Re: kernel-5.18.8 breaks cifs mounts

[Julian Sikorski <belegdol@gmail.com>]

Am 05.07.22 um 07:28 schrieb Shyam Prasad N:
> On Mon, Jul 4, 2022 at 10:03 PM Julian Sikorski <belegdol@gmail.com> wrote:
>>
>>
>>
>> Am 03.07.22 um 19:51 schrieb Stefan Metzmacher:
>>> Am 03.07.22 um 07:01 schrieb Steve French:
>>>> I lean toward thinking that this is a Samba bug (although I don't see
>>>> it on my local system - it works to samba for me, although I was
>>>> trying against a slightly different version, Samba 4.15.5-Ubuntu).
>>>>
>>>> Looking at the traces in more detail they look the same (failing vs.
>>>> working) other than the order of the negotiate context, which fails
>>>> with POSIX as the 3rd context, and netname as the 4th, but works with
>>>> the order reversed (although same contexts, and same overall length)
>>>> ie with POSIX context as the fourth one and netname context as the
>>>> third one.
>>>>
>>>> The failing server code in Samba is in
>>>> smbd_smb2_request_process_negprot but I don't see changes to it
>>>> recently around this error.
>>>>
>>>> Does this fail to anyone else's Samba version?
>>>>
>>>> This is probably a Samba server bug but ... seems odd since it doesn't
>>>> fail to Samba for me.
>>>>
>>>> Jeremy/Metze,
>>>> Does this look familiar?
>>>
>>> Maybe this one:
>>>
>>> https://git.samba.org/?p=samba.git;a=commitdiff;h=147dd9d58a429695a3b6c6e45c8b0eaafc67908a
>>>
>>>
>>> that went only into 4.15 and higher.
>>>
>>> metze
>>
>> Nice catch, I can confirm that adding this patch to debian samba
>> 2:4.13.13+dfsg-1~deb11u3 package makes the mounts work again. How do we
>> get this patch into debian?
>>
>> Best regards,
>> Julian
> 
> Hi Metze,
> I went through the above patch, and it looks like an issue with
> parsing garbage at the end of the buffer, rather than negotiate count.
> I'm not sure how the netname negotiate context patches above are being
> affected by this samba server patch. The only difference from the
> client side for single channel is that the netname context appears as
> the 4th element in the list of 4, rather than the 3rd element in the
> list of 4. Do you have a possible explanation?
> 
> Julian,
> Thanks for the repro attempt. So I assume that with the latest samba
> server, things work as expected without reverting any changes in
> 5.18.8 kernel, correct?
> 
I have no way of testing a newer samba server unfortunately, but several 
people in this email discussion have mentioned that newer servers work 
for them:
- Paulo with W22
- Enzo and Steve with 4.15
- Steve with 4.16 without 
https://git.samba.org/?p=samba.git;a=commitdiff;h=147dd9d58a429695a3b6c6e45c8b0eaafc67908a

Best regards,
Julian