tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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
18struct ghash_ctx {
19 u8 key[GHASH_BLOCK_SIZE];
20};
21
22struct 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
29static 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
40static 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
55static 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 int ret;
62
63 if (dctx->bytes) {
64 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
65
66 n = min(srclen, dctx->bytes);
67 dctx->bytes -= n;
68 srclen -= n;
69
70 memcpy(pos, src, n);
71 src += n;
72
73 if (!dctx->bytes) {
74 ret = cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf,
75 GHASH_BLOCK_SIZE);
76 if (ret != GHASH_BLOCK_SIZE)
77 return -EIO;
78 }
79 }
80
81 n = srclen & ~(GHASH_BLOCK_SIZE - 1);
82 if (n) {
83 ret = cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
84 if (ret != n)
85 return -EIO;
86 src += n;
87 srclen -= n;
88 }
89
90 if (srclen) {
91 dctx->bytes = GHASH_BLOCK_SIZE - srclen;
92 memcpy(buf, src, srclen);
93 }
94
95 return 0;
96}
97
98static int ghash_flush(struct ghash_desc_ctx *dctx)
99{
100 u8 *buf = dctx->buffer;
101 int ret;
102
103 if (dctx->bytes) {
104 u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes);
105
106 memset(pos, 0, dctx->bytes);
107
108 ret = cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
109 if (ret != GHASH_BLOCK_SIZE)
110 return -EIO;
111
112 dctx->bytes = 0;
113 }
114
115 return 0;
116}
117
118static int ghash_final(struct shash_desc *desc, u8 *dst)
119{
120 struct ghash_desc_ctx *dctx = shash_desc_ctx(desc);
121 int ret;
122
123 ret = ghash_flush(dctx);
124 if (!ret)
125 memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
126 return ret;
127}
128
129static struct shash_alg ghash_alg = {
130 .digestsize = GHASH_DIGEST_SIZE,
131 .init = ghash_init,
132 .update = ghash_update,
133 .final = ghash_final,
134 .setkey = ghash_setkey,
135 .descsize = sizeof(struct ghash_desc_ctx),
136 .base = {
137 .cra_name = "ghash",
138 .cra_driver_name = "ghash-s390",
139 .cra_priority = 300,
140 .cra_flags = CRYPTO_ALG_TYPE_SHASH,
141 .cra_blocksize = GHASH_BLOCK_SIZE,
142 .cra_ctxsize = sizeof(struct ghash_ctx),
143 .cra_module = THIS_MODULE,
144 },
145};
146
147static int __init ghash_mod_init(void)
148{
149 if (!cpacf_query(CPACF_KIMD, CPACF_KIMD_GHASH))
150 return -EOPNOTSUPP;
151
152 return crypto_register_shash(&ghash_alg);
153}
154
155static void __exit ghash_mod_exit(void)
156{
157 crypto_unregister_shash(&ghash_alg);
158}
159
160module_cpu_feature_match(MSA, ghash_mod_init);
161module_exit(ghash_mod_exit);
162
163MODULE_ALIAS_CRYPTO("ghash");
164
165MODULE_LICENSE("GPL");
166MODULE_DESCRIPTION("GHASH Message Digest Algorithm, s390 implementation");