1 files changed, 91 insertions, 0 deletions
diff --git a/src/libdnssec/key/dnskey.c b/src/libdnssec/key/dnskey.c
new file mode 100644
index 0000000..6360700
--- /dev/null
+++ b/src/libdnssec/key/dnskey.c
@@ -0,0 +1,91 @@
+/*  Copyright (C) 2022 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 <https://www.gnu.org/licenses/>.
+ */
+
+#include "libdnssec/binary.h"
+#include "libdnssec/error.h"
+#include "libdnssec/key/dnskey.h"
+#include "libdnssec/key/convert.h"
+#include "libdnssec/shared/binary_wire.h"
+
+/* -- internal API --------------------------------------------------------- */
+
+/*!
+ * Update 'Public key' field of DNSKEY RDATA.
+ */
+int dnskey_rdata_set_pubkey(dnssec_binary_t *rdata, const dnssec_binary_t *pubkey)
+{
+	assert(rdata);
+	assert(pubkey);
+
+	size_t new_size = DNSKEY_RDATA_OFFSET_PUBKEY + pubkey->size;
+	int result = dnssec_binary_resize(rdata, new_size);
+	if (result != DNSSEC_EOK) {
+		return result;
+	}
+
+	wire_ctx_t wire = binary_init(rdata);
+	wire_ctx_set_offset(&wire, DNSKEY_RDATA_OFFSET_PUBKEY);
+	binary_write(&wire, pubkey);
+	assert(wire_ctx_offset(&wire) == rdata->size);
+
+	return DNSSEC_EOK;
+}
+
+/*!
+ * Create a GnuTLS public key from DNSKEY RDATA.
+ *
+ * \param rdata    DNSKEY RDATA.
+ * \param key_ptr  Resulting public key.
+ */
+int dnskey_rdata_to_crypto_key(const dnssec_binary_t *rdata, gnutls_pubkey_t *key_ptr)
+{
+	assert(rdata);
+	assert(key_ptr);
+
+	uint8_t algorithm = 0, protocol = 0, flags_hi = 0;
+	dnssec_binary_t rdata_pubkey = { 0 };
+
+	wire_ctx_t wire = binary_init(rdata);
+
+	wire_ctx_set_offset(&wire, DNSKEY_RDATA_OFFSET_FLAGS);
+	flags_hi = wire_ctx_read_u8(&wire);
+	wire_ctx_set_offset(&wire, DNSKEY_RDATA_OFFSET_PROTOCOL);
+	protocol = wire_ctx_read_u8(&wire);
+	if (flags_hi != 0x1 || protocol != 0x3) {
+		return DNSSEC_INVALID_PUBLIC_KEY;
+	}
+
+	wire_ctx_set_offset(&wire, DNSKEY_RDATA_OFFSET_ALGORITHM);
+	algorithm = wire_ctx_read_u8(&wire);
+	wire_ctx_set_offset(&wire, DNSKEY_RDATA_OFFSET_PUBKEY);
+	binary_available(&wire, &rdata_pubkey);
+
+	gnutls_pubkey_t key = NULL;
+	int result = gnutls_pubkey_init(&key);
+	if (result != GNUTLS_E_SUCCESS) {
+		return DNSSEC_ENOMEM;
+	}
+
+	result = convert_dnskey_to_pubkey(algorithm, &rdata_pubkey, key);
+	if (result != DNSSEC_EOK) {
+		gnutls_pubkey_deinit(key);
+		return result;
+	}
+
+	*key_ptr = key;
+
+	return DNSSEC_EOK;
+}