wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails

wifi: ath9k: hif_usb: clean up skbs if ath9k_hif_usb_rx_stream() fails

[ Upstream commit 0af54343a76263a12dbae7fafb64eb47c4a6ad38 ]

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 input skb is considered invalid
and dropped. All the associated packets already in skb_pool should be
dropped and freed. Added a comment describing this issue.

The patch also makes remain_skb NULL after being processed so that it
cannot be referenced after potential free. The initialization of hif_dev
fields which are associated with remain_skb (rx_remain_len,
rx_transfer_len and rx_pad_len) is moved after a new remain_skb is
allocated.

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

Fixes: 20ab5ea601e1 ("ath9k: Fix out-of-bound memcpy in ath9k_hif_usb_rx_stream")
Fixes: fb8b0a9cd4d5 ("ath9k: hif_usb: Reduce indent 1 column")
Reported-by: syzbot+e9632e3eb038d93d6bc6@syzkaller.appspotmail.com
Signed-off-by: Fedor Pchelkin <pchelkin@ispras.ru>
Signed-off-by: Alexey Khoroshilov <khoroshilov@ispras.ru>
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk>
Signed-off-by: Kalle Valo <quic_kvalo@quicinc.com>
Link: https://lore.kernel.org/r/20230104123615.51511-1-pchelkin@ispras.ru
Signed-off-by: Sasha Levin <sashal@kernel.org>