eap Mailing List: Re: NULL character in EAP Identity Request/Response

[Bernard Aboba (aboba]

Here's what RFC 2284 says in Section 3.1:

      This field MAY contain a displayable message in the Request.  The
      Response uses this field to return the Identity.  If the Identity
      is unknown, this field should be zero bytes in length.  The field
      MUST NOT be null terminated.  The length of this field is derived
      from the Length field of the Request/Response packet and hence a
      null is not required.

Here's what RFC 2284bis-09 says in Section 5.1:

      This field MAY contain a displayable message in the Request,
      containing UTF-8 encoded ISO 10646 characters [RFC2279].  Where
      the Request contains a null, only the portion of the field prior
      to the null is displayed.  If the Identity is unknown, the
      Identity Response field should be zero bytes in length.  The
      Identity Response field MUST NOT be null terminated.  In all
      cases, the length of the Type-Data field is derived from the
      Length field of the Request/Response packet.

The difference is that the MUST NOT be null terminated directive applies
only to the Response, not to the Request.  I believe you are correct in
that a NULL can be present in the EAP Response. The Appendix appears
incorrect on this issue.