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974e4b75 TSH |
1 | /* |
2 | * Glue code for optimized assembly version of Salsa20. | |
3 | * | |
4 | * Copyright (c) 2007 Tan Swee Heng <thesweeheng@gmail.com> | |
5 | * | |
6 | * The assembly codes are public domain assembly codes written by Daniel. J. | |
7 | * Bernstein <djb@cr.yp.to>. The codes are modified to include indentation | |
8 | * and to remove extraneous comments and functions that are not needed. | |
9 | * - i586 version, renamed as salsa20-i586-asm_32.S | |
10 | * available from <http://cr.yp.to/snuffle/salsa20/x86-pm/salsa20.s> | |
9a7dafbb TSH |
11 | * - x86-64 version, renamed as salsa20-x86_64-asm_64.S |
12 | * available from <http://cr.yp.to/snuffle/salsa20/amd64-3/salsa20.s> | |
974e4b75 TSH |
13 | * |
14 | * This program is free software; you can redistribute it and/or modify it | |
15 | * under the terms of the GNU General Public License as published by the Free | |
16 | * Software Foundation; either version 2 of the License, or (at your option) | |
17 | * any later version. | |
18 | * | |
19 | */ | |
20 | ||
21 | #include <crypto/algapi.h> | |
22 | #include <linux/module.h> | |
23 | #include <linux/crypto.h> | |
24 | ||
25 | #define SALSA20_IV_SIZE 8U | |
26 | #define SALSA20_MIN_KEY_SIZE 16U | |
27 | #define SALSA20_MAX_KEY_SIZE 32U | |
28 | ||
974e4b75 TSH |
29 | struct salsa20_ctx |
30 | { | |
31 | u32 input[16]; | |
32 | }; | |
33 | ||
34 | asmlinkage void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, | |
35 | u32 keysize, u32 ivsize); | |
36 | asmlinkage void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv); | |
37 | asmlinkage void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, | |
38 | const u8 *src, u8 *dst, u32 bytes); | |
39 | ||
40 | static int setkey(struct crypto_tfm *tfm, const u8 *key, | |
41 | unsigned int keysize) | |
42 | { | |
43 | struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm); | |
44 | salsa20_keysetup(ctx, key, keysize*8, SALSA20_IV_SIZE*8); | |
45 | return 0; | |
46 | } | |
47 | ||
48 | static int encrypt(struct blkcipher_desc *desc, | |
49 | struct scatterlist *dst, struct scatterlist *src, | |
50 | unsigned int nbytes) | |
51 | { | |
52 | struct blkcipher_walk walk; | |
53 | struct crypto_blkcipher *tfm = desc->tfm; | |
54 | struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm); | |
55 | int err; | |
56 | ||
57 | blkcipher_walk_init(&walk, dst, src, nbytes); | |
58 | err = blkcipher_walk_virt_block(desc, &walk, 64); | |
59 | ||
60 | salsa20_ivsetup(ctx, walk.iv); | |
61 | ||
974e4b75 TSH |
62 | while (walk.nbytes >= 64) { |
63 | salsa20_encrypt_bytes(ctx, walk.src.virt.addr, | |
64 | walk.dst.virt.addr, | |
65 | walk.nbytes - (walk.nbytes % 64)); | |
66 | err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64); | |
67 | } | |
68 | ||
69 | if (walk.nbytes) { | |
70 | salsa20_encrypt_bytes(ctx, walk.src.virt.addr, | |
71 | walk.dst.virt.addr, walk.nbytes); | |
72 | err = blkcipher_walk_done(desc, &walk, 0); | |
73 | } | |
74 | ||
75 | return err; | |
76 | } | |
77 | ||
78 | static struct crypto_alg alg = { | |
79 | .cra_name = "salsa20", | |
80 | .cra_driver_name = "salsa20-asm", | |
81 | .cra_priority = 200, | |
82 | .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, | |
83 | .cra_type = &crypto_blkcipher_type, | |
84 | .cra_blocksize = 1, | |
85 | .cra_ctxsize = sizeof(struct salsa20_ctx), | |
86 | .cra_alignmask = 3, | |
87 | .cra_module = THIS_MODULE, | |
974e4b75 TSH |
88 | .cra_u = { |
89 | .blkcipher = { | |
90 | .setkey = setkey, | |
91 | .encrypt = encrypt, | |
92 | .decrypt = encrypt, | |
93 | .min_keysize = SALSA20_MIN_KEY_SIZE, | |
94 | .max_keysize = SALSA20_MAX_KEY_SIZE, | |
95 | .ivsize = SALSA20_IV_SIZE, | |
96 | } | |
97 | } | |
98 | }; | |
99 | ||
100 | static int __init init(void) | |
101 | { | |
102 | return crypto_register_alg(&alg); | |
103 | } | |
104 | ||
105 | static void __exit fini(void) | |
106 | { | |
107 | crypto_unregister_alg(&alg); | |
108 | } | |
109 | ||
110 | module_init(init); | |
111 | module_exit(fini); | |
112 | ||
113 | MODULE_LICENSE("GPL"); | |
114 | MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)"); | |
5d26a105 KC |
115 | MODULE_ALIAS_CRYPTO("salsa20"); |
116 | MODULE_ALIAS_CRYPTO("salsa20-asm"); |