From 0ee930e6cafa048c1925893d0ca89918b2814f2c Mon Sep 17 00:00:00 2001 From: Matthew Wilcox <willy@infradead.org> Date: Tue, 5 Mar 2019 15:46:06 -0800 Subject: [PATCH] mm/memory.c: prevent mapping typed pages to userspace 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. Link: http://lkml.kernel.org/r/20190129053830.3749-1-willy@infradead.org Signed-off-by: Matthew Wilcox <willy@infradead.org> Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: David Hildenbrand <david@redhat.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- mm/memory.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/memory.c b/mm/memory.c index a9897dcd530fb..79e0173a7d70e 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) || PageSlab(page)) + if (PageAnon(page) || PageSlab(page) || page_has_type(page)) goto out; retval = -ENOMEM; flush_dcache_page(page); -- GitLab