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Subject: Re: [PATCH V9 2/4] fuse: Trace daemon creds
To:     Miklos Szeredi <miklos@szeredi.hu>,
        Alessio Balsini <balsini@android.com>
Cc:     Akilesh Kailash <akailash@google.com>,
        Amir Goldstein <amir73il@gmail.com>,
        David Anderson <dvander@google.com>,
        Giuseppe Scrivano <gscrivan@redhat.com>,
        Jann Horn <jannh@google.com>, Jens Axboe <axboe@kernel.dk>,
        Martijn Coenen <maco@android.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Lawrence <paullawrence@google.com>,
        Stefano Duo <stefanoduo@google.com>,
        Zimuzo Ezeozue <zezeozue@google.com>,
        fuse-devel <fuse-devel@lists.sourceforge.net>,
        kernel-team <kernel-team@android.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
References: <20200924131318.2654747-1-balsini@android.com>
 <20200924131318.2654747-3-balsini@android.com>
 <CAJfpegvvf4MfO4Jw5A=TJJfrxN_1xFTmwBJ2bb9UfzYBgkhzzQ@mail.gmail.com>
From:   Antonio SJ Musumeci <trapexit@spawn.link>
Message-ID: <a5d94f04-a980-ee3f-bd8d-42df3a859777@spawn.link>
Date:   Wed, 30 Sep 2020 15:16:20 -0400
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On 9/30/2020 2:45 PM, Miklos Szeredi wrote:
> On Thu, Sep 24, 2020 at 3:13 PM Alessio Balsini <balsini@android.com> wrote:
>> Add a reference to the FUSE daemon credentials, so that they can be used to
>> temporarily raise the user credentials when accessing lower file system
>> files in passthrough.
> Hmm, I think it would be better to store the creds of the ioctl()
> caller together with the open file.   The mounter may deliberately
> have different privileges from the process doing the actual I/O.
>
> Thanks,
> Miklos


In my usecase I'm changing euid/egid of the thread to whichever the 
uid/gid was passed to the server which is otherwise running as root.