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xen/pvcalls: use alloc/free_pages_exact()

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Instead of __get_free_pages() and free_pages() use alloc_pages_exact()
and free_pages_exact(). This is in preparation of a change of
gnttab_end_foreign_access() which will prohibit use of high-order
pages.

This is part of CVE-2022-23041 / XSA-396.

Reported-by: Simon Gaiser <simon@invisiblethingslab.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
---
V4:
- new patch
This commit is contained in:
Juergen Gross 2022-03-07 09:48:55 +01:00
parent 5cadd4bb1d
commit b0576cc9c6
1 changed files with 4 additions and 4 deletions
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8
drivers/xen/pvcalls-front.c
View File

@ -337,8 +337,8 @@ static void free_active_ring(struct sock_mapping *map)
if (!map->active.ring)
return;
free_pages((unsigned long)map->active.data.in,
map->active.ring->ring_order);
free_pages_exact(map->active.data.in,
PAGE_SIZE << map->active.ring->ring_order);
free_page((unsigned long)map->active.ring);
}
@ -352,8 +352,8 @@ static int alloc_active_ring(struct sock_mapping *map)
goto out;
map->active.ring->ring_order = PVCALLS_RING_ORDER;
bytes = (void *)__get_free_pages(GFP_KERNEL | __GFP_ZERO,
PVCALLS_RING_ORDER);
bytes = alloc_pages_exact(PAGE_SIZE << PVCALLS_RING_ORDER,
GFP_KERNEL | __GFP_ZERO);
if (!bytes)
goto out;