ath9k: Fix potential out of bounds in ath9k_htc_txcompletion_cb()

The value of "htc_hdr->endpoint_id" comes from skb->data so Smatch marks it as untrusted so we have to check it before using it as an array offset.

This is similar to a bug that syzkaller found in commit e4ff08a4d727 ("ath9k: Fix use-after-free Write in ath9k_htc_rx_msg") so it is probably a real issue.

---
 drivers/net/wireless/ath/ath9k/htc_hst.c | 2 ++
 1 file changed, 2 insertions(+)

index d2e062eaf561..510e61e97dbc 100644
@@ -339,6 +339,8 @@ void ath9k_htc_txcompletion_cb(struct htc_target *htc_handle,
 
 	if (skb) {
 		htc_hdr = (struct htc_frame_hdr *) skb->data;
+		if (htc_hdr->endpoint_id >= ARRAY_SIZE(htc_handle->endpoint))
+			goto ret;
 		endpoint = &htc_handle->endpoint[htc_hdr->endpoint_id];
 		skb_pull(skb, sizeof(struct htc_frame_hdr));
 

2.28.0

Patch applied to ath-next branch of ath.git, thanks.

2705cd7558e7 ath9k: Fix potential out of bounds in ath9k_htc_txcompletion_cb()

https://patchwork.kernel.org/patch/11712553/

https://wireless.wiki.kernel.org/en/developers/documentation/submittingpatches