Patch "perf/x86/intel/lbr: Fix LBR filter" has been added to the 3.8-stable tree

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



This is a note to let you know that I've just added the patch titled

    perf/x86/intel/lbr: Fix LBR filter

to the 3.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     perf-x86-intel-lbr-fix-lbr-filter.patch
and it can be found in the queue-3.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.


>From 6e15eb3ba6c0249c9e8c783517d131b47db995ca Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Date: Fri, 3 May 2013 14:11:24 +0200
Subject: perf/x86/intel/lbr: Fix LBR filter

From: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>

commit 6e15eb3ba6c0249c9e8c783517d131b47db995ca upstream.

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 <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: eranian@xxxxxxxxxx
Link: http://lkml.kernel.org/r/20130503121256.158211806@xxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: http://lkml.kernel.org/n/tip-mk8i82ffzax01cnqo829iy1q@xxxxxxxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 arch/x86/kernel/cpu/perf_event_intel_lbr.c |   14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

--- 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 fro
 			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


Patches currently in stable-queue which might be from a.p.zijlstra@xxxxxxxxx are

queue-3.8/perf-x86-intel-add-support-for-ivybridge-model-58-uncore.patch
queue-3.8/perf-x86-intel-fix-unintended-variable-name-reuse.patch
queue-3.8/perf-x86-intel-lbr-demand-proper-privileges-for-perf_sample_branch_kernel.patch
queue-3.8/perf-x86-intel-lbr-fix-lbr-filter.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [Linux Kernel]     [Kernel Development Newbies]     [Linux USB Devel]     [Video for Linux]     [Linux Audio Users]     [Yosemite Hiking]     [Linux Kernel]     [Linux SCSI]