linux-kernel - Re: [PATCH] Add a sysctl option to disable bpf offensive helpers.

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Message-ID: <ZIackaLpA3APFFvj@infradead.org>
Date:   Sun, 11 Jun 2023 21:18:25 -0700
From:   Christoph Hellwig <hch@...radead.org>
To:     Yi He <clangllvm@....com>
Cc:     ast@...nel.org, daniel@...earbox.net, andrii@...nel.org,
        song@...nel.org, yhs@...com, john.fastabend@...il.com,
        kpsingh@...nel.org, sdf@...gle.com, haoluo@...gle.com,
        jolsa@...nel.org, rostedt@...dmis.org, mhiramat@...nel.org,
        davem@...emloft.net, kuba@...nel.org, hawk@...nel.org,
        linux-kernel@...r.kernel.org, linux-trace-kernel@...r.kernel.org,
        netdev@...r.kernel.org, bpf@...r.kernel.org,
        linux-security-module@...r.kernel.org
Subject: Re: [PATCH] Add a sysctl option to disable bpf offensive helpers.

On Sat, Jun 10, 2023 at 03:26:18PM +0000, Yi He wrote:
> The default value of sysctl_offensive_bpf_disabled is 0, which means 
> all the five helpers are enabled. By setting sysctl_offensive_bpf_disabled 
> to 1, these helpers cannot be used util a reboot. By setting it to 2, 
> these helpers cannot be used but privieleged users can modify this flag
> to 0.

That's just a nightmare API.  The right thing is to not allow
program types that can use the helpers from anything but a global
fully privileged context.

And offensive is in this context a really weird term.  Nothing is
offensive here, invasive or allowing to change kernel state might be
better terms.