From ab97f6e9f4405b61ba2051363104fc812cac5270 Mon Sep 17 00:00:00 2001 From: Mark Andrews Date: Thu, 14 Aug 2025 14:35:46 +1000 Subject: [PATCH] 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 a41054e9e606a61f1b3c8bc0c54e2f1059347165) --- lib/dns/resolver.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/lib/dns/resolver.c b/lib/dns/resolver.c index 6f4dedcc81..39969f9026 100644 --- a/lib/dns/resolver.c +++ b/lib/dns/resolver.c @@ -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;