mac80211: Breakage in software encryption (iwl3945)

mac80211: Breakage in software encryption (iwl3945)

[Maxim Levitsky]

I updated the kernel and lost connection to my WPA2
AP. Strangely the WPA handshake completes, but DHCP not.

I also unfortunately found that all that time I was using software
encryption (this is iwl3945 loaded with swcrypto=1).
Hardware encryption doesn't work ether and didn't work in the slightly
older kernel (but it did work once, I sure)

Now, the commit a6bae9e7ab19876a157c91019852395539e4f20e breaks software
encryption, with behaviour like described above.

Best regards,
Maxim Levitsky

Re: mac80211: Breakage in software encryption (iwl3945)

[Marcus Better]

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Maxim Levitsky wrote:
> I updated the kernel and lost connection to my WPA2
> AP. Strangely the WPA handshake completes, but DHCP not.

I have observed this a few times with 2.6.32.4. I could work around it by 
unloading and re-loading iwl3945.

> Now, the commit a6bae9e7ab19876a157c91019852395539e4f20e breaks software
> encryption, with behaviour like described above.

I don't think 2.6.32.4 includes that commit though.

Cheers,

Marcus
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Re: mac80211: Breakage in software encryption (iwl3945)

[Sedat Dilek]

Hi,

it is very helpful to give commit-id *and* commit-msg so that others
can follow more easily.
Which GIT repository (branch) is that?

Kind Regards,
- Sedat -

On Sat, Jan 23, 2010 at 9:10 PM, Maxim Levitsky <maximlevitsky@gmail.com> wrote:
> I updated the kernel and lost connection to my WPA2
> AP. Strangely the WPA handshake completes, but DHCP not.
>
> I also unfortunately found that all that time I was using software
> encryption (this is iwl3945 loaded with swcrypto=1).
> Hardware encryption doesn't work ether and didn't work in the slightly
> older kernel (but it did work once, I sure)
>
> Now, the commit a6bae9e7ab19876a157c91019852395539e4f20e breaks software
> encryption, with behaviour like described above.
>
> Best regards,
> Maxim Levitsky
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-wireless" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

Re: mac80211: Breakage in software encryption (iwl3945)

[Johannes Berg]

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Maxim,

Your mail is confusing me.

On Sat, 2010-01-23 at 22:10 +0200, Maxim Levitsky wrote:
> I updated the kernel and lost connection to my WPA2
> AP. Strangely the WPA handshake completes, but DHCP not.

What did you upgrade to?

> I also unfortunately found that all that time I was using software
> encryption (this is iwl3945 loaded with swcrypto=1).
> Hardware encryption doesn't work ether and didn't work in the slightly
> older kernel (but it did work once, I sure)

That must be a different problem, surely?

> Now, the commit a6bae9e7ab19876a157c91019852395539e4f20e breaks software
> encryption, with behaviour like described above.

And how did you arrive at that conclusion? Have you reverted the patch
and it works again? I really don't see how this particular patch could
break it since afaict it's entirely correct, there are exactly two tests
for IEEE80211_TX_INTFL_DONT_ENCRYPT in mac80211, both of which execute
before the code I removed.

johannes

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Re: mac80211: Breakage in software encryption (iwl3945)

[Marcus Better]

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Marcus Better wrote:
> Maxim Levitsky wrote:
>> I updated the kernel and lost connection to my WPA2
>> AP. Strangely the WPA handshake completes, but DHCP not.
> 
> I have observed this a few times with 2.6.32.4. I could work around it by
> unloading and re-loading iwl3945.

Oh, and I should say that I didn't see this with 2.6.31.6.

After the WPA handshake completed, I ran tcpdump and could see the outgoing 
DHCP requests, but no other traffic on the interface.

Cheers,

Marcus
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Re: mac80211: Breakage in software encryption (iwl3945)

[Maxim Levitsky]

On Sun, 2010-01-24 at 11:56 +0100, Johannes Berg wrote: 
> Maxim,
> 
> Your mail is confusing me.
> 
> On Sat, 2010-01-23 at 22:10 +0200, Maxim Levitsky wrote:
> > I updated the kernel and lost connection to my WPA2
> > AP. Strangely the WPA handshake completes, but DHCP not.
> 
> What did you upgrade to?
latest -git of wireless-testing

> 
> > I also unfortunately found that all that time I was using software
> > encryption (this is iwl3945 loaded with swcrypto=1).
> > Hardware encryption doesn't work ether and didn't work in the slightly
> > older kernel (but it did work once, I sure)
> 
> That must be a different problem, surely?
Sure, and I open a bugreport about it too.

> 
> > Now, the commit a6bae9e7ab19876a157c91019852395539e4f20e breaks software
> > encryption, with behaviour like described above.
> 
> And how did you arrive at that conclusion? Have you reverted the patch
> and it works again? I really don't see how this particular patch could
> break it since afaict it's entirely correct, there are exactly two tests
> for IEEE80211_TX_INTFL_DONT_ENCRYPT in mac80211, both of which execute
> before the code I removed.

I didn't want to add the standard meme: 'Commit X just before Y works,
commit Y doesn't. I reverted Y and now everything works fine.'

I bisected it, manually this time. Sorry for confusion.

I will continue that discussion in the thread about this patch.
(Also sorry for not including commit description....)


Best regards,
Maxim Levitsky

Re: mac80211: Breakage in software encryption (iwl3945)

[Jochen Friedrich]

Hi Maxim,

>> On Sat, 2010-01-23 at 22:10 +0200, Maxim Levitsky wrote:
>>> I updated the kernel and lost connection to my WPA2
>>> AP. Strangely the WPA handshake completes, but DHCP not.
>> What did you upgrade to?
> latest -git of wireless-testing

I have the same problem since compat-wireless-2010-01-20 with 
iwl3945. compat-wireless-2010-01-15 works OK. However, as i don't 
use any module parameters, i guess i'm using hw encryption.

Thanks,
Jochen

Re: mac80211: Breakage in software encryption (iwl3945)

[Jochen Friedrich]

Jochen Friedrich wrote:
> Hi Maxim,
> 
>>> On Sat, 2010-01-23 at 22:10 +0200, Maxim Levitsky wrote:
>>>> I updated the kernel and lost connection to my WPA2
>>>> AP. Strangely the WPA handshake completes, but DHCP not.
>>> What did you upgrade to?
>> latest -git of wireless-testing
> 
> I have the same problem since compat-wireless-2010-01-20 with 
> iwl3945. compat-wireless-2010-01-15 works OK. However, as i don't 
> use any module parameters, i guess i'm using hw encryption.

I bisected this to commit 813d76694043d00b59475baa1fbfaf54a2eb7fad. 
Reverting this patch makes compat-wireless-2010-01-20 and later run OK.

Thanks,
Jochen

Re: mac80211: Breakage in software encryption (iwl3945)

[Johannes Berg]

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On Mon, 2010-01-25 at 01:05 +0100, Jochen Friedrich wrote:

> > I have the same problem since compat-wireless-2010-01-20 with 
> > iwl3945. compat-wireless-2010-01-15 works OK. However, as i don't 
> > use any module parameters, i guess i'm using hw encryption.
> 
> I bisected this to commit 813d76694043d00b59475baa1fbfaf54a2eb7fad. 
> Reverting this patch makes compat-wireless-2010-01-20 and later run OK.

Thanks. I'll look into that today.

johannes

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Re: mac80211: Breakage in software encryption (iwl3945)

[Maxim Levitsky]

On Mon, 2010-01-25 at 00:27 +0100, Jochen Friedrich wrote: 
> Hi Maxim,
> 
> >> On Sat, 2010-01-23 at 22:10 +0200, Maxim Levitsky wrote:
> >>> I updated the kernel and lost connection to my WPA2
> >>> AP. Strangely the WPA handshake completes, but DHCP not.
> >> What did you upgrade to?
> > latest -git of wireless-testing
> 
> I have the same problem since compat-wireless-2010-01-20 with 
> iwl3945. compat-wireless-2010-01-15 works OK. However, as i don't 
> use any module parameters, i guess i'm using hw encryption.
Nether did I use any parameters. However software encryption is the
default today, this is why nobody notice it is broken.

I use WPA2 thus CCMP.


Best regards,
Maxim Levitsky