From 2d432cb7091e99881af803cdd67a31969b863005 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Tue, 5 Mar 2019 15:46:02 -0800 Subject: [PATCH] mm: prevent mapping slab pages to userspace 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. Christoph said: : Let's just fail the code. Currently this may work with SLUB. But SLAB : and SLOB overlay fields with mapcount. So you would have a corrupted page : struct if you mapped a slab page to user space. Link: http://lkml.kernel.org/r/20190125173827.2658-1-willy@infradead.org Signed-off-by: Matthew Wilcox Reviewed-by: Kees Cook Acked-by: Pekka Enberg Cc: Rik van Riel Cc: Christoph Lameter Cc: David Rientjes Cc: Joonsoo Kim Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index 222da66f16b4..a9897dcd530f 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -1452,7 +1452,7 @@ 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); -- 2.30.2