[PATCH][netifd] system-linux: initialize ifreq struct before using it

[Alin Năstac]

Hi Hans,

The issue I have involved adding an external device to the lan bridge
through add_device ubus call. Sometimes this operation fails to add
the new bridge port with the following device debug traces:
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]:
device_create_default(525): Create simple device 'wds1_1_2'
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]:
device_init_virtual(478): Initialize device 'wds1_1_2'
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]:
device_set_present(634): Network device 'wds1_1_2' is now present
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]:
__device_add_user(710): Add user for device 'wds1_1_2', refcount=1
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]: device_claim(413):
Claim Network device wds1_1_2, new active count: 1
Wed Oct  7 04:22:57 2020 daemon.err netifd[2843]: device_claim(432):
claim Network device wds1_1_2 failed: -1

I'm not sure it fixes the problem I experience (the jury is still out
on that), but it is definitely caused by system_if_resolve() failure
to retrieve the interface index. Looking at the handling of
SIOCGIFINDEX in the kernel, it shouldn't matter if the rest of the
fields are uninitialized, but a variable should always be initialized
before its first use.

BR,
Alin

On Thu, Oct 8, 2020 at 2:15 PM Hans Dedecker <dedeckeh at gmail.com> wrote:
>
> Hi Alin,
>
> On Thu, Oct 8, 2020 at 1:31 PM Alin Nastac <alin.nastac at gmail.com> wrote:
> Could you add which issue this fixes ?
>
> Thx
> Hans
> >
> > Signed-off-by: Alin Nastac <alin.nastac at gmail.com>
> > ---
> >  system-linux.c | 2 ++
> >  1 file changed, 2 insertions(+)
> >
> > diff --git a/system-linux.c b/system-linux.c
> > index 6778b1d..9188899 100644
> > --- a/system-linux.c
> > +++ b/system-linux.c
> > @@ -904,6 +904,8 @@ failure:
> >  int system_if_resolve(struct device *dev)
> >  {
> >         struct ifreq ifr;
> > +
> > +       memset(&ifr, 0, sizeof(ifr));
> >         strncpy(ifr.ifr_name, dev->ifname, sizeof(ifr.ifr_name) - 1);
> >         if (!ioctl(sock_ioctl, SIOCGIFINDEX, &ifr))
> >                 return ifr.ifr_ifindex;
> > --
> > 2.7.4
> >