arm64: capabilities: Prepare for fine grained capabilities
[linux-2.6-microblaze.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/ghash.h>
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
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,
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");
158 MODULE_ALIAS_CRYPTO("ghash");
159 MODULE_ALIAS_CRYPTO("ghash-generic");