p54: fix oops on faulty devices

This patch fixes an oops when the devices suddenly starts
to receive martian data frames.

bug reference:
http://marc.info/?l=linux-wireless&m=122872280317635&w=2

Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Christian Lamparter 2008-12-09 21:07:50 +01:00 committed by John W. Linville
parent b7a530d82c
commit 59651e8918

View file

@ -540,6 +540,14 @@ static int p54_rx_data(struct ieee80211_hw *dev, struct sk_buff *skb)
size_t header_len = sizeof(*hdr);
u32 tsf32;
/*
* If the device is in a unspecified state we have to
* ignore all data frames. Else we could end up with a
* nasty crash.
*/
if (unlikely(priv->mode == NL80211_IFTYPE_UNSPECIFIED))
return 0;
if (!(hdr->flags & cpu_to_le16(P54_HDR_FLAG_DATA_IN_FCS_GOOD))) {
if (priv->filter_flags & FIF_FCSFAIL)
rx_status.flag |= RX_FLAG_FAILED_FCS_CRC;
@ -608,6 +616,12 @@ void p54_free_skb(struct ieee80211_hw *dev, struct sk_buff *skb)
if (unlikely(!skb || !dev || !skb_queue_len(&priv->tx_queue)))
return;
/*
* don't try to free an already unlinked skb
*/
if (unlikely((!skb->next) || (!skb->prev)))
return;
spin_lock_irqsave(&priv->tx_queue.lock, flags);
info = IEEE80211_SKB_CB(skb);
range = (void *)info->rate_driver_data;
@ -1695,19 +1709,18 @@ static void p54_stop(struct ieee80211_hw *dev)
struct sk_buff *skb;
mutex_lock(&priv->conf_mutex);
priv->mode = NL80211_IFTYPE_UNSPECIFIED;
del_timer(&priv->stats_timer);
p54_free_skb(dev, priv->cached_stats);
priv->cached_stats = NULL;
if (priv->cached_beacon)
p54_tx_cancel(dev, priv->cached_beacon);
priv->stop(dev);
while ((skb = skb_dequeue(&priv->tx_queue)))
kfree_skb(skb);
priv->cached_beacon = NULL;
priv->stop(dev);
priv->tsf_high32 = priv->tsf_low32 = 0;
priv->mode = NL80211_IFTYPE_UNSPECIFIED;
mutex_unlock(&priv->conf_mutex);
}