linux-kernel - [PATCH 08/32] perf, x86: Disable LBR recording for unknown LBR

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,  9 Nov 2012 17:27:24 -0800
From:	Andi Kleen <andi@...stfloor.org>
To:	linux-kernel@...r.kernel.org
Cc:	acme@...hat.com, peterz@...radead.org, jolsa@...hat.com,
	eranian@...gle.com, mingo@...nel.org, namhyung@...nel.org,
	Andi Kleen <ak@...ux.intel.com>
Subject: [PATCH 08/32] perf, x86: Disable LBR recording for unknown LBR_FMT

From: Andi Kleen <ak@...ux.intel.com>

When the LBR format is unknown disable LBR recording. This prevents
crashes when the LBR address is misdecoded and mis-sign extended.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
---
 arch/x86/kernel/cpu/perf_event_intel_lbr.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/arch/x86/kernel/cpu/perf_event_intel_lbr.c b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
index 2af6695b..ad5af13 100644
--- a/arch/x86/kernel/cpu/perf_event_intel_lbr.c
+++ b/arch/x86/kernel/cpu/perf_event_intel_lbr.c
@@ -13,6 +13,7 @@ enum {
 	LBR_FORMAT_EIP		= 0x02,
 	LBR_FORMAT_EIP_FLAGS	= 0x03,
 	LBR_FORMAT_EIP_FLAGS2	= 0x04,
+	LBR_FORMAT_MAX_KNOWN	= LBR_FORMAT_EIP_FLAGS2,
 };
 
 /*
@@ -392,7 +393,7 @@ int intel_pmu_setup_lbr_filter(struct perf_event *event)
 	/*
 	 * no LBR on this PMU
 	 */
-	if (!x86_pmu.lbr_nr)
+	if (!x86_pmu.lbr_nr || x86_pmu.intel_cap.lbr_format > LBR_FORMAT_MAX_KNOWN)
 		return -EOPNOTSUPP;
 
 	/*
-- 
1.7.7.6

--
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/