WEP fails with Unsupported authentication algorithm (7820)

[Yegor Yefremov]

Hi Sergey,

On Mon, Aug 10, 2020 at 4:28 PM Sergey Matyukevich <geomatsi at gmail.com> wrote:
>
> Hi Egor,
>
> > > > During the transition from wpa_supplicant v2.4 to v2.9 on a legacy
> > > > project I get the following message:
> > > >
> > > > mgmt::auth
> > > > authentication: STA=7c:dd:90:44:a5:83 auth_alg=7820
> > > > auth_transaction=112 status_code=31962 wep=1 seq_ctrl=0x60a0
> > > > Unsupported authentication algorithm (7820)
> > > > authentication reply: STA=7c:dd:90:44:a5:83 auth_alg=7820
> > > > auth_transaction=113 resp=13 (IE len=0) (dbg=handle-auth)
> > > >
> > > > My conf file looks like this:
> > > >
> > > > ctrl_interface=/var/run/wpa_supplicant
> > > > ap_scan=1
> > > >
> > > > network={
> > > >         ssid="myssid"
> > > >         mode=2
> > > >         frequency=2447
> > > >         key_mgmt=NONE
> > > >         wep_key0="passw"
> > > >         wep_tx_keyidx=0
> > > > }
> > > >
>
> ...
>
> > The old working rootfs had wpa_supplicant 2.4 but I have also tested
> > it with the same kernel version 5.4.8. wpa_supplicant 2.10 has no
> > problem with WPA/WPA2 and no encryption. The only problem so far is
> > WEP.
>
> Coud you please clarify which combination of kernel/wpa_ did work on
> your setup ? Did your WEP setup worked with new kernel and old wpa_s ?

Buildroot 2016: Linux 3.18.x: wpa_supplicant 2.4: OK
Buildroot 2016: Linux 5.4.x: wpa_supplicant 2.4: OK
Buildroot 2020: Linux 5.4.x: wpa_supplicant 2.6 - 2.10: KO

> I could not reproduce similar behavior using hwsim and AP and STA both
> operated by wpa_s. What kind of client are you using ? Is it possible
> to configure auth_alg on your client ?

My client is Ubuntu 18.04.3 LTS with 2.6.

> If you can configure auth_alg on both AP and STA, then could you please
> try explicitly specify the same auth_alg on both sides. For this purpose
> you may set auth_alg=OPEN or auth_alg=SHARED in wpa_supplicant configs
> for both AP and STA network configurations. If client configuration is
> beyond your control, then could you please try explictly both auth_alg
> options on AP side.

Both sides auth_alg=SHARED - KO but both sides OPEN - OK.

Regards,
Yegor
> Regargs,
> Sergey