[Samba] client used more credits than granted?

[Michael Tokarev]

Hi!

More questions about the samba logging.  Currently seeing a lot of messages like this:


[2024/04/03 11:21:50.199540,  0, pid=3400491] source3/smbd/smb2_server.c:832(smb2_validate_message_id)
   smb2_validate_message_id: smb2_validate_message_id: client used more credits than granted, mid 2, charge 1, credits_granted 0, seqnum low/range: 1/0
[2024/04/03 11:45:45.220696,  0, pid=3403167] source3/smbd/smb2_server.c:832(smb2_validate_message_id)
   smb2_validate_message_id: smb2_validate_message_id: client used more credits than granted, mid 1, charge 1, credits_granted 0, seqnum low/range: 1/0

(most of them are 2nd kind, *some* are 1st (with "mid 2") kind).

The client is Windows 2012R2 server.

What does this message mean?

I see in the source that smb2_validate_message_id (which is repeated twice in
the message text, btw) return false in this case, so smbd_smb2_request_validate()
return NT_STATUS_INVALID_PARAMETER.

But what all this *means* in practice?  What the client will/should do?
Why this is logged and why it is an error?

Thanks,

/mjt