ARM: prevent VM_GROWSDOWN mmaps extending below FIRST_USER_ADDRESS

commit 9b61a4d1b2 upstream.

Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Russell King 2012-05-16 15:19:20 +01:00 committed by Greg Kroah-Hartman
parent 1c1cb5756a
commit dbda13fc21

View File

@ -266,7 +266,9 @@ __do_page_fault(struct mm_struct *mm, unsigned long addr, unsigned int fsr,
return fault;
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;