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Subject: Re: nfsd vurlerability submit
From:   Chuck Lever <chuck.lever@oracle.com>
In-Reply-To: <CAHk-=wic1CEkj_vjf3dUWv41=aKeazSW5ugGOfYsKQZnihQhMw@mail.gmail.com>
Date:   Thu, 14 Jan 2021 13:35:37 -0500
Cc:     Bruce Fields <bfields@fieldses.org>,
        Trond Myklebust <trondmy@hammerspace.com>,
        Linux NFS Mailing List <linux-nfs@vger.kernel.org>
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To:     Linus Torvalds <torvalds@linuxfoundation.org>
Precedence: bulk


> On Jan 14, 2021, at 1:29 PM, Linus Torvalds =
<torvalds@linuxfoundation.org> wrote:
>=20
> On Thu, Jan 14, 2021 at 10:08 AM bfields@fieldses.org
> <bfields@fieldses.org> wrote:
>>=20
>> I dug around a bit and couldn't find the idea of using filehandle
>> guessing plus mountd's following of symlinks to get access to other
>> filesystems.  That's kind of interesting.
>=20
> [ Other people removed from cc, this is just a question about nfsd =
cleanliness ]
>=20
> I missed if Trond's suggestion to at least fix up ".." to have the
> same filehandle as "." for the top export directory was done.

If I understand your question correctly... there is a commit in
linux-next that simply doesn't return any filehandle for ".."
in the root directory.

=
https://git.kernel.org/pub/scm/linux/kernel/git/cel/linux.git/commit/?h=3D=
for-next&id=3D51b2ee7d006a736a9126e8111d1f24e4fd0afaa6

I intend to send you a PR after a few more days of soak time,
unless you'd like me to send it now.


--
Chuck Lever