pkgsrc-ng/sysutils/xenkernel41/patches/patch-CVE-2013-4553
2014-08-11 13:27:10 +02:00

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$NetBSD: patch-CVE-2013-4553,v 1.1 2013/11/29 19:29:58 drochner Exp $
http://lists.xenproject.org/archives/html/xen-devel/2013-11/msg03828.html
--- xen/arch/x86/domctl.c.orig 2013-09-10 06:42:18.000000000 +0000
+++ xen/arch/x86/domctl.c 2013-11-29 15:19:13.000000000 +0000
@@ -383,6 +383,26 @@ long arch_do_domctl(
break;
}
+ /*
+ * XSA-74: This sub-hypercall is broken in several ways:
+ * - lock order inversion (p2m locks inside page_alloc_lock)
+ * - no preemption on huge max_pfns input
+ * - not (re-)checking d->is_dying with page_alloc_lock held
+ * - not honoring start_pfn input (which libxc also doesn't set)
+ * Additionally it is rather useless, as the result is stale by
+ * the time the caller gets to look at it.
+ * As it only has a single, non-production consumer (xen-mceinj),
+ * rather than trying to fix it we restrict it for the time being.
+ */
+ if ( /* No nested locks inside copy_to_guest_offset(). */
+ paging_mode_external(current->domain) ||
+ /* Arbitrary limit capping processing time. */
+ max_pfns > GB(4) / PAGE_SIZE )
+ {
+ ret = -EOPNOTSUPP;
+ break;
+ }
+
spin_lock(&d->page_alloc_lock);
if ( unlikely(d->is_dying) ) {