rsa_eay.c

OpenSSL 0.9.8k 最新版OpenSSL

		BN_sub(f, rsa->n, ret);
		if (BN_cmp(ret, f))
			res = f;
		else
			res = ret;
		}
	else
		res = ret;

	/* put in leading 0 bytes if the number is less than the
	 * length of the modulus */
	j=BN_num_bytes(res);
	i=BN_bn2bin(res,&(to[num-j]));
	for (k=0; k<(num-i); k++)
		to[k]=0;

	r=num;
err:
	if (ctx != NULL)
		{
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
		}
	if (buf != NULL)
		{
		OPENSSL_cleanse(buf,num);
		OPENSSL_free(buf);
		}
	return(r);
	}

static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
	     unsigned char *to, RSA *rsa, int padding)
	{
	BIGNUM *f, *ret, *br;
	int j,num=0,r= -1;
	unsigned char *p;
	unsigned char *buf=NULL;
	BN_CTX *ctx=NULL;
	int local_blinding = 0;
	BN_BLINDING *blinding = NULL;

	if((ctx = BN_CTX_new()) == NULL) goto err;
	BN_CTX_start(ctx);
	f   = BN_CTX_get(ctx);
	br  = BN_CTX_get(ctx);
	ret = BN_CTX_get(ctx);
	num = BN_num_bytes(rsa->n);
	buf = OPENSSL_malloc(num);
	if(!f || !ret || !buf)
		{
		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
		goto err;
		}

	/* This check was for equality but PGP does evil things
	 * and chops off the top '0' bytes */
	if (flen > num)
		{
		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
		goto err;
		}

	/* make data into a big number */
	if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;

	if (BN_ucmp(f, rsa->n) >= 0)
		{
		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
		goto err;
		}

	if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
		{
		blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
		if (blinding == NULL)
			{
			RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
			goto err;
			}
		}
	
	if (blinding != NULL)
		if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
			goto err;

	/* do the decrypt */
	if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
		((rsa->p != NULL) &&
		(rsa->q != NULL) &&
		(rsa->dmp1 != NULL) &&
		(rsa->dmq1 != NULL) &&
		(rsa->iqmp != NULL)) )
		{
		if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
		}
	else
		{
		BIGNUM local_d;
		BIGNUM *d = NULL;
		
		if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
			{
			d = &local_d;
			BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
			}
		else
			d = rsa->d;

		if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
			if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
				goto err;
		if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
				rsa->_method_mod_n))
		  goto err;
		}

	if (blinding)
		if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
			goto err;

	p=buf;
	j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */

	switch (padding)
		{
	case RSA_PKCS1_PADDING:
		r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
		break;
#ifndef OPENSSL_NO_SHA
        case RSA_PKCS1_OAEP_PADDING:
	        r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
                break;
#endif
 	case RSA_SSLV23_PADDING:
		r=RSA_padding_check_SSLv23(to,num,buf,j,num);
		break;
	case RSA_NO_PADDING:
		r=RSA_padding_check_none(to,num,buf,j,num);
		break;
	default:
		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
		goto err;
		}
	if (r < 0)
		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);

err:
	if (ctx != NULL)
		{
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
		}
	if (buf != NULL)
		{
		OPENSSL_cleanse(buf,num);
		OPENSSL_free(buf);
		}
	return(r);
	}

/* signature verification */
static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
	     unsigned char *to, RSA *rsa, int padding)
	{
	BIGNUM *f,*ret;
	int i,num=0,r= -1;
	unsigned char *p;
	unsigned char *buf=NULL;
	BN_CTX *ctx=NULL;

	if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS)
		{
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
		return -1;
		}

	if (BN_ucmp(rsa->n, rsa->e) <= 0)
		{
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
		return -1;
		}

	/* for large moduli, enforce exponent limit */
	if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS)
		{
		if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS)
			{
			RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
			return -1;
			}
		}
	
	if((ctx = BN_CTX_new()) == NULL) goto err;
	BN_CTX_start(ctx);
	f = BN_CTX_get(ctx);
	ret = BN_CTX_get(ctx);
	num=BN_num_bytes(rsa->n);
	buf = OPENSSL_malloc(num);
	if(!f || !ret || !buf)
		{
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
		goto err;
		}

	/* This check was for equality but PGP does evil things
	 * and chops off the top '0' bytes */
	if (flen > num)
		{
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_GREATER_THAN_MOD_LEN);
		goto err;
		}

	if (BN_bin2bn(from,flen,f) == NULL) goto err;

	if (BN_ucmp(f, rsa->n) >= 0)
		{
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
		goto err;
		}

	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
			goto err;

	if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
		rsa->_method_mod_n)) goto err;

	if ((padding == RSA_X931_PADDING) && ((ret->d[0] & 0xf) != 12))
		BN_sub(ret, rsa->n, ret);

	p=buf;
	i=BN_bn2bin(ret,p);

	switch (padding)
		{
	case RSA_PKCS1_PADDING:
		r=RSA_padding_check_PKCS1_type_1(to,num,buf,i,num);
		break;
	case RSA_X931_PADDING:
		r=RSA_padding_check_X931(to,num,buf,i,num);
		break;
	case RSA_NO_PADDING:
		r=RSA_padding_check_none(to,num,buf,i,num);
		break;
	default:
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
		goto err;
		}
	if (r < 0)
		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);

err:
	if (ctx != NULL)
		{
		BN_CTX_end(ctx);
		BN_CTX_free(ctx);
		}
	if (buf != NULL)
		{
		OPENSSL_cleanse(buf,num);
		OPENSSL_free(buf);
		}
	return(r);
	}

static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
	{
	BIGNUM *r1,*m1,*vrfy;
	BIGNUM local_dmp1,local_dmq1,local_c,local_r1;
	BIGNUM *dmp1,*dmq1,*c,*pr1;
	int ret=0;

	BN_CTX_start(ctx);
	r1 = BN_CTX_get(ctx);
	m1 = BN_CTX_get(ctx);
	vrfy = BN_CTX_get(ctx);

	{
		BIGNUM local_p, local_q;
		BIGNUM *p = NULL, *q = NULL;

		/* Make sure BN_mod_inverse in Montgomery intialization uses the
		 * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
		 */
		if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
			{
			BN_init(&local_p);
			p = &local_p;
			BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);

			BN_init(&local_q);
			q = &local_q;
			BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
			}
		else
			{
			p = rsa->p;
			q = rsa->q;
			}

		if (rsa->flags & RSA_FLAG_CACHE_PRIVATE)
			{
			if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx))
				goto err;
			if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q, CRYPTO_LOCK_RSA, q, ctx))
				goto err;
			}
	}

	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
			goto err;

	/* compute I mod q */
	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
		{
		c = &local_c;
		BN_with_flags(c, I, BN_FLG_CONSTTIME);
		if (!BN_mod(r1,c,rsa->q,ctx)) goto err;
		}
	else
		{
		if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
		}

	/* compute r1^dmq1 mod q */
	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
		{
		dmq1 = &local_dmq1;
		BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
		}
	else
		dmq1 = rsa->dmq1;
	if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
		rsa->_method_mod_q)) goto err;

	/* compute I mod p */
	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
		{
		c = &local_c;
		BN_with_flags(c, I, BN_FLG_CONSTTIME);
		if (!BN_mod(r1,c,rsa->p,ctx)) goto err;
		}
	else
		{
		if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
		}

	/* compute r1^dmp1 mod p */
	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
		{
		dmp1 = &local_dmp1;
		BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
		}
	else
		dmp1 = rsa->dmp1;
	if (!rsa->meth->bn_mod_exp(r0,r1,dmp1,rsa->p,ctx,
		rsa->_method_mod_p)) goto err;

	if (!BN_sub(r0,r0,m1)) goto err;
	/* This will help stop the size of r0 increasing, which does
	 * affect the multiply if it optimised for a power of 2 size */
	if (BN_is_negative(r0))
		if (!BN_add(r0,r0,rsa->p)) goto err;

	if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;

	/* Turn BN_FLG_CONSTTIME flag on before division operation */
	if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
		{
		pr1 = &local_r1;
		BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
		}
	else
		pr1 = r1;
	if (!BN_mod(r0,pr1,rsa->p,ctx)) goto err;

	/* If p < q it is occasionally possible for the correction of
         * adding 'p' if r0 is negative above to leave the result still
	 * negative. This can break the private key operations: the following
	 * second correction should *always* correct this rare occurrence.
	 * This will *never* happen with OpenSSL generated keys because
         * they ensure p > q [steve]
         */
	if (BN_is_negative(r0))
		if (!BN_add(r0,r0,rsa->p)) goto err;
	if (!BN_mul(r1,r0,rsa->q,ctx)) goto err;
	if (!BN_add(r0,r1,m1)) goto err;

	if (rsa->e && rsa->n)
		{
		if (!rsa->meth->bn_mod_exp(vrfy,r0,rsa->e,rsa->n,ctx,rsa->_method_mod_n)) goto err;
		/* If 'I' was greater than (or equal to) rsa->n, the operation
		 * will be equivalent to using 'I mod n'. However, the result of
		 * the verify will *always* be less than 'n' so we don't check
		 * for absolute equality, just congruency. */
		if (!BN_sub(vrfy, vrfy, I)) goto err;
		if (!BN_mod(vrfy, vrfy, rsa->n, ctx)) goto err;
		if (BN_is_negative(vrfy))
			if (!BN_add(vrfy, vrfy, rsa->n)) goto err;
		if (!BN_is_zero(vrfy))
			{
			/* 'I' and 'vrfy' aren't congruent mod n. Don't leak
			 * miscalculated CRT output, just do a raw (slower)
			 * mod_exp and return that instead. */

			BIGNUM local_d;
			BIGNUM *d = NULL;
		
			if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
				{
				d = &local_d;
				BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
				}
			else
				d = rsa->d;
			if (!rsa->meth->bn_mod_exp(r0,I,d,rsa->n,ctx,
						   rsa->_method_mod_n)) goto err;
			}
		}
	ret=1;
err:
	BN_CTX_end(ctx);
	return(ret);
	}

static int RSA_eay_init(RSA *rsa)
	{
	rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
	return(1);
	}

static int RSA_eay_finish(RSA *rsa)
	{
	if (rsa->_method_mod_n != NULL)
		BN_MONT_CTX_free(rsa->_method_mod_n);
	if (rsa->_method_mod_p != NULL)
		BN_MONT_CTX_free(rsa->_method_mod_p);
	if (rsa->_method_mod_q != NULL)
		BN_MONT_CTX_free(rsa->_method_mod_q);
	return(1);
	}

#endif