kernel/KVM-x86-Improve-thread-safety-in-pit.patch
Josh Boyer 4ac9db0e26 CVE-2014-3610 kvm: noncanonical MSR writes (rhbz 1144883 1156543)
- CVE-2014-3611 kvm: PIT timer race condition (rhbz 1144878 1156537)
- CVE-2014-3646 kvm: vmx: invvpid vm exit not handled (rhbz 1144825 1156534)
- CVE-2014-8369 kvm: excessive pages un-pinning in kvm_iommu_map error path (rhbz 1156518 1156522)
- CVE-2014-8480 CVE-2014-8481 kvm: NULL pointer dereference during rip relative instruction emulation (rhbz 1156615 1156616)
2014-10-24 20:14:02 -04:00

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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