VirtualBox

source: vbox/trunk/src/VBox/Runtime/common/checksum/alt-md2.cpp

Last change on this file was 98103, checked in by vboxsync, 16 months ago

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1/* $Id: alt-md2.cpp 98103 2023-01-17 14:15:46Z vboxsync $ */
2/** @file
3 * IPRT - Message-Digest Algorithm 2, Alternative Implementation.
4 */
5
6/*
7 * Copyright (C) 2009-2023 Oracle and/or its affiliates.
8 *
9 * This file is part of VirtualBox base platform packages, as
10 * available from https://www.virtualbox.org.
11 *
12 * This program is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU General Public License
14 * as published by the Free Software Foundation, in version 3 of the
15 * License.
16 *
17 * This program is distributed in the hope that it will be useful, but
18 * WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * General Public License for more details.
21 *
22 * You should have received a copy of the GNU General Public License
23 * along with this program; if not, see <https://www.gnu.org/licenses>.
24 *
25 * The contents of this file may alternatively be used under the terms
26 * of the Common Development and Distribution License Version 1.0
27 * (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
28 * in the VirtualBox distribution, in which case the provisions of the
29 * CDDL are applicable instead of those of the GPL.
30 *
31 * You may elect to license modified versions of this file under the
32 * terms and conditions of either the GPL or the CDDL or both.
33 *
34 * SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
35 */
36
37
38/*********************************************************************************************************************************
39* Defined Constants And Macros *
40*********************************************************************************************************************************/
41/** The MD2 block size. */
42#define RTMD2_BLOCK_SIZE 16
43/** The offset of the buffer into RTMD2ALTPRIVATECTX::abStateX. */
44#define RTMD2_BUF_OFF RTMD2_BLOCK_SIZE
45
46
47/*********************************************************************************************************************************
48* Header Files *
49*********************************************************************************************************************************/
50#include "internal/iprt.h"
51#include <iprt/types.h>
52
53
54/** Our private context structure. */
55typedef struct RTMD2ALTPRIVATECTX
56{
57 /** The state (X).
58 * The staging buffer starts byte 16. */
59 uint8_t abStateX[RTMD2_BLOCK_SIZE * 3];
60 /** The checksum. */
61 uint8_t abChecksum[RTMD2_BLOCK_SIZE];
62 /** The number of buffered bytes. */
63 uint8_t cbBuffer;
64} RTMD2ALTPRIVATECTX;
65
66#define RT_MD2_PRIVATE_ALT_CONTEXT
67#include <iprt/md2.h>
68
69#include <iprt/assert.h>
70#include <iprt/string.h>
71
72AssertCompile(RT_SIZEOFMEMB(RTMD2CONTEXT, abPadding) >= RT_SIZEOFMEMB(RTMD2CONTEXT, AltPrivate));
73
74
75/*********************************************************************************************************************************
76* Global Variables *
77*********************************************************************************************************************************/
78/** PI substitation used by MD2. */
79static uint8_t const g_PiSubst[256] =
80{
81 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6, 19,
82 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188, 76, 130, 202,
83 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24, 138, 23, 229, 18,
84 190, 78, 196, 214, 218, 158, 222, 73, 160, 251, 245, 142, 187, 47, 238, 122,
85 169, 104, 121, 145, 21, 178, 7, 63, 148, 194, 16, 137, 11, 34, 95, 33,
86 128, 127, 93, 154, 90, 144, 50, 39, 53, 62, 204, 231, 191, 247, 151, 3,
87 255, 25, 48, 179, 72, 165, 181, 209, 215, 94, 146, 42, 172, 86, 170, 198,
88 79, 184, 56, 210, 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241,
89 69, 157, 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2,
90 27, 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
91 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197, 234, 38,
92 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65, 129, 77, 82,
93 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123, 8, 12, 189, 177, 74,
94 120, 136, 149, 139, 227, 99, 232, 109, 233, 203, 213, 254, 59, 0, 29, 57,
95 242, 239, 183, 14, 102, 88, 208, 228, 166, 119, 114, 248, 235, 117, 75, 10,
96 49, 68, 80, 180, 143, 237, 31, 26, 219, 153, 141, 51, 159, 17, 131, 20,
97};
98
99
100RTDECL(void) RTMd2Init(PRTMD2CONTEXT pCtx)
101{
102 pCtx->AltPrivate.cbBuffer = 0;
103 RT_ZERO(pCtx->AltPrivate.abStateX);
104 RT_ZERO(pCtx->AltPrivate.abChecksum);
105}
106RT_EXPORT_SYMBOL(RTMd2Init);
107
108
109
110/**
111 * Initializes the processing of a whole block directly from the input buffer.
112 *
113 * This will update the checksum as well as initializing abStateX.
114 *
115 * @param pCtx The MD2 context.
116 * @param pbBlock The block.
117 */
118DECLINLINE(void) rtMd2BlockInit(PRTMD2CONTEXT pCtx, const uint8_t *pbBlock)
119{
120 uint8_t bL = pCtx->AltPrivate.abChecksum[15];
121 for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
122 {
123 uint8_t bIn = pbBlock[j];
124 pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE] = bIn;
125 pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
126 bL = pCtx->AltPrivate.abChecksum[j] ^= g_PiSubst[bIn ^ bL];
127 }
128}
129
130
131/**
132 * Special version of rtMd2BlockInit that does not update the checksum.
133 *
134 * This is used in the final round when adding the checksum to the calculation.
135 *
136 * @param pCtx The MD2 context.
137 * @param pbBlock The block (i.e. the checksum).
138 */
139DECLINLINE(void) rtMd2BlockInitNoChecksum(PRTMD2CONTEXT pCtx, const uint8_t *pbBlock)
140{
141 for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
142 {
143 uint8_t bIn = pbBlock[j];
144 pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE] = bIn;
145 pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
146 }
147}
148
149
150/**
151 * Initalizes the abStateX from a full buffer and update the checksum.
152 *
153 * The buffer is part of the abStateX structure (bytes 16 thru 31), so this
154 * is a somewhat reduced version of rtMd2BlockInit.
155 *
156 * @param pCtx The MD2 context.
157 */
158DECLINLINE(void) rtMd2BlockInitBuffered(PRTMD2CONTEXT pCtx)
159{
160 uint8_t bL = pCtx->AltPrivate.abChecksum[15];
161 for (unsigned j = 0; j < RTMD2_BLOCK_SIZE; j++)
162 {
163 uint8_t bIn = pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE];
164 pCtx->AltPrivate.abStateX[j + RTMD2_BLOCK_SIZE * 2] = bIn ^ pCtx->AltPrivate.abStateX[j];
165 bL = pCtx->AltPrivate.abChecksum[j] ^= g_PiSubst[bIn ^ bL];
166 }
167}
168
169
170/**
171 * Process the current block.
172 *
173 * Requires one of the rtMd2BlockInit functions to be called first.
174 *
175 * @param pCtx The MD2 context.
176 */
177DECLINLINE(void) rtMd2BlockProcess(PRTMD2CONTEXT pCtx)
178{
179 uint8_t bT = 0;
180 for (unsigned j = 0; j < 18; j++) /* 18 rounds */
181 {
182 for (unsigned k = 0; k < RTMD2_BLOCK_SIZE * 3; k++)
183 pCtx->AltPrivate.abStateX[k] = bT = pCtx->AltPrivate.abStateX[k] ^ g_PiSubst[bT];
184 bT += (uint8_t)j;
185 }
186}
187
188
189RTDECL(void) RTMd2Update(PRTMD2CONTEXT pCtx, const void *pvBuf, size_t cbBuf)
190{
191 Assert(pCtx->AltPrivate.cbBuffer < RTMD2_BLOCK_SIZE);
192 uint8_t const *pbBuf = (uint8_t const *)pvBuf;
193
194 /*
195 * Deal with buffered bytes first.
196 */
197 if (pCtx->AltPrivate.cbBuffer)
198 {
199 uint8_t cbMissing = RTMD2_BLOCK_SIZE - pCtx->AltPrivate.cbBuffer;
200 if (cbBuf >= cbMissing)
201 {
202 memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], pbBuf, cbMissing);
203 pbBuf += cbMissing;
204 cbBuf -= cbMissing;
205
206 rtMd2BlockInitBuffered(pCtx);
207 rtMd2BlockProcess(pCtx);
208
209 pCtx->AltPrivate.cbBuffer = 0;
210 }
211 else
212 {
213 memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], pbBuf, cbBuf);
214 pCtx->AltPrivate.cbBuffer += (uint8_t)cbBuf;
215 return;
216 }
217 }
218
219 /*
220 * Process full blocks directly from the input buffer.
221 */
222 while (cbBuf >= RTMD2_BLOCK_SIZE)
223 {
224 rtMd2BlockInit(pCtx, pbBuf);
225 rtMd2BlockProcess(pCtx);
226
227 pbBuf += RTMD2_BLOCK_SIZE;
228 cbBuf -= RTMD2_BLOCK_SIZE;
229 }
230
231 /*
232 * Stash any remaining bytes into the context buffer.
233 */
234 if (cbBuf > 0)
235 {
236 memcpy(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF], pbBuf, cbBuf);
237 pCtx->AltPrivate.cbBuffer = (uint8_t)cbBuf;
238 }
239}
240RT_EXPORT_SYMBOL(RTMd2Update);
241
242
243RTDECL(void) RTMd2Final(PRTMD2CONTEXT pCtx, uint8_t pabDigest[RTMD2_HASH_SIZE])
244{
245 Assert(pCtx->AltPrivate.cbBuffer < RTMD2_BLOCK_SIZE);
246
247 /*
248 * Pad the message to a multiple of 16 bytes. This is done even if the
249 * message already is a multiple of 16.
250 */
251 unsigned cbPad = RTMD2_BLOCK_SIZE - pCtx->AltPrivate.cbBuffer;
252 memset(&pCtx->AltPrivate.abStateX[RTMD2_BUF_OFF + pCtx->AltPrivate.cbBuffer], cbPad, cbPad);
253 rtMd2BlockInitBuffered(pCtx);
254 rtMd2BlockProcess(pCtx);
255 pCtx->AltPrivate.cbBuffer = 0;
256
257 /*
258 * Add the checksum.
259 */
260 rtMd2BlockInitNoChecksum(pCtx, pCtx->AltPrivate.abChecksum);
261 rtMd2BlockProcess(pCtx);
262
263 /*
264 * Done. Just copy out the digest.
265 */
266 memcpy(pabDigest, pCtx->AltPrivate.abStateX, RTMD2_HASH_SIZE);
267
268 RT_ZERO(pCtx->AltPrivate);
269 pCtx->AltPrivate.cbBuffer = UINT8_MAX;
270}
271RT_EXPORT_SYMBOL(RTMd2Final);
272
273
274RTDECL(void) RTMd2(const void *pvBuf, size_t cbBuf, uint8_t pabDigest[RTMD2_HASH_SIZE])
275{
276 RTMD2CONTEXT Ctx;
277 RTMd2Init(&Ctx);
278 RTMd2Update(&Ctx, pvBuf, cbBuf);
279 RTMd2Final(&Ctx, pabDigest);
280}
281RT_EXPORT_SYMBOL(RTMd2);
282
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