From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit 7654cc03eb699297130b693ec34e25f77b17c947 ]
hif_dev->remain_skb is allocated and used exclusively in ath9k_hif_usb_rx_stream(). It is implied that an allocated remain_skb is processed and subsequently freed (in error paths) only during the next call of ath9k_hif_usb_rx_stream().
So, if the urbs are deallocated between those two calls due to the device deinitialization or suspend, it is possible that ath9k_hif_usb_rx_stream() is not called next time and the allocated remain_skb is leaked. Our local Syzkaller instance was able to trigger that.
remain_skb makes sense when receiving two consecutive urbs which are logically linked together, i.e. a specific data field from the first skb indicates a cached skb to be allocated, memcpy'd with some data and subsequently processed in the next call to ath9k_hif_usb_rx_stream(). Urbs deallocation supposedly makes that link irrelevant so we need to free the cached skb in those cases.
Fix the leak by introducing a function to explicitly free remain_skb (if it is not NULL) when the rx urbs have been deallocated. remain_skb is NULL when it has not been allocated at all (hif_dev struct is kzalloced) or when it has been processed in next call to ath9k_hif_usb_rx_stream().
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.") 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/20230216192301.171225-1-pchelkin@ispras.ru Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath9k/hif_usb.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index e23d58f83dd6f..3aa915d215545 100644 --- a/drivers/net/wireless/ath/ath9k/hif_usb.c +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c @@ -534,6 +534,24 @@ static struct ath9k_htc_hif hif_usb = { .send = hif_usb_send, };
+/* Need to free remain_skb allocated in ath9k_hif_usb_rx_stream + * in case ath9k_hif_usb_rx_stream wasn't called next time to + * process the buffer and subsequently free it. + */ +static void ath9k_hif_usb_free_rx_remain_skb(struct hif_device_usb *hif_dev) +{ + unsigned long flags; + + spin_lock_irqsave(&hif_dev->rx_lock, flags); + if (hif_dev->remain_skb) { + dev_kfree_skb_any(hif_dev->remain_skb); + hif_dev->remain_skb = NULL; + hif_dev->rx_remain_len = 0; + RX_STAT_INC(hif_dev, skb_dropped); + } + spin_unlock_irqrestore(&hif_dev->rx_lock, flags); +} + static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev, struct sk_buff *skb) { @@ -868,6 +886,7 @@ static int ath9k_hif_usb_alloc_tx_urbs(struct hif_device_usb *hif_dev) static void ath9k_hif_usb_dealloc_rx_urbs(struct hif_device_usb *hif_dev) { usb_kill_anchored_urbs(&hif_dev->rx_submitted); + ath9k_hif_usb_free_rx_remain_skb(hif_dev); }
static int ath9k_hif_usb_alloc_rx_urbs(struct hif_device_usb *hif_dev)