[PATCH V3] rtlwifi: rtl_pci: Fix problem of too small skb->len

[PATCH V3] rtlwifi: rtl_pci: Fix problem of too small skb->len

[Larry Finger]

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>
---
V2 - content dropped
V3 - changed fix to drop packet rather than arbitrarily increasing the length.
---
Material for 5.4.
---
 drivers/net/wireless/realtek/rtlwifi/pci.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtlwifi/pci.c b/drivers/net/wireless/realtek/rtlwifi/pci.c
index 6087ec7a90a6..f88d26535978 100644
--- 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:
-- 
2.23.0

Re: [PATCH V3] rtlwifi: rtl_pci: Fix problem of too small skb->len

[Kalle Valo]

Larry Finger <Larry.Finger@lwfinger.net> writes:

> 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>
> ---
> V2 - content dropped
> V3 - changed fix to drop packet rather than arbitrarily increasing the length.

Much better, thanks.

> Material for 5.4.

Ok, I'll queue it for v5.4.

-- 
https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches

Re: [PATCH V3] rtlwifi: rtl_pci: Fix problem of too small skb->len

[Kalle Valo]

Larry Finger <Larry.Finger@lwfinger.net> wrote:

> 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>

Patch applied to wireless-drivers.git, thanks.

b43f4a169f22 rtlwifi: rtl_pci: Fix problem of too small skb->len

-- 
https://patchwork.kernel.org/patch/11201179/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches