patch "Staging: rtl8723bs: prevent buffer overflow in" added to staging-linus

This is a note to let you know that I've just added the patch titled

Staging: rtl8723bs: prevent buffer overflow in

to my staging git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git
in the staging-linus branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the next -rc kernel release.

If you have any questions about this process, please let me know.

From b65a2d8c8614386f7e8d38ea150749f8a862f431 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <[email protected]>
Date: Wed, 3 Jun 2020 13:19:58 +0300
Subject: Staging: rtl8723bs: prevent buffer overflow in
update_sta_support_rate()

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.

---
 drivers/staging/rtl8723bs/core/rtw_wlan_util.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

index 69bcd172b298..a3ea7ce3e12e 100644
@@ -1824,12 +1824,14 @@ 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;

2.27.0