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>

diff --git a/drivers/net/wireless/rtlwifi/pci.c b/drivers/net/wireless/rtlwifi/pci.c
index 0fa36aa..1758d44 100644 (file)
--- 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; */