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/* $Id: alt-md2.cpp $ */
/** @file
* IPRT - Message-Digest Algorithm 2, Alternative Implementation.
*/
/*
* Copyright (C) 2009-2023 Oracle and/or its affiliates.
*
* This file is part of VirtualBox base platform packages, as
* available from https://www.virtualbox.org.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation, in version 3 of the
* License.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <https://www.gnu.org/licenses>.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
* in the VirtualBox distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*
* SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
*/
/*********************************************************************************************************************************
* Defined Constants And Macros *
*********************************************************************************************************************************/
/** The MD2 block size. */
#define RTMD2_BLOCK_SIZE 16
/** The offset of the buffer into RTMD2ALTPRIVATECTX::abStateX. */
#define RTMD2_BUF_OFF RTMD2_BLOCK_SIZE
/*********************************************************************************************************************************
* Header Files *
*********************************************************************************************************************************/
#include "internal/iprt.h"
#include <iprt/types.h>
/** Our private context structure. */
typedef struct RTMD2ALTPRIVATECTX
{
/** The state (X).
* The staging buffer starts byte 16. */
uint8_t abStateX[RTMD2_BLOCK_SIZE * 3];
/** The checksum. */
uint8_t abChecksum[RTMD2_BLOCK_SIZE];
/** The number of buffered bytes. */
uint8_t cbBuffer;
} RTMD2ALTPRIVATECTX;
#define RT_MD2_PRIVATE_ALT_CONTEXT
#include <iprt/md2.h>
#include <iprt/assert.h>
#include <iprt/string.h>
AssertCompile(RT_SIZEOFMEMB(RTMD2CONTEXT, abPadding) >= RT_SIZEOFMEMB(RTMD2CONTEXT, AltPrivate));
/*********************************************************************************************************************************
* Global Variables *
*********************************************************************************************************************************/
/** PI substitation used by MD2. */
static uint8_t const g_PiSubst[256] =
{
41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, 19,
98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, 76, 130, 202,
30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24, 138, 23, 229, 18,
190, 78, 196, 214, 218, 158, 222, 73, 160, 251, 245, 142, 187, 47, 238, 122,
169, 104, 121, 145, 21, 178, 7, 63, 148, 194, 16, 137, 11, 34, 95, 33,
128, 127, 93, 154, 90, 144, 50, 39, 53, 62, 204, 231, 191, 247, 151, 3,
255, 25, 48, 179, 72, 165, 181, 209, 215, 94, 146, 42, 172, 86, 170, 198,
79, 184, 56, 210, 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241,
69, 157, 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2,
27, 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197, 234, 38,
44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65, 129, 77, 82,
106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123, 8, 12, 189, 177, 74,
120, 136, 149, 139, 227, 99, 232, 109, 233, 203, 213, 254, 59, 0, 29, 57,
242, 239, 183, 14, 102, 88, 208, 228, 166, 119, 114, 248, 235, 117, 75, 10,
49, 68, 80, 180, 143, 237, 31, 26, 219, 153, 141, 51, 159, 17, 131, 20,
};
RTDECL(void) RTMd2Init(PRTMD2CONTEXT pCtx)
{
pCtx->AltPrivate.cbBuffer = 0;
RT_ZERO(pCtx->AltPrivate.abStateX);
RT_ZERO(pCtx->AltPrivate.abChecksum);
}
RT_EXPORT_SYMBOL(RTMd2Init);
/**
* Initializes the processing of a whole block directly from the input buffer.
*
* This will update the checksum as well as initializing abStateX.
*
* @param pCtx The MD2 context.
* @param pbBlock The block.
*/
DECLINLINE(void) rtMd2BlockInit(PRTMD2CONTEXT pCtx, const uint8_t *pbBlock)
{
uint8_t bL = pCtx->AltPrivate.abChecksum[15];
for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
{
uint8_t bIn = pbBlock[j];
pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE] = bIn;
pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
bL = pCtx->AltPrivate.abChecksum[j] ^= g_PiSubst[bIn ^ bL];
}
}
/**
* Special version of rtMd2BlockInit that does not update the checksum.
*
* This is used in the final round when adding the checksum to the calculation.
*
* @param pCtx The MD2 context.
* @param pbBlock The block (i.e. the checksum).
*/
DECLINLINE(void) rtMd2BlockInitNoChecksum(PRTMD2CONTEXT pCtx, const uint8_t *pbBlock)
{
for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
{
uint8_t bIn = pbBlock[j];
pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE] = bIn;
pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
}
}
/**
* Initalizes the abStateX from a full buffer and update the checksum.
*
* The buffer is part of the abStateX structure (bytes 16 thru 31), so this
* is a somewhat reduced version of rtMd2BlockInit.
*
* @param pCtx The MD2 context.
*/
DECLINLINE(void) rtMd2BlockInitBuffered(PRTMD2CONTEXT pCtx)
{
uint8_t bL = pCtx->AltPrivate.abChecksum[15];
for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
{
uint8_t bIn = pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE];
pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
bL = pCtx->AltPrivate.abChecksum[j] ^= g_PiSubst[bIn ^ bL];
}
}
/**
* Process the current block.
*
* Requires one of the rtMd2BlockInit functions to be called first.
*
* @param pCtx The MD2 context.
*/
DECLINLINE(void) rtMd2BlockProcess(PRTMD2CONTEXT pCtx)
{
uint8_t bT = 0;
for (unsigned j = 0; j < 18; j++) /* 18 rounds */
{
for (unsigned k = 0; k < RTMD2_BLOCK_SIZE * 3; k++)
pCtx->AltPrivate.abStateX[k] = bT = pCtx->AltPrivate.abStateX[k] ^ g_PiSubst[bT];
bT += (uint8_t)j;
}
}
RTDECL(void) RTMd2Update(PRTMD2CONTEXT pCtx, const void *pvBuf, size_t cbBuf)
{
Assert(pCtx->AltPrivate.cbBuffer < RTMD2_BLOCK_SIZE);
uint8_t const *pbBuf = (uint8_t const *)pvBuf;
/*
* Deal with buffered bytes first.
*/
if (pCtx->AltPrivate.cbBuffer)
{
uint8_t cbMissing = RTMD2_BLOCK_SIZE - pCtx->AltPrivate.cbBuffer;
if (cbBuf >= cbMissing)
{
memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], pbBuf, cbMissing);
pbBuf += cbMissing;
cbBuf -= cbMissing;
rtMd2BlockInitBuffered(pCtx);
rtMd2BlockProcess(pCtx);
pCtx->AltPrivate.cbBuffer = 0;
}
else
{
memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], pbBuf, cbBuf);
pCtx->AltPrivate.cbBuffer += (uint8_t)cbBuf;
return;
}
}
/*
* Process full blocks directly from the input buffer.
*/
while (cbBuf >= RTMD2_BLOCK_SIZE)
{
rtMd2BlockInit(pCtx, pbBuf);
rtMd2BlockProcess(pCtx);
pbBuf += RTMD2_BLOCK_SIZE;
cbBuf -= RTMD2_BLOCK_SIZE;
}
/*
* Stash any remaining bytes into the context buffer.
*/
if (cbBuf > 0)
{
memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF], pbBuf, cbBuf);
pCtx->AltPrivate.cbBuffer = (uint8_t)cbBuf;
}
}
RT_EXPORT_SYMBOL(RTMd2Update);
RTDECL(void) RTMd2Final(PRTMD2CONTEXT pCtx, uint8_t pabDigest[RTMD2_HASH_SIZE])
{
Assert(pCtx->AltPrivate.cbBuffer < RTMD2_BLOCK_SIZE);
/*
* Pad the message to a multiple of 16 bytes. This is done even if the
* message already is a multiple of 16.
*/
unsigned cbPad = RTMD2_BLOCK_SIZE - pCtx->AltPrivate.cbBuffer;
memset(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], cbPad, cbPad);
rtMd2BlockInitBuffered(pCtx);
rtMd2BlockProcess(pCtx);
pCtx->AltPrivate.cbBuffer = 0;
/*
* Add the checksum.
*/
rtMd2BlockInitNoChecksum(pCtx, pCtx->AltPrivate.abChecksum);
rtMd2BlockProcess(pCtx);
/*
* Done. Just copy out the digest.
*/
memcpy(pabDigest, pCtx->AltPrivate.abStateX, RTMD2_HASH_SIZE);
RT_ZERO(pCtx->AltPrivate);
pCtx->AltPrivate.cbBuffer = UINT8_MAX;
}
RT_EXPORT_SYMBOL(RTMd2Final);
RTDECL(void) RTMd2(const void *pvBuf, size_t cbBuf, uint8_t pabDigest[RTMD2_HASH_SIZE])
{
RTMD2CONTEXT Ctx;
RTMd2Init(&Ctx);
RTMd2Update(&Ctx, pvBuf, cbBuf);
RTMd2Final(&Ctx, pabDigest);
}
RT_EXPORT_SYMBOL(RTMd2);
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