[Patches] s3:smbd: unimplement FSCTL_VALIDATE_NEGOTIATE_INFO with "server max protocol = SMB2_02" (bug #12772)

Stefan Metzmacher metze at samba.org
Sun Jul 2 21:35:54 UTC 2017


Hi Tom,

>> Now you could say it's stupid to run a server that has SMB3 implemented
>> using "server max protocol = SMB2_02". In theory I'd agree, but the
>> problem is that there is a bug in Windows (I think 2012 and 2012R2),
>> that a immediate reconnect to a server doesn't work if the negotiated
>> dialect jumps from SMB 2 to SMB 3. The client somehow gets the session
>> key for the SMB3 signing wrong. If you use "net use /del" wait something
>> like 30 seconds and reconnect it works fine using SMB3.
>> This is fixed in the Windows 10 client, but it's a problem for users of
>> older Versions.
> 
> Yes, it's unfortunate but a fairly high bar is required to justify patches to
> downlevel systems. By the way, if you disagree with any such decision, it's
> possible to discuss it further and potentially change.

I'd actually think fixing this in Windows 2012 and Windows 2012R2 (and
the relates client versions Windows 8 and 8.1) would be very helpful
in order to get new dialects enabled by more servers. If I remember
correctly I know about more than one vendor who didn't enable SMB3
by default because of this.

metze

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