Merge git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6.git] / arch / s390 / crypto / ghash_s390.c
1 /*
2  * Cryptographic API.
3  *
4  * s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
5  *
6  * Copyright IBM Corp. 2011
7  * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
8  */
9
10 #include <crypto/internal/hash.h>
11 #include <linux/module.h>
12
13 #include "crypt_s390.h"
14
15 #define GHASH_BLOCK_SIZE        16
16 #define GHASH_DIGEST_SIZE       16
17
18 struct ghash_ctx {
19         u8 icv[16];
20         u8 key[16];
21 };
22
23 struct ghash_desc_ctx {
24         u8 buffer[GHASH_BLOCK_SIZE];
25         u32 bytes;
26 };
27
28 static int ghash_init(struct shash_desc *desc)
29 {
30         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
31
32         memset(dctx, 0, sizeof(*dctx));
33
34         return 0;
35 }
36
37 static int ghash_setkey(struct crypto_shash *tfm,
38                         const u8 *key, unsigned int keylen)
39 {
40         struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
41
42         if (keylen != GHASH_BLOCK_SIZE) {
43                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
44                 return -EINVAL;
45         }
46
47         memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
48         memset(ctx->icv, 0, GHASH_BLOCK_SIZE);
49
50         return 0;
51 }
52
53 static int ghash_update(struct shash_desc *desc,
54                          const u8 *src, unsigned int srclen)
55 {
56         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
57         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
58         unsigned int n;
59         u8 *buf = dctx->buffer;
60         int ret;
61
62         if (dctx->bytes) {
63                 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
64
65                 n = min(srclen, dctx->bytes);
66                 dctx->bytes -= n;
67                 srclen -= n;
68
69                 memcpy(pos, src, n);
70                 src += n;
71
72                 if (!dctx->bytes) {
73                         ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf,
74                                               GHASH_BLOCK_SIZE);
75                         BUG_ON(ret != GHASH_BLOCK_SIZE);
76                 }
77         }
78
79         n = srclen & ~(GHASH_BLOCK_SIZE - 1);
80         if (n) {
81                 ret = crypt_s390_kimd(KIMD_GHASH, ctx, src, n);
82                 BUG_ON(ret != n);
83                 src += n;
84                 srclen -= n;
85         }
86
87         if (srclen) {
88                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
89                 memcpy(buf, src, srclen);
90         }
91
92         return 0;
93 }
94
95 static void ghash_flush(struct ghash_ctx *ctx, struct ghash_desc_ctx *dctx)
96 {
97         u8 *buf = dctx->buffer;
98         int ret;
99
100         if (dctx->bytes) {
101                 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
102
103                 memset(pos, 0, dctx->bytes);
104
105                 ret = crypt_s390_kimd(KIMD_GHASH, ctx, buf, GHASH_BLOCK_SIZE);
106                 BUG_ON(ret != GHASH_BLOCK_SIZE);
107         }
108
109         dctx->bytes = 0;
110 }
111
112 static int ghash_final(struct shash_desc *desc, u8 *dst)
113 {
114         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
115         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
116
117         ghash_flush(ctx, dctx);
118         memcpy(dst, ctx->icv, GHASH_BLOCK_SIZE);
119
120         return 0;
121 }
122
123 static struct shash_alg ghash_alg = {
124         .digestsize     = GHASH_DIGEST_SIZE,
125         .init           = ghash_init,
126         .update         = ghash_update,
127         .final          = ghash_final,
128         .setkey         = ghash_setkey,
129         .descsize       = sizeof(struct ghash_desc_ctx),
130         .base           = {
131                 .cra_name               = "ghash",
132                 .cra_driver_name        = "ghash-s390",
133                 .cra_priority           = CRYPT_S390_PRIORITY,
134                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
135                 .cra_blocksize          = GHASH_BLOCK_SIZE,
136                 .cra_ctxsize            = sizeof(struct ghash_ctx),
137                 .cra_module             = THIS_MODULE,
138                 .cra_list               = LIST_HEAD_INIT(ghash_alg.base.cra_list),
139         },
140 };
141
142 static int __init ghash_mod_init(void)
143 {
144         if (!crypt_s390_func_available(KIMD_GHASH,
145                                        CRYPT_S390_MSA | CRYPT_S390_MSA4))
146                 return -EOPNOTSUPP;
147
148         return crypto_register_shash(&ghash_alg);
149 }
150
151 static void __exit ghash_mod_exit(void)
152 {
153         crypto_unregister_shash(&ghash_alg);
154 }
155
156 module_init(ghash_mod_init);
157 module_exit(ghash_mod_exit);
158
159 MODULE_ALIAS("ghash");
160
161 MODULE_LICENSE("GPL");
162 MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");