netdev - Re: [PATCH v5 bpf-next 03/13] bpf: introduce BPF token object

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Date: Mon, 9 Oct 2023 18:53:40 -0400
From: Paul Moore <paul@...l-moore.com>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc: Christian Brauner <brauner@...nel.org>, Andrii Nakryiko <andrii@...nel.org>, bpf@...r.kernel.org, 
	netdev@...r.kernel.org, linux-fsdevel@...r.kernel.org, 
	linux-security-module@...r.kernel.org, keescook@...omium.org, 
	lennart@...ttering.net, kernel-team@...a.com, sargun@...gun.me
Subject: Re: [PATCH v5 bpf-next 03/13] bpf: introduce BPF token object

On Wed, Sep 27, 2023 at 12:03 PM Andrii Nakryiko
<andrii.nakryiko@...il.com> wrote:
> On Wed, Sep 27, 2023 at 2:52 AM Christian Brauner <brauner@...nel.org> wrote:

...

> > IOW, everything stays the same apart from the fact that bpf token fds
> > are actually file descriptors referring to a detached bpffs file instead
> > of an anonymous inode file. IOW, bpf tokens are actual bpffs objects
> > tied to a bpffs instance.
>
> Ah, ok, this is a much smaller change than what I was about to make.
> I'm glad I asked and thanks for elaborating! I'll use
> alloc_file_pseudo() using bpffs mount in the next revision.

Just a FYI, I'm still looking at v6 now, but moving from an anon_inode
to a bpffs inode may mean we need to drop a LSM hook in
bpf_token_create() to help mark the inode as a BPF token.  Not a big
deal either way, and I think it makes sense to use a bpffs inode as
opposed to an anonymous inode, just wanted to let you know.

-- 
paul-moore.com