Return-path: Received: from mail-qg0-f65.google.com ([209.85.192.65]:36829 "EHLO mail-qg0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753212AbcFJMy7 (ORCPT ); Fri, 10 Jun 2016 08:54:59 -0400 Received: by mail-qg0-f65.google.com with SMTP id k43so5177929qgk.3 for ; Fri, 10 Jun 2016 05:54:58 -0700 (PDT) From: Bob Copeland To: linux-wireless@vger.kernel.org Cc: ath10k@lists.infradead.org, Bob Copeland Subject: [PATCH] ath10k: fix potential null dereference bugs Date: Fri, 10 Jun 2016 08:52:44 -0400 Message-Id: <1465563164-783-1-git-send-email-me@bobcopeland.com> (sfid-20160610_145504_275762_DD202546) Sender: linux-wireless-owner@vger.kernel.org List-ID: Smatch warns about a number of cases in ath10k where a pointer is null-checked after it has already been dereferenced, in code involving ath10k private virtual interface pointers. Fix these by making the dereference happen later. Addresses the following smatch warnings: drivers/net/wireless/ath/ath10k/mac.c:3651 ath10k_mac_txq_init() warn: variable dereferenced before check 'txq' (see line 3649) drivers/net/wireless/ath/ath10k/mac.c:3664 ath10k_mac_txq_unref() warn: variable dereferenced before check 'txq' (see line 3659) drivers/net/wireless/ath/ath10k/htt_tx.c:70 __ath10k_htt_tx_txq_recalc() warn: variable dereferenced before check 'txq->sta' (see line 52) drivers/net/wireless/ath/ath10k/htt_tx.c:740 ath10k_htt_tx_get_vdev_id() warn: variable dereferenced before check 'cb->vif' (see line 736) drivers/net/wireless/ath/ath10k/txrx.c:86 ath10k_txrx_tx_unref() warn: variable dereferenced before check 'txq' (see line 84) drivers/net/wireless/ath/ath10k/wmi.c:1837 ath10k_wmi_op_gen_mgmt_tx() warn: variable dereferenced before check 'cb->vif' (see line 1825) Signed-off-by: Bob Copeland --- Although I glanced at a few cases, by and large I didn't check whether the if() tests were correct but assumed they were. Also, I only compile-tested this. drivers/net/wireless/ath/ath10k/htt_tx.c | 15 +++++++++------ drivers/net/wireless/ath/ath10k/mac.c | 6 ++++-- drivers/net/wireless/ath/ath10k/txrx.c | 5 +++-- drivers/net/wireless/ath/ath10k/wmi.c | 8 +++++--- 4 files changed, 21 insertions(+), 13 deletions(-) diff --git a/drivers/net/wireless/ath/ath10k/htt_tx.c b/drivers/net/wireless/ath/ath10k/htt_tx.c index 6269c61..dfcc43d 100644 --- a/drivers/net/wireless/ath/ath10k/htt_tx.c +++ b/drivers/net/wireless/ath/ath10k/htt_tx.c @@ -49,7 +49,7 @@ static void __ath10k_htt_tx_txq_recalc(struct ieee80211_hw *hw, struct ieee80211_txq *txq) { struct ath10k *ar = hw->priv; - struct ath10k_sta *arsta = (void *)txq->sta->drv_priv; + struct ath10k_sta *arsta; struct ath10k_vif *arvif = (void *)txq->vif->drv_priv; unsigned long frame_cnt; unsigned long byte_cnt; @@ -67,10 +67,12 @@ static void __ath10k_htt_tx_txq_recalc(struct ieee80211_hw *hw, if (ar->htt.tx_q_state.mode != HTT_TX_MODE_SWITCH_PUSH_PULL) return; - if (txq->sta) + if (txq->sta) { + arsta = (void *)txq->sta->drv_priv; peer_id = arsta->peer_id; - else + } else { peer_id = arvif->peer_id; + } tid = txq->tid; bit = BIT(peer_id % 32); @@ -733,13 +735,14 @@ static u8 ath10k_htt_tx_get_vdev_id(struct ath10k *ar, struct sk_buff *skb) { struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); struct ath10k_skb_cb *cb = ATH10K_SKB_CB(skb); - struct ath10k_vif *arvif = (void *)cb->vif->drv_priv; + struct ath10k_vif *arvif; if (info->flags & IEEE80211_TX_CTL_TX_OFFCHAN) return ar->scan.vdev_id; - else if (cb->vif) + else if (cb->vif) { + arvif = (void *)cb->vif->drv_priv; return arvif->vdev_id; - else if (ar->monitor_started) + } else if (ar->monitor_started) return ar->monitor_vdev_id; else return 0; diff --git a/drivers/net/wireless/ath/ath10k/mac.c b/drivers/net/wireless/ath/ath10k/mac.c index 6dd1d26..4eee4b9 100644 --- a/drivers/net/wireless/ath/ath10k/mac.c +++ b/drivers/net/wireless/ath/ath10k/mac.c @@ -3646,17 +3646,18 @@ void ath10k_mgmt_over_wmi_tx_work(struct work_struct *work) static void ath10k_mac_txq_init(struct ieee80211_txq *txq) { - struct ath10k_txq *artxq = (void *)txq->drv_priv; + struct ath10k_txq *artxq; if (!txq) return; + artxq = (void *)txq->drv_priv; INIT_LIST_HEAD(&artxq->list); } static void ath10k_mac_txq_unref(struct ath10k *ar, struct ieee80211_txq *txq) { - struct ath10k_txq *artxq = (void *)txq->drv_priv; + struct ath10k_txq *artxq; struct ath10k_skb_cb *cb; struct sk_buff *msdu; int msdu_id; @@ -3664,6 +3665,7 @@ static void ath10k_mac_txq_unref(struct ath10k *ar, struct ieee80211_txq *txq) if (!txq) return; + artxq = (void *)txq->drv_priv; spin_lock_bh(&ar->txqs_lock); if (!list_empty(&artxq->list)) list_del_init(&artxq->list); diff --git a/drivers/net/wireless/ath/ath10k/txrx.c b/drivers/net/wireless/ath/ath10k/txrx.c index 576e7c4..9f17863 100644 --- a/drivers/net/wireless/ath/ath10k/txrx.c +++ b/drivers/net/wireless/ath/ath10k/txrx.c @@ -81,10 +81,11 @@ int ath10k_txrx_tx_unref(struct ath10k_htt *htt, skb_cb = ATH10K_SKB_CB(msdu); txq = skb_cb->txq; - artxq = (void *)txq->drv_priv; - if (txq) + if (txq) { + artxq = (void *)txq->drv_priv; artxq->num_fw_queued--; + } ath10k_htt_tx_free_msdu_id(htt, tx_done->msdu_id); ath10k_htt_tx_dec_pending(htt); diff --git a/drivers/net/wireless/ath/ath10k/wmi.c b/drivers/net/wireless/ath/ath10k/wmi.c index 2c30032..60f78a6 100644 --- a/drivers/net/wireless/ath/ath10k/wmi.c +++ b/drivers/net/wireless/ath/ath10k/wmi.c @@ -1822,7 +1822,7 @@ static struct sk_buff * ath10k_wmi_op_gen_mgmt_tx(struct ath10k *ar, struct sk_buff *msdu) { struct ath10k_skb_cb *cb = ATH10K_SKB_CB(msdu); - struct ath10k_vif *arvif = (void *)cb->vif->drv_priv; + struct ath10k_vif *arvif; struct wmi_mgmt_tx_cmd *cmd; struct ieee80211_hdr *hdr; struct sk_buff *skb; @@ -1834,10 +1834,12 @@ ath10k_wmi_op_gen_mgmt_tx(struct ath10k *ar, struct sk_buff *msdu) hdr = (struct ieee80211_hdr *)msdu->data; fc = le16_to_cpu(hdr->frame_control); - if (cb->vif) + if (cb->vif) { + arvif = (void *)cb->vif->drv_priv; vdev_id = arvif->vdev_id; - else + } else { vdev_id = 0; + } if (WARN_ON_ONCE(!ieee80211_is_mgmt(hdr->frame_control))) return ERR_PTR(-EINVAL); -- 2.1.4