[efi] Disable EFI watchdog timer when shutting down to boot an OS
[ipxe.git] / src / crypto / sha256.c
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 * SHA-256 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/sha256.h>
39
40 /** SHA-256 variables */
41 struct sha256_variables {
42 /* This layout matches that of struct sha256_digest_data,
43 * allowing for efficient endianness-conversion,
44 */
45 uint32_t a;
46 uint32_t b;
47 uint32_t c;
48 uint32_t d;
49 uint32_t e;
50 uint32_t f;
51 uint32_t g;
52 uint32_t h;
53 uint32_t w[SHA256_ROUNDS];
54 } __attribute__ (( packed ));
55
56 /** SHA-256 constants */
57 static const uint32_t k[SHA256_ROUNDS] = {
58 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1,
59 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
60 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786,
61 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
62 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147,
63 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
64 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b,
65 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
66 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a,
67 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
68 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
69 };
70
71 /** SHA-256 initial digest values */
72 static const struct sha256_digest sha256_init_digest = {
73 .h = {
74 cpu_to_be32 ( 0x6a09e667 ),
75 cpu_to_be32 ( 0xbb67ae85 ),
76 cpu_to_be32 ( 0x3c6ef372 ),
77 cpu_to_be32 ( 0xa54ff53a ),
78 cpu_to_be32 ( 0x510e527f ),
79 cpu_to_be32 ( 0x9b05688c ),
80 cpu_to_be32 ( 0x1f83d9ab ),
81 cpu_to_be32 ( 0x5be0cd19 ),
82 },
83 };
84
85 /**
86 * Initialise SHA-256 family algorithm
87 *
88 * @v context SHA-256 context
89 * @v init Initial digest values
90 * @v digestsize Digest size
91 */
92 void sha256_family_init ( struct sha256_context *context,
93 const struct sha256_digest *init,
94 size_t digestsize ) {
95
96 context->len = 0;
97 context->digestsize = digestsize;
98 memcpy ( &context->ddd.dd.digest, init,
99 sizeof ( context->ddd.dd.digest ) );
100 }
101
102 /**
103 * Initialise SHA-256 algorithm
104 *
105 * @v ctx SHA-256 context
106 */
107 static void sha256_init ( void *ctx ) {
108 struct sha256_context *context = ctx;
109
110 sha256_family_init ( context, &sha256_init_digest,
111 sizeof ( struct sha256_digest ) );
112 }
113
114 /**
115 * Calculate SHA-256 digest of accumulated data
116 *
117 * @v context SHA-256 context
118 */
119 static void sha256_digest ( struct sha256_context *context ) {
120 union {
121 union sha256_digest_data_dwords ddd;
122 struct sha256_variables v;
123 } u;
124 uint32_t *a = &u.v.a;
125 uint32_t *b = &u.v.b;
126 uint32_t *c = &u.v.c;
127 uint32_t *d = &u.v.d;
128 uint32_t *e = &u.v.e;
129 uint32_t *f = &u.v.f;
130 uint32_t *g = &u.v.g;
131 uint32_t *h = &u.v.h;
132 uint32_t *w = u.v.w;
133 uint32_t s0;
134 uint32_t s1;
135 uint32_t maj;
136 uint32_t t1;
137 uint32_t t2;
138 uint32_t ch;
139 unsigned int i;
140
141 /* Sanity checks */
142 assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
143 linker_assert ( &u.ddd.dd.digest.h[0] == a, sha256_bad_layout );
144 linker_assert ( &u.ddd.dd.digest.h[1] == b, sha256_bad_layout );
145 linker_assert ( &u.ddd.dd.digest.h[2] == c, sha256_bad_layout );
146 linker_assert ( &u.ddd.dd.digest.h[3] == d, sha256_bad_layout );
147 linker_assert ( &u.ddd.dd.digest.h[4] == e, sha256_bad_layout );
148 linker_assert ( &u.ddd.dd.digest.h[5] == f, sha256_bad_layout );
149 linker_assert ( &u.ddd.dd.digest.h[6] == g, sha256_bad_layout );
150 linker_assert ( &u.ddd.dd.digest.h[7] == h, sha256_bad_layout );
151 linker_assert ( &u.ddd.dd.data.dword[0] == w, sha256_bad_layout );
152
153 DBGC ( context, "SHA256 digesting:\n" );
154 DBGC_HDA ( context, 0, &context->ddd.dd.digest,
155 sizeof ( context->ddd.dd.digest ) );
156 DBGC_HDA ( context, context->len, &context->ddd.dd.data,
157 sizeof ( context->ddd.dd.data ) );
158
159 /* Convert h[0..7] to host-endian, and initialise a, b, c, d,
160 * e, f, g, h, and w[0..15]
161 */
162 for ( i = 0 ; i < ( sizeof ( u.ddd.dword ) /
163 sizeof ( u.ddd.dword[0] ) ) ; i++ ) {
164 be32_to_cpus ( &context->ddd.dword[i] );
165 u.ddd.dword[i] = context->ddd.dword[i];
166 }
167
168 /* Initialise w[16..63] */
169 for ( i = 16 ; i < SHA256_ROUNDS ; i++ ) {
170 s0 = ( ror32 ( w[i-15], 7 ) ^ ror32 ( w[i-15], 18 ) ^
171 ( w[i-15] >> 3 ) );
172 s1 = ( ror32 ( w[i-2], 17 ) ^ ror32 ( w[i-2], 19 ) ^
173 ( w[i-2] >> 10 ) );
174 w[i] = ( w[i-16] + s0 + w[i-7] + s1 );
175 }
176
177 /* Main loop */
178 for ( i = 0 ; i < SHA256_ROUNDS ; i++ ) {
179 s0 = ( ror32 ( *a, 2 ) ^ ror32 ( *a, 13 ) ^ ror32 ( *a, 22 ) );
180 maj = ( ( *a & *b ) ^ ( *a & *c ) ^ ( *b & *c ) );
181 t2 = ( s0 + maj );
182 s1 = ( ror32 ( *e, 6 ) ^ ror32 ( *e, 11 ) ^ ror32 ( *e, 25 ) );
183 ch = ( ( *e & *f ) ^ ( (~*e) & *g ) );
184 t1 = ( *h + s1 + ch + k[i] + w[i] );
185 *h = *g;
186 *g = *f;
187 *f = *e;
188 *e = ( *d + t1 );
189 *d = *c;
190 *c = *b;
191 *b = *a;
192 *a = ( t1 + t2 );
193 DBGC2 ( context, "%2d : %08x %08x %08x %08x %08x %08x %08x "
194 "%08x\n", i, *a, *b, *c, *d, *e, *f, *g, *h );
195 }
196
197 /* Add chunk to hash and convert back to big-endian */
198 for ( i = 0 ; i < 8 ; i++ ) {
199 context->ddd.dd.digest.h[i] =
200 cpu_to_be32 ( context->ddd.dd.digest.h[i] +
201 u.ddd.dd.digest.h[i] );
202 }
203
204 DBGC ( context, "SHA256 digested:\n" );
205 DBGC_HDA ( context, 0, &context->ddd.dd.digest,
206 sizeof ( context->ddd.dd.digest ) );
207 }
208
209 /**
210 * Accumulate data with SHA-256 algorithm
211 *
212 * @v ctx SHA-256 context
213 * @v data Data
214 * @v len Length of data
215 */
216 void sha256_update ( void *ctx, const void *data, size_t len ) {
217 struct sha256_context *context = ctx;
218 const uint8_t *byte = data;
219 size_t offset;
220
221 /* Accumulate data a byte at a time, performing the digest
222 * whenever we fill the data buffer
223 */
224 while ( len-- ) {
225 offset = ( context->len % sizeof ( context->ddd.dd.data ) );
226 context->ddd.dd.data.byte[offset] = *(byte++);
227 context->len++;
228 if ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 )
229 sha256_digest ( context );
230 }
231 }
232
233 /**
234 * Generate SHA-256 digest
235 *
236 * @v ctx SHA-256 context
237 * @v out Output buffer
238 */
239 void sha256_final ( void *ctx, void *out ) {
240 struct sha256_context *context = ctx;
241 uint64_t len_bits;
242 uint8_t pad;
243
244 /* Record length before pre-processing */
245 len_bits = cpu_to_be64 ( ( ( uint64_t ) context->len ) * 8 );
246
247 /* Pad with a single "1" bit followed by as many "0" bits as required */
248 pad = 0x80;
249 do {
250 sha256_update ( ctx, &pad, sizeof ( pad ) );
251 pad = 0x00;
252 } while ( ( context->len % sizeof ( context->ddd.dd.data ) ) !=
253 offsetof ( typeof ( context->ddd.dd.data ), final.len ) );
254
255 /* Append length (in bits) */
256 sha256_update ( ctx, &len_bits, sizeof ( len_bits ) );
257 assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 );
258
259 /* Copy out final digest */
260 memcpy ( out, &context->ddd.dd.digest, context->digestsize );
261 }
262
263 /** SHA-256 algorithm */
264 struct digest_algorithm sha256_algorithm = {
265 .name = "sha256",
266 .ctxsize = sizeof ( struct sha256_context ),
267 .blocksize = sizeof ( union sha256_block ),
268 .digestsize = sizeof ( struct sha256_digest ),
269 .init = sha256_init,
270 .update = sha256_update,
271 .final = sha256_final,
272 };