xfnw/plan9fox
1
0
Fork 0
Code Issues Pull requests Projects Releases Wiki Activity

dns: ignore spam addresses from cname answers

Browse source
This commit is contained in:
cinap_lenrek 2013-08-04 00:52:39 +02:00
parent 631ac3d2e2
commit 7dee88ec33
1 changed files with 13 additions and 1 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

14
sys/src/cmd/ndb/dnresolve.c
View file

@ -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){