140 lines
3.9 KiB
C
140 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
|
|
/*
|
|
* ChaCha and XChaCha stream ciphers, including ChaCha20 (RFC7539)
|
|
*
|
|
* Copyright (C) 2015 Martin Willi
|
|
* Copyright (C) 2018 Google LLC
|
|
*/
|
|
|
|
#include <asm/unaligned.h>
|
|
#include <crypto/algapi.h>
|
|
#include <crypto/internal/chacha.h>
|
|
#include <crypto/internal/skcipher.h>
|
|
#include <linux/module.h>
|
|
|
|
static int chacha_stream_xor(struct skcipher_request *req,
|
|
const struct chacha_ctx *ctx, const u8 *iv)
|
|
{
|
|
struct skcipher_walk walk;
|
|
u32 state[16];
|
|
int err;
|
|
|
|
err = skcipher_walk_virt(&walk, req, false);
|
|
|
|
chacha_init_generic(state, ctx->key, iv);
|
|
|
|
while (walk.nbytes > 0) {
|
|
unsigned int nbytes = walk.nbytes;
|
|
|
|
if (nbytes < walk.total)
|
|
nbytes = round_down(nbytes, CHACHA_BLOCK_SIZE);
|
|
|
|
chacha_crypt_generic(state, walk.dst.virt.addr,
|
|
walk.src.virt.addr, nbytes, ctx->nrounds);
|
|
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
|
|
}
|
|
|
|
return err;
|
|
}
|
|
|
|
static int crypto_chacha_crypt(struct skcipher_request *req)
|
|
{
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
|
|
|
|
return chacha_stream_xor(req, ctx, req->iv);
|
|
}
|
|
|
|
static int crypto_xchacha_crypt(struct skcipher_request *req)
|
|
{
|
|
struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req);
|
|
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
|
|
struct chacha_ctx subctx;
|
|
u32 state[16];
|
|
u8 real_iv[16];
|
|
|
|
/* Compute the subkey given the original key and first 128 nonce bits */
|
|
chacha_init_generic(state, ctx->key, req->iv);
|
|
hchacha_block_generic(state, subctx.key, ctx->nrounds);
|
|
subctx.nrounds = ctx->nrounds;
|
|
|
|
/* Build the real IV */
|
|
memcpy(&real_iv[0], req->iv + 24, 8); /* stream position */
|
|
memcpy(&real_iv[8], req->iv + 16, 8); /* remaining 64 nonce bits */
|
|
|
|
/* Generate the stream and XOR it with the data */
|
|
return chacha_stream_xor(req, &subctx, real_iv);
|
|
}
|
|
|
|
static struct skcipher_alg algs[] = {
|
|
{
|
|
.base.cra_name = "chacha20",
|
|
.base.cra_driver_name = "chacha20-generic",
|
|
.base.cra_priority = 100,
|
|
.base.cra_blocksize = 1,
|
|
.base.cra_ctxsize = sizeof(struct chacha_ctx),
|
|
.base.cra_module = THIS_MODULE,
|
|
|
|
.min_keysize = CHACHA_KEY_SIZE,
|
|
.max_keysize = CHACHA_KEY_SIZE,
|
|
.ivsize = CHACHA_IV_SIZE,
|
|
.chunksize = CHACHA_BLOCK_SIZE,
|
|
.setkey = chacha20_setkey,
|
|
.encrypt = crypto_chacha_crypt,
|
|
.decrypt = crypto_chacha_crypt,
|
|
}, {
|
|
.base.cra_name = "xchacha20",
|
|
.base.cra_driver_name = "xchacha20-generic",
|
|
.base.cra_priority = 100,
|
|
.base.cra_blocksize = 1,
|
|
.base.cra_ctxsize = sizeof(struct chacha_ctx),
|
|
.base.cra_module = THIS_MODULE,
|
|
|
|
.min_keysize = CHACHA_KEY_SIZE,
|
|
.max_keysize = CHACHA_KEY_SIZE,
|
|
.ivsize = XCHACHA_IV_SIZE,
|
|
.chunksize = CHACHA_BLOCK_SIZE,
|
|
.setkey = chacha20_setkey,
|
|
.encrypt = crypto_xchacha_crypt,
|
|
.decrypt = crypto_xchacha_crypt,
|
|
}, {
|
|
.base.cra_name = "xchacha12",
|
|
.base.cra_driver_name = "xchacha12-generic",
|
|
.base.cra_priority = 100,
|
|
.base.cra_blocksize = 1,
|
|
.base.cra_ctxsize = sizeof(struct chacha_ctx),
|
|
.base.cra_module = THIS_MODULE,
|
|
|
|
.min_keysize = CHACHA_KEY_SIZE,
|
|
.max_keysize = CHACHA_KEY_SIZE,
|
|
.ivsize = XCHACHA_IV_SIZE,
|
|
.chunksize = CHACHA_BLOCK_SIZE,
|
|
.setkey = chacha12_setkey,
|
|
.encrypt = crypto_xchacha_crypt,
|
|
.decrypt = crypto_xchacha_crypt,
|
|
}
|
|
};
|
|
|
|
static int __init chacha_generic_mod_init(void)
|
|
{
|
|
return crypto_register_skciphers(algs, ARRAY_SIZE(algs));
|
|
}
|
|
|
|
static void __exit chacha_generic_mod_fini(void)
|
|
{
|
|
crypto_unregister_skciphers(algs, ARRAY_SIZE(algs));
|
|
}
|
|
|
|
subsys_initcall(chacha_generic_mod_init);
|
|
module_exit(chacha_generic_mod_fini);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_AUTHOR("Martin Willi <martin@strongswan.org>");
|
|
MODULE_DESCRIPTION("ChaCha and XChaCha stream ciphers (generic)");
|
|
MODULE_ALIAS_CRYPTO("chacha20");
|
|
MODULE_ALIAS_CRYPTO("chacha20-generic");
|
|
MODULE_ALIAS_CRYPTO("xchacha20");
|
|
MODULE_ALIAS_CRYPTO("xchacha20-generic");
|
|
MODULE_ALIAS_CRYPTO("xchacha12");
|
|
MODULE_ALIAS_CRYPTO("xchacha12-generic");
|