NANC 124

Null Character Padding

Origination Date :07/17/1997

Originator:Perot

Description:

During MOC testing, two errors relating to null padded ASN values were discovered: with respect to the BER encoding of generalized time and graphic string.

Both of these base types use the Latin-1 (ISO 8859-1) character set which does not include the null character (Rec 208). Specifically, GeneralizedTime was encoded as a length of 23 with the first 17 bytes being the actual time value (YYYYMMDDHHMMSS.0Z) and the remaining 6 bytes being nulls.

Since GeneralizedTime shows up in almost every msg. pdu, this violation restricted the number of test cases that could be run. One other case was found relating to the encoding of the zipcode field in the AddressInfo ASN.1 type. This is declared as a graphic string of up to a size of 9 bytes. The first 6 bytes were actually populated by the zipcode value and the remaining 3 bytes were again null padded.

Final Resolution:

It will be documented in the IIS that “The exact lengths must be specified for ASN.1 data sent across the interface.  This will prevent trailing null characters that may not be accepted by some CMIP vendor products.”

Related Release:

1.5

Status: Implemented