ipv4: fix wildcard search with inet_confirm_addr()

Help of this function says: "in_dev: only on this interface, 0=any interface",
but since commit 39a6d0630012 ("[NETNS]: Process inet_confirm_addr in the
correct namespace."), the code supposes that it will never be NULL. This
function is never called with in_dev == NULL, but it's exported and may be used
by an external module.

Because this patch restore the ability to call inet_confirm_addr() with in_dev
== NULL, I partially revert the above commit, as suggested by Julian.

CC: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Reviewed-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 5 deletions

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 6f49efc9d4b7..84956f5f0135 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -1240,22 +1240,21 @@ static __be32 confirm_addr_indev(struct in_device *in_dev, __be32 dst,
 
 /*
  * Confirm that local IP address exists using wildcards:
- * - in_dev: only on this interface, 0=any interface
+ * - net: netns to check, cannot be NULL
+ * - in_dev: only on this interface, NULL=any interface
  * - dst: only in the same subnet as dst, 0=any dst
  * - local: address, 0=autoselect the local address
  * - scope: maximum allowed scope value for the local address
  */
-__be32 inet_confirm_addr(struct in_device *in_dev,
+__be32 inet_confirm_addr(struct net *net, struct in_device *in_dev,
 			 __be32 dst, __be32 local, int scope)
 {
 	__be32 addr = 0;
 	struct net_device *dev;
-	struct net *net;
 
-	if (scope != RT_SCOPE_LINK)
+	if (in_dev != NULL)
 		return confirm_addr_indev(in_dev, dst, local, scope);
 
-	net = dev_net(in_dev->dev);
 	rcu_read_lock();
 	for_each_netdev_rcu(net, dev) {
 		in_dev = __in_dev_get_rcu(dev);