VeraCrypt
aboutsummaryrefslogtreecommitdiff
path: root/src/Driver/VolumeFilter.c
blob: b3eb8a32d5e3a8a52910f1c82a9825e0dc233e68 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
/*
 Derived from source code of TrueCrypt 7.1a, which is
 Copyright (c) 2008-2012 TrueCrypt Developers Association and which is governed
 by the TrueCrypt License 3.0.

 Modifications and additions to the original source code (contained in this file) 
 and all other portions of this file are Copyright (c) 2013-2015 IDRIX
 and are governed by the Apache License 2.0 the full text of which is
 contained in the file License.txt included in VeraCrypt binary and source
 code distribution packages.
*/

#include "TCdefs.h"
#include "Ntdriver.h"
#include "Ntvol.h"
#include "DriveFilter.h"
#include "VolumeFilter.h"

typedef DriveFilterExtension VolumeFilterExtension;

// Number of times the filter driver answered that an unencrypted volume
// is read-only (or mounted an outer/normal TrueCrypt volume as read only)
uint32 HiddenSysLeakProtectionCount = 0;


NTSTATUS VolumeFilterAddDevice (PDRIVER_OBJECT driverObject, PDEVICE_OBJECT pdo)
{
	VolumeFilterExtension *Extension;
	NTSTATUS status;
	PDEVICE_OBJECT filterDeviceObject = NULL;
	PDEVICE_OBJECT attachedDeviceObject;

	Dump ("VolumeFilterAddDevice pdo=%p\n", pdo);

	attachedDeviceObject = IoGetAttachedDeviceReference (pdo);
	status = IoCreateDevice (driverObject, sizeof (VolumeFilterExtension), NULL, attachedDeviceObject->DeviceType, 0, FALSE, &filterDeviceObject);

	ObDereferenceObject (attachedDeviceObject);

	if (!NT_SUCCESS (status))
	{
		filterDeviceObject = NULL;
		goto err;
	}

	Extension = (VolumeFilterExtension *) filterDeviceObject->DeviceExtension;
	memset (Extension, 0, sizeof (VolumeFilterExtension));

	status = IoAttachDeviceToDeviceStackSafe (filterDeviceObject, pdo, &(Extension->LowerDeviceObject));
	if (status != STATUS_SUCCESS)
	{
		goto err;
	}

	if (!Extension->LowerDeviceObject)
	{
		status = STATUS_DEVICE_REMOVED;
		goto err;
	}
	
	Extension->IsVolumeFilterDevice = TRUE;
	Extension->DeviceObject = filterDeviceObject;
	Extension->Pdo = pdo;

	IoInitializeRemoveLock (&Extension->Queue.RemoveLock, 'LRCV', 0, 0);

	filterDeviceObject->Flags |= Extension->LowerDeviceObject->Flags & (DO_DIRECT_IO | DO_BUFFERED_IO | DO_POWER_PAGABLE);
	filterDeviceObject->Flags &= ~DO_DEVICE_INITIALIZING;

	return status;

err:
	if (filterDeviceObject)
	{
		if (Extension->LowerDeviceObject)
			IoDetachDevice (Extension->LowerDeviceObject);

		IoDeleteDevice (filterDeviceObject);
	}

	return status;
}


static NTSTATUS PassIrp (PDEVICE_OBJECT deviceObject, PIRP irp)
{
	IoSkipCurrentIrpStackLocation (irp);
	return IoCallDriver (deviceObject, irp);
}


static NTSTATUS PassFilteredIrp (PDEVICE_OBJECT deviceObject, PIRP irp, PIO_COMPLETION_ROUTINE completionRoutine, PVOID completionRoutineArg)
{
	IoCopyCurrentIrpStackLocationToNext (irp);

	if (completionRoutine)
		IoSetCompletionRoutine (irp, completionRoutine, completionRoutineArg, TRUE, TRUE, TRUE);

	return IoCallDriver (deviceObject, irp);
}


static NTSTATUS OnDeviceUsageNotificationCompleted (PDEVICE_OBJECT filterDeviceObject, PIRP Irp, VolumeFilterExtension *Extension)
{
	if (Irp->PendingReturned)
		IoMarkIrpPending (Irp);

	if (!(Extension->LowerDeviceObject->Flags & DO_POWER_PAGABLE))
		filterDeviceObject->Flags &= ~DO_POWER_PAGABLE;

	IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
	return STATUS_CONTINUE_COMPLETION;
}


static NTSTATUS OnStartDeviceCompleted (PDEVICE_OBJECT filterDeviceObject, PIRP Irp, VolumeFilterExtension *Extension)
{
	if (Irp->PendingReturned)
		IoMarkIrpPending (Irp);

	if (Extension->LowerDeviceObject->Characteristics & FILE_REMOVABLE_MEDIA)
		filterDeviceObject->Characteristics |= FILE_REMOVABLE_MEDIA;

	IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
	return STATUS_CONTINUE_COMPLETION;
}


static NTSTATUS DispatchControl (PDEVICE_OBJECT DeviceObject, PIRP Irp, VolumeFilterExtension *Extension, PIO_STACK_LOCATION irpSp)
{
	NTSTATUS status = IoAcquireRemoveLock (&Extension->Queue.RemoveLock, Irp);
	if (!NT_SUCCESS (status))
		return TCCompleteIrp (Irp, status, 0);

	if (IsHiddenSystemRunning())
	{
		switch (irpSp->Parameters.DeviceIoControl.IoControlCode)
		{
		case IOCTL_DISK_IS_WRITABLE:
			{
				// All volumes except the system volume must be read-only

				DriveFilterExtension *bootDriveExtension = GetBootDriveFilterExtension();
				STORAGE_DEVICE_NUMBER storageDeviceNumber;

				if (!bootDriveExtension->SystemStorageDeviceNumberValid)
					TC_BUG_CHECK (STATUS_INVALID_PARAMETER);

				status = SendDeviceIoControlRequest (Extension->LowerDeviceObject, IOCTL_STORAGE_GET_DEVICE_NUMBER, NULL, 0, &storageDeviceNumber, sizeof (storageDeviceNumber));

				if (NT_SUCCESS (status) && bootDriveExtension->SystemStorageDeviceNumber == storageDeviceNumber.DeviceNumber)
				{
					PARTITION_INFORMATION_EX partition;
					status = SendDeviceIoControlRequest (Extension->LowerDeviceObject, IOCTL_DISK_GET_PARTITION_INFO_EX, NULL, 0, &partition, sizeof (partition));

					if (NT_SUCCESS (status) && partition.StartingOffset.QuadPart == bootDriveExtension->ConfiguredEncryptedAreaStart)
					{
						IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
						return TCCompleteDiskIrp (Irp, STATUS_SUCCESS, 0);
					}
				}

				IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);

				++HiddenSysLeakProtectionCount;
				return TCCompleteDiskIrp (Irp, STATUS_MEDIA_WRITE_PROTECTED, 0);
			}

		case TC_IOCTL_DISK_IS_WRITABLE:
			Dump ("TC_IOCTL_DISK_IS_WRITABLE pdo=%p\n", Extension->Pdo);

			if (!ProbingHostDeviceForWrite)
				break;

			// Probe the real state of the device as the user is mounting a TrueCrypt volume.

			// Volume filter may be attached to a merged drive+volume PDO. First test if TC_IOCTL_DISK_IS_WRITABLE works for the underlying device.
			status = SendDeviceIoControlRequest (Extension->LowerDeviceObject, TC_IOCTL_DISK_IS_WRITABLE, NULL, 0, NULL, 0);

			if (NT_SUCCESS (status) || status == STATUS_MEDIA_WRITE_PROTECTED)
			{
				IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
				return TCCompleteDiskIrp (Irp, status, 0);
			}

			status = SendDeviceIoControlRequest (Extension->LowerDeviceObject, IOCTL_DISK_IS_WRITABLE, NULL, 0, NULL, 0);

			IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
			return TCCompleteDiskIrp (Irp, status, 0);

		case IOCTL_STORAGE_MANAGE_DATA_SET_ATTRIBUTES:

			// Filter IOCTL_STORAGE_MANAGE_DATA_SET_ATTRIBUTES to enable potential future use of hidden systems on drives that use the trim operation but not wear-leveling (if any appear in future). The documentation forbids users to create hidden volumes/systems on drives that use wear-leveling and consequently also on drives that use trim (as trim is used only by drives that use wear-leveling, as of 2010).

			IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
			return TCCompleteDiskIrp (Irp, STATUS_SUCCESS, 0);
		}
	}

	status = PassIrp (Extension->LowerDeviceObject, Irp);
	IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
	return status;
}


static NTSTATUS DispatchPnp (PDEVICE_OBJECT DeviceObject, PIRP Irp, VolumeFilterExtension *Extension, PIO_STACK_LOCATION irpSp)
{
	NTSTATUS status;

	status = IoAcquireRemoveLock (&Extension->Queue.RemoveLock, Irp);
	if (!NT_SUCCESS (status))
		return TCCompleteIrp (Irp, status, 0);

	switch (irpSp->MinorFunction)
	{
	case IRP_MN_START_DEVICE:
		Dump ("IRP_MN_START_DEVICE volume pdo=%p\n", Extension->Pdo);
		return PassFilteredIrp (Extension->LowerDeviceObject, Irp, OnStartDeviceCompleted, Extension);

	case IRP_MN_DEVICE_USAGE_NOTIFICATION:
		{
			PDEVICE_OBJECT attachedDevice = IoGetAttachedDeviceReference (DeviceObject);

			if (attachedDevice == DeviceObject || (attachedDevice->Flags & DO_POWER_PAGABLE))
				DeviceObject->Flags |= DO_POWER_PAGABLE;

			ObDereferenceObject (attachedDevice);
		}

		return PassFilteredIrp (Extension->LowerDeviceObject, Irp, OnDeviceUsageNotificationCompleted, Extension);


	case IRP_MN_REMOVE_DEVICE:
		Dump ("IRP_MN_REMOVE_DEVICE volume pdo=%p\n", Extension->Pdo);

		IoReleaseRemoveLockAndWait (&Extension->Queue.RemoveLock, Irp);
		status = PassIrp (Extension->LowerDeviceObject, Irp);

		IoDetachDevice (Extension->LowerDeviceObject);

		IoDeleteDevice (DeviceObject);
		return status;

	default:
		status = PassIrp (Extension->LowerDeviceObject, Irp);
		IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
	}

	return status;
}


static NTSTATUS DispatchPower (PDEVICE_OBJECT DeviceObject, PIRP Irp, VolumeFilterExtension *Extension, PIO_STACK_LOCATION irpSp)
{
	NTSTATUS status;
	PoStartNextPowerIrp (Irp);

	status = IoAcquireRemoveLock (&Extension->Queue.RemoveLock, Irp);
	if (!NT_SUCCESS (status))
		return TCCompleteIrp (Irp, status, 0);

	IoSkipCurrentIrpStackLocation (Irp);
	status = PoCallDriver (Extension->LowerDeviceObject, Irp);

	IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
	return status;
}


NTSTATUS VolumeFilterDispatchIrp (PDEVICE_OBJECT DeviceObject, PIRP Irp)
{
	VolumeFilterExtension *Extension = (VolumeFilterExtension *) DeviceObject->DeviceExtension;
	PIO_STACK_LOCATION irpSp = IoGetCurrentIrpStackLocation (Irp);
	NTSTATUS status;

	ASSERT (!Extension->bRootDevice && Extension->IsVolumeFilterDevice);

	switch (irpSp->MajorFunction)
	{
	case IRP_MJ_DEVICE_CONTROL:
		return DispatchControl (DeviceObject, Irp, Extension, irpSp);

	case IRP_MJ_PNP:
		return DispatchPnp (DeviceObject, Irp, Extension, irpSp);

	case IRP_MJ_POWER:
		return DispatchPower (DeviceObject, Irp, Extension, irpSp);

	default:
		status = IoAcquireRemoveLock (&Extension->Queue.RemoveLock, Irp);
		if (!NT_SUCCESS (status))
			return TCCompleteIrp (Irp, status, 0);

		status = PassIrp (Extension->LowerDeviceObject, Irp);

		IoReleaseRemoveLock (&Extension->Queue.RemoveLock, Irp);
		return status;
	}
}