[ovs-dev] [PATCH] Prevent kernel warning length of ovs attribute.

[Nathanael Davison]

Thanks for getting back to me, I'll look into getting it into the 
upstream kernel.

Nathanael

On 22/02/2019 23:50, Ben Pfaff wrote:
> On Wed, Dec 12, 2018 at 03:06:43PM +0000, Nathanael Davison wrote:
>> Linux kernel commit 6e237d099fac introduced warnings when validating the
>> length of some types. This exposed a bug in dpif-netlink.c
>> dpif_netlink_vport_to_ofpbuf where ovs was passing the upcall pids as
>> variable length array while the kernel was expecting a single u32. This
>> resulted in the kernel reporting "netlink: 'ovs-vswitchd': attribute
>> type 5 has an invalid length.".
>>
>> This patch changes the kernel to expect NLA_UNSPEC, which is for
>> arbitrary length data.
>>
>> Signed-off-by: Nathanael Davison <nathanael.davison at citrix.com>
>> ---
>>   datapath/datapath.c | 2 +-
>>   1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/datapath/datapath.c b/datapath/datapath.c
>> index e3d3c8c..3204bf3 100644
>> --- a/datapath/datapath.c
>> +++ b/datapath/datapath.c
>> @@ -2170,7 +2170,7 @@ static const struct nla_policy vport_policy[OVS_VPORT_ATTR_MAX + 1] = {
>>   	[OVS_VPORT_ATTR_STATS] = { .len = sizeof(struct ovs_vport_stats) },
>>   	[OVS_VPORT_ATTR_PORT_NO] = { .type = NLA_U32 },
>>   	[OVS_VPORT_ATTR_TYPE] = { .type = NLA_U32 },
>> -	[OVS_VPORT_ATTR_UPCALL_PID] = { .type = NLA_U32 },
>> +	[OVS_VPORT_ATTR_UPCALL_PID] = { .type = NLA_UNSPEC },
>>   	[OVS_VPORT_ATTR_OPTIONS] = { .type = NLA_NESTED },
>>   };
> This seems like it fell through the cracks.  Sorry about that.
>
> Nathanael, the usual way to get fixes into the OVS datapath directory is
> to first get them into the upstream kernel "net-next".  It doesn't look
> like this is there yet, so it's not yet time to submit it to ovs-dev.
> Instead, you should start with the Linux netdev mailing list (but you'll
> need to modify the patch to apply to net/openvswitch/datapath.c in that
> tree instead).
>
> Greg (CCed) might be able to help, if you need it.
>
> Thanks,
>
> Ben.