appletalk: Add proper locking around IPDDP routing table.

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/appletalk/ipddp.c

@@ -39,6 +39,7 @@
 static const char version[] = KERN_INFO "ipddp.c:v0.01 8/28/97 Bradford W. Johnson <johns393@maroon.tc.umn.edu>\n";
 
 static struct ipddp_route *ipddp_route_list;
+static DEFINE_SPINLOCK(ipddp_route_lock);
 
 #ifdef CONFIG_IPDDP_ENCAP
 static int ipddp_mode = IPDDP_ENCAP;
@@ -50,7 +51,7 @@ static int ipddp_mode = IPDDP_DECAP;
 static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev);
 static int ipddp_create(struct ipddp_route *new_rt);
 static int ipddp_delete(struct ipddp_route *rt);
-static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt);
+static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt);
 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd);
 
 static const struct net_device_ops ipddp_netdev_ops = {
@@ -119,6 +120,8 @@ static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
         struct ipddp_route *rt;
         struct atalk_addr *our_addr;
 
+	spin_lock(&ipddp_route_lock);
+
 	/*
          * Find appropriate route to use, based only on IP number.
          */
@@ -127,8 +130,10 @@ static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
                 if(rt->ip == paddr)
                         break;
         }
-        if(rt == NULL)
+        if(rt == NULL) {
+		spin_unlock(&ipddp_route_lock);
                 return 0;
+	}
 
         our_addr = atalk_find_dev_addr(rt->dev);
 
@@ -174,6 +179,8 @@ static int ipddp_xmit(struct sk_buff *skb, struct net_device *dev)
         if(aarp_send_ddp(rt->dev, skb, &rt->at, NULL) < 0)
                 dev_kfree_skb(skb);
 
+	spin_unlock(&ipddp_route_lock);
+
         return 0;
 }
 
@@ -196,7 +203,9 @@ static int ipddp_create(struct ipddp_route *new_rt)
                 return -ENETUNREACH;
         }
 
-	if (ipddp_find_route(rt)) {
+	spin_lock_bh(&ipddp_route_lock);
+	if (__ipddp_find_route(rt)) {
+		spin_unlock_bh(&ipddp_route_lock);
 		kfree(rt);
 		return -EEXIST;
 	}
@@ -204,6 +213,8 @@ static int ipddp_create(struct ipddp_route *new_rt)
         rt->next = ipddp_route_list;
         ipddp_route_list = rt;
 
+	spin_unlock_bh(&ipddp_route_lock);
+
         return 0;
 }
 
@@ -216,6 +227,7 @@ static int ipddp_delete(struct ipddp_route *rt)
         struct ipddp_route **r = &ipddp_route_list;
         struct ipddp_route *tmp;
 
+	spin_lock_bh(&ipddp_route_lock);
         while((tmp = *r) != NULL)
         {
                 if(tmp->ip == rt->ip
@@ -223,19 +235,21 @@ static int ipddp_delete(struct ipddp_route *rt)
                         && tmp->at.s_node == rt->at.s_node)
                 {
                         *r = tmp->next;
+			spin_unlock_bh(&ipddp_route_lock);
                         kfree(tmp);
                         return 0;
                 }
                 r = &tmp->next;
         }
 
+	spin_unlock_bh(&ipddp_route_lock);
         return (-ENOENT);
 }
 
 /*
  * Find a routing entry, we only return a FULL match
  */
-static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt)
+static struct ipddp_route* __ipddp_find_route(struct ipddp_route *rt)
 {
         struct ipddp_route *f;
 
@@ -253,7 +267,7 @@ static struct ipddp_route* ipddp_find_route(struct ipddp_route *rt)
 static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
 {
         struct ipddp_route __user *rt = ifr->ifr_data;
-        struct ipddp_route rcp;
+        struct ipddp_route rcp, rcp2, *rp;
 
         if(!capable(CAP_NET_ADMIN))
                 return -EPERM;
@@ -267,9 +281,19 @@ static int ipddp_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
                         return (ipddp_create(&rcp));
 
                 case SIOCFINDIPDDPRT:
-                        if(copy_to_user(rt, ipddp_find_route(&rcp), sizeof(struct ipddp_route)))
+			spin_lock_bh(&ipddp_route_lock);
+			rp = __ipddp_find_route(&rcp);
+			if (rp)
+				memcpy(&rcp2, rp, sizeof(rcp2));
+			spin_unlock_bh(&ipddp_route_lock);
+
+			if (rp) {
+				if (copy_to_user(rt, &rcp2,
+						 sizeof(struct ipddp_route)))
 					return -EFAULT;
 				return 0;
+			} else
+				return -ENOENT;
 
                 case SIOCDELIPDDPRT:
                         return (ipddp_delete(&rcp));