[3.13.y-ckt stable] Patch "kvm: x86: fix kvm_apic_has_events to check for NULL pointer" has been added to staging queue

[Kamal Mostafa]

This is a note to let you know that I have just added a patch titled

    kvm: x86: fix kvm_apic_has_events to check for NULL pointer

to the linux-3.13.y-queue branch of the 3.13.y-ckt extended stable tree 
which can be found at:

    http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.13.y-queue

This patch is scheduled to be released in version 3.13.11-ckt23.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.13.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From c6df12c3b9f001b78508c5bbf89d8547cf2f714f Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini at redhat.com>
Date: Sat, 30 May 2015 14:31:24 +0200
Subject: kvm: x86: fix kvm_apic_has_events to check for NULL pointer

commit ce40cd3fc7fa40a6119e5fe6c0f2bc0eb4541009 upstream.

Malicious (or egregiously buggy) userspace can trigger it, but it
should never happen in normal operation.

Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
Reference: CVE-2015-4692
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 arch/x86/kvm/lapic.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index c8b0d0d..fc87568 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -165,7 +165,7 @@ static inline u16 apic_logical_id(struct kvm_apic_map *map, u32 ldr)

 static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
 {
-	return vcpu->arch.apic->pending_events;
+	return kvm_vcpu_has_lapic(vcpu) && vcpu->arch.apic->pending_events;
 }

 bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
--
1.9.1