chacha.c

 1// SPDX-License-Identifier: GPL-2.0-or-later
 2/*
 3 * The ChaCha stream cipher (RFC7539)
 4 *
 5 * Copyright (C) 2015 Martin Willi
 6 */
 7
 8#include <crypto/algapi.h> // for crypto_xor_cpy
 9#include <crypto/chacha.h>
10#include <linux/export.h>
11#include <linux/kernel.h>
12#include <linux/module.h>
13
14static void __maybe_unused
15chacha_crypt_generic(struct chacha_state *state, u8 *dst, const u8 *src,
16		     unsigned int bytes, int nrounds)
17{
18	/* aligned to potentially speed up crypto_xor() */
19	u8 stream[CHACHA_BLOCK_SIZE] __aligned(sizeof(long));
20
21	while (bytes >= CHACHA_BLOCK_SIZE) {
22		chacha_block_generic(state, stream, nrounds);
23		crypto_xor_cpy(dst, src, stream, CHACHA_BLOCK_SIZE);
24		bytes -= CHACHA_BLOCK_SIZE;
25		dst += CHACHA_BLOCK_SIZE;
26		src += CHACHA_BLOCK_SIZE;
27	}
28	if (bytes) {
29		chacha_block_generic(state, stream, nrounds);
30		crypto_xor_cpy(dst, src, stream, bytes);
31	}
32}
33
34#ifdef CONFIG_CRYPTO_LIB_CHACHA_ARCH
35#include "chacha.h" /* $(SRCARCH)/chacha.h */
36#else
37#define chacha_crypt_arch chacha_crypt_generic
38#define hchacha_block_arch hchacha_block_generic
39#endif
40
41void chacha_crypt(struct chacha_state *state, u8 *dst, const u8 *src,
42		  unsigned int bytes, int nrounds)
43{
44	chacha_crypt_arch(state, dst, src, bytes, nrounds);
45}
46EXPORT_SYMBOL_GPL(chacha_crypt);
47
48void hchacha_block(const struct chacha_state *state,
49		   u32 out[HCHACHA_OUT_WORDS], int nrounds)
50{
51	hchacha_block_arch(state, out, nrounds);
52}
53EXPORT_SYMBOL_GPL(hchacha_block);
54
55#ifdef chacha_mod_init_arch
56static int __init chacha_mod_init(void)
57{
58	chacha_mod_init_arch();
59	return 0;
60}
61subsys_initcall(chacha_mod_init);
62
63static void __exit chacha_mod_exit(void)
64{
65}
66module_exit(chacha_mod_exit);
67#endif
68
69MODULE_DESCRIPTION("ChaCha stream cipher (RFC7539)");
70MODULE_LICENSE("GPL");