linux-kernel - Re: [PATCH v5 12/20] x86: perf: intel

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: <8738ad3nx6.fsf@ashishki-desk.ger.corp.intel.com>
Date:	Fri, 24 Oct 2014 10:52:05 +0300
From:	Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:	Peter Zijlstra <peterz@...radead.org>
Cc:	Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
	Robert Richter <rric@...nel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Mike Galbraith <efault@....de>,
	Paul Mackerras <paulus@...ba.org>,
	Stephane Eranian <eranian@...gle.com>,
	Andi Kleen <ak@...ux.intel.com>, kan.liang@...el.com,
	adrian.hunter@...el.com, acme@...radead.org
Subject: Re: [PATCH v5 12/20] x86: perf: intel_pt: Intel PT PMU driver

Peter Zijlstra <peterz@...radead.org> writes:

> On Mon, Oct 13, 2014 at 04:45:40PM +0300, Alexander Shishkin wrote:
>> +static bool pt_event_valid(struct perf_event *event)
>> +{
>> +	u64 config = event->attr.config;
>> +
>> +	/* admin can set any packet generation parameters */
>> +	if (capable(CAP_SYS_ADMIN) && (config & PT_BYPASS_MASK) == config)
>> +		return true;
>> +
>> +	if ((config & PT_CONFIG_MASK) != config)
>> +		return false;
>> +
>> +	return true;
>> +}
>
> This seems to suggest PT is available to !priv users, is this right?

Yes, that's the intention. PT does CPL-based filtering in hardware and
unlike previous attempts at branch tracing, does not leak out-of-context
addresses (or any other information for that matter).

Regards,
--
Alex
--
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/