[patch] CVE-2014-3611.patch

CVE-2014-3611.patch (text/plain), 1.02 KB, created by Stefan Behte (RETIRED) on 2014-10-15 11:00:05 UTC

From 1c8a72a1e9a3e28245f5da862afe8850462adfd9 Mon Sep 17 00:00:00 2001
From: Andy Honig <[e-mail]>
Date: Wed, 27 Aug 2014 14:42:54 -0700
Subject: [PATCH 2/3] KVM/x86: Improve thread safety in pit

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.

Signed-off-by: Andrew Honig <[e-mail]>
---
 arch/x86/kvm/i8254.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c
index 518d864..298781d 100644
--- a/arch/x86/kvm/i8254.c
+++ b/arch/x86/kvm/i8254.c
@@ -262,8 +262,10 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu)
 		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)
-- 
2.1.0.rc2.206.gedb03e5