1 /* Functions to compute MD2 message digest of files or memory blocks.
2 according to the definition of MD2 in RFC 1319 from April 1992.
3 Copyright (C) 1995,1996,1997,1999,2000,2001,2002,2003,2005,2006,2008
4 Free Software Foundation, Inc.
6 This program is free software; you can redistribute it and/or modify it
7 under the terms of the GNU General Public License as published by the
8 Free Software Foundation; either version 2, or (at your option) any
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software Foundation,
18 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
20 /* Adapted by Simon Josefsson from public domain Libtomcrypt 1.06 by
28 #include <sys/types.h>
33 # include "unlocked-io.h"
36 #define BLOCKSIZE 4096
37 #if BLOCKSIZE % 64 != 0
38 # error "invalid BLOCKSIZE"
41 static void md2_update_chksum (struct md2_ctx *md);
42 static void md2_compress (struct md2_ctx *md);
44 /* Initialize structure containing state of computation.
45 (RFC 1319, 3.3: Step 3) */
47 md2_init_ctx (struct md2_ctx *ctx)
49 memset (ctx->X, 0, sizeof (ctx->X));
50 memset (ctx->chksum, 0, sizeof (ctx->chksum));
51 memset (ctx->buf, 0, sizeof (ctx->buf));
55 /* Put result from CTX in first 16 bytes following RESBUF. The result
56 must be in little endian byte order. */
58 md2_read_ctx (const struct md2_ctx *ctx, void *resbuf)
60 memcpy (resbuf, ctx->X, 16);
65 /* Process the remaining bytes in the internal buffer and the usual
66 prolog according to the standard and write the result to RESBUF. */
68 md2_finish_ctx (struct md2_ctx *ctx, void *resbuf)
74 for (i = ctx->curlen; i < 16; i++)
76 ctx->buf[i] = (unsigned char) k;
81 md2_update_chksum (ctx);
84 memcpy (ctx->buf, ctx->chksum, 16);
87 return md2_read_ctx (ctx, resbuf);
90 /* Compute MD2 message digest for bytes read from STREAM. The
91 resulting message digest number will be written into the 16 bytes
92 beginning at RESBLOCK. */
94 md2_stream (FILE *stream, void *resblock)
97 char buffer[BLOCKSIZE + 72];
100 /* Initialize the computation context. */
103 /* Iterate over full file contents. */
106 /* We read the file in blocks of BLOCKSIZE bytes. One call of the
107 computation function processes the whole buffer so that with the
108 next round of the loop another block can be read. */
112 /* Read block. Take care for partial reads. */
115 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
119 if (sum == BLOCKSIZE)
124 /* Check for the error flag IFF N == 0, so that we don't
125 exit the loop after a partial read due to e.g., EAGAIN
129 goto process_partial_block;
132 /* We've read at least one byte, so ignore errors. But always
133 check for EOF, since feof may be true even though N > 0.
134 Otherwise, we could end up calling fread after EOF. */
136 goto process_partial_block;
139 /* Process buffer with BLOCKSIZE bytes. Note that
142 md2_process_block (buffer, BLOCKSIZE, &ctx);
145 process_partial_block:;
147 /* Process any remaining bytes. */
149 md2_process_bytes (buffer, sum, &ctx);
151 /* Construct result in desired memory. */
152 md2_finish_ctx (&ctx, resblock);
156 /* Compute MD5 message digest for LEN bytes beginning at BUFFER. The
157 result is always in little endian byte order, so that a byte-wise
158 output yields to the wanted ASCII representation of the message
161 md2_buffer (const char *buffer, size_t len, void *resblock)
165 /* Initialize the computation context. */
168 /* Process whole buffer but last len % 64 bytes. */
169 md2_process_block (buffer, len, &ctx);
171 /* Put result in desired memory area. */
172 return md2_finish_ctx (&ctx, resblock);
176 md2_process_bytes (const void *buffer, size_t len, struct md2_ctx *ctx)
178 const char *in = buffer;
183 n = MIN (len, (16 - ctx->curlen));
184 memcpy (ctx->buf + ctx->curlen, in, (size_t) n);
189 /* is 16 bytes full? */
190 if (ctx->curlen == 16)
193 md2_update_chksum (ctx);
199 static const unsigned char PI_SUBST[256] = {
200 41, 46, 67, 201, 162, 216, 124, 1, 61, 54, 84, 161, 236, 240, 6,
201 19, 98, 167, 5, 243, 192, 199, 115, 140, 152, 147, 43, 217, 188,
202 76, 130, 202, 30, 155, 87, 60, 253, 212, 224, 22, 103, 66, 111, 24,
203 138, 23, 229, 18, 190, 78, 196, 214, 218, 158, 222, 73, 160, 251,
204 245, 142, 187, 47, 238, 122, 169, 104, 121, 145, 21, 178, 7, 63,
205 148, 194, 16, 137, 11, 34, 95, 33, 128, 127, 93, 154, 90, 144, 50,
206 39, 53, 62, 204, 231, 191, 247, 151, 3, 255, 25, 48, 179, 72, 165,
207 181, 209, 215, 94, 146, 42, 172, 86, 170, 198, 79, 184, 56, 210,
208 150, 164, 125, 182, 118, 252, 107, 226, 156, 116, 4, 241, 69, 157,
209 112, 89, 100, 113, 135, 32, 134, 91, 207, 101, 230, 45, 168, 2, 27,
210 96, 37, 173, 174, 176, 185, 246, 28, 70, 97, 105, 52, 64, 126, 15,
211 85, 71, 163, 35, 221, 81, 175, 58, 195, 92, 249, 206, 186, 197,
212 234, 38, 44, 83, 13, 110, 133, 40, 132, 9, 211, 223, 205, 244, 65,
213 129, 77, 82, 106, 220, 55, 200, 108, 193, 171, 250, 36, 225, 123,
214 8, 12, 189, 177, 74, 120, 136, 149, 139, 227, 99, 232, 109, 233,
215 203, 213, 254, 59, 0, 29, 57, 242, 239, 183, 14, 102, 88, 208, 228,
216 166, 119, 114, 248, 235, 117, 75, 10, 49, 68, 80, 180, 143, 237,
217 31, 26, 219, 153, 141, 51, 159, 17, 131, 20
220 /* adds 16 bytes to the checksum */
222 md2_update_chksum (struct md2_ctx *ctx)
228 for (j = 0; j < 16; j++)
230 /* caution, the RFC says its "C[j] = S[M[i*16+j] xor L]" but the
231 reference source code [and test vectors] say otherwise. */
232 L = (ctx->chksum[j] ^= PI_SUBST[(int) (ctx->buf[j] ^ L)] & 255);
237 md2_compress (struct md2_ctx *ctx)
243 for (j = 0; j < 16; j++)
245 ctx->X[16 + j] = ctx->buf[j];
246 ctx->X[32 + j] = ctx->X[j] ^ ctx->X[16 + j];
249 t = (unsigned char) 0;
252 for (j = 0; j < 18; j++)
254 for (k = 0; k < 48; k++)
256 t = (ctx->X[k] ^= PI_SUBST[(int) (t & 255)]);
258 t = (t + (unsigned char) j) & 255;
262 /* Process LEN bytes of BUFFER, accumulating context into CTX. */
264 md2_process_block (const void *buffer, size_t len, struct md2_ctx *ctx)
266 md2_process_bytes (buffer, len, ctx);