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Message-Id: <20190125173827.2658-1-willy@infradead.org>
Date: Fri, 25 Jan 2019 09:38:27 -0800
From: Matthew Wilcox <willy@...radead.org>
To: Andrew Morton <akpm@...ux-foundation.org>
Cc: Matthew Wilcox <willy@...radead.org>,
linux-mm@...ck.org,
linux-kernel@...r.kernel.org,
Rik van Riel <riel@...riel.com>,
Christoph Lameter <cl@...ux.com>,
Pekka Enberg <penberg@...nel.org>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>,
kernel-hardening@...ts.openwall.com,
Kees Cook <keescook@...omium.org>,
Michael Ellerman <mpe@...erman.id.au>
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.
Signed-off-by: Matthew Wilcox <willy@...radead.org>
---
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);
--
2.20.1
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