diff --git a/agent/genkey.c b/agent/genkey.c index 3ed63f663..0c91ab41a 100644 --- a/agent/genkey.c +++ b/agent/genkey.c @@ -1,621 +1,648 @@ /* genkey.c - Generate a keypair * Copyright (C) 2002, 2003, 2004, 2007, 2010 Free Software Foundation, Inc. * Copyright (C) 2015 g10 Code GmbH. * * This file is part of GnuPG. * * GnuPG is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 3 of the License, or * (at your option) any later version. * * GnuPG is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, see . */ #include #include #include #include #include #include #include "agent.h" #include "../common/i18n.h" #include "../common/exechelp.h" #include "../common/sysutils.h" static int store_key (gcry_sexp_t private, const char *passphrase, int force, unsigned long s2k_count, time_t timestamp) { int rc; unsigned char *buf; size_t len; unsigned char grip[20]; if ( !gcry_pk_get_keygrip (private, grip) ) { log_error ("can't calculate keygrip\n"); return gpg_error (GPG_ERR_GENERAL); } len = gcry_sexp_sprint (private, GCRYSEXP_FMT_CANON, NULL, 0); log_assert (len); buf = gcry_malloc_secure (len); if (!buf) return out_of_core (); len = gcry_sexp_sprint (private, GCRYSEXP_FMT_CANON, buf, len); log_assert (len); if (passphrase) { unsigned char *p; rc = agent_protect (buf, passphrase, &p, &len, s2k_count, -1); if (rc) { xfree (buf); return rc; } xfree (buf); buf = p; } rc = agent_write_private_key (grip, buf, len, force, NULL, NULL, timestamp); xfree (buf); return rc; } /* Count the number of non-alpha characters in S. Control characters and non-ascii characters are not considered. */ static size_t nonalpha_count (const char *s) { size_t n; for (n=0; *s; s++) if (isascii (*s) && ( isdigit (*s) || ispunct (*s) )) n++; return n; } /* Check PW against a list of pattern. Return 0 if PW does not match these pattern. If CHECK_CONSTRAINTS_NEW_SYMKEY is set in flags and --check-sym-passphrase-pattern has been configured, use the pattern file from that option. */ static int do_check_passphrase_pattern (ctrl_t ctrl, const char *pw, unsigned int flags) { gpg_error_t err = 0; const char *pgmname = gnupg_module_name (GNUPG_MODULE_NAME_CHECK_PATTERN); FILE *infp; const char *argv[10]; pid_t pid; int result, i; const char *pattern; + char *patternfname; (void)ctrl; pattern = opt.check_passphrase_pattern; if ((flags & CHECK_CONSTRAINTS_NEW_SYMKEY) && opt.check_sym_passphrase_pattern) pattern = opt.check_sym_passphrase_pattern; if (!pattern) return 1; /* Oops - Assume password should not be used */ + if (strchr (pattern, '/') || strchr (pattern, '\\') + || (*pattern == '~' && pattern[1] == '/')) + patternfname = make_absfilename_try (pattern, NULL); + else + patternfname = make_filename_try (gnupg_sysconfdir (), pattern, NULL); + if (!patternfname) + { + log_error ("error making filename from '%s': %s\n", + pattern, gpg_strerror (gpg_error_from_syserror ())); + return 1; /* Do not pass the check. */ + } + + /* Make debugging a broken config easier by printing a useful error + * message. */ + if (gnupg_access (patternfname, F_OK)) + { + log_error ("error accessing '%s': %s\n", + patternfname, gpg_strerror (gpg_error_from_syserror ())); + xfree (patternfname); + return 1; /* Do not pass the check. */ + } + infp = gnupg_tmpfile (); if (!infp) { err = gpg_error_from_syserror (); log_error (_("error creating temporary file: %s\n"), gpg_strerror (err)); + xfree (patternfname); return 1; /* Error - assume password should not be used. */ } if (fwrite (pw, strlen (pw), 1, infp) != 1) { err = gpg_error_from_syserror (); log_error (_("error writing to temporary file: %s\n"), gpg_strerror (err)); fclose (infp); + xfree (patternfname); return 1; /* Error - assume password should not be used. */ } fseek (infp, 0, SEEK_SET); clearerr (infp); i = 0; argv[i++] = "--null"; argv[i++] = "--", - argv[i++] = pattern, + argv[i++] = patternfname, argv[i] = NULL; log_assert (i < sizeof argv); if (gnupg_spawn_process_fd (pgmname, argv, fileno (infp), -1, -1, &pid)) result = 1; /* Execute error - assume password should no be used. */ else if (gnupg_wait_process (pgmname, pid, 1, NULL)) result = 1; /* Helper returned an error - probably a match. */ else result = 0; /* Success; i.e. no match. */ gnupg_release_process (pid); /* Overwrite our temporary file. */ fseek (infp, 0, SEEK_SET); clearerr (infp); for (i=((strlen (pw)+99)/100)*100; i > 0; i--) putc ('\xff', infp); fflush (infp); fclose (infp); + + xfree (patternfname); return result; } static int take_this_one_anyway (ctrl_t ctrl, const char *desc, const char *anyway_btn) { return agent_get_confirmation (ctrl, desc, anyway_btn, L_("Enter new passphrase"), 0); } /* Check whether the passphrase PW is suitable. Returns 0 if the * passphrase is suitable and true if it is not and the user should be * asked to provide a different one. If FAILED_CONSTRAINT is set, a * message describing the problem is returned at FAILED_CONSTRAINT. * The FLAGS are: * CHECK_CONSTRAINTS_NOT_EMPTY * Do not allow an empty passphrase * CHECK_CONSTRAINTS_NEW_SYMKEY * Hint that the passphrase is used for a new symmetric key. */ int check_passphrase_constraints (ctrl_t ctrl, const char *pw, unsigned int flags, char **failed_constraint) { gpg_error_t err = 0; unsigned int minlen = opt.min_passphrase_len; unsigned int minnonalpha = opt.min_passphrase_nonalpha; char *msg1 = NULL; char *msg2 = NULL; char *msg3 = NULL; int no_empty = !!(flags & CHECK_CONSTRAINTS_NOT_EMPTY); if (ctrl && ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK) return 0; if (!pw) pw = ""; /* The first check is to warn about an empty passphrase. */ if (!*pw) { const char *desc = (opt.enforce_passphrase_constraints || no_empty? L_("You have not entered a passphrase!%0A" "An empty passphrase is not allowed.") : L_("You have not entered a passphrase - " "this is in general a bad idea!%0A" "Please confirm that you do not want to " "have any protection on your key.")); err = 1; if (failed_constraint) { if (opt.enforce_passphrase_constraints || no_empty) *failed_constraint = xstrdup (desc); else err = take_this_one_anyway (ctrl, desc, L_("Yes, protection is not needed")); } goto leave; } /* Now check the constraints and collect the error messages unless in silent mode which returns immediately. */ if (utf8_charcount (pw, -1) < minlen ) { if (!failed_constraint) { err = gpg_error (GPG_ERR_INV_PASSPHRASE); goto leave; } msg1 = xtryasprintf ( ngettext ("A passphrase should be at least %u character long.", "A passphrase should be at least %u characters long.", minlen), minlen ); if (!msg1) { err = gpg_error_from_syserror (); goto leave; } } if (nonalpha_count (pw) < minnonalpha ) { if (!failed_constraint) { err = gpg_error (GPG_ERR_INV_PASSPHRASE); goto leave; } msg2 = xtryasprintf ( ngettext ("A passphrase should contain at least %u digit or%%0A" "special character.", "A passphrase should contain at least %u digits or%%0A" "special characters.", minnonalpha), minnonalpha ); if (!msg2) { err = gpg_error_from_syserror (); goto leave; } } /* If configured check the passphrase against a list of known words and pattern. The actual test is done by an external program. The warning message is generic to give the user no hint on how to circumvent this list. */ if (*pw && (opt.check_passphrase_pattern || opt.check_sym_passphrase_pattern) && do_check_passphrase_pattern (ctrl, pw, flags)) { if (!failed_constraint) { err = gpg_error (GPG_ERR_INV_PASSPHRASE); goto leave; } msg3 = xtryasprintf (L_("A passphrase may not be a known term or match%%0A" "certain pattern.")); if (!msg3) { err = gpg_error_from_syserror (); goto leave; } } if (failed_constraint && (msg1 || msg2 || msg3)) { char *msg; size_t n; msg = strconcat (L_("Warning: You have entered an insecure passphrase."), "%0A%0A", msg1? msg1 : "", msg1? "%0A" : "", msg2? msg2 : "", msg2? "%0A" : "", msg3? msg3 : "", msg3? "%0A" : "", NULL); if (!msg) { err = gpg_error_from_syserror (); goto leave; } /* Strip a trailing "%0A". */ n = strlen (msg); if (n > 3 && !strcmp (msg + n - 3, "%0A")) msg[n-3] = 0; err = 1; if (opt.enforce_passphrase_constraints) *failed_constraint = msg; else { err = take_this_one_anyway (ctrl, msg, L_("Take this one anyway")); xfree (msg); } } leave: xfree (msg1); xfree (msg2); xfree (msg3); return err; } /* Callback function to compare the first entered PIN with the one currently being entered. */ static gpg_error_t reenter_compare_cb (struct pin_entry_info_s *pi) { const char *pin1 = pi->check_cb_arg; if (!strcmp (pin1, pi->pin)) return 0; /* okay */ return gpg_error (GPG_ERR_BAD_PASSPHRASE); } /* Ask the user for a new passphrase using PROMPT. On success the function returns 0 and store the passphrase at R_PASSPHRASE; if the user opted not to use a passphrase NULL will be stored there. The user needs to free the returned string. In case of an error and error code is returned and NULL stored at R_PASSPHRASE. */ gpg_error_t agent_ask_new_passphrase (ctrl_t ctrl, const char *prompt, char **r_passphrase) { gpg_error_t err; const char *text1 = prompt; const char *text2 = L_("Please re-enter this passphrase"); char *initial_errtext = NULL; struct pin_entry_info_s *pi, *pi2; *r_passphrase = NULL; if (ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK) { size_t size; unsigned char *buffer; err = pinentry_loopback (ctrl, "NEW_PASSPHRASE", &buffer, &size, MAX_PASSPHRASE_LEN); if (!err) { if (size) { buffer[size] = 0; *r_passphrase = buffer; } else *r_passphrase = NULL; } return err; } pi = gcry_calloc_secure (1, sizeof (*pi) + MAX_PASSPHRASE_LEN + 1); if (!pi) return gpg_error_from_syserror (); pi2 = gcry_calloc_secure (1, sizeof (*pi2) + MAX_PASSPHRASE_LEN + 1); if (!pi2) { err = gpg_error_from_syserror (); xfree (pi); return err; } pi->max_length = MAX_PASSPHRASE_LEN + 1; pi->max_tries = 3; pi->with_qualitybar = 0; pi->with_repeat = 1; pi2->max_length = MAX_PASSPHRASE_LEN + 1; pi2->max_tries = 3; pi2->check_cb = reenter_compare_cb; pi2->check_cb_arg = pi->pin; next_try: err = agent_askpin (ctrl, text1, NULL, initial_errtext, pi, NULL, 0); xfree (initial_errtext); initial_errtext = NULL; if (!err) { if (check_passphrase_constraints (ctrl, pi->pin, 0, &initial_errtext)) { pi->failed_tries = 0; pi2->failed_tries = 0; goto next_try; } /* Unless the passphrase is empty or the pinentry told us that it already did the repetition check, ask to confirm it. */ if (*pi->pin && !pi->repeat_okay) { err = agent_askpin (ctrl, text2, NULL, NULL, pi2, NULL, 0); if (gpg_err_code (err) == GPG_ERR_BAD_PASSPHRASE) { /* The re-entered one did not match and the user did not hit cancel. */ initial_errtext = xtrystrdup (L_("does not match - try again")); if (initial_errtext) goto next_try; err = gpg_error_from_syserror (); } } } if (!err && *pi->pin) { /* User wants a passphrase. */ *r_passphrase = xtrystrdup (pi->pin); if (!*r_passphrase) err = gpg_error_from_syserror (); } xfree (initial_errtext); xfree (pi2); xfree (pi); return err; } /* Generate a new keypair according to the parameters given in KEYPARAM. If CACHE_NONCE is given first try to lookup a passphrase using the cache nonce. If NO_PROTECTION is true the key will not be protected by a passphrase. If OVERRIDE_PASSPHRASE is true that passphrase will be used for the new key. If TIMESTAMP is not zero it will be recorded as creation date of the key (unless extended format is disabled) . */ int agent_genkey (ctrl_t ctrl, const char *cache_nonce, time_t timestamp, const char *keyparam, size_t keyparamlen, int no_protection, const char *override_passphrase, int preset, membuf_t *outbuf) { gcry_sexp_t s_keyparam, s_key, s_private, s_public; char *passphrase_buffer = NULL; const char *passphrase; int rc; size_t len; char *buf; rc = gcry_sexp_sscan (&s_keyparam, NULL, keyparam, keyparamlen); if (rc) { log_error ("failed to convert keyparam: %s\n", gpg_strerror (rc)); return gpg_error (GPG_ERR_INV_DATA); } /* Get the passphrase now, cause key generation may take a while. */ if (override_passphrase) passphrase = override_passphrase; else if (no_protection || !cache_nonce) passphrase = NULL; else { passphrase_buffer = agent_get_cache (ctrl, cache_nonce, CACHE_MODE_NONCE); passphrase = passphrase_buffer; } if (passphrase || no_protection) ; else { rc = agent_ask_new_passphrase (ctrl, L_("Please enter the passphrase to%0A" "protect your new key"), &passphrase_buffer); if (rc) { gcry_sexp_release (s_keyparam); return rc; } passphrase = passphrase_buffer; } rc = gcry_pk_genkey (&s_key, s_keyparam ); gcry_sexp_release (s_keyparam); if (rc) { log_error ("key generation failed: %s\n", gpg_strerror (rc)); xfree (passphrase_buffer); return rc; } /* break out the parts */ s_private = gcry_sexp_find_token (s_key, "private-key", 0); if (!s_private) { log_error ("key generation failed: invalid return value\n"); gcry_sexp_release (s_key); xfree (passphrase_buffer); return gpg_error (GPG_ERR_INV_DATA); } s_public = gcry_sexp_find_token (s_key, "public-key", 0); if (!s_public) { log_error ("key generation failed: invalid return value\n"); gcry_sexp_release (s_private); gcry_sexp_release (s_key); xfree (passphrase_buffer); return gpg_error (GPG_ERR_INV_DATA); } gcry_sexp_release (s_key); s_key = NULL; /* store the secret key */ if (DBG_CRYPTO) log_debug ("storing private key\n"); rc = store_key (s_private, passphrase, 0, ctrl->s2k_count, timestamp); if (!rc) { if (!cache_nonce) { char tmpbuf[12]; gcry_create_nonce (tmpbuf, 12); cache_nonce = bin2hex (tmpbuf, 12, NULL); } if (cache_nonce && !no_protection && !agent_put_cache (ctrl, cache_nonce, CACHE_MODE_NONCE, passphrase, ctrl->cache_ttl_opt_preset)) agent_write_status (ctrl, "CACHE_NONCE", cache_nonce, NULL); if (preset && !no_protection) { unsigned char grip[20]; char hexgrip[40+1]; if (gcry_pk_get_keygrip (s_private, grip)) { bin2hex(grip, 20, hexgrip); rc = agent_put_cache (ctrl, hexgrip, CACHE_MODE_ANY, passphrase, ctrl->cache_ttl_opt_preset); } } } xfree (passphrase_buffer); passphrase_buffer = NULL; passphrase = NULL; gcry_sexp_release (s_private); if (rc) { gcry_sexp_release (s_public); return rc; } /* return the public key */ if (DBG_CRYPTO) log_debug ("returning public key\n"); len = gcry_sexp_sprint (s_public, GCRYSEXP_FMT_CANON, NULL, 0); log_assert (len); buf = xtrymalloc (len); if (!buf) { gpg_error_t tmperr = out_of_core (); gcry_sexp_release (s_private); gcry_sexp_release (s_public); return tmperr; } len = gcry_sexp_sprint (s_public, GCRYSEXP_FMT_CANON, buf, len); log_assert (len); put_membuf (outbuf, buf, len); gcry_sexp_release (s_public); xfree (buf); return 0; } /* Apply a new passphrase to the key S_SKEY and store it. If PASSPHRASE_ADDR and *PASSPHRASE_ADDR are not NULL, use that passphrase. If PASSPHRASE_ADDR is not NULL store a newly entered passphrase at that address. */ gpg_error_t agent_protect_and_store (ctrl_t ctrl, gcry_sexp_t s_skey, char **passphrase_addr) { gpg_error_t err; if (passphrase_addr && *passphrase_addr) { /* Take an empty string as request not to protect the key. */ err = store_key (s_skey, **passphrase_addr? *passphrase_addr:NULL, 1, ctrl->s2k_count, 0); } else { char *pass = NULL; if (passphrase_addr) { xfree (*passphrase_addr); *passphrase_addr = NULL; } err = agent_ask_new_passphrase (ctrl, L_("Please enter the new passphrase"), &pass); if (!err) err = store_key (s_skey, pass, 1, ctrl->s2k_count, 0); if (!err && passphrase_addr) *passphrase_addr = pass; else xfree (pass); } return err; } diff --git a/doc/gpg-agent.texi b/doc/gpg-agent.texi index b50767060..f20d83384 100644 --- a/doc/gpg-agent.texi +++ b/doc/gpg-agent.texi @@ -1,1624 +1,1626 @@ @c Copyright (C) 2002 Free Software Foundation, Inc. @c This is part of the GnuPG manual. @c For copying conditions, see the file gnupg.texi. @include defs.inc @node Invoking GPG-AGENT @chapter Invoking GPG-AGENT @cindex GPG-AGENT command options @cindex command options @cindex options, GPG-AGENT command @manpage gpg-agent.1 @ifset manverb .B gpg-agent \- Secret key management for GnuPG @end ifset @mansect synopsis @ifset manverb .B gpg-agent .RB [ \-\-homedir .IR dir ] .RB [ \-\-options .IR file ] .RI [ options ] .br .B gpg-agent .RB [ \-\-homedir .IR dir ] .RB [ \-\-options .IR file ] .RI [ options ] .B \-\-server .br .B gpg-agent .RB [ \-\-homedir .IR dir ] .RB [ \-\-options .IR file ] .RI [ options ] .B \-\-daemon .RI [ command_line ] @end ifset @mansect description @command{gpg-agent} is a daemon to manage secret (private) keys independently from any protocol. It is used as a backend for @command{gpg} and @command{gpgsm} as well as for a couple of other utilities. 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: @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 controlled and audited, and it doesn't permit @c the supplicant to either copy the key or to override the owner's @c intentions. @example gpg-connect-agent /bye @end example @noindent If you want to manually terminate the currently-running agent, you can safely do so with: @example gpgconf --kill gpg-agent @end example @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: @smallexample GPG_TTY=$(tty) export GPG_TTY @end smallexample @noindent It is important that this environment variable always reflects the output of the @code{tty} command. For W32 systems this option is not required. Please make sure that a proper pinentry program has been installed 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{@value{BINDIR}/pinentry-gtk}) to the expected one (e.g. @file{@value{BINDIR}/pinentry}). @manpause @noindent @xref{Option Index}, for an index to @command{GPG-AGENT}'s commands and options. @mancont @menu * Agent Commands:: List of all commands. * Agent Options:: List of all options. * Agent Configuration:: Configuration files. * Agent Signals:: Use of some signals. * Agent Examples:: Some usage examples. * Agent Protocol:: The protocol the agent uses. @end menu @mansect commands @node Agent Commands @section Commands Commands are not distinguished from options except for the fact that only one command is allowed. @table @gnupgtabopt @item --version @opindex version Print the program version and licensing information. Note that you cannot abbreviate this command. @item --help @itemx -h @opindex help Print a usage message summarizing the most useful command-line options. Note that you cannot abbreviate this command. @item --dump-options @opindex dump-options Print a list of all available options and commands. Note that you cannot abbreviate this command. @item --server @opindex server Run in server mode and wait for commands on the @code{stdin}. The default mode is to create a socket and listen for commands there. @item --daemon [@var{command line}] @opindex daemon Start the gpg-agent as a daemon; that is, detach it from the console and run it in the background. 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. @item --supervised @opindex supervised Run in the foreground, sending logs by default to stderr, and listening on provided file descriptors, which must already be bound to listening sockets. This command is useful when running under systemd or other similar process supervision schemes. This option is not supported on Windows. In --supervised mode, different file descriptors can be provided for use as different socket types (e.g. ssh, extra) as long as they are identified in the environment variable @code{LISTEN_FDNAMES} (see sd_listen_fds(3) on some Linux distributions for more information on this convention). @end table @mansect options @node Agent Options @section Option Summary Options may either be used on the command line or, after stripping off the two leading dashes, in the configuration file. @table @gnupgtabopt @anchor{option --options} @item --options @var{file} @opindex options Reads configuration from @var{file} instead of from the default per-user configuration file. The default configuration file is named @file{gpg-agent.conf} and expected in the @file{.gnupg} directory directly below the home directory of the user. This option is ignored if used in an options file. @anchor{option --homedir} @include opt-homedir.texi @item -v @itemx --verbose @opindex verbose Outputs additional information while running. You can increase the verbosity by giving several verbose commands to @command{gpg-agent}, such as @samp{-vv}. @item -q @itemx --quiet @opindex quiet Try to be as quiet as possible. @item --batch @opindex batch Don't invoke a pinentry or do any other thing requiring human interaction. @item --faked-system-time @var{epoch} @opindex faked-system-time This option is only useful for testing; it sets the system time back or forth to @var{epoch} which is the number of seconds elapsed since the year 1970. @item --debug-level @var{level} @opindex debug-level Select the debug level for investigating problems. @var{level} may be a numeric value or a keyword: @table @code @item none No debugging at all. A value of less than 1 may be used instead of the keyword. @item basic Some basic debug messages. A value between 1 and 2 may be used instead of the keyword. @item advanced More verbose debug messages. A value between 3 and 5 may be used instead of the keyword. @item expert Even more detailed messages. A value between 6 and 8 may be used instead of the keyword. @item guru All of the debug messages you can get. A value greater than 8 may be used instead of the keyword. The creation of hash tracing files is only enabled if the keyword is used. @end table How these messages are mapped to the actual debugging flags is not specified and may change with newer releases of this program. They are however carefully selected to best aid in debugging. @item --debug @var{flags} @opindex debug Set debug flags. All flags are or-ed and @var{flags} may be given in C syntax (e.g. 0x0042) or as a comma separated list of flag names. To get a list of all supported flags the single word "help" can be used. This option is only useful for debugging and the behavior may change at any time without notice. @item --debug-all @opindex debug-all Same as @code{--debug=0xffffffff} @item --debug-wait @var{n} @opindex debug-wait When running in server mode, wait @var{n} seconds before entering the actual processing loop and print the pid. This gives time to attach a debugger. @item --debug-quick-random @opindex debug-quick-random 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 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 Pinentry. As of now it is only useful when used along with @code{--debug 1024}. @item --no-detach @opindex no-detach Don't detach the process from the console. This is mainly useful for debugging. @item -s @itemx --sh @itemx -c @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. @item --grab @itemx --no-grab @opindex grab @opindex no-grab Tell the pinentry to grab the keyboard and mouse. This option should be used on X-Servers to avoid X-sniffing attacks. Any use of the option @option{--grab} overrides an used option @option{--no-grab}. The default is @option{--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. Use @file{socket://} to log to socket. If neither a log file nor a log file descriptor has been set on a Windows platform, the Registry entry @code{HKCU\Software\GNU\GnuPG:DefaultLogFile}, if set, is used to specify the logging output. @anchor{option --no-allow-mark-trusted} @item --no-allow-mark-trusted @opindex no-allow-mark-trusted Do not allow clients to mark keys as trusted, i.e. put them into the @file{trustlist.txt} file. This makes it harder for users to inadvertently accept Root-CA keys. @anchor{option --allow-preset-passphrase} @item --allow-preset-passphrase @opindex allow-preset-passphrase This option allows the use of @command{gpg-preset-passphrase} to seed the internal cache of @command{gpg-agent} with passphrases. @anchor{option --no-allow-loopback-pinentry} @item --no-allow-loopback-pinentry @item --allow-loopback-pinentry @opindex no-allow-loopback-pinentry @opindex allow-loopback-pinentry 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. @item --no-allow-external-cache @opindex no-allow-external-cache Tell Pinentry not to enable features which use an external cache for passphrases. Some desktop environments prefer to unlock all credentials with one master password and may have installed a Pinentry 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. @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 This option will let @command{gpg-agent} bypass the passphrase cache for all signing operation. Note that there is also a per-session option to control this behavior but this command line option takes precedence. @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. 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}. Note that a cached passphrase may not be evicted immediately from memory if no client requests a cache operation. This is due to an internal housekeeping function which is only run every few seconds. @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. 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 Set the maximum time a cache entry is valid to @var{n} seconds. After this time a cache entry will be expired even if it has been accessed recently or has been set using @command{gpg-preset-passphrase}. The default is 2 hours (7200 seconds). @item --max-cache-ttl-ssh @var{n} @opindex max-cache-ttl-ssh Set the maximum time a cache entry used for SSH keys is valid to @var{n} seconds. After this time a cache entry will be expired even if it has been accessed recently or has been set using @command{gpg-preset-passphrase}. The default is 2 hours (7200 seconds). @item --enforce-passphrase-constraints @opindex enforce-passphrase-constraints Enforce the passphrase constraints by not allowing the user to bypass them using the ``Take it anyway'' button. @item --min-passphrase-len @var{n} @opindex min-passphrase-len Set the minimal length of a passphrase. When entering a new passphrase shorter than this value a warning will be displayed. Defaults to 8. @item --min-passphrase-nonalpha @var{n} @opindex min-passphrase-nonalpha Set the minimal number of digits or special characters required in a passphrase. When entering a new passphrase with less than this number of digits or special characters a warning will be displayed. Defaults to 1. @item --check-passphrase-pattern @var{file} @itemx --check-sym-passphrase-pattern @var{file} @opindex check-passphrase-pattern @opindex check-sym-passphrase-pattern Check the passphrase against the pattern given in @var{file}. When entering a new passphrase matching one of these pattern a warning will -be displayed. @var{file} should be an absolute filename. The default -is not to use any pattern file. The second version of this option is -only used when creating a new symmetric key to allow the use of -different patterns for such passphrases. +be displayed. If @var{file} does not contain any slashes and does not +start with "~/" it is searched in the system configuration directory +(@file{@value{SYSCONFDIR}}). The default is not to use any +pattern file. The second version of this option is only used when +creating a new symmetric key to allow the use of different patterns +for such passphrases. Security note: It is known that checking a passphrase against a list of pattern or even against a complete dictionary is not very effective to enforce good passphrases. Users will soon figure up ways to bypass such a policy. A better policy is to educate users on good security behavior and optionally to run a passphrase cracker regularly on all users passphrases to catch the very simple ones. @item --max-passphrase-days @var{n} @opindex max-passphrase-days Ask the user to change the passphrase if @var{n} days have passed since the last change. With @option{--enforce-passphrase-constraints} set the user may not bypass this check. @item --enable-passphrase-history @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-formatted-passphrase @opindex pinentry-formatted-passphrase This option asks the Pinentry to enable passphrase formatting when asking the user for a new passphrase and masking of the passphrase is turned off. If passphrase formatting is enabled, then all non-breaking space characters are stripped from the entered passphrase. Passphrase formatting is mostly useful in combination with passphrases generated with the GENPIN feature of some Pinentries. Note that such a generated passphrase, if not modified by the user, skips all passphrase constraints checking because such constraints would actually weaken the generated passphrase. @item --pinentry-program @var{filename} @opindex pinentry-program Use program @var{filename} as the PIN entry. The default is installation dependent. With the default configuration the name of 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 requests is passed to Pinentry, so that it can touch that file before exiting (it does this only in curses mode). This option changes the file passed to Pinentry to @var{filename}. The special name @code{/dev/null} may be used to completely disable this feature. Note that Pinentry will not create that file, it will only change the modification and access time. @item --scdaemon-program @var{filename} @opindex scdaemon-program Use program @var{filename} as the Smartcard daemon. The default is installation dependent and can be shown with the @command{gpgconf} command. @item --disable-scdaemon @opindex disable-scdaemon Do not make use of the scdaemon tool. This option has the effect of disabling the ability to do smartcard operations. Note, that enabling this option at runtime does not kill an already forked scdaemon. @item --disable-check-own-socket @opindex disable-check-own-socket @command{gpg-agent} employs a periodic self-test to detect a stolen socket. This usually means a second instance of @command{gpg-agent} 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. @item --use-standard-socket @itemx --no-use-standard-socket @itemx --use-standard-socket-p @opindex use-standard-socket @opindex no-use-standard-socket @opindex use-standard-socket-p 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. @item --display @var{string} @itemx --ttyname @var{string} @itemx --ttytype @var{string} @itemx --lc-ctype @var{string} @itemx --lc-messages @var{string} @itemx --xauthority @var{string} @opindex display @opindex ttyname @opindex ttytype @opindex lc-ctype @opindex lc-messages @opindex xauthority These options are used with the server mode to pass localization information. @item --keep-tty @itemx --keep-display @opindex keep-tty @opindex keep-display Ignore requests to change the current @code{tty} or X window system's @code{DISPLAY} variable respectively. This is useful to lock the pinentry to pop up at the @code{tty} or display you started the agent. @item --listen-backlog @var{n} @opindex listen-backlog Set the size of the queue for pending connections. The default is 64. @anchor{option --extra-socket} @item --extra-socket @var{name} @opindex extra-socket The extra socket is created by default, you may use this option to change the name of the socket. To disable the creation of the socket use ``none'' or ``/dev/null'' for @var{name}. Also listen on native gpg-agent connections on the given socket. The intended use for this extra socket is to setup a Unix domain socket forwarding from a remote machine to this socket on the local machine. A @command{gpg} running on the remote machine may then connect to the local gpg-agent and use its private keys. This enables decrypting or signing data on a remote machine without exposing the private keys to the remote machine. @item --enable-extended-key-format @itemx --disable-extended-key-format @opindex enable-extended-key-format @opindex disable-extended-key-format Since version 2.3 keys are created in the extended private key format. Changing the passphrase of a key will also convert the key to that new format. This new key format is supported since GnuPG version 2.1.12 and thus there should be no need to disable it. The disable option allows to revert to the old behavior for new keys; be aware that keys are never migrated back to the old format. However if the enable option has been used the disable option won't have an effect. The advantage of the extended private key format is that it is text based and can carry additional meta data. @anchor{option --enable-ssh-support} @item --enable-ssh-support @itemx --enable-putty-support @opindex enable-ssh-support @opindex enable-putty-support The OpenSSH Agent protocol is always enabled, but @command{gpg-agent} will only set the @code{SSH_AUTH_SOCK} variable if this flag is given. In this mode of operation, the agent does not only implement the gpg-agent protocol, but also the agent protocol used by OpenSSH (through a separate socket). Consequently, it should be possible to use the gpg-agent as a drop-in replacement for the well known ssh-agent. SSH Keys, which are to be used through the agent, need to be added to the gpg-agent initially through the ssh-add utility. When a key is added, ssh-add will ask for the password of the provided key file and send the unprotected key material to the agent; this causes the gpg-agent to ask for a passphrase, which is to be used for encrypting the newly received key and storing it in a gpg-agent specific directory. Once a key has been added to the gpg-agent this way, the gpg-agent will be ready to use the key. Note: in case the gpg-agent receives a signature request, the user might need to be prompted for a passphrase, which is necessary for decrypting the stored key. Since the ssh-agent protocol does not contain a mechanism for telling the agent on which display/terminal it is running, gpg-agent's ssh-support will use the TTY or X display where gpg-agent has been started. To switch this display to the current one, the following command may be used: @smallexample gpg-connect-agent updatestartuptty /bye @end smallexample Although all GnuPG components try to start the gpg-agent as needed, this is not possible for the ssh support because ssh does not know about it. Thus if no GnuPG tool which accesses the agent has been run, there is no guarantee that ssh is able to use gpg-agent for authentication. To fix this you may start gpg-agent if needed using this simple command: @smallexample gpg-connect-agent /bye @end smallexample 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}. @anchor{option --ssh-fingerprint-digest} @item --ssh-fingerprint-digest @opindex ssh-fingerprint-digest Select the digest algorithm used to compute ssh fingerprints that are communicated to the user, e.g. in pinentry dialogs. OpenSSH has transitioned from using MD5 to the more secure SHA256. @item --auto-expand-secmem @var{n} @opindex auto-expand-secmem Allow Libgcrypt to expand its secure memory area as required. The optional value @var{n} is a non-negative integer with a suggested size in bytes of each additionally allocated secure memory area. The value is rounded up to the next 32 KiB; usual C style prefixes are allowed. For an heavy loaded gpg-agent with many concurrent connection this option avoids sign or decrypt errors due to out of secure memory error returns. @item --s2k-calibration @var{milliseconds} @opindex s2k-calibration Change the default calibration time to @var{milliseconds}. The given value is capped at 60 seconds; a value of 0 resets to the compiled-in default. This option is re-read on a SIGHUP (or @code{gpgconf --reload gpg-agent}) and the S2K count is then re-calibrated. @item --s2k-count @var{n} @opindex s2k-count Specify the iteration count used to protect the passphrase. This option can be used to override the auto-calibration done by default. The auto-calibration computes a count which requires by default 100ms to mangle a given passphrase. See also @option{--s2k-calibration}. To view the actually used iteration count and the milliseconds required for an S2K operation use: @example gpg-connect-agent 'GETINFO s2k_count' /bye gpg-connect-agent 'GETINFO s2k_time' /bye @end example To view the auto-calibrated count use: @example gpg-connect-agent 'GETINFO s2k_count_cal' /bye @end example @end table @mansect files @node Agent Configuration @section Configuration There are a few configuration files needed for the operation of the agent. By default they may all be found in the current home directory (@pxref{option --homedir}). @table @file @item 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. This file is also read after a @code{SIGHUP} however only a few options will actually have an effect. This default name may be changed on the command line (@pxref{option --options}). 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 lines are ignored. To mark a key as trusted you need to enter its fingerprint followed by a space and a capital letter @code{S}. Colons may optionally be used to separate the bytes of a fingerprint; this enables cutting and pasting the fingerprint from a key listing output. If the line is prefixed with a @code{!} the key is explicitly marked as not trusted. Here is an example where two keys are marked as ultimately trusted and one as not trusted: @cartouche @smallexample # CN=Wurzel ZS 3,O=Intevation GmbH,C=DE A6935DD34EF3087973C706FC311AA2CCF733765B S # CN=PCA-1-Verwaltung-02/O=PKI-1-Verwaltung/C=DE DC:BD:69:25:48:BD:BB:7E:31:6E:BB:80:D3:00:80:35:D4:F8:A6:CD S # CN=Root-CA/O=Schlapphuete/L=Pullach/C=DE !14:56:98:D3:FE:9C:CA:5A:31:6E:BC:81:D3:11:4E:00:90:A3:44:C2 S @end smallexample @end cartouche Before entering a key into this file, you need to ensure its authenticity. How to do this depends on your organisation; your administrator might have already entered those keys which are deemed trustworthy enough into this file. Places where to look for the fingerprint of a root certificate are letters received from the CA or the website of the CA (after making 100% sure that this is indeed the website of that CA). You may want to consider disallowing interactive updates of this file by using the @ref{option --no-allow-mark-trusted}. It might even be advisable to change the permissions to read-only so 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{@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 caller: @table @code @item relax @cindex relax Relax checking of some root certificate requirements. As of now this flag allows the use of root certificates with a missing basicConstraints attribute (despite that it is a MUST for CA certificates) and disables CRL checking for the root certificate. @item cm If validation of a certificate finally issued by a CA with this flag set fails, try again using the chain validation model. @end table @item 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. The @command{ssh-add} tool may be used to add new entries to this file; you may also add them manually. Comment lines, indicated by a leading hash mark, as well as empty lines are ignored. An entry starts with optional whitespace, followed by the keygrip of the key given as 40 hex digits, optionally followed by the caching TTL in seconds and another optional field for arbitrary flags. A non-zero TTL overrides the global default as set by @option{--default-cache-ttl-ssh}. The only flag support is @code{confirm}. If this flag is found for a key, each use of the key will pop up a pinentry to confirm the use of that key. The flag is automatically set if a new key was loaded into @code{gpg-agent} using the option @option{-c} of the @code{ssh-add} command. The keygrip may be prefixed with a @code{!} to disable an entry. The following example lists exactly one key. Note that keys available through a OpenPGP smartcard in the active smartcard reader are implicitly added to this list; i.e. there is no need to list them. @cartouche @smallexample # Key added on: 2011-07-20 20:38:46 # Fingerprint: 5e:8d:c4:ad:e7:af:6e:27:8a:d6:13:e4:79:ad:0b:81 34B62F25E277CF13D3C6BCEBFD3F85D08F0A864B 0 confirm @end smallexample @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 suffix @file{key}. You should backup all files in this directory and take great care to keep this backup closed away. @end table Note that on larger installations, it is useful to put predefined 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}). @c @c Agent Signals @c @mansect signals @node Agent Signals @section Use of some signals A running @command{gpg-agent} may be controlled by signals, i.e. using the @command{kill} command to send a signal to the process. Here is a list of supported signals: @table @gnupgtabopt @item SIGHUP @cpindex SIGHUP This signal flushes all cached passphrases and if the program has been started with a configuration file, the configuration file is read 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{pinentry-invisible-char}, @code{default-cache-ttl}, @code{max-cache-ttl}, @code{ignore-cache-for-signing}, @code{s2k-count}, @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 scdaemon only once, it is not of much use unless you manually kill the scdaemon. @item SIGTERM @cpindex SIGTERM Shuts down the process but waits until all current requests are fulfilled. If the process has received 3 of these signals and requests are still pending, a shutdown is forced. @item SIGINT @cpindex SIGINT Shuts down the process immediately. @item SIGUSR1 @cpindex SIGUSR1 Dump internal information to the log file. @item SIGUSR2 @cpindex SIGUSR2 This signal is used for internal purposes. @end table @c @c Examples @c @mansect examples @node Agent Examples @section Examples 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 export GPG_TTY=$(tty) @end example @end cartouche If you enabled the Ssh Agent Support, you also need to tell ssh about it by adding this to your init script: @cartouche @example unset SSH_AGENT_PID if [ "$@{gnupg_SSH_AUTH_SOCK_by:-0@}" -ne $$ ]; then export SSH_AUTH_SOCK="$(gpgconf --list-dirs agent-ssh-socket)" fi @end example @end cartouche @c @c Assuan Protocol @c @manpause @node Agent 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. To see the full specification of each command, use @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. 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 Libgcrypt. For the purpose of this interface the keygrip is given as a hex string. The advantage of using this and not the hash of a certificate is that it will be possible to use the same keypair for different protocols, thereby saving space on the token used to keep the secret keys. 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). @menu * Agent PKDECRYPT:: Decrypting a session key * Agent PKSIGN:: Signing a Hash * Agent GENKEY:: Generating a Key * Agent IMPORT:: Importing a Secret Key * Agent EXPORT:: Exporting a Secret Key * Agent ISTRUSTED:: Importing a Root Certificate * Agent GET_PASSPHRASE:: Ask for a passphrase * Agent CLEAR_PASSPHRASE:: Expire a cached passphrase * Agent PRESET_PASSPHRASE:: Set a passphrase for a keygrip * Agent GET_CONFIRMATION:: Ask for confirmation * Agent HAVEKEY:: Check whether a key is available * Agent LEARN:: Register a smartcard * Agent PASSWD:: Change a Passphrase * Agent UPDATESTARTUPTTY:: Change the Standard Display * Agent GETEVENTCOUNTER:: Get the Event Counters * Agent GETINFO:: Return information about the process * Agent OPTION:: Set options for the session @end menu @node Agent PKDECRYPT @subsection Decrypting a session key The client asks the server to decrypt a session key. The encrypted session key should have all information needed to select the appropriate secret key or to delegate it to a smartcard. @example SETKEY @end example Tell the server about the key to be used for decryption. If this is not used, @command{gpg-agent} may try to figure out the key by trying to decrypt the message with each key available. @example PKDECRYPT @end example The agent checks whether this command is allowed and then does an INQUIRY to get the ciphertext the client should then send the cipher text. @example S: INQUIRE CIPHERTEXT C: D (xxxxxx C: D xxxx) C: END @end example Please note that the server may send status info lines while reading the data lines from the client. The data send is a SPKI like S-Exp with this structure: @example (enc-val ( ( ) ... ( ))) @end example Where algo is a string with the name of the algorithm; see the libgcrypt documentation for a list of valid algorithms. The number and names of the parameters depend on the algorithm. The agent does return an error if there is an inconsistency. If the decryption was successful the decrypted data is returned by means of "D" lines. Here is an example session: @cartouche @smallexample C: PKDECRYPT S: INQUIRE CIPHERTEXT C: D (enc-val elg (a 349324324) C: D (b 3F444677CA))) C: END S: # session key follows S: S PADDING 0 S: D (value 1234567890ABCDEF0) S: OK decryption successful @end smallexample @end cartouche The “PADDING” status line is only send if gpg-agent can tell what kind of padding is used. As of now only the value 0 is used to indicate that the padding has been removed. @node Agent PKSIGN @subsection Signing a Hash The client asks the agent to sign a given hash value. A default key will be chosen if no key has been set. To set a key a client first uses: @example SIGKEY @end example This can be used multiple times to create multiple signature, the list of keys is reset with the next PKSIGN command or a RESET. The server tests whether the key is a valid key to sign something and responds with okay. @example SETHASH --hash=| @end example The client can use this command to tell the server about the data (which usually is a hash) to be signed. is the decimal encoded hash algorithm number as used by Libgcrypt. Either or --hash= must be given. Valid names for are: @table @code @item sha1 The SHA-1 hash algorithm @item sha256 The SHA-256 hash algorithm @item rmd160 The RIPE-MD160 hash algorithm @item md5 The old and broken MD5 hash algorithm @item tls-md5sha1 A combined hash algorithm as used by the TLS protocol. @end table @noindent The actual signing is done using @example PKSIGN @end example Options are not yet defined, but may later be used to choose among different algorithms. The agent does then some checks, asks for the passphrase and as a result the server returns the signature as an SPKI like S-expression in "D" lines: @example (sig-val ( ( ) ... ( ))) @end example The operation is affected by the option @example OPTION use-cache-for-signing=0|1 @end example The default of @code{1} uses the cache. Setting this option to @code{0} will lead @command{gpg-agent} to ignore the passphrase cache. Note, that there is also a global command line option for @command{gpg-agent} to globally disable the caching. Here is an example session: @cartouche @smallexample C: SIGKEY S: OK key available C: SIGKEY S: OK key available C: PKSIGN S: # I did ask the user whether he really wants to sign S: # I did ask the user for the passphrase S: INQUIRE HASHVAL C: D ABCDEF012345678901234 C: END S: # signature follows S: D (sig-val rsa (s 45435453654612121212)) S: OK @end smallexample @end cartouche @node Agent GENKEY @subsection Generating a Key This is used to create a new keypair and store the secret key inside the active PSE --- which is in most cases a Soft-PSE. A not-yet-defined option allows choosing the storage location. To get the secret key out of the PSE, a special export tool has to be used. @example GENKEY [--no-protection] [--preset] [] @end example Invokes the key generation process and the server will then inquire on the generation parameters, like: @example S: INQUIRE KEYPARM C: D (genkey (rsa (nbits 1024))) C: END @end example The format of the key parameters which depends on the algorithm is of the form: @example (genkey (algo (parameter_name_1 ....) .... (parameter_name_n ....))) @end example If everything succeeds, the server returns the *public key* in a SPKI like S-Expression like this: @example (public-key (rsa (n ) (e ))) @end example Here is an example session: @cartouche @smallexample C: GENKEY S: INQUIRE KEYPARM C: D (genkey (rsa (nbits 1024))) C: END S: D (public-key S: D (rsa (n 326487324683264) (e 10001))) S OK key created @end smallexample @end cartouche 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 using the default cache parameters. The @option{--inq-passwd} option may be used to create the key with a supplied passphrase. When used the agent does an inquiry with the keyword @code{NEWPASSWD} to retrieve that passphrase. This option takes precedence over @option{--no-protection}; however if the client sends a empty (zero-length) passphrase, this is identical to @option{--no-protection}. @node Agent IMPORT @subsection Importing a Secret Key This operation is not yet supported by GpgAgent. Specialized tools are to be used for this. There is no actual need because we can expect that secret keys created by a 3rd party are stored on a smartcard. If we have generated the key ourselves, we do not need to import it. @node Agent EXPORT @subsection Export a Secret Key Not implemented. Should be done by an extra tool. @node Agent ISTRUSTED @subsection Importing a Root Certificate Actually we do not import a Root Cert but provide a way to validate any piece of data by storing its Hash along with a description and an identifier in the PSE. Here is the interface description: @example ISTRUSTED @end example Check whether the OpenPGP primary key or the X.509 certificate with the given fingerprint is an ultimately trusted key or a trusted Root CA certificate. The fingerprint should be given as a hexstring (without any blanks or colons or whatever in between) and may be left padded with 00 in case of an MD5 fingerprint. GPGAgent will answer with: @example OK @end example The key is in the table of trusted keys. @example ERR 304 (Not Trusted) @end example The key is not in this table. Gpg needs the entire list of trusted keys to maintain the web of trust; the following command is therefore quite helpful: @example LISTTRUSTED @end example GpgAgent returns a list of trusted keys line by line: @example S: D 000000001234454556565656677878AF2F1ECCFF P S: D 340387563485634856435645634856438576457A P S: D FEDC6532453745367FD83474357495743757435D S S: OK @end example The first item on a line is the hexified fingerprint where MD5 fingerprints are @code{00} padded to the left and the second item is a flag to indicate the type of key (so that gpg is able to only take care of PGP keys). P = OpenPGP, S = S/MIME. A client should ignore the rest of the line, so that we can extend the format in the future. Finally a client should be able to mark a key as trusted: @example MARKTRUSTED @var{fingerprint} "P"|"S" @end example The server will then pop up a window to ask the user whether she really trusts this key. For this it will probably ask for a text to be displayed like this: @example S: INQUIRE TRUSTDESC C: D Do you trust the key with the fingerprint @@FPR@@ C: D bla fasel blurb. C: END S: OK @end example Known sequences with the pattern @@foo@@ are replaced according to this table: @table @code @item @@FPR16@@ Format the fingerprint according to gpg rules for a v3 keys. @item @@FPR20@@ Format the fingerprint according to gpg rules for a v4 keys. @item @@FPR@@ Choose an appropriate format to format the fingerprint. @item @@@@ Replaced by a single @code{@@}. @end table @node Agent GET_PASSPHRASE @subsection Ask for a passphrase This function is usually used to ask for a passphrase to be used for 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. @example GET_PASSPHRASE [--data] [--check] [--no-ask] [--repeat[=N]] \ [--qualitybar] @var{cache_id} \ [@var{error_message} @var{prompt} @var{description}] @end example @var{cache_id} is expected to be a string used to identify a cached passphrase. Use a @code{X} to bypass the cache. With no other arguments the agent returns a cached passphrase or an error. By convention either the hexified fingerprint of the key shall be used for @var{cache_id} or an arbitrary string prefixed with the name of the calling application and a colon: Like @code{gpg:somestring}. @var{error_message} is either a single @code{X} for no error message or a string to be shown as an error message like (e.g. "invalid passphrase"). Blanks must be percent escaped or replaced by @code{+}'. @var{prompt} is either a single @code{X} for a default prompt or the text to be shown as the prompt. Blanks must be percent escaped or replaced by @code{+}. @var{description} is a text shown above the entry field. Blanks must be percent escaped or replaced by @code{+}. The agent either returns with an error or with a OK followed by the hex encoded passphrase. Note that the length of the strings is implicitly limited by the maximum length of a command. If the option @option{--data} is used, the passphrase is not returned on the OK line but by regular data lines; this is the preferred method. If the option @option{--check} is used, the standard passphrase constraints checks are applied. A check is not done if the passphrase has been found in the cache. If the option @option{--no-ask} is used and the passphrase is not in the cache the user will not be asked to enter a passphrase but the error code @code{GPG_ERR_NO_DATA} is returned. If the option @option{--qualitybar} is used and a minimum passphrase length has been configured, a visual indication of the entered passphrase quality is shown. @example CLEAR_PASSPHRASE @var{cache_id} @end example may be used to invalidate the cache entry for a passphrase. The function returns with OK even when there is no cached passphrase. @node Agent CLEAR_PASSPHRASE @subsection Remove a cached passphrase Use this command to remove a cached passphrase. @example CLEAR_PASSPHRASE [--mode=normal] @end example The @option{--mode=normal} option can be used to clear a @var{cache_id} that was set by gpg-agent. @node Agent PRESET_PASSPHRASE @subsection Set a passphrase for a keygrip This command adds a passphrase to the cache for the specified @var{keygrip}. @example PRESET_PASSPHRASE [--inquire] [] @end example The passphrase is a hexadecimal string when specified. When not specified, the passphrase will be retrieved from the pinentry module unless the @option{--inquire} option was specified in which case the passphrase will be retrieved from the client. The @var{timeout} parameter keeps the passphrase cached for the specified number of seconds. A value of @code{-1} means infinite while @code{0} means the default (currently only a timeout of -1 is allowed, which means to never expire it). @node Agent GET_CONFIRMATION @subsection Ask for confirmation This command may be used to ask for a simple confirmation by presenting a text and 2 buttons: Okay and Cancel. @example GET_CONFIRMATION @var{description} @end example @var{description}is displayed along with a Okay and Cancel button. Blanks must be percent escaped or replaced by @code{+}. A @code{X} may be used to display confirmation dialog with a default text. The agent either returns with an error or with a OK. Note, that the length of @var{description} is implicitly limited by the maximum length of a command. @node Agent HAVEKEY @subsection Check whether a key is available This can be used to see whether a secret key is available. It does not return any information on whether the key is somehow protected. @example HAVEKEY @var{keygrips} @end example The agent answers either with OK or @code{No_Secret_Key} (208). The caller may want to check for other error codes as well. More than one keygrip may be given. In this case the command returns success if at least one of the keygrips corresponds to an available secret key. @node Agent LEARN @subsection Register a smartcard @example LEARN [--send] @end example This command is used to register a smartcard. With the @option{--send} option given the certificates are sent back. @node Agent PASSWD @subsection Change a Passphrase @example PASSWD [--cache-nonce=] [--passwd-nonce=] [--preset] @var{keygrip} @end example This command is used to interactively change the passphrase of the key 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 @subsection Change the standard display @example UPDATESTARTUPTTY @end example Set the startup TTY and X-DISPLAY variables to the values of this session. This command is useful to direct future pinentry invocations to another screen. It is only required because there is no way in the ssh-agent protocol to convey this information. @node Agent GETEVENTCOUNTER @subsection Get the Event Counters @example GETEVENTCOUNTER @end example This function return one status line with the current values of the event counters. The event counters are useful to avoid polling by delaying a poll until something has changed. The values are decimal numbers in the range @code{0} to @code{UINT_MAX} and wrapping around to 0. The actual values should not be relied upon; they shall only be used to detect a change. The currently defined counters are: @table @code @item ANY Incremented with any change of any of the other counters. @item KEY Incremented for added or removed private keys. @item CARD Incremented for each change of the card reader's status. @end table @node Agent GETINFO @subsection Return information about the process This is a multipurpose function to return a variety of information. @example GETINFO @var{what} @end example The value of @var{what} specifies the kind of information returned: @table @code @item version Return the version of the program. @item pid Return the process id of the process. @item socket_name Return the name of the socket used to connect the agent. @item ssh_socket_name Return the name of the socket used for SSH connections. If SSH support has not been enabled the error @code{GPG_ERR_NO_DATA} will be returned. @end table @node Agent OPTION @subsection Set options for the session Here is a list of session options which are not yet described with other commands. The general syntax for an Assuan option is: @smallexample OPTION @var{key}=@var{value} @end smallexample @noindent Supported @var{key}s are: @table @code @item agent-awareness This may be used to tell gpg-agent of which gpg-agent version the client is aware of. gpg-agent uses this information to enable features which might break older clients. @item putenv Change the session's environment to be used for the Pinentry. Valid values are: @table @code @item @var{name} Delete envvar @var{name} @item @var{name}= Set envvar @var{name} to the empty string @item @var{name}=@var{value} Set envvar @var{name} to the string @var{value}. @end table @item use-cache-for-signing See Assuan command @code{PKSIGN}. @item allow-pinentry-notify This does not need any value. It is used to enable the PINENTRY_LAUNCHED inquiry. @item pinentry-mode This option is used to change the operation mode of the pinentry. The following values are defined: @table @code @item ask This is the default mode which pops up a pinentry as needed. @item cancel Instead of popping up a pinentry, return the error code @code{GPG_ERR_CANCELED}. @item error Instead of popping up a pinentry, return the error code @code{GPG_ERR_NO_PIN_ENTRY}. @item loopback 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. To disable this feature use @ref{option --no-allow-loopback-pinentry}. @end table @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 is not used a default value is used. @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 passphrase of a key. Values below 65536 are considered to be 0. This 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. @item pretend-request-origin This option switches the connection into a restricted mode which handles all further commands in the same way as they would be handled when originating from the extra or browser socket. Note that this option is not available in the restricted mode. Valid values for this option are: @table @code @item none @itemx local This is a NOP and leaves the connection in the standard way. @item remote Pretend to come from a remote origin in the same way as connections from the @option{--extra-socket}. @item browser Pretend to come from a local web browser in the same way as connections from the @option{--browser-socket}. @end table @end table @mansect see also @ifset isman @command{@gpgname}(1), @command{gpgsm}(1), @command{gpgconf}(1), @command{gpg-connect-agent}(1), @command{scdaemon}(1) @end ifset @include see-also-note.texi