@c This is part of the GnuPG manual.
@c For copying conditions, see the file gnupg.texi.
-@c Note that we use this texinfo file for all versions of GnuPG:
-@c 2.0 and 2.1. The macro "gpgtwoone" controls parts which are only
-@c valid for GnuPG 2.1 and later.
-
+@include defs.inc
@node Invoking GPG-AGENT
@chapter Invoking GPG-AGENT
@command{gpg} and @command{gpgsm} as well as for a couple of other
utilities.
-@ifset gpgtwoone
The agent is automatically started on demand by @command{gpg},
@command{gpgsm}, @command{gpgconf}, or @command{gpg-connect-agent}.
Thus there is no reason to start it manually. In case you want to use
the included Secure Shell Agent you may start the agent using:
-@example
-gpg-connect-agent /bye
-@end example
-@end ifset
-
-@ifclear gpgtwoone
-@noindent
-The usual way to run the agent is from the @code{~/.xsession} file:
+@c From dkg on gnupg-devel on 2016-04-21:
+@c
+@c Here's an attempt at writing a short description of the goals of an
+@c isolated cryptographic agent:
+@c
+@c A cryptographic agent should control access to secret key material.
+@c The agent permits use of the secret key material by a supplicant
+@c without providing a copy of the secret key material to the supplicant.
+@c
+@c An isolated cryptographic agent separates the request for use of
+@c secret key material from permission for use of secret key material.
+@c That is, the system or process requesting use of the key (the
+@c "supplicant") can be denied use of the key by the owner/operator of
+@c the agent (the "owner"), which the supplicant has no control over.
+@c
+@c One way of enforcing this split is a per-key or per-session
+@c passphrase, known only by the owner, which must be supplied to the
+@c agent to permit the use of the secret key material. Another way is
+@c with an out-of-band permission mechanism (e.g. a button or GUI
+@c interface that the owner has access to, but the supplicant does not).
+@c
+@c The rationale for this separation is that it allows access to the
+@c secret key to be tightly controled and audited, and it doesn't permit
+@c the the supplicant to either copy the key or to override the owner's
+@c intentions.
@example
-eval $(gpg-agent --daemon)
+gpg-connect-agent /bye
@end example
-@noindent
-If you don't use an X server, you can also put this into your regular
-startup file @code{~/.profile} or @code{.bash_profile}. It is best not
-to run multiple instance of the @command{gpg-agent}, so you should make
-sure that only one is running: @command{gpg-agent} uses an environment
-variable to inform clients about the communication parameters. You can
-write the content of this environment variable to a file so that you can
-test for a running agent. Here is an example using Bourne shell syntax:
-
-@smallexample
-gpg-agent --daemon --enable-ssh-support \
- --write-env-file "$@{HOME@}/.gpg-agent-info"
-@end smallexample
-
-This code should only be run once per user session to initially fire up
-the agent. In the example the optional support for the included Secure
-Shell agent is enabled and the information about the agent is written to
-a file in the HOME directory. Note that by running gpg-agent without
-arguments you may test whether an agent is already running; however such
-a test may lead to a race condition, thus it is not suggested.
-
-@noindent
-The second script needs to be run for each interactive session:
-
-@smallexample
-if [ -f "$@{HOME@}/.gpg-agent-info" ]; then
- . "$@{HOME@}/.gpg-agent-info"
- export GPG_AGENT_INFO
- export SSH_AUTH_SOCK
-fi
-@end smallexample
-
-@noindent
-It reads the data out of the file and exports the variables. If you
-don't use Secure Shell, you don't need the last two export statements.
-@end ifclear
@noindent
+@efindex GPG_TTY
You should always add the following lines to your @code{.bashrc} or
whatever initialization file is used for all shell invocations:
under the default filename (which is system dependent) or use the
option @option{pinentry-program} to specify the full name of that program.
It is often useful to install a symbolic link from the actual used
-pinentry (e.g. @file{/usr/bin/pinentry-gtk}) to the expected
-one (e.g. @file{/usr/bin/pinentry}).
+pinentry (e.g. @file{@value{BINDIR}/pinentry-gtk}) to the expected
+one (e.g. @file{@value{BINDIR}/pinentry}).
@manpause
@noindent
@opindex daemon
Start the gpg-agent as a daemon; that is, detach it from the console
and run it in the background.
-@ifclear gpgtwoone
-Because @command{gpg-agent} prints out
-important information required for further use, a common way of
-invoking gpg-agent is: @code{eval $(gpg-agent --daemon)} to setup the
-environment variables. The option @option{--write-env-file} is
-another way commonly used to do this.
-@end ifclear
-Yet another way is creating
-a new process as a child of gpg-agent: @code{gpg-agent --daemon
-/bin/sh}. This way you get a new shell with the environment setup
-properly; if you exit from this shell, gpg-agent terminates as well.
+
+As an alternative you may create a new process as a child of
+gpg-agent: @code{gpg-agent --daemon /bin/sh}. This way you get a new
+shell with the environment setup properly; after you exit from this
+shell, gpg-agent terminates within a few seconds.
@end table
@mansect options
This option inhibits the use of the very secure random quality level
(Libgcrypt’s @code{GCRY_VERY_STRONG_RANDOM}) and degrades all request
down to standard random quality. It is only used for testing and
-shall not be used for any production quality keys. This option is
+should not be used for any production quality keys. This option is
only effective when given on the command line.
+On GNU/Linux, another way to quickly generate insecure keys is to use
+@command{rngd} to fill the kernel's entropy pool with lower quality
+random data. @command{rngd} is typically provided by the
+@command{rng-tools} package. It can be run as follows: @samp{sudo
+rngd -f -r /dev/urandom}.
+
@item --debug-pinentry
@opindex debug-pinentry
This option enables extra debug information pertaining to the
@itemx --csh
@opindex sh
@opindex csh
+@efindex SHELL
Format the info output in daemon mode for use with the standard Bourne
shell or the C-shell respectively. The default is to guess it based on
the environment variable @code{SHELL} which is correct in almost all
cases.
-@ifclear gpgtwoone
-@item --write-env-file @var{file}
-@opindex write-env-file
-Often it is required to connect to the agent from a process not being an
-inferior of @command{gpg-agent} and thus the environment variable with
-the socket name is not available. To help setting up those variables in
-other sessions, this option may be used to write the information into
-@var{file}. If @var{file} is not specified the default name
-@file{$@{HOME@}/.gpg-agent-info} will be used. The format is suitable
-to be evaluated by a Bourne shell like in this simple example:
-
-@example
-eval $(cat @var{file})
-eval $(cut -d= -f 1 < @var{file} | xargs echo export)
-@end example
-@end ifclear
-
@item --no-grab
@opindex no-grab
@anchor{option --log-file}
@item --log-file @var{file}
@opindex log-file
+@efindex HKCU\Software\GNU\GnuPG:DefaultLogFile
Append all logging output to @var{file}. This is very helpful in seeing
what the agent actually does. If neither a log file nor a log file
descriptor has been set on a Windows platform, the Registry entry
This option allows the use of @command{gpg-preset-passphrase} to seed the
internal cache of @command{gpg-agent} with passphrases.
-@ifset gpgtwoone
-@anchor{option --allow-loopback-pinentry}
+@anchor{option --no-allow-loopback-pinentry}
+@item --no-allow-loopback-pinentry
@item --allow-loopback-pinentry
+@opindex no-allow-loopback-pinentry
@opindex allow-loopback-pinentry
-Allow clients to use the loopback pinentry features; see the option
-@option{pinentry-mode} for details.
-@end ifset
+Disallow or allow clients to use the loopback pinentry features; see
+the option @option{pinentry-mode} for details. Allow is the default.
+
+The @option{--force} option of the Assuan command @command{DELETE_KEY}
+is also controlled by this option: The option is ignored if a loopback
+pinentry is disallowed.
-@ifset gpgtwoone
@item --no-allow-external-cache
@opindex no-allow-external-cache
Tell Pinentry not to enable features which use an external cache for
which employs an additional external cache to implement such a policy.
By using this option the Pinentry is advised not to make use of such a
cache and instead always ask the user for the requested passphrase.
-@end ifset
+
+@item --allow-emacs-pinentry
+@opindex allow-emacs-pinentry
+Tell Pinentry to allow features to divert the passphrase entry to a
+running Emacs instance. How this is exactly handled depends on the
+version of the used Pinentry.
@item --ignore-cache-for-signing
@opindex ignore-cache-for-signing
@item --default-cache-ttl @var{n}
@opindex default-cache-ttl
-Set the time a cache entry is valid to @var{n} seconds. The default is
-600 seconds.
+Set the time a cache entry is valid to @var{n} seconds. The default
+is 600 seconds. Each time a cache entry is accessed, the entry's
+timer is reset. To set an entry's maximum lifetime, use
+@command{max-cache-ttl}.
@item --default-cache-ttl-ssh @var{n}
@opindex default-cache-ttl
Set the time a cache entry used for SSH keys is valid to @var{n}
-seconds. The default is 1800 seconds.
+seconds. The default is 1800 seconds. Each time a cache entry is
+accessed, the entry's timer is reset. To set an entry's maximum
+lifetime, use @command{max-cache-ttl-ssh}.
@item --max-cache-ttl @var{n}
@opindex max-cache-ttl
@opindex enable-passphrase-history
This option does nothing yet.
+@item --pinentry-invisible-char @var{char}
+@opindex pinentry-invisible-char
+This option asks the Pinentry to use @var{char} for displaying hidden
+characters. @var{char} must be one character UTF-8 string. A
+Pinentry may or may not honor this request.
+
+@item --pinentry-timeout @var{n}
+@opindex pinentry-timeout
+This option asks the Pinentry to timeout after @var{n} seconds with no
+user input. The default value of 0 does not ask the pinentry to
+timeout, however a Pinentry may use its own default timeout value in
+this case. A Pinentry may or may not honor this request.
+
@item --pinentry-program @var{filename}
@opindex pinentry-program
Use program @var{filename} as the PIN entry. The default is
the default pinentry is @file{pinentry}; if that file does not exist
but a @file{pinentry-basic} exist the latter is used.
+On a Windows platform the default is to use the first existing program
+from this list:
+@file{bin\pinentry.exe},
+@file{..\Gpg4win\bin\pinentry.exe},
+@file{..\Gpg4win\pinentry.exe},
+@file{..\GNU\GnuPG\pinentry.exe},
+@file{..\GNU\bin\pinentry.exe},
+@file{bin\pinentry-basic.exe}
+where the file names are relative to the GnuPG installation directory.
+
+
@item --pinentry-touch-file @var{filename}
@opindex pinentry-touch-file
By default the filename of the socket gpg-agent is listening for
disabling the ability to do smartcard operations. Note, that enabling
this option at runtime does not kill an already forked scdaemon.
-@ifset gpgtwoone
@item --disable-check-own-socket
@opindex disable-check-own-socket
@command{gpg-agent} employs a periodic self-test to detect a stolen
has taken over the socket and @command{gpg-agent} will then terminate
itself. This option may be used to disable this self-test for
debugging purposes.
-@end ifset
@item --use-standard-socket
@itemx --no-use-standard-socket
@opindex use-standard-socket
@opindex no-use-standard-socket
@opindex use-standard-socket-p
-@ifset gpgtwoone
Since GnuPG 2.1 the standard socket is always used. These options
have no more effect. The command @code{gpg-agent
--use-standard-socket-p} will thus always return success.
-@end ifset
-@ifclear gpgtwoone
-By enabling this option @command{gpg-agent} will listen on the socket
-named @file{S.gpg-agent}, located in the home directory, and not create
-a random socket below a temporary directory. Tools connecting to
-@command{gpg-agent} should first try to connect to the socket given in
-environment variable @var{GPG_AGENT_INFO} and then fall back to this
-socket. This option may not be used if the home directory is mounted on
-a remote file system which does not support special files like fifos or
-sockets.
-
-Note, that @option{--use-standard-socket} is the default on
-Windows systems.
-
-The default may be changed at build time. It is
-possible to test at runtime whether the agent has been configured for
-use with the standard socket by issuing the command @command{gpg-agent
---use-standard-socket-p} which returns success if the standard socket
-option has been enabled.
-@end ifclear
@item --display @var{string}
@itemx --ttyname @var{string}
@anchor{option --enable-ssh-support}
@item --enable-ssh-support
+@itemx --enable-putty-support
@opindex enable-ssh-support
+@opindex enable-putty-support
Enable the OpenSSH Agent protocol.
Adding the @option{--verbose} shows the progress of starting the agent.
+The @option{--enable-putty-support} is only available under Windows
+and allows the use of gpg-agent with the ssh implementation
+@command{putty}. This is similar to the regular ssh-agent support but
+makes use of Windows message queue as required by @command{putty}.
+
+
@end table
All the long options may also be given in the configuration file after
@table @file
@item gpg-agent.conf
-@cindex gpg-agent.conf
+@efindex gpg-agent.conf
This is the standard configuration file read by @command{gpg-agent} on
startup. It may contain any valid long option; the leading
two dashes may not be entered and the option may not be abbreviated.
You should backup this file.
@item trustlist.txt
+@efindex trustlist.txt
This is the list of trusted keys. You should backup this file.
Comment lines, indicated by a leading hash mark, as well as empty
that this file can't be changed inadvertently.
As a special feature a line @code{include-default} will include a global
-list of trusted certificates (e.g. @file{/etc/gnupg/trustlist.txt}).
+list of trusted certificates (e.g. @file{@value{SYSCONFDIR}/trustlist.txt}).
This global list is also used if the local list is not available.
It is possible to add further flags after the @code{S} for use by the
@item sshcontrol
-@cindex sshcontrol
+@efindex sshcontrol
This file is used when support for the secure shell agent protocol has
been enabled (@pxref{option --enable-ssh-support}). Only keys present in
this file are used in the SSH protocol. You should backup this file.
@end cartouche
@item private-keys-v1.d/
+@efindex private-keys-v1.d
This is the directory where gpg-agent stores the private keys. Each
key is stored in a file with the name made up of the keygrip and the
@end table
Note that on larger installations, it is useful to put predefined
-files into the directory @file{/etc/skel/.gnupg/} so that newly created
+files into the directory @file{@value{SYSCONFSKELDIR}} so that newly created
users start up with a working configuration. For existing users the
a small helper script is provided to create these files (@pxref{addgnupghome}).
again. Only certain options are honored: @code{quiet},
@code{verbose}, @code{debug}, @code{debug-all}, @code{debug-level},
@code{debug-pinentry},
-@code{no-grab}, @code{pinentry-program}, @code{default-cache-ttl},
+@code{no-grab},
+@code{pinentry-program},
+@code{pinentry-invisible-char},
+@code{default-cache-ttl},
@code{max-cache-ttl}, @code{ignore-cache-for-signing},
-@code{no-allow-external-cache},
+@code{no-allow-external-cache}, @code{allow-emacs-pinentry},
@code{no-allow-mark-trusted}, @code{disable-scdaemon}, and
@code{disable-check-own-socket}. @code{scdaemon-program} is also
supported but due to the current implementation, which calls the
@node Agent Examples
@section Examples
-@ifset gpgtwoone
-It is important to set the GPG_TTY environment variable in
+It is important to set the environment variable @code{GPG_TTY} in
your login shell, for example in the @file{~/.bashrc} init script:
@cartouche
@example
unset SSH_AGENT_PID
if [ "$@{gnupg_SSH_AUTH_SOCK_by:-0@}" -ne $$ ]; then
- export SSH_AUTH_SOCK="$@{HOME@}/.gnupg/S.gpg-agent.ssh"
+ export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)"
fi
@end example
@end cartouche
-@end ifset
-
-@ifclear gpgtwoone
-The usual way to invoke @command{gpg-agent} is
-
-@example
-$ eval $(gpg-agent --daemon)
-@end example
-
-An alternative way is by replacing @command{ssh-agent} with
-@command{gpg-agent}. If for example @command{ssh-agent} is started as
-part of the Xsession initialization, you may simply replace
-@command{ssh-agent} by a script like:
-
-@cartouche
-@example
-#!/bin/sh
-
-exec /usr/local/bin/gpg-agent --enable-ssh-support --daemon \
- --write-env-file $@{HOME@}/.gpg-agent-info "$@@"
-@end example
-@end cartouche
-@noindent
-and add something like (for Bourne shells)
-
-@cartouche
-@example
- if [ -f "$@{HOME@}/.gpg-agent-info" ]; then
- . "$@{HOME@}/.gpg-agent-info"
- export GPG_AGENT_INFO
- export SSH_AUTH_SOCK
- fi
-@end example
-@end cartouche
-
-@noindent
-to your shell initialization file (e.g. @file{~/.bashrc}).
-@end ifclear
@c
@c Assuan Protocol
@section Agent's Assuan Protocol
Note: this section does only document the protocol, which is used by
-GnuPG components; it does not deal with the ssh-agent protocol.
+GnuPG components; it does not deal with the ssh-agent protocol. To
+see the full specification of each command, use
-@ifset gpgtwoone
+@example
+ gpg-connect-agent 'help COMMAND' /bye
+@end example
+
+@noindent
+or just 'help' to list all available commands.
+
+@noindent
The @command{gpg-agent} daemon is started on demand by the GnuPG
components.
-@end ifset
-@ifclear gpgtwoone
-The @command{gpg-agent} should be started by the login shell and set an
-environment variable to tell clients about the socket to be used.
-Clients should deny to access an agent with a socket name which does
-not match its own configuration. An application may choose to start
-an instance of the gpg-agent if it does not figure that any has been
-started; it should not do this if a gpg-agent is running but not
-usable. Because @command{gpg-agent} can only be used in background mode, no
-special command line option is required to activate the use of the
-protocol.
-@end ifclear
To identify a key we use a thing called keygrip which is the SHA-1 hash
of an canonical encoded S-Expression of the public key as used in
different protocols, thereby saving space on the token used to keep the
secret keys.
-@ifset gpgtwoone
The @command{gpg-agent} may send status messages during a command or when
returning from a command to inform a client about the progress or result of an
operation. For example, the @var{INQUIRE_MAXLEN} status message may be sent
during a server inquire to inform the client of the maximum usable length of
the inquired data (which should not be exceeded).
-@end ifset
@menu
* Agent PKDECRYPT:: Decrypting a session key
* Agent ISTRUSTED:: Importing a Root Certificate
* Agent GET_PASSPHRASE:: Ask for a passphrase
* Agent CLEAR_PASSPHRASE:: Expire a cached passphrase
-@ifset gpgtwoone
* Agent PRESET_PASSPHRASE:: Set a passphrase for a keygrip
-@end ifset
* Agent GET_CONFIRMATION:: Ask for confirmation
* Agent HAVEKEY:: Check whether a key is available
* Agent LEARN:: Register a smartcard
of the PSE, a special export tool has to be used.
@example
-@ifset gpgtwoone
GENKEY [--no-protection] [--preset] [<cache_nonce>]
-@end ifset
-@ifclear gpgtwoone
- GENKEY
-@end ifclear
@end example
Invokes the key generation process and the server will then inquire
@end smallexample
@end cartouche
-@ifset gpgtwoone
The @option{--no-protection} option may be used to prevent prompting for a
passphrase to protect the secret key while leaving the secret key unprotected.
The @option{--preset} option may be used to add the passphrase to the cache
takes precedence over @option{--no-protection}; however if the client
sends a empty (zero-length) passphrase, this is identical to
@option{--no-protection}.
-@end ifset
@node Agent IMPORT
@subsection Importing a Secret Key
@subsection Ask for a passphrase
This function is usually used to ask for a passphrase to be used for
-conventional encryption, but may also be used by programs which need
+symmetric encryption, but may also be used by programs which need
special handling of passphrases. This command uses a syntax which helps
clients to use the agent with minimum effort.
Use this command to remove a cached passphrase.
@example
-@ifset gpgtwoone
CLEAR_PASSPHRASE [--mode=normal] <cache_id>
-@end ifset
-@ifclear gpgtwoone
- CLEAR_PASSPHRASE <cache_id>
-@end ifclear
@end example
-@ifset gpgtwoone
The @option{--mode=normal} option can be used to clear a @var{cache_id} that
was set by gpg-agent.
-@end ifset
-
-@ifset gpgtwoone
@node Agent PRESET_PASSPHRASE
@subsection Set a passphrase for a keygrip
number of seconds. A value of @code{-1} means infinate while @code{0} means
the default (currently only a timeout of -1 is allowed, which means to never
expire it).
-@end ifset
-
-
@node Agent GET_CONFIRMATION
@subsection Change a Passphrase
@example
-@ifset gpgtwoone
PASSWD [--cache-nonce=<c>] [--passwd-nonce=<s>] [--preset] @var{keygrip}
-@end ifset
-@ifclear gpgtwoone
- PASSWD @var{keygrip}
-@end ifclear
@end example
This command is used to interactively change the passphrase of the key
-identified by the hex string @var{keygrip}.
-
-@ifset gpgtwoone
-The @option{--preset} option may be used to add the new passphrase to the
-cache using the default cache parameters.
-@end ifset
+identified by the hex string @var{keygrip}. The @option{--preset}
+option may be used to add the new passphrase to the cache using the
+default cache parameters.
@node Agent UPDATESTARTUPTTY
This does not need any value. It is used to enable the
PINENTRY_LAUNCHED inquiry.
-@ifset gpgtwoone
@item pinentry-mode
This option is used to change the operation mode of the pinentry. The
following values are defined:
Use a loopback pinentry. This fakes a pinentry by using inquiries
back to the caller to ask for a passphrase. This option may only be
set if the agent has been configured for that.
- Use the @xref{option --allow-loopback-pinentry}.
+ To disable this feature use @xref{option --no-allow-loopback-pinentry}.
@end table
-@end ifset
-@ifset gpgtwoone
@item cache-ttl-opt-preset
This option sets the cache TTL for new entries created by GENKEY and
PASSWD commands when using the @option{--preset} option. It it is not
used a default value is used.
-@end ifset
-@ifset gpgtwoone
@item s2k-count
Instead of using the standard S2K count (which is computed on the
fly), the given S2K count is used for new keys or when changing the
option is valid for the entire session or until reset to 0. This
option is useful if the key is later used on boxes which are either
much slower or faster than the actual box.
-@end ifset
@end table
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