1 files changed, 184 insertions, 115 deletions

diff --git a/crypto/rsa/rsa_eay.c b/crypto/rsa/rsa_eay.c
index cab34847df..ad6ccf634d 100644
--- a/crypto/rsa/rsa_eay.c
+++ b/crypto/rsa/rsa_eay.c
@@ -61,7 +61,9 @@
 #include <openssl/bn.h>
 #include <openssl/rsa.h>
 #include <openssl/rand.h>
+#ifndef OPENSSL_NO_ENGINE
 #include <openssl/engine.h>
+#endif
 
 #ifndef RSA_NULL
 
@@ -98,6 +100,43 @@ 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)
 	{
@@ -147,30 +186,8 @@ 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))
-		{
-		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);
-		}
-		
+	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;
 
@@ -194,6 +211,59 @@ 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;
+	}
+
+#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);
+		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)
@@ -202,6 +272,8 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 	int i,j,k,num=0,r= -1;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
+	int local_blinding = 0;
+	BN_BLINDING *blinding = NULL;
 
 	BN_init(&f);
 	BN_init(&ret);
@@ -238,10 +310,39 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		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) &&
@@ -252,11 +353,13 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
 		{ if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
 	else
 		{
-		if (!rsa->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 */
@@ -270,6 +373,8 @@ err:
 	if (ctx != NULL) BN_CTX_free(ctx);
 	BN_clear_free(&ret);
 	BN_clear_free(&f);
+	if (local_blinding)
+		BN_BLINDING_free(blinding);
 	if (buf != NULL)
 		{
 		OPENSSL_cleanse(buf,num);
@@ -286,6 +391,8 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 	unsigned char *p;
 	unsigned char *buf=NULL;
 	BN_CTX *ctx=NULL;
+	int local_blinding = 0;
+	BN_BLINDING *blinding = NULL;
 
 	BN_init(&f);
 	BN_init(&ret);
@@ -317,10 +424,39 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		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_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) ||
@@ -332,12 +468,14 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
 		{ if (!rsa->meth->rsa_mod_exp(&ret,&f,rsa)) goto err; }
 	else
 		{
-		if (!rsa->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 */
@@ -416,31 +554,8 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
 		goto err;
 		}
 
-	/* do the decrypt */
-	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);
-		}
-		
+	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;
 
@@ -485,57 +600,10 @@ 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);
-			}
+	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 (!rsa->meth->bn_mod_exp(&m1,&r1,rsa->dmq1,rsa->q,ctx,
 		rsa->_method_mod_q)) goto err;
@@ -566,7 +634,7 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 
 	if (rsa->e && rsa->n)
 		{
-		if (!rsa->meth->bn_mod_exp(&vrfy,r0,rsa->e,rsa->n,ctx,NULL)) 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
@@ -579,7 +647,8 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
 			/* '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,NULL)) goto err;
+			if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,
+					rsa->_method_mod_n)) goto err;
 		}
 	ret=1;
 err: