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![Mathias Krause](/assets/img/avatar_default.png)
Export the update function as crypto_sha1_update() to not have the need to reimplement the same algorithm for each SHA-1 implementation. This way the generic SHA-1 implementation can be used as fallback for other implementations that fail to run under certain circumstances, like the need for an FPU context while executing in IRQ context. Signed-off-by: Mathias Krause <minipli@googlemail.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
156 lines
3.5 KiB
C
156 lines
3.5 KiB
C
/*
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* Cryptographic API.
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*
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* SHA1 Secure Hash Algorithm.
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*
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* Derived from cryptoapi implementation, adapted for in-place
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* scatterlist interface.
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*
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* Copyright (c) Alan Smithee.
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* Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
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* Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
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*
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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 Free
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* Software Foundation; either version 2 of the License, or (at your option)
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* any later version.
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*
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*/
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#include <crypto/internal/hash.h>
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#include <linux/init.h>
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#include <linux/module.h>
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#include <linux/mm.h>
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#include <linux/cryptohash.h>
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#include <linux/types.h>
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#include <crypto/sha.h>
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#include <asm/byteorder.h>
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static int sha1_init(struct shash_desc *desc)
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{
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struct sha1_state *sctx = shash_desc_ctx(desc);
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*sctx = (struct sha1_state){
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.state = { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
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};
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return 0;
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}
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int crypto_sha1_update(struct shash_desc *desc, const u8 *data,
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unsigned int len)
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{
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struct sha1_state *sctx = shash_desc_ctx(desc);
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unsigned int partial, done;
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const u8 *src;
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partial = sctx->count % SHA1_BLOCK_SIZE;
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sctx->count += len;
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done = 0;
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src = data;
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if ((partial + len) >= SHA1_BLOCK_SIZE) {
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u32 temp[SHA_WORKSPACE_WORDS];
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if (partial) {
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done = -partial;
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memcpy(sctx->buffer + partial, data,
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done + SHA1_BLOCK_SIZE);
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src = sctx->buffer;
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}
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do {
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sha_transform(sctx->state, src, temp);
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done += SHA1_BLOCK_SIZE;
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src = data + done;
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} while (done + SHA1_BLOCK_SIZE <= len);
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memset(temp, 0, sizeof(temp));
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partial = 0;
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}
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memcpy(sctx->buffer + partial, src, len - done);
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return 0;
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}
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EXPORT_SYMBOL(crypto_sha1_update);
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/* Add padding and return the message digest. */
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static int sha1_final(struct shash_desc *desc, u8 *out)
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{
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struct sha1_state *sctx = shash_desc_ctx(desc);
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__be32 *dst = (__be32 *)out;
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u32 i, index, padlen;
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__be64 bits;
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static const u8 padding[64] = { 0x80, };
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bits = cpu_to_be64(sctx->count << 3);
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/* Pad out to 56 mod 64 */
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index = sctx->count & 0x3f;
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padlen = (index < 56) ? (56 - index) : ((64+56) - index);
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crypto_sha1_update(desc, padding, padlen);
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/* Append length */
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crypto_sha1_update(desc, (const u8 *)&bits, sizeof(bits));
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/* Store state in digest */
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for (i = 0; i < 5; i++)
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dst[i] = cpu_to_be32(sctx->state[i]);
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/* Wipe context */
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memset(sctx, 0, sizeof *sctx);
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return 0;
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}
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static int sha1_export(struct shash_desc *desc, void *out)
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{
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struct sha1_state *sctx = shash_desc_ctx(desc);
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memcpy(out, sctx, sizeof(*sctx));
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return 0;
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}
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static int sha1_import(struct shash_desc *desc, const void *in)
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{
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struct sha1_state *sctx = shash_desc_ctx(desc);
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memcpy(sctx, in, sizeof(*sctx));
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return 0;
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}
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static struct shash_alg alg = {
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.digestsize = SHA1_DIGEST_SIZE,
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.init = sha1_init,
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.update = crypto_sha1_update,
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.final = sha1_final,
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.export = sha1_export,
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.import = sha1_import,
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.descsize = sizeof(struct sha1_state),
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.statesize = sizeof(struct sha1_state),
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.base = {
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.cra_name = "sha1",
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.cra_driver_name= "sha1-generic",
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = SHA1_BLOCK_SIZE,
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.cra_module = THIS_MODULE,
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}
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};
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static int __init sha1_generic_mod_init(void)
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{
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return crypto_register_shash(&alg);
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}
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static void __exit sha1_generic_mod_fini(void)
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{
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crypto_unregister_shash(&alg);
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}
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module_init(sha1_generic_mod_init);
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module_exit(sha1_generic_mod_fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
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MODULE_ALIAS("sha1");
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