157 lines
3.6 KiB
C
157 lines
3.6 KiB
C
/*
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* Accelerated GHASH implementation with ARMv8 PMULL instructions.
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*
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* Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.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 version 2 as published
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* by the Free Software Foundation.
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*/
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#include <asm/neon.h>
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#include <asm/unaligned.h>
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#include <crypto/internal/hash.h>
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#include <linux/cpufeature.h>
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#include <linux/crypto.h>
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#include <linux/module.h>
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MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
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MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
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MODULE_LICENSE("GPL v2");
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#define GHASH_BLOCK_SIZE 16
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#define GHASH_DIGEST_SIZE 16
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struct ghash_key {
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u64 a;
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u64 b;
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};
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struct ghash_desc_ctx {
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u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
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u8 buf[GHASH_BLOCK_SIZE];
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u32 count;
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};
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asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src,
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struct ghash_key const *k, const char *head);
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static int ghash_init(struct shash_desc *desc)
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{
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struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
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*ctx = (struct ghash_desc_ctx){};
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return 0;
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}
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static int ghash_update(struct shash_desc *desc, const u8 *src,
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unsigned int len)
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{
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struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
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unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
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ctx->count += len;
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if ((partial + len) >= GHASH_BLOCK_SIZE) {
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struct ghash_key *key = crypto_shash_ctx(desc->tfm);
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int blocks;
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if (partial) {
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int p = GHASH_BLOCK_SIZE - partial;
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memcpy(ctx->buf + partial, src, p);
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src += p;
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len -= p;
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}
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blocks = len / GHASH_BLOCK_SIZE;
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len %= GHASH_BLOCK_SIZE;
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kernel_neon_begin_partial(8);
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pmull_ghash_update(blocks, ctx->digest, src, key,
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partial ? ctx->buf : NULL);
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kernel_neon_end();
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src += blocks * GHASH_BLOCK_SIZE;
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partial = 0;
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}
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if (len)
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memcpy(ctx->buf + partial, src, len);
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return 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 *ctx = shash_desc_ctx(desc);
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unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;
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if (partial) {
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struct ghash_key *key = crypto_shash_ctx(desc->tfm);
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memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);
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kernel_neon_begin_partial(8);
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pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
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kernel_neon_end();
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}
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put_unaligned_be64(ctx->digest[1], dst);
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put_unaligned_be64(ctx->digest[0], dst + 8);
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*ctx = (struct ghash_desc_ctx){};
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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 *inkey, unsigned int keylen)
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{
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struct ghash_key *key = crypto_shash_ctx(tfm);
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u64 a, b;
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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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/* perform multiplication by 'x' in GF(2^128) */
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b = get_unaligned_be64(inkey);
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a = get_unaligned_be64(inkey + 8);
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key->a = (a << 1) | (b >> 63);
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key->b = (b << 1) | (a >> 63);
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if (b >> 63)
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key->b ^= 0xc200000000000000UL;
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return 0;
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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-ce",
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.cra_priority = 200,
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.cra_flags = CRYPTO_ALG_TYPE_SHASH,
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.cra_blocksize = GHASH_BLOCK_SIZE,
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.cra_ctxsize = sizeof(struct ghash_key),
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.cra_module = THIS_MODULE,
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},
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};
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static int __init ghash_ce_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_ce_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_cpu_feature_match(PMULL, ghash_ce_mod_init);
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module_exit(ghash_ce_mod_exit);
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