xauth



XAUTH(1)                                                              XAUTH(1)




NAME

       xauth - X authority file utility


SYNOPSIS

       xauth [ -f authfile ] [ -vqibn ] [ command arg ... ]


DESCRIPTION

       The  xauth program is used to edit and display the authorization infor-
       mation used in connecting to the X server.   This  program  is  usually
       used  to  extract authorization records from one machine and merge them
       in on another (as is the case when  using  remote  logins  or  granting
       access  to  other  users).   Commands  (described below) may be entered
       interactively, on the xauth command line, or  in  scripts.   Note  that
       this  program  does  not  contact the X server except when the generate
       command is used.  Normally xauth is not used to  create  the  authority
       file entry in the first place; xdm does that.


OPTIONS

       The  following options may be used with xauth.  They may be given indi-
       vidually (e.g., -q -i) or may combined (e.g., -qi).

       -f authfile
               This option specifies the name of the authority  file  to  use.
               By default, xauth will use the file specified by the XAUTHORITY
               environment variable or .Xauthority in the user’s  home  direc-
               tory.

       -q      This option indicates that xauth should operate quietly and not
               print unsolicited status messages.  This is the default  if  an
               xauth  command  is is given on the command line or if the stan-
               dard output is not directed to a terminal.

       -v      This option indicates that xauth should operate  verbosely  and
               print  status messages indicating the results of various opera-
               tions (e.g., how many records have  been  read  in  or  written
               out).   This  is  the default if xauth is reading commands from
               its standard input and its standard output  is  directed  to  a
               terminal.

       -i      This  option  indicates  that xauth should ignore any authority
               file locks.  Normally, xauth will refuse to read  or  edit  any
               authority  files  that have been locked by other programs (usu-
               ally xdm or another xauth).

       -b      This option indicates that xauth should attempt  to  break  any
               authority  file  locks before proceeding.  Use this option only
               to clean up stale locks.

       -n      This option indicates that xauth should not attempt to  resolve
               any  hostnames, but should simply always print the host address
               as stored in the authority file.


COMMANDS

       The following commands may be used to manipulate authority files:

       add displayname protocolname hexkey
               An authorization entry for  the  indicated  display  using  the
               given protocol and key data is added to the authorization file.
               The data is specified as an even-lengthed string of hexadecimal
               digits,  each  pair representing one octet.  The first digit of
               each pair gives the most significant 4 bits of the  octet,  and
               the  second  digit  of  the  pair gives the least significant 4
               bits.  For example, a 32 character  hexkey  would  represent  a
               128-bit  value.   A  protocol  name consisting of just a single
               period is treated as an abbreviation for MIT-MAGIC-COOKIE-1.


       generate displayname protocolname [trusted|untrusted]
               [timeout seconds] [group group-id] [data hexdata]

               This command is similar to add.  The main  difference  is  that
               instead  of  requiring the user to supply the key data, it con-
               nects to the server specified in displayname and uses the SECU-
               RITY  extension  in  order  to get the key data to store in the
               authorization file.  If the server cannot be contacted or if it
               does  not  support  the  SECURITY extension, the command fails.
               Otherwise, an authorization entry  for  the  indicated  display
               using the given protocol is added to the authorization file.  A
               protocol name consisting of just a single period is treated  as
               an abbreviation for MIT-MAGIC-COOKIE-1.

               If  the trusted option is used, clients that connect using this
               authorization will have full run of the display, as usual.   If
               untrusted  is  used, clients that connect using this authoriza-
               tion will be considered untrusted and prevented  from  stealing
               or  tampering  with data belonging to trusted clients.  See the
               SECURITY  extension  specification  for  full  details  on  the
               restrictions  imposed  on  untrusted  clients.   The default is
               untrusted.

               The timeout option specifies how long in  seconds  this  autho-
               rization  will  be  valid.  If the authorization remains unused
               (no clients are connected with it) for longer  than  this  time
               period,   the  server  purges  the  authorization,  and  future
               attempts to connect using it will fail.  Note that the  purging
               done by the server does not delete the authorization entry from
               the authorization file.  The default timeout is 60 seconds.

               The group option specifies the application group  that  clients
               connecting  with  this authorization should belong to.  See the
               application group extension  specification  for  more  details.
               The default is to not belong to an application group.

               The  data  option  specifies data that the server should use to
               generate the authorization.  Note that this  is  not  the  same
               data  that  gets written to the authorization file.  The inter-
               pretation of this data depends on the  authorization  protocol.
               The  hexdata  is  in the same format as the hexkey described in
               the add command.  The default is to send no data.


       [n]extract filename displayname...
               Authorization entries for each of the  specified  displays  are
               written  to  the  indicated  file.   If the nextract command is
               used, the entries are written in a numeric format suitable  for
               non-binary  transmission (such as secure electronic mail).  The
               extracted entries can be read  back  in  using  the  merge  and
               nmerge  commands.   If  the  filename consists of just a single
               dash, the entries will be written to the standard output.

       [n]list [displayname...]
               Authorization entries for each of the  specified  displays  (or
               all  if no displays are named) are printed on the standard out-
               put.  If the nlist command is used, entries will  be  shown  in
               the  numeric  format  used  by the nextract command; otherwise,
               they are shown in a textual format.  Key data  is  always  dis-
               played  in  the  hexadecimal format given in the description of
               the add command.

       [n]merge [filename...]
               Authorization entries are read from the specified files and are
               merged  into the authorization database, superceding any match-
               ing existing entries.  If  the  nmerge  command  is  used,  the
               numeric  format given in the description of the extract command
               is used.  If a filename consists of just  a  single  dash,  the
               standard input will be read if it hasn’t been read before.

       remove displayname...
               Authorization  entries  matching  the  specified  displays  are
               removed from the authority file.

       source filename
               The specified file is treated as a script containing xauth com-
               mands to execute.  Blank lines and lines beginning with a sharp
               sign (#) are ignored.  A single dash may be  used  to  indicate
               the standard input, if it hasn’t already been read.

       info    Information  describing  the authorization file, whether or not
               any changes have been made, and from where xauth  commands  are
               being read is printed on the standard output.

       exit    If  any  modifications  have  been  made, the authority file is
               written out (if allowed), and the program  exits.   An  end  of
               file is treated as an implicit exit command.

       quit    The  program  exits, ignoring any modifications.  This may also
               be accomplished by pressing the interrupt character.

       help [string]
               A description of all commands that begin with the given  string
               (or all commands if no string is given) is printed on the stan-
               dard output.

       ?       A short list of the valid commands is printed on  the  standard
               output.


DISPLAY NAMES

       Display  names  for  the add, [n]extract, [n]list, [n]merge, and remove
       commands use the same format as the DISPLAY  environment  variable  and
       the  common  -display command line argument.  Display-specific informa-
       tion (such as the screen number) is unnecessary and  will  be  ignored.
       Same-machine  connections  (such  as local-host sockets, shared memory,
       and the Internet Protocol hostname localhost) are referred to as  host-
       name/unix:displaynumber  so  that  local entries for different machines
       may be stored in one authority file.


EXAMPLE

       The most common use for xauth is to extract the entry for  the  current
       display,  copy  it  to  another  machine,  and merge it into the user’s
       authority file on the remote machine:

               %  xauth extract - $DISPLAY | rsh otherhost xauth merge -


       The following command contacts the server :0 to create an authorization
       using  the MIT-MAGIC-COOKIE-1 protocol.  Clients that connect with this
       authorization will be untrusted.
            %  xauth generate :0 .


ENVIRONMENT

       This xauth program uses the following environment variables:

       XAUTHORITY
               to get the name of the authority file to use if the  -f  option
               isn’t used.

       HOME    to get the user’s home directory if XAUTHORITY isn’t defined.


FILES

       $HOME/.Xauthority
               default authority file if XAUTHORITY isn’t defined.


BUGS

       Users  that  have  unsecure  networks should take care to use encrypted
       file  transfer  mechanisms  to  copy  authorization   entries   between
       machines.   Similarly, the MIT-MAGIC-COOKIE-1 protocol is not very use-
       ful in unsecure environments.  Sites that are interested in  additional
       security  may  need  to  use encrypted authorization mechanisms such as
       Kerberos.

       Spaces are currently not allowed in the protocol name.   Quoting  could
       be added for the truly perverse.


AUTHOR

       Jim Fulton, MIT X Consortium



                                                                      XAUTH(1)

Man(1) output converted with man2html