[PATCH mac80211] cfg80211: fix channel configuration in IBSS join

[Arend van Spriel]

On 01/28/2014 10:54 AM, Antonio Quartulli wrote:
> With the current approach if another cell having the same
> BSSID (but using a different channel) exists then cfg80211
> picks up the wrong BSS object.

Not entirely sure this patch is right. How can you have another IBSS
cell with the same BSSID. That sounds dead wrong to me. Here is what
IEEE802.11-2012 has to say about the BSSID:

"If the BSSType indicates an IBSS, the STA shall start an IBSS, and the
BSSID shall be an individual locally administered IEEE MAC address as
defined in 9.2 of IEEE Std 802-2001. The remaining 46 bits of that MAC
address shall be a number selected in a manner that minimizes the
probability of STAs generating the same number, even when those STAs are
subjected to the same initial conditions.""

> The result is a mismatching channel configuration between
> cfg80211 and the driver, that can lead to any sort of
> problem.
> 
> The issue can be triggered by having an IBSS sitting on
> given channel and then asking the driver to create a new
> cell using the same BSSID but with a different frequency.

So you have a single driver/device in which you setup two IBSS cells and
it allows you/user-space to use the same BSSID. That is strange.