1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
|
/*
* Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
*
* Licensed under the OpenSSL license (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
/*
* NB: these functions have been "upgraded", the deprecated versions (which
* are compatibility wrappers using these functions) are in rsa_depr.c. -
* Geoff
*/
#include <stdio.h>
#include <time.h>
#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include "rsa_locl.h"
static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
BN_GENCB *cb);
/*
* NB: this wrapper would normally be placed in rsa_lib.c and the static
* implementation would probably be in rsa_eay.c. Nonetheless, is kept here
* so that we don't introduce a new linker dependency. Eg. any application
* that wasn't previously linking object code related to key-generation won't
* have to now just because key-generation is part of RSA_METHOD.
*/
int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
{
if (rsa->meth->rsa_keygen)
return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
return rsa_builtin_keygen(rsa, bits, e_value, cb);
}
static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
BN_GENCB *cb)
{
BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
int bitsp, bitsq, ok = -1, n = 0;
BN_CTX *ctx = NULL;
unsigned long error = 0;
/*
* When generating ridiculously small keys, we can get stuck
* continually regenerating the same prime values.
*/
if (bits < 16) {
ok = 0; /* we set our own err */
RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
r0 = BN_CTX_get(ctx);
r1 = BN_CTX_get(ctx);
r2 = BN_CTX_get(ctx);
r3 = BN_CTX_get(ctx);
if (r3 == NULL)
goto err;
bitsp = (bits + 1) / 2;
bitsq = bits - bitsp;
/* We need the RSA components non-NULL */
if (!rsa->n && ((rsa->n = BN_new()) == NULL))
goto err;
if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL))
goto err;
if (!rsa->e && ((rsa->e = BN_new()) == NULL))
goto err;
if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL))
goto err;
if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL))
goto err;
if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL))
goto err;
if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL))
goto err;
if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL))
goto err;
if (BN_copy(rsa->e, e_value) == NULL)
goto err;
BN_set_flags(r2, BN_FLG_CONSTTIME);
/* generate p and q */
for (;;) {
if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
goto err;
if (!BN_sub(r2, rsa->p, BN_value_one()))
goto err;
ERR_set_mark();
if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) {
/* GCD == 1 since inverse exists */
break;
}
error = ERR_peek_last_error();
if (ERR_GET_LIB(error) == ERR_LIB_BN
&& ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
/* GCD != 1 */
ERR_pop_to_mark();
} else {
goto err;
}
if (!BN_GENCB_call(cb, 2, n++))
goto err;
}
if (!BN_GENCB_call(cb, 3, 0))
goto err;
for (;;) {
do {
if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
goto err;
} while (BN_cmp(rsa->p, rsa->q) == 0);
if (!BN_sub(r2, rsa->q, BN_value_one()))
goto err;
ERR_set_mark();
if (BN_mod_inverse(r1, r2, rsa->e, ctx) != NULL) {
/* GCD == 1 since inverse exists */
break;
}
error = ERR_peek_last_error();
if (ERR_GET_LIB(error) == ERR_LIB_BN
&& ERR_GET_REASON(error) == BN_R_NO_INVERSE) {
/* GCD != 1 */
ERR_pop_to_mark();
} else {
goto err;
}
if (!BN_GENCB_call(cb, 2, n++))
goto err;
}
if (!BN_GENCB_call(cb, 3, 1))
goto err;
if (BN_cmp(rsa->p, rsa->q) < 0) {
tmp = rsa->p;
rsa->p = rsa->q;
rsa->q = tmp;
}
/* calculate n */
if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
goto err;
/* calculate d */
if (!BN_sub(r1, rsa->p, BN_value_one()))
goto err; /* p-1 */
if (!BN_sub(r2, rsa->q, BN_value_one()))
goto err; /* q-1 */
if (!BN_mul(r0, r1, r2, ctx))
goto err; /* (p-1)(q-1) */
{
BIGNUM *pr0 = BN_new();
if (pr0 == NULL)
goto err;
BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) {
BN_free(pr0);
goto err; /* d */
}
/* We MUST free pr0 before any further use of r0 */
BN_free(pr0);
}
{
BIGNUM *d = BN_new();
if (d == NULL)
goto err;
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
if ( /* calculate d mod (p-1) */
!BN_mod(rsa->dmp1, d, r1, ctx)
/* calculate d mod (q-1) */
|| !BN_mod(rsa->dmq1, d, r2, ctx)) {
BN_free(d);
goto err;
}
/* We MUST free d before any further use of rsa->d */
BN_free(d);
}
{
BIGNUM *p = BN_new();
if (p == NULL)
goto err;
BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
/* calculate inverse of q mod p */
if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) {
BN_free(p);
goto err;
}
/* We MUST free p before any further use of rsa->p */
BN_free(p);
}
ok = 1;
err:
if (ok == -1) {
RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN);
ok = 0;
}
if (ctx != NULL)
BN_CTX_end(ctx);
BN_CTX_free(ctx);
return ok;
}
|
