[Xen-changelog] [xen-4.2-testing] x86: get_page_from_gfn() must return NULL for invalid GFNs

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

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1354644179 0
# Node ID b306bce613413c772af7a7660c9fd44d347b5ee2
# Parent  2c3f00c5189b9269f9840be93d03f058c8994f6e
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@xxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
Committed-by: Ian Jackson <ian.jackson.citrix.com>
---


diff -r 2c3f00c5189b -r b306bce61341 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Tue Dec 04 18:02:52 2012 +0000
+++ b/xen/include/asm-x86/p2m.h Tue Dec 04 18:02:59 2012 +0000
@@ -400,7 +400,7 @@ static inline struct page_info *get_page
     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;
 }
 
 

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