Re: [PATCH] mac80211: fix races between siwessid and siwencode

[Dan Williams <dcbw@redhat.com>]

On Thu, 2008-03-06 at 15:01 +0100, Helge Hafting wrote:
> Tomas Winkler wrote:
> > On Wed, Mar 5, 2008 at 3:53 PM, Helge Hafting
> > <helge.hafting@aitel.hist.no> wrote:
> >   
> >> Joonwoo Park wrote:
> >>  > On Wed, Mar 05, 2008 at 06:40:09PM +0900, Joonwoo Park wrote:
> >>  >
> >>  >> resolve: http://bughost.org/bugzilla/show_bug.cgi?id=1522
> >>  >>
> >>  >> The function ieee80211_ioctl_siwencode shouldn't be called if
> >>  >> authentication process is not completed.
> >>  >> This patch makes the ieee80211_ioctl_siwessid to wait for authentication
> >>  >> is completed.
> >>  >>
> >>  >> Signed-off-by: Joonwoo Park <joonwpark81@gmail.com>
> >>  >>
> >>  >
> >>  > Helge,
> >>  >
> >>  > Can you please try this patch?
> >>  > I believe this patch helps your problem.
> >>  >
> >>  I tried it, and still have problems. The messages may be slightly different:
> >>
> >>  I first bring up the interface with "ifconfig wlan0 up"
> >>  and then try "iwconfig wlan0 essid my_essid key s:password"
> >>  over and over till it works. This gave me:
> >>
> >>  Initial auth_alg=0
> >>  wlan0: authenticate with AP 00:14:1b:5e:13:40
> >>  wlan0: authenticate with AP 00:14:1b:5e:13:40
> >>  wlan0: authenticate with AP 00:14:1b:5e:13:40
> >>  wlan0: authentication with AP 00:14:1b:5e:13:40 timed out
> >>
> >>  A total of 5 tries went wrong. The sixth time it worked, with
> >>  different messages and a different access point.
> >>  (There are several access points at work.)
> >>  Initial auth_alg=0
> >>  wlan0: authenticate with AP 00:12:7f:ce:9c:e0
> >>  wlan0: RX authentication from 00:12:7f:ce:9c:e0 (alg=0 transaction=2
> >>  status=0)
> >>  wlan0: authenticated
> >>  wlan0: associate with AP 00:12:7f:ce:9c:e0 (capab=0x431 status=0 aid=242)
> >>  wlan0: associated
> >>  wlan0: CTS protection enabled (BSSID=00:12:7f:ce:9c:e0)
> >>  wlan0: switched to long barker preamble (BSSID=BSSID=00:12:7f:ce:9c:e0)
> >>  wlan0: WMM queue=2 aci=0 acm=0 aifs=3 cWmin=15 cWmax=1023 burst=0
> >>  wlan0: WMM queue=3 aci=1 acm=0 aifs=7 cWmin=15 cWmax=1023 burst=0
> >>  wlan0: WMM queue=1 aci=2 acm=0 aifs=2 cWmin=7 cWmax=15 burst=30
> >>  wlan0: WMM queue=0 aci=3 acm=0 aifs=2 cWmin=3 cWmax=7 burst=15
> >>  wlan0: link becomes ready
> >>
> >>
> >>  Only 6 attempts is an improvement, if it stays that way.  Still, the
> >>  old ipw3945 succeeded on first try. :-/
> >>  I hope the testing can be of help.
> >>
> >>  Helge Hafting
> >>
> >>
> >>
> >>     
> > Is this shared or open authentication?
> > Do you happend to have a sniff capture of the association ?
> I am not sure what you mean by the question.
> This network uses WEP encryption (some users have older wireless equipment)
> there is one essid and a single shared password that everybody uses.
> Security is not that important, this is mostly to keep out outside bandwith
> wasters/pirates.

WEP has two authentication modes, "Shared Key" and "Open System".  He
wants to know which method your access point is using.  During
authentication, Open System is a simple two-frame request/response.  For
Shared Key, there's an additional challenge/response where the AP sends
a block of data, the client encrypts it with the WEP key, and sends it
back to the AP where it's verified.  Only if it verifies does the AP
complete association with the client.

You need to ensure that the mode matches between clients and the AP.
Some APs have an "Auto" option that just accepts both methods from the
client.

Dan

> I do not have a sniff of this association, but I can try to sniff the 
> next time.
> will wireshark be useful, or is some kind of wireless specific sniffer 
> needed?
> 
> 
> Helge Hafting
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