Re: kern/44506: ieee80211_match_bss matches all different SSIDs of the identical length

[David Laight <david%l8s.co.uk@localhost>]

The following reply was made to PR kern/44506; it has been noted by GNATS.

From: David Laight <david%l8s.co.uk@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: kern/44506: ieee80211_match_bss matches all different SSIDs of the 
identical length
Date: Thu, 3 Feb 2011 08:15:52 +0000

 On Wed, Feb 02, 2011 at 11:25:01PM +0000, james.woo%rioch-usa.com@localhost 
wrote:
 > >Number:         44506
 > >Category:       kern
 > >Synopsis:       ieee80211_match_bss matches all different SSIDs of the 
 > >identical length
 ...
 >      ieee80211_match will match all different SSIDs of the identical length
 >      Connection is only successful if the target SSID has a higher RSSI than
 >      the other "matching" SSIDs. Otherwise, connection is not possible if 
 > the target SSID
 >      has a lower RSSI than the other "matching" SSIDs.
 > >How-To-Repeat:
 >      Assign different SSIDs of identical length to several APs.
 >      Try to connect to the one with the lowest RSSI. It will fail to connect.
 >      Now connect to the one with the highest RSSI. It will succeed.
 > >Fix:
 >      net80211/ieee80211_node.c, line 532-534 was
 >      if (ic->ic_dess_esslen != 0 &&
 >          (ni->ni_esslen != ic->ic_des_esslen ||
 >           memcmp(ni->ni_essid, ic->ic_des_essid, ic->ic_des_esslen) != 0))
 >      should be change to:
 >      if (ic->ic_des_esslen != 0) {
 >          if (ni->ni_esslen == ic->ic_des_esslen) {
 >              if (memcmp(ni->ni_essid, ic->ic_des_essid, ic->ic_dess_esslen) 
 > != 0)
 
 That change doesn't look right to me.
 The line following the confition is:   fail |= 0x19;
 So the old code sets fail if the length or contents of the ssid don't match.
 Your version won't set 'fail' if the lengths differ - but that isn't a match.
 
        David
 
 -- 
 David Laight: david%l8s.co.uk@localhost