[Xen-changelog] [xen-4.2-testing] xen: Do not allow guests to enable nested HVM on themselves

[Xen patchbot-4.2-testing <patchbot@xxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1358938364 -3600
# Node ID 7c04074a0a0f897f6745fb3328746bc50bb91d71
# Parent  fef7ef92f08e46d6f7b04551394d17a835dbe110
xen: Do not allow guests to enable nested HVM on themselves

There is no reason for this and doing so exposes a memory leak to
guests. Only toolstacks need write access to this HVM param.

This is XSA-35 / CVE-2013-0152.

Signed-off-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
Acked-by: Jan Beulich <JBeulich@xxxxxxxx>
xen-unstable changeset: 26444:621b1a889e9b
xen-unstable date: Wed Jan 23 10:47:24 UTC 2013
---


diff -r fef7ef92f08e -r 7c04074a0a0f xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Wed Jan 23 11:51:16 2013 +0100
+++ b/xen/arch/x86/hvm/hvm.c    Wed Jan 23 11:52:44 2013 +0100
@@ -3862,6 +3862,11 @@ long do_hvm_op(unsigned long op, XEN_GUE
                     rc = -EINVAL;
                 break;
             case HVM_PARAM_NESTEDHVM:
+                if ( !IS_PRIV(current->domain) )
+                {
+                    rc = -EPERM;
+                    break;
+                }
 #ifdef __i386__
                 if ( a.value )
                     rc = -EINVAL;

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