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2cdc6899 HY |
1 | /* |
2 | * GHASH: digest algorithm for GCM (Galois/Counter Mode). | |
3 | * | |
4 | * Copyright (c) 2007 Nokia Siemens Networks - Mikko Herranen <mh1@iki.fi> | |
5 | * Copyright (c) 2009 Intel Corp. | |
6 | * Author: Huang Ying <ying.huang@intel.com> | |
7 | * | |
8 | * The algorithm implementation is copied from gcm.c. | |
9 | * | |
10 | * This program is free software; you can redistribute it and/or modify it | |
11 | * under the terms of the GNU General Public License version 2 as published | |
12 | * by the Free Software Foundation. | |
13 | */ | |
14 | ||
15 | #include <crypto/algapi.h> | |
16 | #include <crypto/gf128mul.h> | |
a397ba82 | 17 | #include <crypto/ghash.h> |
2cdc6899 HY |
18 | #include <crypto/internal/hash.h> |
19 | #include <linux/crypto.h> | |
20 | #include <linux/init.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/module.h> | |
23 | ||
2cdc6899 HY |
24 | static int ghash_init(struct shash_desc *desc) |
25 | { | |
26 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); | |
27 | ||
28 | memset(dctx, 0, sizeof(*dctx)); | |
29 | ||
30 | return 0; | |
31 | } | |
32 | ||
33 | static int ghash_setkey(struct crypto_shash *tfm, | |
34 | const u8 *key, unsigned int keylen) | |
35 | { | |
36 | struct ghash_ctx *ctx = crypto_shash_ctx(tfm); | |
37 | ||
38 | if (keylen != GHASH_BLOCK_SIZE) { | |
39 | crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); | |
40 | return -EINVAL; | |
41 | } | |
42 | ||
43 | if (ctx->gf128) | |
44 | gf128mul_free_4k(ctx->gf128); | |
45 | ctx->gf128 = gf128mul_init_4k_lle((be128 *)key); | |
46 | if (!ctx->gf128) | |
47 | return -ENOMEM; | |
48 | ||
49 | return 0; | |
50 | } | |
51 | ||
52 | static int ghash_update(struct shash_desc *desc, | |
53 | const u8 *src, unsigned int srclen) | |
54 | { | |
55 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); | |
56 | struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm); | |
57 | u8 *dst = dctx->buffer; | |
58 | ||
59 | if (dctx->bytes) { | |
60 | int n = min(srclen, dctx->bytes); | |
61 | u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes); | |
62 | ||
63 | dctx->bytes -= n; | |
64 | srclen -= n; | |
65 | ||
66 | while (n--) | |
67 | *pos++ ^= *src++; | |
68 | ||
69 | if (!dctx->bytes) | |
70 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
71 | } | |
72 | ||
73 | while (srclen >= GHASH_BLOCK_SIZE) { | |
74 | crypto_xor(dst, src, GHASH_BLOCK_SIZE); | |
75 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
76 | src += GHASH_BLOCK_SIZE; | |
77 | srclen -= GHASH_BLOCK_SIZE; | |
78 | } | |
79 | ||
80 | if (srclen) { | |
81 | dctx->bytes = GHASH_BLOCK_SIZE - srclen; | |
82 | while (srclen--) | |
83 | *dst++ ^= *src++; | |
84 | } | |
85 | ||
86 | return 0; | |
87 | } | |
88 | ||
89 | static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx) | |
90 | { | |
91 | u8 *dst = dctx->buffer; | |
92 | ||
93 | if (dctx->bytes) { | |
94 | u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes); | |
95 | ||
96 | while (dctx->bytes--) | |
97 | *tmp++ ^= 0; | |
98 | ||
99 | gf128mul_4k_lle((be128 *)dst, ctx->gf128); | |
100 | } | |
101 | ||
102 | dctx->bytes = 0; | |
103 | } | |
104 | ||
105 | static int ghash_final(struct shash_desc *desc, u8 *dst) | |
106 | { | |
107 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); | |
108 | struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm); | |
109 | u8 *buf = dctx->buffer; | |
110 | ||
111 | ghash_flush(ctx, dctx); | |
112 | memcpy(dst, buf, GHASH_BLOCK_SIZE); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static void ghash_exit_tfm(struct crypto_tfm *tfm) | |
118 | { | |
119 | struct ghash_ctx *ctx = crypto_tfm_ctx(tfm); | |
120 | if (ctx->gf128) | |
121 | gf128mul_free_4k(ctx->gf128); | |
122 | } | |
123 | ||
124 | static struct shash_alg ghash_alg = { | |
125 | .digestsize = GHASH_DIGEST_SIZE, | |
126 | .init = ghash_init, | |
127 | .update = ghash_update, | |
128 | .final = ghash_final, | |
129 | .setkey = ghash_setkey, | |
130 | .descsize = sizeof(struct ghash_desc_ctx), | |
131 | .base = { | |
132 | .cra_name = "ghash", | |
133 | .cra_driver_name = "ghash-generic", | |
134 | .cra_priority = 100, | |
135 | .cra_flags = CRYPTO_ALG_TYPE_SHASH, | |
136 | .cra_blocksize = GHASH_BLOCK_SIZE, | |
137 | .cra_ctxsize = sizeof(struct ghash_ctx), | |
138 | .cra_module = THIS_MODULE, | |
2cdc6899 HY |
139 | .cra_exit = ghash_exit_tfm, |
140 | }, | |
141 | }; | |
142 | ||
143 | static int __init ghash_mod_init(void) | |
144 | { | |
145 | return crypto_register_shash(&ghash_alg); | |
146 | } | |
147 | ||
148 | static void __exit ghash_mod_exit(void) | |
149 | { | |
150 | crypto_unregister_shash(&ghash_alg); | |
151 | } | |
152 | ||
153 | module_init(ghash_mod_init); | |
154 | module_exit(ghash_mod_exit); | |
155 | ||
156 | MODULE_LICENSE("GPL"); | |
157 | MODULE_DESCRIPTION("GHASH Message Digest Algorithm"); | |
5d26a105 | 158 | MODULE_ALIAS_CRYPTO("ghash"); |
3e14dcf7 | 159 | MODULE_ALIAS_CRYPTO("ghash-generic"); |