From: =?UTF-8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh@amazon.de>
Date: Thu, 7 Sep 2017 19:02:48 +0100
Subject: KVM: Don't accept obviously wrong gsi values via KVM_IRQFD
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Patch-mainline: v4.14-rc1
Git-commit: 36ae3c0a36b7456432fedce38ae2f7bd3e01a563
References: bsc#1077761

We cannot add routes for gsi values >= KVM_MAX_IRQ_ROUTES -- see
kvm_set_irq_routing(). Hence, there is no sense in accepting them
via KVM_IRQFD. Prevent them from entering the system in the first
place.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Acked-by: Alexander Graf <agraf@suse.de>
---
 virt/kvm/eventfd.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -565,6 +565,8 @@
 {
 	if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
 		return -EINVAL;
+	if (args->gsi >= KVM_MAX_IRQ_ROUTES)
+		return -EINVAL;
 
 	if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
 		return kvm_irqfd_deassign(kvm, args);