draft-fregly-dnsop-slh-dsa-mtl-dnssec support

configure.ac

@@ -988,6 +988,24 @@ case "$enable_log_role" in
                 ;;
 esac
 
+AC_ARG_ENABLE(draft-slh-dsa-mtl, AS_HELP_STRING([--enable-draft-slh-dsa-mtl[=optcode]],[Enables responding with SLH-DSA-MTL signatures as described in draft-fregly-dnsop-slh-dsa-mtl-dnssec. Opcode defaults to 65050]))
+mtl_mode_full_code=""
+case "$enable_draft_slh_dsa_mtl" in
+	""|no)
+		;;
+	yes)
+		AC_DEFINE_UNQUOTED([MTL_MODE_FULL_CODE], [65050], [Define this to enable answering with the full SLH-DSA-MTL signatures when queried with this EDNS opcode])
+		;;
+	*)
+		AC_DEFINE_UNQUOTED([MTL_MODE_FULL_CODE], [$enable_draft_slh_dsa_mtl], [Define this to enable answering with the full SLH-DSA-MTL signatures when queried with this EDNS opcode])
+		;;
+esac
+mtl_dnssec_alg=50
+AC_ARG_WITH([slh-dsa-mtl-dnssec-alg],
+	AS_HELP_STRING([--with-slh-dsa-mtl-dnssec-alg=alg],[The algorithm used for SLH-DSA-MTL keys and signatures. Only relevant with draft-slh-dsa-mtl enabled. Defaults to 50.]),
+	[mtl_dnssec_alg=$withval])
+AC_SUBST(mtl_dnssec_alg)
+AC_DEFINE_UNQUOTED(MTL_DNSSEC_ALG, [$mtl_dnssec_alg], [The algorithm used for SLH-DSA-MTL keys and signatures. Default 50.])
 
 AC_ARG_ENABLE(memclean, AS_HELP_STRING([--enable-memclean],[Cleanup memory (at exit) for eg. valgrind, memcheck]))
 if test "$enable_memclean" = "yes"; then AC_DEFINE_UNQUOTED([MEMCLEAN], [1], [Define this to cleanup memory at exit (eg. for valgrind, etc.)])

edns.c

@@ -70,6 +70,9 @@ edns_init_record(edns_record_type *edns)
 	edns->opt_reserved_space = 0;
 	edns->dnssec_ok = 0;
 	edns->nsid = 0;
+#ifdef MTL_MODE_FULL_CODE
+	edns->mtl_mode_full = 0;
+#endif
 	edns->cookie_status = COOKIE_NOT_PRESENT;
 	edns->cookie_len = 0;
 	edns->ede = -1; /* -1 means no Extended DNS Error */
@@ -116,6 +119,11 @@ edns_handle_option(uint16_t optcode, uint16_t optlen, buffer_type* packet,
 			buffer_skip(packet, optlen);
 		}
 		break;
+#ifdef MTL_MODE_FULL_CODE
+	case MTL_MODE_FULL_CODE:
+		edns->mtl_mode_full = 1;
+		break;
+#endif
 	default:
 		buffer_skip(packet, optlen);
 		break;

edns.h

@@ -65,6 +65,9 @@ struct edns_record
 	int                ede; /* RFC 8914 - Extended DNS Errors */
 	char*              ede_text; /* RFC 8914 - Extended DNS Errors text*/
 	uint16_t           ede_text_len;
+#ifdef MTL_MODE_FULL_CODE
+	int                mtl_mode_full;
+#endif
 };
 typedef struct edns_record edns_record_type;
 

namedb.c

@@ -656,6 +656,28 @@ rr_rrsig_type_covered(rr_type* rr)
 	return ntohs(* (uint16_t *) rdata_atom_data(rr->rdatas[0]));
 }
 
+#ifdef MTL_MODE_FULL_CODE
+uint8_t
+rr_rrsig_algorithm(rr_type* rr)
+{
+	assert(rr->type == TYPE_RRSIG);
+	assert(rr->rdata_count > 1);
+	assert(rdata_atom_size(rr->rdatas[1]) == sizeof(uint8_t));
+
+	return *(uint8_t*)rdata_atom_data(rr->rdatas[1]);
+}
+
+uint16_t
+rr_rrsig_keytag(rr_type* rr)
+{
+	assert(rr->type == TYPE_RRSIG);
+	assert(rr->rdata_count > 6);
+	assert(rdata_atom_size(rr->rdatas[6]) == sizeof(uint16_t));
+
+	return *(uint16_t*)rdata_atom_data(rr->rdatas[6]);
+}
+#endif
+
 zone_type *
 namedb_find_zone(namedb_type* db, const dname_type* dname)
 {

namedb.h

@@ -333,6 +333,18 @@ static inline const char* domain_to_string_buf(domain_type* domain, char *buf)
  */
 uint16_t rr_rrsig_type_covered(rr_type* rr);
 
+#ifdef MTL_MODE_FULL_CODE
+/*
+ * The algorithm field of the specified RRSIG RR
+ */
+uint8_t rr_rrsig_algorithm(rr_type* rr);
+
+/*
+ * The keytag field of the specified RRSIG RR
+ */
+uint16_t rr_rrsig_keytag(rr_type* rr);
+#endif
+
 struct namedb
 {
 	region_type*       region;

packet.c

@@ -74,6 +74,66 @@ packet_encode_rr(query_type *q, domain_type *owner, rr_type *rr, uint32_t ttl)
 	buffer_skip(q->packet, sizeof(rdlength));
 
 	for (j = 0; j < rr->rdata_count; ++j) {
+#ifdef MTL_MODE_FULL_CODE
+		rrset_type *apex_rrsigs;
+
+		if(rr->type == TYPE_RRSIG
+		&& j == 8 /* The signature data */
+		&& q->edns.mtl_mode_full
+		&& rr_rrsig_type_covered(rr) != TYPE_SOA
+		&& rr_rrsig_algorithm(rr) == MTL_DNSSEC_ALG
+		&& (apex_rrsigs = domain_find_rrset(
+				q->zone->apex, q->zone, TYPE_RRSIG))) {
+			size_t k;
+
+			buffer_write_u8(q->packet, 1); /* Full signature */
+			/* First the condensed signature */
+			buffer_write(q->packet,
+				rdata_atom_data(rr->rdatas[j])+1,
+				rdata_atom_size(rr->rdatas[j])-1);
+
+			for(k = 0; k < apex_rrsigs->rr_count; k++) {
+				rr_type* rrsig = &apex_rrsigs->rrs[k];
+				uint16_t sibling_count;
+
+				if(rrsig->rdata_count < 9
+				|| rr_rrsig_type_covered(rrsig) != TYPE_SOA
+				|| rr_rrsig_algorithm(rrsig) != MTL_DNSSEC_ALG
+				|| rr_rrsig_keytag(rrsig)!=rr_rrsig_keytag(rr))
+					continue;
+				/* MTL-Type = 1
+				 * Randomizer = 16
+				 * Flags = 2
+				 * Series Identifier = 8
+				 * Leaf Index = 4
+				 * Target Rung Left Index = 4
+				 * Target Rung Right Index = 4
+				 * 1 + 16 + 2 + 8 + 4 + 4 + 4 = 39
+				 * Next 2 (uint16_t) is Sibling Count
+				 */
+				if(rdata_atom_size(rrsig->rdatas[8]) < 41)
+					continue;
+				sibling_count = ntohs(*(uint16_t *)(
+				   rdata_atom_data(rrsig->rdatas[8]) + 39));
+				/* Each sibling is 16 bytes, skipping them
+				 * skips the complete Authentication Path
+				 * and takes us to the remainder that needs
+				 * to be appended to the RRSIG signature data.
+				 */
+				if(rdata_atom_size(rrsig->rdatas[8]) < 41 +
+						16 * sibling_count)
+					continue;
+				buffer_write(q->packet,
+					rdata_atom_data(rrsig->rdatas[8]) +
+						41 + 16 * sibling_count,
+					rdata_atom_size(rrsig->rdatas[8]) -
+						41 - 16 * sibling_count);
+				break;
+			}
+			if(k == apex_rrsigs->rr_count) {
+			}
+		} else
+#endif
 		switch (rdata_atom_wireformat_type(rr->type, j)) {
 		case RDATA_WF_COMPRESSED_DNAME:
 			encode_dname(q, rdata_atom_domain(rr->rdatas[j]));

zonec.c

@@ -493,7 +493,12 @@ apex_rrset_checks(namedb_type* db, rrset_type* rrset, domain_type* domain)
 		zone->ns_rrset = rrset;
 	} else if (rrset_rrtype(rrset) == TYPE_RRSIG) {
 		for (i = 0; i < rrset->rr_count; ++i) {
-			if(rr_rrsig_type_covered(&rrset->rrs[i])==TYPE_DNSKEY){
+			if(rr_rrsig_type_covered(&rrset->rrs[i])==TYPE_DNSKEY
+#ifdef MTL_MODE_FULL_CODE
+			|| (rr_rrsig_type_covered(&rrset->rrs[i])==TYPE_SOA &&
+			    rr_rrsig_algorithm(&rrset->rrs[i])==MTL_DNSSEC_ALG)
+#endif
+			){
 				zone->is_secure = 1;
 				break;
 			}