[PATCH 4.14 121/138] ip6_tunnel: better validate user provided tunnel names

From: Greg Kroah-Hartman
Date: Tue Apr 10 2018 - 18:39:14 EST


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

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

From: Eric Dumazet <edumazet@xxxxxxxxxx>


[ Upstream commit db7a65e3ab78e5b1c4b17c0870ebee35a4ee3257 ]

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@xxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/ipv6/ip6_tunnel.c | 11 +++++++----
1 file changed, 7 insertions(+), 4 deletions(-)

--- a/net/ipv6/ip6_tunnel.c
+++ b/net/ipv6/ip6_tunnel.c
@@ -297,13 +297,16 @@ static struct ip6_tnl *ip6_tnl_create(st
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)