wifi: wcn36xx: fix heap overflow from oversized firmware HAL response

The firmware response dispatcher copies all synchronous HAL responses
into the 4096-byte hal_buf without validating the response length. A
response exceeding WCN36XX_HAL_BUF_SIZE causes a heap buffer overflow
with firmware-controlled content.

Add a bounds check on the response length.

Fixes: 8e84c25821 ("wcn36xx: mac80211 driver for Qualcomm WCN3660/WCN3680 hardware")
Signed-off-by: Tristan Madani <tristan@talencesecurity.com>
Reviewed-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
Link: https://patch.msgid.link/20260421135018.352774-2-tristmd@gmail.com
Signed-off-by: Jeff Johnson <jeff.johnson@oss.qualcomm.com>

drivers/net/wireless/ath/wcn36xx/smd.c

@@ -3293,6 +3293,10 @@ int wcn36xx_smd_rsp_process(struct rpmsg_device *rpdev,
 	case WCN36XX_HAL_EXIT_IMPS_RSP:
 	case WCN36XX_HAL_UPDATE_CHANNEL_LIST_RSP:
 	case WCN36XX_HAL_ADD_BCN_FILTER_RSP:
+		if (len > WCN36XX_HAL_BUF_SIZE) {
+			wcn36xx_warn("HAL response too large: %d\n", len);
+			break;
+		}
 		memcpy(wcn->hal_buf, buf, len);
 		wcn->hal_rsp_len = len;
 		complete(&wcn->hal_rsp_compl);