140 строки
3.1 KiB
C
140 строки
3.1 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 <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/crypto.h>
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#include <linux/cryptohash.h>
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#include <linux/types.h>
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#include <asm/scatterlist.h>
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#include <asm/byteorder.h>
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#define SHA1_DIGEST_SIZE 20
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#define SHA1_HMAC_BLOCK_SIZE 64
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struct sha1_ctx {
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u64 count;
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u32 state[5];
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u8 buffer[64];
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};
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static void sha1_init(struct crypto_tfm *tfm)
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{
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struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
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static const struct sha1_ctx initstate = {
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0,
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{ 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0 },
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{ 0, }
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};
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*sctx = initstate;
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}
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static void sha1_update(struct crypto_tfm *tfm, const u8 *data,
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unsigned int len)
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{
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struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
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unsigned int partial, done;
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const u8 *src;
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partial = sctx->count & 0x3f;
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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) > 63) {
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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, done + 64);
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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 += 64;
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src = data + done;
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} while (done + 63 < 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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}
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/* Add padding and return the message digest. */
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static void sha1_final(struct crypto_tfm *tfm, u8 *out)
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{
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struct sha1_ctx *sctx = crypto_tfm_ctx(tfm);
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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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sha1_update(tfm, padding, padlen);
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/* Append length */
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sha1_update(tfm, (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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}
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static struct crypto_alg alg = {
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.cra_name = "sha1",
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.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
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.cra_blocksize = SHA1_HMAC_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct sha1_ctx),
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.cra_module = THIS_MODULE,
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.cra_alignmask = 3,
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.cra_list = LIST_HEAD_INIT(alg.cra_list),
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.cra_u = { .digest = {
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.dia_digestsize = SHA1_DIGEST_SIZE,
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.dia_init = sha1_init,
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.dia_update = sha1_update,
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.dia_final = sha1_final } }
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};
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static int __init init(void)
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{
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return crypto_register_alg(&alg);
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}
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static void __exit fini(void)
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{
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crypto_unregister_alg(&alg);
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}
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module_init(init);
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module_exit(fini);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");
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