Staging: rtl8723bs: rtw_wlan_util: Add size check of SSID IE

Add size check of SSID information element in incoming 802.11
frames, to prevent memcpy() of IE in array bssid->Ssid.Ssid, with
size more than 32 bytes.

Signed-off-by: Denis Straghkov <d.straghkov@ispras.ru>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Link: https://lore.kernel.org/r/20200421212525.24962-1-d.straghkov@ispras.ru
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
index 110338dbe3728cd257d2cef33391e66c2cf4d8a0..69bcd172b2987c2e19ddfc48e816c92fea19803d 100644 (file)
--- a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
+++ b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
@@ -1271,13 +1271,13 @@ int rtw_check_bcn_info(struct adapter *Adapter, u8 *pframe, u32 packet_len)
        unsigned char *pbuf;
        u32 wpa_ielen = 0;
        u8 *pbssid = GetAddr3Ptr(pframe);
-       u32 hidden_ssid = 0;
        struct HT_info_element *pht_info = NULL;
        struct rtw_ieee80211_ht_cap *pht_cap = NULL;
        u32 bcn_channel;
        unsigned short  ht_cap_info;
        unsigned char ht_info_infos_0;
        struct mlme_priv *pmlmepriv = &Adapter->mlmepriv;
+       int ssid_len;
 
        if (is_client_associated_to_ap(Adapter) == false)
                return true;
@@ -1370,21 +1370,15 @@ int rtw_check_bcn_info(struct adapter *Adapter, u8 *pframe, u32 packet_len)
        }
 
        /* checking SSID */
+       ssid_len = 0;
        p = rtw_get_ie(bssid->IEs + _FIXED_IE_LENGTH_, _SSID_IE_, &len, bssid->IELength - _FIXED_IE_LENGTH_);
-       if (!p) {
-               DBG_871X("%s marc: cannot find SSID for survey event\n", __func__);
-               hidden_ssid = true;
-       } else {
-               hidden_ssid = false;
-       }
-
-       if ((NULL != p) && (false == hidden_ssid && (*(p + 1)))) {
-               memcpy(bssid->Ssid.Ssid, (p + 2), *(p + 1));
-               bssid->Ssid.SsidLength = *(p + 1);
-       } else {
-               bssid->Ssid.SsidLength = 0;
-               bssid->Ssid.Ssid[0] = '\0';
+       if (p) {
+               ssid_len = *(p + 1);
+               if (ssid_len > NDIS_802_11_LENGTH_SSID)
+                       ssid_len = 0;
        }
+       memcpy(bssid->Ssid.Ssid, (p + 2), ssid_len);
+       bssid->Ssid.SsidLength = ssid_len;
 
        RT_TRACE(_module_rtl871x_mlme_c_, _drv_info_, ("%s bssid.Ssid.Ssid:%s bssid.Ssid.SsidLength:%d "
                                "cur_network->network.Ssid.Ssid:%s len:%d\n", __func__, bssid->Ssid.Ssid,