[PATCH 0/2] perf/x86/intel: Work around BTS leaking kernel addresses

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From	Alexander Shishkin <alexander.shishkin@linux.intel.com>
Newsgroups	linux.kernel
Subject	[PATCH 0/2] perf/x86/intel: Work around BTS leaking kernel addresses
Date	Thu, 27 Aug 2015 17:20:02 +0200
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X-Original-To	Peter Zijlstra <a.p.zijlstra@chello.nl>
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X-Original-Cc	Ingo Molnar <mingo@redhat.com>, linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo <acme@infradead.org>, Alexander Shishkin <alexander.shishkin@linux.intel.com>
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Hi Peter,

Due to imprecise IP sampling, BTS may (and often does) leak kernel
addresses when kernel tracing is not even enabled, which results in
mostly syscall entry points and page_fault handler addresses being
exposed. This might be a security concern for the address
randomization, and it also makes life harder for gdb that makes use of
bts samples.

This patchset works around the old (DS) driver and disables the new
(intel_bts) for the unprivileged users on systems where perf paranoia
level prohibits kernel tracing.

Not sure if these should be treated as bugfixes.

Alexander Shishkin (2):
  perf/x86/intel/ds: Work around BTS leaking kernel addresses
  perf/x86/intel/bts: Disallow use by unprivileged users on paranoid
    systems

 arch/x86/kernel/cpu/perf_event_intel_bts.c | 10 ++++++++
 arch/x86/kernel/cpu/perf_event_intel_ds.c  | 40 +++++++++++++++++++++++++-----
 2 files changed, 44 insertions(+), 6 deletions(-)

-- 
2.5.0

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[PATCH 0/2] perf/x86/intel: Work around BTS leaking kernel addresses Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2015-08-27 17:20 +0200

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