| Message ID | 20230216192301.171225-1-pchelkin@ispras.ru |
|---|---|
| State | New |
| Headers | show |
| Series | [v2] wifi: ath9k: hif_usb: fix memory leak of remain_skbs | expand |
Fedor Pchelkin <pchelkin@ispras.ru> wrote: > 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> Patch applied to ath-next branch of ath.git, thanks. 7654cc03eb69 wifi: ath9k: hif_usb: fix memory leak of remain_skbs
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index f521dfa2f194..e0130beb304d 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)
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> --- v1->v2: move ath9k_hif_usb_free_rx_remain_skb call into urbs dealloc function as advised by Toke; add a stat macro drivers/net/wireless/ath/ath9k/hif_usb.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+)