Provided by: ax25-tools_0.0.10-rc4-1_i386 bug

NAME

       axspawn - Allow automatic login to a Linux system.

SYNOPSIS

       axspawn [--pwprompt PR0MPT, -p PR0MPT] [--changeuser, -c] [--rootlogin,
       -r] [--only-md5] [--wait, -w]

DESCRIPTION

       Axspawn will check if the peer is an  AX.25  connect,  the  callsign  a
       valid  Amateur  Radio  callsign,  strip  the SSID, check if UID/GID are
       valid, allow a password-less login if the password-entry in /etc/passwd
       is “+” or empty; in every other case login will prompt for a password.

       Axspawn  can  create  user  accounts automatically. You may specify the
       user shell, first and maximum user id, group ID in the config file  and
       (unlike  WAMPES)  create  a file “/etc/ax25/ax25.profile” which will be
       copied to ~/.profile.

SECURITY

       Auto accounting is a security problem  by  definition.  Unlike  WAMPES,
       which  creates  an  empty  password field, Axspawn adds an “impossible”
       ('+') password to /etc/passwd. Login gets called with the “-f”  option,
       thus  new  users  have the chance to login without a password. (I guess
       this won't work with the shadow password system).

       Of course axspawn does callsign checking: Only letters and numbers  are
       allowed, the callsign must be longer than 4 characters and shorter than
       6 characters (without SSID). There must be at least one digit, and max.
       two  digits within the call. The SSID must be within the range of 0 and
       15. Please drop me a note if you know a valid  Amateur  Radio  callsign
       that  does  not  fit this pattern _and_ can be represented correctly in
       AX.25.

       axspawn also has the well known authentication mechanisms of the  AX.25
       bbs   baycom   (sys)   and   md5   standards.    axspawn   searches  in
       /etc/ax25/bcpasswd (first) and ~user/.bcpasswd (second) for a match  of
       the  required  authentication  mechanism  and password.  md5 and baycom
       passwords may differ. md5 passwords gain over baycom passwords.

       Note: you could "lock" special "friends" out  by  specifying  an  empty
       password  in  /etc/ax25/bcpasswd (line "n0call:md5:"). -> md5 Passwords
       are enforced. But the length is shorter than the  minimum  (len  8  for
       md5,  len  20 for baycom); user's password file is not searched because
       in /etc/ax25/bcpasswd its already found..

       Syntax and caveeats for /etc/ax25/bcpasswd:
         - Has to be a regular file (no symlink). Not world-readable/writable.
         - Example lines:
           # Thomas
           dl9sau:md5:abcdefgh
           # Test
           te1st:sys:12345678901234567890
           # root
           root:md5:ziz7AoxuAt6jeuthTheexet0uDa9iefuAeph3eelAetahmi0
           # misconfiguration:
           thisbadlineisignored
           # With this line
           systempasswordonly
           # .. axspan will not look in user's homedir for his .bcpasswd

       Syntax and caveeats for user's .bcpasswd in his $HOME:
         - Has to be a regular file (no symlink). Neither group- nor world-
             read-/writable. Has to be owned by the user or uid 0 (root).
         - Example lines:
           # could be shorter
           md5:abcdefgh
           # should be longer
           sys:12345678901234567890

OPTIONS

       -p DB0FHN or --pwprompt DB0FHN
            While baycom or  md5  password  authentication  (see  above),  the
            password  prompt  is  set  to  the  first argument (DB0FHN in this
            example). This  may  be  needed  for  some  packet-radio  terminal
            programs for detecting the password prompt properly.

       -c, --changeuser
            Allow  connecting  ax25  users to change their username for login.
            They'll be asked for their real login name.

       -e, --embedded
            Special treatment for axspawn  on  non-standard  conform  embedded
            devices.   I.e. openwrt has no true /bin/login: if you use it as a
            real login program, it raises a security hole.

       -r, --rootlogin
            Permit login as user root. Cave:  only  md5  or  baycom  style  is
            allowed; no plaintext password.

       --only-md5
            Insist  in md5 authentication during login. If no password for the
            user is found, or it is not md5, then no other login mechanism  is
            granted.   This  option,  in  combination with -c and -r, may be a
            useful configuration for systems where no ax25 user  accounts  are
            available,  but you as sysop would like to have a login access for
            your administrative tasks.

       -w, --wait
            Eats the first line the user sends. This feature is useful if  you
            have  TCP  VC  connects to the same Call+SSID. It is now obsolete,
            because ax25d is the right place  for  this  and  implements  this
            functionality better.

       Theses  are  options  and not part of the preferences because you _may_
       like to have on every interface definition in ax25d.conf (where axspawn
       is started from) a different behaviour.

FILES

       /etc/passwd
       /etc/ax25/ax25.profile
       /etc/ax25/axspawn.conf
       /etc/ax25/bcpasswd
       ~/.bcpasswd

SEE ALSO

       axspawn.conf(5), ax25d(8).

AUTHOR

       Joerg Reuter DL1BKE <jreuter@poboxes.com>