summaryrefslogtreecommitdiffstats
path: root/arch/arm64/crypto/ghash-ce-glue.c
blob: 833ec1e3f3e9b7491cc26da24fc0ba386b73de81 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
/*
 * Accelerated GHASH implementation with ARMv8 PMULL instructions.
 *
 * Copyright (C) 2014 Linaro Ltd. <ard.biesheuvel@linaro.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 as published
 * by the Free Software Foundation.
 */

#include <asm/neon.h>
#include <asm/unaligned.h>
#include <crypto/internal/hash.h>
#include <linux/cpufeature.h>
#include <linux/crypto.h>
#include <linux/module.h>

MODULE_DESCRIPTION("GHASH secure hash using ARMv8 Crypto Extensions");
MODULE_AUTHOR("Ard Biesheuvel <ard.biesheuvel@linaro.org>");
MODULE_LICENSE("GPL v2");

#define GHASH_BLOCK_SIZE	16
#define GHASH_DIGEST_SIZE	16

struct ghash_key {
	u64 a;
	u64 b;
};

struct ghash_desc_ctx {
	u64 digest[GHASH_DIGEST_SIZE/sizeof(u64)];
	u8 buf[GHASH_BLOCK_SIZE];
	u32 count;
};

asmlinkage void pmull_ghash_update(int blocks, u64 dg[], const char *src,
				   struct ghash_key const *k, const char *head);

static int ghash_init(struct shash_desc *desc)
{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);

	*ctx = (struct ghash_desc_ctx){};
	return 0;
}

static int ghash_update(struct shash_desc *desc, const u8 *src,
			unsigned int len)
{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

	ctx->count += len;

	if ((partial + len) >= GHASH_BLOCK_SIZE) {
		struct ghash_key *key = crypto_shash_ctx(desc->tfm);
		int blocks;

		if (partial) {
			int p = GHASH_BLOCK_SIZE - partial;

			memcpy(ctx->buf + partial, src, p);
			src += p;
			len -= p;
		}

		blocks = len / GHASH_BLOCK_SIZE;
		len %= GHASH_BLOCK_SIZE;

		kernel_neon_begin_partial(8);
		pmull_ghash_update(blocks, ctx->digest, src, key,
				   partial ? ctx->buf : NULL);
		kernel_neon_end();
		src += blocks * GHASH_BLOCK_SIZE;
		partial = 0;
	}
	if (len)
		memcpy(ctx->buf + partial, src, len);
	return 0;
}

static int ghash_final(struct shash_desc *desc, u8 *dst)
{
	struct ghash_desc_ctx *ctx = shash_desc_ctx(desc);
	unsigned int partial = ctx->count % GHASH_BLOCK_SIZE;

	if (partial) {
		struct ghash_key *key = crypto_shash_ctx(desc->tfm);

		memset(ctx->buf + partial, 0, GHASH_BLOCK_SIZE - partial);

		kernel_neon_begin_partial(8);
		pmull_ghash_update(1, ctx->digest, ctx->buf, key, NULL);
		kernel_neon_end();
	}
	put_unaligned_be64(ctx->digest[1], dst);
	put_unaligned_be64(ctx->digest[0], dst + 8);

	*ctx = (struct ghash_desc_ctx){};
	return 0;
}

static int ghash_setkey(struct crypto_shash *tfm,
			const u8 *inkey, unsigned int keylen)
{
	struct ghash_key *key = crypto_shash_ctx(tfm);
	u64 a, b;

	if (keylen != GHASH_BLOCK_SIZE) {
		crypto_shash_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN);
		return -EINVAL;
	}

	/* perform multiplication by 'x' in GF(2^128) */
	b = get_unaligned_be64(inkey);
	a = get_unaligned_be64(inkey + 8);

	key->a = (a << 1) | (b >> 63);
	key->b = (b << 1) | (a >> 63);

	if (b >> 63)
		key->b ^= 0xc200000000000000UL;

	return 0;
}

static struct shash_alg ghash_alg = {
	.digestsize	= GHASH_DIGEST_SIZE,
	.init		= ghash_init,
	.update		= ghash_update,
	.final		= ghash_final,
	.setkey		= ghash_setkey,
	.descsize	= sizeof(struct ghash_desc_ctx),
	.base		= {
		.cra_name		= "ghash",
		.cra_driver_name	= "ghash-ce",
		.cra_priority		= 200,
		.cra_flags		= CRYPTO_ALG_TYPE_SHASH,
		.cra_blocksize		= GHASH_BLOCK_SIZE,
		.cra_ctxsize		= sizeof(struct ghash_key),
		.cra_module		= THIS_MODULE,
	},
};

static int __init ghash_ce_mod_init(void)
{
	return crypto_register_shash(&ghash_alg);
}

static void __exit ghash_ce_mod_exit(void)
{
	crypto_unregister_shash(&ghash_alg);
}

module_cpu_feature_match(PMULL, ghash_ce_mod_init);
module_exit(ghash_ce_mod_exit);
OpenPOWER on IntegriCloud