On Tue, Mar 31, 2020 at 7:03 PM Kalle Valo [off-list ref] wrote:

Qiujun Huang [off-list ref] writes:

quoted

Add barrier to accessing the stack array skb_pool.

Reported-by: syzbot+d403396d4df67ad0bd5f@syzkaller.appspotmail.com
Signed-off-by: Qiujun Huang <redacted>
---
 drivers/net/wireless/ath/ath9k/hif_usb.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/net/wireless/ath/ath9k/hif_usb.c b/drivers/net/wireless/ath/ath9k/hif_usb.c
index dd0c323..c4a2b72 100644
--- a/drivers/net/wireless/ath/ath9k/hif_usb.c
+++ b/drivers/net/wireless/ath/ath9k/hif_usb.c

@@ -612,6 +612,11 @@ static void ath9k_hif_usb_rx_stream(struct hif_device_usb *hif_dev,
                      hif_dev->remain_skb = nskb;
                      spin_unlock(&hif_dev->rx_lock);
              } else {
+                     if (pool_index == MAX_PKT_NUM_IN_TRANSFER) {
+                             dev_err(&hif_dev->udev->dev,
+                                     "ath9k_htc: over RX MAX_PKT_NUM\n");
+                             goto err;
+                     }

What about 'pool_index >= MAX_PKT_NUM_IN_TRANSFER' just to be on the
safe side? Ah, but then error handling won't work:

Get that.

err:
        for (i = 0; i < pool_index; i++) {
                RX_STAT_ADD(skb_completed_bytes, skb_pool[i]->len);
                ath9k_htc_rx_msg(hif_dev->htc_handle, skb_pool[i],
                                 skb_pool[i]->len, USB_WLAN_RX_PIPE);
                RX_STAT_INC(skb_completed);
        }

Maybe that should use 'min(pool_index, MAX_PKT_NUM_IN_TRANSFER - 1)' or
something? Or maybe it's just overengineerin, dunno.

I will take a deeper look, thanks.

--
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