[PATCH] staging: r8192U: Fix check pointer after usage problem
From: Larry Finger <hidden>
Date: 2016-01-05 02:31:15
Subsystem:
staging subsystem, the rest · Maintainers:
Greg Kroah-Hartman, Linus Torvalds
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 <redacted> Signed-off-by: Larry Finger <redacted> Cc: Yong Shi <redacted> --- 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