From: Fedor Pchelkin pchelkin@ispras.ru
[ Upstream commit dd95f2239fc846795fc926787c3ae0ca701c9840 ]
It is possible that skb is freed in ath9k_htc_rx_msg(), then usb_submit_urb() fails and we try to free skb again. It causes use-after-free bug. Moreover, if alloc_skb() fails, urb->context becomes NULL but rx_buf is not freed and there can be a memory leak.
The patch removes unnecessary nskb and makes skb processing more clear: it is supposed that ath9k_htc_rx_msg() either frees old skb or passes its managing to another callback function.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
Fixes: 3deff76095c4 ("ath9k_htc: Increase URB count for REG_IN pipe") 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/20221008114917.21404-1-pchelkin@ispras.ru Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/wireless/ath/ath9k/hif_usb.c | 28 +++++++++++++----------- 1 file changed, 15 insertions(+), 13 deletions(-)
diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c index 4290753a2002..d872459c51cc 100644 --- a/drivers/net/wireless/ath/ath9k/hif_usb.c +++ b/drivers/net/wireless/ath/ath9k/hif_usb.c @@ -709,14 +709,13 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) struct rx_buf *rx_buf = (struct rx_buf *)urb->context; struct hif_device_usb *hif_dev = rx_buf->hif_dev; struct sk_buff *skb = rx_buf->skb; - struct sk_buff *nskb; int ret;
if (!skb) return;
if (!hif_dev) - goto free; + goto free_skb;
switch (urb->status) { case 0: @@ -725,7 +724,7 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) case -ECONNRESET: case -ENODEV: case -ESHUTDOWN: - goto free; + goto free_skb; default: skb_reset_tail_pointer(skb); skb_trim(skb, 0); @@ -736,25 +735,27 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) if (likely(urb->actual_length != 0)) { skb_put(skb, urb->actual_length);
- /* Process the command first */ + /* + * Process the command first. + * skb is either freed here or passed to be + * managed to another callback function. + */ ath9k_htc_rx_msg(hif_dev->htc_handle, skb, skb->len, USB_REG_IN_PIPE);
- - nskb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC); - if (!nskb) { + skb = alloc_skb(MAX_REG_IN_BUF_SIZE, GFP_ATOMIC); + if (!skb) { dev_err(&hif_dev->udev->dev, "ath9k_htc: REG_IN memory allocation failure\n"); - urb->context = NULL; - return; + goto free_rx_buf; }
- rx_buf->skb = nskb; + rx_buf->skb = skb;
usb_fill_int_urb(urb, hif_dev->udev, usb_rcvintpipe(hif_dev->udev, USB_REG_IN_PIPE), - nskb->data, MAX_REG_IN_BUF_SIZE, + skb->data, MAX_REG_IN_BUF_SIZE, ath9k_hif_usb_reg_in_cb, rx_buf, 1); }
@@ -763,12 +764,13 @@ static void ath9k_hif_usb_reg_in_cb(struct urb *urb) ret = usb_submit_urb(urb, GFP_ATOMIC); if (ret) { usb_unanchor_urb(urb); - goto free; + goto free_skb; }
return; -free: +free_skb: kfree_skb(skb); +free_rx_buf: kfree(rx_buf); urb->context = NULL; }