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linux/crypto/chacha_generic.c
Thomas Gleixner 2874c5fd28 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152
Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation either version 2 of the license or at
  your option any later version

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:32 -07:00

212 lines
5.8 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/chacha.h>
#include <crypto/internal/skcipher.h>
#include <linux/module.h>
static void chacha_docrypt(u32 *state, u8 *dst, const u8 *src,
unsigned int bytes, int nrounds)
{
/* aligned to potentially speed up crypto_xor() */
u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
while (bytes >= CHACHA_BLOCK_SIZE) {
chacha_block(state, stream, nrounds);
crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
bytes -= CHACHA_BLOCK_SIZE;
dst += CHACHA_BLOCK_SIZE;
src += CHACHA_BLOCK_SIZE;
}
if (bytes) {
chacha_block(state, stream, nrounds);
crypto_xor_cpy(dst, src, stream, bytes);
}
}
static int chacha_stream_xor(struct skcipher_request *req,
struct chacha_ctx *ctx, u8 *iv)
{
struct skcipher_walk walk;
u32 state[16];
int err;
err = skcipher_walk_virt(&walk, req, false);
crypto_chacha_init(state, ctx, iv);
while (walk.nbytes > 0) {
unsigned int nbytes = walk.nbytes;
if (nbytes < walk.total)
nbytes = round_down(nbytes, CHACHA_BLOCK_SIZE);
chacha_docrypt(state, walk.dst.virt.addr, walk.src.virt.addr,
nbytes, ctx->nrounds);
err = skcipher_walk_done(&walk, walk.nbytes - nbytes);
}
return err;
}
void crypto_chacha_init(u32 *state, struct chacha_ctx *ctx, u8 *iv)
{
state[0] = 0x61707865; /* "expa" */
state[1] = 0x3320646e; /* "nd 3" */
state[2] = 0x79622d32; /* "2-by" */
state[3] = 0x6b206574; /* "te k" */
state[4] = ctx->key[0];
state[5] = ctx->key[1];
state[6] = ctx->key[2];
state[7] = ctx->key[3];
state[8] = ctx->key[4];
state[9] = ctx->key[5];
state[10] = ctx->key[6];
state[11] = ctx->key[7];
state[12] = get_unaligned_le32(iv + 0);
state[13] = get_unaligned_le32(iv + 4);
state[14] = get_unaligned_le32(iv + 8);
state[15] = get_unaligned_le32(iv + 12);
}
EXPORT_SYMBOL_GPL(crypto_chacha_init);
static int chacha_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize, int nrounds)
{
struct chacha_ctx *ctx = crypto_skcipher_ctx(tfm);
int i;
if (keysize != CHACHA_KEY_SIZE)
return -EINVAL;
for (i = 0; i < ARRAY_SIZE(ctx->key); i++)
ctx->key[i] = get_unaligned_le32(key + i * sizeof(u32));
ctx->nrounds = nrounds;
return 0;
}
int crypto_chacha20_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
return chacha_setkey(tfm, key, keysize, 20);
}
EXPORT_SYMBOL_GPL(crypto_chacha20_setkey);
int crypto_chacha12_setkey(struct crypto_skcipher *tfm, const u8 *key,
unsigned int keysize)
{
return chacha_setkey(tfm, key, keysize, 12);
}
EXPORT_SYMBOL_GPL(crypto_chacha12_setkey);
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);
}
EXPORT_SYMBOL_GPL(crypto_chacha_crypt);
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 */
crypto_chacha_init(state, ctx, req->iv);
hchacha_block(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);
}
EXPORT_SYMBOL_GPL(crypto_xchacha_crypt);
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 = crypto_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 = crypto_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 = crypto_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");