X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frsa%2Frsa_eay.c;h=69cabd2716445bb1a88b2ef0273b6d498b8ecc41;hp=24c77699fe6ad1603b9086cf37e5dac55381af92;hb=675f605d44630d491f10c846344679e8fc90b119;hpb=b12753dffcf096c7d7110397ea9905b07a2ed573

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 24c77699fe..69cabd2716 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -55,15 +55,65 @@
  * copied and put under another distribution licence
  * [including the GNU Public Licence.]
  */
+/* ====================================================================
+ * Copyright (c) 1998-2006 The OpenSSL Project.  All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@openssl.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
 
 #include <stdio.h>
 #include "cryptlib.h"
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
 #include <openssl/rand.h>
-#ifndef OPENSSL_NO_ENGINE
-#include <openssl/engine.h>
-#endif
 
 #ifndef RSA_NULL
 
@@ -75,7 +125,7 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		unsigned char *to, RSA *rsa,int padding);
 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		unsigned char *to, RSA *rsa,int padding);
-static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa);
+static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx);
 static int RSA_eay_init(RSA *rsa);
 static int RSA_eay_finish(RSA *rsa);
 static RSA_METHOD rsa_pkcs1_eay_meth={
@@ -100,56 +150,31 @@ const RSA_METHOD *RSA_PKCS1_SSLeay(void)
 	return(&rsa_pkcs1_eay_meth);
 	}
 
-/* Static helper to reduce oodles of code duplication. As a slight
- * optimisation, the "MONT_HELPER() macro must be used as front-end to this
- * function, to prevent unnecessary function calls - there is an initial test
- * that is performed by the macro-generated code. */
-static int rsa_eay_mont_helper(BN_MONT_CTX **ptr, const BIGNUM *modulus, BN_CTX *ctx)
-	{
-	BN_MONT_CTX *bn_mont_ctx;
-	if((bn_mont_ctx = BN_MONT_CTX_new()) == NULL)
-		return 0;
-	if(!BN_MONT_CTX_set(bn_mont_ctx, modulus, ctx))
-		{
-		BN_MONT_CTX_free(bn_mont_ctx);
-		return 0;
-		}
-	if (*ptr == NULL) /* other thread may have finished first */
-		{
-		CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-		if (*ptr == NULL) /* check again in the lock to stop races */
-			{
-			*ptr = bn_mont_ctx;
-			bn_mont_ctx = NULL;
-			}
-		CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-		}
-	if (bn_mont_ctx)
-		BN_MONT_CTX_free(bn_mont_ctx);
-	return 1;
-	}
 /* Usage example;
  *    MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
  */
 #define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
 	if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
-			!rsa_eay_mont_helper(&((rsa)->_method_mod_##m), \
+			!BN_MONT_CTX_set_locked(&((rsa)->_method_mod_##m), \
+				CRYPTO_LOCK_RSA, \
 				(rsa)->m, (ctx))) \
 		err_instr
 
 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	int i,j,k,num=0,r= -1;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
-	BN_init(&f);
-	BN_init(&ret);
 	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);
-	if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
+	buf = OPENSSL_malloc(num);
+	if (!f || !ret || !buf)
 		{
 		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
 		goto err;
@@ -177,9 +202,9 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 		}
 	if (i <= 0) goto err;
 
-	if (BN_bin2bn(buf,num,&f) == NULL) goto err;
+	if (BN_bin2bn(buf,num,f) == NULL) goto err;
 	
-	if (BN_ucmp(&f, rsa->n) >= 0)
+	if (BN_ucmp(f, rsa->n) >= 0)
 		{	
 		/* usually the padding functions would catch this */
 		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
@@ -188,21 +213,23 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 
 	MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
-	if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
+	if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
 		rsa->_method_mod_n)) goto err;
 
 	/* put in leading 0 bytes if the number is less than the
 	 * length of the modulus */
-	j=BN_num_bytes(&ret);
-	i=BN_bn2bin(&ret,&(to[num-j]));
+	j=BN_num_bytes(ret);
+	i=BN_bn2bin(ret,&(to[num-j]));
 	for (k=0; k<(num-i); k++)
 		to[k]=0;
 
 	r=num;
 err:
-	if (ctx != NULL) BN_CTX_free(ctx);
-	BN_clear_free(&f);
-	BN_clear_free(&ret);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
 	if (buf != NULL) 
 		{
 		OPENSSL_cleanse(buf,num);
@@ -211,21 +238,115 @@ err:
 	return(r);
 	}
 
+static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
+{
+	BN_BLINDING *ret;
+	int got_write_lock = 0;
+
+	CRYPTO_r_lock(CRYPTO_LOCK_RSA);
+
+	if (rsa->blinding == NULL)
+		{
+		CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+		CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+		got_write_lock = 1;
+
+		if (rsa->blinding == NULL)
+			rsa->blinding = RSA_setup_blinding(rsa, ctx);
+		}
+
+	ret = rsa->blinding;
+	if (ret == NULL)
+		goto err;
+
+	if (BN_BLINDING_get_thread_id(ret) == CRYPTO_thread_id())
+		{
+		/* rsa->blinding is ours! */
+
+		*local = 1;
+		}
+	else
+		{
+		/* resort to rsa->mt_blinding instead */
+
+		*local = 0; /* instructs rsa_blinding_convert(), rsa_blinding_invert()
+		             * that the BN_BLINDING is shared, meaning that accesses
+		             * require locks, and that the blinding factor must be
+		             * stored outside the BN_BLINDING
+		             */
+
+		if (rsa->mt_blinding == NULL)
+			{
+			if (!got_write_lock)
+				{
+				CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+				CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+				got_write_lock = 1;
+				}
+			
+			if (rsa->mt_blinding == NULL)
+				rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
+			}
+		ret = rsa->mt_blinding;
+		}
+
+ err:
+	if (got_write_lock)
+		CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
+	else
+		CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+	return ret;
+}
+
+static int rsa_blinding_convert(BN_BLINDING *b, int local, BIGNUM *f,
+	BIGNUM *r, BN_CTX *ctx)
+{
+	if (local)
+		return BN_BLINDING_convert_ex(f, NULL, b, ctx);
+	else
+		{
+		int ret;
+		CRYPTO_r_lock(CRYPTO_LOCK_RSA_BLINDING);
+		ret = BN_BLINDING_convert_ex(f, r, b, ctx);
+		CRYPTO_r_unlock(CRYPTO_LOCK_RSA_BLINDING);
+		return ret;
+		}
+}
+
+static int rsa_blinding_invert(BN_BLINDING *b, int local, BIGNUM *f,
+	BIGNUM *r, BN_CTX *ctx)
+{
+	if (local)
+		return BN_BLINDING_invert_ex(f, NULL, b, ctx);
+	else
+		{
+		int ret;
+		CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
+		ret = BN_BLINDING_invert_ex(f, r, b, ctx);
+		CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
+		return ret;
+		}
+}
+
 /* signing */
 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	BIGNUM f,ret;
+	BIGNUM *f, *ret, *br, *res;
 	int i,j,k,num=0,r= -1;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
-
-	BN_init(&f);
-	BN_init(&ret);
+	int local_blinding = 0;
+	BN_BLINDING *blinding = NULL;
 
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
-	num=BN_num_bytes(rsa->n);
-	if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
+	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_ENCRYPT,ERR_R_MALLOC_FAILURE);
 		goto err;
@@ -236,6 +357,9 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 	case RSA_PKCS1_PADDING:
 		i=RSA_padding_add_PKCS1_type_1(buf,num,from,flen);
 		break;
+	case RSA_X931_PADDING:
+		i=RSA_padding_add_X931(buf,num,from,flen);
+		break;
 	case RSA_NO_PADDING:
 		i=RSA_padding_add_none(buf,num,from,flen);
 		break;
@@ -246,19 +370,28 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		}
 	if (i <= 0) goto err;
 
-	if (BN_bin2bn(buf,num,&f) == NULL) goto err;
+	if (BN_bin2bn(buf,num,f) == NULL) goto err;
 	
-	if (BN_ucmp(&f, rsa->n) >= 0)
+	if (BN_ucmp(f, rsa->n) >= 0)
 		{	
 		/* usually the padding functions would catch this */
 		RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 		goto err;
 		}
 
-	if ((rsa->flags & RSA_FLAG_BLINDING) && (rsa->blinding == NULL))
-		RSA_blinding_on(rsa,ctx);
-	if (rsa->flags & RSA_FLAG_BLINDING)
-		if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) 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_ENCRYPT, ERR_R_INTERNAL_ERROR);
+			goto err;
+			}
+		}
+	
+	if (blinding != NULL)
+		if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
+			goto err;
 
 	if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 		((rsa->p != NULL) &&
@@ -266,29 +399,58 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		(rsa->dmp1 != NULL) &&
 		(rsa->dmq1 != NULL) &&
 		(rsa->iqmp != NULL)) )
-		{ if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
+		{ 
+		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_EXP_CONSTTIME))
+			{
+			BN_init(&local_d);
+			d = &local_d;
+			BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+			}
+		else
+			d = rsa->d;
+
 		MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
-		if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,
+
+		if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 				rsa->_method_mod_n)) goto err;
 		}
 
-	if (rsa->flags & RSA_FLAG_BLINDING)
-		if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) goto err;
+	if (blinding)
+		if (!rsa_blinding_invert(blinding, local_blinding, ret, br, ctx))
+			goto err;
+
+	if (padding == RSA_X931_PADDING)
+		{
+		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(&ret);
-	i=BN_bn2bin(&ret,&(to[num-j]));
+	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_free(ctx);
-	BN_clear_free(&ret);
-	BN_clear_free(&f);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -300,20 +462,22 @@ err:
 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	BIGNUM f,ret;
+	BIGNUM *f, *ret, *br;
 	int j,num=0,r= -1;
 	unsigned char *p;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
-
-	BN_init(&f);
-	BN_init(&ret);
-	ctx=BN_CTX_new();
-	if (ctx == NULL) goto err;
-
-	num=BN_num_bytes(rsa->n);
-
-	if ((buf=(unsigned char *)OPENSSL_malloc(num)) == 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;
@@ -328,18 +492,27 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		}
 
 	/* make data into a big number */
-	if (BN_bin2bn(from,(int)flen,&f) == NULL) goto err;
+	if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
 
-	if (BN_ucmp(&f, rsa->n) >= 0)
+	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_BLINDING) && (rsa->blinding == NULL))
-		RSA_blinding_on(rsa,ctx);
-	if (rsa->flags & RSA_FLAG_BLINDING)
-		if (!BN_BLINDING_convert(&f,rsa->blinding,ctx)) 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) ||
@@ -348,20 +521,34 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		(rsa->dmp1 != NULL) &&
 		(rsa->dmq1 != NULL) &&
 		(rsa->iqmp != NULL)) )
-		{ if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
+		{
+		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_EXP_CONSTTIME))
+			{
+			d = &local_d;
+			BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+			}
+		else
+			d = rsa->d;
+
 		MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
-		if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,
+		if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
 				rsa->_method_mod_n))
-			goto err;
+		  goto err;
 		}
 
-	if (rsa->flags & RSA_FLAG_BLINDING)
-		if (!BN_BLINDING_invert(&ret,rsa->blinding,ctx)) 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 */
+	j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
 
 	switch (padding)
 		{
@@ -387,9 +574,11 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 
 err:
-	if (ctx != NULL) BN_CTX_free(ctx);
-	BN_clear_free(&f);
-	BN_clear_free(&ret);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -402,20 +591,19 @@ err:
 static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	int i,num=0,r= -1;
 	unsigned char *p;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
-	BN_init(&f);
-	BN_init(&ret);
-	ctx=BN_CTX_new();
-	if (ctx == NULL) goto err;
-
+	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=(unsigned char *)OPENSSL_malloc(num);
-	if (buf == NULL)
+	buf = OPENSSL_malloc(num);
+	if(!f || !ret || !buf)
 		{
 		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
 		goto err;
@@ -429,9 +617,9 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	if (BN_bin2bn(from,flen,&f) == NULL) goto err;
+	if (BN_bin2bn(from,flen,f) == NULL) goto err;
 
-	if (BN_ucmp(&f, rsa->n) >= 0)
+	if (BN_ucmp(f, rsa->n) >= 0)
 		{
 		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
 		goto err;
@@ -439,17 +627,23 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 
 	MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
-	if (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
+	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);
+	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;
@@ -461,9 +655,11 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
 
 err:
-	if (ctx != NULL) BN_CTX_free(ctx);
-	BN_clear_free(&f);
-	BN_clear_free(&ret);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -472,37 +668,52 @@ err:
 	return(r);
 	}
 
-static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
+static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 	{
-	BIGNUM r1,m1,vrfy;
+	BIGNUM *r1,*m1,*vrfy;
+	BIGNUM local_dmp1, local_dmq1;
+	BIGNUM *dmp1, *dmq1;
 	int ret=0;
-	BN_CTX *ctx;
 
-	BN_init(&m1);
-	BN_init(&r1);
-	BN_init(&vrfy);
-	if ((ctx=BN_CTX_new()) == NULL) goto err;
+	BN_CTX_start(ctx);
+	r1 = BN_CTX_get(ctx);
+	m1 = BN_CTX_get(ctx);
+	vrfy = BN_CTX_get(ctx);
 
 	MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 	MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
 	MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
-	if (!BN_mod(&r1,I,rsa->q,ctx)) goto err;
-	if (!rsa->meth->bn_mod_exp(&m1,&r1,rsa->dmq1,rsa->q,ctx,
+	if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
+	if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+		{
+		dmq1 = &local_dmq1;
+		BN_with_flags(dmq1, rsa->dmq1, BN_FLG_EXP_CONSTTIME);
+		}
+	else
+		dmq1 = rsa->dmq1;
+	if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
 		rsa->_method_mod_q)) goto err;
 
-	if (!BN_mod(&r1,I,rsa->p,ctx)) goto err;
-	if (!rsa->meth->bn_mod_exp(r0,&r1,rsa->dmp1,rsa->p,ctx,
+	if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
+	if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+		{
+		dmp1 = &local_dmp1;
+		BN_with_flags(dmp1, rsa->dmp1, BN_FLG_EXP_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;
+	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_get_sign(r0))
+	if (BN_is_negative(r0))
 		if (!BN_add(r0,r0,rsa->p)) goto err;
 
-	if (!BN_mul(&r1,r0,rsa->iqmp,ctx)) goto err;
-	if (!BN_mod(r0,&r1,rsa->p,ctx)) goto err;
+	if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
+	if (!BN_mod(r0,r1,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
@@ -510,35 +721,45 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 	 * This will *never* happen with OpenSSL generated keys because
          * they ensure p > q [steve]
          */
-	if (BN_get_sign(r0))
+	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 (!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 (!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_get_sign(&vrfy))
-			if (!BN_add(&vrfy, &vrfy, rsa->n)) goto err;
-		if (!BN_is_zero(&vrfy))
+		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. */
-			if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,
-					rsa->_method_mod_n)) goto err;
+
+			BIGNUM local_d;
+			BIGNUM *d = NULL;
+		
+			if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+				{
+				d = &local_d;
+				BN_with_flags(d, rsa->d, BN_FLG_EXP_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_clear_free(&m1);
-	BN_clear_free(&r1);
-	BN_clear_free(&vrfy);
-	BN_CTX_free(ctx);
+	BN_CTX_end(ctx);
 	return(ret);
 	}