Received-SPF: pass (google.com: domain of linux-wireless-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Minsuk Kang <linuxlovemin@yonsei.ac.kr>
To:     linux-wireless@vger.kernel.org, toke@toke.dk
Cc:     kvalo@kernel.org, dokyungs@yonsei.ac.kr, jisoo.jang@yonsei.ac.kr,
        Minsuk Kang <linuxlovemin@yonsei.ac.kr>
Subject: [PATCH v2] ath9k: Fix potential stack-out-of-bounds write in ath9k_wmi_rsp_callback()
Date:   Wed,  4 Jan 2023 21:41:30 +0900
Message-Id: <20230104124130.10996-1-linuxlovemin@yonsei.ac.kr>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

Fix a stack-out-of-bounds write that occurs in a WMI response callback
function that is called after a timeout occurs in ath9k_wmi_cmd().
The callback writes to wmi->cmd_rsp_buf, a stack-allocated buffer that
could no longer be valid when a timeout occurs. Set wmi->last_seq_id to
0 when a timeout occurred.

Found by a modified version of syzkaller.

BUG: KASAN: stack-out-of-bounds in ath9k_wmi_ctrl_rx
Write of size 4
Call Trace:
 memcpy
 ath9k_wmi_ctrl_rx
 ath9k_htc_rx_msg
 ath9k_hif_usb_reg_in_cb
 __usb_hcd_giveback_urb
 usb_hcd_giveback_urb
 dummy_timer
 call_timer_fn
 run_timer_softirq
 __do_softirq
 irq_exit_rcu
 sysvec_apic_timer_interrupt

Signed-off-by: Minsuk Kang <linuxlovemin@yonsei.ac.kr>
---
v1->v2:
  Reset wmi->last_seq_id to 0 instead of introducing a new 'timedout'
  field when a timeout occurred.

 drivers/net/wireless/ath/ath9k/wmi.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/wireless/ath/ath9k/wmi.c b/drivers/net/wireless/ath/ath9k/wmi.c
index f315c54bd3ac..19345b8f7bfd 100644
--- a/drivers/net/wireless/ath/ath9k/wmi.c
+++ b/drivers/net/wireless/ath/ath9k/wmi.c
@@ -341,6 +341,7 @@ int ath9k_wmi_cmd(struct wmi *wmi, enum wmi_cmd_id cmd_id,
 	if (!time_left) {
 		ath_dbg(common, WMI, "Timeout waiting for WMI command: %s\n",
 			wmi_cmd_to_name(cmd_id));
+		wmi->last_seq_id = 0;
 		mutex_unlock(&wmi->op_mutex);
 		return -ETIMEDOUT;
 	}
-- 
2.25.1