rtlwifi: Fix potential overflow on P2P code

mainline inclusion
from mainline-v5.4
commit 8c55dedb
category: 13690
bugzilla: NA
CVE: CVE-2019-17666

-------------------------------------------------

Nicolas Waisman noticed that even though noa_len is checked for
a compatible length it's still possible to overrun the buffers
of p2pinfo since there's no check on the upper bound of noa_num.
Bound noa_num against P2P_MAX_NOA_NUM.
Reported-by: NNicolas Waisman <nico@semmle.com>
Signed-off-by: NLaura Abbott <labbott@redhat.com>
Acked-by: NPing-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org
Signed-off-by: NYang Yingliang <yangyingliang@huawei.com>

drivers/net/wireless/realtek/rtlwifi/ps.c

@@ -775,6 +775,9 @@ static void rtl_p2p_noa_ie(struct ieee80211_hw *hw, void *data,
 				return;
 			} else {
 				noa_num = (noa_len - 2) / 13;
+				if (noa_num > P2P_MAX_NOA_NUM)
+					noa_num = P2P_MAX_NOA_NUM;
+
 			}
 			noa_index = ie[3];
 			if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==
@@ -869,6 +872,9 @@ static void rtl_p2p_action_ie(struct ieee80211_hw *hw, void *data,
 				return;
 			} else {
 				noa_num = (noa_len - 2) / 13;
+				if (noa_num > P2P_MAX_NOA_NUM)
+					noa_num = P2P_MAX_NOA_NUM;
+
 			}
 			noa_index = ie[3];
 			if (rtlpriv->psc.p2p_ps_info.p2p_ps_mode ==