Mercurial > hg > octave-kai > gnulib-hg
annotate lib/md2.c @ 9659:5680cf5b5595
md2: clarify comments to say that alignment is not required.
* lib/md2.h: Remove warning about alignment in comment.
* lib/md2.c (md2_read_ctx, md2_finish_ctx): Doc fix, alignment
has never been required.
| author | Simon Josefsson <simon@josefsson.org> |
|---|---|
| date | Thu, 31 Jan 2008 11:10:36 +0100 |
| parents | a88f85e4728f |
| children | e8fbc5424b99 |
| rev | line source |
|---|---|
| 6431 | 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. | |
|
9659
5680cf5b5595
md2: clarify comments to say that alignment is not required.
Simon Josefsson <simon@josefsson.org>
parents:
7584
diff
changeset
|
3 Copyright (C) 1995,1996,1997,1999,2000,2001,2002,2003,2005,2006,2008 |
| 6431 | 4 Free Software Foundation, Inc. |
| 5 | |
| 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 | |
| 9 later version. | |
| 10 | |
| 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. | |
| 15 | |
| 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. */ | |
| 19 | |
| 20 /* Adapted by Simon Josefsson from public domain Libtomcrypt 1.06 by | |
| 21 Tom St Denis. */ | |
| 22 | |
|
7584
a88f85e4728f
* lib/arcfour.c: Assume config.h.
Eric Blake <ebb9@byu.net>
parents:
6431
diff
changeset
|
23 #include <config.h> |
| 6431 | 24 |
| 25 #include "md2.h" | |
| 26 | |
| 27 #include <string.h> | |
| 28 #include <sys/types.h> | |
| 29 | |
| 30 #include <minmax.h> | |
| 31 | |
| 32 #if USE_UNLOCKED_IO | |
| 33 # include "unlocked-io.h" | |
| 34 #endif | |
| 35 | |
| 36 #define BLOCKSIZE 4096 | |
| 37 #if BLOCKSIZE % 64 != 0 | |
| 38 # error "invalid BLOCKSIZE" | |
| 39 #endif | |
| 40 | |
| 41 static void md2_update_chksum (struct md2_ctx *md); | |
| 42 static void md2_compress (struct md2_ctx *md); | |
| 43 | |
| 44 /* Initialize structure containing state of computation. | |
| 45 (RFC 1319, 3.3: Step 3) */ | |
| 46 void | |
| 47 md2_init_ctx (struct md2_ctx *ctx) | |
| 48 { | |
| 49 memset (ctx->X, 0, sizeof (ctx->X)); | |
| 50 memset (ctx->chksum, 0, sizeof (ctx->chksum)); | |
| 51 memset (ctx->buf, 0, sizeof (ctx->buf)); | |
| 52 ctx->curlen = 0; | |
| 53 } | |
| 54 | |
| 55 /* Put result from CTX in first 16 bytes following RESBUF. The result | |
|
9659
5680cf5b5595
md2: clarify comments to say that alignment is not required.
Simon Josefsson <simon@josefsson.org>
parents:
7584
diff
changeset
|
56 must be in little endian byte order. */ |
| 6431 | 57 void * |
| 58 md2_read_ctx (const struct md2_ctx *ctx, void *resbuf) | |
| 59 { | |
| 60 memcpy (resbuf, ctx->X, 16); | |
| 61 | |
| 62 return resbuf; | |
| 63 } | |
| 64 | |
| 65 /* Process the remaining bytes in the internal buffer and the usual | |
|
9659
5680cf5b5595
md2: clarify comments to say that alignment is not required.
Simon Josefsson <simon@josefsson.org>
parents:
7584
diff
changeset
|
66 prolog according to the standard and write the result to RESBUF. */ |
| 6431 | 67 void * |
| 68 md2_finish_ctx (struct md2_ctx *ctx, void *resbuf) | |
| 69 { | |
| 70 unsigned long i, k; | |
| 71 | |
| 72 /* pad the message */ | |
| 73 k = 16 - ctx->curlen; | |
| 74 for (i = ctx->curlen; i < 16; i++) | |
| 75 { | |
| 76 ctx->buf[i] = (unsigned char) k; | |
| 77 } | |
| 78 | |
| 79 /* hash and update */ | |
| 80 md2_compress (ctx); | |
| 81 md2_update_chksum (ctx); | |
| 82 | |
| 83 /* hash checksum */ | |
| 84 memcpy (ctx->buf, ctx->chksum, 16); | |
| 85 md2_compress (ctx); | |
| 86 | |
| 87 return md2_read_ctx (ctx, resbuf); | |
| 88 } | |
| 89 | |
| 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. */ | |
| 93 int | |
| 94 md2_stream (FILE *stream, void *resblock) | |
| 95 { | |
| 96 struct md2_ctx ctx; | |
| 97 char buffer[BLOCKSIZE + 72]; | |
| 98 size_t sum; | |
| 99 | |
| 100 /* Initialize the computation context. */ | |
| 101 md2_init_ctx (&ctx); | |
| 102 | |
| 103 /* Iterate over full file contents. */ | |
| 104 while (1) | |
| 105 { | |
| 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. */ | |
| 109 size_t n; | |
| 110 sum = 0; | |
| 111 | |
| 112 /* Read block. Take care for partial reads. */ | |
| 113 while (1) | |
| 114 { | |
| 115 n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream); | |
| 116 | |
| 117 sum += n; | |
| 118 | |
| 119 if (sum == BLOCKSIZE) | |
| 120 break; | |
| 121 | |
| 122 if (n == 0) | |
| 123 { | |
| 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 | |
| 126 or EWOULDBLOCK. */ | |
| 127 if (ferror (stream)) | |
| 128 return 1; | |
| 129 goto process_partial_block; | |
| 130 } | |
| 131 | |
| 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. */ | |
| 135 if (feof (stream)) | |
| 136 goto process_partial_block; | |
| 137 } | |
| 138 | |
| 139 /* Process buffer with BLOCKSIZE bytes. Note that | |
| 140 BLOCKSIZE % 64 == 0 | |
| 141 */ | |
| 142 md2_process_block (buffer, BLOCKSIZE, &ctx); | |
| 143 } | |
| 144 | |
| 145 process_partial_block:; | |
| 146 | |
| 147 /* Process any remaining bytes. */ | |
| 148 if (sum > 0) | |
| 149 md2_process_bytes (buffer, sum, &ctx); | |
| 150 | |
| 151 /* Construct result in desired memory. */ | |
| 152 md2_finish_ctx (&ctx, resblock); | |
| 153 return 0; | |
| 154 } | |
| 155 | |
| 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 | |
| 159 digest. */ | |
| 160 void * | |
| 161 md2_buffer (const char *buffer, size_t len, void *resblock) | |
| 162 { | |
| 163 struct md2_ctx ctx; | |
| 164 | |
| 165 /* Initialize the computation context. */ | |
| 166 md2_init_ctx (&ctx); | |
| 167 | |
| 168 /* Process whole buffer but last len % 64 bytes. */ | |
| 169 md2_process_block (buffer, len, &ctx); | |
| 170 | |
| 171 /* Put result in desired memory area. */ | |
| 172 return md2_finish_ctx (&ctx, resblock); | |
| 173 } | |
| 174 | |
| 175 void | |
| 176 md2_process_bytes (const void *buffer, size_t len, struct md2_ctx *ctx) | |
| 177 { | |
| 178 const char *in = buffer; | |
| 179 unsigned long n; | |
| 180 | |
| 181 while (len > 0) | |
| 182 { | |
| 183 n = MIN (len, (16 - ctx->curlen)); | |
| 184 memcpy (ctx->buf + ctx->curlen, in, (size_t) n); | |
| 185 ctx->curlen += n; | |
| 186 in += n; | |
| 187 len -= n; | |
| 188 | |
| 189 /* is 16 bytes full? */ | |
| 190 if (ctx->curlen == 16) | |
| 191 { | |
| 192 md2_compress (ctx); | |
| 193 md2_update_chksum (ctx); | |
| 194 ctx->curlen = 0; | |
| 195 } | |
| 196 } | |
| 197 } | |
| 198 | |
| 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 | |
| 218 }; | |
| 219 | |
| 220 /* adds 16 bytes to the checksum */ | |
| 221 static void | |
| 222 md2_update_chksum (struct md2_ctx *ctx) | |
| 223 { | |
| 224 int j; | |
| 225 unsigned char L; | |
| 226 | |
| 227 L = ctx->chksum[15]; | |
| 228 for (j = 0; j < 16; j++) | |
| 229 { | |
| 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); | |
| 233 } | |
| 234 } | |
| 235 | |
| 236 static void | |
| 237 md2_compress (struct md2_ctx *ctx) | |
| 238 { | |
| 239 size_t j, k; | |
| 240 unsigned char t; | |
| 241 | |
| 242 /* copy block */ | |
| 243 for (j = 0; j < 16; j++) | |
| 244 { | |
| 245 ctx->X[16 + j] = ctx->buf[j]; | |
| 246 ctx->X[32 + j] = ctx->X[j] ^ ctx->X[16 + j]; | |
| 247 } | |
| 248 | |
| 249 t = (unsigned char) 0; | |
| 250 | |
| 251 /* do 18 rounds */ | |
| 252 for (j = 0; j < 18; j++) | |
| 253 { | |
| 254 for (k = 0; k < 48; k++) | |
| 255 { | |
| 256 t = (ctx->X[k] ^= PI_SUBST[(int) (t & 255)]); | |
| 257 } | |
| 258 t = (t + (unsigned char) j) & 255; | |
| 259 } | |
| 260 } | |
| 261 | |
| 262 /* Process LEN bytes of BUFFER, accumulating context into CTX. */ | |
| 263 void | |
| 264 md2_process_block (const void *buffer, size_t len, struct md2_ctx *ctx) | |
| 265 { | |
| 266 md2_process_bytes (buffer, len, ctx); | |
| 267 } |