Hi Eric,
On Fri, Oct 21, 2016 at 7:28 PM, Eric Dumazet <eric.duma...@gmail.com> wrote:
> On Fri, 2016-10-21 at 19:02 +0800, f...@ikuai8.com wrote:
>> From: Gao Feng <f...@ikuai8.com>
>>
>> Current tun driver permits the ifr_flags is set with IFF_TUN and
>> IFF_TAP at the same time. But actually there is only IFF_TUN flag
>> works. And it does not make sense these two flags are set, so add
>> this check.
>>
>> Signed-off-by: Gao Feng <f...@ikuai8.com>
>> ---
>> v2: Remove useless {}
>> v1: Initial patch
>>
>> drivers/net/tun.c | 3 +++
>> 1 file changed, 3 insertions(+)
>>
>> diff --git a/drivers/net/tun.c b/drivers/net/tun.c
>> index 8093e39..faaa189 100644
>> --- a/drivers/net/tun.c
>> +++ b/drivers/net/tun.c
>> @@ -1752,6 +1752,9 @@ static int tun_set_iff(struct net *net, struct file
>> *file, struct ifreq *ifr)
>> if (err < 0)
>> return err;
>>
>> + if ((ifr->ifr_flags & (IFF_TUN | IFF_TAP)) == (IFF_TUN |
>> IFF_TAP))
>> + return -EINVAL;
>> +
>> /* Set dev type */
>> if (ifr->ifr_flags & IFF_TUN) {
>> /* TUN device */
>
>
> This might break some applications.
Yes. I consider about this case.
But I think there should be very least applications which set these
two flags at the same time.
>
> It might be too late to add this check without a grace period.
>
>
>
Yes, It needs some discussions.
Regards
Feng
