qcacld-3.0: Fix buffer overflow in wma radio_tx_power_level_stats handler

In function wma_unified_radio_tx_power_level_stats_event_handler,
power_level_offset is received from the FW and is used to memcpy data
from FW to local tx_time_per_power_level for num_tx_power_levels length.
However tx_time_per_power_level is allocated only for
total_num_tx_power_levels length.
If the power_level_offset is greater than total_num_tx_power_levels, then
a buffer overwrite would occur.

Add sanity check to make sure power_level_offset does not exceed
total_num_tx_power_levels

Change-Id: Ia363512ee35bb0e30b137c20bf092238c2e356da
CRs-Fixed: 2149501

core/wma/src/wma_utils.c

@@ -1484,9 +1484,9 @@ static int wma_unified_radio_tx_power_level_stats_event_handler(void *handle,
 	    sizeof(*fixed_param)) / sizeof(uint32_t))) {
 		WMA_LOGE("%s: excess tx_power buffers:%d", __func__,
 			fixed_param->num_tx_power_levels);
-		QDF_ASSERT(0);
 		return -EINVAL;
 	}
+
 	rs_results = (tSirWifiRadioStat *) &link_stats_results->results[0] +
 							 fixed_param->radio_id;
 	tx_power_level_values = (uint8_t *) param_tlvs->tx_time_per_power_level;
@@ -1498,6 +1498,18 @@ static int wma_unified_radio_tx_power_level_stats_event_handler(void *handle,
 		goto post_stats;
 	}
 
+	if ((fixed_param->power_level_offset >
+	    rs_results->total_num_tx_power_levels) ||
+	    (fixed_param->num_tx_power_levels >
+	    rs_results->total_num_tx_power_levels -
+	    fixed_param->power_level_offset)) {
+		WMA_LOGE("%s: Invalid offset %d total_num %d num %d",
+			 __func__, fixed_param->power_level_offset,
+			 rs_results->total_num_tx_power_levels,
+			 fixed_param->num_tx_power_levels);
+		return -EINVAL;
+	}
+
 	if (!rs_results->tx_time_per_power_level) {
 		rs_results->tx_time_per_power_level = qdf_mem_malloc(
 				sizeof(uint32_t) *