From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) by kanga.kvack.org (Postfix) with ESMTP id 5CF978E00DF for ; Fri, 25 Jan 2019 12:38:47 -0500 (EST) Received: by mail-pg1-f197.google.com with SMTP id a2so6752971pgt.11 for ; Fri, 25 Jan 2019 09:38:47 -0800 (PST) Received: from bombadil.infradead.org (bombadil.infradead.org. [2607:7c80:54:e::133]) by mx.google.com with ESMTPS id m64si25262468pfb.224.2019.01.25.09.38.44 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 25 Jan 2019 09:38:44 -0800 (PST) From: Matthew Wilcox Subject: [PATCH] mm: Prevent mapping slab pages to userspace Date: Fri, 25 Jan 2019 09:38:27 -0800 Message-Id: <20190125173827.2658-1-willy@infradead.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Matthew Wilcox , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Rik van Riel , Christoph Lameter , Pekka Enberg , David Rientjes , Joonsoo Kim , kernel-hardening@lists.openwall.com, Kees Cook , Michael Ellerman 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 --- 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