188.8.131.52.5 Verifying the Credit Charge and the Payload Size
If Connection.SupportsMultiCredit is TRUE, the server MUST verify the CreditCharge field in the SMB2 header and the payload size (the size of the data within the variable-length field) of the request or the maximum response size.
If CreditCharge is zero and the payload size of the request or the maximum response size is greater than 64 kilobytes, the server MUST fail the request with the error code STATUS_INVALID_PARAMETER.
If CreditCharge is greater than zero, the server MUST calculate the expected CreditCharge for the current operation using the formula specified in section 184.108.40.206. If the calculated credit number is greater than the CreditCharge, the server MUST fail the request with the error code STATUS_INVALID_PARAMETER.