diff options
| -rw-r--r-- | src/resolve/resolved-dns-answer.c | 37 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-answer.h | 2 | ||||
| -rw-r--r-- | src/resolve/resolved-dns-transaction.c | 37 |
3 files changed, 67 insertions, 9 deletions
diff --git a/src/resolve/resolved-dns-answer.c b/src/resolve/resolved-dns-answer.c index c359432a7a..f74e440531 100644 --- a/src/resolve/resolved-dns-answer.c +++ b/src/resolve/resolved-dns-answer.c @@ -821,3 +821,40 @@ void dns_answer_dump(DnsAnswer *answer, FILE *f) { fputc('\n', f); } } + +bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname) { + DnsResourceRecord *rr; + int r; + + assert(cname); + + /* Checks whether the answer contains a DNAME record that indicates that the specified CNAME record is + * synthesized from it */ + + if (cname->key->type != DNS_TYPE_CNAME) + return 0; + + DNS_ANSWER_FOREACH(rr, a) { + _cleanup_free_ char *n = NULL; + + if (rr->key->type != DNS_TYPE_DNAME) + continue; + if (rr->key->class != cname->key->class) + continue; + + r = dns_name_change_suffix(cname->cname.name, rr->dname.name, DNS_RESOURCE_KEY_NAME(rr->key), &n); + if (r < 0) + return r; + if (r == 0) + continue; + + r = dns_name_equal(n, DNS_RESOURCE_KEY_NAME(cname->key)); + if (r < 0) + return r; + if (r > 0) + return 1; + + } + + return 0; +} diff --git a/src/resolve/resolved-dns-answer.h b/src/resolve/resolved-dns-answer.h index 3eff21f8d0..1875fd6136 100644 --- a/src/resolve/resolved-dns-answer.h +++ b/src/resolve/resolved-dns-answer.h @@ -83,6 +83,8 @@ int dns_answer_remove_by_rr(DnsAnswer **a, DnsResourceRecord *rr); int dns_answer_copy_by_key(DnsAnswer **a, DnsAnswer *source, const DnsResourceKey *key, DnsAnswerFlags or_flags); int dns_answer_move_by_key(DnsAnswer **to, DnsAnswer **from, const DnsResourceKey *key, DnsAnswerFlags or_flags); +bool dns_answer_has_dname_for_cname(DnsAnswer *a, DnsResourceRecord *cname); + static inline unsigned dns_answer_size(DnsAnswer *a) { return a ? a->n_rrs : 0; } diff --git a/src/resolve/resolved-dns-transaction.c b/src/resolve/resolved-dns-transaction.c index 72ef283dde..393171a2ad 100644 --- a/src/resolve/resolved-dns-transaction.c +++ b/src/resolve/resolved-dns-transaction.c @@ -1827,6 +1827,12 @@ int dns_transaction_request_dnssec_keys(DnsTransaction *t) { if (r > 0) continue; + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r > 0) + continue; + name = DNS_RESOURCE_KEY_NAME(rr->key); r = dns_name_parent(&name); if (r < 0) @@ -2719,17 +2725,30 @@ int dns_transaction_validate_dnssec(DnsTransaction *t) { if (r < 0) return r; if (r > 0) { - /* This is a primary response - * to our question, and it - * failed validation. That's - * fatal. */ - t->answer_dnssec_result = result; - return 0; + + /* Look for a matching DNAME for this CNAME */ + r = dns_answer_has_dname_for_cname(t->answer, rr); + if (r < 0) + return r; + if (r == 0) { + /* Also look among the stuff we already validated */ + r = dns_answer_has_dname_for_cname(validated, rr); + if (r < 0) + return r; + } + + if (r == 0) { + /* This is a primary response to our question, and it failed validation. That's + * fatal. */ + t->answer_dnssec_result = result; + return 0; + } + + /* This is a primary response, but we do have a DNAME RR in the RR that can replay this + * CNAME, hence rely on that, and we can remove the CNAME in favour of it. */ } - /* This is just some auxiliary - * data. Just remove the RRset and - * continue. */ + /* This is just some auxiliary data. Just remove the RRset and continue. */ r = dns_answer_remove_by_key(&t->answer, rr->key); if (r < 0) return r; |