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

[Xen patchbot-unstable <patchbot@xxxxxxx>]

# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1354646311 0
# Node ID bc624b00d6d601f00a53c2f7502a82dcef60f882
# Parent  f2c836302c0fc21a58b307a4cd7418734f1f721e
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 f2c836302c0f -r bc624b00d6d6 xen/include/asm-x86/p2m.h
--- a/xen/include/asm-x86/p2m.h Tue Dec 04 18:38:26 2012 +0000
+++ b/xen/include/asm-x86/p2m.h Tue Dec 04 18:38:31 2012 +0000
@@ -384,7 +384,7 @@ 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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