Add secure DSA nonce flag.

This change adds the option to calculate (EC)DSA nonces by hashing the
message and private key along with entropy to avoid leaking the private
key if the PRNG fails.

1 files changed, 27 insertions, 10 deletions

diff --git a/crypto/ecdsa/ecs_ossl.c b/crypto/ecdsa/ecs_ossl.c
index 8336bceb67..113e60c4b9 100644
--- a/crypto/ecdsa/ecs_ossl.c
+++ b/crypto/ecdsa/ecs_ossl.c
@@ -62,11 +62,13 @@
 #include <openssl/err.h>
 #include <openssl/obj_mac.h>
 #include <openssl/bn.h>
+#include <openssl/rand.h>
 
 static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen, 
 		const BIGNUM *, const BIGNUM *, EC_KEY *eckey);
-static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp, 
-		BIGNUM **rp);
+static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
+			    BIGNUM **kinvp, BIGNUM **rp,
+			    const unsigned char *dgst, int dlen);
 static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len, 
 		const ECDSA_SIG *sig, EC_KEY *eckey);
 
@@ -88,8 +90,9 @@ const ECDSA_METHOD *ECDSA_OpenSSL(void)
 	return &openssl_ecdsa_meth;
 }
 
-static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
-		BIGNUM **rp)
+static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
+			    BIGNUM **kinvp, BIGNUM **rp,
+			    const unsigned char *dgst, int dlen)
 {
 	BN_CTX   *ctx = NULL;
 	BIGNUM	 *k = NULL, *r = NULL, *order = NULL, *X = NULL;
@@ -143,11 +146,26 @@ static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
 	{
 		/* get random k */	
 		do
-			if (!BN_rand_range(k, order))
+#ifndef OPENSSL_NO_SHA512
+			if (EC_KEY_get_nonce_from_hash(eckey))
 			{
-				ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
-				 ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);	
-				goto err;
+				if (!BN_generate_dsa_nonce(k, order, EC_KEY_get0_private_key(eckey),
+							   dgst, dlen, ctx))
+					{
+					ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
+						 ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
+					goto err;
+					}
+			}
+			else
+#endif
+			{
+				if (!BN_rand_range(k, order))
+				{
+					ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
+						 ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
+					goto err;
+				}
 			}
 		while (BN_is_zero(k));
 
@@ -302,8 +320,7 @@ static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
 	{
 		if (in_kinv == NULL || in_r == NULL)
 		{
-			if (!ecdsa->meth->ecdsa_sign_setup(eckey, ctx,
-								&kinv, &ret->r))
+			if (!ecdsa->meth->ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len))
 			{
 				ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,ERR_R_ECDSA_LIB);
 				goto err;