X-Git-Url: https://git.openssl.org/gitweb/?p=openssl.git;a=blobdiff_plain;f=crypto%2Frsa%2Frsa_eay.c;h=3ee753ec86d1f3027afcfe0f04ce14fbdf0176b4;hp=6a68770031d6d651b3903d24a8529ce2eda2715e;hb=ff22e913a3fbeb025e612828859102aa1a3effaa;hpb=975842f9fb216e453b67c19ffe4509837fb59ccb

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index 6a68770031..3ee753ec86 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -61,7 +61,6 @@
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
 #include <openssl/rand.h>
-#include <openssl/engine.h>
 
 #ifndef RSA_NULL
 
@@ -73,21 +72,24 @@ 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={
 	"Eric Young's PKCS#1 RSA",
 	RSA_eay_public_encrypt,
-	RSA_eay_public_decrypt,
-	RSA_eay_private_encrypt,
+	RSA_eay_public_decrypt, /* signature verification */
+	RSA_eay_private_encrypt, /* signing */
 	RSA_eay_private_decrypt,
 	RSA_eay_mod_exp,
 	BN_mod_exp_mont, /* XXX probably we should not use Montgomery if  e == 3 */
 	RSA_eay_init,
 	RSA_eay_finish,
-	0,
+	0, /* flags */
 	NULL,
+	0, /* rsa_sign */
+	0, /* rsa_verify */
+	NULL /* rsa_keygen */
 	};
 
 const RSA_METHOD *RSA_PKCS1_SSLeay(void)
@@ -95,21 +97,58 @@ 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)
 	{
-	const RSA_METHOD *meth;
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	int i,j,k,num=0,r= -1;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
-	meth = ENGINE_get_RSA(rsa->engine);
-	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;
@@ -120,7 +159,7 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 	case RSA_PKCS1_PADDING:
 		i=RSA_padding_add_PKCS1_type_2(buf,num,from,flen);
 		break;
-#ifndef NO_SHA
+#ifndef OPENSSL_NO_SHA
 	case RSA_PKCS1_OAEP_PADDING:
 	        i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
 		break;
@@ -137,71 +176,113 @@ 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 ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
-		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
-			goto err;
-		if (!BN_MONT_CTX_set(bn_mont_ctx,rsa->n,ctx))
-			{
-			BN_MONT_CTX_free(bn_mont_ctx);
-			goto err;
-			}
-		if (rsa->_method_mod_n == NULL) /* other thread may have finished first */
-			{
-			CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-			if (rsa->_method_mod_n == NULL)
-				{
-				rsa->_method_mod_n = bn_mont_ctx;
-				bn_mont_ctx = NULL;
-				}
-			CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-			}
-		if (bn_mont_ctx)
-			BN_MONT_CTX_free(bn_mont_ctx);
+	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;
 		}
-		
-	if (!meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
+
+	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,
 		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) 
 		{
-		memset(buf,0,num);
+		OPENSSL_cleanse(buf,num);
 		OPENSSL_free(buf);
 		}
 	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;
+	}
+
+#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)
+
+static BN_BLINDING *setup_blinding(RSA *rsa, BN_CTX *ctx)
+	{
+	BIGNUM *A, *Ai;
+	BN_BLINDING *ret = NULL;
+
+	/* added in OpenSSL 0.9.6j and 0.9.7b */
+
+	/* 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 */
+
+	BN_CTX_start(ctx);
+	A = BN_CTX_get(ctx);
+	if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
+		{
+		/* 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;
+		}
+	else
+		{
+		if (!BN_rand_range(A,rsa->n)) goto err;
+		}
+	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);
+	return ret;
+	}
+
+/* signing */
 static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	const RSA_METHOD *meth;
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	int i,j,k,num=0,r= -1;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
-
-	meth = ENGINE_get_RSA(rsa->engine);
-	BN_init(&f);
-	BN_init(&ret);
+	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);
+	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_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
 		goto err;
@@ -222,12 +303,48 @@ 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)
+		{	
+		/* 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;
+	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))
+		{
+		if (blinding == NULL)
+			{
+			RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
+			goto err;
+			}
+		}
+	
+	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->flags & RSA_FLAG_EXT_PKEY) ||
 		((rsa->p != NULL) &&
@@ -235,30 +352,36 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		(rsa->dmp1 != NULL) &&
 		(rsa->dmq1 != NULL) &&
 		(rsa->iqmp != NULL)) )
-		{ if (!meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
+		{ if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
 	else
 		{
-		if (!meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,NULL)) goto err;
+		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,
+				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 (!BN_BLINDING_invert(ret, blinding, ctx)) 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(&ret);
-	BN_clear_free(&f);
+	if (ctx != NULL)
+		{
+		BN_CTX_end(ctx);
+		BN_CTX_free(ctx);
+		}
+	if (local_blinding)
+		BN_BLINDING_free(blinding);
 	if (buf != NULL)
 		{
-		memset(buf,0,num);
+		OPENSSL_cleanse(buf,num);
 		OPENSSL_free(buf);
 		}
 	return(r);
@@ -267,22 +390,21 @@ err:
 static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 	     unsigned char *to, RSA *rsa, int padding)
 	{
-	const RSA_METHOD *meth;
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	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;
 
-	meth = ENGINE_get_RSA(rsa->engine);
-	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);
-
-	if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
+	buf = OPENSSL_malloc(num);
+	if(!f || !ret || !buf)
 		{
 		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
 		goto err;
@@ -297,12 +419,47 @@ 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 ((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 (BN_ucmp(f, rsa->n) >= 0)
+		{
+		RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		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))
+		{
+		if (blinding == NULL)
+			{
+			RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
+			goto err;
+			}
+		}
+	
+	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;
 
 	/* do the decrypt */
 	if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
@@ -311,25 +468,27 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		(rsa->dmp1 != NULL) &&
 		(rsa->dmq1 != NULL) &&
 		(rsa->iqmp != NULL)) )
-		{ if (!meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
+		{ if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
 	else
 		{
-		if (!meth->bn_mod_exp(&ret,&f,rsa->d,rsa->n,ctx,NULL))
+		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,
+				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 (!BN_BLINDING_invert(ret, blinding, 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)
 		{
 	case RSA_PKCS1_PADDING:
 		r=RSA_padding_check_PKCS1_type_2(to,num,buf,j,num);
 		break;
-#ifndef NO_SHA
+#ifndef OPENSSL_NO_SHA
         case RSA_PKCS1_OAEP_PADDING:
 	        r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
                 break;
@@ -348,36 +507,38 @@ 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 (local_blinding)
+		BN_BLINDING_free(blinding);
 	if (buf != NULL)
 		{
-		memset(buf,0,num);
+		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)
 	{
-	const RSA_METHOD *meth;
-	BIGNUM f,ret;
+	BIGNUM *f,*ret;
 	int i,num=0,r= -1;
 	unsigned char *p;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
 
-	meth = ENGINE_get_RSA(rsa->engine);
-	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;
@@ -391,37 +552,21 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	if (BN_bin2bn(from,flen,&f) == NULL) goto err;
-	/* do the decrypt */
-	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
+	if (BN_bin2bn(from,flen,f) == NULL) goto err;
+
+	if (BN_ucmp(f, rsa->n) >= 0)
 		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
-			goto err;
-		if (!BN_MONT_CTX_set(bn_mont_ctx,rsa->n,ctx))
-			{
-			BN_MONT_CTX_free(bn_mont_ctx);
-			goto err;
-			}
-		if (rsa->_method_mod_n == NULL) /* other thread may have finished first */
-			{
-			CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-			if (rsa->_method_mod_n == NULL)
-				{
-				rsa->_method_mod_n = bn_mont_ctx;
-				bn_mont_ctx = NULL;
-				}
-			CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-			}
-		if (bn_mont_ctx)
-			BN_MONT_CTX_free(bn_mont_ctx);
+		RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+		goto err;
 		}
-		
-	if (!meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
+
+	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,
 		rsa->_method_mod_n)) goto err;
 
 	p=buf;
-	i=BN_bn2bin(&ret,p);
+	i=BN_bn2bin(ret,p);
 
 	switch (padding)
 		{
@@ -439,96 +584,49 @@ 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)
 		{
-		memset(buf,0,num);
+		OPENSSL_cleanse(buf,num);
 		OPENSSL_free(buf);
 		}
 	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)
 	{
-	const RSA_METHOD *meth;
-	BIGNUM r1,m1;
+	BIGNUM *r1,*m1,*vrfy;
 	int ret=0;
-	BN_CTX *ctx;
 
-	meth = ENGINE_get_RSA(rsa->engine);
-	if ((ctx=BN_CTX_new()) == NULL) goto err;
-	BN_init(&m1);
-	BN_init(&r1);
+	BN_CTX_start(ctx);
+	r1 = BN_CTX_get(ctx);
+	m1 = BN_CTX_get(ctx);
+	vrfy = BN_CTX_get(ctx);
 
-	if (rsa->flags & RSA_FLAG_CACHE_PRIVATE)
-		{
-		if (rsa->_method_mod_p == NULL)
-			{
-			BN_MONT_CTX* bn_mont_ctx;
-			if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
-				goto err;
-			if (!BN_MONT_CTX_set(bn_mont_ctx,rsa->p,ctx))
-				{
-				BN_MONT_CTX_free(bn_mont_ctx);
-				goto err;
-				}
-			if (rsa->_method_mod_p == NULL) /* other thread may have finished first */
-				{
-				CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-				if (rsa->_method_mod_p == NULL)
-					{
-					rsa->_method_mod_p = bn_mont_ctx;
-					bn_mont_ctx = NULL;
-					}
-				CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-				}
-			if (bn_mont_ctx)
-				BN_MONT_CTX_free(bn_mont_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 (rsa->_method_mod_q == NULL)
-			{
-			BN_MONT_CTX* bn_mont_ctx;
-			if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
-				goto err;
-			if (!BN_MONT_CTX_set(bn_mont_ctx,rsa->q,ctx))
-				{
-				BN_MONT_CTX_free(bn_mont_ctx);
-				goto err;
-				}
-			if (rsa->_method_mod_q == NULL) /* other thread may have finished first */
-				{
-				CRYPTO_w_lock(CRYPTO_LOCK_RSA);
-				if (rsa->_method_mod_q == NULL)
-					{
-					rsa->_method_mod_q = bn_mont_ctx;
-					bn_mont_ctx = NULL;
-					}
-				CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
-				}
-			if (bn_mont_ctx)
-				BN_MONT_CTX_free(bn_mont_ctx);
-			}
-		}
-		
-	if (!BN_mod(&r1,I,rsa->q,ctx)) goto err;
-	if (!meth->bn_mod_exp(&m1,&r1,rsa->dmq1,rsa->q,ctx,
+	if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
+	if (!rsa->meth->bn_mod_exp(m1,r1,rsa->dmq1,rsa->q,ctx,
 		rsa->_method_mod_q)) goto err;
 
-	if (!BN_mod(&r1,I,rsa->p,ctx)) goto err;
-	if (!meth->bn_mod_exp(r0,&r1,rsa->dmp1,rsa->p,ctx,
+	if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
+	if (!rsa->meth->bn_mod_exp(r0,r1,rsa->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 (r0->neg)
+	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
@@ -536,16 +634,32 @@ 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 (r0->neg)
+	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 '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. */
+			if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,
+					rsa->_method_mod_n)) goto err;
+		}
 	ret=1;
 err:
-	BN_clear_free(&m1);
-	BN_clear_free(&r1);
-	BN_CTX_free(ctx);
+	BN_CTX_end(ctx);
 	return(ret);
 	}