1 files changed, 20 insertions, 26 deletions

diff --git a/app/openssl/crypto/bn/bn_mont.c b/app/openssl/crypto/bn/bn_mont.c
index ee8532c7..427b5cf4 100644
--- a/app/openssl/crypto/bn/bn_mont.c
+++ b/app/openssl/crypto/bn/bn_mont.c
@@ -478,38 +478,32 @@ 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)
 	{
+	int got_write_lock = 0;
 	BN_MONT_CTX *ret;
 
 	CRYPTO_r_lock(lock);
-	ret = *pmont;
-	CRYPTO_r_unlock(lock);
-	if (ret)
-		return ret;
-
-	/* We don't want to serialise globally while doing our lazy-init math in
-	 * BN_MONT_CTX_set. That punishes threads that are doing independent
-	 * things. Instead, punish the case where more than one thread tries to
-	 * lazy-init the same 'pmont', by having each do the lazy-init math work
-	 * independently and only use the one from the thread that wins the race
-	 * (the losers throw away the work they've done). */
-	ret = BN_MONT_CTX_new();
-	if (!ret)
-		return NULL;
-	if (!BN_MONT_CTX_set(ret, mod, ctx))
+	if (!*pmont)
 		{
-		BN_MONT_CTX_free(ret);
-		return NULL;
-		}
+		CRYPTO_r_unlock(lock);
+		CRYPTO_w_lock(lock);
+		got_write_lock = 1;
 
-	/* The locked compare-and-set, after the local work is done. */
-	CRYPTO_w_lock(lock);
-	if (*pmont)
-		{
-		BN_MONT_CTX_free(ret);
-		ret = *pmont;
+		if (!*pmont)
+			{
+			ret = BN_MONT_CTX_new();
+			if (ret && !BN_MONT_CTX_set(ret, mod, ctx))
+				BN_MONT_CTX_free(ret);
+			else
+				*pmont = ret;
+			}
 		}
+	
+	ret = *pmont;
+	
+	if (got_write_lock)
+		CRYPTO_w_unlock(lock);
 	else
-		*pmont = ret;
-	CRYPTO_w_unlock(lock);
+		CRYPTO_r_unlock(lock);
+		
 	return ret;
 	}