ath9k_htc: Fix array overflow

Use ENDPOINT_MAX instead of HST_ENDPOINT_MAX.
This fixes a stack corruption issue.

This is based on a patch sent by Dan Carpenter <error27@gmail.com>.
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NSujith <Sujith.Manoharan@atheros.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

drivers/net/wireless/ath/ath9k/htc_hst.c

@@ -39,7 +39,7 @@ static struct htc_endpoint *get_next_avail_ep(struct htc_endpoint *endpoint)
 {
 	enum htc_endpoint_id avail_epid;
 
-	for (avail_epid = ENDPOINT_MAX; avail_epid > ENDPOINT0; avail_epid--)
+	for (avail_epid = (ENDPOINT_MAX - 1); avail_epid > ENDPOINT0; avail_epid--)
 		if (endpoint[avail_epid].service_id == 0)
 			return &endpoint[avail_epid];
 	return NULL;
@@ -117,7 +117,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
 		max_msglen = be16_to_cpu(svc_rspmsg->max_msg_len);
 		endpoint = &target->endpoint[epid];
 
-		for (tepid = ENDPOINT_MAX; tepid > ENDPOINT0; tepid--) {
+		for (tepid = (ENDPOINT_MAX - 1); tepid > ENDPOINT0; tepid--) {
 			tmp_endpoint = &target->endpoint[tepid];
 			if (tmp_endpoint->service_id == service_id) {
 				tmp_endpoint->service_id = 0;
@@ -125,7 +125,7 @@ static void htc_process_conn_rsp(struct htc_target *target,
 			}
 		}
 
-		if (!tmp_endpoint)
+		if (tepid == ENDPOINT0)
 			return;
 
 		endpoint->service_id = service_id;
@@ -298,7 +298,7 @@ void htc_stop(struct htc_target *target)
 	enum htc_endpoint_id epid;
 	struct htc_endpoint *endpoint;
 
-	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
+	for (epid = ENDPOINT0; epid < ENDPOINT_MAX; epid++) {
 		endpoint = &target->endpoint[epid];
 		if (endpoint->service_id != 0)
 			target->hif->stop(target->hif_dev, endpoint->ul_pipeid);
@@ -310,7 +310,7 @@ void htc_start(struct htc_target *target)
 	enum htc_endpoint_id epid;
 	struct htc_endpoint *endpoint;
 
-	for (epid = ENDPOINT0; epid <= ENDPOINT_MAX; epid++) {
+	for (epid = ENDPOINT0; epid < ENDPOINT_MAX; epid++) {
 		endpoint = &target->endpoint[epid];
 		if (endpoint->service_id != 0)
 			target->hif->start(target->hif_dev,

drivers/net/wireless/ath/ath9k/htc_hst.h

@@ -123,9 +123,6 @@ struct htc_endpoint {
 #define HTC_CONTROL_BUFFER_SIZE	\
 	(HTC_MAX_CONTROL_MESSAGE_LENGTH + sizeof(struct htc_frame_hdr))
 
-#define NUM_CONTROL_BUFFERS 8
-#define HST_ENDPOINT_MAX 8
-
 struct htc_control_buf {
 	struct htc_packet htc_pkt;
 	u8 buf[HTC_CONTROL_BUFFER_SIZE];
@@ -139,7 +136,7 @@ struct htc_target {
 	struct ath9k_htc_priv *drv_priv;
 	struct device *dev;
 	struct ath9k_htc_hif *hif;
-	struct htc_endpoint endpoint[HST_ENDPOINT_MAX];
+	struct htc_endpoint endpoint[ENDPOINT_MAX];
 	struct completion target_wait;
 	struct completion cmd_wait;
 	struct list_head list;