124 lines
3.5 KiB
C
124 lines
3.5 KiB
C
/* sm3.c - Functions to compute SM3 message digest of files or memory blocks
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according to the specification GM/T 004-2012 Cryptographic Hash Algorithm
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SM3, published by State Encryption Management Bureau, China.
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SM3 cryptographic hash algorithm.
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<http://www.sca.gov.cn/sca/xwdt/2010-12/17/content_1002389.shtml>
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Copyright (C) 2017-2022 Free Software Foundation, Inc.
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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 the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file 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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Jia Zhang <qianyue.zj@alibaba-inc.com>, 2017,
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considerably copypasting from David Madore's sha256.c */
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#include <config.h>
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/* Specification. */
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#if HAVE_OPENSSL_SM3
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# define GL_OPENSSL_INLINE _GL_EXTERN_INLINE
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#endif
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#include "sm3.h"
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#include <stdlib.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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#define BLOCKSIZE 32768
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#if BLOCKSIZE % 64 != 0
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# error "invalid BLOCKSIZE"
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#endif
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/* Compute SM3 message digest for bytes read from STREAM. The
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resulting message digest number will be written into the 32 bytes
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beginning at RESBLOCK. */
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int
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sm3_stream (FILE *stream, void *resblock)
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{
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struct sm3_ctx ctx;
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size_t sum;
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char *buffer = malloc (BLOCKSIZE + 72);
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if (!buffer)
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return 1;
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/* Initialize the computation context. */
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sm3_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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{
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free (buffer);
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return 1;
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}
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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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sm3_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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sm3_process_bytes (buffer, sum, &ctx);
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/* Construct result in desired memory. */
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sm3_finish_ctx (&ctx, resblock);
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free (buffer);
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return 0;
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}
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/*
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* Hey Emacs!
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* Local Variables:
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* coding: utf-8
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* End:
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*/
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