um: Ensure that a stub page cannot get unmapped



Trinity discovered an execution path such that a task
can unmap his stub page.

Reported-by: Toralf Förster <toralf.foerster@gmx.de>
Signed-off-by: Richard Weinberger <richard@nod.at>

parent ae5db6d1

arch/um/kernel/tlb.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -124,6 +124,9 @@ static int add_munmap(unsigned long addr, unsigned long len,
		struct host_vm_op *last;
		int ret = 0;

		if ((addr >= STUB_START) && (addr < STUB_END))
		return -EINVAL;

		if (hvc->index != 0) {
		last = &hvc->ops[hvc->index - 1];
		if ((last->type == MUNMAP) &&