Revert "ARM: tegra: tegratab: dummy change"
[linux-2.6.git] / crypto / ghash-generic.c
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>
17 #include <crypto/internal/hash.h>
18 #include <linux/crypto.h>
19 #include <linux/init.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22
23 #define GHASH_BLOCK_SIZE        16
24 #define GHASH_DIGEST_SIZE       16
25
26 struct ghash_ctx {
27         struct gf128mul_4k *gf128;
28 };
29
30 struct ghash_desc_ctx {
31         u8 buffer[GHASH_BLOCK_SIZE];
32         u32 bytes;
33 };
34
35 static int ghash_init(struct shash_desc *desc)
36 {
37         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
38
39         memset(dctx, 0, sizeof(*dctx));
40
41         return 0;
42 }
43
44 static int ghash_setkey(struct crypto_shash *tfm,
45                         const u8 *key, unsigned int keylen)
46 {
47         struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
48
49         if (keylen != GHASH_BLOCK_SIZE) {
50                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
51                 return -EINVAL;
52         }
53
54         if (ctx->gf128)
55                 gf128mul_free_4k(ctx->gf128);
56         ctx->gf128 = gf128mul_init_4k_lle((be128 *)key);
57         if (!ctx->gf128)
58                 return -ENOMEM;
59
60         return 0;
61 }
62
63 static int ghash_update(struct shash_desc *desc,
64                          const u8 *src, unsigned int srclen)
65 {
66         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
67         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
68         u8 *dst = dctx->buffer;
69
70         if (!ctx->gf128)
71                 return -ENOKEY;
72
73         if (dctx->bytes) {
74                 int n = min(srclen, dctx->bytes);
75                 u8 *pos = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
76
77                 dctx->bytes -= n;
78                 srclen -= n;
79
80                 while (n--)
81                         *pos++ ^= *src++;
82
83                 if (!dctx->bytes)
84                         gf128mul_4k_lle((be128 *)dst, ctx->gf128);
85         }
86
87         while (srclen >= GHASH_BLOCK_SIZE) {
88                 crypto_xor(dst, src, GHASH_BLOCK_SIZE);
89                 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
90                 src += GHASH_BLOCK_SIZE;
91                 srclen -= GHASH_BLOCK_SIZE;
92         }
93
94         if (srclen) {
95                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
96                 while (srclen--)
97                         *dst++ ^= *src++;
98         }
99
100         return 0;
101 }
102
103 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
104 {
105         u8 *dst = dctx->buffer;
106
107         if (dctx->bytes) {
108                 u8 *tmp = dst + (GHASH_BLOCK_SIZE - dctx->bytes);
109
110                 while (dctx->bytes--)
111                         *tmp++ ^= 0;
112
113                 gf128mul_4k_lle((be128 *)dst, ctx->gf128);
114         }
115
116         dctx->bytes = 0;
117 }
118
119 static int ghash_final(struct shash_desc *desc, u8 *dst)
120 {
121         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
122         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
123         u8 *buf = dctx->buffer;
124
125         if (!ctx->gf128)
126                 return -ENOKEY;
127
128         ghash_flush(ctx, dctx);
129         memcpy(dst, buf, GHASH_BLOCK_SIZE);
130
131         return 0;
132 }
133
134 static void ghash_exit_tfm(struct crypto_tfm *tfm)
135 {
136         struct ghash_ctx *ctx = crypto_tfm_ctx(tfm);
137         if (ctx->gf128)
138                 gf128mul_free_4k(ctx->gf128);
139 }
140
141 static struct shash_alg ghash_alg = {
142         .digestsize     = GHASH_DIGEST_SIZE,
143         .init           = ghash_init,
144         .update         = ghash_update,
145         .final          = ghash_final,
146         .setkey         = ghash_setkey,
147         .descsize       = sizeof(struct ghash_desc_ctx),
148         .base           = {
149                 .cra_name               = "ghash",
150                 .cra_driver_name        = "ghash-generic",
151                 .cra_priority           = 100,
152                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
153                 .cra_blocksize          = GHASH_BLOCK_SIZE,
154                 .cra_ctxsize            = sizeof(struct ghash_ctx),
155                 .cra_module             = THIS_MODULE,
156                 .cra_list               = LIST_HEAD_INIT(ghash_alg.base.cra_list),
157                 .cra_exit               = ghash_exit_tfm,
158         },
159 };
160
161 static int __init ghash_mod_init(void)
162 {
163         return crypto_register_shash(&ghash_alg);
164 }
165
166 static void __exit ghash_mod_exit(void)
167 {
168         crypto_unregister_shash(&ghash_alg);
169 }
170
171 module_init(ghash_mod_init);
172 module_exit(ghash_mod_exit);
173
174 MODULE_LICENSE("GPL");
175 MODULE_DESCRIPTION("GHASH Message Digest Algorithm");
176 MODULE_ALIAS("ghash");