[PATCH] wifi: iwlegacy: Check rate_idx range after addition

[Stanislaw Gruszka <stf_xl@wp.pl>]

Move rate_idx range check after we add IL_FIRST_OFDM_RATE for it
for 5GHz band.

Additionally use ">= RATE_COUNT" check instead of "> RATE_COUNT_LEGACY"
to avoid possible reviewers and static code analyzers confusion about
size of il_rate array.

Reported-by: Fedor Pchelkin <pchelkin@ispras.ru>
Reported-by: Alexei Safin <a.safin@rosa.ru>
Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
---
 drivers/net/wireless/intel/iwlegacy/4965-mac.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlegacy/4965-mac.c b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
index dc8c408902e6..2294ea43b4c7 100644
--- a/drivers/net/wireless/intel/iwlegacy/4965-mac.c
+++ b/drivers/net/wireless/intel/iwlegacy/4965-mac.c
@@ -1567,16 +1567,19 @@ il4965_tx_cmd_build_rate(struct il_priv *il,
 	/**
 	 * If the current TX rate stored in mac80211 has the MCS bit set, it's
 	 * not really a TX rate.  Thus, we use the lowest supported rate for
-	 * this band.  Also use the lowest supported rate if the stored rate
-	 * idx is invalid.
+	 * this band.
 	 */
 	rate_idx = info->control.rates[0].idx;
-	if ((info->control.rates[0].flags & IEEE80211_TX_RC_MCS) || rate_idx < 0
-	    || rate_idx > RATE_COUNT_LEGACY)
+	if (info->control.rates[0].flags & IEEE80211_TX_RC_MCS)
 		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
-	/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
-	if (info->band == NL80211_BAND_5GHZ)
+	else if (info->band == NL80211_BAND_5GHZ)
+		/* For 5 GHZ band, remap mac80211 rate indices into driver indices */
 		rate_idx += IL_FIRST_OFDM_RATE;
+
+	/* Use the lowest supported rate if the stored rate idx is invalid. */
+	if (rate_idx < 0 || rate_idx >= RATE_COUNT)
+		rate_idx = rate_lowest_index(&il->bands[info->band], sta);
+
 	/* Get PLCP rate for tx_cmd->rate_n_flags */
 	rate_plcp = il_rates[rate_idx].plcp;
 	/* Zero out flags for this packet */
-- 
2.25.4