diff options
| author | cinap_lenrek <cinap_lenrek@gmx.de> | 2013-08-04 00:52:39 +0200 |
|---|---|---|
| committer | cinap_lenrek <cinap_lenrek@gmx.de> | 2013-08-04 00:52:39 +0200 |
| commit | 7dee88ec33e281ae3771e95b6dfe35e9f6ce4fd4 (patch) | |
| tree | 064bdd5012b79293c54e6d4d4846f88897a52ff8 | |
| parent | 631ac3d2e229835e15d5c5e9906d118c19f1c0c1 (diff) | |
dns: ignore spam addresses from cname answers
| -rw-r--r-- | sys/src/cmd/ndb/dnresolve.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/sys/src/cmd/ndb/dnresolve.c b/sys/src/cmd/ndb/dnresolve.c index 56b8024f9..b21289c2b 100644 --- a/sys/src/cmd/ndb/dnresolve.c +++ b/sys/src/cmd/ndb/dnresolve.c @@ -1091,8 +1091,20 @@ procansw(Query *qp, DNSmsg *mp, uchar *srcip, int depth, Dest *p) unique(mp->ns); unique(mp->ar); - if(mp->an) + if(mp->an){ + /* + * only use cname answer when returned. some dns servers + * attach spam address records which poisons the cache. + */ + if((tp = rrremtype(&mp->an, Tcname)) != 0){ + if(mp->an){ + dnslog("removing spam %Q for %Q from %I", mp->an, tp, srcip); + rrfreelist(mp->an); + } + mp->an = tp; + } rrattach(mp->an, (mp->flags & Fauth) != 0); + } if(mp->ar) rrattach(mp->ar, Notauthoritative); if(mp->ns && !cfg.justforw){ |