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 <asm/byteorder.h>
25
26#define F1(x, y, z)	(z ^ (x & (y ^ z)))
27#define F2(x, y, z)	F1(z, x, y)
28#define F3(x, y, z)	(x ^ y ^ z)
29#define F4(x, y, z)	(y ^ (x | ~z))
30
31#define MD5STEP(f, w, x, y, z, in, s) \
32	(w += f(x, y, z) + in, w = (w<<s | w>>(32-s)) + x)
33
34static void md5_transform(u32 *hash, u32 const *in)
35{
36	u32 a, b, c, d;
37
38	a = hash[0];
39	b = hash[1];
40	c = hash[2];
41	d = hash[3];
42
43	MD5STEP(F1, a, b, c, d, in[0] + 0xd76aa478, 7);
44	MD5STEP(F1, d, a, b, c, in[1] + 0xe8c7b756, 12);
45	MD5STEP(F1, c, d, a, b, in[2] + 0x242070db, 17);
46	MD5STEP(F1, b, c, d, a, in[3] + 0xc1bdceee, 22);
47	MD5STEP(F1, a, b, c, d, in[4] + 0xf57c0faf, 7);
48	MD5STEP(F1, d, a, b, c, in[5] + 0x4787c62a, 12);
49	MD5STEP(F1, c, d, a, b, in[6] + 0xa8304613, 17);
50	MD5STEP(F1, b, c, d, a, in[7] + 0xfd469501, 22);
51	MD5STEP(F1, a, b, c, d, in[8] + 0x698098d8, 7);
52	MD5STEP(F1, d, a, b, c, in[9] + 0x8b44f7af, 12);
53	MD5STEP(F1, c, d, a, b, in[10] + 0xffff5bb1, 17);
54	MD5STEP(F1, b, c, d, a, in[11] + 0x895cd7be, 22);
55	MD5STEP(F1, a, b, c, d, in[12] + 0x6b901122, 7);
56	MD5STEP(F1, d, a, b, c, in[13] + 0xfd987193, 12);
57	MD5STEP(F1, c, d, a, b, in[14] + 0xa679438e, 17);
58	MD5STEP(F1, b, c, d, a, in[15] + 0x49b40821, 22);
59
60	MD5STEP(F2, a, b, c, d, in[1] + 0xf61e2562, 5);
61	MD5STEP(F2, d, a, b, c, in[6] + 0xc040b340, 9);
62	MD5STEP(F2, c, d, a, b, in[11] + 0x265e5a51, 14);
63	MD5STEP(F2, b, c, d, a, in[0] + 0xe9b6c7aa, 20);
64	MD5STEP(F2, a, b, c, d, in[5] + 0xd62f105d, 5);
65	MD5STEP(F2, d, a, b, c, in[10] + 0x02441453, 9);
66	MD5STEP(F2, c, d, a, b, in[15] + 0xd8a1e681, 14);
67	MD5STEP(F2, b, c, d, a, in[4] + 0xe7d3fbc8, 20);
68	MD5STEP(F2, a, b, c, d, in[9] + 0x21e1cde6, 5);
69	MD5STEP(F2, d, a, b, c, in[14] + 0xc33707d6, 9);
70	MD5STEP(F2, c, d, a, b, in[3] + 0xf4d50d87, 14);
71	MD5STEP(F2, b, c, d, a, in[8] + 0x455a14ed, 20);
72	MD5STEP(F2, a, b, c, d, in[13] + 0xa9e3e905, 5);
73	MD5STEP(F2, d, a, b, c, in[2] + 0xfcefa3f8, 9);
74	MD5STEP(F2, c, d, a, b, in[7] + 0x676f02d9, 14);
75	MD5STEP(F2, b, c, d, a, in[12] + 0x8d2a4c8a, 20);
76
77	MD5STEP(F3, a, b, c, d, in[5] + 0xfffa3942, 4);
78	MD5STEP(F3, d, a, b, c, in[8] + 0x8771f681, 11);
79	MD5STEP(F3, c, d, a, b, in[11] + 0x6d9d6122, 16);
80	MD5STEP(F3, b, c, d, a, in[14] + 0xfde5380c, 23);
81	MD5STEP(F3, a, b, c, d, in[1] + 0xa4beea44, 4);
82	MD5STEP(F3, d, a, b, c, in[4] + 0x4bdecfa9, 11);
83	MD5STEP(F3, c, d, a, b, in[7] + 0xf6bb4b60, 16);
84	MD5STEP(F3, b, c, d, a, in[10] + 0xbebfbc70, 23);
85	MD5STEP(F3, a, b, c, d, in[13] + 0x289b7ec6, 4);
86	MD5STEP(F3, d, a, b, c, in[0] + 0xeaa127fa, 11);
87	MD5STEP(F3, c, d, a, b, in[3] + 0xd4ef3085, 16);
88	MD5STEP(F3, b, c, d, a, in[6] + 0x04881d05, 23);
89	MD5STEP(F3, a, b, c, d, in[9] + 0xd9d4d039, 4);
90	MD5STEP(F3, d, a, b, c, in[12] + 0xe6db99e5, 11);
91	MD5STEP(F3, c, d, a, b, in[15] + 0x1fa27cf8, 16);
92	MD5STEP(F3, b, c, d, a, in[2] + 0xc4ac5665, 23);
93
94	MD5STEP(F4, a, b, c, d, in[0] + 0xf4292244, 6);
95	MD5STEP(F4, d, a, b, c, in[7] + 0x432aff97, 10);
96	MD5STEP(F4, c, d, a, b, in[14] + 0xab9423a7, 15);
97	MD5STEP(F4, b, c, d, a, in[5] + 0xfc93a039, 21);
98	MD5STEP(F4, a, b, c, d, in[12] + 0x655b59c3, 6);
99	MD5STEP(F4, d, a, b, c, in[3] + 0x8f0ccc92, 10);
100	MD5STEP(F4, c, d, a, b, in[10] + 0xffeff47d, 15);
101	MD5STEP(F4, b, c, d, a, in[1] + 0x85845dd1, 21);
102	MD5STEP(F4, a, b, c, d, in[8] + 0x6fa87e4f, 6);
103	MD5STEP(F4, d, a, b, c, in[15] + 0xfe2ce6e0, 10);
104	MD5STEP(F4, c, d, a, b, in[6] + 0xa3014314, 15);
105	MD5STEP(F4, b, c, d, a, in[13] + 0x4e0811a1, 21);
106	MD5STEP(F4, a, b, c, d, in[4] + 0xf7537e82, 6);
107	MD5STEP(F4, d, a, b, c, in[11] + 0xbd3af235, 10);
108	MD5STEP(F4, c, d, a, b, in[2] + 0x2ad7d2bb, 15);
109	MD5STEP(F4, b, c, d, a, in[9] + 0xeb86d391, 21);
110
111	hash[0] += a;
112	hash[1] += b;
113	hash[2] += c;
114	hash[3] += d;
115}
116
117static inline void le32_to_cpu_array(u32 *buf, unsigned int words)
118{
119	while (words--) {
120		__le32_to_cpus(buf);
121		buf++;
122	}
123}
124
125static inline void cpu_to_le32_array(u32 *buf, unsigned int words)
126{
127	while (words--) {
128		__cpu_to_le32s(buf);
129		buf++;
130	}
131}
132
133static inline void md5_transform_helper(struct md5_state *ctx)
134{
135	le32_to_cpu_array(ctx->block, sizeof(ctx->block) / sizeof(u32));
136	md5_transform(ctx->hash, ctx->block);
137}
138
139static int md5_init(struct shash_desc *desc)
140{
141	struct md5_state *mctx = shash_desc_ctx(desc);
142
143	mctx->hash[0] = 0x67452301;
144	mctx->hash[1] = 0xefcdab89;
145	mctx->hash[2] = 0x98badcfe;
146	mctx->hash[3] = 0x10325476;
147	mctx->byte_count = 0;
148
149	return 0;
150}
151
152static int md5_update(struct shash_desc *desc, const u8 *data, unsigned int len)
153{
154	struct md5_state *mctx = shash_desc_ctx(desc);
155	const u32 avail = sizeof(mctx->block) - (mctx->byte_count & 0x3f);
156
157	mctx->byte_count += len;
158
159	if (avail > len) {
160		memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
161		       data, len);
162		return 0;
163	}
164
165	memcpy((char *)mctx->block + (sizeof(mctx->block) - avail),
166	       data, avail);
167
168	md5_transform_helper(mctx);
169	data += avail;
170	len -= avail;
171
172	while (len >= sizeof(mctx->block)) {
173		memcpy(mctx->block, data, sizeof(mctx->block));
174		md5_transform_helper(mctx);
175		data += sizeof(mctx->block);
176		len -= sizeof(mctx->block);
177	}
178
179	memcpy(mctx->block, data, len);
180
181	return 0;
182}
183
184static int md5_final(struct shash_desc *desc, u8 *out)
185{
186	struct md5_state *mctx = shash_desc_ctx(desc);
187	const unsigned int offset = mctx->byte_count & 0x3f;
188	char *p = (char *)mctx->block + offset;
189	int padding = 56 - (offset + 1);
190
191	*p++ = 0x80;
192	if (padding < 0) {
193		memset(p, 0x00, padding + sizeof (u64));
194		md5_transform_helper(mctx);
195		p = (char *)mctx->block;
196		padding = 56;
197	}
198
199	memset(p, 0, padding);
200	mctx->block[14] = mctx->byte_count << 3;
201	mctx->block[15] = mctx->byte_count >> 29;
202	le32_to_cpu_array(mctx->block, (sizeof(mctx->block) -
203	                  sizeof(u64)) / sizeof(u32));
204	md5_transform(mctx->hash, mctx->block);
205	cpu_to_le32_array(mctx->hash, sizeof(mctx->hash) / sizeof(u32));
206	memcpy(out, mctx->hash, sizeof(mctx->hash));
207	memset(mctx, 0, sizeof(*mctx));
208
209	return 0;
210}
211
212static int md5_export(struct shash_desc *desc, void *out)
213{
214	struct md5_state *ctx = shash_desc_ctx(desc);
215
216	memcpy(out, ctx, sizeof(*ctx));
217	return 0;
218}
219
220static int md5_import(struct shash_desc *desc, const void *in)
221{
222	struct md5_state *ctx = shash_desc_ctx(desc);
223
224	memcpy(ctx, in, sizeof(*ctx));
225	return 0;
226}
227
228static struct shash_alg alg = {
229	.digestsize	=	MD5_DIGEST_SIZE,
230	.init		=	md5_init,
231	.update		=	md5_update,
232	.final		=	md5_final,
233	.export		=	md5_export,
234	.import		=	md5_import,
235	.descsize	=	sizeof(struct md5_state),
236	.statesize	=	sizeof(struct md5_state),
237	.base		=	{
238		.cra_name	=	"md5",
239		.cra_flags	=	CRYPTO_ALG_TYPE_SHASH,
240		.cra_blocksize	=	MD5_HMAC_BLOCK_SIZE,
241		.cra_module	=	THIS_MODULE,
242	}
243};
244
245static int __init md5_mod_init(void)
246{
247	return crypto_register_shash(&alg);
248}
249
250static void __exit md5_mod_fini(void)
251{
252	crypto_unregister_shash(&alg);
253}
254
255module_init(md5_mod_init);
256module_exit(md5_mod_fini);
257
258MODULE_LICENSE("GPL");
259MODULE_DESCRIPTION("MD5 Message Digest Algorithm");
260