1/*
2 * Cryptographic API.
3 *
4 * MD5 Message Digest Algorithm (RFC1321).
5 *
6 * Derived from cryptoapi implementation, originally based on the
7 * public domain implementation written by Colin Plumb in 1993.
8 *
9 * Copyright (c) Cryptoapi developers.
10 * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
11 *
12 * This program is free software; you can redistribute it and/or modify it
13 * under the terms of the GNU General Public License as published by the Free
14 * Software Foundation; either version 2 of the License, or (at your option)
15 * any later version.
16 *
17 */
18#include <crypto/internal/hash.h>
19#include <crypto/md5.h>
20#include <linux/init.h>
21#include <linux/module.h>
22#include <linux/string.h>
23#include <linux/types.h>
24#include <linux/cryptohash.h>
25#include <asm/byteorder.h>
26
27/* XXX: this stuff can be optimized */
28static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
29{
30	while (words--) {
31		__le32_to_cpus(buf);
32		buf++;
33	}
34}
35
36static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
37{
38	while (words--) {
39		__cpu_to_le32s(buf);
40		buf++;
41	}
42}
43
44static inline void md5_transform_helper(struct md5_state *ctx)
45{
46	le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
47	md5_transform(ctx->hash, ctx->block);
48}
49
50static int md5_init(struct shash_desc *desc)
51{
52	struct md5_state *mctx = shash_desc_ctx(desc);
53
54	mctx->hash[0] = MD5_H0;
55	mctx->hash[1] = MD5_H1;
56	mctx->hash[2] = MD5_H2;
57	mctx->hash[3] = MD5_H3;
58	mctx->byte_count = 0;
59
60	return 0;
61}
62
63static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
64{
65	struct md5_state *mctx = shash_desc_ctx(desc);
66	const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
67
68	mctx->byte_count += len;
69
70	if (avail > len) {
71		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
72		       data, len);
73		return 0;
74	}
75
76	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
77	       data, avail);
78
79	md5_transform_helper(mctx);
80	data += avail;
81	len -= avail;
82
83	while (len >= sizeof(mctx->block)) {
84		memcpy(mctx->block, data, sizeof(mctx->block));
85		md5_transform_helper(mctx);
86		data += sizeof(mctx->block);
87		len -= sizeof(mctx->block);
88	}
89
90	memcpy(mctx->block, data, len);
91
92	return 0;
93}
94
95static int md5_final(struct shash_desc *desc, u8 *out)
96{
97	struct md5_state *mctx = shash_desc_ctx(desc);
98	const unsigned int offset = mctx->byte_count & 0x3f;
99	char *p = (char *)mctx->block + offset;
100	int padding = 56 - (offset + 1);
101
102	*p++ = 0x80;
103	if (padding < 0) {
104		memset(p, 0x00, padding + sizeof (u64));
105		md5_transform_helper(mctx);
106		p = (char *)mctx->block;
107		padding = 56;
108	}
109
110	memset(p, 0, padding);
111	mctx->block[14] = mctx->byte_count << 3;
112	mctx->block[15] = mctx->byte_count >> 29;
113	le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
114	                  sizeof(u64)) / sizeof(u32));
115	md5_transform(mctx->hash, mctx->block);
116	cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
117	memcpy(out, mctx->hash, sizeof(mctx->hash));
118	memset(mctx, 0, sizeof(*mctx));
119
120	return 0;
121}
122
123static int md5_export(struct shash_desc *desc, void *out)
124{
125	struct md5_state *ctx = shash_desc_ctx(desc);
126
127	memcpy(out, ctx, sizeof(*ctx));
128	return 0;
129}
130
131static int md5_import(struct shash_desc *desc, const void *in)
132{
133	struct md5_state *ctx = shash_desc_ctx(desc);
134
135	memcpy(ctx, in, sizeof(*ctx));
136	return 0;
137}
138
139static struct shash_alg alg = {
140	.digestsize	=	MD5_DIGEST_SIZE,
141	.init		=	md5_init,
142	.update		=	md5_update,
143	.final		=	md5_final,
144	.export		=	md5_export,
145	.import		=	md5_import,
146	.descsize	=	sizeof(struct md5_state),
147	.statesize	=	sizeof(struct md5_state),
148	.base		=	{
149		.cra_name	=	"md5",
150		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
151		.cra_blocksize	=	MD5_HMAC_BLOCK_SIZE,
152		.cra_module	=	THIS_MODULE,
153	}
154};
155
156static int __init md5_mod_init(void)
157{
158	return crypto_register_shash(&alg);
159}
160
161static void __exit md5_mod_fini(void)
162{
163	crypto_unregister_shash(&alg);
164}
165
166module_init(md5_mod_init);
167module_exit(md5_mod_fini);
168
169MODULE_LICENSE("GPL");
170MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
171MODULE_ALIAS_CRYPTO("md5");
172