[Xen-changelog] [xen stable-4.2] page-alloc: scrub pages used by hypervisor upon freeing

[patchbot@xxxxxxx]

commit 83b88fd9c80d0bd147c77a2708326790a693a5ee
Author:     Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Tue Jun 17 16:07:28 2014 +0200
Commit:     Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Tue Jun 17 16:07:28 2014 +0200

    page-alloc: scrub pages used by hypervisor upon freeing
    
    ... unless they're part of a fully separate pool (and hence can't ever
    be used for guest allocations).
    
    This is CVE-2014-4021 / XSA-100.
    
    Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
    Reviewed-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
    Acked-by: Keir Fraser <keir@xxxxxxx>
    master commit: 4bd78937ec324bcef4e29ef951e0ff9815770de1
    master date: 2014-06-17 15:21:10 +0200
---
 xen/common/page_alloc.c |    5 +++++
 1 files changed, 5 insertions(+), 0 deletions(-)

diff --git a/xen/common/page_alloc.c b/xen/common/page_alloc.c
index 5cba5e0..c32bbe1 100644
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -1254,7 +1254,10 @@ void free_xenheap_pages(void *v, unsigned int order)
     pg = virt_to_page(v);
 
     for ( i = 0; i < (1u << order); i++ )
+    {
+        scrub_one_page(&pg[i]);
         pg[i].count_info &= ~PGC_xen_heap;
+    }
 
     free_heap_pages(pg, order);
 }
@@ -1421,6 +1424,8 @@ void free_domheap_pages(struct page_info *pg, unsigned 
int order)
     else
     {
         /* Freeing anonymous domain-heap pages. */
+        for ( i = 0; i < (1 << order); i++ )
+            scrub_one_page(&pg[i]);
         free_heap_pages(pg, order);
         drop_dom_ref = 0;
     }
--
generated by git-patchbot for /home/xen/git/xen.git#stable-4.2

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