Re: [PATCH] mac80211: keep non-zero sequence counter of injected frames

[Mathy Vanhoef <Mathy.Vanhoef@kuleuven.be>]

The kernel test robot highlighted a bug in the patch. So for now do not
apply this one.

I'm currently testing the injection behavior of some new devices I
have, since my current ones are getting old, and I'll send updated
patches within a week or two if all goes well.

On Sun, 28 Jun 2020 20:59:56 +0200
Johannes Berg <johannes@sipsolutions.net> wrote:

> On Sun, 2020-06-28 at 22:05 +0400, Mathy Vanhoef wrote:
> > The sequence number of injected frames is being overwritten by the
> > function ieee80211_tx_h_sequence when the following two conditions
> > are met:
> > 
> > 1. The frame is injected on a virtual interface, and a second
> > virtual interface on this device is operating in managed/AP/.. mode.
> > 
> > 2. The sender MAC address of the injected frame matches the MAC
> >    address of the second interface operating in managed/AP/.. mode.
> > 
> > In some cases this may be desired, for instance when hostap is
> > configured to send certain frames using a monitor interface, in
> > which case the user-space will not assign a sequence number and
> > instead injects frames with a sequence number of zero.  
> 
> Yeah, this is where that used to be used. I'm thinking we should
> "break" this stuff eventually, tell people to use modern hostapd
> versions, and see who cares ... because all this "cooked monitor"
> etc. is all quite ugly.
> 
> > However, in case the user-space does assign a non-zero sequence
> > number, this number should not be overwritten by the kernel. This
> > patch adds a check to see if injected frames have already been
> > assigned a non-zero sequence number, and if so, this sequence
> > number will not be overwritten by the kernel.  
> 
> Seems reasonable, but I have to wonder what you're up to now ;-)
> 
> Anyway, I'll apply this unless I find some tests fail or something,
> but I'll be going on vacation soon, so it'll be a while (since it's
> for the -next tree as a feature).
> 
> johannes
>