Patchwork [2/2,Lucid,CVE-2012-2137] KVM: Fix buffer overflow in kvm_set_irq()

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Submitter Tim Gardner
Date Sept. 6, 2012, 9:06 p.m.
Message ID <1346965615-44004-2-git-send-email-tim.gardner@canonical.com>
Download mbox | patch
Permalink /patch/182280/
State New
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Comments

Tim Gardner - Sept. 6, 2012, 9:06 p.m.
From: Avi Kivity <avi@redhat.com>

CVE-2012-2137

BugLink: http://bugs.launchpad.net/bugs/1016298

kvm_set_irq() has an internal buffer of three irq routing entries, allowing
connecting a GSI to three IRQ chips or on MSI.  However setup_routing_entry()
does not properly enforce this, allowing three irqchip routes followed by
an MSI route to overflow the buffer.

Fix by ensuring that an MSI entry is added to an empty list.

Signed-off-by: Avi Kivity <avi@redhat.com>
(cherry picked from commit f2ebd422f71cda9c791f76f85d2ca102ae34a1ed)

Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
---
 virt/kvm/irq_comm.c |    1 +
 1 file changed, 1 insertion(+)
Stefan Bader - Sept. 7, 2012, 10:11 a.m.
On 06.09.2012 23:06, Tim Gardner wrote:
> From: Avi Kivity <avi@redhat.com>
> 
> CVE-2012-2137
> 
> BugLink: http://bugs.launchpad.net/bugs/1016298
> 
> kvm_set_irq() has an internal buffer of three irq routing entries, allowing
> connecting a GSI to three IRQ chips or on MSI.  However setup_routing_entry()
> does not properly enforce this, allowing three irqchip routes followed by
> an MSI route to overflow the buffer.
> 
> Fix by ensuring that an MSI entry is added to an empty list.
> 
> Signed-off-by: Avi Kivity <avi@redhat.com>
> (cherry picked from commit f2ebd422f71cda9c791f76f85d2ca102ae34a1ed)
> 
> Signed-off-by: Tim Gardner <tim.gardner@canonical.com>
> ---
>  virt/kvm/irq_comm.c |    1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
> index 40935be..5494097 100644
> --- a/virt/kvm/irq_comm.c
> +++ b/virt/kvm/irq_comm.c
> @@ -300,6 +300,7 @@ static int setup_routing_entry(struct kvm_irq_routing_table *rt,
>  	 */
>  	hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
>  		if (ei->type == KVM_IRQ_ROUTING_MSI ||
> +		    ue->type == KVM_IRQ_ROUTING_MSI ||
>  		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
>  			return r;
>  
>

Patch

diff --git a/virt/kvm/irq_comm.c b/virt/kvm/irq_comm.c
index 40935be..5494097 100644
--- a/virt/kvm/irq_comm.c
+++ b/virt/kvm/irq_comm.c
@@ -300,6 +300,7 @@  static int setup_routing_entry(struct kvm_irq_routing_table *rt,
 	 */
 	hlist_for_each_entry(ei, n, &rt->map[ue->gsi], link)
 		if (ei->type == KVM_IRQ_ROUTING_MSI ||
+		    ue->type == KVM_IRQ_ROUTING_MSI ||
 		    ue->u.irqchip.irqchip == ei->irqchip.irqchip)
 			return r;