linux-kernel - Re: [PATCH 03/10] 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]

Date:	Fri, 20 May 2011 11:07:18 +0200
From:	Tejun Heo <tj@...nel.org>
To:	Pedro Alves <pedro@...esourcery.com>
Cc:	Denys Vlasenko <vda.linux@...glemail.com>, 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
Subject: Re: [PATCH 03/10] ptrace: implement PTRACE_SEIZE

Hello, Pedro.

On Fri, May 20, 2011 at 12:00:17AM +0100, Pedro Alves wrote:
> > > UUIC, that opens a race where between SEIZEing and
> > > SETOPTIONS(O_TRACE FORK|VFORK|EXEC...), the tracee can
> > > fork/vfork/clone/exec, without the tracer getting the
> > > nice corresponding PTRACE_EVENT_ events.

Does it matter?  The order of execution isn't even well defined
without synchronization border.  If you want full synchronization, you
can INTERRUPT tracee.

>  SEIZE,execvd,INTERRUPT (SETOPTS on interrupt)
> 
> will make the tracer see a SIGTRAP that 
> 
>  execvd,SEIZE,INTERRUPT
> 
> nor
> 
>  SEIZE,SETOPTS,execvd (SETOPTS on interrupt)
> 
> would cause, isn't it?

Yes, SIGTRAP on exec(2) is nasty but also is scheduled to be removed
if SEIZED.

> Now, if it were possible for the tracer to set the
> default OPTS _before_ PTRACE_ATTACH/PTRACE_SEIZE...

I don't see why that would be necessary.

Thanks.

-- 
tejun
--
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/