[linux-cifs-client] [PATCH] cifs.upcall: make using ip address conditional on new option

[simo]

On Wed, 2009-08-26 at 06:29 -0400, Jeff Layton wrote:
> On Wed, 19 Aug 2009 13:30:37 -0400
> Jeff Layton <jlayton at redhat.com> wrote:
> 
> > Igor Mammedov pointed out that reverse resolving an IP address to get
> > the hostname portion of a principal could open a possible attack
> > vector. If an attacker were to gain control of DNS, then he could
> > redirect the mount to a server of his choosing, and fix the reverse
> > resolution to point to a hostname of his choosing (one where he has
> > the key for the corresponding cifs/ or host/ principal).
> > 
> > That said, we often trust DNS for other reasons and it can be useful
> > to do so. Make the code that allows trusting DNS to be enabled by
> > adding --trust-dns to the cifs.upcall invocation.
> > 
> > Signed-off-by: Jeff Layton <jlayton at redhat.com>
> > ---
> >  client/cifs.upcall.c |   62 ++++++++++++++++++++++++++++++++-----------------
> >  1 files changed, 40 insertions(+), 22 deletions(-)
> > 
> 
> Pushed to samba master branch (along with a corresponding manpage update).

We discussed this a few times in the past, I have no objections to the
patch, I am only wondering if the default shouldn't be reversed and make
only paranoid people disable it ?

Simo.

-- 
Simo Sorce
Samba Team GPL Compliance Officer <simo at samba.org>
Principal Software Engineer at Red Hat, Inc. <simo at redhat.com>