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 IEEE Std 802.11F-2003 was withdrawn in 2006 and as such, has not been 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 <johannes@xxxxxxxxxxxxxxxx> 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. Thanks, johannes
