This is a note to let you know that I've just added the patch titled
KVM: x86: Improve thread safety in pit
to the 3.14-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:
kvm-x86-improve-thread-safety-in-pit.patch
and it can be found in the queue-3.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2febc839133280d5a5e8e1179c94ea674489dae2 Mon Sep 17 00:00:00 2001
From: Andy Honig <ahonig@xxxxxxxxxx>
Date: Wed, 27 Aug 2014 14:42:54 -0700
Subject: KVM: x86: Improve thread safety in pit
From: Andy Honig <ahonig@xxxxxxxxxx>
commit 2febc839133280d5a5e8e1179c94ea674489dae2 upstream.
There's a race condition in the PIT emulation code in KVM. In
__kvm_migrate_pit_timer the pit_timer object is accessed without
synchronization. If the race condition occurs at the wrong time this
can crash the host kernel.
This fixes CVE-2014-3611.
Signed-off-by: Andrew Honig <ahonig@xxxxxxxxxx>
Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/x86/kvm/i8254.c | 2 ++
1 file changed, 2 insertions(+)
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -262,8 +262,10 @@ void __kvm_migrate_pit_timer(struct kvm_
return;
timer = &pit->pit_state.timer;
+ mutex_lock(&pit->pit_state.lock);
if (hrtimer_cancel(timer))
hrtimer_start_expires(timer, HRTIMER_MODE_ABS);
+ mutex_unlock(&pit->pit_state.lock);
}
static void destroy_pit_timer(struct kvm_pit *pit)
Patches currently in stable-queue which might be from ahonig@xxxxxxxxxx are
queue-3.14/kvm-x86-prevent-host-from-panicking-on-shared-msr-writes.patch
queue-3.14/kvm-x86-improve-thread-safety-in-pit.patch
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