8.2.1 WPA testing
javier at cozybit.com
Mon Mar 2 13:39:10 EST 2009
On Sun, Mar 1, 2009 at 4:08 PM, Chris Ball <cjb at laptop.org> wrote:
> I've been working on trying to quantify the difference in WPA behavior
> between 8.2.0 and 8.2.1.
> Failures leave the string "Activation (eth0/wireless): disconnected
> during association, asking for new key" in /var/log/messages. A second
> type of failure is seen only on 8.2.0, namely "Unhandled network
> capabilities 10000001"; this bug is fixed in 8.2.1, and was not included
> in the totals below.
There were a number of timing problems between the driver,
wpa_supplicant and NM, and the "Unhandled network..." was one of them.
See #8667 and #8799 for more details. The patches submitted for
those tickets addressed some of the problems, but not all.
In addition to this, there are two important wireless fixes in 8.2.1:
#7825 and #9048. The first one is a failure to associate to "fast"
Access Points when WPA is enabled. This was a serious problem, making
it impossible (not just unreliable) to associate with certain AP
models. The second problem was causing a packet loss while scanning,
something the xo does quite frequently.
> For this particular bug (being asked to re-enter the WPA passphrase
> at connection time), with the particular WPA access points at 1cc, we
> already had sporadic failures as of 8.2.0. 8.2.1 appears to make them
> slightly worse, perhaps suggesting a widening of a race condition in
> the newer driver or wireless firmware. We already know installing
> WPA keys to be time-critical: see relevant recent commits ¹ and ².
I would suggest to compare the two versions with different AP models.
For instance, with the D-Link WBR-2310 you will see a huge improvement
when using 8.2.1.
> We should not claim reliable WPA support in 8.2.1.
Agreed. However, I believe you can claim reliable WPA2 support, as
the WPA2 handshake doesn't have this timing vulnerability.
Have not tested extensively, but my experience was that WPA2 was very reliable.
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