decnet: Do not build routes to devices without decnet private data.

In particular, make sure we check for decnet private presence
for loopback devices.

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

1 files changed, 8 insertions, 1 deletions

diff --git a/net/decnet/dn_route.c b/net/decnet/dn_route.c
index 607a14f20d88..b1dc096d22f8 100644
--- a/net/decnet/dn_route.c
+++ b/net/decnet/dn_route.c
@@ -1034,10 +1034,13 @@ source_ok:
         if (!fld.daddr) {
                 fld.daddr = fld.saddr;
 
-                err = -EADDRNOTAVAIL;
                 if (dev_out)
                         dev_put(dev_out);
+                err = -EINVAL;
                 dev_out = init_net.loopback_dev;
+                if (!dev_out->dn_ptr)
+                        goto out;
+                err = -EADDRNOTAVAIL;
                 dev_hold(dev_out);
                 if (!fld.daddr) {
                         fld.daddr =
@@ -1110,6 +1113,8 @@ source_ok:
                 if (dev_out == NULL)
                         goto out;
                 dn_db = rcu_dereference_raw(dev_out->dn_ptr);
+                if (!dn_db)
+                        goto e_inval;
                 /* Possible improvement - check all devices for local addr */
                 if (dn_dev_islocal(dev_out, fld.daddr)) {
                         dev_put(dev_out);
@@ -1151,6 +1156,8 @@ select_source:
                         dev_put(dev_out);
                 dev_out = init_net.loopback_dev;
                 dev_hold(dev_out);
+                if (!dev_out->dn_ptr)
+                        goto e_inval;
                 fld.flowidn_oif = dev_out->ifindex;
                 if (res.fi)
                         dn_fib_info_put(res.fi);