GNU Linux-libre 4.9.288-gnu1
[releases.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 #include <linux/cpufeature.h>
13 #include <asm/cpacf.h>
14
15 #define GHASH_BLOCK_SIZE        16
16 #define GHASH_DIGEST_SIZE       16
17
18 struct ghash_ctx {
19         u8 key[GHASH_BLOCK_SIZE];
20 };
21
22 struct ghash_desc_ctx {
23         u8 icv[GHASH_BLOCK_SIZE];
24         u8 key[GHASH_BLOCK_SIZE];
25         u8 buffer[GHASH_BLOCK_SIZE];
26         u32 bytes;
27 };
28
29 static int ghash_init(struct shash_desc *desc)
30 {
31         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
32         struct ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
33
34         memset(dctx, 0, sizeof(*dctx));
35         memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
36
37         return 0;
38 }
39
40 static int ghash_setkey(struct crypto_shash *tfm,
41                         const u8 *key, unsigned int keylen)
42 {
43         struct ghash_ctx *ctx = crypto_shash_ctx(tfm);
44
45         if (keylen != GHASH_BLOCK_SIZE) {
46                 crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
47                 return -EINVAL;
48         }
49
50         memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
51
52         return 0;
53 }
54
55 static int ghash_update(struct shash_desc *desc,
56                          const u8 *src, unsigned int srclen)
57 {
58         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
59         unsigned int n;
60         u8 *buf = dctx->buffer;
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                         cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
74                                    GHASH_BLOCK_SIZE);
75                 }
76         }
77
78         n = srclen & ~(GHASH_BLOCK_SIZE - 1);
79         if (n) {
80                 cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
81                 src += n;
82                 srclen -= n;
83         }
84
85         if (srclen) {
86                 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
87                 memcpy(buf, src, srclen);
88         }
89
90         return 0;
91 }
92
93 static int ghash_flush(struct ghash_desc_ctx *dctx)
94 {
95         u8 *buf = dctx->buffer;
96
97         if (dctx->bytes) {
98                 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
99
100                 memset(pos, 0, dctx->bytes);
101                 cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
102                 dctx->bytes = 0;
103         }
104
105         return 0;
106 }
107
108 static int ghash_final(struct shash_desc *desc, u8 *dst)
109 {
110         struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
111         int ret;
112
113         ret = ghash_flush(dctx);
114         if (!ret)
115                 memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
116         return ret;
117 }
118
119 static struct shash_alg ghash_alg = {
120         .digestsize     = GHASH_DIGEST_SIZE,
121         .init           = ghash_init,
122         .update         = ghash_update,
123         .final          = ghash_final,
124         .setkey         = ghash_setkey,
125         .descsize       = sizeof(struct ghash_desc_ctx),
126         .base           = {
127                 .cra_name               = "ghash",
128                 .cra_driver_name        = "ghash-s390",
129                 .cra_priority           = 300,
130                 .cra_flags              = CRYPTO_ALG_TYPE_SHASH,
131                 .cra_blocksize          = GHASH_BLOCK_SIZE,
132                 .cra_ctxsize            = sizeof(struct ghash_ctx),
133                 .cra_module             = THIS_MODULE,
134         },
135 };
136
137 static int __init ghash_mod_init(void)
138 {
139         if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
140                 return -EOPNOTSUPP;
141
142         return crypto_register_shash(&ghash_alg);
143 }
144
145 static void __exit ghash_mod_exit(void)
146 {
147         crypto_unregister_shash(&ghash_alg);
148 }
149
150 module_cpu_feature_match(MSA, ghash_mod_init);
151 module_exit(ghash_mod_exit);
152
153 MODULE_ALIAS_CRYPTO("ghash");
154
155 MODULE_LICENSE("GPL");
156 MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");