ip6_tunnel: better validate user provided tunnel names

Use valid_name() to make sure user does not provide illegal
device name.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 7 insertions, 4 deletions

diff --git a/net/ipv6/ip6_tunnel.c b/net/ipv6/ip6_tunnel.c
index df4c29f7d59f..da66aaac51ce 100644
--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -297,13 +297,16 @@ static struct ip6_tnl *ip6_tnl_create(struct net *net, struct __ip6_tnl_parm *p)
         struct net_device *dev;
         struct ip6_tnl *t;
         char name[IFNAMSIZ];
-        int err = -ENOMEM;
+        int err = -E2BIG;
 
-        if (p->name[0])
+        if (p->name[0]) {
+                if (!dev_valid_name(p->name))
+                        goto failed;
                 strlcpy(name, p->name, IFNAMSIZ);
-        else
+        } else {
                 sprintf(name, "ip6tnl%%d");
-
+        }
+        err = -ENOMEM;
         dev = alloc_netdev(sizeof(*t), name, NET_NAME_UNKNOWN,
                            ip6_tnl_dev_setup);
         if (!dev)