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/* $OpenBSD: rsa_gen.c,v 1.17 2015/02/09 15:49:22 jsing Exp $ */
/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
* All rights reserved.
*
* This package is an SSL implementation written
* by Eric Young (eay@cryptsoft.com).
* The implementation was written so as to conform with Netscapes SSL.
*
* This library is free for commercial and non-commercial use as long as
* the following conditions are aheared to. The following conditions
* apply to all code found in this distribution, be it the RC4, RSA,
* lhash, DES, etc., code; not just the SSL code. The SSL documentation
* included with this distribution is covered by the same copyright terms
* except that the holder is Tim Hudson (tjh@cryptsoft.com).
*
* Copyright remains Eric Young's, and as such any Copyright notices in
* the code are not to be removed.
* If this package is used in a product, Eric Young should be given attribution
* as the author of the parts of the library used.
* This can be in the form of a textual message at program startup or
* in documentation (online or textual) provided with the package.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* "This product includes cryptographic software written by
* Eric Young (eay@cryptsoft.com)"
* The word 'cryptographic' can be left out if the rouines from the library
* being used are not cryptographic related :-).
* 4. If you include any Windows specific code (or a derivative thereof) from
* the apps directory (application code) you must include an acknowledgement:
* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
*
* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* The licence and distribution terms for any publically available version or
* derivative of this code cannot be changed. i.e. this code cannot simply be
* copied and put under another distribution licence
* [including the GNU Public Licence.]
*/
/* 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 <openssl/bn.h>
#include <openssl/err.h>
#include <openssl/rsa.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;
BIGNUM local_r0, local_d, local_p;
BIGNUM *pr0, *d, *p;
int bitsp, bitsq, ok = -1, n = 0;
BN_CTX *ctx = NULL;
ctx = BN_CTX_new();
if (ctx == NULL)
goto err;
BN_CTX_start(ctx);
if ((r0 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((r1 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((r2 = BN_CTX_get(ctx)) == NULL)
goto err;
if ((r3 = BN_CTX_get(ctx)) == 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_new()) == NULL))
goto err;
if (!rsa->e && ((rsa->e = BN_new()) == NULL))
goto err;
if (!rsa->p && ((rsa->p = BN_new()) == NULL))
goto err;
if (!rsa->q && ((rsa->q = BN_new()) == NULL))
goto err;
if (!rsa->dmp1 && ((rsa->dmp1 = BN_new()) == NULL))
goto err;
if (!rsa->dmq1 && ((rsa->dmq1 = BN_new()) == NULL))
goto err;
if (!rsa->iqmp && ((rsa->iqmp = BN_new()) == NULL))
goto err;
BN_copy(rsa->e, e_value);
/* 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;
if (!BN_gcd(r1, r2, rsa->e, ctx))
goto err;
if (BN_is_one(r1))
break;
if (!BN_GENCB_call(cb, 2, n++))
goto err;
}
if (!BN_GENCB_call(cb, 3, 0))
goto err;
for (;;) {
/*
* When generating ridiculously small keys, we can get stuck
* continually regenerating the same prime values. Check for
* this and bail if it happens 3 times.
*/
unsigned int degenerate = 0;
do {
if (!BN_generate_prime_ex(rsa->q, bitsq, 0, NULL, NULL,
cb))
goto err;
} while (BN_cmp(rsa->p, rsa->q) == 0 &&
++degenerate < 3);
if (degenerate == 3) {
ok = 0; /* we set our own err */
RSAerr(RSA_F_RSA_BUILTIN_KEYGEN,
RSA_R_KEY_SIZE_TOO_SMALL);
goto err;
}
if (!BN_sub(r2, rsa->q, BN_value_one()))
goto err;
if (!BN_gcd(r1, r2, rsa->e, ctx))
goto err;
if (BN_is_one(r1))
break;
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())) /* p-1 */
goto err;
if (!BN_sub(r2, rsa->q, BN_value_one())) /* q-1 */
goto err;
if (!BN_mul(r0, r1, r2, ctx)) /* (p-1)(q-1) */
goto err;
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
pr0 = &local_r0;
BN_with_flags(pr0, r0, BN_FLG_CONSTTIME);
} else
pr0 = r0;
if (!BN_mod_inverse(rsa->d, rsa->e, pr0, ctx)) /* d */
goto err;
/* set up d for correct BN_FLG_CONSTTIME flag */
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
d = &local_d;
BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
} else
d = rsa->d;
/* calculate d mod (p-1) */
if (!BN_mod(rsa->dmp1, d, r1, ctx))
goto err;
/* calculate d mod (q-1) */
if (!BN_mod(rsa->dmq1, d, r2, ctx))
goto err;
/* calculate inverse of q mod p */
if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
p = &local_p;
BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
} else
p = rsa->p;
if (!BN_mod_inverse(rsa->iqmp, rsa->q, p, ctx))
goto err;
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;
}
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