Re: [PATCH 2/4] svcrpc: fix error-handling on badd gssproxy downcall

[Simo Sorce <simo@redhat.com>]

On Thu, 2013-10-10 at 15:23 -0400, J. Bruce Fields wrote:
> On Thu, Oct 10, 2013 at 11:37:12AM -0400, Simo Sorce wrote:
> > On Thu, 2013-10-10 at 11:15 -0400, J. Bruce Fields wrote:
> > > From: "J. Bruce Fields" <bfields@redhat.com>
> > > 
> > > For every other problem here we bail out with an error, but here for
> > > some reason we're setting a negative cache entry (with, note, an
> > > undefined expiry).
> > > 
> > > It seems simplest just to bail out in the same way as we do in other
> > > cases.
> > > 
> > > Cc: Simo Sorce <simo@redhat.com>
> > > Reported-by: Andi Kleen <andi@firstfloor.org>
> > > Signed-off-by: J. Bruce Fields <bfields@redhat.com>
> > > ---
> > >  net/sunrpc/auth_gss/svcauth_gss.c |    4 ++--
> > >  1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
> > > index 09fb638..008cdad 100644
> > > --- a/net/sunrpc/auth_gss/svcauth_gss.c
> > > +++ b/net/sunrpc/auth_gss/svcauth_gss.c
> > > @@ -1167,8 +1167,8 @@ static int gss_proxy_save_rsc(struct cache_detail *cd,
> > >  	if (!ud->found_creds) {
> > >  		/* userspace seem buggy, we should always get at least a
> > >  		 * mapping to nobody */
> > > -		dprintk("RPC:       No creds found, marking Negative!\n");
> > > -		set_bit(CACHE_NEGATIVE, &rsci.h.flags);
> > > +		dprintk("RPC:       No creds found!\n");
> > > +		goto out;
> > >  	} else {
> > >  
> > >  		/* steal creds */
> > 
> > IIRC, we are doing this to avoid rapid upcall loops in the kernel, where
> > we keep hammering upcalls out and keep getting an error back.
> 
> Looks like returning an error instead results in closing the connection
> to the client, so, depends how the client replies I guess.
> 
> In any case I don't see why we'd treat this particular gss-proxy bug
> differently than we would any other (like, say, passing down bad xdr, or
> a gss context that we can't import).

Uhmm I did not recall that, I guess the change is ok then.

Simo.

> --b.
> 
> > I am not sure it is wise to not set a temp negative cache here.
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-- 
Simo Sorce * Red Hat, Inc * New York