicodeString (&symLink, link);
@@ -2555,7 +2564,7 @@ NTSTATUS RemoveDriveLink (int nDosDriveNo)
UNICODE_STRING symLink;
NTSTATUS ntStatus;
- TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo);
+ TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo, DeviceNamespaceDefault);
RtlInitUnicodeString (&symLink, link);
ntStatus = IoDeleteSymbolicLink (&symLink);
@@ -2580,7 +2589,7 @@ NTSTATUS MountManagerMount (MOUNT_STRUCT *mount)
in, (ULONG) (sizeof (in->DeviceNameLength) + wcslen (arrVolume) * 2), 0, 0);
memset (buf, 0, sizeof buf);
- TCGetDosNameFromNumber ((PWSTR) &point[1], sizeof(buf) - sizeof(MOUNTMGR_CREATE_POINT_INPUT),mount->nDosDriveNo);
+ TCGetDosNameFromNumber ((PWSTR) &point[1], sizeof(buf) - sizeof(MOUNTMGR_CREATE_POINT_INPUT),mount->nDosDriveNo, DeviceNamespaceDefault);
point->SymbolicLinkNameOffset = sizeof (MOUNTMGR_CREATE_POINT_INPUT);
point->SymbolicLinkNameLength = (USHORT) wcslen ((PWSTR) &point[1]) * 2;
@@ -2590,7 +2599,7 @@ NTSTATUS MountManagerMount (MOUNT_STRUCT *mount)
point->DeviceNameLength = (USHORT) wcslen ((PWSTR) (buf + point->DeviceNameOffset)) * 2;
ntStatus = TCDeviceIoControl (MOUNTMGR_DEVICE_NAME, IOCTL_MOUNTMGR_CREATE_POINT, point,
- point->DeviceNameOffset + point->DeviceNameLength, 0, 0);
+ point->DeviceNameOffset + point->DeviceNameLength, 0, 0);
return ntStatus;
}
@@ -2604,7 +2613,7 @@ NTSTATUS MountManagerUnmount (int nDosDriveNo)
memset (buf, 0, sizeof buf);
- TCGetDosNameFromNumber ((PWSTR) &in[1], sizeof(buf) - sizeof(MOUNTMGR_MOUNT_POINT),nDosDriveNo);
+ TCGetDosNameFromNumber ((PWSTR) &in[1], sizeof(buf) - sizeof(MOUNTMGR_MOUNT_POINT),nDosDriveNo, DeviceNamespaceDefault);
// Only symbolic link can be deleted with IOCTL_MOUNTMGR_DELETE_POINTS. If any other entry is specified, the mount manager will ignore subsequent IOCTL_MOUNTMGR_VOLUME_ARRIVAL_NOTIFICATION for the same volume ID.
in->SymbolicLinkNameOffset = sizeof (MOUNTMGR_MOUNT_POINT);
@@ -2622,10 +2631,13 @@ NTSTATUS MountManagerUnmount (int nDosDriveNo)
NTSTATUS MountDevice (PDEVICE_OBJECT DeviceObject, MOUNT_STRUCT *mount)
{
PDEVICE_OBJECT NewDeviceObject;
- NTSTATUS ntStatus;
+ NTSTATUS ntStatus;
// Make sure the user is asking for a reasonable nDosDriveNo
- if (mount->nDosDriveNo >= 0 && mount->nDosDriveNo <= 25 && IsDriveLetterAvailable (mount->nDosDriveNo))
+ if (mount->nDosDriveNo >= 0 && mount->nDosDriveNo <= 25
+ && IsDriveLetterAvailable (mount->nDosDriveNo, DeviceNamespaceDefault) // drive letter must not exist both locally and globally
+ && IsDriveLetterAvailable (mount->nDosDriveNo, DeviceNamespaceGlobal)
+ )
{
Dump ("Mount request looks valid\n");
}
@@ -2716,6 +2728,16 @@ NTSTATUS MountDevice (PDEVICE_OBJECT DeviceObject, MOUNT_STRUCT *mount)
NewExtension->UniqueVolumeId = LastUniqueVolumeId++;
+ // check again that the drive letter is available globally and locally
+ if ( !IsDriveLetterAvailable (mount->nDosDriveNo, DeviceNamespaceDefault)
+ || !IsDriveLetterAvailable (mount->nDosDriveNo, DeviceNamespaceGlobal)
+ )
+ {
+ TCDeleteDeviceObject (NewDeviceObject, NewExtension);
+ mount->nReturnCode = ERR_DRIVE_NOT_FOUND;
+ return ERR_DRIVE_NOT_FOUND;
+ }
+
if (mount->bMountManager)
MountManagerMount (mount);
@@ -3049,8 +3071,7 @@ BOOL UserCanAccessDriveDevice ()
return IsAccessibleByUser (&name, FALSE);
}
-
-BOOL IsDriveLetterAvailable (int nDosDriveNo)
+BOOL IsDriveLetterAvailable (int nDosDriveNo, DeviceNamespaceType namespaceType)
{
OBJECT_ATTRIBUTES objectAttributes;
UNICODE_STRING objectName;
@@ -3058,7 +3079,7 @@ BOOL IsDriveLetterAvailable (int nDosDriveNo)
HANDLE handle;
NTSTATUS ntStatus;
- TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo);
+ TCGetDosNameFromNumber (link, sizeof(link),nDosDriveNo, namespaceType);
RtlInitUnicodeString (&objectName, link);
InitializeObjectAttributes (&objectAttributes, &objectName, OBJ_KERNEL_HANDLE | OBJ_CASE_INSENSITIVE, NULL, NULL);
diff --git a/src/Driver/Ntdriver.h b/src/Driver/Ntdriver.h
index 8da75c6..07ae5f8 100644
--- a/src/Driver/Ntdriver.h
+++ b/src/Driver/Ntdriver.h
@@ -101,6 +101,11 @@ typedef enum
ValidateInputOutput
} ValidateIOBufferSizeType;
+typedef enum
+{
+ DeviceNamespaceDefault,
+ DeviceNamespaceGlobal,
+} DeviceNamespaceType;
extern PDRIVER_OBJECT TCDriverObject;
extern PDEVICE_OBJECT RootDeviceObject;
@@ -133,7 +138,7 @@ void TCStopVolumeThread (PDEVICE_OBJECT DeviceObject, PEXTENSION Extension);
VOID VolumeThreadProc (PVOID Context);
void TCSleep (int milliSeconds);
void TCGetNTNameFromNumber (LPWSTR ntname, int cbNtName, int nDriveNo);
-void TCGetDosNameFromNumber (LPWSTR dosname, int cbDosName, int nDriveNo);
+void TCGetDosNameFromNumber (LPWSTR dosname, int cbDosName, int nDriveNo, DeviceNamespaceType namespaceType);
LPWSTR TCTranslateCode (ULONG ulCode);
void TCDeleteDeviceObject (PDEVICE_OBJECT DeviceObject, PEXTENSION Extension);
VOID TCUnloadDriver (PDRIVER_OBJECT DriverObject);
@@ -161,7 +166,7 @@ BOOL UserCanAccessDriveDevice ();
size_t GetCpuCount ();
void EnsureNullTerminatedString (wchar_t *str, size_t maxSizeInBytes);
void *AllocateMemoryWithTimeout (size_t size, int retryDelay, int timeout);
-BOOL IsDriveLetterAvailable (int nDosDriveNo);
+BOOL IsDriveLetterAvailable (int nDosDriveNo, DeviceNamespaceType namespaceType);
NTSTATUS TCReadRegistryKey (PUNICODE_STRING keyPath, wchar_t *keyValueName, PKEY_VALUE_PARTIAL_INFORMATION *keyData);
NTSTATUS TCWriteRegistryKey (PUNICODE_STRING keyPath, wchar_t *keyValueName, ULONG keyValueType, void *valueData, ULONG valueSize);
BOOL IsVolumeClassFilterRegistered ();