Further restrict addresses that are cached when processing referrals

Use the owner name of the NS record as the bailwick apex name
when determining which additional records to cache, rather than
the name of the delegating zone (or a parent thereof).

(cherry picked from commit a41054e9e6)
This commit is contained in:
Mark Andrews 2025-08-14 14:35:46 +10:00 committed by Michał Kępień
parent 1967320413
commit ab97f6e9f4
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@ -6680,7 +6680,8 @@ mark_related(dns_name_t *name, dns_rdataset_t *rdataset, bool external,
* locally served zone.
*/
static inline bool
name_external(const dns_name_t *name, dns_rdatatype_t type, fetchctx_t *fctx) {
name_external(const dns_name_t *name, dns_rdatatype_t type, respctx_t *rctx) {
fetchctx_t *fctx = rctx->fctx;
isc_result_t result;
dns_forwarders_t *forwarders = NULL;
dns_name_t *apex = NULL;
@ -6690,7 +6691,7 @@ name_external(const dns_name_t *name, dns_rdatatype_t type, fetchctx_t *fctx) {
dns_namereln_t rel;
apex = (ISDUALSTACK(fctx->addrinfo) || !ISFORWARDER(fctx->addrinfo))
? fctx->domain
? rctx->ns_name != NULL ? rctx->ns_name : fctx->domain
: fctx->fwdname;
/*
@ -6794,7 +6795,7 @@ check_section(void *arg, const dns_name_t *addname, dns_rdatatype_t type,
result = dns_message_findname(rctx->query->rmessage, section, addname,
dns_rdatatype_any, 0, &name, NULL);
if (result == ISC_R_SUCCESS) {
external = name_external(name, type, fctx);
external = name_external(name, type, rctx);
if (type == dns_rdatatype_a) {
for (rdataset = ISC_LIST_HEAD(name->list);
rdataset != NULL;
@ -8447,7 +8448,7 @@ rctx_answer_scan(respctx_t *rctx) {
/*
* Don't accept DNAME from parent namespace.
*/
if (name_external(name, dns_rdatatype_dname, fctx)) {
if (name_external(name, dns_rdatatype_dname, rctx)) {
continue;
}
@ -8771,7 +8772,7 @@ rctx_authority_positive(respctx_t *rctx) {
dns_message_currentname(rctx->query->rmessage,
DNS_SECTION_AUTHORITY, &name);
if (!name_external(name, dns_rdatatype_ns, fctx) &&
if (!name_external(name, dns_rdatatype_ns, rctx) &&
dns_name_issubdomain(fctx->name, name))
{
dns_rdataset_t *rdataset = NULL;