[PATCH 5.7 255/265] Staging: rtl8723bs: prevent buffer overflow in update_sta_support_rate()

Sasha Levin
2020-06-29T22:05:33Z

From: Dan Carpenter <dan.carpenter@oracle.com>

commit b65a2d8c8614386f7e8d38ea150749f8a862f431 upstream.

The "ie_len" variable is in the 0-255 range and it comes from the
network. If it's over NDIS_802_11_LENGTH_RATES_EX (16) then that will
lead to memory corruption.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200603101958.GA1845750@mwanda
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/staging/rtl8723bs/core/rtw_wlan_util.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
index 110338dbe3728..cc60f6a28d700 100644
--- a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
+++ b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
@@ -1830,12 +1830,14 @@ int update_sta_support_rate(struct adapter *padapter, u8 *pvar_ie, uint var_ie_l
pIE = (struct ndis_80211_var_ie *)rtw_get_ie(pvar_ie, _SUPPORTEDRATES_IE_, &ie_len, var_ie_len);
if (!pIE)
return _FAIL;
+ if (ie_len > sizeof(pmlmeinfo->FW_sta_info[cam_idx].SupportedRates))
+ return _FAIL;

memcpy(pmlmeinfo->FW_sta_info[cam_idx].SupportedRates, pIE->data, ie_len);
supportRateNum = ie_len;

pIE = (struct ndis_80211_var_ie *)rtw_get_ie(pvar_ie, _EXT_SUPPORTEDRATES_IE_, &ie_len, var_ie_len);
- if (pIE)
+ if (pIE && (ie_len <= sizeof(pmlmeinfo->FW_sta_info[cam_idx].SupportedRates) - supportRateNum))
memcpy((pmlmeinfo->FW_sta_info[cam_idx].SupportedRates + supportRateNum), pIE->data, ie_len);

return _SUCCESS;
--
2.25.1