/* crypto/dsa/dsa_ossl.c *//* 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.] *//* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */#include <stdio.h>#include "cryptlib.h"#include <openssl/bn.h>#include <openssl/dsa.h>#include <openssl/rand.h>#include <openssl/asn1.h>#ifndef OPENSSL_FIPSstatic DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa);static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp);static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,		  DSA *dsa);static int dsa_init(DSA *dsa);static int dsa_finish(DSA *dsa);static DSA_METHOD openssl_dsa_meth = {"OpenSSL DSA method",dsa_do_sign,dsa_sign_setup,dsa_do_verify,NULL, /* dsa_mod_exp, */NULL, /* dsa_bn_mod_exp, */dsa_init,dsa_finish,0,NULL,NULL,NULL};/* These macro wrappers replace attempts to use the dsa_mod_exp() and * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of * having a the macro work as an expression by bundling an "err_instr". So; *  *     if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, *                 dsa->method_mont_p)) goto err; * * can be replaced by; * *     DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, *                 dsa->method_mont_p); */#define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \	do { \	int _tmp_res53; \	if((dsa)->meth->dsa_mod_exp) \		_tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \				(a2), (p2), (m), (ctx), (in_mont)); \	else \		_tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \				(m), (ctx), (in_mont)); \	if(!_tmp_res53) err_instr; \	} while(0)#define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \	do { \	int _tmp_res53; \	if((dsa)->meth->bn_mod_exp) \		_tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \				(m), (ctx), (m_ctx)); \	else \		_tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \	if(!_tmp_res53) err_instr; \	} while(0)const DSA_METHOD *DSA_OpenSSL(void){	return &openssl_dsa_meth;}static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa)	{	BIGNUM *kinv=NULL,*r=NULL,*s=NULL;	BIGNUM m;	BIGNUM xr;	BN_CTX *ctx=NULL;	int i,reason=ERR_R_BN_LIB;	DSA_SIG *ret=NULL;	BN_init(&m);	BN_init(&xr);	if (!dsa->p || !dsa->q || !dsa->g)		{		reason=DSA_R_MISSING_PARAMETERS;		goto err;		}	s=BN_new();	if (s == NULL) goto err;	i=BN_num_bytes(dsa->q); /* should be 20 */	if ((dlen > i) || (dlen > 50))		{		reason=DSA_R_DATA_TOO_LARGE_FOR_KEY_SIZE;		goto err;		}	ctx=BN_CTX_new();	if (ctx == NULL) goto err;	if ((dsa->kinv == NULL) || (dsa->r == NULL))		{		if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err;		}	else		{		kinv=dsa->kinv;		dsa->kinv=NULL;		r=dsa->r;		dsa->r=NULL;		}	if (BN_bin2bn(dgst,dlen,&m) == NULL) goto err;	/* Compute  s = inv(k) (m + xr) mod q */	if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */	if (!BN_add(s, &xr, &m)) goto err;		/* s = m + xr */	if (BN_cmp(s,dsa->q) > 0)		BN_sub(s,s,dsa->q);	if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err;	ret=DSA_SIG_new();	if (ret == NULL) goto err;	ret->r = r;	ret->s = s;	err:	if (!ret)		{		DSAerr(DSA_F_DSA_DO_SIGN,reason);		BN_free(r);		BN_free(s);		}	if (ctx != NULL) BN_CTX_free(ctx);	BN_clear_free(&m);	BN_clear_free(&xr);	if (kinv != NULL) /* dsa->kinv is NULL now if we used it */	    BN_clear_free(kinv);	return(ret);	}static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)	{	BN_CTX *ctx;	BIGNUM k,kq,*K,*kinv=NULL,*r=NULL;	int ret=0;	if (!dsa->p || !dsa->q || !dsa->g)		{		DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS);		return 0;		}	BN_init(&k);	BN_init(&kq);	if (ctx_in == NULL)		{		if ((ctx=BN_CTX_new()) == NULL) goto err;		}	else		ctx=ctx_in;	if ((r=BN_new()) == NULL) goto err;	/* Get random k */	do		if (!BN_rand_range(&k, dsa->q)) goto err;	while (BN_is_zero(&k));	if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)		{		BN_set_flags(&k, BN_FLG_CONSTTIME);		}	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)		{		if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p,						CRYPTO_LOCK_DSA,						dsa->p, ctx))			goto err;		}	/* Compute r = (g^k mod p) mod q */	if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0)		{		if (!BN_copy(&kq, &k)) goto err;		/* We do not want timing information to leak the length of k,		 * so we compute g^k using an equivalent exponent of fixed length.		 *		 * (This is a kludge that we need because the BN_mod_exp_mont()		 * does not let us specify the desired timing behaviour.) */		if (!BN_add(&kq, &kq, dsa->q)) goto err;		if (BN_num_bits(&kq) <= BN_num_bits(dsa->q))			{			if (!BN_add(&kq, &kq, dsa->q)) goto err;			}		K = &kq;		}	else		{		K = &k;		}	DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx,			dsa->method_mont_p);	if (!BN_mod(r,r,dsa->q,ctx)) goto err;	/* Compute  part of 's = inv(k) (m + xr) mod q' */	if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err;	if (*kinvp != NULL) BN_clear_free(*kinvp);	*kinvp=kinv;	kinv=NULL;	if (*rp != NULL) BN_clear_free(*rp);	*rp=r;	ret=1;err:	if (!ret)		{		DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB);		if (kinv != NULL) BN_clear_free(kinv);		if (r != NULL) BN_clear_free(r);		}	if (ctx_in == NULL) BN_CTX_free(ctx);	if (kinv != NULL) BN_clear_free(kinv);	BN_clear_free(&k);	BN_clear_free(&kq);	return(ret);	}static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,		  DSA *dsa)	{	BN_CTX *ctx;	BIGNUM u1,u2,t1;	BN_MONT_CTX *mont=NULL;	int ret = -1;	if (!dsa->p || !dsa->q || !dsa->g)		{		DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS);		return -1;		}	if (BN_num_bits(dsa->q) != 160)		{		DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE);		return -1;		}	if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS)		{		DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE);		return -1;		}	BN_init(&u1);	BN_init(&u2);	BN_init(&t1);	if ((ctx=BN_CTX_new()) == NULL) goto err;	if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||	    BN_ucmp(sig->r, dsa->q) >= 0)		{		ret = 0;		goto err;		}	if (BN_is_zero(sig->s) || BN_is_negative(sig->s) ||	    BN_ucmp(sig->s, dsa->q) >= 0)		{		ret = 0;		goto err;		}	/* Calculate W = inv(S) mod Q	 * save W in u2 */	if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err;	/* save M in u1 */	if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err;	/* u1 = M * w mod q */	if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err;	/* u2 = r * w mod q */	if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err;	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)		{		mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p,					CRYPTO_LOCK_DSA, dsa->p, ctx);		if (!mont)			goto err;		}	DSA_MOD_EXP(goto err, dsa, &t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p, ctx, mont);	/* BN_copy(&u1,&t1); */	/* let u1 = u1 mod q */	if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err;	/* V is now in u1.  If the signature is correct, it will be	 * equal to R. */	ret=(BN_ucmp(&u1, sig->r) == 0);	err:	/* XXX: surely this is wrong - if ret is 0, it just didn't verify;	   there is no error in BN. Test should be ret == -1 (Ben) */	if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB);	if (ctx != NULL) BN_CTX_free(ctx);	BN_free(&u1);	BN_free(&u2);	BN_free(&t1);	return(ret);	}static int dsa_init(DSA *dsa){	dsa->flags|=DSA_FLAG_CACHE_MONT_P;	return(1);}static int dsa_finish(DSA *dsa){	if(dsa->method_mont_p)		BN_MONT_CTX_free(dsa->method_mont_p);	return(1);}#endif