1 /*
2 * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 *
19 * You can also choose to distribute this program under the terms of
20 * the Unmodified Binary Distribution Licence (as given in the file
21 * COPYING.UBDL), provided that you have satisfied its requirements.
22 */
23
24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
25
26 /** @file
27 *
28 * MD5 algorithm
29 *
30 */
31
32 #include <stdint.h>
33 #include <string.h>
34 #include <byteswap.h>
35 #include <assert.h>
36 #include <ipxe/rotate.h>
37 #include <ipxe/crypto.h>
38 #include <ipxe/asn1.h>
39 #include <ipxe/md5.h>
40
41 /** MD5 variables */
42 struct md5_variables {
43 /* This layout matches that of struct md5_digest_data,
44 * allowing for efficient endianness-conversion,
45 */
46 uint32_t a;
47 uint32_t b;
48 uint32_t c;
49 uint32_t d;
50 uint32_t w[16];
51 } __attribute__ (( packed ));
52
53 /** MD5 constants */
54 static const uint32_t k[64] = {
55 0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee, 0xf57c0faf, 0x4787c62a,
56 0xa8304613, 0xfd469501, 0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
57 0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821, 0xf61e2562, 0xc040b340,
58 0x265e5a51, 0xe9b6c7aa, 0xd62f105d, 0x02441453, 0xd8a1e681, 0xe7d3fbc8,
59 0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed, 0xa9e3e905, 0xfcefa3f8,
60 0x676f02d9, 0x8d2a4c8a, 0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
61 0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70, 0x289b7ec6, 0xeaa127fa,
62 0xd4ef3085, 0x04881d05, 0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
63 0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039, 0x655b59c3, 0x8f0ccc92,
64 0xffeff47d, 0x85845dd1, 0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
65 0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
66 };
67
68 /** MD5 shift amounts */
69 static const uint8_t r[4][4] = {
70 { 7, 12, 17, 22 },
71 { 5, 9, 14, 20 },
72 { 4, 11, 16, 23 },
73 { 6, 10, 15, 21 },
74 };
75
76 /**
77 * f(b,c,d) for steps 0 to 15
78 *
79 * @v v MD5 variables
80 * @ret f f(b,c,d)
81 */
md5_f_0_15(struct md5_variables * v)82 static uint32_t md5_f_0_15 ( struct md5_variables *v ) {
83 return ( v->d ^ ( v->b & ( v->c ^ v->d ) ) );
84 }
85
86 /**
87 * f(b,c,d) for steps 16 to 31
88 *
89 * @v v MD5 variables
90 * @ret f f(b,c,d)
91 */
md5_f_16_31(struct md5_variables * v)92 static uint32_t md5_f_16_31 ( struct md5_variables *v ) {
93 return ( v->c ^ ( v->d & ( v->b ^ v->c ) ) );
94 }
95
96 /**
97 * f(b,c,d) for steps 32 to 47
98 *
99 * @v v MD5 variables
100 * @ret f f(b,c,d)
101 */
md5_f_32_47(struct md5_variables * v)102 static uint32_t md5_f_32_47 ( struct md5_variables *v ) {
103 return ( v->b ^ v->c ^ v->d );
104 }
105
106 /**
107 * f(b,c,d) for steps 48 to 63
108 *
109 * @v v MD5 variables
110 * @ret f f(b,c,d)
111 */
md5_f_48_63(struct md5_variables * v)112 static uint32_t md5_f_48_63 ( struct md5_variables *v ) {
113 return ( v->c ^ ( v->b | (~v->d) ) );
114 }
115
116 /** An MD5 step function */
117 struct md5_step {
118 /**
119 * Calculate f(b,c,d)
120 *
121 * @v v MD5 variables
122 * @ret f f(b,c,d)
123 */
124 uint32_t ( * f ) ( struct md5_variables *v );
125 /** Coefficient of i in g=ni+m */
126 uint8_t coefficient;
127 /** Constant term in g=ni+m */
128 uint8_t constant;
129 };
130
131 /** MD5 steps */
132 static struct md5_step md5_steps[4] = {
133 /** 0 to 15 */
134 { .f = md5_f_0_15, .coefficient = 1, .constant = 0 },
135 /** 16 to 31 */
136 { .f = md5_f_16_31, .coefficient = 5, .constant = 1 },
137 /** 32 to 47 */
138 { .f = md5_f_32_47, .coefficient = 3, .constant = 5 },
139 /** 48 to 63 */
140 { .f = md5_f_48_63, .coefficient = 7, .constant = 0 },
141 };
142
143 /**
144 * Initialise MD5 algorithm
145 *
146 * @v ctx MD5 context
147 */
md5_init(void * ctx)148 static void md5_init ( void *ctx ) {
149 struct md5_context *context = ctx;
150
151 context->ddd.dd.digest.h[0] = cpu_to_le32 ( 0x67452301 );
152 context->ddd.dd.digest.h[1] = cpu_to_le32 ( 0xefcdab89 );
153 context->ddd.dd.digest.h[2] = cpu_to_le32 ( 0x98badcfe );
154 context->ddd.dd.digest.h[3] = cpu_to_le32 ( 0x10325476 );
155 context->len = 0;
156 }
157
158 /**
159 * Calculate MD5 digest of accumulated data
160 *
161 * @v context MD5 context
162 */
md5_digest(struct md5_context * context)163 static void md5_digest ( struct md5_context *context ) {
164 union {
165 union md5_digest_data_dwords ddd;
166 struct md5_variables v;
167 } u;
168 uint32_t *a = &u.v.a;
169 uint32_t *b = &u.v.b;
170 uint32_t *c = &u.v.c;
171 uint32_t *d = &u.v.d;
172 uint32_t *w = u.v.w;
173 uint32_t f;
174 uint32_t g;
175 uint32_t temp;
176 struct md5_step *step;
177 unsigned int round;
178 unsigned int i;
179
180 /* Sanity checks */
181 assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
182 linker_assert ( &u.ddd.dd.digest.h[0] == a, md5_bad_layout );
183 linker_assert ( &u.ddd.dd.digest.h[1] == b, md5_bad_layout );
184 linker_assert ( &u.ddd.dd.digest.h[2] == c, md5_bad_layout );
185 linker_assert ( &u.ddd.dd.digest.h[3] == d, md5_bad_layout );
186 linker_assert ( &u.ddd.dd.data.dword[0] == w, md5_bad_layout );
187
188 DBGC ( context, "MD5 digesting:\n" );
189 DBGC_HDA ( context, 0, &context->ddd.dd.digest,
190 sizeof ( context->ddd.dd.digest ) );
191 DBGC_HDA ( context, context->len, &context->ddd.dd.data,
192 sizeof ( context->ddd.dd.data ) );
193
194 /* Convert h[0..3] to host-endian, and initialise a, b, c, d,
195 * and w[0..15]
196 */
197 for ( i = 0 ; i < ( sizeof ( u.ddd.dword ) /
198 sizeof ( u.ddd.dword[0] ) ) ; i++ ) {
199 le32_to_cpus ( &context->ddd.dword[i] );
200 u.ddd.dword[i] = context->ddd.dword[i];
201 }
202
203 /* Main loop */
204 for ( i = 0 ; i < 64 ; i++ ) {
205 round = ( i / 16 );
206 step = &md5_steps[round];
207 f = step->f ( &u.v );
208 g = ( ( ( step->coefficient * i ) + step->constant ) % 16 );
209 temp = *d;
210 *d = *c;
211 *c = *b;
212 *b = ( *b + rol32 ( ( *a + f + k[i] + w[g] ),
213 r[round][ i % 4 ] ) );
214 *a = temp;
215 DBGC2 ( context, "%2d : %08x %08x %08x %08x\n",
216 i, *a, *b, *c, *d );
217 }
218
219 /* Add chunk to hash and convert back to little-endian */
220 for ( i = 0 ; i < 4 ; i++ ) {
221 context->ddd.dd.digest.h[i] =
222 cpu_to_le32 ( context->ddd.dd.digest.h[i] +
223 u.ddd.dd.digest.h[i] );
224 }
225
226 DBGC ( context, "MD5 digested:\n" );
227 DBGC_HDA ( context, 0, &context->ddd.dd.digest,
228 sizeof ( context->ddd.dd.digest ) );
229 }
230
231 /**
232 * Accumulate data with MD5 algorithm
233 *
234 * @v ctx MD5 context
235 * @v data Data
236 * @v len Length of data
237 */
md5_update(void * ctx,const void * data,size_t len)238 static void md5_update ( void *ctx, const void *data, size_t len ) {
239 struct md5_context *context = ctx;
240 const uint8_t *byte = data;
241 size_t offset;
242
243 /* Accumulate data a byte at a time, performing the digest
244 * whenever we fill the data buffer
245 */
246 while ( len-- ) {
247 offset = ( context->len % sizeof ( context->ddd.dd.data ) );
248 context->ddd.dd.data.byte[offset] = *(byte++);
249 context->len++;
250 if ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 )
251 md5_digest ( context );
252 }
253 }
254
255 /**
256 * Generate MD5 digest
257 *
258 * @v ctx MD5 context
259 * @v out Output buffer
260 */
md5_final(void * ctx,void * out)261 static void md5_final ( void *ctx, void *out ) {
262 struct md5_context *context = ctx;
263 uint64_t len_bits;
264 uint8_t pad;
265
266 /* Record length before pre-processing */
267 len_bits = cpu_to_le64 ( ( ( uint64_t ) context->len ) * 8 );
268
269 /* Pad with a single "1" bit followed by as many "0" bits as required */
270 pad = 0x80;
271 do {
272 md5_update ( ctx, &pad, sizeof ( pad ) );
273 pad = 0x00;
274 } while ( ( context->len % sizeof ( context->ddd.dd.data ) ) !=
275 offsetof ( typeof ( context->ddd.dd.data ), final.len ) );
276
277 /* Append length (in bits) */
278 md5_update ( ctx, &len_bits, sizeof ( len_bits ) );
279 assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
280
281 /* Copy out final digest */
282 memcpy ( out, &context->ddd.dd.digest,
283 sizeof ( context->ddd.dd.digest ) );
284 }
285
286 /** MD5 algorithm */
287 struct digest_algorithm md5_algorithm = {
288 .name = "md5",
289 .ctxsize = sizeof ( struct md5_context ),
290 .blocksize = sizeof ( union md5_block ),
291 .digestsize = sizeof ( struct md5_digest ),
292 .init = md5_init,
293 .update = md5_update,
294 .final = md5_final,
295 };
296
297 /** "md5" object identifier */
298 static uint8_t oid_md5[] = { ASN1_OID_MD5 };
299
300 /** "md5" OID-identified algorithm */
301 struct asn1_algorithm oid_md5_algorithm __asn1_algorithm = {
302 .name = "md5",
303 .digest = &md5_algorithm,
304 .oid = ASN1_OID_CURSOR ( oid_md5 ),
305 };
306