rtlwifi: rtl_pci: Fix problem of too small skb->len

In commit 8020919a9b99 ("mac80211: Properly handle SKB with radiotap
only"), buffers whose length is too short cause a WARN_ON(1) to be
executed. This change exposed a fault in rtlwifi drivers, which is fixed
by regarding packets with skb->len <= FCS_LEN as though they are in error
and dropping them. The test is now annotated as likely.

Cc: Stable <stable@vger.kernel.org> # v5.0+
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
index 6087ec7..f88d265 100644 (file)
--- a/drivers/net/wireless/realtek/rtlwifi/pci.c
+++ b/drivers/net/wireless/realtek/rtlwifi/pci.c
@@ -822,7 +822,7 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
                hdr = rtl_get_hdr(skb);
                fc = rtl_get_fc(skb);
 
-               if (!stats.crc && !stats.hwerror) {
+               if (!stats.crc && !stats.hwerror && (skb->len > FCS_LEN)) {
                        memcpy(IEEE80211_SKB_RXCB(skb), &rx_status,
                               sizeof(rx_status));
 
@@ -859,6 +859,7 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
                                _rtl_pci_rx_to_mac80211(hw, skb, rx_status);
                        }
                } else {
+                       /* drop packets with errors or those too short */
                        dev_kfree_skb_any(skb);
                }
 new_trx_end: