diff options
| -rw-r--r-- | src/resolve/resolved-dns-server.c | 29 |
1 files changed, 22 insertions, 7 deletions
diff --git a/src/resolve/resolved-dns-server.c b/src/resolve/resolved-dns-server.c index 6732030d65..949c0d66e1 100644 --- a/src/resolve/resolved-dns-server.c +++ b/src/resolve/resolved-dns-server.c @@ -248,13 +248,18 @@ void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLeve if (s->possible_feature_level == level) s->n_failed_udp = 0; + /* If the RRSIG data is missing, then we can only validate EDNS0 at max */ + if (s->packet_rrsig_missing && level >= DNS_SERVER_FEATURE_LEVEL_DO) + level = DNS_SERVER_FEATURE_LEVEL_DO - 1; + + /* If the OPT RR got lost, then we can only validate UDP at max */ + if (s->packet_bad_opt && level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + level = DNS_SERVER_FEATURE_LEVEL_EDNS0 - 1; + + /* Even if we successfully receive a reply to a request announcing support for large packets, + that does not mean we can necessarily receive large packets. */ if (level == DNS_SERVER_FEATURE_LEVEL_LARGE) - /* Even if we successfully receive a reply to a request announcing support for large packets, - that does not mean we can necessarily receive large packets. */ - dns_server_verified(s, DNS_SERVER_FEATURE_LEVEL_LARGE - 1); - else - /* A successful UDP reply, verifies UDP, ENDS0 and DO levels */ - dns_server_verified(s, level); + level = DNS_SERVER_FEATURE_LEVEL_LARGE - 1; } else if (protocol == IPPROTO_TCP) { @@ -262,9 +267,11 @@ void dns_server_packet_received(DnsServer *s, int protocol, DnsServerFeatureLeve s->n_failed_tcp = 0; /* Successful TCP connections are only useful to verify the TCP feature level. */ - dns_server_verified(s, DNS_SERVER_FEATURE_LEVEL_TCP); + level = DNS_SERVER_FEATURE_LEVEL_TCP; } + dns_server_verified(s, level); + /* Remember the size of the largest UDP packet we received from a server, we know that we can always announce support for packets with at least this size. */ @@ -322,6 +329,10 @@ void dns_server_packet_rrsig_missing(DnsServer *s, DnsServerFeatureLevel level) if (level < DNS_SERVER_FEATURE_LEVEL_DO) return; + /* If the RRSIG RRs are missing, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_DO) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_DO-1; + s->packet_rrsig_missing = true; } @@ -331,6 +342,10 @@ void dns_server_packet_bad_opt(DnsServer *s, DnsServerFeatureLevel level) { if (level < DNS_SERVER_FEATURE_LEVEL_EDNS0) return; + /* If the OPT RR got lost, we have to downgrade what we previously verified */ + if (s->verified_feature_level >= DNS_SERVER_FEATURE_LEVEL_EDNS0) + s->verified_feature_level = DNS_SERVER_FEATURE_LEVEL_EDNS0-1; + s->packet_bad_opt = true; } |