416 lines
12 KiB
C
416 lines
12 KiB
C
/* sha1.c - Functions to compute SHA1 message digest of files or
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memory blocks according to the NIST specification FIPS-180-1.
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Copyright (C) 2000, 2001, 2003, 2004, 2005, 2006, 2008 Free Software
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Foundation, Inc.
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This program is free software; you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software Foundation,
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Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
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/* Written by Scott G. Miller
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Credits:
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Robert Klep <robert@ilse.nl> -- Expansion function fix
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*/
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#include <config.h>
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#include "sha1.h"
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#include <stddef.h>
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#include <string.h>
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#if USE_UNLOCKED_IO
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# include "unlocked-io.h"
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#endif
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#ifdef WORDS_BIGENDIAN
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# define SWAP(n) (n)
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#else
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# define SWAP(n) \
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(((n) << 24) | (((n) & 0xff00) << 8) | (((n) >> 8) & 0xff00) | ((n) >> 24))
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#endif
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#define BLOCKSIZE 4096
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#if BLOCKSIZE % 64 != 0
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# error "invalid BLOCKSIZE"
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#endif
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/* This array contains the bytes used to pad the buffer to the next
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64-byte boundary. (RFC 1321, 3.1: Step 1) */
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static const unsigned char fillbuf[64] = { 0x80, 0 /* , 0, 0, ... */ };
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/* Take a pointer to a 160 bit block of data (five 32 bit ints) and
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initialize it to the start constants of the SHA1 algorithm. This
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must be called before using hash in the call to sha1_hash. */
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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-bit 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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/* 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-bit 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 size = (bytes < 56) ? 64 / 4 : 64 * 2 / 4;
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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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/* Put the 64-bit file length in *bits* at the end of the buffer. */
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ctx->buffer[size - 2] = SWAP ((ctx->total[1] << 3) | (ctx->total[0] >> 29));
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ctx->buffer[size - 1] = SWAP (ctx->total[0] << 3);
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memcpy (&((char *) ctx->buffer)[bytes], fillbuf, (size - 2) * 4 - bytes);
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/* Process last bytes. */
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sha1_process_block (ctx->buffer, size * 4, ctx);
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return sha1_read_ctx (ctx, resbuf);
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}
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/* Compute SHA1 message digest for bytes read from STREAM. The
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resulting message digest number will be written into the 16 bytes
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beginning at RESBLOCK. */
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int
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sha1_stream (FILE *stream, void *resblock)
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{
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struct sha1_ctx ctx;
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char buffer[BLOCKSIZE + 72];
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size_t sum;
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/* Initialize the computation context. */
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sha1_init_ctx (&ctx);
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/* Iterate over full file contents. */
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while (1)
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{
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/* We read the file in blocks of BLOCKSIZE bytes. One call of the
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computation function processes the whole buffer so that with the
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next round of the loop another block can be read. */
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size_t n;
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sum = 0;
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/* Read block. Take care for partial reads. */
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while (1)
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{
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n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
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sum += n;
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if (sum == BLOCKSIZE)
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break;
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if (n == 0)
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{
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/* Check for the error flag IFF N == 0, so that we don't
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exit the loop after a partial read due to e.g., EAGAIN
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or EWOULDBLOCK. */
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if (ferror (stream))
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return 1;
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goto process_partial_block;
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}
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/* We've read at least one byte, so ignore errors. But always
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check for EOF, since feof may be true even though N > 0.
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Otherwise, we could end up calling fread after EOF. */
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if (feof (stream))
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goto process_partial_block;
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}
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/* Process buffer with BLOCKSIZE bytes. Note that
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BLOCKSIZE % 64 == 0
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*/
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sha1_process_block (buffer, BLOCKSIZE, &ctx);
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}
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process_partial_block:;
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/* Process any remaining bytes. */
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if (sum > 0)
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sha1_process_bytes (buffer, sum, &ctx);
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/* Construct result in desired memory. */
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sha1_finish_ctx (&ctx, resblock);
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return 0;
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}
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/* Compute SHA1 message digest for LEN bytes beginning at BUFFER. The
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result is always in little endian byte order, so that a byte-wise
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output yields to the wanted ASCII representation of the message
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digest. */
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void *
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sha1_buffer (const char *buffer, size_t len, void *resblock)
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{
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struct sha1_ctx ctx;
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/* Initialize the computation context. */
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sha1_init_ctx (&ctx);
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/* Process whole buffer but last len % 64 bytes. */
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sha1_process_bytes (buffer, len, &ctx);
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/* Put result in desired memory area. */
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return sha1_finish_ctx (&ctx, resblock);
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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 (&((char *) 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,
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&((char *) 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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# define alignof(type) offsetof (struct { char c; type x; }, x)
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# define UNALIGNED_P(p) (((size_t) p) % alignof (sha1_uint32) != 0)
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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 (&((char *) 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[16], 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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/* --- Code below is the primary difference between md5.c and sha1.c --- */
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/* SHA1 round constants */
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#define K1 0x5a827999
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#define K2 0x6ed9eba1
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#define K3 0x8f1bbcdc
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#define K4 0xca62c1d6
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/* Round functions. Note that F2 is the same as F4. */
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#define F1(B,C,D) ( D ^ ( B & ( C ^ D ) ) )
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#define F2(B,C,D) (B ^ C ^ D)
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#define F3(B,C,D) ( ( B & C ) | ( D & ( B | C ) ) )
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#define F4(B,C,D) (B ^ C ^ D)
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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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Most of this code comes from GnuPG's cipher/sha1.c. */
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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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const sha1_uint32 *words = (const sha1_uint32*) 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 x[16];
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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. RFC 1321 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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#define rol(x, n) (((x) << (n)) | ((sha1_uint32) (x) >> (32 - (n))))
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#define M(I) ( tm = x[I&0x0f] ^ x[(I-14)&0x0f] \
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^ x[(I-8)&0x0f] ^ x[(I-3)&0x0f] \
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, (x[I&0x0f] = rol(tm, 1)) )
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#define R(A,B,C,D,E,F,K,M) do { E += rol( A, 5 ) \
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+ F( B, C, D ) \
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+ K \
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+ M; \
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B = rol( B, 30 ); \
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} while(0)
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while (words < endp)
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{
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sha1_uint32 tm;
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int t;
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for (t = 0; t < 16; t++)
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{
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x[t] = SWAP (*words);
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words++;
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}
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R( a, b, c, d, e, F1, K1, x[ 0] );
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R( e, a, b, c, d, F1, K1, x[ 1] );
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R( d, e, a, b, c, F1, K1, x[ 2] );
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R( c, d, e, a, b, F1, K1, x[ 3] );
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R( b, c, d, e, a, F1, K1, x[ 4] );
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R( a, b, c, d, e, F1, K1, x[ 5] );
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R( e, a, b, c, d, F1, K1, x[ 6] );
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R( d, e, a, b, c, F1, K1, x[ 7] );
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R( c, d, e, a, b, F1, K1, x[ 8] );
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R( b, c, d, e, a, F1, K1, x[ 9] );
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R( a, b, c, d, e, F1, K1, x[10] );
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R( e, a, b, c, d, F1, K1, x[11] );
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R( d, e, a, b, c, F1, K1, x[12] );
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R( c, d, e, a, b, F1, K1, x[13] );
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R( b, c, d, e, a, F1, K1, x[14] );
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R( a, b, c, d, e, F1, K1, x[15] );
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R( e, a, b, c, d, F1, K1, M(16) );
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R( d, e, a, b, c, F1, K1, M(17) );
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R( c, d, e, a, b, F1, K1, M(18) );
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R( b, c, d, e, a, F1, K1, M(19) );
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R( a, b, c, d, e, F2, K2, M(20) );
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R( e, a, b, c, d, F2, K2, M(21) );
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R( d, e, a, b, c, F2, K2, M(22) );
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R( c, d, e, a, b, F2, K2, M(23) );
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R( b, c, d, e, a, F2, K2, M(24) );
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R( a, b, c, d, e, F2, K2, M(25) );
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R( e, a, b, c, d, F2, K2, M(26) );
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R( d, e, a, b, c, F2, K2, M(27) );
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R( c, d, e, a, b, F2, K2, M(28) );
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R( b, c, d, e, a, F2, K2, M(29) );
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R( a, b, c, d, e, F2, K2, M(30) );
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R( e, a, b, c, d, F2, K2, M(31) );
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R( d, e, a, b, c, F2, K2, M(32) );
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R( c, d, e, a, b, F2, K2, M(33) );
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R( b, c, d, e, a, F2, K2, M(34) );
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R( a, b, c, d, e, F2, K2, M(35) );
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R( e, a, b, c, d, F2, K2, M(36) );
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R( d, e, a, b, c, F2, K2, M(37) );
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R( c, d, e, a, b, F2, K2, M(38) );
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R( b, c, d, e, a, F2, K2, M(39) );
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R( a, b, c, d, e, F3, K3, M(40) );
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R( e, a, b, c, d, F3, K3, M(41) );
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R( d, e, a, b, c, F3, K3, M(42) );
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R( c, d, e, a, b, F3, K3, M(43) );
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R( b, c, d, e, a, F3, K3, M(44) );
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R( a, b, c, d, e, F3, K3, M(45) );
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R( e, a, b, c, d, F3, K3, M(46) );
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R( d, e, a, b, c, F3, K3, M(47) );
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R( c, d, e, a, b, F3, K3, M(48) );
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R( b, c, d, e, a, F3, K3, M(49) );
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R( a, b, c, d, e, F3, K3, M(50) );
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R( e, a, b, c, d, F3, K3, M(51) );
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R( d, e, a, b, c, F3, K3, M(52) );
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R( c, d, e, a, b, F3, K3, M(53) );
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R( b, c, d, e, a, F3, K3, M(54) );
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R( a, b, c, d, e, F3, K3, M(55) );
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R( e, a, b, c, d, F3, K3, M(56) );
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R( d, e, a, b, c, F3, K3, M(57) );
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R( c, d, e, a, b, F3, K3, M(58) );
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R( b, c, d, e, a, F3, K3, M(59) );
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R( a, b, c, d, e, F4, K4, M(60) );
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R( e, a, b, c, d, F4, K4, M(61) );
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R( d, e, a, b, c, F4, K4, M(62) );
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R( c, d, e, a, b, F4, K4, M(63) );
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R( b, c, d, e, a, F4, K4, M(64) );
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R( a, b, c, d, e, F4, K4, M(65) );
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R( e, a, b, c, d, F4, K4, M(66) );
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R( d, e, a, b, c, F4, K4, M(67) );
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R( c, d, e, a, b, F4, K4, M(68) );
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R( b, c, d, e, a, F4, K4, M(69) );
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R( a, b, c, d, e, F4, K4, M(70) );
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R( e, a, b, c, d, F4, K4, M(71) );
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R( d, e, a, b, c, F4, K4, M(72) );
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R( c, d, e, a, b, F4, K4, M(73) );
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R( b, c, d, e, a, F4, K4, M(74) );
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R( a, b, c, d, e, F4, K4, M(75) );
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R( e, a, b, c, d, F4, K4, M(76) );
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R( d, e, a, b, c, F4, K4, M(77) );
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R( c, d, e, a, b, F4, K4, M(78) );
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R( b, c, d, e, a, F4, K4, M(79) );
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a = ctx->A += a;
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b = ctx->B += b;
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c = ctx->C += c;
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d = ctx->D += d;
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e = ctx->E += e;
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}
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}
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