linux-kernel - Re: [PATCH] ptrace: make former thread ID available via PTRACE_GETEVENTMSG after PTRACE_EVENT

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110627151827.GA6223@redhat.com>
Date:	Mon, 27 Jun 2011 17:18:27 +0200
From:	Oleg Nesterov <oleg@...hat.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	Denys Vlasenko <vda.linux@...glemail.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] ptrace: make former thread ID available via
	PTRACE_GETEVENTMSG after PTRACE_EVENT_EXEC stop (v.2)

On 06/27, Tejun Heo wrote:
>
> Hello, Oleg.
>
> On Mon, Jun 27, 2011 at 03:47:13PM +0200, Oleg Nesterov wrote:
> > > Do we want to enable this silently?  Wouldn't it be better to make it
> > > dependent on PT_SEIZED?
> >
> > Hmm. Not sure I understand. Why can't PTRACE_SEIZE add PT_TRACE_EXEC
> > (and PT_TRACESYSGOOD) along with PT_SEIZED during attach?
>
> I'm worrying about !PT_SEIZED case.  If we make it solely depend on
> PT_TRACE_EXEC, newer kernels report the old pid while olders ones
> don't

Ah, understood. So you think that the old pid should be only reported
if PT_SEIZED.

May be... Denys, what do you think?

OTOH, it looks simpler if PT_TRACE_EXEC always reports the old pid,
this can't break the applications which do not know about this new
feature.

> and the only way to discover would be either comparing kernel
> version or actually trying it - both aren't too nice.

Fortunately, currently tracehook_report_exec() zeroes ->ptrace_message.
At least this means that anything != 0 means it works.

Oleg.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/