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