linux-kernel - Re: [PATCH v2 02/30] fuse: Clear setuid bit even in cache=never path

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Date:   Mon, 20 May 2019 21:25:49 +0100
From:   Nikolaus Rath <Nikolaus@...h.org>
To:     Miklos Szeredi <miklos@...redi.hu>
Cc:     Vivek Goyal <vgoyal@...hat.com>, linux-fsdevel@...r.kernel.org,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        linux-nvdimm@...ts.01.org, stefanha@...hat.com,
        dgilbert@...hat.com, swhiteho@...hat.com
Subject: Re: [PATCH v2 02/30] fuse: Clear setuid bit even in cache=never path

On May 20 2019, Miklos Szeredi <miklos@...redi.hu> wrote:
> On Mon, May 20, 2019 at 04:41:37PM +0200, Miklos Szeredi wrote:
>> On Wed, May 15, 2019 at 03:26:47PM -0400, Vivek Goyal wrote:
>> > If fuse daemon is started with cache=never, fuse falls back to direct IO.
>> > In that write path we don't call file_remove_privs() and that means setuid
>> > bit is not cleared if unpriviliged user writes to a file with setuid bit set.
>> > 
>> > pjdfstest chmod test 12.t tests this and fails.
>> 
>> I think better sulution is to tell the server if the suid bit needs to be
>> removed, so it can do so in a race free way.
>> 
>> Here's the kernel patch, and I'll reply with the libfuse patch.
>
> Here are the patches for libfuse and passthrough_ll.

Could you also submit them as pull requests at https://github.com/libfuse/libfuse/pulls?

Best,
-Nikolaus

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