rtlwifi: Fix potential overflow on P2P code

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: Nicolas Waisman <nico@semmle.com>
Signed-off-by: Laura Abbott <labbott@redhat.com>
Acked-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/realtek/rtlwifi/ps.c b/drivers/net/wireless/realtek/rtlwifi/ps.c
index 70f04c2..fff8dda 100644 (file)
--- a/drivers/net/wireless/realtek/rtlwifi/ps.c
+++ b/drivers/net/wireless/realtek/rtlwifi/ps.c
@@ -754,6 +754,9 @@ 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 ==
@@ -848,6 +851,9 @@ 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 ==