146 lines
4.1 KiB
C
146 lines
4.1 KiB
C
/* sha256.c - Functions to compute SHA256 and SHA224 message digest of files or
|
|
memory blocks according to the NIST specification FIPS-180-2.
|
|
|
|
Copyright (C) 2005-2006, 2008-2022 Free Software Foundation, Inc.
|
|
|
|
This file is free software: you can redistribute it and/or modify
|
|
it under the terms of the GNU Lesser General Public License as
|
|
published by the Free Software Foundation; either version 2.1 of the
|
|
License, or (at your option) any later version.
|
|
|
|
This file 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 Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public License
|
|
along with this program. If not, see <https://www.gnu.org/licenses/>. */
|
|
|
|
/* Written by David Madore, considerably copypasting from
|
|
Scott G. Miller's sha1.c
|
|
*/
|
|
|
|
#include <config.h>
|
|
|
|
/* Specification. */
|
|
#if HAVE_OPENSSL_SHA256
|
|
# define GL_OPENSSL_INLINE _GL_EXTERN_INLINE
|
|
#endif
|
|
#include "sha256.h"
|
|
|
|
#include <stdlib.h>
|
|
|
|
#if USE_UNLOCKED_IO
|
|
# include "unlocked-io.h"
|
|
#endif
|
|
|
|
#include "af_alg.h"
|
|
|
|
#define BLOCKSIZE 32768
|
|
#if BLOCKSIZE % 64 != 0
|
|
# error "invalid BLOCKSIZE"
|
|
#endif
|
|
|
|
/* Compute message digest for bytes read from STREAM using algorithm ALG.
|
|
Write the message digest into RESBLOCK, which contains HASHLEN bytes.
|
|
The initial and finishing operations are INIT_CTX and FINISH_CTX.
|
|
Return zero if and only if successful. */
|
|
static int
|
|
shaxxx_stream (FILE *stream, char const *alg, void *resblock,
|
|
ssize_t hashlen, void (*init_ctx) (struct sha256_ctx *),
|
|
void *(*finish_ctx) (struct sha256_ctx *, void *))
|
|
{
|
|
switch (afalg_stream (stream, alg, resblock, hashlen))
|
|
{
|
|
case 0: return 0;
|
|
case -EIO: return 1;
|
|
}
|
|
|
|
char *buffer = malloc (BLOCKSIZE + 72);
|
|
if (!buffer)
|
|
return 1;
|
|
|
|
struct sha256_ctx ctx;
|
|
init_ctx (&ctx);
|
|
size_t sum;
|
|
|
|
/* Iterate over full file contents. */
|
|
while (1)
|
|
{
|
|
/* We read the file in blocks of BLOCKSIZE bytes. One call of the
|
|
computation function processes the whole buffer so that with the
|
|
next round of the loop another block can be read. */
|
|
size_t n;
|
|
sum = 0;
|
|
|
|
/* Read block. Take care for partial reads. */
|
|
while (1)
|
|
{
|
|
/* Either process a partial fread() from this loop,
|
|
or the fread() in afalg_stream may have gotten EOF.
|
|
We need to avoid a subsequent fread() as EOF may
|
|
not be sticky. For details of such systems, see:
|
|
https://sourceware.org/bugzilla/show_bug.cgi?id=1190 */
|
|
if (feof (stream))
|
|
goto process_partial_block;
|
|
|
|
n = fread (buffer + sum, 1, BLOCKSIZE - sum, stream);
|
|
|
|
sum += n;
|
|
|
|
if (sum == BLOCKSIZE)
|
|
break;
|
|
|
|
if (n == 0)
|
|
{
|
|
/* Check for the error flag IFF N == 0, so that we don't
|
|
exit the loop after a partial read due to e.g., EAGAIN
|
|
or EWOULDBLOCK. */
|
|
if (ferror (stream))
|
|
{
|
|
free (buffer);
|
|
return 1;
|
|
}
|
|
goto process_partial_block;
|
|
}
|
|
}
|
|
|
|
/* Process buffer with BLOCKSIZE bytes. Note that
|
|
BLOCKSIZE % 64 == 0
|
|
*/
|
|
sha256_process_block (buffer, BLOCKSIZE, &ctx);
|
|
}
|
|
|
|
process_partial_block:;
|
|
|
|
/* Process any remaining bytes. */
|
|
if (sum > 0)
|
|
sha256_process_bytes (buffer, sum, &ctx);
|
|
|
|
/* Construct result in desired memory. */
|
|
finish_ctx (&ctx, resblock);
|
|
free (buffer);
|
|
return 0;
|
|
}
|
|
|
|
int
|
|
sha256_stream (FILE *stream, void *resblock)
|
|
{
|
|
return shaxxx_stream (stream, "sha256", resblock, SHA256_DIGEST_SIZE,
|
|
sha256_init_ctx, sha256_finish_ctx);
|
|
}
|
|
|
|
int
|
|
sha224_stream (FILE *stream, void *resblock)
|
|
{
|
|
return shaxxx_stream (stream, "sha224", resblock, SHA224_DIGEST_SIZE,
|
|
sha224_init_ctx, sha224_finish_ctx);
|
|
}
|
|
|
|
/*
|
|
* Hey Emacs!
|
|
* Local Variables:
|
|
* coding: utf-8
|
|
* End:
|
|
*/
|