[efi] Disable EFI watchdog timer when shutting down to boot an OS
[ipxe.git] / src / crypto / bigint.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 #include <stdint.h>
27 #include <string.h>
28 #include <assert.h>
29 #include <ipxe/profile.h>
30 #include <ipxe/bigint.h>
31
32 /** @file
33 *
34 * Big integer support
35 */
36
37 /** Modular multiplication overall profiler */
38 static struct profiler bigint_mod_multiply_profiler __profiler =
39 { .name = "bigint_mod_multiply" };
40
41 /** Modular multiplication multiply step profiler */
42 static struct profiler bigint_mod_multiply_multiply_profiler __profiler =
43 { .name = "bigint_mod_multiply.multiply" };
44
45 /** Modular multiplication rescale step profiler */
46 static struct profiler bigint_mod_multiply_rescale_profiler __profiler =
47 { .name = "bigint_mod_multiply.rescale" };
48
49 /** Modular multiplication subtract step profiler */
50 static struct profiler bigint_mod_multiply_subtract_profiler __profiler =
51 { .name = "bigint_mod_multiply.subtract" };
52
53 /**
54 * Perform modular multiplication of big integers
55 *
56 * @v multiplicand0 Element 0 of big integer to be multiplied
57 * @v multiplier0 Element 0 of big integer to be multiplied
58 * @v modulus0 Element 0 of big integer modulus
59 * @v result0 Element 0 of big integer to hold result
60 * @v size Number of elements in base, modulus, and result
61 * @v tmp Temporary working space
62 */
63 void bigint_mod_multiply_raw ( const bigint_element_t *multiplicand0,
64 const bigint_element_t *multiplier0,
65 const bigint_element_t *modulus0,
66 bigint_element_t *result0,
67 unsigned int size, void *tmp ) {
68 const bigint_t ( size ) __attribute__ (( may_alias )) *multiplicand =
69 ( ( const void * ) multiplicand0 );
70 const bigint_t ( size ) __attribute__ (( may_alias )) *multiplier =
71 ( ( const void * ) multiplier0 );
72 const bigint_t ( size ) __attribute__ (( may_alias )) *modulus =
73 ( ( const void * ) modulus0 );
74 bigint_t ( size ) __attribute__ (( may_alias )) *result =
75 ( ( void * ) result0 );
76 struct {
77 bigint_t ( size * 2 ) result;
78 bigint_t ( size * 2 ) modulus;
79 } *temp = tmp;
80 int rotation;
81 int i;
82
83 /* Start profiling */
84 profile_start ( &bigint_mod_multiply_profiler );
85
86 /* Sanity check */
87 assert ( sizeof ( *temp ) == bigint_mod_multiply_tmp_len ( modulus ) );
88
89 /* Perform multiplication */
90 profile_start ( &bigint_mod_multiply_multiply_profiler );
91 bigint_multiply ( multiplicand, multiplier, &temp->result );
92 profile_stop ( &bigint_mod_multiply_multiply_profiler );
93
94 /* Rescale modulus to match result */
95 profile_start ( &bigint_mod_multiply_rescale_profiler );
96 bigint_grow ( modulus, &temp->modulus );
97 rotation = ( bigint_max_set_bit ( &temp->result ) -
98 bigint_max_set_bit ( &temp->modulus ) );
99 for ( i = 0 ; i < rotation ; i++ )
100 bigint_rol ( &temp->modulus );
101 profile_stop ( &bigint_mod_multiply_rescale_profiler );
102
103 /* Subtract multiples of modulus */
104 profile_start ( &bigint_mod_multiply_subtract_profiler );
105 for ( i = 0 ; i <= rotation ; i++ ) {
106 if ( bigint_is_geq ( &temp->result, &temp->modulus ) )
107 bigint_subtract ( &temp->modulus, &temp->result );
108 bigint_ror ( &temp->modulus );
109 }
110 profile_stop ( &bigint_mod_multiply_subtract_profiler );
111
112 /* Resize result */
113 bigint_shrink ( &temp->result, result );
114
115 /* Sanity check */
116 assert ( bigint_is_geq ( modulus, result ) );
117
118 /* Stop profiling */
119 profile_stop ( &bigint_mod_multiply_profiler );
120 }
121
122 /**
123 * Perform modular exponentiation of big integers
124 *
125 * @v base0 Element 0 of big integer base
126 * @v modulus0 Element 0 of big integer modulus
127 * @v exponent0 Element 0 of big integer exponent
128 * @v result0 Element 0 of big integer to hold result
129 * @v size Number of elements in base, modulus, and result
130 * @v exponent_size Number of elements in exponent
131 * @v tmp Temporary working space
132 */
133 void bigint_mod_exp_raw ( const bigint_element_t *base0,
134 const bigint_element_t *modulus0,
135 const bigint_element_t *exponent0,
136 bigint_element_t *result0,
137 unsigned int size, unsigned int exponent_size,
138 void *tmp ) {
139 const bigint_t ( size ) __attribute__ (( may_alias )) *base =
140 ( ( const void * ) base0 );
141 const bigint_t ( size ) __attribute__ (( may_alias )) *modulus =
142 ( ( const void * ) modulus0 );
143 const bigint_t ( exponent_size ) __attribute__ (( may_alias ))
144 *exponent = ( ( const void * ) exponent0 );
145 bigint_t ( size ) __attribute__ (( may_alias )) *result =
146 ( ( void * ) result0 );
147 size_t mod_multiply_len = bigint_mod_multiply_tmp_len ( modulus );
148 struct {
149 bigint_t ( size ) base;
150 bigint_t ( exponent_size ) exponent;
151 uint8_t mod_multiply[mod_multiply_len];
152 } *temp = tmp;
153 static const uint8_t start[1] = { 0x01 };
154
155 memcpy ( &temp->base, base, sizeof ( temp->base ) );
156 memcpy ( &temp->exponent, exponent, sizeof ( temp->exponent ) );
157 bigint_init ( result, start, sizeof ( start ) );
158
159 while ( ! bigint_is_zero ( &temp->exponent ) ) {
160 if ( bigint_bit_is_set ( &temp->exponent, 0 ) ) {
161 bigint_mod_multiply ( result, &temp->base, modulus,
162 result, temp->mod_multiply );
163 }
164 bigint_ror ( &temp->exponent );
165 bigint_mod_multiply ( &temp->base, &temp->base, modulus,
166 &temp->base, temp->mod_multiply );
167 }
168 }