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5b84b0d660
* common/stringhelp.c (utf8_charcount): Take additional parameter, len. Process at most LEN bytes. -- Signed-off-by: Neal H. Walfield <neal@g10code.com>
618 lines
17 KiB
C
618 lines
17 KiB
C
/* genkey.c - Generate a keypair
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* Copyright (C) 2002, 2003, 2004, 2007, 2010 Free Software Foundation, Inc.
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* Copyright (C) 2015 g10 Code GmbH.
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*
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* This file is part of GnuPG.
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*
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* GnuPG is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 3 of the License, or
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* (at your option) any later version.
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*
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* GnuPG is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include <config.h>
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <ctype.h>
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#include <assert.h>
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#include "agent.h"
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#include "i18n.h"
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#include "exechelp.h"
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#include "sysutils.h"
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static int
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store_key (gcry_sexp_t private, const char *passphrase, int force,
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unsigned long s2k_count)
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{
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int rc;
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unsigned char *buf;
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size_t len;
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unsigned char grip[20];
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if ( !gcry_pk_get_keygrip (private, grip) )
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{
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log_error ("can't calculate keygrip\n");
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return gpg_error (GPG_ERR_GENERAL);
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}
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len = gcry_sexp_sprint (private, GCRYSEXP_FMT_CANON, NULL, 0);
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assert (len);
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buf = gcry_malloc_secure (len);
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if (!buf)
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return out_of_core ();
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len = gcry_sexp_sprint (private, GCRYSEXP_FMT_CANON, buf, len);
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assert (len);
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if (passphrase)
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{
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unsigned char *p;
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rc = agent_protect (buf, passphrase, &p, &len, s2k_count);
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if (rc)
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{
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xfree (buf);
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return rc;
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}
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xfree (buf);
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buf = p;
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}
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rc = agent_write_private_key (grip, buf, len, force);
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xfree (buf);
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return rc;
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}
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/* Count the number of non-alpha characters in S. Control characters
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and non-ascii characters are not considered. */
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static size_t
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nonalpha_count (const char *s)
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{
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size_t n;
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for (n=0; *s; s++)
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if (isascii (*s) && ( isdigit (*s) || ispunct (*s) ))
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n++;
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return n;
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}
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/* Check PW against a list of pattern. Return 0 if PW does not match
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these pattern. */
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static int
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check_passphrase_pattern (ctrl_t ctrl, const char *pw)
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{
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gpg_error_t err = 0;
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const char *pgmname = gnupg_module_name (GNUPG_MODULE_NAME_CHECK_PATTERN);
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FILE *infp;
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const char *argv[10];
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pid_t pid;
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int result, i;
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(void)ctrl;
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infp = gnupg_tmpfile ();
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if (!infp)
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{
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err = gpg_error_from_syserror ();
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log_error (_("error creating temporary file: %s\n"), gpg_strerror (err));
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return 1; /* Error - assume password should not be used. */
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}
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if (fwrite (pw, strlen (pw), 1, infp) != 1)
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{
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err = gpg_error_from_syserror ();
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log_error (_("error writing to temporary file: %s\n"),
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gpg_strerror (err));
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fclose (infp);
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return 1; /* Error - assume password should not be used. */
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}
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fseek (infp, 0, SEEK_SET);
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clearerr (infp);
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i = 0;
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argv[i++] = "--null";
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argv[i++] = "--",
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argv[i++] = opt.check_passphrase_pattern,
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argv[i] = NULL;
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assert (i < sizeof argv);
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if (gnupg_spawn_process_fd (pgmname, argv, fileno (infp), -1, -1, &pid))
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result = 1; /* Execute error - assume password should no be used. */
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else if (gnupg_wait_process (pgmname, pid, 1, NULL))
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result = 1; /* Helper returned an error - probably a match. */
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else
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result = 0; /* Success; i.e. no match. */
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gnupg_release_process (pid);
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/* Overwrite our temporary file. */
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fseek (infp, 0, SEEK_SET);
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clearerr (infp);
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for (i=((strlen (pw)+99)/100)*100; i > 0; i--)
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putc ('\xff', infp);
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fflush (infp);
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fclose (infp);
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return result;
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}
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static int
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take_this_one_anyway2 (ctrl_t ctrl, const char *desc, const char *anyway_btn)
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{
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gpg_error_t err;
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if (opt.enforce_passphrase_constraints)
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{
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err = agent_show_message (ctrl, desc, L_("Enter new passphrase"));
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if (!err)
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err = gpg_error (GPG_ERR_CANCELED);
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}
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else
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err = agent_get_confirmation (ctrl, desc,
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anyway_btn, L_("Enter new passphrase"), 0);
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return err;
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}
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static int
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take_this_one_anyway (ctrl_t ctrl, const char *desc)
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{
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return take_this_one_anyway2 (ctrl, desc, L_("Take this one anyway"));
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}
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/* Check whether the passphrase PW is suitable. Returns 0 if the
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passphrase is suitable and true if it is not and the user should be
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asked to provide a different one. If FAILED_CONSTRAINT is set, a
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message describing the problem is returned in
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*FAILED_CONSTRAINT. */
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int
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check_passphrase_constraints (ctrl_t ctrl, const char *pw,
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char **failed_constraint)
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{
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gpg_error_t err = 0;
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unsigned int minlen = opt.min_passphrase_len;
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unsigned int minnonalpha = opt.min_passphrase_nonalpha;
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char *msg1 = NULL;
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char *msg2 = NULL;
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char *msg3 = NULL;
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if (ctrl && ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK)
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return 0;
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if (!pw)
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pw = "";
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/* The first check is to warn about an empty passphrase. */
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if (!*pw)
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{
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const char *desc = (opt.enforce_passphrase_constraints?
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L_("You have not entered a passphrase!%0A"
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"An empty passphrase is not allowed.") :
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L_("You have not entered a passphrase - "
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"this is in general a bad idea!%0A"
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"Please confirm that you do not want to "
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"have any protection on your key."));
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err = 1;
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if (failed_constraint)
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{
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if (opt.enforce_passphrase_constraints)
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*failed_constraint = xstrdup (desc);
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else
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err = take_this_one_anyway2 (ctrl, desc,
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L_("Yes, protection is not needed"));
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}
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goto leave;
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}
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/* Now check the constraints and collect the error messages unless
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in in silent mode which returns immediately. */
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if (utf8_charcount (pw, -1) < minlen )
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{
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if (!failed_constraint)
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{
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err = gpg_error (GPG_ERR_INV_PASSPHRASE);
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goto leave;
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}
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msg1 = xtryasprintf
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( ngettext ("A passphrase should be at least %u character long.",
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"A passphrase should be at least %u characters long.",
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minlen), minlen );
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if (!msg1)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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}
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if (nonalpha_count (pw) < minnonalpha )
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{
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if (!failed_constraint)
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{
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err = gpg_error (GPG_ERR_INV_PASSPHRASE);
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goto leave;
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}
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msg2 = xtryasprintf
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( ngettext ("A passphrase should contain at least %u digit or%%0A"
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"special character.",
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"A passphrase should contain at least %u digits or%%0A"
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"special characters.",
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minnonalpha), minnonalpha );
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if (!msg2)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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}
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/* If configured check the passphrase against a list of known words
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and pattern. The actual test is done by an external program.
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The warning message is generic to give the user no hint on how to
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circumvent this list. */
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if (*pw && opt.check_passphrase_pattern &&
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check_passphrase_pattern (ctrl, pw))
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{
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if (!failed_constraint)
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{
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err = gpg_error (GPG_ERR_INV_PASSPHRASE);
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goto leave;
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}
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msg3 = xtryasprintf
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(L_("A passphrase may not be a known term or match%%0A"
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"certain pattern."));
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if (!msg3)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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}
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if (failed_constraint && (msg1 || msg2 || msg3))
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{
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char *msg;
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size_t n;
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msg = strconcat
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(L_("Warning: You have entered an insecure passphrase."),
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"%0A%0A",
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msg1? msg1 : "", msg1? "%0A" : "",
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msg2? msg2 : "", msg2? "%0A" : "",
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msg3? msg3 : "", msg3? "%0A" : "",
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NULL);
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if (!msg)
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{
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err = gpg_error_from_syserror ();
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goto leave;
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}
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/* Strip a trailing "%0A". */
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n = strlen (msg);
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if (n > 3 && !strcmp (msg + n - 3, "%0A"))
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msg[n-3] = 0;
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err = 1;
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if (opt.enforce_passphrase_constraints)
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*failed_constraint = msg;
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else
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{
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err = take_this_one_anyway (ctrl, msg);
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xfree (msg);
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}
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}
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leave:
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xfree (msg1);
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xfree (msg2);
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xfree (msg3);
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return err;
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}
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/* Callback function to compare the first entered PIN with the one
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currently being entered. */
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static gpg_error_t
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reenter_compare_cb (struct pin_entry_info_s *pi)
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{
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const char *pin1 = pi->check_cb_arg;
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if (!strcmp (pin1, pi->pin))
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return 0; /* okay */
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return gpg_error (GPG_ERR_BAD_PASSPHRASE);
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}
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/* Ask the user for a new passphrase using PROMPT. On success the
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function returns 0 and store the passphrase at R_PASSPHRASE; if the
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user opted not to use a passphrase NULL will be stored there. The
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user needs to free the returned string. In case of an error and
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error code is returned and NULL stored at R_PASSPHRASE. */
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gpg_error_t
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agent_ask_new_passphrase (ctrl_t ctrl, const char *prompt,
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char **r_passphrase)
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{
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gpg_error_t err;
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const char *text1 = prompt;
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const char *text2 = L_("Please re-enter this passphrase");
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char *initial_errtext = NULL;
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struct pin_entry_info_s *pi, *pi2;
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*r_passphrase = NULL;
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if (ctrl->pinentry_mode == PINENTRY_MODE_LOOPBACK)
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{
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size_t size;
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size_t len = 100;
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unsigned char *buffer;
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err = pinentry_loopback(ctrl, "NEW_PASSPHRASE", &buffer, &size, len);
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if (!err)
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{
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if (size)
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{
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buffer[size] = 0;
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*r_passphrase = buffer;
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}
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else
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*r_passphrase = NULL;
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}
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return err;
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}
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pi = gcry_calloc_secure (1, sizeof (*pi) + MAX_PASSPHRASE_LEN + 1);
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if (!pi)
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return gpg_error_from_syserror ();
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pi2 = gcry_calloc_secure (1, sizeof (*pi2) + MAX_PASSPHRASE_LEN + 1);
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if (!pi2)
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{
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err = gpg_error_from_syserror ();
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xfree (pi2);
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return err;
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}
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pi->max_length = MAX_PASSPHRASE_LEN + 1;
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pi->max_tries = 3;
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pi->with_qualitybar = 1;
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pi->with_repeat = 1;
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pi2->max_length = MAX_PASSPHRASE_LEN + 1;
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pi2->max_tries = 3;
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pi2->check_cb = reenter_compare_cb;
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pi2->check_cb_arg = pi->pin;
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next_try:
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err = agent_askpin (ctrl, text1, NULL, initial_errtext, pi, NULL, 0);
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xfree (initial_errtext);
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initial_errtext = NULL;
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if (!err)
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{
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if (check_passphrase_constraints (ctrl, pi->pin, &initial_errtext))
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{
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pi->failed_tries = 0;
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pi2->failed_tries = 0;
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goto next_try;
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}
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/* Unless the passphrase is empty or the pinentry told us that
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it already did the repetition check, ask to confirm it. */
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if (*pi->pin && !pi->repeat_okay)
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{
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err = agent_askpin (ctrl, text2, NULL, NULL, pi2, NULL, 0);
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if (gpg_err_code (err) == GPG_ERR_BAD_PASSPHRASE)
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{ /* The re-entered one did not match and the user did not
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hit cancel. */
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initial_errtext = xtrystrdup (L_("does not match - try again"));
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if (initial_errtext)
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goto next_try;
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err = gpg_error_from_syserror ();
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}
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}
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}
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if (!err && *pi->pin)
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{
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/* User wants a passphrase. */
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*r_passphrase = xtrystrdup (pi->pin);
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if (!*r_passphrase)
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err = gpg_error_from_syserror ();
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}
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xfree (initial_errtext);
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xfree (pi2);
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xfree (pi);
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return err;
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}
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/* Generate a new keypair according to the parameters given in
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KEYPARAM. If CACHE_NONCE is given first try to lookup a passphrase
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using the cache nonce. If NO_PROTECTION is true the key will not
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be protected by a passphrase. If OVERRIDE_PASSPHRASE is true that
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passphrase will be used for the new key. */
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int
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agent_genkey (ctrl_t ctrl, const char *cache_nonce,
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const char *keyparam, size_t keyparamlen, int no_protection,
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const char *override_passphrase, int preset, membuf_t *outbuf)
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{
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gcry_sexp_t s_keyparam, s_key, s_private, s_public;
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char *passphrase_buffer = NULL;
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const char *passphrase;
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int rc;
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size_t len;
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char *buf;
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rc = gcry_sexp_sscan (&s_keyparam, NULL, keyparam, keyparamlen);
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if (rc)
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{
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log_error ("failed to convert keyparam: %s\n", gpg_strerror (rc));
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return gpg_error (GPG_ERR_INV_DATA);
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}
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/* Get the passphrase now, cause key generation may take a while. */
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if (override_passphrase)
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passphrase = override_passphrase;
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else if (no_protection || !cache_nonce)
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passphrase = NULL;
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else
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{
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passphrase_buffer = agent_get_cache (cache_nonce, CACHE_MODE_NONCE);
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passphrase = passphrase_buffer;
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}
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if (passphrase || no_protection)
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;
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else
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{
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rc = agent_ask_new_passphrase (ctrl,
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L_("Please enter the passphrase to%0A"
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"protect your new key"),
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&passphrase_buffer);
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if (rc)
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return rc;
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passphrase = passphrase_buffer;
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}
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rc = gcry_pk_genkey (&s_key, s_keyparam );
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gcry_sexp_release (s_keyparam);
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if (rc)
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{
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log_error ("key generation failed: %s\n", gpg_strerror (rc));
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xfree (passphrase_buffer);
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return rc;
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}
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/* break out the parts */
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s_private = gcry_sexp_find_token (s_key, "private-key", 0);
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if (!s_private)
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{
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log_error ("key generation failed: invalid return value\n");
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gcry_sexp_release (s_key);
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xfree (passphrase_buffer);
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return gpg_error (GPG_ERR_INV_DATA);
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}
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s_public = gcry_sexp_find_token (s_key, "public-key", 0);
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if (!s_public)
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{
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log_error ("key generation failed: invalid return value\n");
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gcry_sexp_release (s_private);
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gcry_sexp_release (s_key);
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xfree (passphrase_buffer);
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return gpg_error (GPG_ERR_INV_DATA);
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}
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gcry_sexp_release (s_key); s_key = NULL;
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/* store the secret key */
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if (DBG_CRYPTO)
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log_debug ("storing private key\n");
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rc = store_key (s_private, passphrase, 0, ctrl->s2k_count);
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if (!rc)
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{
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if (!cache_nonce)
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{
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char tmpbuf[12];
|
||
gcry_create_nonce (tmpbuf, 12);
|
||
cache_nonce = bin2hex (tmpbuf, 12, NULL);
|
||
}
|
||
if (cache_nonce
|
||
&& !no_protection
|
||
&& !agent_put_cache (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 (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);
|
||
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);
|
||
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);
|
||
}
|
||
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);
|
||
if (!err && passphrase_addr)
|
||
*passphrase_addr = pass;
|
||
else
|
||
xfree (pass);
|
||
}
|
||
|
||
return err;
|
||
}
|