winfsp/src/ku/uuid5.c
2019-09-04 13:45:53 -07:00

135 lines
4.4 KiB
C

/**
* @file dll/uuid5.c
*
* @copyright 2015-2019 Bill Zissimopoulos
*/
/*
* This file is part of WinFsp.
*
* You can redistribute it and/or modify it under the terms of the GNU
* General Public License version 3 as published by the Free Software
* Foundation.
*
* Licensees holding a valid commercial license may use this software
* in accordance with the commercial license agreement provided in
* conjunction with the software. The terms and conditions of any such
* commercial license agreement shall govern, supersede, and render
* ineffective any application of the GPLv3 license to this software,
* notwithstanding of any reference thereto in the software or
* associated repository.
*/
#include <ku/library.h>
#include <bcrypt.h>
/*
* This module is used to create UUID v5 identifiers. UUID v5 identifiers
* are effectively SHA1 hashes that are modified to fit within the UUID
* format. The resulting identifiers use version 5 and variant 2. The hash
* is taken over the concatenation of a namespace ID and a name; the namespace
* ID is another UUID and the name can be any string of bytes ("octets").
*
* For details see RFC 4122: https://tools.ietf.org/html/rfc4122
*/
NTSTATUS FspUuid5Make(const UUID *Namespace, const VOID *Buffer, ULONG Size, UUID *Uuid)
{
BCRYPT_ALG_HANDLE ProvHandle = 0;
BCRYPT_HASH_HANDLE HashHandle = 0;
UINT8 Temp[20];
NTSTATUS Result;
/*
* Windows UUID's are encoded in little-endian format. RFC 4122 specifies that for
* UUID v5 computation, UUID's must be converted to/from big-endian.
*
* Note that Windows is always little-endian:
* https://community.osr.com/discussion/comment/146810/#Comment_146810
*/
/* copy Namespace to local buffer in network byte order (big-endian) */
Temp[ 0] = ((PUINT8)Namespace)[ 3];
Temp[ 1] = ((PUINT8)Namespace)[ 2];
Temp[ 2] = ((PUINT8)Namespace)[ 1];
Temp[ 3] = ((PUINT8)Namespace)[ 0];
Temp[ 4] = ((PUINT8)Namespace)[ 5];
Temp[ 5] = ((PUINT8)Namespace)[ 4];
Temp[ 6] = ((PUINT8)Namespace)[ 7];
Temp[ 7] = ((PUINT8)Namespace)[ 6];
Temp[ 8] = ((PUINT8)Namespace)[ 8];
Temp[ 9] = ((PUINT8)Namespace)[ 9];
Temp[10] = ((PUINT8)Namespace)[10];
Temp[11] = ((PUINT8)Namespace)[11];
Temp[12] = ((PUINT8)Namespace)[12];
Temp[13] = ((PUINT8)Namespace)[13];
Temp[14] = ((PUINT8)Namespace)[14];
Temp[15] = ((PUINT8)Namespace)[15];
/*
* Unfortunately we cannot reuse the hashing object, because BCRYPT_HASH_REUSABLE_FLAG
* is available in Windows 8 and later. (WinFsp currently supports Windows 7 or later).
*/
Result = BCryptOpenAlgorithmProvider(&ProvHandle, BCRYPT_SHA1_ALGORITHM, 0, 0);
if (!NT_SUCCESS(Result))
goto exit;
Result = BCryptCreateHash(ProvHandle, &HashHandle, 0, 0, 0, 0, 0);
if (!NT_SUCCESS(Result))
goto exit;
Result = BCryptHashData(HashHandle, (PVOID)Temp, 16, 0);
if (!NT_SUCCESS(Result))
goto exit;
Result = BCryptHashData(HashHandle, (PVOID)Buffer, Size, 0);
if (!NT_SUCCESS(Result))
goto exit;
Result = BCryptFinishHash(HashHandle, Temp, 20, 0);
if (!NT_SUCCESS(Result))
goto exit;
/* copy local buffer to Uuid in host byte order (little-endian) */
((PUINT8)Uuid)[ 0] = Temp[ 3];
((PUINT8)Uuid)[ 1] = Temp[ 2];
((PUINT8)Uuid)[ 2] = Temp[ 1];
((PUINT8)Uuid)[ 3] = Temp[ 0];
((PUINT8)Uuid)[ 4] = Temp[ 5];
((PUINT8)Uuid)[ 5] = Temp[ 4];
((PUINT8)Uuid)[ 6] = Temp[ 7];
((PUINT8)Uuid)[ 7] = Temp[ 6];
((PUINT8)Uuid)[ 8] = Temp[ 8];
((PUINT8)Uuid)[ 9] = Temp[ 9];
((PUINT8)Uuid)[10] = Temp[10];
((PUINT8)Uuid)[11] = Temp[11];
((PUINT8)Uuid)[12] = Temp[12];
((PUINT8)Uuid)[13] = Temp[13];
((PUINT8)Uuid)[14] = Temp[14];
((PUINT8)Uuid)[15] = Temp[15];
/* [RFC 4122 Section 4.3]
* Set the four most significant bits (bits 12 through 15) of the
* time_hi_and_version field to the appropriate 4-bit version number
* from Section 4.1.3.
*/
Uuid->Data3 = (5 << 12) | (Uuid->Data3 & 0x0fff);
/* [RFC 4122 Section 4.3]
* Set the two most significant bits (bits 6 and 7) of the
* clock_seq_hi_and_reserved to zero and one, respectively.
*/
Uuid->Data4[0] = (2 << 6) | (Uuid->Data4[0] & 0x3f);
Result = STATUS_SUCCESS;
exit:
if (0 != HashHandle)
BCryptDestroyHash(HashHandle);
if (0 != ProvHandle)
BCryptCloseAlgorithmProvider(ProvHandle, 0);
return Result;
}