iwlwifi: prevent read outside array bounds

With EDCA and HCCA we have 16 potential tid values. This is accommodated by
mac80211, but iwlwifi only supports EDCA. With this implementation it is
thus possible for mac80211 to request a tid that will cause iwlwifi to read
outside array bounds. A similar problem exists if traffic is received in an
unsupported category.

We add error checking to catch these situations.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
index 2133155..1bd7cd4 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-rs.c
@@ -332,6 +332,9 @@
 	} else
 		return MAX_TID_COUNT;
 
+	if (unlikely(tid >= TID_MAX_LOAD_COUNT))
+		return MAX_TID_COUNT;
+
 	tl = &lq_data->load[tid];
 
 	curr_time -= curr_time % TID_ROUND_VALUE;
diff --git a/drivers/net/wireless/iwlwifi/iwl-tx.c b/drivers/net/wireless/iwlwifi/iwl-tx.c
index 9b76bd4..7686fc7 100644
--- a/drivers/net/wireless/iwlwifi/iwl-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-tx.c
@@ -745,6 +745,8 @@
 	if (ieee80211_is_data_qos(fc)) {
 		qc = ieee80211_get_qos_ctl(hdr);
 		tid = qc[0] & IEEE80211_QOS_CTL_TID_MASK;
+		if (unlikely(tid >= MAX_TID_COUNT))
+			goto drop_unlock;
 		seq_number = priv->stations[sta_id].tid[tid].seq_number;
 		seq_number &= IEEE80211_SCTL_SEQ;
 		hdr->seq_ctrl = hdr->seq_ctrl &
@@ -1238,6 +1240,9 @@
 		return -EINVAL;
 	}
 
+	if (unlikely(tid >= MAX_TID_COUNT))
+		return -EINVAL;
+
 	if (likely(tid < ARRAY_SIZE(default_tid_to_tx_fifo)))
 		tx_fifo_id = default_tid_to_tx_fifo[tid];
 	else
diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index e617411..f339c5b 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -544,6 +544,8 @@
 	if (ieee80211_is_data_qos(fc)) {
 		qc = ieee80211_get_qos_ctl(hdr);
 		tid = qc[0] & IEEE80211_QOS_CTL_TID_MASK;
+		if (unlikely(tid >= MAX_TID_COUNT))
+			goto drop;
 		seq_number = priv->stations[sta_id].tid[tid].seq_number &
 				IEEE80211_SCTL_SEQ;
 		hdr->seq_ctrl = cpu_to_le16(seq_number) |