From: =?utf-8?b?VmxhZGltw61yIMSMdW7DoXQ=?= Date: Mon, 12 Apr 2021 15:23:02 +0200 Subject: [PATCH] validator: avoid assertion in an edge-case Case: NSEC3 with too many iterations used for a positive wildcard proof. To really fix the answers, this also needed fixing the `any_rank` part which I somehow forgot in commit 7107faebc :-( --- lib/dnssec/nsec3.c | 7 +++++++ lib/dnssec/nsec3.h | 1 + lib/layer/validate.c | 3 ++- 3 files changed, 10 insertions(+), 1 deletion(-) diff --git a/lib/dnssec/nsec3.c b/lib/dnssec/nsec3.c index e9e536a..f3a48c0 100644 --- a/lib/dnssec/nsec3.c +++ b/lib/dnssec/nsec3.c @@ -596,6 +596,13 @@ int kr_nsec3_wildcard_answer_response_check(const knot_pkt_t *pkt, knot_section_ if (rrset->type != KNOT_RRTYPE_NSEC3) { continue; } + if (knot_nsec3_iters(rrset->rrs.rdata) > KR_NSEC3_MAX_ITERATIONS) { + /* Avoid hashing with too many iterations. + * If we get here, the `sname` wildcard probably ends up bogus, + * but it gets downgraded to KR_RANK_INSECURE when validator + * gets to verifying one of these over-limit NSEC3 RRs. */ + continue; + } int ret = covers_name(&flags, rrset, sname); if (ret != 0) { return ret; diff --git a/lib/dnssec/nsec3.h b/lib/dnssec/nsec3.h index 1e316f5..0fdbfce 100644 --- a/lib/dnssec/nsec3.h +++ b/lib/dnssec/nsec3.h @@ -39,6 +39,7 @@ int kr_nsec3_name_error_response_check(const knot_pkt_t *pkt, knot_section_t sec * KNOT_ERANGE - NSEC3 RR that covers a wildcard * has been found, but has opt-out flag set; * otherwise - error. + * Records over KR_NSEC3_MAX_ITERATIONS are skipped, so you probably get kr_error(ENOENT). */ int kr_nsec3_wildcard_answer_response_check(const knot_pkt_t *pkt, knot_section_t section_id, const knot_dname_t *sname, int trim_to_next); diff --git a/lib/layer/validate.c b/lib/layer/validate.c index cf5dda2..cf5c88a 100644 --- a/lib/layer/validate.c +++ b/lib/layer/validate.c @@ -894,7 +894,8 @@ static void rank_records(struct kr_query *qry, bool any_rank, enum kr_rank rank_ bailiwick) < 0) { continue; } - if (kr_rank_test(entry->rank, KR_RANK_INITIAL) + if (any_rank + || kr_rank_test(entry->rank, KR_RANK_INITIAL) || kr_rank_test(entry->rank, KR_RANK_TRY) || kr_rank_test(entry->rank, KR_RANK_MISSING)) { kr_rank_set(&entry->rank, rank_to_set);