rtlwifi: Fix possible NULL dereference

In drivers/net/wireless/rtlwifi/pci.c::_rtl_pci_rx_interrupt() we call
dev_alloc_skb(), which may fail and return NULL, but we do not check the
returned value against NULL before dereferencing the returned pointer.
This may lead to a NULL pointer dereference which means we'll crash - not
good.

In a separate call to dev_alloc_skb(), the debug level is changed so that
the failure message will always be logged.

Signed-off-by: Jesper Juhl <jj@chaosbits.net>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/net/wireless/rtlwifi/pci.c b/drivers/net/wireless/rtlwifi/pci.c
index 0fa36aa6701a..1758d4463247 100644
--- a/drivers/net/wireless/rtlwifi/pci.c
+++ b/drivers/net/wireless/rtlwifi/pci.c
@@ -619,6 +619,13 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
                                         struct sk_buff *uskb = NULL;
                                         u8 *pdata;
                                         uskb = dev_alloc_skb(skb->len + 128);
+                                        if (!uskb) {
+                                                RT_TRACE(rtlpriv,
+                                                        (COMP_INTR | COMP_RECV),
+                                                        DBG_EMERG,
+                                                        ("can't alloc rx skb\n"));
+                                                goto done;
+                                        }
                                         memcpy(IEEE80211_SKB_RXCB(uskb),
                                                         &rx_status,
                                                         sizeof(rx_status));
@@ -641,7 +648,7 @@ static void _rtl_pci_rx_interrupt(struct ieee80211_hw *hw)
                         new_skb = dev_alloc_skb(rtlpci->rxbuffersize);
                         if (unlikely(!new_skb)) {
                                 RT_TRACE(rtlpriv, (COMP_INTR | COMP_RECV),
-                                         DBG_DMESG,
+                                         DBG_EMERG,
                                          ("can't alloc skb for rx\n"));
                                 goto done;
                         }
@@ -1066,9 +1073,9 @@ static int _rtl_pci_init_rx_ring(struct ieee80211_hw *hw)
                         struct sk_buff *skb =
                             dev_alloc_skb(rtlpci->rxbuffersize);
                         u32 bufferaddress;
-                        entry = &rtlpci->rx_ring[rx_queue_idx].desc[i];
                         if (!skb)
                                 return 0;
+                        entry = &rtlpci->rx_ring[rx_queue_idx].desc[i];
 
                         /*skb->dev = dev; */