[331] | 1 | /*
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| 2 | * Copyright 1995-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | /*
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| 11 | * NB: these functions have been "upgraded", the deprecated versions (which
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| 12 | * are compatibility wrappers using these functions) are in rsa_depr.c. -
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| 13 | * Geoff
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| 14 | */
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| 15 |
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| 16 | #include <stdio.h>
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| 17 | #include <time.h>
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| 18 | #include "internal/cryptlib.h"
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| 19 | #include <openssl/bn.h>
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| 20 | #include "rsa_locl.h"
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| 21 |
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| 22 | static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
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| 23 | BN_GENCB *cb);
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| 24 |
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| 25 | /*
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| 26 | * NB: this wrapper would normally be placed in rsa_lib.c and the static
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| 27 | * implementation would probably be in rsa_eay.c. Nonetheless, is kept here
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| 28 | * so that we don't introduce a new linker dependency. Eg. any application
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| 29 | * that wasn't previously linking object code related to key-generation won't
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| 30 | * have to now just because key-generation is part of RSA_METHOD.
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| 31 | */
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| 32 | int RSA_generate_key_ex(RSA *rsa, int bits, BIGNUM *e_value, BN_GENCB *cb)
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| 33 | {
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| 34 | if (rsa->meth->rsa_keygen)
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| 35 | return rsa->meth->rsa_keygen(rsa, bits, e_value, cb);
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| 36 | return rsa_builtin_keygen(rsa, bits, e_value, cb);
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| 37 | }
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| 38 |
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| 39 | static int rsa_builtin_keygen(RSA *rsa, int bits, BIGNUM *e_value,
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| 40 | BN_GENCB *cb)
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| 41 | {
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| 42 | BIGNUM *r0 = NULL, *r1 = NULL, *r2 = NULL, *r3 = NULL, *tmp;
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| 43 | int bitsp, bitsq, ok = -1, n = 0;
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| 44 | BN_CTX *ctx = NULL;
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| 45 |
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| 46 | ctx = BN_CTX_new();
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| 47 | if (ctx == NULL)
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| 48 | goto err;
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| 49 | BN_CTX_start(ctx);
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| 50 | r0 = BN_CTX_get(ctx);
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| 51 | r1 = BN_CTX_get(ctx);
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| 52 | r2 = BN_CTX_get(ctx);
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| 53 | r3 = BN_CTX_get(ctx);
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| 54 | if (r3 == NULL)
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| 55 | goto err;
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| 56 |
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| 57 | bitsp = (bits + 1) / 2;
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| 58 | bitsq = bits - bitsp;
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| 59 |
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| 60 | /* We need the RSA components non-NULL */
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| 61 | if (!rsa->n && ((rsa->n = BN_new()) == NULL))
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| 62 | goto err;
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| 63 | if (!rsa->d && ((rsa->d = BN_secure_new()) == NULL))
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| 64 | goto err;
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| 65 | if (!rsa->e && ((rsa->e = BN_new()) == NULL))
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| 66 | goto err;
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| 67 | if (!rsa->p && ((rsa->p = BN_secure_new()) == NULL))
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| 68 | goto err;
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| 69 | if (!rsa->q && ((rsa->q = BN_secure_new()) == NULL))
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| 70 | goto err;
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| 71 | if (!rsa->dmp1 && ((rsa->dmp1 = BN_secure_new()) == NULL))
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| 72 | goto err;
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| 73 | if (!rsa->dmq1 && ((rsa->dmq1 = BN_secure_new()) == NULL))
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| 74 | goto err;
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| 75 | if (!rsa->iqmp && ((rsa->iqmp = BN_secure_new()) == NULL))
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| 76 | goto err;
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| 77 |
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| 78 | if (BN_copy(rsa->e, e_value) == NULL)
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| 79 | goto err;
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| 80 |
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| 81 | /* generate p and q */
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| 82 | for (;;) {
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| 83 | if (!BN_generate_prime_ex(rsa->p, bitsp, 0, NULL, NULL, cb))
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| 84 | goto err;
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| 85 | if (!BN_sub(r2, rsa->p, BN_value_one()))
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| 86 | goto err;
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| 87 | if (!BN_gcd(r1, r2, rsa->e, ctx))
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| 88 | goto err;
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| 89 | if (BN_is_one(r1))
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| 90 | break;
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| 91 | if (!BN_GENCB_call(cb, 2, n++))
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| 92 | goto err;
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| 93 | }
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| 94 | if (!BN_GENCB_call(cb, 3, 0))
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| 95 | goto err;
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| 96 | for (;;) {
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| 97 | /*
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| 98 | * When generating ridiculously small keys, we can get stuck
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| 99 | * continually regenerating the same prime values. Check for this and
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| 100 | * bail if it happens 3 times.
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| 101 | */
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| 102 | unsigned int degenerate = 0;
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| 103 | do {
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| 104 | if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL, cb))
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| 105 | goto err;
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| 106 | } while ((BN_cmp(rsa->p, rsa->q) == 0) && (++degenerate < 3));
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| 107 | if (degenerate == 3) {
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| 108 | ok = 0; /* we set our own err */
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| 109 | RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, RSA_R_KEY_SIZE_TOO_SMALL);
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| 110 | goto err;
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| 111 | }
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| 112 | if (!BN_sub(r2, rsa->q, BN_value_one()))
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| 113 | goto err;
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| 114 | if (!BN_gcd(r1, r2, rsa->e, ctx))
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| 115 | goto err;
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| 116 | if (BN_is_one(r1))
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| 117 | break;
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| 118 | if (!BN_GENCB_call(cb, 2, n++))
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| 119 | goto err;
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| 120 | }
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| 121 | if (!BN_GENCB_call(cb, 3, 1))
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| 122 | goto err;
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| 123 | if (BN_cmp(rsa->p, rsa->q) < 0) {
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| 124 | tmp = rsa->p;
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| 125 | rsa->p = rsa->q;
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| 126 | rsa->q = tmp;
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| 127 | }
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| 128 |
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| 129 | /* calculate n */
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| 130 | if (!BN_mul(rsa->n, rsa->p, rsa->q, ctx))
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| 131 | goto err;
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| 132 |
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| 133 | /* calculate d */
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| 134 | if (!BN_sub(r1, rsa->p, BN_value_one()))
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| 135 | goto err; /* p-1 */
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| 136 | if (!BN_sub(r2, rsa->q, BN_value_one()))
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| 137 | goto err; /* q-1 */
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| 138 | if (!BN_mul(r0, r1, r2, ctx))
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| 139 | goto err; /* (p-1)(q-1) */
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| 140 | {
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| 141 | BIGNUM *pr0 = BN_new();
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| 142 |
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| 143 | if (pr0 == NULL)
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| 144 | goto err;
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| 145 | BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
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| 146 | if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) {
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| 147 | BN_free(pr0);
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| 148 | goto err; /* d */
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| 149 | }
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| 150 | /* We MUST free pr0 before any further use of r0 */
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| 151 | BN_free(pr0);
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| 152 | }
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| 153 |
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| 154 | {
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| 155 | BIGNUM *d = BN_new();
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| 156 |
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| 157 | if (d == NULL)
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| 158 | goto err;
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| 159 | BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
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| 160 |
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| 161 | if ( /* calculate d mod (p-1) */
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| 162 | !BN_mod(rsa->dmp1, d, r1, ctx)
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| 163 | /* calculate d mod (q-1) */
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| 164 | || !BN_mod(rsa->dmq1, d, r2, ctx)) {
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| 165 | BN_free(d);
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| 166 | goto err;
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| 167 | }
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| 168 | /* We MUST free d before any further use of rsa->d */
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| 169 | BN_free(d);
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| 170 | }
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| 171 |
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| 172 | {
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| 173 | BIGNUM *p = BN_new();
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| 174 |
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| 175 | if (p == NULL)
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| 176 | goto err;
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| 177 | BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
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| 178 |
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| 179 | /* calculate inverse of q mod p */
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| 180 | if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx)) {
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| 181 | BN_free(p);
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| 182 | goto err;
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| 183 | }
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| 184 | /* We MUST free p before any further use of rsa->p */
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| 185 | BN_free(p);
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| 186 | }
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| 187 |
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| 188 | ok = 1;
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| 189 | err:
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| 190 | if (ok == -1) {
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| 191 | RSAerr(RSA_F_RSA_BUILTIN_KEYGEN, ERR_LIB_BN);
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| 192 | ok = 0;
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| 193 | }
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| 194 | if (ctx != NULL)
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| 195 | BN_CTX_end(ctx);
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| 196 | BN_CTX_free(ctx);
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| 197 |
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| 198 | return ok;
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| 199 | }
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