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Date: Mon, 4 Jan 2016 20:30:58 -0600 From: Larry Finger <Larry.Finger@...inger.net> To: gregkh@...uxfoundation.org Cc: netdev@...r.kernel.org, devel@...verdev.osuosl.org, Larry Finger <Larry.Finger@...inger.net>, Yong Shi <brave_shi@....com> Subject: [PATCH] staging: r8192U: Fix check pointer after usage problem In routine rtl8192_tx_isr(), pointer skb is dereferenced before it is checked for NULL. This patch has only been compile-tested, as I do not have the hardware. This problem was reported at https://bugzilla.kernel.org/show_bug.cgi?id=109951. Fixes: bugzilla.kernel.org: #109951 Reported-by: Yong Shi <brave_shi@....com> Signed-off-by: Larry Finger <Larry.Finger@...inger.net> Cc: Yong Shi <brave_shi@....com> --- drivers/staging/rtl8192u/r8192U_core.c | 21 +++++++++++++-------- 1 file changed, 13 insertions(+), 8 deletions(-) diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c index f4a4eae..87093c0 100644 --- a/drivers/staging/rtl8192u/r8192U_core.c +++ b/drivers/staging/rtl8192u/r8192U_core.c @@ -1092,10 +1092,17 @@ static int rtl8192_hard_start_xmit(struct sk_buff *skb, struct net_device *dev) static void rtl8192_tx_isr(struct urb *tx_urb) { struct sk_buff *skb = (struct sk_buff *)tx_urb->context; - struct net_device *dev = (struct net_device *)(skb->cb); + struct net_device *dev; struct r8192_priv *priv = NULL; - cb_desc *tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); - u8 queue_index = tcb_desc->queue_index; + cb_desc *tcb_desc; + u8 queue_index; + + if (!skb) + return; + + dev = (struct net_device *)(skb->cb); + tcb_desc = (cb_desc *)(skb->cb + MAX_DEV_ADDR_SIZE); + queue_index = tcb_desc->queue_index; priv = ieee80211_priv(dev); @@ -1113,11 +1120,9 @@ static void rtl8192_tx_isr(struct urb *tx_urb) } /* free skb and tx_urb */ - if (skb != NULL) { - dev_kfree_skb_any(skb); - usb_free_urb(tx_urb); - atomic_dec(&priv->tx_pending[queue_index]); - } + dev_kfree_skb_any(skb); + usb_free_urb(tx_urb); + atomic_dec(&priv->tx_pending[queue_index]); /* * Handle HW Beacon: -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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