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authorAndy Honig <ahonig@google.com>2014-08-27 21:42:54 (GMT)
committerPaolo Bonzini <pbonzini@redhat.com>2014-10-24 11:21:14 (GMT)
commit2febc839133280d5a5e8e1179c94ea674489dae2 (patch)
tree4c3f4f0ab1273a88cd7edf639c944ad4212a13c0
parent8b3c3104c3f4f706e99365c3e0d2aa61b95f969f (diff)
downloadlinux-2febc839133280d5a5e8e1179c94ea674489dae2.tar.xz
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>
-rw-r--r--arch/x86/kvm/i8254.c2
1 files changed, 2 insertions, 0 deletions
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)