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* [PATCH] mm: Prevent mapping typed pages to userspace
@ 2019-01-29  5:38 Matthew Wilcox
  2019-01-29  8:09   ` Kees Cook
  2019-01-30 12:01 ` David Hildenbrand
  0 siblings, 2 replies; 4+ messages in thread
From: Matthew Wilcox @ 2019-01-29  5:38 UTC (permalink / raw)
  To: Andrew Morton
  Cc: Matthew Wilcox, linux-mm, linux-kernel, kernel-hardening,
	Kees Cook, Michael Ellerman, Will Deacon

Pages which use page_type must never be mapped to userspace as it would
destroy their page type.  Add an explicit check for this instead of
assuming that kernel drivers always get this right.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
---
 mm/memory.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index ce8c90b752be..db3534bbd652 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1451,7 +1451,7 @@ static int insert_page(struct vm_area_struct *vma, unsigned long addr,
 	spinlock_t *ptl;
 
 	retval = -EINVAL;
-	if (PageAnon(page) || PageSlab(page))
+	if (PageAnon(page) || PageSlab(page) || page_has_type(page))
 		goto out;
 	retval = -ENOMEM;
 	flush_dcache_page(page);
-- 
2.20.1


^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, other threads:[~2019-01-30 12:01 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2019-01-29  5:38 [PATCH] mm: Prevent mapping typed pages to userspace Matthew Wilcox
2019-01-29  8:09 ` Kees Cook
2019-01-29  8:09   ` Kees Cook
2019-01-30 12:01 ` David Hildenbrand

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