1 files changed, 370 insertions, 160 deletions

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index b66b4bc140..c5eaeeae6b 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -55,6 +55,59 @@
  * 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"
@@ -97,43 +150,6 @@ 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), \
-				(rsa)->m, (ctx))) \
-		err_instr
-
 static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
@@ -142,6 +158,28 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	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_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
+		return -1;
+		}
+
+	if (BN_ucmp(rsa->n, rsa->e) <= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT, 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_ENCRYPT, RSA_R_BAD_E_VALUE);
+			return -1;
+			}
+		}
+	
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
 	BN_CTX_start(ctx);
 	f = BN_CTX_get(ctx);
@@ -179,13 +217,15 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	if (BN_bin2bn(buf,num,f) == NULL) goto err;
 	
 	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);
 		goto err;
 		}
 
-	MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, 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;
@@ -212,64 +252,103 @@ err:
 	return(r);
 	}
 
-static int rsa_eay_blinding(RSA *rsa, BN_CTX *ctx)
-	{
-	int ret = 1;
-	CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-	/* Check again inside the lock - the macro's check is racey */
-	if(rsa->blinding == NULL)
-		ret = RSA_blinding_on(rsa, ctx);
-	CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-	return ret;
-	}
+static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
+{
+	BN_BLINDING *ret;
+	int got_write_lock = 0;
+	CRYPTO_THREADID cur;
 
-#define BLINDING_HELPER(rsa, ctx, err_instr) \
-	do { \
-		if((!((rsa)->flags & RSA_FLAG_NO_BLINDING)) && \
-		    ((rsa)->blinding == NULL) && \
-		    !rsa_eay_blinding(rsa, ctx)) \
-			err_instr \
-	} while(0)
+	CRYPTO_r_lock(CRYPTO_LOCK_RSA);
 
-static BN_BLINDING *setup_blinding(RSA *rsa, BN_CTX *ctx)
-	{
-	BIGNUM *A, *Ai;
-	BN_BLINDING *ret = NULL;
+	if (rsa->blinding == NULL)
+		{
+		CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+		CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+		got_write_lock = 1;
 
-	/* added in OpenSSL 0.9.6j and 0.9.7b */
+		if (rsa->blinding == NULL)
+			rsa->blinding = RSA_setup_blinding(rsa, ctx);
+		}
 
-	/* NB: similar code appears in RSA_blinding_on (rsa_lib.c);
-	 * this should be placed in a new function of its own, but for reasons
-	 * of binary compatibility can't */
+	ret = rsa->blinding;
+	if (ret == NULL)
+		goto err;
 
-	BN_CTX_start(ctx);
-	A = BN_CTX_get(ctx);
-	if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
+	CRYPTO_THREADID_current(&cur);
+	if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret)))
 		{
-		/* if PRNG is not properly seeded, resort to secret exponent as unpredictable seed */
-		RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
-		if (!BN_pseudo_rand_range(A,rsa->n)) goto err;
+		/* rsa->blinding is ours! */
+
+		*local = 1;
 		}
 	else
 		{
-		if (!BN_rand_range(A,rsa->n)) goto err;
+		/* 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;
 		}
-	if ((Ai=BN_mod_inverse(NULL,A,rsa->n,ctx)) == NULL) goto err;
 
-	if (!rsa->meth->bn_mod_exp(A,A,rsa->e,rsa->n,ctx,rsa->_method_mod_n))
-		goto err;
-	ret = BN_BLINDING_new(A,Ai,rsa->n);
-	BN_free(Ai);
-err:
-	BN_CTX_end(ctx);
+ 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;
@@ -278,9 +357,10 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
 	BN_CTX_start(ctx);
-	f = BN_CTX_get(ctx);
+	f   = BN_CTX_get(ctx);
+	br  = BN_CTX_get(ctx);
 	ret = BN_CTX_get(ctx);
-	num=BN_num_bytes(rsa->n);
+	num = BN_num_bytes(rsa->n);
 	buf = OPENSSL_malloc(num);
 	if(!f || !ret || !buf)
 		{
@@ -293,6 +373,9 @@ 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;
@@ -312,17 +395,9 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	BLINDING_HELPER(rsa, ctx, goto err;);
-	blinding = rsa->blinding;
-	
-	/* Now unless blinding is disabled, 'blinding' is non-NULL.
-	 * But the BN_BLINDING object may be owned by some other thread
-	 * (we don't want to keep it constant and we don't want to use
-	 * lots of locking to avoid race conditions, so only a single
-	 * thread can use it; other threads have to use local blinding
-	 * factors) */
 	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);
@@ -331,20 +406,8 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		}
 	
 	if (blinding != NULL)
-		{
-		if (blinding->thread_id != CRYPTO_thread_id())
-			{
-			/* we need a local one-time blinding factor */
-
-			blinding = setup_blinding(rsa, ctx);
-			if (blinding == NULL)
-				goto err;
-			local_blinding = 1;
-			}
-		}
-
-	if (blinding)
-		if (!BN_BLINDING_convert(f, blinding, ctx)) goto err;
+		if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
+			goto err;
 
 	if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
 		((rsa->p != NULL) &&
@@ -352,21 +415,50 @@ 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,ctx)) goto err; }
+		{ 
+		if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
+		}
 	else
 		{
-		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,
+		BIGNUM local_d;
+		BIGNUM *d = NULL;
+		
+		if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME))
+			{
+			BN_init(&local_d);
+			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 (!BN_BLINDING_invert(ret, blinding, ctx)) goto err;
+		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;
 
@@ -377,8 +469,6 @@ err:
 		BN_CTX_end(ctx);
 		BN_CTX_free(ctx);
 		}
-	if (local_blinding)
-		BN_BLINDING_free(blinding);
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -390,7 +480,7 @@ 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;
@@ -400,9 +490,10 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 
 	if((ctx = BN_CTX_new()) == NULL) goto err;
 	BN_CTX_start(ctx);
-	f = BN_CTX_get(ctx);
+	f   = BN_CTX_get(ctx);
+	br  = BN_CTX_get(ctx);
 	ret = BN_CTX_get(ctx);
-	num=BN_num_bytes(rsa->n);
+	num = BN_num_bytes(rsa->n);
 	buf = OPENSSL_malloc(num);
 	if(!f || !ret || !buf)
 		{
@@ -427,17 +518,9 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	BLINDING_HELPER(rsa, ctx, goto err;);
-	blinding = rsa->blinding;
-	
-	/* Now unless blinding is disabled, 'blinding' is non-NULL.
-	 * But the BN_BLINDING object may be owned by some other thread
-	 * (we don't want to keep it constant and we don't want to use
-	 * lots of locking to avoid race conditions, so only a single
-	 * thread can use it; other threads have to use local blinding
-	 * factors) */
 	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);
@@ -446,20 +529,8 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		}
 	
 	if (blinding != NULL)
-		{
-		if (blinding->thread_id != CRYPTO_thread_id())
-			{
-			/* we need a local one-time blinding factor */
-
-			blinding = setup_blinding(rsa, ctx);
-			if (blinding == NULL)
-				goto err;
-			local_blinding = 1;
-			}
-		}
-
-	if (blinding)
-		if (!BN_BLINDING_convert(f, blinding, ctx)) goto err;
+		if (!rsa_blinding_convert(blinding, local_blinding, f, br, ctx))
+			goto err;
 
 	/* do the decrypt */
 	if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
@@ -468,17 +539,33 @@ 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,ctx)) goto err; }
+		{
+		if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
+		}
 	else
 		{
-		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,
+		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;
+		  goto err;
 		}
 
 	if (blinding)
-		if (!BN_BLINDING_invert(ret, blinding, ctx)) goto err;
+		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 */
@@ -512,8 +599,6 @@ err:
 		BN_CTX_end(ctx);
 		BN_CTX_free(ctx);
 		}
-	if (local_blinding)
-		BN_BLINDING_free(blinding);
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -532,6 +617,28 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 	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);
@@ -560,11 +667,16 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, 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);
 
@@ -573,6 +685,9 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 	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;
@@ -600,6 +715,8 @@ err:
 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);
@@ -607,26 +724,106 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *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);
+	{
+		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;
+		}
 
-	if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
-	if (!rsa->meth->bn_mod_exp(m1,r1,rsa->dmq1,rsa->q,ctx,
+	/* 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;
 
-	if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
-	if (!rsa->meth->bn_mod_exp(r0,r1,rsa->dmp1,rsa->p,ctx,
+	/* 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_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;
+
+	/* 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
@@ -634,7 +831,7 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 	 * 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;
@@ -648,14 +845,27 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
 		 * 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_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_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: