[PATCH 4.9 24/32] ife: error out when nla attributes are empty

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

From: Cong Wang <xiyou.wangcong@gmail.com>

[ Upstream commit c8ec4632c6ac9cda0e8c3d51aa41eeab66585bd5 ]

act_ife at least requires TCA_IFE_PARMS, so we have to bail out
when there is no attribute passed in.

Reported-by: syzbot+fbb5b288c9cb6a2eeac4@syzkaller.appspotmail.com
Fixes: ef6980b6becb ("introduce IFE action")
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/sched/act_ife.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -477,6 +477,9 @@ static int tcf_ife_init(struct net *net,
 	int ret = 0;
 	int err;
 
+	if (!nla)
+		return -EINVAL;
+
 	err = nla_parse_nested(tb, TCA_IFE_MAX, nla, ife_policy);
 	if (err < 0)
 		return err;