aboutsummaryrefslogtreecommitdiffstats
path: root/crypto/md5.c
blob: 36f5e5b103f302dbeda611466fb97ab94b87511f (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
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
/* 
 * Cryptographic API.
 *
 * MD5 Message Digest Algorithm (RFC1321).
 *
 * Derived from cryptoapi implementation, originally based on the
 * public domain implementation written by Colin Plumb in 1993.
 *
 * Copyright (c) Cryptoapi developers.
 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
 * 
 * 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 <crypto/md5.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
#include <linux/types.h>
#include <linux/cryptohash.h>
#include <asm/byteorder.h>

/* XXX: this stuff can be optimized */
static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
{
	while (words--) {
		__le32_to_cpus(buf);
		buf++;
	}
}

static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
{
	while (words--) {
		__cpu_to_le32s(buf);
		buf++;
	}
}

static inline void md5_transform_helper(struct md5_state *ctx)
{
	le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
	md5_transform(ctx->hash, ctx->block);
}

static int md5_init(struct shash_desc *desc)
{
	struct md5_state *mctx = shash_desc_ctx(desc);

	mctx->hash[0] = 0x67452301;
	mctx->hash[1] = 0xefcdab89;
	mctx->hash[2] = 0x98badcfe;
	mctx->hash[3] = 0x10325476;
	mctx->byte_count = 0;

	return 0;
}

static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
{
	struct md5_state *mctx = shash_desc_ctx(desc);
	const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);

	mctx->byte_count += len;

	if (avail > len) {
		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
		       data, len);
		return 0;
	}

	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
	       data, avail);

	md5_transform_helper(mctx);
	data += avail;
	len -= avail;

	while (len >= sizeof(mctx->block)) {
		memcpy(mctx->block, data, sizeof(mctx->block));
		md5_transform_helper(mctx);
		data += sizeof(mctx->block);
		len -= sizeof(mctx->block);
	}

	memcpy(mctx->block, data, len);

	return 0;
}

static int md5_final(struct shash_desc *desc, u8 *out)
{
	struct md5_state *mctx = shash_desc_ctx(desc);
	const unsigned int offset = mctx->byte_count & 0x3f;
	char *p = (char *)mctx->block + offset;
	int padding = 56 - (offset + 1);

	*p++ = 0x80;
	if (padding < 0) {
		memset(p, 0x00, padding + sizeof (u64));
		md5_transform_helper(mctx);
		p = (char *)mctx->block;
		padding = 56;
	}

	memset(p, 0, padding);
	mctx->block[14] = mctx->byte_count << 3;
	mctx->block[15] = mctx->byte_count >> 29;
	le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
	                  sizeof(u64)) / sizeof(u32));
	md5_transform(mctx->hash, mctx->block);
	cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
	memcpy(out, mctx->hash, sizeof(mctx->hash));
	memset(mctx, 0, sizeof(*mctx));

	return 0;
}

static int md5_export(struct shash_desc *desc, void *out)
{
	struct md5_state *ctx = shash_desc_ctx(desc);

	memcpy(out, ctx, sizeof(*ctx));
	return 0;
}

static int md5_import(struct shash_desc *desc, const void *in)
{
	struct md5_state *ctx = shash_desc_ctx(desc);

	memcpy(ctx, in, sizeof(*ctx));
	return 0;
}

static struct shash_alg alg = {
	.digestsize	=	MD5_DIGEST_SIZE,
	.init		=	md5_init,
	.update		=	md5_update,
	.final		=	md5_final,
	.export		=	md5_export,
	.import		=	md5_import,
	.descsize	=	sizeof(struct md5_state),
	.statesize	=	sizeof(struct md5_state),
	.base		=	{
		.cra_name	=	"md5",
		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
		.cra_blocksize	=	MD5_HMAC_BLOCK_SIZE,
		.cra_module	=	THIS_MODULE,
	}
};

static int __init md5_mod_init(void)
{
	return crypto_register_shash(&alg);
}

static void __exit md5_mod_fini(void)
{
	crypto_unregister_shash(&alg);
}

module_init(md5_mod_init);
module_exit(md5_mod_fini);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
MODULE_ALIAS_CRYPTO("md5");