x509: store and read provable seed in PKCS#8 form of key

Signed-off-by: Nikos Mavrogiannopoulos <nmav@redhat.com>

6 files changed, 201 insertions, 10 deletions

diff --git a/lib/x509/Makefile.am b/lib/x509/Makefile.am
index 2a775eacc7..d4d9cdae61 100644
--- a/lib/x509/Makefile.am
+++ b/lib/x509/Makefile.am
@@ -44,6 +44,8 @@ libgnutls_x509_la_SOURCES =	\
 	dn.c			\
 	attributes.c		\
 	attributes.h		\
+	prov-seed.c		\
+	prov-seed.h		\
 	extensions.c		\
 	mpi.c			\
 	output.c		\
diff --git a/lib/x509/privkey.c b/lib/x509/privkey.c
index 87de8087cc..81ff5c6db3 100644
--- a/lib/x509/privkey.c
+++ b/lib/x509/privkey.c
@@ -250,7 +250,6 @@ _gnutls_privkey_decode_pkcs1_rsa_key(const gnutls_datum_t * raw_key,
 	gnutls_pk_params_clear(&pkey->params);
 	gnutls_pk_params_release(&pkey->params);
 	return NULL;
-
 }
 
 /* Converts an ECC key to
diff --git a/lib/x509/privkey_pkcs8.c b/lib/x509/privkey_pkcs8.c
index dea9a5482c..46351dca25 100644
--- a/lib/x509/privkey_pkcs8.c
+++ b/lib/x509/privkey_pkcs8.c
@@ -37,6 +37,8 @@
 #include <random.h>
 #include <pk.h>
 #include <nettle/pbkdf2.h>
+#include "attributes.h"
+#include "prov-seed.h"
 
 static int _decode_pkcs8_ecc_key(ASN1_TYPE pkcs8_asn,
 				 gnutls_x509_privkey_t pkey);
@@ -217,13 +219,30 @@ encode_to_private_key_info(gnutls_x509_privkey_t pkey,
 		goto error;
 	}
 
-	/* Append an empty Attributes field.
-	 */
-	result = asn1_write_value(*pkey_info, "attributes", NULL, 0);
-	if (result != ASN1_SUCCESS) {
-		gnutls_assert();
-		result = _gnutls_asn2err(result);
-		goto error;
+	if ((pkey->params.flags & GNUTLS_PK_FLAG_PROVABLE) && pkey->params.seed_size > 0) {
+		gnutls_datum_t seed_info;
+
+		result = _x509_encode_provable_seed(pkey, &seed_info);
+		if (result < 0) {
+			gnutls_assert();
+			goto error;
+		}
+
+		result = _x509_set_attribute(*pkey_info, "attributes", OID_ATTR_PROV_SEED, &seed_info);
+		gnutls_free(seed_info.data);
+		if (result < 0) {
+			gnutls_assert();
+			goto error;
+		}
+	} else {
+		/* Append an empty Attributes field.
+		 */
+		result = asn1_write_value(*pkey_info, "attributes", NULL, 0);
+		if (result != ASN1_SUCCESS) {
+			gnutls_assert();
+			result = _gnutls_asn2err(result);
+			goto error;
+		}
 	}
 
 	/* DER Encode the generated private key info.
@@ -1173,6 +1192,8 @@ decode_private_key_info(const gnutls_datum_t * der,
 	int result, len;
 	char oid[MAX_OID_SIZE];
 	ASN1_TYPE pkcs8_asn = ASN1_TYPE_EMPTY;
+	gnutls_datum_t sder;
+	int ret;
 
 	if ((result =
 	     asn1_create_element(_gnutls_get_pkix(),
@@ -1201,8 +1222,6 @@ decode_private_key_info(const gnutls_datum_t * der,
 		result = _gnutls_asn2err(result);
 		goto error;
 	}
-	/* we only support RSA and DSA private keys.
-	 */
 
 	pkey->params.algo = gnutls_oid_to_pk(oid);
 	if (pkey->params.algo == GNUTLS_PK_UNKNOWN) {
@@ -1243,6 +1262,16 @@ decode_private_key_info(const gnutls_datum_t * der,
 		goto error;
 	}
 
+	/* check for provable parameters attribute */
+	ret = _x509_parse_attribute(pkcs8_asn, "attributes", OID_ATTR_PROV_SEED, 0, 1, &sder);
+	if (ret >= 0) { /* ignore it when not being present */
+		ret = _x509_decode_provable_seed(pkey, &sder);
+		gnutls_free(sder.data);
+		if (ret < 0) {
+			gnutls_assert();
+		}
+	}
+
 	result = 0;
 
 error:
diff --git a/lib/x509/prov-seed.c b/lib/x509/prov-seed.c
new file mode 100644
index 0000000000..b0f40c5802
--- /dev/null
+++ b/lib/x509/prov-seed.c
@@ -0,0 +1,135 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+#include "gnutls_int.h"
+#include <datum.h>
+#include <global.h>
+#include "errors.h"
+#include <common.h>
+#include <x509.h>
+#include <x509_int.h>
+#include <mpi.h>
+#include "prov-seed.h"
+
+int _x509_encode_provable_seed(gnutls_x509_privkey_t pkey, gnutls_datum_t *der)
+{
+
+	ASN1_TYPE c2;
+	int ret, result;
+	const char *oid;
+
+	oid = gnutls_digest_get_oid(pkey->params.palgo);
+	if (oid == NULL)
+		return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
+
+	if ((result =
+	     asn1_create_element(_gnutls_get_gnutls_asn(),
+				 "GNUTLS.ProvableSeed",
+				 &c2)) != ASN1_SUCCESS) {
+		gnutls_assert();
+		return _gnutls_asn2err(result);
+	}
+
+	result = asn1_write_value(c2, "seed", pkey->params.seed, pkey->params.seed_size);
+	if (result != ASN1_SUCCESS) {
+		gnutls_assert();
+		ret = _gnutls_asn2err(result);
+		goto cleanup;
+	}
+
+	result = asn1_write_value(c2, "algorithm", oid, 1);
+	if (result != ASN1_SUCCESS) {
+		gnutls_assert();
+		ret = _gnutls_asn2err(result);
+		goto cleanup;
+	}
+
+	ret = _gnutls_x509_der_encode(c2, "", der, 0);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	ret = 0;
+
+ cleanup:
+	asn1_delete_structure2(&c2, ASN1_DELETE_FLAG_ZEROIZE);
+	return ret;
+}
+
+int _x509_decode_provable_seed(gnutls_x509_privkey_t pkey, const gnutls_datum_t *der)
+{
+
+	ASN1_TYPE c2;
+	int ret, result;
+	char oid[MAX_OID_SIZE];
+	int oid_size;
+	gnutls_datum_t seed = {NULL, 0};
+
+	if ((result =
+	     asn1_create_element(_gnutls_get_gnutls_asn(),
+				 "GNUTLS.ProvableSeed",
+				 &c2)) != ASN1_SUCCESS) {
+		gnutls_assert();
+		return _gnutls_asn2err(result);
+	}
+
+	result = _asn1_strict_der_decode(&c2, der->data, der->size, NULL);
+	if (result != ASN1_SUCCESS) {
+		gnutls_assert();
+		ret = _gnutls_asn2err(result);
+		goto cleanup;
+	}
+
+	ret = _gnutls_x509_read_value(c2, "seed", &seed);
+	if (ret < 0) {
+		gnutls_assert();
+		goto cleanup;
+	}
+
+	if (seed.size <= sizeof(pkey->params.seed)) {
+		memcpy(pkey->params.seed, seed.data, seed.size);
+		pkey->params.seed_size = seed.size;
+	} else {
+		ret = 0; /* ignore struct */
+		_gnutls_debug_log("%s: ignoring ProvableSeed due to very long params\n", __func__);
+		goto cleanup;
+	}
+
+	oid_size = sizeof(oid);
+	result = asn1_read_value(c2, "algorithm", oid, &oid_size);
+	if (result != ASN1_SUCCESS) {
+		gnutls_assert();
+		ret = _gnutls_asn2err(result);
+		goto cleanup;
+	}
+
+	pkey->params.palgo = gnutls_oid_to_digest(oid);
+	pkey->params.flags |= GNUTLS_PK_FLAG_PROVABLE;
+
+	ret = 0;
+
+ cleanup:
+	gnutls_free(seed.data);
+	asn1_delete_structure2(&c2, ASN1_DELETE_FLAG_ZEROIZE);
+	return ret;
+}
diff --git a/lib/x509/prov-seed.h b/lib/x509/prov-seed.h
new file mode 100644
index 0000000000..55d6df0830
--- /dev/null
+++ b/lib/x509/prov-seed.h
@@ -0,0 +1,24 @@
+/*
+ * Copyright (C) 2017 Red Hat, Inc.
+ *
+ * Author: Nikos Mavrogiannopoulos
+ *
+ * This file is part of GnuTLS.
+ *
+ * The GnuTLS is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1 of
+ * the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>
+ *
+ */
+
+int _x509_encode_provable_seed(gnutls_x509_privkey_t pkey, gnutls_datum_t *der);
+int _x509_decode_provable_seed(gnutls_x509_privkey_t pkey, const gnutls_datum_t *der);
diff --git a/lib/x509/x509_int.h b/lib/x509/x509_int.h
index e886ac1acd..e325c06bf2 100644
--- a/lib/x509/x509_int.h
+++ b/lib/x509/x509_int.h
@@ -49,6 +49,8 @@
 #define HASH_OID_SHA3_384 "2.16.840.1.101.3.4.2.9"
 #define HASH_OID_SHA3_512 "2.16.840.1.101.3.4.2.10"
 
+#define OID_ATTR_PROV_SEED "1.3.6.1.4.1.2312.18.8.1"
+
 struct gnutls_x509_crl_iter {
 	/* This is used to optimize reads by gnutls_x509_crl_iter_crt_serial() */
 	ASN1_TYPE rcache;