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Commit 9b61a4d1 authored by Russell King's avatar Russell King
Browse files

ARM: prevent VM_GROWSDOWN mmaps extending below FIRST_USER_ADDRESS 



Cc: <stable@vger.kernel.org>
Reported-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 998de4ac

arch/arm/mm/fault.c

+3 −1
Original line number Diff line number Diff line
@@ -247,7 +247,9 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr, 
	return handle_mm_fault(mm, vma, addr & PAGE_MASK, flags);



check_stack:

	if (vma->vm_flags & VM_GROWSDOWN && !expand_stack(vma, addr))

	/* Don't allow expansion below FIRST_USER_ADDRESS */

	if (vma->vm_flags & VM_GROWSDOWN &&

	    addr >= FIRST_USER_ADDRESS && !expand_stack(vma, addr))

		goto good_area;

out:

	return fault;