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Linux kernel mirror (for testing)
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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Cryptographic API.
4 *
5 * s390 implementation of the GHASH algorithm for GCM (Galois/Counter Mode).
6 *
7 * Copyright IBM Corp. 2011
8 * Author(s): Gerald Schaefer <gerald.schaefer@de.ibm.com>
9 */
10
11#include <asm/cpacf.h>
12#include <crypto/ghash.h>
13#include <crypto/internal/hash.h>
14#include <linux/cpufeature.h>
15#include <linux/err.h>
16#include <linux/kernel.h>
17#include <linux/module.h>
18#include <linux/string.h>
19
20struct s390_ghash_ctx {
21 u8 key[GHASH_BLOCK_SIZE];
22};
23
24struct s390_ghash_desc_ctx {
25 u8 icv[GHASH_BLOCK_SIZE];
26 u8 key[GHASH_BLOCK_SIZE];
27};
28
29static int ghash_init(struct shash_desc *desc)
30{
31 struct s390_ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
32 struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
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 s390_ghash_ctx *ctx = crypto_shash_ctx(tfm);
44
45 if (keylen != GHASH_BLOCK_SIZE)
46 return -EINVAL;
47
48 memcpy(ctx->key, key, GHASH_BLOCK_SIZE);
49
50 return 0;
51}
52
53static int ghash_update(struct shash_desc *desc,
54 const u8 *src, unsigned int srclen)
55{
56 struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
57 unsigned int n;
58
59 n = srclen & ~(GHASH_BLOCK_SIZE - 1);
60 cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n);
61 return srclen - n;
62}
63
64static void ghash_flush(struct s390_ghash_desc_ctx *dctx, const u8 *src,
65 unsigned int len)
66{
67 if (len) {
68 u8 buf[GHASH_BLOCK_SIZE] = {};
69
70 memcpy(buf, src, len);
71 cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE);
72 memzero_explicit(buf, sizeof(buf));
73 }
74}
75
76static int ghash_finup(struct shash_desc *desc, const u8 *src,
77 unsigned int len, u8 *dst)
78{
79 struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
80
81 ghash_flush(dctx, src, len);
82 memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE);
83 return 0;
84}
85
86static int ghash_export(struct shash_desc *desc, void *out)
87{
88 struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
89
90 memcpy(out, dctx->icv, GHASH_DIGEST_SIZE);
91 return 0;
92}
93
94static int ghash_import(struct shash_desc *desc, const void *in)
95{
96 struct s390_ghash_ctx *ctx = crypto_shash_ctx(desc->tfm);
97 struct s390_ghash_desc_ctx *dctx = shash_desc_ctx(desc);
98
99 memcpy(dctx->icv, in, GHASH_DIGEST_SIZE);
100 memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE);
101 return 0;
102}
103
104static struct shash_alg ghash_alg = {
105 .digestsize = GHASH_DIGEST_SIZE,
106 .init = ghash_init,
107 .update = ghash_update,
108 .finup = ghash_finup,
109 .setkey = ghash_setkey,
110 .export = ghash_export,
111 .import = ghash_import,
112 .statesize = sizeof(struct ghash_desc_ctx),
113 .descsize = sizeof(struct s390_ghash_desc_ctx),
114 .base = {
115 .cra_name = "ghash",
116 .cra_driver_name = "ghash-s390",
117 .cra_priority = 300,
118 .cra_flags = CRYPTO_AHASH_ALG_BLOCK_ONLY,
119 .cra_blocksize = GHASH_BLOCK_SIZE,
120 .cra_ctxsize = sizeof(struct s390_ghash_ctx),
121 .cra_module = THIS_MODULE,
122 },
123};
124
125static int __init ghash_mod_init(void)
126{
127 if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH))
128 return -ENODEV;
129
130 return crypto_register_shash(&ghash_alg);
131}
132
133static void __exit ghash_mod_exit(void)
134{
135 crypto_unregister_shash(&ghash_alg);
136}
137
138module_cpu_feature_match(S390_CPU_FEATURE_MSA, ghash_mod_init);
139module_exit(ghash_mod_exit);
140
141MODULE_ALIAS_CRYPTO("ghash");
142
143MODULE_LICENSE("GPL");
144MODULE_DESCRIPTION("GHASH hash function, s390 implementation");