cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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chacha_generic.c (3964B)

      1// SPDX-License-Identifier: GPL-2.0-or-later
      2/*
      3 * ChaCha and XChaCha stream ciphers, including ChaCha20 (RFC7539)
      4 *
      5 * Copyright (C) 2015 Martin Willi
      6 * Copyright (C) 2018 Google LLC
      7 */
      8
      9#include <asm/unaligned.h>
     10#include <crypto/algapi.h>
     11#include <crypto/internal/chacha.h>
     12#include <crypto/internal/skcipher.h>
     13#include <linux/module.h>
     14
     15static int chacha_stream_xor(struct skcipher_request *req,
     16			     const struct chacha_ctx *ctx, const u8 *iv)
     17{
     18	struct skcipher_walk walk;
     19	u32 state[16];
     20	int err;
     21
     22	err = skcipher_walk_virt(&walk, req, false);
     23
     24	chacha_init_generic(state, ctx->key, iv);
     25
     26	while (walk.nbytes > 0) {
     27		unsigned int nbytes = walk.nbytes;
     28
     29		if (nbytes < walk.total)
     30			nbytes = round_down(nbytes, CHACHA_BLOCK_SIZE);
     31
     32		chacha_crypt_generic(state, walk.dst.virt.addr,
     33				     walk.src.virt.addr, nbytes, ctx->nrounds);
     34		err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
     35	}
     36
     37	return err;
     38}
     39
     40static int crypto_chacha_crypt(struct skcipher_request *req)
     41{
     42	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
     43	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
     44
     45	return chacha_stream_xor(req, ctx, req->iv);
     46}
     47
     48static int crypto_xchacha_crypt(struct skcipher_request *req)
     49{
     50	struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
     51	struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
     52	struct chacha_ctx subctx;
     53	u32 state[16];
     54	u8 real_iv[16];
     55
     56	/* Compute the subkey given the original key and first 128 nonce bits */
     57	chacha_init_generic(state, ctx->key, req->iv);
     58	hchacha_block_generic(state, subctx.key, ctx->nrounds);
     59	subctx.nrounds = ctx->nrounds;
     60
     61	/* Build the real IV */
     62	memcpy(&real_iv[0], req->iv + 24, 8); /* stream position */
     63	memcpy(&real_iv[8], req->iv + 16, 8); /* remaining 64 nonce bits */
     64
     65	/* Generate the stream and XOR it with the data */
     66	return chacha_stream_xor(req, &subctx, real_iv);
     67}
     68
     69static struct skcipher_alg algs[] = {
     70	{
     71		.base.cra_name		= "chacha20",
     72		.base.cra_driver_name	= "chacha20-generic",
     73		.base.cra_priority	= 100,
     74		.base.cra_blocksize	= 1,
     75		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
     76		.base.cra_module	= THIS_MODULE,
     77
     78		.min_keysize		= CHACHA_KEY_SIZE,
     79		.max_keysize		= CHACHA_KEY_SIZE,
     80		.ivsize			= CHACHA_IV_SIZE,
     81		.chunksize		= CHACHA_BLOCK_SIZE,
     82		.setkey			= chacha20_setkey,
     83		.encrypt		= crypto_chacha_crypt,
     84		.decrypt		= crypto_chacha_crypt,
     85	}, {
     86		.base.cra_name		= "xchacha20",
     87		.base.cra_driver_name	= "xchacha20-generic",
     88		.base.cra_priority	= 100,
     89		.base.cra_blocksize	= 1,
     90		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
     91		.base.cra_module	= THIS_MODULE,
     92
     93		.min_keysize		= CHACHA_KEY_SIZE,
     94		.max_keysize		= CHACHA_KEY_SIZE,
     95		.ivsize			= XCHACHA_IV_SIZE,
     96		.chunksize		= CHACHA_BLOCK_SIZE,
     97		.setkey			= chacha20_setkey,
     98		.encrypt		= crypto_xchacha_crypt,
     99		.decrypt		= crypto_xchacha_crypt,
    100	}, {
    101		.base.cra_name		= "xchacha12",
    102		.base.cra_driver_name	= "xchacha12-generic",
    103		.base.cra_priority	= 100,
    104		.base.cra_blocksize	= 1,
    105		.base.cra_ctxsize	= sizeof(struct chacha_ctx),
    106		.base.cra_module	= THIS_MODULE,
    107
    108		.min_keysize		= CHACHA_KEY_SIZE,
    109		.max_keysize		= CHACHA_KEY_SIZE,
    110		.ivsize			= XCHACHA_IV_SIZE,
    111		.chunksize		= CHACHA_BLOCK_SIZE,
    112		.setkey			= chacha12_setkey,
    113		.encrypt		= crypto_xchacha_crypt,
    114		.decrypt		= crypto_xchacha_crypt,
    115	}
    116};
    117
    118static int __init chacha_generic_mod_init(void)
    119{
    120	return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
    121}
    122
    123static void __exit chacha_generic_mod_fini(void)
    124{
    125	crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
    126}
    127
    128subsys_initcall(chacha_generic_mod_init);
    129module_exit(chacha_generic_mod_fini);
    130
    131MODULE_LICENSE("GPL");
    132MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
    133MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (generic)");
    134MODULE_ALIAS_CRYPTO("chacha20");
    135MODULE_ALIAS_CRYPTO("chacha20-generic");
    136MODULE_ALIAS_CRYPTO("xchacha20");
    137MODULE_ALIAS_CRYPTO("xchacha20-generic");
    138MODULE_ALIAS_CRYPTO("xchacha12");
    139MODULE_ALIAS_CRYPTO("xchacha12-generic");