Re: [PATCH] tools lib traceevent: Fix buffer overflow in arg_eval

From: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
To: Steven Rostedt <rostedt@goodmis.org>
Cc: Tony Jones <tonyj@suse.de>,
	linux-kernel@vger.kernel.org,
	Arnaldo Carvalho de Melo <acme@redhat.com>,
	linux-perf-users@vger.kernel.org,
	Mathias Krause <minipli@googlemail.com>,
	linux-trace-devel@vger.kernel.org,
	Tzvetomir Stoyanov <tstoyanov@vmware.com>,
	Michael Sartain <mikesart@fastmail.com>
Subject: Re: [PATCH] tools lib traceevent: Fix buffer overflow in arg_eval
Date: Thu, 28 Feb 2019 16:01:23 -0300	[thread overview]
Message-ID: <20190228190123.GK9508@kernel.org> (raw)
In-Reply-To: <20190227221250.74996869@vmware.local.home>

Em Wed, Feb 27, 2019 at 10:12:50PM -0500, Steven Rostedt escreveu:
> On Wed, 27 Feb 2019 17:55:32 -0800
> Tony Jones <tonyj@suse.de> wrote:
> 
> > Fix buffer overflow observed when running perf test.
> > 
> > The overflow is when trying to evaluate "1ULL << (64 - 1)" which
> > is resulting in -9223372036854775808 which overflows the 20 character
> > buffer.
> > 
> > If is possible this bug has been reported before but I still don't
> > see any fix checked in:
> > 
> > See: https://www.spinics.net/lists/linux-perf-users/msg07714.html
> > 
> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > Cc: linux-perf-users@vger.kernel.org
> > Cc: Steven Rostedt <rostedt@goodmis.org>
> > Signed-off-by: Tony Jones <tonyj@suse.de>
> 
> Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
> 
> I have to say I've let this slide and it is not the first time a patch
> went out with this fix. But this one has the correct fix because we
> should use a buffer with a multiple of 4. Anyway, Tony I believe was
> the first to report this anyway.
> 
> For reference we have:
> 
> I first heard about Tony's complaint on a post to linux-perf-users on Jan 18.
> 
> But then we had after that:
> 
>  Michael Sartain reported it on 1/24 (and fixed by Tzvetomir)
>  https://lore.kernel.org/linux-trace-devel/20190125102014.19600-1-tstoyanov@vmware.com/
>  
> It was later fixed again by Mathias Krause
>  https://lore.kernel.org/linux-trace-devel/20190223122404.21137-1-minipli@googlemail.com/
> 
> But since Tony was first to report it, and we discussed that it should
> be 24 bytes, I would say this is the patch to take.
> 
> Again, sorry for not getting this acknowledged earlier and everyone doing
> the same thing multiple times. :-/
> 
> Arnaldo, please take this patch. But also add:
> 
> Reported-by: Michael Sartain <mikesart@fastmail.com>
> Reported-by: Mathias Krause <minipli@googlemail.com>

Will do.

Thanks for the credit research,

- Arnaldo