From 2705cd7558e718a7240c64eb0afb2edad5f8c190 Mon Sep 17 00:00:00 2001
From: Dan Carpenter <dan.carpenter@oracle.com>
Date: Thu, 13 Aug 2020 17:12:53 +0300
Subject: [PATCH] ath9k: Fix potential out of bounds in ath9k_htc_txcompletion_cb()
Git-commit: 2705cd7558e718a7240c64eb0afb2edad5f8c190
Patch-mainline: v5.10-rc1
References: git-fixes

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.

Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20200813141253.GA457408@mwanda
Acked-by: Takashi Iwai <tiwai@suse.de>

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

diff --git a/drivers/net/wireless/ath/ath9k/htc_hst.c b/drivers/net/wireless/ath/ath9k/htc_hst.c
index d2e062eaf561..510e61e97dbc 100644
--- a/drivers/net/wireless/ath/ath9k/htc_hst.c
+++ b/drivers/net/wireless/ath/ath9k/htc_hst.c
@@ -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));
 
-- 
2.16.4