On Wed, Aug 05, 2020 at 03:17:54PM -0400, Chuck Lever wrote:
> Hi Bruce-
>
> > On Aug 5, 2020, at 3:10 PM, bfields@xxxxxxxxxxxx wrote:
> >
> > From: "J. Bruce Fields" <bfields@xxxxxxxxxx>
> >
> > If an NFSv2/v3 client breaks an NFSv4 client's delegation, it will hit a
> > NULL dereference in nfsd_breaker_owns_lease().
> >
> > Easily reproduceable with for example
> >
> > mount -overs=4.2 server:/export /mnt/
> > sleep 1h </mnt/file &
> > mount -overs=3 server:/export /mnt2/
> > touch /mnt2/file
> >
> > Reported-by: Robert Dinse <nanook@xxxxxxxxxx>
> > Fixes: 28df3d1539de50 ("nfsd: clients don't need to break their own delegations")
>
> May I add
>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=208807
>
> And send this in the first NFSD v5.9 -rc pull request?
Sounds good, thanks!
--b.
>
>
> > Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> > ---
> > fs/nfsd/nfs4state.c | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
> > index 9fc0a1b9e4dd..45f3832d70d4 100644
> > --- a/fs/nfsd/nfs4state.c
> > +++ b/fs/nfsd/nfs4state.c
> > @@ -4597,6 +4597,8 @@ static bool nfsd_breaker_owns_lease(struct file_lock *fl)
> > if (!i_am_nfsd())
> > return NULL;
> > rqst = kthread_data(current);
> > + if (!rqst->rq_lease_breaker)
> > + return NULL;
> > clp = *(rqst->rq_lease_breaker);
> > return dl->dl_stid.sc_client == clp;
> > }
> > --
> > 2.26.2
> >
>
> --
> Chuck Lever
>
>
