mac80211_hwsim: check that n_limits makes sense

Under certain circumstances, radios created via netlink could
have n_limits be zero and no possible interface types, which
makes no sense. Reject this early to prevent a WARN_ON() in
cfg80211.

Fixes: 99e3a44bac37 ("mac80211_hwsim: allow setting iftype support")
Reported-by: syzbot+73fd8b0aa60c67fa4b60@syzkaller.appspotmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/drivers/net/wireless/mac80211_hwsim.c b/drivers/net/wireless/mac80211_hwsim.c
index 3a4b878..320edca 100644 (file)
--- a/drivers/net/wireless/mac80211_hwsim.c
+++ b/drivers/net/wireless/mac80211_hwsim.c
@@ -2761,6 +2761,11 @@ static int mac80211_hwsim_new_radio(struct genl_info *info,
                                        BIT(NL80211_CHAN_WIDTH_160);
        }
 
+       if (!n_limits) {
+               err = -EINVAL;
+               goto failed_hw;
+       }
+
        data->if_combination.n_limits = n_limits;
        data->if_combination.max_interfaces = 2048;
        data->if_combination.limits = data->if_limits;