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

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Ian Campbell <ian.campbell@xxxxxxxxxx>
# Date 1358938044 -3600
# Node ID 621b1a889e9b120236698731e0b5ecc5b0cb1d82
# Parent  9efe4c0bf9c8d3ecf03868c69c24dad3218523a4
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>
Committed-by: Jan Beulich <jbeulich@xxxxxxxx>
---


diff -r 9efe4c0bf9c8 -r 621b1a889e9b xen/arch/x86/hvm/hvm.c
--- a/xen/arch/x86/hvm/hvm.c    Wed Jan 23 10:31:04 2013 +0100
+++ b/xen/arch/x86/hvm/hvm.c    Wed Jan 23 11:47:24 2013 +0100
@@ -3881,6 +3881,11 @@ long do_hvm_op(unsigned long op, XEN_GUE
                     rc = -EINVAL;
                 break;
             case HVM_PARAM_NESTEDHVM:
+                if ( !IS_PRIV(current->domain) )
+                {
+                    rc = -EPERM;
+                    break;
+                }
                 if ( a.value > 1 )
                     rc = -EINVAL;
                 if ( !is_hvm_domain(d) )

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