summaryrefslogtreecommitdiff
path: root/crypto/sha1_generic.c
blob: 9efef20454cba0281c9e08c9ec02da4eae0e3665 (plain) (blame)
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
/*
 * Cryptographic API.
 *
 * SHA1 Secure Hash Algorithm.
 *
 * Derived from cryptoapi implementation, adapted for in-place
 * scatterlist interface.
 *
 * Copyright (c) Alan Smithee.
 * Copyright (c) Andrew McDonald <andrew@mcdonald.org.uk>
 * Copyright (c) Jean-Francois Dive <jef@linuxbe.org>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 2 of the License, or (at your option)
 * any later version.
 *
 */
#include <crypto/internal/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/cryptohash.h>
#include <linux/types.h>
#include <crypto/sha.h>
#include <asm/byteorder.h>

struct sha1_ctx {
        u64 count;
        u32 state[5];
        u8 buffer[64];
};

static int sha1_init(struct shash_desc *desc)
{
	struct sha1_ctx *sctx = shash_desc_ctx(desc);

	static const struct sha1_ctx initstate = {
	  0,
	  { SHA1_H0, SHA1_H1, SHA1_H2, SHA1_H3, SHA1_H4 },
	  { 0, }
	};

	*sctx = initstate;

	return 0;
}

static int sha1_update(struct shash_desc *desc, const u8 *data,
			unsigned int len)
{
	struct sha1_ctx *sctx = shash_desc_ctx(desc);
	unsigned int partial, done;
	const u8 *src;

	partial = sctx->count & 0x3f;
	sctx->count += len;
	done = 0;
	src = data;

	if ((partial + len) > 63) {
		u32 temp[SHA_WORKSPACE_WORDS];

		if (partial) {
			done = -partial;
			memcpy(sctx->buffer + partial, data, done + 64);
			src = sctx->buffer;
		}

		do {
			sha_transform(sctx->state, src, temp);
			done += 64;
			src = data + done;
		} while (done + 63 < len);

		memset(temp, 0, sizeof(temp));
		partial = 0;
	}
	memcpy(sctx->buffer + partial, src, len - done);

	return 0;
}


/* Add padding and return the message digest. */
static int sha1_final(struct shash_desc *desc, u8 *out)
{
	struct sha1_ctx *sctx = shash_desc_ctx(desc);
	__be32 *dst = (__be32 *)out;
	u32 i, index, padlen;
	__be64 bits;
	static const u8 padding[64] = { 0x80, };

	bits = cpu_to_be64(sctx->count << 3);

	/* Pad out to 56 mod 64 */
	index = sctx->count & 0x3f;
	padlen = (index < 56) ? (56 - index) : ((64+56) - index);
	sha1_update(desc, padding, padlen);

	/* Append length */
	sha1_update(desc, (const u8 *)&bits, sizeof(bits));

	/* Store state in digest */
	for (i = 0; i < 5; i++)
		dst[i] = cpu_to_be32(sctx->state[i]);

	/* Wipe context */
	memset(sctx, 0, sizeof *sctx);

	return 0;
}

static struct shash_alg alg = {
	.digestsize	=	SHA1_DIGEST_SIZE,
	.init		=	sha1_init,
	.update		=	sha1_update,
	.final		=	sha1_final,
	.descsize	=	sizeof(struct sha1_ctx),
	.base		=	{
		.cra_name	=	"sha1",
		.cra_driver_name=	"sha1-generic",
		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
		.cra_blocksize	=	SHA1_BLOCK_SIZE,
		.cra_module	=	THIS_MODULE,
	}
};

static int __init sha1_generic_mod_init(void)
{
	return crypto_register_shash(&alg);
}

static void __exit sha1_generic_mod_fini(void)
{
	crypto_unregister_shash(&alg);
}

module_init(sha1_generic_mod_init);
module_exit(sha1_generic_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("SHA1 Secure Hash Algorithm");

MODULE_ALIAS("sha1");