Subject: [PATCH] appletalk: Fix skb leak when ipddp interface is not loaded

And also do a better job of returning proper NET_{RX,XMIT}_ values.

Based on a patch and suggestions by Mark Smith.

This fixes CVE-2009-2903

Reported-by: Mark Smith <lk-netdev@lk-netdev.nosense.org>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/appletalk/ipddp.c b/drivers/net/appletalk/ipddp.c
index bea87da..aaf14d3 100644 (file)
--- a/drivers/net/appletalk/ipddp.c
+++ b/drivers/net/appletalk/ipddp.c
@@ -177,8 +177,7 @@ static netdev_tx_t ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
        dev->stats.tx_packets++;
        dev->stats.tx_bytes += skb->len;
 
-        if(aarp_send_ddp(rt->dev, skb, &rt->at, NULL) < 0)
-                dev_kfree_skb(skb);
+       aarp_send_ddp(rt->dev, skb, &rt->at, NULL);
 
        spin_unlock(&ipddp_route_lock);
 

diff --git a/net/appletalk/aarp.c b/net/appletalk/aarp.c
index 89f99d3..9d4adfd 100644 (file)
--- a/net/appletalk/aarp.c
+++ b/net/appletalk/aarp.c
@@ -599,7 +599,7 @@ int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb,
 
        /* Non ELAP we cannot do. */
        if (dev->type != ARPHRD_ETHER)
-               return -1;
+               goto free_it;
 
        skb->dev = dev;
        skb->protocol = htons(ETH_P_ATALK);
@@ -634,7 +634,7 @@ int aarp_send_ddp(struct net_device *dev, struct sk_buff *skb,
        if (!a) {
                /* Whoops slipped... good job it's an unreliable protocol 8) */
                write_unlock_bh(&aarp_lock);
-               return -1;
+               goto free_it;
        }
 
        /* Set up the queue */
@@ -663,15 +663,21 @@ out_unlock:
        write_unlock_bh(&aarp_lock);
 
        /* Tell the ddp layer we have taken over for this frame. */
-       return 0;
+       goto sent;
 
 sendit:
        if (skb->sk)
                skb->priority = skb->sk->sk_priority;
-       dev_queue_xmit(skb);
+       if (dev_queue_xmit(skb))
+               goto drop;
 sent:
-       return 1;
+       return NET_XMIT_SUCCESS;
+free_it:
+       kfree_skb(skb);
+drop:
+       return NET_XMIT_DROP;
 }
+EXPORT_SYMBOL(aarp_send_ddp);
 
 /*
  *     An entry in the aarp unresolved queue has become resolved. Send

diff --git a/net/appletalk/ddp.c b/net/appletalk/ddp.c
index 0d42d5d..4a6ff2b 100644 (file)
--- a/net/appletalk/ddp.c
+++ b/net/appletalk/ddp.c
@@ -1270,8 +1270,10 @@ static int handle_ip_over_ddp(struct sk_buff *skb)
        struct net_device_stats *stats;
 
        /* This needs to be able to handle ipddp"N" devices */
-       if (!dev)
-               return -ENODEV;
+       if (!dev) {
+               kfree_skb(skb);
+               return NET_RX_DROP;
+       }
 
        skb->protocol = htons(ETH_P_IP);
        skb_pull(skb, 13);
@@ -1281,8 +1283,7 @@ static int handle_ip_over_ddp(struct sk_buff *skb)
        stats = netdev_priv(dev);
        stats->rx_packets++;
        stats->rx_bytes += skb->len + 13;
-       netif_rx(skb);  /* Send the SKB up to a higher place. */
-       return 0;
+       return netif_rx(skb);  /* Send the SKB up to a higher place. */
 }
 #else
 /* make it easy for gcc to optimize this test out, i.e. kill the code */
@@ -1290,9 +1291,8 @@ static int handle_ip_over_ddp(struct sk_buff *skb)
 #define handle_ip_over_ddp(skb) 0
 #endif
 
-static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
-                              struct ddpehdr *ddp, __u16 len_hops,
-                              int origlen)
+static int atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
+                             struct ddpehdr *ddp, __u16 len_hops, int origlen)
 {
        struct atalk_route *rt;
        struct atalk_addr ta;
@@ -1359,8 +1359,6 @@ static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
                /* 22 bytes - 12 ether, 2 len, 3 802.2 5 snap */
                struct sk_buff *nskb = skb_realloc_headroom(skb, 32);
                kfree_skb(skb);
-               if (!nskb)
-                       goto out;
                skb = nskb;
        } else
                skb = skb_unshare(skb, GFP_ATOMIC);
@@ -1369,12 +1367,16 @@ static void atalk_route_packet(struct sk_buff *skb, struct net_device *dev,
         * If the buffer didn't vanish into the lack of space bitbucket we can
         * send it.
         */
-       if (skb && aarp_send_ddp(rt->dev, skb, &ta, NULL) == -1)
-               goto free_it;
-out:
-       return;
+       if (skb == NULL)
+               goto drop;
+
+       if (aarp_send_ddp(rt->dev, skb, &ta, NULL) == NET_XMIT_DROP)
+               return NET_RX_DROP;
+       return NET_XMIT_SUCCESS;
 free_it:
        kfree_skb(skb);
+drop:
+       return NET_RX_DROP;
 }
 
 /**
@@ -1448,8 +1450,7 @@ static int atalk_rcv(struct sk_buff *skb, struct net_device *dev,
                /* Not ours, so we route the packet via the correct
                 * AppleTalk iface
                 */
-               atalk_route_packet(skb, dev, ddp, len_hops, origlen);
-               return NET_RX_SUCCESS;
+               return atalk_route_packet(skb, dev, ddp, len_hops, origlen);
        }
 
        /* if IP over DDP is not selected this code will be optimized out */
@@ -1655,10 +1656,10 @@ static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
                if (skb2) {
                        loopback = 1;
                        SOCK_DEBUG(sk, "SK %p: send out(copy).\n", sk);
-                       if (aarp_send_ddp(dev, skb2,
-                                         &usat->sat_addr, NULL) == -1)
-                               kfree_skb(skb2);
-                               /* else queued/sent above in the aarp queue */
+                       /*
+                        * If it fails it is queued/sent above in the aarp queue
+                        */
+                       aarp_send_ddp(dev, skb2, &usat->sat_addr, NULL);
                }
        }
 
@@ -1688,9 +1689,10 @@ static int atalk_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr
                    usat = &gsat;
                }
 
-               if (aarp_send_ddp(dev, skb, &usat->sat_addr, NULL) == -1)
-                       kfree_skb(skb);
-               /* else queued/sent above in the aarp queue */
+               /*
+                * If it fails it is queued/sent above in the aarp queue
+                */
+               aarp_send_ddp(dev, skb, &usat->sat_addr, NULL);
        }
        SOCK_DEBUG(sk, "SK %p: Done write (%Zd).\n", sk, len);
 
@@ -1868,7 +1870,6 @@ static struct packet_type ppptalk_packet_type __read_mostly = {
 static unsigned char ddp_snap_id[] = { 0x08, 0x00, 0x07, 0x80, 0x9B };
 
 /* Export symbols for use by drivers when AppleTalk is a module */
-EXPORT_SYMBOL(aarp_send_ddp);
 EXPORT_SYMBOL(atrtr_get_dev);
 EXPORT_SYMBOL(atalk_find_dev_addr);