linux-kernel - Re: [PATCH 01/10] perf,x86: Fix event/group validation

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, 21 Aug 2015 16:31:28 -0400
From:	Sasha Levin <sasha.levin@...cle.com>
To:	Peter Zijlstra <peterz@...radead.org>, mingo@...nel.org
CC:	vincent.weaver@...ne.edu, eranian@...gle.com, jolsa@...hat.com,
	kan.liang@...el.com, linux-kernel@...r.kernel.org,
	Andrew Hunter <ahh@...gle.com>,
	Maria Dimakopoulou <maria.n.dimakopoulou@...il.com>
Subject: Re: [PATCH 01/10] perf,x86: Fix event/group validation

On 05/21/2015 07:17 AM, Peter Zijlstra wrote:
> --- a/arch/x86/kernel/cpu/perf_event_intel.c
> +++ b/arch/x86/kernel/cpu/perf_event_intel.c
> @@ -2106,7 +2106,7 @@ static struct event_constraint *
>  intel_get_event_constraints(struct cpu_hw_events *cpuc, int idx,
>  			    struct perf_event *event)
>  {
> -	struct event_constraint *c1 = event->hw.constraint;
> +	struct event_constraint *c1 = cpuc->event_constraint[idx];
>  	struct event_constraint *c2;

Hey Peter,

I was chasing a memory corruption in this area and I think I found
a possible culprit:

After this patch, In the code above, we'd access "cpuc->event_constraint[idx]"
and read/change memory.

The problem is that a valid value for idx is also -1, which isn't checked
here, so we end up accessing and possibly corrupting memory that isn't ours.


Thanks,
Sasha
--
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/