From aa2dc6b529d781a375f7ad3185198f6315865b06 Mon Sep 17 00:00:00 2001 From: Shanyu Zhao Date: Wed, 28 Jul 2010 13:40:39 -0700 Subject: [PATCH] iwlwifi: avoid race condition in channel change When iwl_mac_config() is called by mac80211, the channel pointer hw->conf->channel can potentially change, resulting in mismatch band and channel number when configuring RXON command. To avoid this situation, save the channel pointer in local variables and validate the channel before using it. Note that priv->mutex is locked during the whole function so the local variables are safe. Same change is applied to iwl_mac_channel_switch() since basically it copies code from iwl_mac_config(). Also removed an outdated comment in the flow. Signed-off-by: Shanyu Zhao Signed-off-by: Wey-Yi Guy --- drivers/net/wireless/iwlwifi/iwl-agn.c | 14 ++++++-------- drivers/net/wireless/iwlwifi/iwl-core.c | 14 ++++++-------- 2 files changed, 12 insertions(+), 16 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c index eecfec7c4063..61ecd180982e 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn.c @@ -3632,6 +3632,7 @@ static void iwl_mac_channel_switch(struct ieee80211_hw *hw, struct iwl_priv *priv = hw->priv; const struct iwl_channel_info *ch_info; struct ieee80211_conf *conf = &hw->conf; + struct ieee80211_channel *channel = ch_switch->channel; struct iwl_ht_config *ht_conf = &priv->current_ht_config; u16 ch; unsigned long flags = 0; @@ -3655,10 +3656,10 @@ static void iwl_mac_channel_switch(struct ieee80211_hw *hw, mutex_lock(&priv->mutex); if (priv->cfg->ops->lib->set_channel_switch) { - ch = ch_switch->channel->hw_value; + ch = channel->hw_value; if (le16_to_cpu(priv->active_rxon.channel) != ch) { ch_info = iwl_get_channel_info(priv, - conf->channel->band, + channel->band, ch); if (!is_channel_valid(ch_info)) { IWL_DEBUG_MAC80211(priv, "invalid channel\n"); @@ -3687,15 +3688,12 @@ static void iwl_mac_channel_switch(struct ieee80211_hw *hw, } else ht_conf->is_40mhz = false; - /* if we are switching from ht to 2.4 clear flags - * from any ht related info since 2.4 does not - * support ht */ - if ((le16_to_cpu(priv->staging_rxon.channel) != ch)) + if (le16_to_cpu(priv->staging_rxon.channel) != ch) priv->staging_rxon.flags = 0; - iwl_set_rxon_channel(priv, conf->channel); + iwl_set_rxon_channel(priv, channel); iwl_set_rxon_ht(priv, ht_conf); - iwl_set_flags_for_band(priv, conf->channel->band, + iwl_set_flags_for_band(priv, channel->band, priv->vif); spin_unlock_irqrestore(&priv->lock, flags); diff --git a/drivers/net/wireless/iwlwifi/iwl-core.c b/drivers/net/wireless/iwlwifi/iwl-core.c index dc29844cce1f..39aea7545603 100644 --- a/drivers/net/wireless/iwlwifi/iwl-core.c +++ b/drivers/net/wireless/iwlwifi/iwl-core.c @@ -1992,6 +1992,7 @@ int iwl_mac_config(struct ieee80211_hw *hw, u32 changed) struct iwl_priv *priv = hw->priv; const struct iwl_channel_info *ch_info; struct ieee80211_conf *conf = &hw->conf; + struct ieee80211_channel *channel = conf->channel; struct iwl_ht_config *ht_conf = &priv->current_ht_config; unsigned long flags = 0; int ret = 0; @@ -2001,7 +2002,7 @@ int iwl_mac_config(struct ieee80211_hw *hw, u32 changed) mutex_lock(&priv->mutex); IWL_DEBUG_MAC80211(priv, "enter to channel %d changed 0x%X\n", - conf->channel->hw_value, changed); + channel->hw_value, changed); if (unlikely(!priv->cfg->mod_params->disable_hw_scan && test_bit(STATUS_SCANNING, &priv->status))) { @@ -2032,8 +2033,8 @@ int iwl_mac_config(struct ieee80211_hw *hw, u32 changed) if (scan_active) goto set_ch_out; - ch = conf->channel->hw_value; - ch_info = iwl_get_channel_info(priv, conf->channel->band, ch); + ch = channel->hw_value; + ch_info = iwl_get_channel_info(priv, channel->band, ch); if (!is_channel_valid(ch_info)) { IWL_DEBUG_MAC80211(priv, "leave - invalid channel\n"); ret = -EINVAL; @@ -2064,16 +2065,13 @@ int iwl_mac_config(struct ieee80211_hw *hw, u32 changed) * from BSS config in iwl_ht_conf */ ht_conf->ht_protection = IEEE80211_HT_OP_MODE_PROTECTION_NONE; - /* if we are switching from ht to 2.4 clear flags - * from any ht related info since 2.4 does not - * support ht */ if ((le16_to_cpu(priv->staging_rxon.channel) != ch)) priv->staging_rxon.flags = 0; - iwl_set_rxon_channel(priv, conf->channel); + iwl_set_rxon_channel(priv, channel); iwl_set_rxon_ht(priv, ht_conf); - iwl_set_flags_for_band(priv, conf->channel->band, priv->vif); + iwl_set_flags_for_band(priv, channel->band, priv->vif); spin_unlock_irqrestore(&priv->lock, flags); if (priv->cfg->ops->lib->update_bcast_station) -- 2.39.5