37 lines
1.0 KiB
Diff
37 lines
1.0 KiB
Diff
|
From: Andy Honig <ahonig@google.com>
|
||
|
|
Date: Fri, 24 Oct 2014 17:07:14 +0200
|
||
|
|
Subject: [PATCH] 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.
|
||
|
|
|
||
|
|
This fixes CVE-2014-3611.
|
||
|
|
|
||
|
|
Cc: stable@vger.kernel.org
|
||
|
|
Signed-off-by: Andrew Honig <ahonig@google.com>
|
||
|
|
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
|
||
|
|
---
|
||
|
|
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 518d86471b76..298781d4cfb4 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)
|
||
|
|
--
|
||
|
|
1.9.3
|
||
|
|
|