qcacld-3.0: Fix null pointer dereference in __lim_process_sme_join_req

Add input validation code in function __lim_process_sme_join_req
to make sure "mac_ctx" and "msg_buf" are not null.

This input validation will prevent any possible null pointer dereference
issues.

Change-Id: Ib12ffbe1d6fdcd841fd10158b59d648d0b94aa47
CRs-Fixed: 1042968

core/mac/src/pe/lim/lim_process_sme_req_messages.c

@@ -1610,6 +1610,12 @@ __lim_process_sme_join_req(tpAniSirGlobal mac_ctx, uint32_t *msg_buf)
 	tSirBssDescription *bss_desc;
 	struct vdev_type_nss *vdev_type_nss;
 
+	if (!mac_ctx || !msg_buf) {
+		QDF_TRACE(QDF_MODULE_ID_PE, QDF_TRACE_LEVEL_ERROR,
+			  FL("JOIN REQ with invalid data"));
+		return;
+	}
+
 /* FEATURE_WLAN_DIAG_SUPPORT */
 #ifdef FEATURE_WLAN_DIAG_SUPPORT_LIM
 	/*