linux-kernel - Re: [PATCH] fuse:rely on fuse_perm for exec when no mode bits set

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Message-ID: <CAJfpegvWBHootLiE_zsw35G6Ee387V=Da_wCzaV9NhZQVDKYGg@mail.gmail.com>
Date:   Tue, 28 Apr 2020 10:21:01 +0200
From:   Miklos Szeredi <miklos@...redi.hu>
To:     Chakra Divi <chakragithub@...il.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fuse:rely on fuse_perm for exec when no mode bits set

On Mon, Apr 27, 2020 at 3:46 PM Chakra Divi <chakragithub@...il.com> wrote:
>
> On Tue, Apr 21, 2020 at 4:21 PM Chakra Divi <chakragithub@...il.com> wrote:
> >
> > On Mon, Apr 20, 2020 at 4:55 PM Miklos Szeredi <miklos@...redi.hu> wrote:
> > >
> > > On Wed, Apr 1, 2020 at 11:31 AM Chakra Divi <chakragithub@...il.com> wrote:
> > > >
> > > > In current code, for exec we are checking mode bits
> > > > for x bit set even though the fuse_perm_getattr returns
> > > > success. Changes in this patch avoids mode bit explicit
> > > > check, leaves the exec checking to fuse file system
> > > > in uspace.
> > >
> > > Why is this needed?
> >
> > Thanks for responding Miklos. We have an use case with our remote file
> > system mounted on fuse , where permissions checks will happen remotely
> > without the need of mode bits. In case of read, write it worked
> > without issues. But for executable files, we found that fuse kernel is
> > explicitly checking 'x' mode bit set on the file. We want this
> > checking also to be pushed to remote instead of kernel doing it - so
> > modified the kernel code to send getattr op to usespace in exec case
> > too.
>
> Any help on this Miklos....

I still don't understand what you are requesting.  What your patch
does is unconditionally allow execution, even without any 'x' bits in
the mode.  What does that achieve?

Thanks,
Miklos