dnsimple / erldns / 26228929595

87%

Build Type

push

github

Committed by web-flow

Commit Message

Fix CNAME chain truncation at zonecut (#349)

When a CNAME chain in the parent zone terminates at a delegated subzone, `maybe_add_zonecut_records/5` was filtering the answer section by the CNAME target, keeping only CNAMEs whose target crossed the zonecut. Any earlier hop whose target stayed inside the parent zone was dropped, leaving a response with no record matching QNAME — malformed per RFC 1034 §3.6.2.

This PR switches the filter to key off the CNAME owner name: keep every CNAME whose owner sits above the cut. The boundary-crossing CNAME still qualifies (its owner is in the parent zone), and any CNAME whose owner sits below the cut continues to be dropped. The semantic predicate has been the same since `b005ce6` (Dec 2018); the bug surfaces only on chains of ≥ 2 parent-zone CNAMEs ending at a delegated subzone, which the existing `resolve_authoritative_zone_cut_with_cnames` test did not cover.

A CT regression test (`resolve_authoritative_zone_cut_with_cname_chain_through_wildcard`) is added alongside the fix.

Fixes https://github.com/dnsimple/erldnsimple/issues/777

Coverage Stats

1 of 1 new or added line in 1 file covered. (100.0%)

2 existing lines in 2 files now uncovered.

1730 of 1988 relevant lines covered (87.02%)

1887.59 hits per line