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
14 static void __maybe_unused
chacha_crypt_generic(struct chacha_state * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)15 chacha_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
chacha_crypt(struct chacha_state * state,u8 * dst,const u8 * src,unsigned int bytes,int nrounds)41 void 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 }
46 EXPORT_SYMBOL_GPL(chacha_crypt);
47
hchacha_block(const struct chacha_state * state,u32 out[HCHACHA_OUT_WORDS],int nrounds)48 void hchacha_block(const struct chacha_state *state,
49 u32 out[HCHACHA_OUT_WORDS], int nrounds)
50 {
51 hchacha_block_arch(state, out, nrounds);
52 }
53 EXPORT_SYMBOL_GPL(hchacha_block);
54
55 #ifdef chacha_mod_init_arch
chacha_mod_init(void)56 static int __init chacha_mod_init(void)
57 {
58 chacha_mod_init_arch();
59 return 0;
60 }
61 subsys_initcall(chacha_mod_init);
62
chacha_mod_exit(void)63 static void __exit chacha_mod_exit(void)
64 {
65 }
66 module_exit(chacha_mod_exit);
67 #endif
68
69 MODULE_DESCRIPTION("ChaCha stream cipher (RFC7539)");
70 MODULE_LICENSE("GPL");
71