Re: [PATCH net-next] tcp: fix null ptr deref in getsockopt(..., TCP_ULP, ...)

From: Dave Watson <redacted>
Date: Mon, 26 Jun 2017 08:36:47 -0700

If icsk_ulp_ops is unset, it dereferences a null ptr.
Add a null ptr check.

BUG: KASAN: null-ptr-deref in copy_to_user include/linux/uaccess.h:168 [inline]
BUG: KASAN: null-ptr-deref in do_tcp_getsockopt.isra.33+0x24f/0x1e30 net/ipv4/tcp.c:3057
Read of size 4 at addr 0000000000000020 by task syz-executor1/15452

Signed-off-by: Dave Watson <redacted>
Reported-by: "Levin, Alexander (Sasha Levin)" <redacted>

Applied, thanks.