Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758286Ab3EDIWB (ORCPT ); Sat, 4 May 2013 04:22:01 -0400 Received: from terminus.zytor.com ([198.137.202.10]:52724 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750705Ab3EDIV7 (ORCPT ); Sat, 4 May 2013 04:21:59 -0400 Date: Sat, 4 May 2013 01:21:45 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@kernel.org, a.p.zijlstra@chello.nl, stable@kernel.org, ak@linux.intel.com, tglx@linutronix.de Reply-To: mingo@kernel.org, hpa@zytor.com, linux-kernel@vger.kernel.org, a.p.zijlstra@chello.nl, stable@kernel.org, ak@linux.intel.com, tglx@linutronix.de In-Reply-To: <20130503121256.158211806@chello.nl> References: <20130503121256.158211806@chello.nl> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf/x86/intel/lbr: Fix LBR filter Git-Commit-ID: 6e15eb3ba6c0249c9e8c783517d131b47db995ca X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2098 Lines: 57 Commit-ID: 6e15eb3ba6c0249c9e8c783517d131b47db995ca Gitweb: http://git.kernel.org/tip/6e15eb3ba6c0249c9e8c783517d131b47db995ca Author: Peter Zijlstra AuthorDate: Fri, 3 May 2013 14:11:24 +0200 Committer: Ingo Molnar CommitDate: Sat, 4 May 2013 08:37:47 +0200 perf/x86/intel/lbr: Fix LBR filter The LBR 'from' adddress is under full userspace control; ensure we validate it before reading from it. Note: is_module_text_address() can potentially be quite expensive; for those running into that with high overhead in modules optimize it using an RCU backed rb-tree. Reported-by: Andi Kleen Signed-off-by: Peter Zijlstra Cc: Cc: eranian@google.com Link: http://lkml.kernel.org/r/20130503121256.158211806@chello.nl Signed-off-by: Ingo Molnar Link: http://lkml.kernel.org/n/tip-mk8i82ffzax01cnqo829iy1q@git.kernel.org --- arch/x86/kernel/cpu/perf_event_intel_lbr.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c index da02e9c..de341d4 100644 --- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c +++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c @@ -442,8 +442,18 @@ static int branch_type(unsigned long from, unsigned long to) return X86_BR_NONE; addr = buf; - } else - addr = (void *)from; + } else { + /* + * The LBR logs any address in the IP, even if the IP just + * faulted. This means userspace can control the from address. + * Ensure we don't blindy read any address by validating it is + * a known text address. + */ + if (kernel_text_address(from)) + addr = (void *)from; + else + return X86_BR_NONE; + } /* * decoder needs to know the ABI especially -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/