diff options
Diffstat (limited to 'sha1.c')
| -rw-r--r-- | sha1.c | 340 |
1 files changed, 340 insertions, 0 deletions
@@ -0,0 +1,340 @@ +/* sha1.c - Functions to compute SHA1 message digest of files or + memory blocks according to the NIST specification FIPS-180-1. + + Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2008 Free Software + Foundation, Inc. + + This program is free software; you can redistribute it and/or modify it + under the terms of the GNU General Public License as published by the + Free Software Foundation; either version 2, or (at your option) any + later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program; if not, write to the Free Software Foundation, + Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ + +/* Written by Scott G. Miller + Credits: + Robert Klep <robert@ilse.nl> -- Expansion function fix +*/ + +#include "sha1.h" + +#include <stddef.h> +#include <string.h> +#include <endian.h> + +#if __BYTE_ORDER == __BIG_ENDIAN +# define SWAP(n) (n) +#else +# define SWAP(n) \ + (((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24)) +#endif + +/* This array contains the bytes used to pad the buffer to the next + 64-byte boundary. (RFC 1321, 3.1: Step 1) */ +static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ }; + + +/* Take a pointer to a 160 bit block of data (five 32 bit ints) and + initialize it to the start constants of the SHA1 algorithm. This + must be called before using hash in the call to sha1_hash. */ +void +sha1_init_ctx (struct sha1_ctx *ctx) +{ + ctx->A = 0x67452301; + ctx->B = 0xefcdab89; + ctx->C = 0x98badcfe; + ctx->D = 0x10325476; + ctx->E = 0xc3d2e1f0; + + ctx->total[0] = ctx->total[1] = 0; + ctx->buflen = 0; +} + +/* Put result from CTX in first 20 bytes following RESBUF. The result + must be in little endian byte order. + + IMPORTANT: On some systems it is required that RESBUF is correctly + aligned for a 32-bit value. */ +void * +sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf) +{ + ((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A); + ((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B); + ((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C); + ((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D); + ((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E); + + return resbuf; +} + +/* Process the remaining bytes in the internal buffer and the usual + prolog according to the standard and write the result to RESBUF. + + IMPORTANT: On some systems it is required that RESBUF is correctly + aligned for a 32-bit value. */ +void * +sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf) +{ + /* Take yet unprocessed bytes into account. */ + sha1_uint32 bytes = ctx->buflen; + size_t size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4; + + /* Now count remaining bytes. */ + ctx->total[0] += bytes; + if (ctx->total[0] < bytes) + ++ctx->total[1]; + + /* Put the 64-bit file length in *bits* at the end of the buffer. */ + ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29)); + ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3); + + memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes); + + /* Process last bytes. */ + sha1_process_block (ctx->buffer, size * 4, ctx); + + return sha1_read_ctx (ctx, resbuf); +} + +/* Compute SHA1 message digest for LEN bytes beginning at BUFFER. The + result is always in little endian byte order, so that a byte-wise + output yields to the wanted ASCII representation of the message + digest. */ +void * +sha1_buffer (const char *buffer, size_t len, void *resblock) +{ + struct sha1_ctx ctx; + + /* Initialize the computation context. */ + sha1_init_ctx (&ctx); + + /* Process whole buffer but last len % 64 bytes. */ + sha1_process_bytes (buffer, len, &ctx); + + /* Put result in desired memory area. */ + return sha1_finish_ctx (&ctx, resblock); +} + +void +sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx) +{ + /* When we already have some bits in our internal buffer concatenate + both inputs first. */ + if (ctx->buflen != 0) + { + size_t left_over = ctx->buflen; + size_t add = 128 - left_over > len ? len : 128 - left_over; + + memcpy (&((char *) ctx->buffer)[left_over], buffer, add); + ctx->buflen += add; + + if (ctx->buflen > 64) + { + sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx); + + ctx->buflen &= 63; + /* The regions in the following copy operation cannot overlap. */ + memcpy (ctx->buffer, + &((char *) ctx->buffer)[(left_over + add) & ~63], + ctx->buflen); + } + + buffer = (const char *) buffer + add; + len -= add; + } + + /* Process available complete blocks. */ + if (len >= 64) + { +#if !_STRING_ARCH_unaligned +# define alignof(type) offsetof (struct { char c; type x; }, x) +# define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0) + if (UNALIGNED_P (buffer)) + while (len > 64) + { + sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx); + buffer = (const char *) buffer + 64; + len -= 64; + } + else +#endif + { + sha1_process_block (buffer, len & ~63, ctx); + buffer = (const char *) buffer + (len & ~63); + len &= 63; + } + } + + /* Move remaining bytes in internal buffer. */ + if (len > 0) + { + size_t left_over = ctx->buflen; + + memcpy (&((char *) ctx->buffer)[left_over], buffer, len); + left_over += len; + if (left_over >= 64) + { + sha1_process_block (ctx->buffer, 64, ctx); + left_over -= 64; + memcpy (ctx->buffer, &ctx->buffer[16], left_over); + } + ctx->buflen = left_over; + } +} + +/* --- Code below is the primary difference between md5.c and sha1.c --- */ + +/* SHA1 round constants */ +#define K1 0x5a827999 +#define K2 0x6ed9eba1 +#define K3 0x8f1bbcdc +#define K4 0xca62c1d6 + +/* Round functions. Note that F2 is the same as F4. */ +#define F1(B,C,D) ( D ^ ( B & ( C ^ D ) ) ) +#define F2(B,C,D) (B ^ C ^ D) +#define F3(B,C,D) ( ( B & C ) | ( D & ( B | C ) ) ) +#define F4(B,C,D) (B ^ C ^ D) + +/* Process LEN bytes of BUFFER, accumulating context into CTX. + It is assumed that LEN % 64 == 0. + Most of this code comes from GnuPG's cipher/sha1.c. */ + +void +sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx) +{ + const sha1_uint32 *words = (const sha1_uint32*) buffer; + size_t nwords = len / sizeof (sha1_uint32); + const sha1_uint32 *endp = words + nwords; + sha1_uint32 x[16]; + sha1_uint32 a = ctx->A; + sha1_uint32 b = ctx->B; + sha1_uint32 c = ctx->C; + sha1_uint32 d = ctx->D; + sha1_uint32 e = ctx->E; + + /* First increment the byte count. RFC 1321 specifies the possible + length of the file up to 2^64 bits. Here we only compute the + number of bytes. Do a double word increment. */ + ctx->total[0] += len; + if (ctx->total[0] < len) + ++ctx->total[1]; + +#define rol(x, n) (((x) << (n)) | ((sha1_uint32) (x) >> (32 - (n)))) + +#define M(I) ( tm = x[I&0x0f] ^ x[(I-14)&0x0f] \ + ^ x[(I-8)&0x0f] ^ x[(I-3)&0x0f] \ + , (x[I&0x0f] = rol(tm, 1)) ) + +#define R(A,B,C,D,E,F,K,M) do { E += rol( A, 5 ) \ + + F( B, C, D ) \ + + K \ + + M; \ + B = rol( B, 30 ); \ + } while(0) + + while (words < endp) + { + sha1_uint32 tm; + int t; + for (t = 0; t < 16; t++) + { + x[t] = SWAP (*words); + words++; + } + + R( a, b, c, d, e, F1, K1, x[ 0] ); + R( e, a, b, c, d, F1, K1, x[ 1] ); + R( d, e, a, b, c, F1, K1, x[ 2] ); + R( c, d, e, a, b, F1, K1, x[ 3] ); + R( b, c, d, e, a, F1, K1, x[ 4] ); + R( a, b, c, d, e, F1, K1, x[ 5] ); + R( e, a, b, c, d, F1, K1, x[ 6] ); + R( d, e, a, b, c, F1, K1, x[ 7] ); + R( c, d, e, a, b, F1, K1, x[ 8] ); + R( b, c, d, e, a, F1, K1, x[ 9] ); + R( a, b, c, d, e, F1, K1, x[10] ); + R( e, a, b, c, d, F1, K1, x[11] ); + R( d, e, a, b, c, F1, K1, x[12] ); + R( c, d, e, a, b, F1, K1, x[13] ); + R( b, c, d, e, a, F1, K1, x[14] ); + R( a, b, c, d, e, F1, K1, x[15] ); + R( e, a, b, c, d, F1, K1, M(16) ); + R( d, e, a, b, c, F1, K1, M(17) ); + R( c, d, e, a, b, F1, K1, M(18) ); + R( b, c, d, e, a, F1, K1, M(19) ); + R( a, b, c, d, e, F2, K2, M(20) ); + R( e, a, b, c, d, F2, K2, M(21) ); + R( d, e, a, b, c, F2, K2, M(22) ); + R( c, d, e, a, b, F2, K2, M(23) ); + R( b, c, d, e, a, F2, K2, M(24) ); + R( a, b, c, d, e, F2, K2, M(25) ); + R( e, a, b, c, d, F2, K2, M(26) ); + R( d, e, a, b, c, F2, K2, M(27) ); + R( c, d, e, a, b, F2, K2, M(28) ); + R( b, c, d, e, a, F2, K2, M(29) ); + R( a, b, c, d, e, F2, K2, M(30) ); + R( e, a, b, c, d, F2, K2, M(31) ); + R( d, e, a, b, c, F2, K2, M(32) ); + R( c, d, e, a, b, F2, K2, M(33) ); + R( b, c, d, e, a, F2, K2, M(34) ); + R( a, b, c, d, e, F2, K2, M(35) ); + R( e, a, b, c, d, F2, K2, M(36) ); + R( d, e, a, b, c, F2, K2, M(37) ); + R( c, d, e, a, b, F2, K2, M(38) ); + R( b, c, d, e, a, F2, K2, M(39) ); + R( a, b, c, d, e, F3, K3, M(40) ); + R( e, a, b, c, d, F3, K3, M(41) ); + R( d, e, a, b, c, F3, K3, M(42) ); + R( c, d, e, a, b, F3, K3, M(43) ); + R( b, c, d, e, a, F3, K3, M(44) ); + R( a, b, c, d, e, F3, K3, M(45) ); + R( e, a, b, c, d, F3, K3, M(46) ); + R( d, e, a, b, c, F3, K3, M(47) ); + R( c, d, e, a, b, F3, K3, M(48) ); + R( b, c, d, e, a, F3, K3, M(49) ); + R( a, b, c, d, e, F3, K3, M(50) ); + R( e, a, b, c, d, F3, K3, M(51) ); + R( d, e, a, b, c, F3, K3, M(52) ); + R( c, d, e, a, b, F3, K3, M(53) ); + R( b, c, d, e, a, F3, K3, M(54) ); + R( a, b, c, d, e, F3, K3, M(55) ); + R( e, a, b, c, d, F3, K3, M(56) ); + R( d, e, a, b, c, F3, K3, M(57) ); + R( c, d, e, a, b, F3, K3, M(58) ); + R( b, c, d, e, a, F3, K3, M(59) ); + R( a, b, c, d, e, F4, K4, M(60) ); + R( e, a, b, c, d, F4, K4, M(61) ); + R( d, e, a, b, c, F4, K4, M(62) ); + R( c, d, e, a, b, F4, K4, M(63) ); + R( b, c, d, e, a, F4, K4, M(64) ); + R( a, b, c, d, e, F4, K4, M(65) ); + R( e, a, b, c, d, F4, K4, M(66) ); + R( d, e, a, b, c, F4, K4, M(67) ); + R( c, d, e, a, b, F4, K4, M(68) ); + R( b, c, d, e, a, F4, K4, M(69) ); + R( a, b, c, d, e, F4, K4, M(70) ); + R( e, a, b, c, d, F4, K4, M(71) ); + R( d, e, a, b, c, F4, K4, M(72) ); + R( c, d, e, a, b, F4, K4, M(73) ); + R( b, c, d, e, a, F4, K4, M(74) ); + R( a, b, c, d, e, F4, K4, M(75) ); + R( e, a, b, c, d, F4, K4, M(76) ); + R( d, e, a, b, c, F4, K4, M(77) ); + R( c, d, e, a, b, F4, K4, M(78) ); + R( b, c, d, e, a, F4, K4, M(79) ); + + a = ctx->A += a; + b = ctx->B += b; + c = ctx->C += c; + d = ctx->D += d; + e = ctx->E += e; + } +} |