From: Dr. Stephen Henson <steve@openssl.org>
Date: Fri, 22 Apr 2005 13:17:49 +0000 (+0000)
Subject: New function BN_MONT_CTX_set_locked, to set montgomery parameters in a
X-Git-Tag: BEN_FIPS_TEST_8~65
X-Git-Url: https://git.librecmc.org/?a=commitdiff_plain;h=4ed56cba63cc1bcaf0d8ecf1d421b1d6d5b8a159;p=oweals%2Fopenssl.git

New function BN_MONT_CTX_set_locked, to set montgomery parameters in a
threadsafe manner.

Modify or add calls to use it in rsa, dsa and dh algorithms.
---

diff --git a/CHANGES b/CHANGES
index 5644f50166..1a8cc26ada 100644
--- a/CHANGES
+++ b/CHANGES
@@ -4,6 +4,11 @@
 
  Changes between 0.9.7g and 0.9.7h  [XX xxx XXXX]
 
+  *) New function BN_MONT_CTX_set_locked() to set montgomery parameters in
+     a threadsafe manner. Modify rsa code to use new function and add calls
+     to dsa and dh code (which had race conditions before).
+     [Steve Henson]
+
   *) Include the fixed error library code in the C error file definitions
      instead of fixing them up at runtime. This keeps the error code
      structures constant.
diff --git a/crypto/bn/bn.h b/crypto/bn/bn.h
index 3da6d8ced9..ad42f2df7b 100644
--- a/crypto/bn/bn.h
+++ b/crypto/bn/bn.h
@@ -434,6 +434,8 @@ int BN_from_montgomery(BIGNUM *r,const BIGNUM *a,
 void BN_MONT_CTX_free(BN_MONT_CTX *mont);
 int BN_MONT_CTX_set(BN_MONT_CTX *mont,const BIGNUM *mod,BN_CTX *ctx);
 BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to,BN_MONT_CTX *from);
+BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock,
+					const BIGNUM *mod, BN_CTX *ctx);
 
 BN_BLINDING *BN_BLINDING_new(BIGNUM *A,BIGNUM *Ai,BIGNUM *mod);
 void BN_BLINDING_free(BN_BLINDING *b);
diff --git a/crypto/bn/bn_mont.c b/crypto/bn/bn_mont.c
index b79b1b60da..3572e5a690 100644
--- a/crypto/bn/bn_mont.c
+++ b/crypto/bn/bn_mont.c
@@ -347,3 +347,23 @@ BN_MONT_CTX *BN_MONT_CTX_copy(BN_MONT_CTX *to, BN_MONT_CTX *from)
 	return(to);
 	}
 
+BN_MONT_CTX *BN_MONT_CTX_set_locked(BN_MONT_CTX **pmont, int lock,
+					const BIGNUM *mod, BN_CTX *ctx)
+	{
+	if (*pmont)
+		return *pmont;
+	CRYPTO_w_lock(lock);
+	if (!*pmont)
+		{
+		*pmont = BN_MONT_CTX_new();
+		if (*pmont && !BN_MONT_CTX_set(*pmont, mod, ctx))
+			{
+			BN_MONT_CTX_free(*pmont);
+			*pmont = NULL;
+			}
+		}
+	CRYPTO_w_unlock(lock);
+	return *pmont;
+	}
+		
+
diff --git a/crypto/dh/dh_key.c b/crypto/dh/dh_key.c
index ff125c2296..4254176ee2 100644
--- a/crypto/dh/dh_key.c
+++ b/crypto/dh/dh_key.c
@@ -128,13 +128,15 @@ static int generate_key(DH *dh)
 	else
 		pub_key=dh->pub_key;
 
-	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
+
+	if (dh->flags & DH_FLAG_CACHE_MONT_P)
 		{
-		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-				dh->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+				(BN_MONT_CTX **)&dh->method_mont_p,
+				CRYPTO_LOCK_DH, dh->p, ctx);
+		if (!mont)
+			goto err;
 		}
-	mont=(BN_MONT_CTX *)dh->method_mont_p;
 
 	if (generate_new_key)
 		{
@@ -174,14 +176,16 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 		DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
 		goto err;
 		}
-	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
+
+	if (dh->flags & DH_FLAG_CACHE_MONT_P)
 		{
-		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-				dh->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+				(BN_MONT_CTX **)&dh->method_mont_p,
+				CRYPTO_LOCK_DH, dh->p, ctx);
+		if (!mont)
+			goto err;
 		}
 
-	mont=(BN_MONT_CTX *)dh->method_mont_p;
 	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
 		{
 		DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
diff --git a/crypto/dsa/dsa_ossl.c b/crypto/dsa/dsa_ossl.c
index f1a85afcde..2bf83ca419 100644
--- a/crypto/dsa/dsa_ossl.c
+++ b/crypto/dsa/dsa_ossl.c
@@ -198,11 +198,12 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
 		if (!BN_rand_range(&k, dsa->q)) goto err;
 	while (BN_is_zero(&k));
 
-	if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
+	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
 		{
-		if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
-				dsa->p,ctx)) goto err;
+		if (!BN_MONT_CTX_set_locked((BN_MONT_CTX **)&dsa->method_mont_p,
+						CRYPTO_LOCK_DSA,
+						dsa->p, ctx))
+			goto err;
 		}
 
 	/* Compute r = (g^k mod p) mod q */
@@ -275,13 +276,15 @@ static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig,
 	/* u2 = r * w mod q */
 	if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err;
 
-	if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
+
+	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
 		{
-		if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
-				dsa->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+					(BN_MONT_CTX **)&dsa->method_mont_p,
+					CRYPTO_LOCK_DSA, dsa->p, ctx));
+		if (!mont)
+			goto err;
 		}
-	mont=(BN_MONT_CTX *)dsa->method_mont_p;
 
 #if 0
 	{
diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index d4caab3f95..143a25d2c4 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -145,30 +145,13 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
+	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n,
+					CRYPTO_LOCK_RSA, rsa->n, ctx)
 			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 (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 		rsa->_method_mod_n)) goto err;
 
@@ -534,30 +517,14 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		}
 
 	/* do the decrypt */
-	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
+
+	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n,
+					CRYPTO_LOCK_RSA, rsa->n, ctx)
 			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 (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 		rsa->_method_mod_n)) goto err;
 
@@ -604,55 +571,14 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 
 	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);
-			}
-
-		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_MONT_CTX_set_locked(&rsa->_method_mod_p,
+					CRYPTO_LOCK_RSA, rsa->p, ctx)
+			goto err;
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q,
+					CRYPTO_LOCK_RSA, 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,
 		rsa->_method_mod_q)) goto err;
diff --git a/fips/dh/fips_dh_key.c b/fips/dh/fips_dh_key.c
index 4d26bb1619..d037b1e264 100644
--- a/fips/dh/fips_dh_key.c
+++ b/fips/dh/fips_dh_key.c
@@ -131,13 +131,14 @@ static int generate_key(DH *dh)
 	else
 		pub_key=dh->pub_key;
 
-	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
+	if (dh->flags & DH_FLAG_CACHE_MONT_P)
 		{
-		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-				dh->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+				(BN_MONT_CTX **)&dh->method_mont_p,
+				CRYPTO_LOCK_DH, dh->p, ctx);
+		if (!mont)
+			goto err;
 		}
-	mont=(BN_MONT_CTX *)dh->method_mont_p;
 
 	if (generate_new_key)
 		{
@@ -177,14 +178,16 @@ static int compute_key(unsigned char *key, const BIGNUM *pub_key, DH *dh)
 		DHerr(DH_F_DH_COMPUTE_KEY,DH_R_NO_PRIVATE_VALUE);
 		goto err;
 		}
-	if ((dh->method_mont_p == NULL) && (dh->flags & DH_FLAG_CACHE_MONT_P))
+
+	if (dh->flags & DH_FLAG_CACHE_MONT_P)
 		{
-		if ((dh->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dh->method_mont_p,
-				dh->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+				(BN_MONT_CTX **)&dh->method_mont_p,
+				CRYPTO_LOCK_DH, dh->p, ctx);
+		if (!mont)
+			goto err;
 		}
 
-	mont=(BN_MONT_CTX *)dh->method_mont_p;
 	if (!dh->meth->bn_mod_exp(dh, tmp, pub_key, dh->priv_key,dh->p,ctx,mont))
 		{
 		DHerr(DH_F_DH_COMPUTE_KEY,ERR_R_BN_LIB);
diff --git a/fips/dsa/fips_dsa_ossl.c b/fips/dsa/fips_dsa_ossl.c
index 2ed64c483e..fff3b8c4b7 100644
--- a/fips/dsa/fips_dsa_ossl.c
+++ b/fips/dsa/fips_dsa_ossl.c
@@ -223,11 +223,12 @@ static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp)
 		if (!BN_rand_range(&k, dsa->q)) goto err;
 	while (BN_is_zero(&k));
 
-	if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
+	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
 		{
-		if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
-				dsa->p,ctx)) goto err;
+		if (!BN_MONT_CTX_set_locked((BN_MONT_CTX **)&dsa->method_mont_p,
+						CRYPTO_LOCK_DSA,
+						dsa->p, ctx))
+			goto err;
 		}
 
 	/* Compute r = (g^k mod p) mod q */
@@ -307,13 +308,15 @@ static int dsa_do_verify(const unsigned char *dgst, FIPS_DSA_SIZE_T dgst_len, DS
 	/* u2 = r * w mod q */
 	if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err;
 
-	if ((dsa->method_mont_p == NULL) && (dsa->flags & DSA_FLAG_CACHE_MONT_P))
+
+	if (dsa->flags & DSA_FLAG_CACHE_MONT_P)
 		{
-		if ((dsa->method_mont_p=(char *)BN_MONT_CTX_new()) != NULL)
-			if (!BN_MONT_CTX_set((BN_MONT_CTX *)dsa->method_mont_p,
-				dsa->p,ctx)) goto err;
+		mont = BN_MONT_CTX_set_locked(
+					(BN_MONT_CTX **)&dsa->method_mont_p,
+					CRYPTO_LOCK_DSA, dsa->p, ctx);
+		if (!mont)
+			goto err;
 		}
-	mont=(BN_MONT_CTX *)dsa->method_mont_p;
 
 #if 0
 	{
diff --git a/fips/fipshashes.c b/fips/fipshashes.c
index 816694480c..fa51f31854 100644
--- a/fips/fipshashes.c
+++ b/fips/fipshashes.c
@@ -14,13 +14,13 @@ const char * const FIPS_source_hashes[] = {
 "HMAC-SHA1(des/fips_des_locl.h)= e008da40dc6913e374edd66a20d44e1752f00583",
 "HMAC-SHA1(dh/fips_dh_check.c)= 63347e2007e224381d4a7b6d871633889de72cf3",
 "HMAC-SHA1(dh/fips_dh_gen.c)= 93fe69b758ca9d70d70cda1c57fff4eb5c668e85",
-"HMAC-SHA1(dh/fips_dh_key.c)= a84970913f0eaa098fc4e48d4487b45ebe27bcc3",
-"HMAC-SHA1(dsa/fips_dsa_ossl.c)= e02fac446e5f89d22ffa0468fbc97d8dab7a5da8",
+"HMAC-SHA1(dh/fips_dh_key.c)= 90bdc0c2c55aea2feecd16bf9b4bc3717d4c32f4",
+"HMAC-SHA1(dsa/fips_dsa_ossl.c)= 0ff7c3aa1cb111f14ff253870fc2eddfd2224d06",
 "HMAC-SHA1(dsa/fips_dsa_gen.c)= c252db14699f3ff641db052311da7d7521569c53",
 "HMAC-SHA1(dsa/fips_dsa_selftest.c)= 7c2ba8d82feda2aadc8b769a3b6c4c25a6356e01",
 "HMAC-SHA1(rand/fips_rand.c)= 29139e29f56f3ecd99f527af8742d5afb12f409a",
 "HMAC-SHA1(rand/fips_rand.h)= bf009ea8963e79b1e414442ede9ae7010a03160b",
-"HMAC-SHA1(rsa/fips_rsa_eay.c)= dc0c262df0a218b290192edb21639ced4532e857",
+"HMAC-SHA1(rsa/fips_rsa_eay.c)= 2596773a7af8f037427217b79f56858296961d66",
 "HMAC-SHA1(rsa/fips_rsa_gen.c)= 713d2e0d7a1a682b1794f1224b7afe01272ba755",
 "HMAC-SHA1(rsa/fips_rsa_selftest.c)= 8c915b5a4e354dcede93ba08c42858d4dd884e67",
 "HMAC-SHA1(sha1/fips_sha1dgst.c)= 867e990149be16fe9e758b916b5ffc9d9fa61afb",
diff --git a/fips/rsa/fips_rsa_eay.c b/fips/rsa/fips_rsa_eay.c
index 7aa7e8ad41..7613042ed8 100644
--- a/fips/rsa/fips_rsa_eay.c
+++ b/fips/rsa/fips_rsa_eay.c
@@ -153,30 +153,13 @@ static int RSA_eay_public_encrypt(FIPS_RSA_SIZE_T flen, const unsigned char *fro
 		goto err;
 		}
 
-	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
+	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n,
+					CRYPTO_LOCK_RSA, rsa->n, ctx))
 			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 (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 		rsa->_method_mod_n)) goto err;
 
@@ -542,30 +525,14 @@ static int RSA_eay_public_decrypt(FIPS_RSA_SIZE_T flen, const unsigned char *fro
 		}
 
 	/* do the decrypt */
-	if ((rsa->_method_mod_n == NULL) && (rsa->flags & RSA_FLAG_CACHE_PUBLIC))
+
+	if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
 		{
-		BN_MONT_CTX* bn_mont_ctx;
-		if ((bn_mont_ctx=BN_MONT_CTX_new()) == NULL)
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_n,
+					CRYPTO_LOCK_RSA, rsa->n, ctx))
 			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 (!rsa->meth->bn_mod_exp(&ret,&f,rsa->e,rsa->n,ctx,
 		rsa->_method_mod_n)) goto err;
 
@@ -610,57 +577,17 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 	BN_init(&vrfy);
 	if ((ctx=BN_CTX_new()) == NULL) goto err;
 
+
 	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);
-			}
-
-		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_MONT_CTX_set_locked(&rsa->_method_mod_p,
+					CRYPTO_LOCK_RSA, rsa->p, ctx))
+			goto err;
+		if (!BN_MONT_CTX_set_locked(&rsa->_method_mod_q,
+					CRYPTO_LOCK_RSA, 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,
 		rsa->_method_mod_q)) goto err;