Apple has a bug in credit handling with their smbfs, it seems :-)

[Stefan Metzmacher]

Am 23.01.19 um 21:34 schrieb Jeremy Allison:
> On Wed, Jan 23, 2019 at 09:16:31PM +0100, Stefan Metzmacher wrote:
>> Am 23.01.19 um 20:44 schrieb Jeremy Allison via samba-technical:
>>> On Mon, Jan 21, 2019 at 07:22:48PM -0800, Richard Sharpe via samba-technical wrote:
>>>> Hi folks,
>>>>
>>>> Apple has a bug in their handling of credits when Samba returns
>>>> STATUS_PENDING for a SESSION SETUP request.
>>>>
>>>> Such responses only seem to occur when the Samba server is under heavy load.
>>>>
>>>> Samba issues one credit in such cases, and, as per the spec issues
>>>> zero credits in the final successful response to the SESSION SETUP.
>>>>
>>>> The Mac then issues a TREE CREATE, consuming one credit and getting one credit.
>>>>
>>>> The Mac then issues a compound CREATE and CLOSE. This is a protocol
>>>> violation and Samba drops the connection.
>>>>
>>>> I have communicated this issue to Apple, but I also created the
>>>> attached patch to mitigate the issue while Apple thinks about fixing
>>>> their code.
>>>>
>>>> Is it worth doing this? Is it going to work?
>>>
>>> So this is sending credits on the SESSION SETUP
>>> interim reply, and then also on the final SESSION SETUP
>>> reply, yeah ?
>>>
>>> Have you tested this against the Apple client ?
>>>
>>> It's really ugly and a protocol violation :-).
>>>
>>> How often does this problem occur ? If it did
>>> go in it'd have to be configured off by default
>>> but I'm not convinced yet :-).
>>
>> I'd propose to skip the STATUS_PENDING using
>> smb2_request_set_async_internal() and leave the credit handling as is.
> 
> Trouble with that is the client may then timeout.

I think that's what windows also does that, but we should retest that
with a Samba dc and sleep(60) in SamLogon*.

metze


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