[bug-inetutils] Three bugs of Inetd: fix_tcpmux().

[Mats Erik Andersson]

Hello all,

let me point out three deficiencies of Inetd, being due to
incompleteness of the function fix_tcpmux().

  1. In a situation where a service entry for the internal
     service TCPMUX is being inserted by fix_tcpmux(), then
     the global node list is ignored, hence a universal listener
     is created for TCPMUX. Neither is a node list inherited
     from the named TCPMUX service. Consider these examples:

        # inetd.conf
        localhost:
        tcpmux/date stream tcp nowait nobody /bin/date date

     and

        # inetd2.conf
        localhost:tcpmux/date stream tcp nowait nobody /bin/date date
        this.computer:tcpmux/date stream tcp nowait nobody /bin/date date

     Both instances will initiate a default listener on '*:1'. The latter
     file illustrates the difficulty of inheriting a node list: Which list
     should be applied?


  2. In the same situation, the listener will allways initiate a listener
     for "tcp6", in spite of the services being specifies as "tcp".

  3. The default service generated in fix_tcpmux() still suffers by the
     incorrect flag AI_V4MAPPED in FreeBSD. Observe that AI_V4MAPPED is
     defined in the header file <netdb.h> of FreeBSD, but that the manpage
     getaddrinfo(3) does not mention this flag. It is therefore not elementary
     to say whether FreeBSD allows the use of this flag, or if its activation
     will always result in a failed resolved call.

Best regards,
Mats