[kismac] Re: Solution to AE Passive Mode kernel panics, unable to load Monitor Mode

  • From: Robin L Darroch <robin@xxxxxxxxxxxxx>
  • To: kismac@xxxxxxxxxxxxx
  • Date: Tue, 2 May 2006 11:11:16 +0800

Fair suggestion that such a script could be added, and executed in the event that the user attempts to start a scan using Airport Extreme passive mode without persistent passive mode support enabled. I haven't played with shell script execution from KisMAC myself, so might need to leave that to someone else to add in... or I'll have a look if I get a chance.

Incidentally - I understand the conceptual argument for not enabling wlt1 (i.e. that your system kext list remains pure as the day it shipped from Apple), but is there a practical reason not to do so?

Robin:

I think the warning is a good idea, but I would urge you to reconsider my previous suggestions. Here's why:

If KisMac executed the commands when loading AE MM, then at the very least it sends a HUP signal to SystemUIServer. But at best, it prevents a kernel panic from happening with _standard hardware_ under _standard conditions_. In my opinion, it's a win-win situation!

I agree that it would be difficult to be grepping the process list for dozens of problematic daemons, but when it's just two, and they are practically guaranteed to be there - ready to cause a kernel panic - then why not? We're trusting KisMac with root permissions - I think it would be fair to expect it does all it can to not crash our systems (but it is alpha, so we forgive you, KisMac, because we love you).

Mac OS X is an awesome operating system, one where we can load Extensions on the fly - where we don't have to reboot. That was the kind of stuff we dreamt about back in the classic days... at least there was the programmer's key for when things bombed...

Anyways, just another person's $0.02.
- Rick

On May 1, 2006, at 12:00 AM, Robin L Darroch wrote:

Just my $.02: I completely disagree. I think that's assuming way too much. I don't even _use_ my built-in AE adapter with Kismac -- I use a Prism-based PCCard for scanning/capture. From my vantage point, I'd be quite annoyed if an application even touched a wireless adapter I don't even let it use.

The most I'd be willing to compromise on this is to have it prompt to enable that setting the first time it's run against an AE adapter (this whole installer, reboot after installation thing is very Windows-like -- Kismac works just fine being copied from a .dmg to /Applications, or wherever you desire). Let's not lose sight of the fact that this is a Mac application; no unnecessary installers mucking about with things that don't (or shouldn't) belong to them! ;-)

Fair call.

On reflection, you're absolutely right: the installer is no place for tweaking system default settings, and there is no reason for it to mess with Airport Extreme if you choose never to use it. I apologise for the suggestion, except that I think it's highlighted what we *should* do instead - see below. :)

The program advertises Airport Extreme passive mode support, so it should support it with the least possible chance of Windowsesque behaviour (i.e. system crashes, hardware ceasing to function without a reboot, etc). To do that, it has to enable what we currently call "permanent" mode, because that's the cleanest way to do it. I think the name "permanent passive" is misleading, and suggest replacing it with "system-level passive support". Considering the input from various parties in response to my message this morning, I submit the following revised proposal to the list:

--- the proposal ---

1) the installer should continue to do NOTHING about enabling or otherwise Airport Extreme "permanent" passive mode support

2) when adding the Airport Extreme passive mode adapter in the drivers preference pane, KisMAC should check if system-level passive support already enabled
* if not:
- enables system-level passive support
- recommends STRONGLY (see below) that the user reboot prior to scanning
* else:
- no need to do anything - it will work


3) the check box at the bottom should be cleared by default, but re-labeled "disable system level passive mode support" - if the user ticks this box, a warning will come up indicating that they may cause problems including Kernel panics if they attempt to scan without first deactivating all processes using the Airport Extreme card.

4) when removing Airport Extreme passive mode adapter from the drivers list, I would suggest doing nothing (frequently they'll want to add it in at a later date, and we can save a reboot by doing nothing). However, we *could* prompt the user "Do you wish to disable system-level passive support at this time?", with a default of No.

--- end proposal ---

By the above combination of steps we:
- ensure that the simplest user experience is correct
- ensure that the program does not need an installer to run correctly
- still allow expert users to disable system-level support (which is really what "permanent" passive support is), but warns them what they'll be getting into


What does everyone think of that plan?

Cheers,
Robin
--

-------------------------------------------------------------------------
 Robin L. Darroch - PO Box 2715, South Hedland WA 6722 - +61 421 503 966
      robin@xxxxxxxxxxxxx - robin@xxxxxxxxxxx - robin@xxxxxxxxxxxxx


--

-------------------------------------------------------------------------
 Robin L. Darroch - PO Box 2715, South Hedland WA 6722 - +61 421 503 966
      robin@xxxxxxxxxxxxx - robin@xxxxxxxxxxx - robin@xxxxxxxxxxxxx


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