[Xen-changelog] [xen-unstable] x86/pvhvm: properly range-check PHYSDEVOP_map_pirq/MAP_PIRQ_TYPE_GSI

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Ian Jackson <Ian.Jackson@xxxxxxxxxxxxx>
# Date 1346844592 -3600
# Node ID 2750340a347da93fa694bbbf60d71b44fe3b0ca7
# Parent  bcf58ef63b7c844fe431eb9e394fc1ea5dd437c4
x86/pvhvm: properly range-check PHYSDEVOP_map_pirq/MAP_PIRQ_TYPE_GSI

This is being used as a array index, and hence must be validated before
use.

This is XSA-16 / CVE-2012-3498.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r bcf58ef63b7c -r 2750340a347d xen/arch/x86/physdev.c
--- a/xen/arch/x86/physdev.c    Wed Sep 05 12:29:03 2012 +0100
+++ b/xen/arch/x86/physdev.c    Wed Sep 05 12:29:52 2012 +0100
@@ -42,11 +42,18 @@ static int physdev_hvm_map_pirq(
         struct hvm_girq_dpci_mapping *girq;
         uint32_t machine_gsi = 0;
 
+        if ( *index < 0 || *index >= NR_HVM_IRQS )
+        {
+            ret = -EINVAL;
+            break;
+        }
+
         /* find the machine gsi corresponding to the
          * emulated gsi */
         hvm_irq_dpci = domain_get_irq_dpci(d);
         if ( hvm_irq_dpci )
         {
+            BUILD_BUG_ON(ARRAY_SIZE(hvm_irq_dpci->girq) < NR_HVM_IRQS);
             list_for_each_entry ( girq,
                                   &hvm_irq_dpci->girq[*index],
                                   list )

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