[patch] Staging: rtl8188eu: overflow in update_sta_support_rate()

[Dan Carpenter]

The ->SupportedRates[] array has NDIS_802_11_LENGTH_RATES_EX (16)
elements.  Since "ie_len" comes from then network and can go up to 255
then it means we should add a range check to prevent memory corruption.

Fixes: d6846af679e0 ('staging: r8188eu: Add files for new driver - part 7')
Signed-off-by: Dan Carpenter <dan.carpen...@oracle.com>

diff --git a/drivers/staging/rtl8188eu/core/rtw_wlan_util.c 
b/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
index 3dd9059..6c9e9a1 100644
--- a/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
+++ b/drivers/staging/rtl8188eu/core/rtw_wlan_util.c
@@ -1599,13 +1599,18 @@ int update_sta_support_rate(struct adapter *padapter, 
u8 *pvar_ie, uint var_ie_l
        pIE = (struct ndis_802_11_var_ie *)rtw_get_ie(pvar_ie, 
_SUPPORTEDRATES_IE_, &ie_len, var_ie_len);
        if (pIE == NULL)
                return _FAIL;
+       if (ie_len > NDIS_802_11_LENGTH_RATES_EX)
+               return _FAIL;
 
        memcpy(pmlmeinfo->FW_sta_info[cam_idx].SupportedRates, pIE->data, 
ie_len);
        supportRateNum = ie_len;
 
        pIE = (struct ndis_802_11_var_ie *)rtw_get_ie(pvar_ie, 
_EXT_SUPPORTEDRATES_IE_, &ie_len, var_ie_len);
-       if (pIE)
+       if (pIE) {
+               if (supportRateNum + ie_len > NDIS_802_11_LENGTH_RATES_EX)
+                       return _FAIL;
                memcpy((pmlmeinfo->FW_sta_info[cam_idx].SupportedRates + 
supportRateNum), pIE->data, ie_len);
+       }
 
        return _SUCCESS;
 }
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