[PATCH v2 2/3] wifi: ath6kl: fix OOB read from firmware IE lengths in connect event

[Tristan Madani <tristmd@gmail.com>]

From: Tristan Madani <tristan@talencesecurity.com>

The firmware-controlled beacon_ie_len, assoc_req_len, and assoc_resp_len
fields in ath6kl_wmi_connect_event_rx() are not validated against the
buffer length. Their sum (up to 765) can exceed the actual WMI event
data, causing out-of-bounds reads during IE parsing and state corruption
of wmi->is_wmm_enabled.

Add a check that the total IE length fits within the buffer.

Fixes: bdcd81707973 ("Add ath6kl cleaned up driver")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
---
drivers/net/wireless/ath/ath6kl/wmi.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/wireless/ath/ath6kl/wmi.c b/drivers/net/wireless/ath/ath6kl/wmi.c
index XXXXXXX..XXXXXXX 100644
--- a/drivers/net/wireless/ath/ath6kl/wmi.c
+++ b/drivers/net/wireless/ath/ath6kl/wmi.c
@@ -860,6 +860,13 @@ static int ath6kl_wmi_connect_event_rx(struct wmi *wmi, u8 *datap, int len,

 	ev = (struct wmi_connect_event *) datap;

+	if (len < sizeof(*ev) + ev->beacon_ie_len +
+	    ev->assoc_req_len + ev->assoc_resp_len) {
+		ath6kl_dbg(ATH6KL_DBG_WMI,
+			   "connect event: IE lengths %u+%u+%u exceed buffer %d\n",
+			   ev->beacon_ie_len, ev->assoc_req_len,
+			   ev->assoc_resp_len, len);
+		return -EINVAL;
+	}
 	if (vif->nw_type == AP_NETWORK) {
 		/* AP mode start/STA connected event */
 		struct net_device *dev = vif->ndev;