From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael Kerrisk (man-pages)" Subject: Re: Documenting ptrace access mode checking Date: Thu, 23 Jun 2016 09:06:55 +0200 Message-ID: References: <87ziqewc3r.fsf@x220.int.ebiederm.org> <20160622215142.GA14751@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160622215142.GA14751-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-api-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Oleg Nesterov , "Eric W. Biederman" Cc: mtk.manpages-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, Jann Horn , James Morris , linux-man , Stephen Smalley , lkml , Kees Cook , linux-security-module , Linux API List-Id: linux-man@vger.kernel.org Hi Oleg, On 06/22/2016 11:51 PM, Oleg Nesterov wrote: > On 06/21, Eric W. Biederman wrote: >> >> Adding Oleg just because he seems to do most of the ptrace related >> maintenance these days. > > so I have to admit that I never even tried to actually understand > ptrace_may_access ;) > >> We certainly need something that gives a high level view so people >> reading the man page can know what to expect. If you get down into the >> weeds we run the danger of people beginning to think they can depend >> upon bugs in the implementation. > > Personally I agree. I think "man ptrace" shouldn't not tell too much > about kernel internals. See my other replies on this topic. Somehow, we need a way of describing the behavior that user-space sees. I think it's inevitable that that means talking about what;s going on "under the hood". Regarding Eric's point that "we run the danger of people beginning to think they can depend upon bugs in the implementation": when it comes to breaking the ABI, the presence or absence of documentation doesn't save us on that point (Linus has a few times made his position wrt to documentation clear). Cheers, Michael -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/