fix core dump when using physical interface

If the physical link is not specified in the configuration
the check in if_nametoindex(netdev->link) leads to a segfault.

Check the link is specified.

Signed-off-by: Daniel Lezcano <dlezcano@fr.ibm.com>
Reported-by: Ferenc Wagner <wferi@niif.hu>

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index a118ae197cc75ef6b6a87f79adc8eaab4dd588f8..8cc1a8f5ca4c88013c2978e777504393d82e3266 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1285,6 +1285,11 @@ static int instanciate_vlan(struct lxc_netdev *netdev)
 
 static int instanciate_phys(struct lxc_netdev *netdev)
 {
+       if (!netdev->link) {
+               ERROR("no link specified for the physical interface");
+               return -1;
+       }
+
        netdev->ifindex = if_nametoindex(netdev->link);
        if (!netdev->ifindex) {
                ERROR("failed to retrieve the index for %s", netdev->link);