From: Vivek Goyal <vgoyal@redhat.com>
To: Miklos Szeredi <miklos@szeredi.hu>
Cc: linux-fsdevel@vger.kernel.org, virtio-fs-list <virtio-fs@redhat.com>
Subject: Re: [PATCH v3 3/6] fuse: setattr should set FATTR_KILL_PRIV upon size change
Date: Wed, 11 Nov 2020 14:16:20 -0500 [thread overview]
Message-ID: <20201111191620.GA1577294@redhat.com> (raw)
In-Reply-To: <CAJfpegvvGL=GJX0a+cDUVhX754NibudTvHvtrBrCnk-FEnfQ6A@mail.gmail.com>
On Wed, Nov 11, 2020 at 02:54:43PM +0100, Miklos Szeredi wrote:
> On Fri, Nov 6, 2020 at 6:18 PM Vivek Goyal <vgoyal@redhat.com> wrote:
>
> > I think it does not hurt to start passing FATTR_KILL_PRIV for chown()
> > as well. In that case, server will always clear caps on chown but
> > clear suid/sgid only if FATTR_KILL_PRIV is set. (Which will always
> > be set).
>
> Okay.
>
> More thoughts for FUSE_HANDLE_KILLPRIV_V2:
>
> - clear "security.capability" on write, truncate and chown unconditionally
> - clear suid/sgid if
> o setattr has FATTR_SIZE and FATTR_KILL_PRIV
> o setattr has FATTR_UID or FATTR_GID
> o open has O_TRUNC and FUSE_OPEN_KILL_PRIV
> o write has FUSE_WRITE_KILL_PRIV
>
> Kernel has:
> ATTR_KILL_PRIV -> clear "security.capability"
> ATTR_KILL_SUID -> clear S_ISUID
> ATTR_KILL_SGID -> clear S_ISGID if executable
>
> Fuse has:
> FUSE_*KILL_PRIV -> clear S_ISUID and S_ISGID if executable
>
> So the fuse meaning of FUSE_*KILL_PRIV has a complementary meaning to
> that of ATTR_KILL_PRIV, which is somewhat confusing. Also "PRIV"
> implies all privileges, including "security.capability" but the fuse
> ones relate to suid/sgid only.
>
> How about FUSE_*KILL_SUIDGID (FUSE_WRITE_KILL_SUIDGID being an alias
> for FUSE_WRITE_KILL_PRIV)?
Hi Miklos,
Renaming FUSE_*KILL_PRIV to FUSE_*KILL_SUIDSGID sounds good. For a
breif moment I was also thinking that these FUSE_*KILL_PRIV and
and ATTR_KILL_PRIV are not exactly mapping. Glad you caught it
and made the situation better.
Thanks
Vivek
next prev parent reply other threads:[~2020-11-11 19:16 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-09 18:15 [PATCH v3 0/6] fuse: Implement FUSE_HANDLE_KILLPRIV_V2 and enable SB_NOSEC Vivek Goyal
2020-10-09 18:15 ` [PATCH v3 1/6] fuse: Introduce the notion of FUSE_HANDLE_KILLPRIV_V2 Vivek Goyal
2020-10-09 18:15 ` [PATCH v3 2/6] fuse: Set FUSE_WRITE_KILL_PRIV in cached write path Vivek Goyal
2020-10-09 18:15 ` [PATCH v3 3/6] fuse: setattr should set FATTR_KILL_PRIV upon size change Vivek Goyal
2020-11-06 14:39 ` Miklos Szeredi
2020-11-06 17:18 ` Vivek Goyal
2020-11-11 13:54 ` Miklos Szeredi
2020-11-11 16:24 ` Miklos Szeredi
2020-11-11 22:09 ` Vivek Goyal
2020-11-11 19:16 ` Vivek Goyal [this message]
2020-10-09 18:15 ` [PATCH v3 4/6] fuse: Don't send ATTR_MODE to kill suid/sgid for handle_killpriv_v2 Vivek Goyal
2020-10-09 18:15 ` [PATCH v3 5/6] fuse: Add a flag FUSE_OPEN_KILL_PRIV for open() request Vivek Goyal
2020-11-06 13:55 ` Miklos Szeredi
2020-11-06 16:00 ` Vivek Goyal
2020-11-06 16:33 ` Miklos Szeredi
2020-11-06 18:41 ` Vivek Goyal
2020-10-09 18:15 ` [PATCH v3 6/6] fuse: Support SB_NOSEC flag to improve direct write performance Vivek Goyal
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