CVE-2019-1010208 (C, published 2019-07-23T14:15Z)
Description: value: IDRIX, Truecrypt Veracrypt, Truecrypt Prior to 1.23-Hotfix-1 (Veracrypt), all versions (Truecrypt) is affected by: Buffer Overflow. The impact is: Minor information disclosure of kernel stack. The component is: Veracrypt NT Driver (veracrypt.sys). The attack vector is: Locally executed code, IOCTL request to driver. The fixed version is: 1.23-Hotfix-1.
Severity: LOW (CVSS v3 base score: 3.3)
Weakness: CWE-119 \u2014 Improper Restriction of Operations within the Bounds of a Memory Buffer
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.
Repository: https://github.com/veracrypt/VeraCrypt
Files changed:
src/Driver/Ntdriver.c
Commit message: Windows: fix low severity vulnerability in driver that allowed reading 3 bytes of kernel stack memory (with a rare possibility of 25 additional bytes). Reported by Tim Harrison.


Vulnerable code:
			byte readBuffer [TC_SECTOR_SIZE_BIOS];
				// Determine if the first sector contains a portion of the VeraCrypt Boot Loader
				offset.QuadPart = 0;	// MBR

				ntStatus = ZwReadFile (NtFileHandle,
					NULL,
					NULL,
					NULL,
					&IoStatus,
					readBuffer,
					sizeof(readBuffer),
					&offset,
					NULL);

				if (NT_SUCCESS (ntStatus))
					size_t i;
					// Check for dynamic drive
					request->DriveIsDynamic = FALSE;
					if (readBuffer[510] == 0x55 && readBuffer[511] == 0xaa)
						int i;
						for (i = 0; i < 4; ++i)
							if (readBuffer[446 + i * 16 + 4] == PARTITION_LDM)
								request->DriveIsDynamic = TRUE;
								break;
						}
					}
					request->BootLoaderVersion = 0;
					request->Configuration = 0;
					request->UserConfiguration = 0;
					request->CustomUserMessage[0] = 0;
					// Search for the string "VeraCrypt"
					for (i = 0; i < sizeof (readBuffer) - strlen (TC_APP_NAME); ++i)
					{
						if (memcmp (readBuffer + i, TC_APP_NAME, strlen (TC_APP_NAME)) == 0)
						{
							request->BootLoaderVersion = BE16 (*(uint16 *) (readBuffer + TC_BOOT_SECTOR_VERSION_OFFSET));
							request->Configuration = readBuffer[TC_BOOT_SECTOR_CONFIG_OFFSET];

							if (request->BootLoaderVersion != 0 && request->BootLoaderVersion <= VERSION_NUM)
								request->UserConfiguration = readBuffer[TC_BOOT_SECTOR_USER_CONFIG_OFFSET];
								memcpy (request->CustomUserMessage, readBuffer + TC_BOOT_SECTOR_USER_MESSAGE_OFFSET, TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH);
							break;
					Irp->IoStatus.Status = STATUS_SUCCESS;
					Irp->IoStatus.Information = sizeof (*request);
				}
				else
				{
					Irp->IoStatus.Status = ntStatus;
					Irp->IoStatus.Information = 0;

Fixed code:
			size_t devicePathLen = 0;
			// check that request->DevicePath has the expected format "\\Device\\HarddiskXXX\\Partition0"
			if (	!NT_SUCCESS (RtlUnalignedStringCchLengthW (request->DevicePath, TC_MAX_PATH, &devicePathLen))
				||	(devicePathLen < 28) // 28 is the length of "\\Device\\Harddisk0\\Partition0" which is the minimum
				||	(devicePathLen > 30) // 30 is the length of "\\Device\\Harddisk255\\Partition0" which is the maximum
				||	(memcmp (request->DevicePath, L"\\Device\\Harddisk", 16 * sizeof (WCHAR)))
				||	(memcmp (&request->DevicePath[devicePathLen - 11], L"\\Partition0", 11 * sizeof (WCHAR)))
				)
			{
				Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
				Irp->IoStatus.Information = 0;
				break;
			}

				byte *readBuffer = TCalloc (TC_MAX_VOLUME_SECTOR_SIZE);
				if (!readBuffer)
					Irp->IoStatus.Status = STATUS_INSUFFICIENT_RESOURCES;
					Irp->IoStatus.Information = 0;
				}
				else
				{
					// Determine if the first sector contains a portion of the VeraCrypt Boot Loader
					offset.QuadPart = 0;	// MBR
					ntStatus = ZwReadFile (NtFileHandle,
						NULL,
						NULL,
						NULL,
						&IoStatus,
						readBuffer,
						TC_MAX_VOLUME_SECTOR_SIZE,
						&offset,
						NULL);
					if (NT_SUCCESS (ntStatus))
						// check that we could read all needed data
						if (IoStatus.Information >= TC_SECTOR_SIZE_BIOS)
							size_t i;

							// Check for dynamic drive
							request->DriveIsDynamic = FALSE;

							if (readBuffer[510] == 0x55 && readBuffer[511] == 0xaa)
								int i;
								for (i = 0; i < 4; ++i)
								{
									if (readBuffer[446 + i * 16 + 4] == PARTITION_LDM)
									{
										request->DriveIsDynamic = TRUE;
										break;
									}
								}
							request->BootLoaderVersion = 0;
							request->Configuration = 0;
							request->UserConfiguration = 0;
							request->CustomUserMessage[0] = 0;
							// Search for the string "VeraCrypt"
							for (i = 0; i < sizeof (readBuffer) - strlen (TC_APP_NAME); ++i)
								if (memcmp (readBuffer + i, TC_APP_NAME, strlen (TC_APP_NAME)) == 0)
								{
									request->BootLoaderVersion = BE16 (*(uint16 *) (readBuffer + TC_BOOT_SECTOR_VERSION_OFFSET));
									request->Configuration = readBuffer[TC_BOOT_SECTOR_CONFIG_OFFSET];

									if (request->BootLoaderVersion != 0 && request->BootLoaderVersion <= VERSION_NUM)
									{
										request->UserConfiguration = readBuffer[TC_BOOT_SECTOR_USER_CONFIG_OFFSET];
										memcpy (request->CustomUserMessage, readBuffer + TC_BOOT_SECTOR_USER_MESSAGE_OFFSET, TC_BOOT_SECTOR_USER_MESSAGE_MAX_LENGTH);
									}
									break;
								}

							Irp->IoStatus.Status = STATUS_SUCCESS;
							Irp->IoStatus.Information = sizeof (*request);
						}
						else
						{
							Irp->IoStatus.Status = STATUS_INVALID_PARAMETER;
							Irp->IoStatus.Information = 0;
					else
					{
						Irp->IoStatus.Status = ntStatus;
						Irp->IoStatus.Information = 0;
					}
					TCfree (readBuffer);