@c wks.texi - man pages for the Web Key Service tools.
@c Copyright (C) 2017 g10 Code GmbH
@c Copyright (C) 2017 Bundesamt für Sicherheit in der Informationstechnik
@c This is part of the GnuPG manual.
@c For copying conditions, see the file GnuPG.texi.

@include defs.inc

@node Web Key Service
@chapter Web Key Service

GnuPG comes with tools used to maintain and access a Web Key
Directory.

@menu
* gpg-wks-client::        Send requests via WKS
* gpg-wks-server::        Server to provide the WKS.
@end menu

@c
@c  GPG-WKS-CLIENT
@c
@manpage gpg-wks-client.1
@node gpg-wks-client
@section Send requests via WKS
@ifset manverb
.B gpg-wks-client
\- Client for the Web Key Service
@end ifset

@mansect synopsis
@ifset manverb
.B gpg-wks-client
.RI [ options ]
.B \-\-supported
.I user-id
.br
.B gpg-wks-client
.RI [ options ]
.B \-\-check
.I user-id
.br
.B gpg-wks-client
.RI [ options ]
.B \-\-create
.I fingerprint
.I user-id
.br
.B gpg-wks-client
.RI [ options ]
.B \-\-receive
.br
.B gpg-wks-client
.RI [ options ]
.B \-\-read
@end ifset

@mansect description
The @command{gpg-wks-client} is used to send requests to a Web Key
Service provider.  This is usuallay done to upload a key into a Web
Key Directory.

With the @option{--supported} command the caller can test whether a
site supports the Web Key Service.  The argument is an arbitray
address in the to be tested domain. For example
@file{foo@@example.net}.  The command returns success if the Web Key
Service is supported.  The operation is silent; to get diagnostic
output use the option @option{--verbose}.

With the @option{--check} command the caller can test whether a key
exists for a supplied mail address.  The command returns success if a
key is available.

The @option{--create} command is used to send a request for
publication in the Web Key Directory.  The arguments are the
fingerprint of the key and the user id to publish.  The output from
the command is a properly formatted mail with all standard headers.
This mail can be fed to @command{sendmail(8)} or any other tool to
actually send that mail.  If @command{sendmail(8)} is installed the
option @option{--send} can be used to directly send the created
request.  If the provider request a 'mailbox-only' user id and no such
user id is found, @command{gpg-wks-client} will try an additional user
id.

The @option{--receive} and @option{--read} commands are used to
process confirmation mails as send from the service provider.  The
former expects an encrypted MIME messages, the latter an already
decrypted MIME message.  The result of these commands are another mail
which can be send in the same way as the mail created with
@option{--create}.

@command{gpg-wks-client} is not commonly invoked directly and thus it
is not installed in the bin directory.  Here is an example how it can
be invoked manually to check for a Web Key Directory entry for
@file{foo@@example.org}:

@example
$(gpgconf --list-dirs libexecdir)/gpg-wks-client --check foo@@example.net
@end example

@mansect options
@noindent
@command{gpg-wks-client} understands these options:

@table @gnupgtabopt

@item --send
@opindex send
Directly send created mails using the @command{sendmail} command.
Requires installation of that command.

@item --output @var{file}
@itemx -o
@opindex output
Write the created mail to @var{file} instead of stdout.  Note that the
value @code{-} for @var{file} is the same as writing to stdout.

@item --status-fd @var{n}
@opindex status-fd
Write special status strings to the file descriptor @var{n}.
This program returns only the status messages SUCCESS or FAILURE which
are helpful when the caller uses a double fork approach and can't
easily get the return code of the process.

@item --verbose
@opindex verbose
Enable extra informational output.

@item --quiet
@opindex quiet
Disable almost all informational output.

@item --version
@opindex version
Print version of the program and exit.

@item --help
@opindex help
Display a brief help page and exit.

@end table


@mansect see also
@ifset isman
@command{gpg-wks-server}(1)
@end ifset


@c
@c  GPG-WKS-SERVER
@c
@manpage gpg-wks-server.1
@node gpg-wks-server
@section Provide the Web Key Service
@ifset manverb
.B gpg-wks-server
\- Server providing the Web Key Service
@end ifset

@mansect synopsis
@ifset manverb
.B gpg-wks-server
.RI [ options ]
.B \-\-receive
.br
.B gpg-wks-server
.RI [ options ]
.B \-\-cron
.br
.B gpg-wks-server
.RI [ options ]
.B \-\-list-domains
.br
.B gpg-wks-server
.RI [ options ]
.B \-\-install-key
.I file
.br
.B gpg-wks-server
.RI [ options ]
.B \-\-remove-key
.I mailaddr
.br
.B gpg-wks-server
.RI [ options ]
.B \-\-revoke-key
.I mailaddr
@end ifset

@mansect description
The @command{gpg-wks-server} is a server site implementation of the
Web Key Service.  It receives requests for publication, sends
confirmation requests, receives confirmations, and published the key.
It also has features to ease the setup and maintenance of a Web Key
Directory.

When used with the command @option{--receive} a single Web Key Service
mail is processed.  Commonly this command is used with the option
@option{--send} to directly send the crerated mails back.  See below
for an installation example.

The command @option{--cron} is used for regualr cleanup tasks.  For
example non-confirmed requested should be removed after their expire
time.  It is best to run this command once a day from a cronjob.

The command @option{--list-domains} prints all configured domains.
Further it creates missing directories for the configuration and
prints warnings pertaining to problems in the configuration.

The commands @option{--install-key}, @option{--remove-key}, and
@option{--revoke-key} are not yet functional.


@mansect options
@noindent
@command{gpg-wks-server} understands these options:

@table @gnupgtabopt

@item --from @var{mailaddr}
@opindex from
Use @var{mailaddr} as the default sender address.

@item --header @var{name}=@var{value}
@opindex header
Add the mail header "@var{name}: @var{value}" to all outgoing mails.

@item --send
@opindex send
Directly send created mails using the @command{sendmail} command.
Requires installation of that command.

@item --output @var{file}
@itemx -o
@opindex output
Write the created mail also to @var{file}. Note that the value
@code{-} for @var{file} would write it to stdout.

@item --verbose
@opindex verbose
Enable extra informational output.

@item --quiet
@opindex quiet
Disable almost all informational output.

@item --version
@opindex version
Print version of the program and exit.

@item --help
@opindex help
Display a brief help page and exit.

@end table

@noindent
@mansect examples
@chapheading Examples

The Web Key Service requires a working directory to store keys
pending for publication.  As root create a working directory:

@example
  # mkdir /var/lib/gnupg/wks
  # chown webkey:webkey /var/lib/gnupg/wks
  # chmod 2750 /var/lib/gnupg/wks
@end example

Then under your webkey account create directories for all your
domains.  Here we do it for "example.net":

@example
  $ mkdir /var/lib/gnupg/wks/example.net
@end example

Finally run

@example
  $ gpg-wks-server --list-domains
@end example

to create the required sub-directories with the permission set
correctly.  For each domain a submission address needs to be
configured.  All service mails are directed to that address.  It can
be the same address for all configured domains, for example:

@example
  $ cd /var/lib/gnupg/wks/example.net
  $ echo key-submission@@example.net >submission-address
@end example

The protocol requires that the key to be published is sent with an
encrypted mail to the service.  Thus you need to create a key for
the submission address:

@example
  $ gpg --batch --passphrase '' --quick-gen-key key-submission@@example.net
  $ gpg --with-wkd-hash -K key-submission@@example.net
@end example

The output of the last command looks similar to this:

@example
  sec   rsa2048 2016-08-30 [SC]
        C0FCF8642D830C53246211400346653590B3795B
  uid           [ultimate] key-submission@@example.net
                bxzcxpxk8h87z1k7bzk86xn5aj47intu@@example.net
  ssb   rsa2048 2016-08-30 [E]
@end example

Take the hash of the string "key-submission", which is
"bxzcxpxk8h87z1k7bzk86xn5aj47intu" and manually publish that key:

@example
  $ gpg --export-options export-minimal --export \
  >  -o /var/lib/gnupg/wks/example.net/hu/bxzcxpxk8h87z1k7bzk86xn5aj47intu \
  >  key-submission@@example.new
@end example

Make sure that the created file is world readable.

Finally that submission address needs to be redirected to a script
running @command{gpg-wks-server}.  The @command{procmail} command can
be used for this: Redirect the submission address to the user "webkey"
and put this into webkey's @file{.procmailrc}:

@example
:0
* !^From: webkey@@example.net
* !^X-WKS-Loop: webkey.example.net
|gpg-wks-server -v --receive \
     --header X-WKS-Loop=webkey.example.net \
     --from webkey@@example.net --send
@end example


@mansect see also
@ifset isman
@command{gpg-wks-client}(1)
@end ifset