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) 2008-2011, 2015 Red Hat, Inc. 4 This file is part of elfutils. 5 Written by Ulrich Drepper <drepper (at) redhat.com>, 2008. 6 7 This file is free software; you can redistribute it and/or modify 8 it under the terms of either 9 10 * the GNU Lesser General Public License as published by the Free 11 Software Foundation; either version 3 of the License, or (at 12 your option) any later version 13 14 or 15 16 * the GNU General Public License as published by the Free 17 Software Foundation; either version 2 of the License, or (at 18 your option) any later version 19 20 or both in parallel, as here. 21 22 elfutils is distributed in the hope that it will be useful, but 23 WITHOUT ANY WARRANTY; without even the implied warranty of 24 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 25 General Public License for more details. 26 27 You should have received copies of the GNU General Public License and 28 the GNU Lesser General Public License along with this program. If 29 not, see <http://www.gnu.org/licenses/>. */ 30 31 #ifdef HAVE_CONFIG_H 32 # include <config.h> 33 #endif 34 35 #include <stdlib.h> 36 #include <string.h> 37 #include <sys/types.h> 38 39 #include "sha1.h" 40 #include "system.h" 41 42 #define SWAP(n) BE32 (n) 43 44 /* This array contains the bytes used to pad the buffer to the next 45 64-byte boundary. */ 46 static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; 47 48 49 /* Initialize structure containing state of computation. */ 50 void 51 sha1_init_ctx (struct sha1_ctx *ctx) 52 { 53 ctx->A = 0x67452301; 54 ctx->B = 0xefcdab89; 55 ctx->C = 0x98badcfe; 56 ctx->D = 0x10325476; 57 ctx->E = 0xc3d2e1f0; 58 59 ctx->total[0] = ctx->total[1] = 0; 60 ctx->buflen = 0; 61 } 62 63 /* Put result from CTX in first 20 bytes following RESBUF. The result 64 must be in little endian byte order. 65 66 IMPORTANT: On some systems it is required that RESBUF is correctly 67 aligned for a 32 bits value. */ 68 void * 69 sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf) 70 { 71 ((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A); 72 ((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B); 73 ((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C); 74 ((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D); 75 ((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E); 76 77 return resbuf; 78 } 79 80 static void 81 be64_copy (char *dest, uint64_t x) 82 { 83 for (size_t i = 8; i-- > 0; x >>= 8) 84 dest[i] = (uint8_t) x; 85 } 86 87 /* Process the remaining bytes in the internal buffer and the usual 88 prolog according to the standard and write the result to RESBUF. 89 90 IMPORTANT: On some systems it is required that RESBUF is correctly 91 aligned for a 32 bits value. */ 92 void * 93 sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf) 94 { 95 /* Take yet unprocessed bytes into account. */ 96 sha1_uint32 bytes = ctx->buflen; 97 size_t pad; 98 99 /* Now count remaining bytes. */ 100 ctx->total[0] += bytes; 101 if (ctx->total[0] < bytes) 102 ++ctx->total[1]; 103 104 pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes; 105 memcpy (&ctx->buffer[bytes], fillbuf, pad); 106 107 /* Put the 64-bit file length in *bits* at the end of the buffer. */ 108 const uint64_t bit_length = ((ctx->total[0] << 3) 109 + ((uint64_t) ((ctx->total[1] << 3) | 110 (ctx->total[0] >> 29)) << 32)); 111 be64_copy (&ctx->buffer[bytes + pad], bit_length); 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 (const void *buffer, size_t len, struct sha1_ctx *ctx) 122 { 123 /* When we already have some bits in our internal buffer concatenate 124 both inputs first. */ 125 if (ctx->buflen != 0) 126 { 127 size_t left_over = ctx->buflen; 128 size_t add = 128 - left_over > len ? len : 128 - left_over; 129 130 memcpy (&ctx->buffer[left_over], buffer, add); 131 ctx->buflen += add; 132 133 if (ctx->buflen > 64) 134 { 135 sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx); 136 137 ctx->buflen &= 63; 138 /* The regions in the following copy operation cannot overlap. */ 139 memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63], 140 ctx->buflen); 141 } 142 143 buffer = (const char *) buffer + add; 144 len -= add; 145 } 146 147 /* Process available complete blocks. */ 148 if (len >= 64) 149 { 150 #if !_STRING_ARCH_unaligned 151 /* To check alignment gcc has an appropriate operator. Other 152 compilers don't. */ 153 # if __GNUC__ >= 2 154 # define UNALIGNED_P(p) (((sha1_uintptr) p) % __alignof__ (sha1_uint32) != 0) 155 # else 156 # define UNALIGNED_P(p) (((sha1_uintptr) p) % sizeof (sha1_uint32) != 0) 157 # endif 158 if (UNALIGNED_P (buffer)) 159 while (len > 64) 160 { 161 sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); 162 buffer = (const char *) buffer + 64; 163 len -= 64; 164 } 165 else 166 #endif 167 { 168 sha1_process_block (buffer, len & ~63, ctx); 169 buffer = (const char *) buffer + (len & ~63); 170 len &= 63; 171 } 172 } 173 174 /* Move remaining bytes in internal buffer. */ 175 if (len > 0) 176 { 177 size_t left_over = ctx->buflen; 178 179 memcpy (&ctx->buffer[left_over], buffer, len); 180 left_over += len; 181 if (left_over >= 64) 182 { 183 sha1_process_block (ctx->buffer, 64, ctx); 184 left_over -= 64; 185 memcpy (ctx->buffer, &ctx->buffer[64], left_over); 186 } 187 ctx->buflen = left_over; 188 } 189 } 190 191 192 /* These are the four functions used in the four steps of the SHA1 algorithm 193 and defined in the FIPS 180-1. */ 194 /* #define FF(b, c, d) ((b & c) | (~b & d)) */ 195 #define FF(b, c, d) (d ^ (b & (c ^ d))) 196 #define FG(b, c, d) (b ^ c ^ d) 197 /* define FH(b, c, d) ((b & c) | (b & d) | (c & d)) */ 198 #define FH(b, c, d) (((b | c) & d) | (b & c)) 199 200 /* It is unfortunate that C does not provide an operator for cyclic 201 rotation. Hope the C compiler is smart enough. */ 202 #define CYCLIC(w, s) (((w) << s) | ((w) >> (32 - s))) 203 204 /* Magic constants. */ 205 #define K0 0x5a827999 206 #define K1 0x6ed9eba1 207 #define K2 0x8f1bbcdc 208 #define K3 0xca62c1d6 209 210 211 /* Process LEN bytes of BUFFER, accumulating context into CTX. 212 It is assumed that LEN % 64 == 0. */ 213 214 void 215 sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx) 216 { 217 sha1_uint32 computed_words[16]; 218 #define W(i) computed_words[(i) % 16] 219 const sha1_uint32 *words = buffer; 220 size_t nwords = len / sizeof (sha1_uint32); 221 const sha1_uint32 *endp = words + nwords; 222 sha1_uint32 A = ctx->A; 223 sha1_uint32 B = ctx->B; 224 sha1_uint32 C = ctx->C; 225 sha1_uint32 D = ctx->D; 226 sha1_uint32 E = ctx->E; 227 228 /* First increment the byte count. FIPS 180-1 specifies the possible 229 length of the file up to 2^64 bits. Here we only compute the 230 number of bytes. Do a double word increment. */ 231 ctx->total[0] += len; 232 if (ctx->total[0] < len) 233 ++ctx->total[1]; 234 235 /* Process all bytes in the buffer with 64 bytes in each round of 236 the loop. */ 237 while (words < endp) 238 { 239 sha1_uint32 A_save = A; 240 sha1_uint32 B_save = B; 241 sha1_uint32 C_save = C; 242 sha1_uint32 D_save = D; 243 sha1_uint32 E_save = E; 244 245 /* First round: using the given function, the context and a constant 246 the next context is computed. Because the algorithms processing 247 unit is a 32-bit word and it is determined to work on words in 248 little endian byte order we perhaps have to change the byte order 249 before the computation. */ 250 251 #define OP(i, a, b, c, d, e) \ 252 do \ 253 { \ 254 W (i) = SWAP (*words); \ 255 e = CYCLIC (a, 5) + FF (b, c, d) + e + W (i) + K0; \ 256 ++words; \ 257 b = CYCLIC (b, 30); \ 258 } \ 259 while (0) 260 261 /* Steps 0 to 15. */ 262 OP (0, A, B, C, D, E); 263 OP (1, E, A, B, C, D); 264 OP (2, D, E, A, B, C); 265 OP (3, C, D, E, A, B); 266 OP (4, B, C, D, E, A); 267 OP (5, A, B, C, D, E); 268 OP (6, E, A, B, C, D); 269 OP (7, D, E, A, B, C); 270 OP (8, C, D, E, A, B); 271 OP (9, B, C, D, E, A); 272 OP (10, A, B, C, D, E); 273 OP (11, E, A, B, C, D); 274 OP (12, D, E, A, B, C); 275 OP (13, C, D, E, A, B); 276 OP (14, B, C, D, E, A); 277 OP (15, A, B, C, D, E); 278 279 /* For the remaining 64 steps we have a more complicated 280 computation of the input data-derived values. Redefine the 281 macro to take an additional second argument specifying the 282 function to use and a new last parameter for the magic 283 constant. */ 284 #undef OP 285 #define OP(i, f, a, b, c, d, e, K) \ 286 do \ 287 { \ 288 W (i) = CYCLIC (W (i - 3) ^ W (i - 8) ^ W (i - 14) ^ W (i - 16), 1);\ 289 e = CYCLIC (a, 5) + f (b, c, d) + e + W (i) + K; \ 290 b = CYCLIC (b, 30); \ 291 } \ 292 while (0) 293 294 /* Steps 16 to 19. */ 295 OP (16, FF, E, A, B, C, D, K0); 296 OP (17, FF, D, E, A, B, C, K0); 297 OP (18, FF, C, D, E, A, B, K0); 298 OP (19, FF, B, C, D, E, A, K0); 299 300 /* Steps 20 to 39. */ 301 OP (20, FG, A, B, C, D, E, K1); 302 OP (21, FG, E, A, B, C, D, K1); 303 OP (22, FG, D, E, A, B, C, K1); 304 OP (23, FG, C, D, E, A, B, K1); 305 OP (24, FG, B, C, D, E, A, K1); 306 OP (25, FG, A, B, C, D, E, K1); 307 OP (26, FG, E, A, B, C, D, K1); 308 OP (27, FG, D, E, A, B, C, K1); 309 OP (28, FG, C, D, E, A, B, K1); 310 OP (29, FG, B, C, D, E, A, K1); 311 OP (30, FG, A, B, C, D, E, K1); 312 OP (31, FG, E, A, B, C, D, K1); 313 OP (32, FG, D, E, A, B, C, K1); 314 OP (33, FG, C, D, E, A, B, K1); 315 OP (34, FG, B, C, D, E, A, K1); 316 OP (35, FG, A, B, C, D, E, K1); 317 OP (36, FG, E, A, B, C, D, K1); 318 OP (37, FG, D, E, A, B, C, K1); 319 OP (38, FG, C, D, E, A, B, K1); 320 OP (39, FG, B, C, D, E, A, K1); 321 322 /* Steps 40 to 59. */ 323 OP (40, FH, A, B, C, D, E, K2); 324 OP (41, FH, E, A, B, C, D, K2); 325 OP (42, FH, D, E, A, B, C, K2); 326 OP (43, FH, C, D, E, A, B, K2); 327 OP (44, FH, B, C, D, E, A, K2); 328 OP (45, FH, A, B, C, D, E, K2); 329 OP (46, FH, E, A, B, C, D, K2); 330 OP (47, FH, D, E, A, B, C, K2); 331 OP (48, FH, C, D, E, A, B, K2); 332 OP (49, FH, B, C, D, E, A, K2); 333 OP (50, FH, A, B, C, D, E, K2); 334 OP (51, FH, E, A, B, C, D, K2); 335 OP (52, FH, D, E, A, B, C, K2); 336 OP (53, FH, C, D, E, A, B, K2); 337 OP (54, FH, B, C, D, E, A, K2); 338 OP (55, FH, A, B, C, D, E, K2); 339 OP (56, FH, E, A, B, C, D, K2); 340 OP (57, FH, D, E, A, B, C, K2); 341 OP (58, FH, C, D, E, A, B, K2); 342 OP (59, FH, B, C, D, E, A, K2); 343 344 /* Steps 60 to 79. */ 345 OP (60, FG, A, B, C, D, E, K3); 346 OP (61, FG, E, A, B, C, D, K3); 347 OP (62, FG, D, E, A, B, C, K3); 348 OP (63, FG, C, D, E, A, B, K3); 349 OP (64, FG, B, C, D, E, A, K3); 350 OP (65, FG, A, B, C, D, E, K3); 351 OP (66, FG, E, A, B, C, D, K3); 352 OP (67, FG, D, E, A, B, C, K3); 353 OP (68, FG, C, D, E, A, B, K3); 354 OP (69, FG, B, C, D, E, A, K3); 355 OP (70, FG, A, B, C, D, E, K3); 356 OP (71, FG, E, A, B, C, D, K3); 357 OP (72, FG, D, E, A, B, C, K3); 358 OP (73, FG, C, D, E, A, B, K3); 359 OP (74, FG, B, C, D, E, A, K3); 360 OP (75, FG, A, B, C, D, E, K3); 361 OP (76, FG, E, A, B, C, D, K3); 362 OP (77, FG, D, E, A, B, C, K3); 363 OP (78, FG, C, D, E, A, B, K3); 364 OP (79, FG, B, C, D, E, A, K3); 365 366 /* Add the starting values of the context. */ 367 A += A_save; 368 B += B_save; 369 C += C_save; 370 D += D_save; 371 E += E_save; 372 } 373 374 /* Put checksum in context given as argument. */ 375 ctx->A = A; 376 ctx->B = B; 377 ctx->C = C; 378 ctx->D = D; 379 ctx->E = E; 380 } 381
