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Message-ID: <be02c1974b028efcc2a0ec49dfedff456a78e156.camel@corsac.net>
Subject: Re: [PATCH] yama: clarify ptrace_scope=2 in Yama documentation
From:   Yves-Alexis Perez <corsac@corsac.net>
To:     Matthew Wilcox <willy@infradead.org>
Cc:     Kees Cook <keescook@chromium.org>,
        Jonathan Corbet <corbet@lwn.net>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, trivial@kernel.org
Date:   Tue, 02 Oct 2018 23:08:34 +0200
In-Reply-To: <20181002205259.GA16090@bombadil.infradead.org>
References: <20181002204722.GA9610@scapa.corsac.net>
         <20181002205259.GA16090@bombadil.infradead.org>
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On Tue, 2018-10-02 at 13:52 -0700, Matthew Wilcox wrote:
> On Tue, Oct 02, 2018 at 10:47:23PM +0200, Yves-Alexis Perez wrote:
> > Current phrasing is ambiguous since it's unclear if attaching to a
> > children through PTRACE_TRACEME requires CAP_SYS_PTRACE. Rephrase the
> > sentence to make that clear.
> 
> I disagree that your sentence makes that clear.  How about:
> 
> >  2 - admin-only attach:
> > -    only processes with ``CAP_SYS_PTRACE`` may use ptrace
> > -    with ``PTRACE_ATTACH``, or through children calling
> > ``PTRACE_TRACEME``.
> > +    only processes with ``CAP_SYS_PTRACE`` may use ptrace, either with
> > +    ``PTRACE_ATTACH`` or through children calling ``PTRACE_TRACEME``.
> 
> +    only processes with ``CAP_SYS_PTRACE`` may use ptrace.  This
> +    restricts both ``PTRACE_ATTACH`` and ``PTRACE_TRACEME``.

Hi Matthew,

I'm no native speaker, both versions are fine by me but I liked keeping the
“children calling” part since the semantics are quite different for
PTRACE_ATTACH and PTRACE_TRACEME.

Regards,
-- 
Yves-Alexis