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Fix dereference of skb pointer after free.

ROSE Ralf Baechle DL5RB 1 participant 2 messages May 13, 2006 – May 14, 2006 Networking

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Ralf Baechle DL5RB

author
#0 lore raw

If rose_route_frame return success we'll dereference a stale pointer. Likely this is only going to result in bad statistics for the ROSE interface.

Testers requested.

Signed-off-by Ralf Baechle <[email protected]>
---
 net/rose/rose_dev.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
net/rose/rose_dev.c +4 -1
Index: linux-net/net/rose/rose_dev.c
===================================================================
@@ -60,6 +60,7 @@ static int rose_rebuild_header(struct sk
 	struct net_device_stats *stats = netdev_priv(dev);
 	unsigned char *bp = (unsigned char *)skb->data;
 	struct sk_buff *skbn;
+	unsigned int len;
 
 #ifdef CONFIG_INET
 	if (arp_find(bp + 7, skb)) {

@@ -76,6 +77,8 @@ static int rose_rebuild_header(struct sk
 
 	kfree_skb(skb);
 
+	len = skbn->len;
+
 	if (!rose_route_frame(skbn, NULL)) {
 		kfree_skb(skbn);
 		stats->tx_errors++;

@@ -83,7 +86,7 @@ static int rose_rebuild_header(struct sk
 	}
 
 	stats->tx_packets++;
-	stats->tx_bytes += skbn->len;
+	stats->tx_bytes += len;
 #endif
 	return 1;
 }
author
#1 lore raw

Please don't use the previous patch; it's broken. Here's the right one.

Ralf

[NETROM] Fix possible null pointer dereference.

If in nr_link_failed the neighbour list is non-empty but the node list is empty we'll end dereferencing a in a NULL pointer.

This fixes coverity 362.

Signed-off-by Ralf Baechle <[email protected]>
 net/netrom/nr_route.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)
net/netrom/nr_route.c +8 -4
Index: linux-net/net/netrom/nr_route.c
===================================================================
@@ -725,15 +725,17 @@ void nr_link_failed(ax25_cb *ax25, int r
 	struct nr_node  *nr_node = NULL;
 
 	spin_lock_bh(&nr_neigh_list_lock);
-	nr_neigh_for_each(s, node, &nr_neigh_list)
+	nr_neigh_for_each(s, node, &nr_neigh_list) {
 		if (s->ax25 == ax25) {
 			nr_neigh_hold(s);
 			nr_neigh = s;
 			break;
 		}
+	}
 	spin_unlock_bh(&nr_neigh_list_lock);
 
-	if (nr_neigh == NULL) return;
+	if (nr_neigh == NULL)
+		return;
 
 	nr_neigh->ax25 = NULL;
 	ax25_cb_put(ax25);

@@ -743,11 +745,13 @@ void nr_link_failed(ax25_cb *ax25, int r
 		return;
 	}
 	spin_lock_bh(&nr_node_list_lock);
-	nr_node_for_each(nr_node, node, &nr_node_list)
+	nr_node_for_each(nr_node, node, &nr_node_list) {
 		nr_node_lock(nr_node);
-		if (nr_node->which < nr_node->count && nr_node->routes[nr_node->which].neighbour == nr_neigh)
+		if (nr_node->which < nr_node->count &&
+		    nr_node->routes[nr_node->which].neighbour == nr_neigh)
 			nr_node->which++;
 		nr_node_unlock(nr_node);
+	}
 	spin_unlock_bh(&nr_node_list_lock);
 	nr_neigh_put(nr_neigh);
 }