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-rw-r--r--src/libdnssec/key/ds.c115
1 files changed, 115 insertions, 0 deletions
diff --git a/src/libdnssec/key/ds.c b/src/libdnssec/key/ds.c
new file mode 100644
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--- /dev/null
+++ b/src/libdnssec/key/ds.c
@@ -0,0 +1,115 @@
+/* Copyright (C) 2018 CZ.NIC, z.s.p.o. <knot-dns@labs.nic.cz>
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+#include "libdnssec/key.h"
+#include "libdnssec/key/internal.h"
+#include "libdnssec/shared/dname.h"
+#include "libdnssec/shared/shared.h"
+#include "libdnssec/shared/binary_wire.h"
+
+#include <gnutls/gnutls.h>
+#include <gnutls/crypto.h>
+
+/*!
+ * Convert DNSSEC DS digest algorithm to GnuTLS digest algorithm.
+ */
+static gnutls_digest_algorithm_t lookup_algorithm(dnssec_key_digest_t algorithm)
+{
+ switch (algorithm) {
+ case DNSSEC_KEY_DIGEST_SHA1: return GNUTLS_DIG_SHA1;
+ case DNSSEC_KEY_DIGEST_SHA256: return GNUTLS_DIG_SHA256;
+ case DNSSEC_KEY_DIGEST_SHA384: return GNUTLS_DIG_SHA384;
+ default:
+ return GNUTLS_DIG_UNKNOWN;
+ };
+}
+
+_public_
+bool dnssec_algorithm_digest_support(dnssec_key_digest_t algo)
+{
+ return lookup_algorithm(algo) != GNUTLS_DIG_UNKNOWN;
+}
+
+static void wire_write_digest(wire_ctx_t *wire,
+ gnutls_hash_hd_t digest, int digest_size)
+{
+ assert(wire_ctx_available(wire) >= digest_size);
+ gnutls_hash_output(digest, wire->position);
+ wire->position += digest_size;
+}
+
+_public_
+int dnssec_key_create_ds(const dnssec_key_t *key,
+ dnssec_key_digest_t ds_algorithm,
+ dnssec_binary_t *rdata_ptr)
+{
+ if (!key || !rdata_ptr) {
+ return DNSSEC_EINVAL;
+ }
+
+ if (!key->dname) {
+ return DNSSEC_INVALID_KEY_NAME;
+ }
+
+ if (!key->public_key){
+ return DNSSEC_INVALID_PUBLIC_KEY;
+ }
+
+ gnutls_digest_algorithm_t algorithm = lookup_algorithm(ds_algorithm);
+ if (algorithm == GNUTLS_DIG_UNKNOWN) {
+ return DNSSEC_INVALID_DS_ALGORITHM;
+ }
+
+ // compute DS hash
+
+ _cleanup_hash_ gnutls_hash_hd_t digest = NULL;
+ int r = gnutls_hash_init(&digest, algorithm);
+ if (r < 0) {
+ return DNSSEC_DS_HASHING_ERROR;
+ }
+
+ if (gnutls_hash(digest, key->dname, dname_length(key->dname)) != 0 ||
+ gnutls_hash(digest, key->rdata.data, key->rdata.size) != 0
+ ) {
+ return DNSSEC_DS_HASHING_ERROR;
+ }
+
+ // build DS RDATA
+
+ int digest_size = gnutls_hash_get_len(algorithm);
+ if (digest_size == 0) {
+ return DNSSEC_DS_HASHING_ERROR;
+ }
+
+ dnssec_binary_t rdata = { 0 };
+ r = dnssec_binary_alloc(&rdata, 4 + digest_size);
+ if (r != DNSSEC_EOK) {
+ return r;
+ }
+
+ wire_ctx_t wire = binary_init(&rdata);
+ wire_ctx_write_u16(&wire, dnssec_key_get_keytag(key));
+ wire_ctx_write_u8(&wire, dnssec_key_get_algorithm(key));
+ wire_ctx_write_u8(&wire, ds_algorithm);
+ wire_write_digest(&wire, digest, digest_size);
+ assert(wire_ctx_offset(&wire) == wire.size);
+
+ *rdata_ptr = rdata;
+
+ return DNSSEC_EOK;
+}