[PATCH 4.5 002/101] decnet: Do not build routes to devices without decnet private data.

[Greg Kroah-Hartman]

4.5-stable review patch.  If anyone has any objections, please let me know.

------------------

From: "David S. Miller" <da...@davemloft.net>

[ Upstream commit a36a0d4008488fa545c74445d69eaf56377d5d4e ]

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

Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
 net/decnet/dn_route.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- 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);