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 3.10-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-3.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 2febc839133280d5a5e8e1179c94ea674489dae2 Mon Sep 17 00:00:00 2001
From: Andy Honig <[email protected]>
Date: Wed, 27 Aug 2014 14:42:54 -0700
Subject: KVM: x86: Improve thread safety in pit

From: Andy Honig <[email protected]>

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 <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 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 [email protected] are

queue-3.10/kvm-x86-prevent-host-from-panicking-on-shared-msr-writes.patch
queue-3.10/kvm-x86-improve-thread-safety-in-pit.patch
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Reply via email to