Patch "wifi: ath9k: protect WMI command response buffer replacement with a lock" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    wifi: ath9k: protect WMI command response buffer replacement with a lock

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     wifi-ath9k-protect-wmi-command-response-buffer-repla.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 6601f2d0dd36a45548f4ea4f398ffeb578eb0b8b
Author: Fedor Pchelkin <pchelkin@xxxxxxxxx>
Date:   Tue Apr 25 22:26:07 2023 +0300

    wifi: ath9k: protect WMI command response buffer replacement with a lock
    
    [ Upstream commit 454994cfa9e4c18b6df9f78b60db8eadc20a6c25 ]
    
    If ath9k_wmi_cmd() has exited with a timeout, it is possible that during
    next ath9k_wmi_cmd() call the wmi_rsp callback for previous wmi command
    writes to new wmi->cmd_rsp_buf and makes a completion. This results in an
    invalid ath9k_wmi_cmd() return value.
    
    Move the replacement of WMI command response buffer and length under
    wmi_lock. Note that last_seq_id value is updated there, too.
    
    Thus, the buffer cannot be written to by a belated wmi_rsp callback
    because that path is properly rejected by the last_seq_id check.
    
    Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
    
    Fixes: fb9987d0f748 ("ath9k_htc: Support for AR9271 chipset.")
    Signed-off-by: Fedor Pchelkin <pchelkin@xxxxxxxxx>
    Acked-by: Toke Høiland-Jørgensen <toke@xxxxxxx>
    Signed-off-by: Kalle Valo <quic_kvalo@xxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20230425192607.18015-2-pchelkin@xxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index 96482ad23145c..dd8027b8af63e 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -280,7 +280,8 @@ int ath9k_wmi_connect(struct htc_target *htc, struct wmi *wmi,
 
 static int ath9k_wmi_cmd_issue(struct wmi *wmi,
 			       struct sk_buff *skb,
-			       enum wmi_cmd_id cmd, u16 len)
+			       enum wmi_cmd_id cmd, u16 len,
+			       u8 *rsp_buf, u32 rsp_len)
 {
 	struct wmi_cmd_hdr *hdr;
 	unsigned long flags;
@@ -290,6 +291,11 @@ static int ath9k_wmi_cmd_issue(struct wmi *wmi,
 	hdr->seq_no = cpu_to_be16(++wmi->tx_seq_id);
 
 	spin_lock_irqsave(&wmi->wmi_lock, flags);
+
+	/* record the rsp buffer and length */
+	wmi->cmd_rsp_buf = rsp_buf;
+	wmi->cmd_rsp_len = rsp_len;
+
 	wmi->last_seq_id = wmi->tx_seq_id;
 	spin_unlock_irqrestore(&wmi->wmi_lock, flags);
 
@@ -330,11 +336,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 		goto out;
 	}
 
-	/* record the rsp buffer and length */
-	wmi->cmd_rsp_buf = rsp_buf;
-	wmi->cmd_rsp_len = rsp_len;
-
-	ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len);
+	ret = ath9k_wmi_cmd_issue(wmi, skb, cmd_id, cmd_len, rsp_buf, rsp_len);
 	if (ret)
 		goto out;