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From: David Miller <>
Subject: Re: [PATCH] mac80211: Do not send Layer 2 Update frame before authorization
Date: Wed, 11 Sep 2019 15:59:55 +0200 (CEST)
Message-ID: <> (raw)
In-Reply-To: <>

From: Johannes Berg <>
Date: Wed, 11 Sep 2019 15:06:03 +0200

> On Wed, 2019-09-11 at 16:03 +0300, Jouni Malinen wrote:
>> The Layer 2 Update frame is used to update bridges when a station roams
>> to another AP even if that STA does not transmit any frames after the
>> reassociation. This behavior was described in IEEE Std 802.11F-2003 as
>> something that would happen based on MLME-ASSOCIATE.indication, i.e.,
>> before completing 4-way handshake. However, this IEEE trial-use
>> recommended practice document was published before RSN (IEEE Std
>> 802.11i-2004) and as such, did not consider RSN use cases. Furthermore,
>> IEEE Std 802.11F-2003 was withdrawn in 2006 and as such, has not been
>> maintained amd should not be used anymore.
>> Sending out the Layer 2 Update frame immediately after association is
>> fine for open networks (and also when using SAE, FT protocol, or FILS
>> authentication when the station is actually authenticated by the time
>> association completes). However, it is not appropriate for cases where
>> RSN is used with PSK or EAP authentication since the station is actually
>> fully authenticated only once the 4-way handshake completes after
>> authentication and attackers might be able to use the unauthenticated
>> triggering of Layer 2 Update frame transmission to disrupt bridge
>> behavior.
>> Fix this by postponing transmission of the Layer 2 Update frame from
>> station entry addition to the point when the station entry is marked
>> authorized. Similarly, send out the VLAN binding update only if the STA
>> entry has already been authorized.
> Reviewed-by: Johannes Berg <>
> Dave, if you were still planning to send a pull request to Linus before
> he closes the tree on Sunday this would be good to include (and we
> should also backport it to stable later).
> If not, I can pick it up afterwards, let me know.

Ok I applied this directly, thanks.

      reply index

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-09-11 13:03 Jouni Malinen
2019-09-11 13:06 ` Johannes Berg
2019-09-11 13:59   ` David Miller [this message]

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