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 <crypto/internal/hash.h> |
12 | #include <linux/module.h> |
13 | #include <linux/cpufeature.h> |
14 | #include <asm/cpacf.h> |
15 | |
16 | #define GHASH_BLOCK_SIZE 16 |
17 | #define GHASH_DIGEST_SIZE 16 |
18 | |
19 | struct ghash_ctx { |
20 | u8 key[GHASH_BLOCK_SIZE]; |
21 | }; |
22 | |
23 | struct ghash_desc_ctx { |
24 | u8 icv[GHASH_BLOCK_SIZE]; |
25 | u8 key[GHASH_BLOCK_SIZE]; |
26 | u8 buffer[GHASH_BLOCK_SIZE]; |
27 | u32 bytes; |
28 | }; |
29 | |
30 | static int ghash_init(struct shash_desc *desc) |
31 | { |
32 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); |
33 | struct ghash_ctx *ctx = crypto_shash_ctx(tfm: desc->tfm); |
34 | |
35 | memset(dctx, 0, sizeof(*dctx)); |
36 | memcpy(dctx->key, ctx->key, GHASH_BLOCK_SIZE); |
37 | |
38 | return 0; |
39 | } |
40 | |
41 | static int ghash_setkey(struct crypto_shash *tfm, |
42 | const u8 *key, unsigned int keylen) |
43 | { |
44 | struct ghash_ctx *ctx = crypto_shash_ctx(tfm); |
45 | |
46 | if (keylen != GHASH_BLOCK_SIZE) |
47 | return -EINVAL; |
48 | |
49 | memcpy(ctx->key, key, GHASH_BLOCK_SIZE); |
50 | |
51 | return 0; |
52 | } |
53 | |
54 | static int ghash_update(struct shash_desc *desc, |
55 | const u8 *src, unsigned int srclen) |
56 | { |
57 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); |
58 | unsigned int n; |
59 | u8 *buf = dctx->buffer; |
60 | |
61 | if (dctx->bytes) { |
62 | u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes); |
63 | |
64 | n = min(srclen, dctx->bytes); |
65 | dctx->bytes -= n; |
66 | srclen -= n; |
67 | |
68 | memcpy(pos, src, n); |
69 | src += n; |
70 | |
71 | if (!dctx->bytes) { |
72 | cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, |
73 | GHASH_BLOCK_SIZE); |
74 | } |
75 | } |
76 | |
77 | n = srclen & ~(GHASH_BLOCK_SIZE - 1); |
78 | if (n) { |
79 | cpacf_kimd(CPACF_KIMD_GHASH, dctx, src, n); |
80 | src += n; |
81 | srclen -= n; |
82 | } |
83 | |
84 | if (srclen) { |
85 | dctx->bytes = GHASH_BLOCK_SIZE - srclen; |
86 | memcpy(buf, src, srclen); |
87 | } |
88 | |
89 | return 0; |
90 | } |
91 | |
92 | static int ghash_flush(struct ghash_desc_ctx *dctx) |
93 | { |
94 | u8 *buf = dctx->buffer; |
95 | |
96 | if (dctx->bytes) { |
97 | u8 *pos = buf + (GHASH_BLOCK_SIZE - dctx->bytes); |
98 | |
99 | memset(pos, 0, dctx->bytes); |
100 | cpacf_kimd(CPACF_KIMD_GHASH, dctx, buf, GHASH_BLOCK_SIZE); |
101 | dctx->bytes = 0; |
102 | } |
103 | |
104 | return 0; |
105 | } |
106 | |
107 | static int ghash_final(struct shash_desc *desc, u8 *dst) |
108 | { |
109 | struct ghash_desc_ctx *dctx = shash_desc_ctx(desc); |
110 | int ret; |
111 | |
112 | ret = ghash_flush(dctx); |
113 | if (!ret) |
114 | memcpy(dst, dctx->icv, GHASH_BLOCK_SIZE); |
115 | return ret; |
116 | } |
117 | |
118 | static struct shash_alg ghash_alg = { |
119 | .digestsize = GHASH_DIGEST_SIZE, |
120 | .init = ghash_init, |
121 | .update = ghash_update, |
122 | .final = ghash_final, |
123 | .setkey = ghash_setkey, |
124 | .descsize = sizeof(struct ghash_desc_ctx), |
125 | .base = { |
126 | .cra_name = "ghash" , |
127 | .cra_driver_name = "ghash-s390" , |
128 | .cra_priority = 300, |
129 | .cra_blocksize = GHASH_BLOCK_SIZE, |
130 | .cra_ctxsize = sizeof(struct ghash_ctx), |
131 | .cra_module = THIS_MODULE, |
132 | }, |
133 | }; |
134 | |
135 | static int __init ghash_mod_init(void) |
136 | { |
137 | if (!cpacf_query_func(CPACF_KIMD, CPACF_KIMD_GHASH)) |
138 | return -ENODEV; |
139 | |
140 | return crypto_register_shash(alg: &ghash_alg); |
141 | } |
142 | |
143 | static void __exit ghash_mod_exit(void) |
144 | { |
145 | crypto_unregister_shash(alg: &ghash_alg); |
146 | } |
147 | |
148 | module_cpu_feature_match(S390_CPU_FEATURE_MSA, ghash_mod_init); |
149 | module_exit(ghash_mod_exit); |
150 | |
151 | MODULE_ALIAS_CRYPTO("ghash" ); |
152 | |
153 | MODULE_LICENSE("GPL" ); |
154 | MODULE_DESCRIPTION("GHASH hash function, s390 implementation" ); |
155 | |