165 lines
3.6 KiB
C
165 lines
3.6 KiB
C
/*
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* GHASH: digest algorithm for GCM (Galois/Counter Mode).
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*
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* Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi>
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* Copyright (c) 2009 Intel Corp.
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* Author: Huang Ying <ying.huang@intel.com>
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*
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* The algorithm implementation is copied from gcm.c.
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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 version 2 as published
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* by the Free Software Foundation.
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*/
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#include <crypto/algapi.h>
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#include <crypto/gf128mul.h>
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#include <crypto/ghash.h>
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#include <crypto/internal/hash.h>
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#include <linux/crypto.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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static int ghash_init(struct shash_desc *desc)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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memset(dctx, 0, sizeof(*dctx));
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return 0;
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}
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static int ghash_setkey(struct crypto_shash *tfm,
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const u8 *key, unsigned int keylen)
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{
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struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
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be128 k;
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if (keylen != GHASH_BLOCK_SIZE) {
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crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
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return -EINVAL;
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}
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if (ctx->gf128)
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gf128mul_free_4k(ctx->gf128);
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BUILD_BUG_ON(sizeof(k) != GHASH_BLOCK_SIZE);
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memcpy(&k, key, GHASH_BLOCK_SIZE); /* avoid violating alignment rules */
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ctx->gf128 = gf128mul_init_4k_lle(&k);
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memzero_explicit(&k, GHASH_BLOCK_SIZE);
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if (!ctx->gf128)
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return -ENOMEM;
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return 0;
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}
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static int ghash_update(struct shash_desc *desc,
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const u8 *src, unsigned int srclen)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
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u8 *dst = dctx->buffer;
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if (dctx->bytes) {
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int n = min(srclen, dctx->bytes);
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u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
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dctx->bytes -= n;
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srclen -= n;
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while (n--)
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*pos++ ^= *src++;
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if (!dctx->bytes)
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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}
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while (srclen >= GHASH_BLOCK_SIZE) {
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crypto_xor(dst, src, GHASH_BLOCK_SIZE);
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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src += GHASH_BLOCK_SIZE;
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srclen -= GHASH_BLOCK_SIZE;
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}
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if (srclen) {
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dctx->bytes = GHASH_BLOCK_SIZE - srclen;
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while (srclen--)
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*dst++ ^= *src++;
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}
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return 0;
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}
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static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
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{
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u8 *dst = dctx->buffer;
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if (dctx->bytes) {
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u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
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while (dctx->bytes--)
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*tmp++ ^= 0;
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gf128mul_4k_lle((be128 *)dst, ctx->gf128);
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}
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dctx->bytes = 0;
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}
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static int ghash_final(struct shash_desc *desc, u8 *dst)
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{
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struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
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u8 *buf = dctx->buffer;
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ghash_flush(ctx, dctx);
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memcpy(dst, buf, GHASH_BLOCK_SIZE);
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return 0;
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}
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static void ghash_exit_tfm(struct crypto_tfm *tfm)
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{
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struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
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if (ctx->gf128)
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gf128mul_free_4k(ctx->gf128);
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}
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static struct shash_alg ghash_alg = {
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.digestsize = GHASH_DIGEST_SIZE,
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.init = ghash_init,
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.update = ghash_update,
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.final = ghash_final,
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.setkey = ghash_setkey,
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.descsize = sizeof(struct ghash_desc_ctx),
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.base = {
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.cra_name = "ghash",
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.cra_driver_name = "ghash-generic",
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.cra_priority = 100,
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.cra_blocksize = GHASH_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct ghash_ctx),
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.cra_module = THIS_MODULE,
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.cra_exit = ghash_exit_tfm,
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},
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};
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static int __init ghash_mod_init(void)
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{
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return crypto_register_shash(&ghash_alg);
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}
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static void __exit ghash_mod_exit(void)
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{
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crypto_unregister_shash(&ghash_alg);
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}
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module_init(ghash_mod_init);
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module_exit(ghash_mod_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
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MODULE_ALIAS_CRYPTO("ghash");
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MODULE_ALIAS_CRYPTO("ghash-generic");
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