From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Chuck Lever <cel@kernel.org>
Cc: "Cen Zhang (Microsoft Security FORGE Labs)" <blbllhy@gmail.com>,
Jeff Layton <jlayton@kernel.org>, NeilBrown <neil@brown.name>,
Olga Kornievskaia <okorniev@redhat.com>,
Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
"J. Bruce Fields" <bfields@fieldses.org>,
linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org, AutonomousCodeSecurity@microsoft.com,
xmei5@asu.edu, tgopinath@linux.microsoft.com, kys@microsoft.com
Subject: Re: [PATCH] nfsd: hold cl_lock in client_has_state()
Date: Sat, 29 Aug 2026 07:52:31 +0200 [thread overview]
Message-ID: <2026082948-sleeve-blaming-b901@gregkh> (raw)
In-Reply-To: <978293e7-430d-4b11-9a29-1fb479cb0082@app.fastmail.com>
On Fri, Aug 28, 2026 at 09:45:33AM -0400, Chuck Lever wrote:
>
>
> On Fri, Aug 28, 2026, at 1:29 AM, Greg KH wrote:
> > On Fri, Aug 28, 2026 at 12:19:25AM -0400, Cen Zhang (Microsoft Security
> > FORGE Labs) wrote:
> >> client_has_openowners() walks clp->cl_openowners and reads so_stateids
> >> without clp->cl_lock. nfs4_put_stateowner() unhashes that openowner under
> >> cl_lock and then frees it, so a concurrent EXCHANGE_ID with mismatched
> >> creds can use-after-free the nfs4_openowner.
> >>
> >> BUG: KASAN: slab-use-after-free in client_has_state+0x10a/0x140
> >> fs/nfsd/nfs4state.c:3718 client_has_openowners()
> >> nfsd4_exchange_id
> >> nfsd4_proc_compound
> >> nfsd_dispatch
> >> svc_process
> >>
> >> Take clp->cl_lock while client_has_state() walks the openowner list.
> >>
> >> Fixes: 4eaea1342507 ("nfsd: improve client_has_state to check for unused openowners")
> >> Reported-by: Xiang Mei (Microsoft) <xmei5@asu.edu>
> >> Cc: AutonomousCodeSecurity@microsoft.com
> >> Cc: stable@vger.kernel.org
> >> Signed-off-by: Cen Zhang (Microsoft Security FORGE Labs) <blbllhy@gmail.com>
> >
> > Please use your microsoft.com email address, and not a random gmail.com
> > address. It's kind of odd that Microsoft would have to rely on Google
> > to send kernel patches :)
>
> Greg, would you prefer that I hold off on applying this to nfsd-testing
> until Cen can post this one again?
That's your call.
next prev parent reply other threads:[~2026-08-29 5:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-28 4:19 [PATCH] nfsd: hold cl_lock in client_has_state() Cen Zhang (Microsoft Security FORGE Labs)
2026-08-28 5:29 ` Greg KH
2026-08-28 12:33 ` Cen Zhang (Microsoft)
2026-08-28 13:45 ` Chuck Lever
2026-08-29 5:52 ` Greg Kroah-Hartman [this message]
2026-08-29 15:53 ` Chuck Lever
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