Ulrich Drepper | c54785a | 2008-02-01 18:05:21 +0000 | [diff] [blame] | 1 | /* Functions to compute SHA1 message digest of files or memory blocks. |
| 2 | according to the definition of SHA1 in FIPS 180-1 from April 1997. |
| 3 | Copyright (C) 2008 Red Hat, Inc. |
| 4 | This file is part of Red Hat elfutils. |
| 5 | Written by Ulrich Drepper <drepper@redhat.com>, 2008. |
| 6 | |
| 7 | Red Hat elfutils is free software; you can redistribute it and/or modify |
| 8 | it under the terms of the GNU General Public License as published by the |
| 9 | Free Software Foundation; version 2 of the License. |
| 10 | |
| 11 | Red Hat elfutils is distributed in the hope that it will be useful, but |
| 12 | WITHOUT ANY WARRANTY; without even the implied warranty of |
| 13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 14 | General Public License for more details. |
| 15 | |
| 16 | You should have received a copy of the GNU General Public License along |
| 17 | with Red Hat elfutils; if not, write to the Free Software Foundation, |
| 18 | Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301 USA. |
| 19 | |
| 20 | Red Hat elfutils is an included package of the Open Invention Network. |
| 21 | An included package of the Open Invention Network is a package for which |
| 22 | Open Invention Network licensees cross-license their patents. No patent |
| 23 | license is granted, either expressly or impliedly, by designation as an |
| 24 | included package. Should you wish to participate in the Open Invention |
| 25 | Network licensing program, please visit www.openinventionnetwork.com |
| 26 | <http://www.openinventionnetwork.com>. */ |
| 27 | |
| 28 | #ifdef HAVE_CONFIG_H |
| 29 | # include <config.h> |
| 30 | #endif |
| 31 | |
| 32 | #include <endian.h> |
| 33 | #include <stdlib.h> |
| 34 | #include <string.h> |
| 35 | #include <sys/types.h> |
| 36 | |
| 37 | #include "sha1.h" |
| 38 | |
| 39 | #if __BYTE_ORDER == __LITTLE_ENDIAN |
| 40 | # include <byteswap.h> |
| 41 | # define SWAP(n) bswap_32 (n) |
| 42 | #else |
| 43 | # define SWAP(n) (n) |
| 44 | #endif |
| 45 | |
| 46 | |
| 47 | /* This array contains the bytes used to pad the buffer to the next |
| 48 | 64-byte boundary. */ |
| 49 | static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; |
| 50 | |
| 51 | |
| 52 | /* Initialize structure containing state of computation. */ |
| 53 | void |
| 54 | sha1_init_ctx (ctx) |
| 55 | struct sha1_ctx *ctx; |
| 56 | { |
| 57 | ctx->A = 0x67452301; |
| 58 | ctx->B = 0xefcdab89; |
| 59 | ctx->C = 0x98badcfe; |
| 60 | ctx->D = 0x10325476; |
| 61 | ctx->E = 0xc3d2e1f0; |
| 62 | |
| 63 | ctx->total[0] = ctx->total[1] = 0; |
| 64 | ctx->buflen = 0; |
| 65 | } |
| 66 | |
| 67 | /* Put result from CTX in first 20 bytes following RESBUF. The result |
| 68 | must be in little endian byte order. |
| 69 | |
| 70 | IMPORTANT: On some systems it is required that RESBUF is correctly |
| 71 | aligned for a 32 bits value. */ |
| 72 | void * |
| 73 | sha1_read_ctx (ctx, resbuf) |
| 74 | const struct sha1_ctx *ctx; |
| 75 | void *resbuf; |
| 76 | { |
| 77 | ((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A); |
| 78 | ((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B); |
| 79 | ((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C); |
| 80 | ((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D); |
| 81 | ((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E); |
| 82 | |
| 83 | return resbuf; |
| 84 | } |
| 85 | |
| 86 | /* Process the remaining bytes in the internal buffer and the usual |
| 87 | prolog according to the standard and write the result to RESBUF. |
| 88 | |
| 89 | IMPORTANT: On some systems it is required that RESBUF is correctly |
| 90 | aligned for a 32 bits value. */ |
| 91 | void * |
| 92 | sha1_finish_ctx (ctx, resbuf) |
| 93 | struct sha1_ctx *ctx; |
| 94 | void *resbuf; |
| 95 | { |
| 96 | /* Take yet unprocessed bytes into account. */ |
| 97 | sha1_uint32 bytes = ctx->buflen; |
| 98 | size_t pad; |
| 99 | |
| 100 | /* Now count remaining bytes. */ |
| 101 | ctx->total[0] += bytes; |
| 102 | if (ctx->total[0] < bytes) |
| 103 | ++ctx->total[1]; |
| 104 | |
| 105 | pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; |
| 106 | memcpy (&ctx->buffer[bytes], fillbuf, pad); |
| 107 | |
| 108 | /* Put the 64-bit file length in *bits* at the end of the buffer. */ |
| 109 | *(sha1_uint32 *) &ctx->buffer[bytes + pad] = SWAP ((ctx->total[1] << 3) | |
| 110 | (ctx->total[0] >> 29)); |
| 111 | *(sha1_uint32 *) &ctx->buffer[bytes + pad + 4] = SWAP (ctx->total[0] << 3); |
| 112 | |
| 113 | /* Process last bytes. */ |
| 114 | sha1_process_block (ctx->buffer, bytes + pad + 8, ctx); |
| 115 | |
| 116 | return sha1_read_ctx (ctx, resbuf); |
| 117 | } |
| 118 | |
| 119 | |
| 120 | void |
| 121 | sha1_process_bytes (buffer, len, ctx) |
| 122 | const void *buffer; |
| 123 | size_t len; |
| 124 | struct sha1_ctx *ctx; |
| 125 | { |
| 126 | /* When we already have some bits in our internal buffer concatenate |
| 127 | both inputs first. */ |
| 128 | if (ctx->buflen != 0) |
| 129 | { |
| 130 | size_t left_over = ctx->buflen; |
| 131 | size_t add = 128 - left_over > len ? len : 128 - left_over; |
| 132 | |
| 133 | memcpy (&ctx->buffer[left_over], buffer, add); |
| 134 | ctx->buflen += add; |
| 135 | |
| 136 | if (ctx->buflen > 64) |
| 137 | { |
| 138 | sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx); |
| 139 | |
| 140 | ctx->buflen &= 63; |
| 141 | /* The regions in the following copy operation cannot overlap. */ |
| 142 | memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], |
| 143 | ctx->buflen); |
| 144 | } |
| 145 | |
| 146 | buffer = (const char *) buffer + add; |
| 147 | len -= add; |
| 148 | } |
| 149 | |
| 150 | /* Process available complete blocks. */ |
| 151 | if (len >= 64) |
| 152 | { |
| 153 | #if !_STRING_ARCH_unaligned |
| 154 | /* To check alignment gcc has an appropriate operator. Other |
| 155 | compilers don't. */ |
| 156 | # if __GNUC__ >= 2 |
| 157 | # define UNALIGNED_P(p) (((sha1_uintptr) p) % __alignof__ (sha1_uint32) != 0) |
| 158 | # else |
| 159 | # define UNALIGNED_P(p) (((sha1_uintptr) p) % sizeof (sha1_uint32) != 0) |
| 160 | # endif |
| 161 | if (UNALIGNED_P (buffer)) |
| 162 | while (len > 64) |
| 163 | { |
| 164 | sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); |
| 165 | buffer = (const char *) buffer + 64; |
| 166 | len -= 64; |
| 167 | } |
| 168 | else |
| 169 | #endif |
| 170 | { |
| 171 | sha1_process_block (buffer, len & ~63, ctx); |
| 172 | buffer = (const char *) buffer + (len & ~63); |
| 173 | len &= 63; |
| 174 | } |
| 175 | } |
| 176 | |
| 177 | /* Move remaining bytes in internal buffer. */ |
| 178 | if (len > 0) |
| 179 | { |
| 180 | size_t left_over = ctx->buflen; |
| 181 | |
| 182 | memcpy (&ctx->buffer[left_over], buffer, len); |
| 183 | left_over += len; |
| 184 | if (left_over >= 64) |
| 185 | { |
| 186 | sha1_process_block (ctx->buffer, 64, ctx); |
| 187 | left_over -= 64; |
| 188 | memcpy (ctx->buffer, &ctx->buffer[64], left_over); |
| 189 | } |
| 190 | ctx->buflen = left_over; |
| 191 | } |
| 192 | } |
| 193 | |
| 194 | |
| 195 | /* These are the four functions used in the four steps of the SHA1 algorithm |
| 196 | and defined in the FIPS 180-1. */ |
| 197 | /* #define FF(b, c, d) ((b & c) | (~b & d)) */ |
| 198 | #define FF(b, c, d) (d ^ (b & (c ^ d))) |
| 199 | #define FG(b, c, d) (b ^ c ^ d) |
| 200 | /* define FH(b, c, d) ((b & c) | (b & d) | (c & d)) */ |
| 201 | #define FH(b, c, d) (((b | c) & d) | (b & c)) |
| 202 | |
| 203 | /* It is unfortunate that C does not provide an operator for cyclic |
| 204 | rotation. Hope the C compiler is smart enough. */ |
| 205 | #define CYCLIC(w, s) (((w) << s) | ((w) >> (32 - s))) |
| 206 | |
| 207 | /* Magic constants. */ |
| 208 | #define K0 0x5a827999 |
| 209 | #define K1 0x6ed9eba1 |
| 210 | #define K2 0x8f1bbcdc |
| 211 | #define K3 0xca62c1d6 |
| 212 | |
| 213 | |
| 214 | /* Process LEN bytes of BUFFER, accumulating context into CTX. |
| 215 | It is assumed that LEN % 64 == 0. */ |
| 216 | |
| 217 | void |
| 218 | sha1_process_block (buffer, len, ctx) |
| 219 | const void *buffer; |
| 220 | size_t len; |
| 221 | struct sha1_ctx *ctx; |
| 222 | { |
| 223 | sha1_uint32 computed_words[16]; |
| 224 | #define W(i) computed_words[(i) % 16] |
| 225 | const sha1_uint32 *words = buffer; |
| 226 | size_t nwords = len / sizeof (sha1_uint32); |
| 227 | const sha1_uint32 *endp = words + nwords; |
| 228 | sha1_uint32 A = ctx->A; |
| 229 | sha1_uint32 B = ctx->B; |
| 230 | sha1_uint32 C = ctx->C; |
| 231 | sha1_uint32 D = ctx->D; |
| 232 | sha1_uint32 E = ctx->E; |
| 233 | |
| 234 | /* First increment the byte count. FIPS 180-1 specifies the possible |
| 235 | length of the file up to 2^64 bits. Here we only compute the |
| 236 | number of bytes. Do a double word increment. */ |
| 237 | ctx->total[0] += len; |
| 238 | if (ctx->total[0] < len) |
| 239 | ++ctx->total[1]; |
| 240 | |
| 241 | /* Process all bytes in the buffer with 64 bytes in each round of |
| 242 | the loop. */ |
| 243 | while (words < endp) |
| 244 | { |
| 245 | sha1_uint32 A_save = A; |
| 246 | sha1_uint32 B_save = B; |
| 247 | sha1_uint32 C_save = C; |
| 248 | sha1_uint32 D_save = D; |
| 249 | sha1_uint32 E_save = E; |
| 250 | |
| 251 | /* First round: using the given function, the context and a constant |
| 252 | the next context is computed. Because the algorithms processing |
| 253 | unit is a 32-bit word and it is determined to work on words in |
| 254 | little endian byte order we perhaps have to change the byte order |
| 255 | before the computation. */ |
| 256 | |
| 257 | #define OP(i, a, b, c, d, e) \ |
| 258 | do \ |
| 259 | { \ |
| 260 | W (i) = SWAP (*words); \ |
| 261 | e = CYCLIC (a, 5) + FF (b, c, d) + e + W (i) + K0; \ |
| 262 | ++words; \ |
| 263 | b = CYCLIC (b, 30); \ |
| 264 | } \ |
| 265 | while (0) |
| 266 | |
| 267 | /* Steps 0 to 15. */ |
| 268 | OP (0, A, B, C, D, E); |
| 269 | OP (1, E, A, B, C, D); |
| 270 | OP (2, D, E, A, B, C); |
| 271 | OP (3, C, D, E, A, B); |
| 272 | OP (4, B, C, D, E, A); |
| 273 | OP (5, A, B, C, D, E); |
| 274 | OP (6, E, A, B, C, D); |
| 275 | OP (7, D, E, A, B, C); |
| 276 | OP (8, C, D, E, A, B); |
| 277 | OP (9, B, C, D, E, A); |
| 278 | OP (10, A, B, C, D, E); |
| 279 | OP (11, E, A, B, C, D); |
| 280 | OP (12, D, E, A, B, C); |
| 281 | OP (13, C, D, E, A, B); |
| 282 | OP (14, B, C, D, E, A); |
| 283 | OP (15, A, B, C, D, E); |
| 284 | |
| 285 | /* For the remaining 64 steps we have a more complicated |
| 286 | computation of the input data-derived values. Redefine the |
| 287 | macro to take an additional second argument specifying the |
| 288 | function to use and a new last parameter for the magic |
| 289 | constant. */ |
| 290 | #undef OP |
| 291 | #define OP(i, f, a, b, c, d, e, K) \ |
| 292 | do \ |
| 293 | { \ |
| 294 | W (i) = CYCLIC (W (i - 3) ^ W (i - 8) ^ W (i - 14) ^ W (i - 16), 1);\ |
| 295 | e = CYCLIC (a, 5) + f (b, c, d) + e + W (i) + K; \ |
| 296 | b = CYCLIC (b, 30); \ |
| 297 | } \ |
| 298 | while (0) |
| 299 | |
| 300 | /* Steps 16 to 19. */ |
| 301 | OP (16, FF, E, A, B, C, D, K0); |
| 302 | OP (17, FF, D, E, A, B, C, K0); |
| 303 | OP (18, FF, C, D, E, A, B, K0); |
| 304 | OP (19, FF, B, C, D, E, A, K0); |
| 305 | |
| 306 | /* Steps 20 to 39. */ |
| 307 | OP (20, FG, A, B, C, D, E, K1); |
| 308 | OP (21, FG, E, A, B, C, D, K1); |
| 309 | OP (22, FG, D, E, A, B, C, K1); |
| 310 | OP (23, FG, C, D, E, A, B, K1); |
| 311 | OP (24, FG, B, C, D, E, A, K1); |
| 312 | OP (25, FG, A, B, C, D, E, K1); |
| 313 | OP (26, FG, E, A, B, C, D, K1); |
| 314 | OP (27, FG, D, E, A, B, C, K1); |
| 315 | OP (28, FG, C, D, E, A, B, K1); |
| 316 | OP (29, FG, B, C, D, E, A, K1); |
| 317 | OP (30, FG, A, B, C, D, E, K1); |
| 318 | OP (31, FG, E, A, B, C, D, K1); |
| 319 | OP (32, FG, D, E, A, B, C, K1); |
| 320 | OP (33, FG, C, D, E, A, B, K1); |
| 321 | OP (34, FG, B, C, D, E, A, K1); |
| 322 | OP (35, FG, A, B, C, D, E, K1); |
| 323 | OP (36, FG, E, A, B, C, D, K1); |
| 324 | OP (37, FG, D, E, A, B, C, K1); |
| 325 | OP (38, FG, C, D, E, A, B, K1); |
| 326 | OP (39, FG, B, C, D, E, A, K1); |
| 327 | |
| 328 | /* Steps 40 to 59. */ |
| 329 | OP (40, FH, A, B, C, D, E, K2); |
| 330 | OP (41, FH, E, A, B, C, D, K2); |
| 331 | OP (42, FH, D, E, A, B, C, K2); |
| 332 | OP (43, FH, C, D, E, A, B, K2); |
| 333 | OP (44, FH, B, C, D, E, A, K2); |
| 334 | OP (45, FH, A, B, C, D, E, K2); |
| 335 | OP (46, FH, E, A, B, C, D, K2); |
| 336 | OP (47, FH, D, E, A, B, C, K2); |
| 337 | OP (48, FH, C, D, E, A, B, K2); |
| 338 | OP (49, FH, B, C, D, E, A, K2); |
| 339 | OP (50, FH, A, B, C, D, E, K2); |
| 340 | OP (51, FH, E, A, B, C, D, K2); |
| 341 | OP (52, FH, D, E, A, B, C, K2); |
| 342 | OP (53, FH, C, D, E, A, B, K2); |
| 343 | OP (54, FH, B, C, D, E, A, K2); |
| 344 | OP (55, FH, A, B, C, D, E, K2); |
| 345 | OP (56, FH, E, A, B, C, D, K2); |
| 346 | OP (57, FH, D, E, A, B, C, K2); |
| 347 | OP (58, FH, C, D, E, A, B, K2); |
| 348 | OP (59, FH, B, C, D, E, A, K2); |
| 349 | |
| 350 | /* Steps 60 to 79. */ |
| 351 | OP (60, FG, A, B, C, D, E, K3); |
| 352 | OP (61, FG, E, A, B, C, D, K3); |
| 353 | OP (62, FG, D, E, A, B, C, K3); |
| 354 | OP (63, FG, C, D, E, A, B, K3); |
| 355 | OP (64, FG, B, C, D, E, A, K3); |
| 356 | OP (65, FG, A, B, C, D, E, K3); |
| 357 | OP (66, FG, E, A, B, C, D, K3); |
| 358 | OP (67, FG, D, E, A, B, C, K3); |
| 359 | OP (68, FG, C, D, E, A, B, K3); |
| 360 | OP (69, FG, B, C, D, E, A, K3); |
| 361 | OP (70, FG, A, B, C, D, E, K3); |
| 362 | OP (71, FG, E, A, B, C, D, K3); |
| 363 | OP (72, FG, D, E, A, B, C, K3); |
| 364 | OP (73, FG, C, D, E, A, B, K3); |
| 365 | OP (74, FG, B, C, D, E, A, K3); |
| 366 | OP (75, FG, A, B, C, D, E, K3); |
| 367 | OP (76, FG, E, A, B, C, D, K3); |
| 368 | OP (77, FG, D, E, A, B, C, K3); |
| 369 | OP (78, FG, C, D, E, A, B, K3); |
| 370 | OP (79, FG, B, C, D, E, A, K3); |
| 371 | |
| 372 | /* Add the starting values of the context. */ |
| 373 | A += A_save; |
| 374 | B += B_save; |
| 375 | C += C_save; |
| 376 | D += D_save; |
| 377 | E += E_save; |
| 378 | } |
| 379 | |
| 380 | /* Put checksum in context given as argument. */ |
| 381 | ctx->A = A; |
| 382 | ctx->B = B; |
| 383 | ctx->C = C; |
| 384 | ctx->D = D; |
| 385 | ctx->E = E; |
| 386 | } |