On Wed, Mar 07, 2018 at 08:30:25AM +0100, Gilles Chehade wrote:
> On Tue, Mar 06, 2018 at 01:13:11PM +0100, Otto Moerbeek wrote:
> > On Tue, Mar 06, 2018 at 10:46:23AM +0100, Jan Johansson wrote:
> >
> > > >Synopsis: Bus error in smtpctl spf walk (on certain domains)
> > > >Category: user
> > > >Environment:
> > > System : OpenBSD 6.3
> > > Details : OpenBSD 6.3-beta (GENERIC.MP) #26: Fri Mar 2 22:56:04
> > > MST 2018
> > >
> > > [email protected]:/usr/src/sys/arch/amd64/compile/GENERIC.MP
> > >
> > > Architecture: OpenBSD.amd64
> > > Machine : amd64
> > > >Description:
> > > Got a mail with "Return-Path:
> > > [email protected]" and wanted to add it to my white
> > > list but smtpctl spf walk says "Bus error". Other domains like
> > > facebookmail.com works without problem.
> > > http://www.kitterman.com/spf/validate.html seems to think
> > > sendgrid.meetup.com has a valid record.
> > >
> > > >How-To-Repeat:
> > > echo sendgrid.meetup.com | smtpctl spf walk
> > >
> > > >Fix:
> > > Not known
> >
> > Try this,
> >
> > -Otto
> >
> > Index: spfwalk.c
> > ===================================================================
> > RCS file: /cvs/src/usr.sbin/smtpd/spfwalk.c,v
> > retrieving revision 1.5
> > diff -u -p -r1.5 spfwalk.c
> > --- spfwalk.c 26 Jan 2018 08:00:54 -0000 1.5
> > +++ spfwalk.c 6 Mar 2018 12:12:42 -0000
> > @@ -140,6 +140,8 @@ dispatch_txt(struct dns_rr *rr)
> > char *end;
> > ssize_t n;
> >
> > + if (rr->rr_type != T_TXT)
> > + return;
> > n = parse_txt(rr->rr.other.rdata, rr->rr.other.rdlen, buf, sizeof(buf));
> > if (n == -1 || n == sizeof(buf))
> > return;
> >
>
> ok gilles@, the check can't hurt
>
> I'm curious why we can even get rr_type != T_TXT when res_query_async()
> is called with a type == T_TXT though, I'll look into this to ensure we
> don't use a broken pattern in multiple places.
It is because there's a cname record involved:
;; QUESTION SECTION:
;sendgrid.meetup.com. IN TXT
;; ANSWER SECTION:
sendgrid.meetup.com. 300 IN CNAME u3863915.wl166.sendgrid.net.
u3863915.wl166.sendgrid.net. 1800 IN TXT "v=spf1 include:sendgrid.net
~all"
-Otto
