On 25/01/2019 19.38, Matthew Wilcox wrote:
It's never appropriate to map a page allocated by SLAB into userspace.
A buggy device driver might try this, or an attacker might be able to
find a way to make it happen.
Signed-off-by: Matthew Wilcox <wi...@infradead.org>
Acked-by: Pekka Enberg <penb...@kernel.org>
A WARN_ON_ONCE() would be nice here to let those buggy drivers know that
they will no longer work.
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/memory.c b/mm/memory.c
index e11ca9dd823f..ce8c90b752be 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))
+ if (PageAnon(page) || PageSlab(page))
goto out;
retval = -ENOMEM;
flush_dcache_page(page);
