net: tcp_probe: adapt tbuf size for recent changes

With recent changes in tcp_probe module (e.g. f925d0a6 ("net: tcp_probe:
add IPv6 support")) we also need to take into account that tbuf needs to
be updated as format string will be further expanded. tbuf sits on the stack
in tcpprobe_read() function that is invoked when user space reads procfs
file /proc/net/tcpprobe, hence not fast path as in jtcp_rcv_established().
Having a size similarly as in sctp_probe module of 256 bytes is fully
sufficient for that, we need theoretical maximum of 252 bytes otherwise we
could get truncated.
Signed-off-by: NDaniel Borkmann <dborkman@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/tcp_probe.c

@@ -218,7 +218,7 @@ static ssize_t tcpprobe_read(struct file *file, char __user *buf,
 		return -EINVAL;
 
 	while (cnt < len) {
-		char tbuf[164];
+		char tbuf[256];
 		int width;
 
 		/* Wait for data in buffer */