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d21be3b4e1
(from https://sourceware.org/elfutils/, GPL/LGPL licensed)
381 lines
11 KiB
C
381 lines
11 KiB
C
/* Functions to compute SHA1 message digest of files or memory blocks.
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according to the definition of SHA1 in FIPS 180-1 from April 1997.
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Copyright (C) 2008-2011, 2015 Red Hat, Inc.
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This file is part of elfutils.
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Written by Ulrich Drepper <drepper@redhat.com>, 2008.
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This file is free software; you can redistribute it and/or modify
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it under the terms of either
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* the GNU Lesser General Public License as published by the Free
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Software Foundation; either version 3 of the License, or (at
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your option) any later version
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or
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* the GNU General Public License as published by the Free
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Software Foundation; either version 2 of the License, or (at
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your option) any later version
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or both in parallel, as here.
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elfutils is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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You should have received copies of the GNU General Public License and
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the GNU Lesser General Public License along with this program. If
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not, see <http://www.gnu.org/licenses/>. */
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#ifdef HAVE_CONFIG_H
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# include <config.h>
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#endif
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#include <stdlib.h>
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#include <string.h>
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#include <sys/types.h>
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#include "sha1.h"
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#include "system.h"
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#define SWAP(n) BE32 (n)
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/* This array contains the bytes used to pad the buffer to the next
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64-byte boundary. */
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static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
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/* Initialize structure containing state of computation. */
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void
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sha1_init_ctx (struct sha1_ctx *ctx)
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{
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ctx->A = 0x67452301;
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ctx->B = 0xefcdab89;
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ctx->C = 0x98badcfe;
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ctx->D = 0x10325476;
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ctx->E = 0xc3d2e1f0;
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ctx->total[0] = ctx->total[1] = 0;
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ctx->buflen = 0;
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}
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/* Put result from CTX in first 20 bytes following RESBUF. The result
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must be in little endian byte order.
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IMPORTANT: On some systems it is required that RESBUF is correctly
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aligned for a 32 bits value. */
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void *
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sha1_read_ctx (const struct sha1_ctx *ctx, void *resbuf)
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{
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((sha1_uint32 *) resbuf)[0] = SWAP (ctx->A);
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((sha1_uint32 *) resbuf)[1] = SWAP (ctx->B);
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((sha1_uint32 *) resbuf)[2] = SWAP (ctx->C);
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((sha1_uint32 *) resbuf)[3] = SWAP (ctx->D);
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((sha1_uint32 *) resbuf)[4] = SWAP (ctx->E);
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return resbuf;
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}
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static void
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be64_copy (char *dest, uint64_t x)
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{
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for (size_t i = 8; i-- > 0; x >>= 8)
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dest[i] = (uint8_t) x;
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}
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/* Process the remaining bytes in the internal buffer and the usual
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prolog according to the standard and write the result to RESBUF.
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IMPORTANT: On some systems it is required that RESBUF is correctly
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aligned for a 32 bits value. */
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void *
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sha1_finish_ctx (struct sha1_ctx *ctx, void *resbuf)
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{
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/* Take yet unprocessed bytes into account. */
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sha1_uint32 bytes = ctx->buflen;
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size_t pad;
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/* Now count remaining bytes. */
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ctx->total[0] += bytes;
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if (ctx->total[0] < bytes)
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++ctx->total[1];
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pad = bytes >= 56 ? 64 + 56 - bytes : 56 - bytes;
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memcpy (&ctx->buffer[bytes], fillbuf, pad);
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/* Put the 64-bit file length in *bits* at the end of the buffer. */
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const uint64_t bit_length = ((ctx->total[0] << 3)
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+ ((uint64_t) ((ctx->total[1] << 3) |
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(ctx->total[0] >> 29)) << 32));
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be64_copy (&ctx->buffer[bytes + pad], bit_length);
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/* Process last bytes. */
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sha1_process_block (ctx->buffer, bytes + pad + 8, ctx);
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return sha1_read_ctx (ctx, resbuf);
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}
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void
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sha1_process_bytes (const void *buffer, size_t len, struct sha1_ctx *ctx)
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{
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/* When we already have some bits in our internal buffer concatenate
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both inputs first. */
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if (ctx->buflen != 0)
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{
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size_t left_over = ctx->buflen;
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size_t add = 128 - left_over > len ? len : 128 - left_over;
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memcpy (&ctx->buffer[left_over], buffer, add);
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ctx->buflen += add;
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if (ctx->buflen > 64)
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{
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sha1_process_block (ctx->buffer, ctx->buflen & ~63, ctx);
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ctx->buflen &= 63;
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/* The regions in the following copy operation cannot overlap. */
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memcpy (ctx->buffer, &ctx->buffer[(left_over + add) & ~63],
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ctx->buflen);
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}
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buffer = (const char *) buffer + add;
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len -= add;
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}
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/* Process available complete blocks. */
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if (len >= 64)
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{
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#if !_STRING_ARCH_unaligned
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/* To check alignment gcc has an appropriate operator. Other
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compilers don't. */
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# if __GNUC__ >= 2
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# define UNALIGNED_P(p) (((sha1_uintptr) p) % __alignof__ (sha1_uint32) != 0)
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# else
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# define UNALIGNED_P(p) (((sha1_uintptr) p) % sizeof (sha1_uint32) != 0)
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# endif
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if (UNALIGNED_P (buffer))
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while (len > 64)
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{
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sha1_process_block (memcpy (ctx->buffer, buffer, 64), 64, ctx);
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buffer = (const char *) buffer + 64;
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len -= 64;
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}
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else
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#endif
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{
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sha1_process_block (buffer, len & ~63, ctx);
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buffer = (const char *) buffer + (len & ~63);
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len &= 63;
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}
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}
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/* Move remaining bytes in internal buffer. */
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if (len > 0)
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{
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size_t left_over = ctx->buflen;
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memcpy (&ctx->buffer[left_over], buffer, len);
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left_over += len;
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if (left_over >= 64)
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{
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sha1_process_block (ctx->buffer, 64, ctx);
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left_over -= 64;
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memcpy (ctx->buffer, &ctx->buffer[64], left_over);
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}
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ctx->buflen = left_over;
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}
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}
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/* These are the four functions used in the four steps of the SHA1 algorithm
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and defined in the FIPS 180-1. */
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/* #define FF(b, c, d) ((b & c) | (~b & d)) */
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#define FF(b, c, d) (d ^ (b & (c ^ d)))
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#define FG(b, c, d) (b ^ c ^ d)
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/* define FH(b, c, d) ((b & c) | (b & d) | (c & d)) */
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#define FH(b, c, d) (((b | c) & d) | (b & c))
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/* It is unfortunate that C does not provide an operator for cyclic
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rotation. Hope the C compiler is smart enough. */
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#define CYCLIC(w, s) (((w) << s) | ((w) >> (32 - s)))
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/* Magic constants. */
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#define K0 0x5a827999
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#define K1 0x6ed9eba1
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#define K2 0x8f1bbcdc
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#define K3 0xca62c1d6
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/* Process LEN bytes of BUFFER, accumulating context into CTX.
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It is assumed that LEN % 64 == 0. */
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void
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sha1_process_block (const void *buffer, size_t len, struct sha1_ctx *ctx)
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{
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sha1_uint32 computed_words[16];
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#define W(i) computed_words[(i) % 16]
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const sha1_uint32 *words = buffer;
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size_t nwords = len / sizeof (sha1_uint32);
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const sha1_uint32 *endp = words + nwords;
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sha1_uint32 A = ctx->A;
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sha1_uint32 B = ctx->B;
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sha1_uint32 C = ctx->C;
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sha1_uint32 D = ctx->D;
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sha1_uint32 E = ctx->E;
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/* First increment the byte count. FIPS 180-1 specifies the possible
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length of the file up to 2^64 bits. Here we only compute the
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number of bytes. Do a double word increment. */
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ctx->total[0] += len;
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if (ctx->total[0] < len)
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++ctx->total[1];
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/* Process all bytes in the buffer with 64 bytes in each round of
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the loop. */
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while (words < endp)
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{
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sha1_uint32 A_save = A;
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sha1_uint32 B_save = B;
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sha1_uint32 C_save = C;
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sha1_uint32 D_save = D;
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sha1_uint32 E_save = E;
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/* First round: using the given function, the context and a constant
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the next context is computed. Because the algorithms processing
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unit is a 32-bit word and it is determined to work on words in
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little endian byte order we perhaps have to change the byte order
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before the computation. */
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#define OP(i, a, b, c, d, e) \
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do \
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{ \
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W (i) = SWAP (*words); \
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e = CYCLIC (a, 5) + FF (b, c, d) + e + W (i) + K0; \
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++words; \
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b = CYCLIC (b, 30); \
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} \
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while (0)
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/* Steps 0 to 15. */
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OP (0, A, B, C, D, E);
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OP (1, E, A, B, C, D);
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OP (2, D, E, A, B, C);
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OP (3, C, D, E, A, B);
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OP (4, B, C, D, E, A);
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OP (5, A, B, C, D, E);
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OP (6, E, A, B, C, D);
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OP (7, D, E, A, B, C);
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OP (8, C, D, E, A, B);
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OP (9, B, C, D, E, A);
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OP (10, A, B, C, D, E);
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OP (11, E, A, B, C, D);
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OP (12, D, E, A, B, C);
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OP (13, C, D, E, A, B);
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OP (14, B, C, D, E, A);
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OP (15, A, B, C, D, E);
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/* For the remaining 64 steps we have a more complicated
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computation of the input data-derived values. Redefine the
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macro to take an additional second argument specifying the
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function to use and a new last parameter for the magic
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constant. */
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#undef OP
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#define OP(i, f, a, b, c, d, e, K) \
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do \
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{ \
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W (i) = CYCLIC (W (i - 3) ^ W (i - 8) ^ W (i - 14) ^ W (i - 16), 1);\
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e = CYCLIC (a, 5) + f (b, c, d) + e + W (i) + K; \
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b = CYCLIC (b, 30); \
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} \
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while (0)
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/* Steps 16 to 19. */
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OP (16, FF, E, A, B, C, D, K0);
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OP (17, FF, D, E, A, B, C, K0);
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OP (18, FF, C, D, E, A, B, K0);
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OP (19, FF, B, C, D, E, A, K0);
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/* Steps 20 to 39. */
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OP (20, FG, A, B, C, D, E, K1);
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OP (21, FG, E, A, B, C, D, K1);
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OP (22, FG, D, E, A, B, C, K1);
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OP (23, FG, C, D, E, A, B, K1);
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OP (24, FG, B, C, D, E, A, K1);
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OP (25, FG, A, B, C, D, E, K1);
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OP (26, FG, E, A, B, C, D, K1);
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OP (27, FG, D, E, A, B, C, K1);
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OP (28, FG, C, D, E, A, B, K1);
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OP (29, FG, B, C, D, E, A, K1);
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OP (30, FG, A, B, C, D, E, K1);
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OP (31, FG, E, A, B, C, D, K1);
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OP (32, FG, D, E, A, B, C, K1);
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OP (33, FG, C, D, E, A, B, K1);
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OP (34, FG, B, C, D, E, A, K1);
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OP (35, FG, A, B, C, D, E, K1);
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OP (36, FG, E, A, B, C, D, K1);
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OP (37, FG, D, E, A, B, C, K1);
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OP (38, FG, C, D, E, A, B, K1);
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OP (39, FG, B, C, D, E, A, K1);
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/* Steps 40 to 59. */
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OP (40, FH, A, B, C, D, E, K2);
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OP (41, FH, E, A, B, C, D, K2);
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OP (42, FH, D, E, A, B, C, K2);
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OP (43, FH, C, D, E, A, B, K2);
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OP (44, FH, B, C, D, E, A, K2);
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OP (45, FH, A, B, C, D, E, K2);
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OP (46, FH, E, A, B, C, D, K2);
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OP (47, FH, D, E, A, B, C, K2);
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OP (48, FH, C, D, E, A, B, K2);
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OP (49, FH, B, C, D, E, A, K2);
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OP (50, FH, A, B, C, D, E, K2);
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OP (51, FH, E, A, B, C, D, K2);
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OP (52, FH, D, E, A, B, C, K2);
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OP (53, FH, C, D, E, A, B, K2);
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OP (54, FH, B, C, D, E, A, K2);
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OP (55, FH, A, B, C, D, E, K2);
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OP (56, FH, E, A, B, C, D, K2);
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OP (57, FH, D, E, A, B, C, K2);
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OP (58, FH, C, D, E, A, B, K2);
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OP (59, FH, B, C, D, E, A, K2);
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/* Steps 60 to 79. */
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OP (60, FG, A, B, C, D, E, K3);
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OP (61, FG, E, A, B, C, D, K3);
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OP (62, FG, D, E, A, B, C, K3);
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OP (63, FG, C, D, E, A, B, K3);
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OP (64, FG, B, C, D, E, A, K3);
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OP (65, FG, A, B, C, D, E, K3);
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OP (66, FG, E, A, B, C, D, K3);
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OP (67, FG, D, E, A, B, C, K3);
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OP (68, FG, C, D, E, A, B, K3);
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OP (69, FG, B, C, D, E, A, K3);
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OP (70, FG, A, B, C, D, E, K3);
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OP (71, FG, E, A, B, C, D, K3);
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OP (72, FG, D, E, A, B, C, K3);
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OP (73, FG, C, D, E, A, B, K3);
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OP (74, FG, B, C, D, E, A, K3);
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OP (75, FG, A, B, C, D, E, K3);
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OP (76, FG, E, A, B, C, D, K3);
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OP (77, FG, D, E, A, B, C, K3);
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OP (78, FG, C, D, E, A, B, K3);
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OP (79, FG, B, C, D, E, A, K3);
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/* Add the starting values of the context. */
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A += A_save;
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B += B_save;
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C += C_save;
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D += D_save;
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E += E_save;
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}
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/* Put checksum in context given as argument. */
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ctx->A = A;
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ctx->B = B;
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ctx->C = C;
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ctx->D = D;
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ctx->E = E;
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}
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