[PATCH v2] wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails

[Fedor Pchelkin]

Syzkaller detected a memory leak of skbs in ath9k_hif_usb_rx_stream().
While processing skbs in ath9k_hif_usb_rx_stream(), the already allocated
skbs in skb_pool are not freed if ath9k_hif_usb_rx_stream() fails. If we
have an incorrect pkt_len or pkt_tag, the skb is dropped and all the
associated skb_pool buffers should be cleaned, too.

Found by Linux Verification Center (linuxtesting.org) with Syzkaller.

Fixes: 6ce708f54cc8 ("ath9k: Fix out-of-bound memcpy in ath9k_hif_usb_rx_stream")
Fixes: 44b23b488d44 ("ath9k: hif_usb: Reduce indent 1 column")
Reported-by: syzbot+e9632e3eb038d93d6bc6@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
Signed-off-by: Alexey Khoroshilov <khoroshilov@xxxxxxxxx>
---
v1->v2: added Reported-by tag

 drivers/net/wireless/ath/ath9k/hif_usb.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index 1a2e0c7eeb02..d02cec114280 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c
@@ -586,14 +586,14 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
 
 		if (pkt_tag != ATH_USB_RX_STREAM_MODE_TAG) {
 			RX_STAT_INC(hif_dev, skb_dropped);
-			return;
+			goto invalid_pkt;
 		}
 
 		if (pkt_len > 2 * MAX_RX_BUF_SIZE) {
 			dev_err(&hif_dev->udev->dev,
 				"ath9k_htc: invalid pkt_len (%x)\n", pkt_len);
 			RX_STAT_INC(hif_dev, skb_dropped);
-			return;
+			goto invalid_pkt;
 		}
 
 		pad_len = 4 - (pkt_len & 0x3);
@@ -654,6 +654,11 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
 				 skb_pool[i]->len, USB_WLAN_RX_PIPE);
 		RX_STAT_INC(hif_dev, skb_completed);
 	}
+	return;
+invalid_pkt:
+	for (i = 0; i < pool_index; i++)
+		kfree_skb(skb_pool[i]);
+	return;
 }
 
 static void ath9k_hif_usb_rx_cb(struct urb *urb)
-- 
2.34.1