Le 30 nov. 2018 à 15:31, Sabrina Dubroca <s...@queasysnail.net> a écrit :
> 2018-11-27, 14:05:42 +0100, Alexis Bauvin wrote:
>> diff --git a/net/ipv4/udp_tunnel.c b/net/ipv4/udp_tunnel.c
>> index 6539ff15e9a3..dc68e15a4f72 100644
>> --- a/net/ipv4/udp_tunnel.c
>> +++ b/net/ipv4/udp_tunnel.c
>> @@ -20,6 +20,16 @@ int udp_sock_create4(struct net *net, struct udp_port_cfg
>> *cfg,
>> if (err < 0)
>> goto error;
>>
>> + if (cfg->bind_ifindex) {
>> + struct net_device *dev;
>> +
>> + dev = __dev_get_by_index(net, cfg->bind_ifindex);
>
> Quoting from net/core/dev.c:
>
> * [...] The device has not
> * had its reference counter increased so the caller must be careful
> * about locking. The caller must hold either the RTNL semaphore
> * or @dev_base_lock.
> */
>
> which is the case for VXLAN (and GENEVE) during ndo_open, but I don't
> think other UDP tunnels (FOU, L2TP) are holding RTNL when they call
> udp_sock_create(). dev_get_by_index() + dev_put() should be safe.
>
> Also, I don't think it's a problem with vxlan, but this could handle
> the case where __dev_get_by_index returns NULL.
First, sorry for the (late) response, thanks for the feedback!
That’s a real issue I did not take into account when writing the patch; still
too new to kernel dev.
Fixing and spinning up v7.
>> + err = kernel_setsockopt(sock, SOL_SOCKET, SO_BINDTODEVICE,
>> + dev->name, strlen(dev->name) + 1);
>> + if (err < 0)
>> + goto error;
>> + }
>> +
>> udp_addr.sin_family = AF_INET;
>> udp_addr.sin_addr = cfg->local_ip;
>> udp_addr.sin_port = cfg->local_udp_port;
>
> --
> Sabrina
