Commit 5a211a5d authored Dec 04, 2007 by Eric Paris Committed by James Morris Dec 06, 2007

VM/Security: add security hook to do_brk



Given a specifically crafted binary do_brk() can be used to get low
pages available in userspace virtually memory and can thus be used to
circumvent the mmap_min_addr low memory protection.  Add security checks
in do_brk().

Signed-off-by: Eric Paris <eparis@redhat.com>
Acked-by: Alan Cox <alan@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

parent 7cd94146

mm/mmap.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1941,6 +1941,10 @@ unsigned long do_brk(unsigned long addr, unsigned long len)
		if (is_hugepage_only_range(mm, addr, len))
		return -EINVAL;

		error = security_file_mmap(0, 0, 0, 0, addr, 1);
		if (error)
		return error;

		flags = VM_DATA_DEFAULT_FLAGS \| VM_ACCOUNT \| mm->def_flags;

		error = arch_mmap_check(addr, len, flags);