From f2ccf981beaa48bab1dba7e1642e08444e991d94 Mon Sep 17 00:00:00 2001
From: Jan Beulich <jbeulich@suse.com>
Date: Tue, 4 Dec 2012 18:02:59 +0000
Subject: [PATCH] x86: get_page_from_gfn() must return NULL for invalid GFNs

... also in the non-translated case.

This is XSA-32 / CVE-2012-xxxx.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Tim Deegan <tim@xen.org>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
---
 xen/include/asm-x86/p2m.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index 7a7c7eb12b..d5665b87fb 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -400,7 +400,7 @@ static inline struct page_info *get_page_from_gfn(
     if (t)
         *t = p2m_ram_rw;
     page = __mfn_to_page(gfn);
-    return get_page(page, d) ? page : NULL;
+    return mfn_valid(gfn) && get_page(page, d) ? page : NULL;
 }