Commit b7e4b65f authored by Al Viro's avatar Al Viro
Browse files

bpf: make bpf_check_uarg_tail_zero() use check_zeroed_user() 



... rather than open-coding it, and badly, at that.

Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 9eb41c52

kernel/bpf/syscall.c

+6 −19
Original line number Diff line number Diff line
@@ -67,32 +67,19 @@ int bpf_check_uarg_tail_zero(void __user *uaddr, 
			     size_t expected_size,

			     size_t actual_size)

{

	unsigned char __user *addr;

	unsigned char __user *end;

	unsigned char val;

	int err;

	unsigned char __user *addr = uaddr + expected_size;

	int res;



	if (unlikely(actual_size > PAGE_SIZE))	/* silly large */

		return -E2BIG;



	if (unlikely(!access_ok(uaddr, actual_size)))

		return -EFAULT;



	if (actual_size <= expected_size)

		return 0;



	addr = uaddr + expected_size;

	end  = uaddr + actual_size;



	for (; addr < end; addr++) {

		err = get_user(val, addr);

		if (err)

			return err;

		if (val)

			return -E2BIG;

	}



	return 0;

	res = check_zeroed_user(addr, actual_size - expected_size);

	if (res < 0)

		return res;

	return res ? 0 : -E2BIG;

}



const struct bpf_map_ops bpf_map_offload_ops = {