linux-kernel - Re: [PATCH 2/5] ptrace: implement PTRACE

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: <201106181057.02477.vda.linux@googlemail.com>
Date:	Sat, 18 Jun 2011 10:57:02 +0200
From:	Denys Vlasenko <vda.linux@...glemail.com>
To:	Tejun Heo <tj@...nel.org>
Cc:	oleg@...hat.com, jan.kratochvil@...hat.com,
	linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
	akpm@...ux-foundation.org, indan@....nu, bdonlan@...il.com,
	pedro@...esourcery.com
Subject: Re: [PATCH 2/5] ptrace: implement PTRACE_SEIZE

On Saturday 18 June 2011 10:35, Tejun Heo wrote:
> Hello,
> 
> On Sat, Jun 18, 2011 at 09:59:38AM +0200, Denys Vlasenko wrote:
> > ...unless we plan to introduce PTRACE_O_TRACESTOP (with value 0x00000080)
> > which enables PTRACE_INTERRUPT and stop notifications independently
> > of PTRACE_SEIZE. Which would be very useful for e.g. strace.
> 
> I know you're a big fan of those option flags but I don't really see
> the added value in making these behaviors optional rather than keeping
> things backward compatible - ie. introducing new event needed to be
> gated somehow so the O flags but SEIZE itself serves as a big gate
> anyway so I don't see much point in introducing multiple selectable
> behaviors.  It's not like PTRACE_O_TRACESTOP is gonna make anything
> drastically easier or reduce significant amount of overhead.

I explained this already. strace code is a bit complex, and adding
more complexity so that it uses PTRACE_SEIZE if available, but PTRACE_ATTACH
if it is not, will add some PITA.

Considering that strace does not want PTRACE_SEIZE per se, it only wants
to have a way to properly see and handle group stops, having an option
to enable *only that functonality* without having to use PTRACE_SEIZE
will be useful for strace.

-- 
vda
--
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/