wifi: iwlwifi: add a few rate index validity checks

Validate index before access iwl_rate_mcs to keep rate->index
inside the valid boundaries. Use MCS_0_INDEX if index is less
than MCS_0_INDEX and MCS_9_INDEX if index is greater then
MCS_9_INDEX.
Signed-off-by: Anjaneyulu <pagadala.yesu.anjaneyulu@intel.com>
Signed-off-by: Gregory Greenman <gregory.greenman@intel.com>
Link: https://lore.kernel.org/r/20230614123447.79f16b3aef32.If1137f894775d6d07b78cbf3a6163ffce6399507@changeidSigned-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/intel/iwlwifi/dvm/rs.c

@@ -2,7 +2,7 @@
 /******************************************************************************
  *
  * Copyright(c) 2005 - 2014 Intel Corporation. All rights reserved.
- * Copyright (C) 2019 - 2020, 2022 Intel Corporation
+ * Copyright (C) 2019 - 2020, 2022 - 2023 Intel Corporation
  *****************************************************************************/
 #include <linux/kernel.h>
 #include <linux/skbuff.h>
@@ -125,7 +125,7 @@ static int iwl_hwrate_to_plcp_idx(u32 rate_n_flags)
 				return idx;
 	}
 
-	return -1;
+	return IWL_RATE_INVALID;
 }
 
 static void rs_rate_scale_perform(struct iwl_priv *priv,
@@ -3146,7 +3146,10 @@ static ssize_t rs_sta_dbgfs_scale_table_read(struct file *file,
 	for (i = 0; i < LINK_QUAL_MAX_RETRY_NUM; i++) {
 		index = iwl_hwrate_to_plcp_idx(
 			le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags));
-		if (is_legacy(tbl->lq_type)) {
+		if (index == IWL_RATE_INVALID) {
+			desc += sprintf(buff + desc, " rate[%d] 0x%X invalid rate\n",
+				i, le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags));
+		} else if (is_legacy(tbl->lq_type)) {
 			desc += sprintf(buff+desc, " rate[%d] 0x%X %smbps\n",
 				i, le32_to_cpu(lq_sta->lq.rs_table[i].rate_n_flags),
 				iwl_rate_mcs[index].mbps);

drivers/net/wireless/intel/iwlwifi/mvm/rs.c

 // SPDX-License-Identifier: GPL-2.0-only
 /******************************************************************************
  *
- * Copyright(c) 2005 - 2014, 2018 - 2022 Intel Corporation. All rights reserved.
+ * Copyright(c) 2005 - 2014, 2018 - 2023 Intel Corporation. All rights reserved.
  * Copyright(c) 2013 - 2015 Intel Mobile Communications GmbH
  * Copyright(c) 2016 - 2017 Intel Deutschland GmbH
  *****************************************************************************/
@@ -1070,10 +1070,13 @@ static void rs_get_lower_rate_down_column(struct iwl_lq_sta *lq_sta,
 
 		rate->bw = RATE_MCS_CHAN_WIDTH_20;
 
-		WARN_ON_ONCE(rate->index < IWL_RATE_MCS_0_INDEX ||
-			     rate->index > IWL_RATE_MCS_9_INDEX);
+		if (WARN_ON_ONCE(rate->index < IWL_RATE_MCS_0_INDEX))
+			rate->index = rs_ht_to_legacy[IWL_RATE_MCS_0_INDEX];
+		else if (WARN_ON_ONCE(rate->index > IWL_RATE_MCS_9_INDEX))
+			rate->index = rs_ht_to_legacy[IWL_RATE_MCS_9_INDEX];
+		else
+			rate->index = rs_ht_to_legacy[rate->index];
 
-		rate->index = rs_ht_to_legacy[rate->index];
 		rate->ldpc = false;
 	} else {
 		/* Downgrade to SISO with same MCS if in MIMO  */