WEP fails with Unsupported authentication algorithm (7820)

[Yegor Yefremov]

Hi Sergey,

On Sat, Aug 15, 2020 at 8:24 PM Sergey Matyukevich <geomatsi at gmail.com> wrote:
>
> > 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.
>
> Hi Egor,
>
> I could not reproduce anything similar to your issue using hwsim driver
> and different software versions: no corrupted AUTH frames for shared
> key authentication. In fact now I would guess that the issue is related
> to WiLink driver and/or its firmware.

You are right. I have performed the same tests against RaLink WLAN
Dongle and they were successful.

> By the way, shared key authentication does not make WEP stronger (rather
> the opposite). So if you have usecases for WEP, you can 'safely' switch
> to open authentication, until you figure out the root cause.

Thanks for debugging.

Regards,
Yegor