[PATCH 5/5] iwlwifi: mvm: check if mac80211_queue is valid in iwl_mvm_disable_txq

[Luca Coelho]

From: Luca Coelho <luciano.coe...@intel.com>

Sometimes iwl_mvm_disable_txq() may be called with mac80211_queue ==
IEEE80211_INVAL_HW_QUEUE, and this would cause us to use BIT(0xFF)
which is way too large for the u16 we used to store it in
hw_queue_to_mac820211.  If this happens the following UBSAN warning
will be generated:

[  167.185167] UBSAN: Undefined behaviour in 
drivers/net/wireless/intel/iwlwifi/mvm/utils.c:838:5
[  167.185171] shift exponent 255 is too large for 64-bit type 'long unsigned 
int'

Fix that by checking that it is not IEEE80211_INVAL_HW_QUEUE and,
while at it, add a warning if the queue number is larger than
IEEE80211_MAX_QUEUES.

Fixes: 34e10860ae8d ("iwlwifi: mvm: remove references to queue_info in new TX 
path")
Reported-by: Paul Menzel <pmenzel+linux-wirel...@molgen.mpg.de>
Signed-off-by: Luca Coelho <luciano.coe...@intel.com>
---
 drivers/net/wireless/intel/iwlwifi/mvm/utils.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/intel/iwlwifi/mvm/utils.c 
b/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
index d65e1db7c097..70f8b8eb6117 100644
--- a/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
+++ b/drivers/net/wireless/intel/iwlwifi/mvm/utils.c
@@ -800,12 +800,19 @@ int iwl_mvm_disable_txq(struct iwl_mvm *mvm, int queue, 
int mac80211_queue,
                .scd_queue = queue,
                .action = SCD_CFG_DISABLE_QUEUE,
        };
-       bool remove_mac_queue = true;
+       bool remove_mac_queue = mac80211_queue != IEEE80211_INVAL_HW_QUEUE;
        int ret;
 
+       if (WARN_ON(remove_mac_queue && mac80211_queue >= IEEE80211_MAX_QUEUES))
+               return -EINVAL;
+
        if (iwl_mvm_has_new_tx_api(mvm)) {
                spin_lock_bh(&mvm->queue_info_lock);
-               mvm->hw_queue_to_mac80211[queue] &= ~BIT(mac80211_queue);
+
+               if (remove_mac_queue)
+                       mvm->hw_queue_to_mac80211[queue] &=
+                               ~BIT(mac80211_queue);
+
                spin_unlock_bh(&mvm->queue_info_lock);
 
                iwl_trans_txq_free(mvm->trans, queue);
-- 
2.15.1