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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 | ||
29 | // use the ECRYPT_* function names | |
30 | #define salsa20_keysetup ECRYPT_keysetup | |
31 | #define salsa20_ivsetup ECRYPT_ivsetup | |
32 | #define salsa20_encrypt_bytes ECRYPT_encrypt_bytes | |
33 | ||
34 | struct salsa20_ctx | |
35 | { | |
36 | u32 input[16]; | |
37 | }; | |
38 | ||
39 | asmlinkage void salsa20_keysetup(struct salsa20_ctx *ctx, const u8 *k, | |
40 | u32 keysize, u32 ivsize); | |
41 | asmlinkage void salsa20_ivsetup(struct salsa20_ctx *ctx, const u8 *iv); | |
42 | asmlinkage void salsa20_encrypt_bytes(struct salsa20_ctx *ctx, | |
43 | const u8 *src, u8 *dst, u32 bytes); | |
44 | ||
45 | static int setkey(struct crypto_tfm *tfm, const u8 *key, | |
46 | unsigned int keysize) | |
47 | { | |
48 | struct salsa20_ctx *ctx = crypto_tfm_ctx(tfm); | |
49 | salsa20_keysetup(ctx, key, keysize*8, SALSA20_IV_SIZE*8); | |
50 | return 0; | |
51 | } | |
52 | ||
53 | static int encrypt(struct blkcipher_desc *desc, | |
54 | struct scatterlist *dst, struct scatterlist *src, | |
55 | unsigned int nbytes) | |
56 | { | |
57 | struct blkcipher_walk walk; | |
58 | struct crypto_blkcipher *tfm = desc->tfm; | |
59 | struct salsa20_ctx *ctx = crypto_blkcipher_ctx(tfm); | |
60 | int err; | |
61 | ||
62 | blkcipher_walk_init(&walk, dst, src, nbytes); | |
63 | err = blkcipher_walk_virt_block(desc, &walk, 64); | |
64 | ||
65 | salsa20_ivsetup(ctx, walk.iv); | |
66 | ||
67 | if (likely(walk.nbytes == nbytes)) | |
68 | { | |
69 | salsa20_encrypt_bytes(ctx, walk.src.virt.addr, | |
70 | walk.dst.virt.addr, nbytes); | |
71 | return blkcipher_walk_done(desc, &walk, 0); | |
72 | } | |
73 | ||
74 | while (walk.nbytes >= 64) { | |
75 | salsa20_encrypt_bytes(ctx, walk.src.virt.addr, | |
76 | walk.dst.virt.addr, | |
77 | walk.nbytes - (walk.nbytes % 64)); | |
78 | err = blkcipher_walk_done(desc, &walk, walk.nbytes % 64); | |
79 | } | |
80 | ||
81 | if (walk.nbytes) { | |
82 | salsa20_encrypt_bytes(ctx, walk.src.virt.addr, | |
83 | walk.dst.virt.addr, walk.nbytes); | |
84 | err = blkcipher_walk_done(desc, &walk, 0); | |
85 | } | |
86 | ||
87 | return err; | |
88 | } | |
89 | ||
90 | static struct crypto_alg alg = { | |
91 | .cra_name = "salsa20", | |
92 | .cra_driver_name = "salsa20-asm", | |
93 | .cra_priority = 200, | |
94 | .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, | |
95 | .cra_type = &crypto_blkcipher_type, | |
96 | .cra_blocksize = 1, | |
97 | .cra_ctxsize = sizeof(struct salsa20_ctx), | |
98 | .cra_alignmask = 3, | |
99 | .cra_module = THIS_MODULE, | |
100 | .cra_list = LIST_HEAD_INIT(alg.cra_list), | |
101 | .cra_u = { | |
102 | .blkcipher = { | |
103 | .setkey = setkey, | |
104 | .encrypt = encrypt, | |
105 | .decrypt = encrypt, | |
106 | .min_keysize = SALSA20_MIN_KEY_SIZE, | |
107 | .max_keysize = SALSA20_MAX_KEY_SIZE, | |
108 | .ivsize = SALSA20_IV_SIZE, | |
109 | } | |
110 | } | |
111 | }; | |
112 | ||
113 | static int __init init(void) | |
114 | { | |
115 | return crypto_register_alg(&alg); | |
116 | } | |
117 | ||
118 | static void __exit fini(void) | |
119 | { | |
120 | crypto_unregister_alg(&alg); | |
121 | } | |
122 | ||
123 | module_init(init); | |
124 | module_exit(fini); | |
125 | ||
126 | MODULE_LICENSE("GPL"); | |
127 | MODULE_DESCRIPTION ("Salsa20 stream cipher algorithm (optimized assembly version)"); | |
128 | MODULE_ALIAS("salsa20"); | |
129 | MODULE_ALIAS("salsa20-asm"); |