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665 lines
17 KiB
C
665 lines
17 KiB
C
/* passphrase.c - Get a passphrase
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* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003, 2004,
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* 2005, 2006, 2007 Free Software Foundation, Inc.
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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 <stddef.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 <unistd.h>
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#include <assert.h>
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#include <errno.h>
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#ifdef HAVE_LOCALE_H
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#include <locale.h>
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#endif
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#ifdef HAVE_LANGINFO_CODESET
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#include <langinfo.h>
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#endif
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#include "gpg.h"
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#include "util.h"
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#include "options.h"
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#include "ttyio.h"
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#include "cipher.h"
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#include "keydb.h"
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#include "main.h"
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#include "i18n.h"
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#include "status.h"
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#include "call-agent.h"
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static char *fd_passwd = NULL;
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static char *next_pw = NULL;
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static char *last_pw = NULL;
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/* Hash a passphrase using the supplied s2k. If create is true, create
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a new salt or what else must be filled into the s2k for a new key.
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always needs: dek->algo, s2k->mode, s2k->hash_algo. */
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static void
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hash_passphrase ( DEK *dek, char *pw, STRING2KEY *s2k, int create )
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{
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gcry_md_hd_t md;
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int pass, i;
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int used = 0;
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int pwlen = strlen(pw);
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assert ( s2k->hash_algo );
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dek->keylen = gcry_cipher_get_algo_keylen (dek->algo);
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if ( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
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BUG();
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if (gcry_md_open (&md, s2k->hash_algo, 1))
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BUG ();
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for (pass=0; used < dek->keylen ; pass++ )
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{
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if ( pass )
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{
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gcry_md_reset (md);
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for (i=0; i < pass; i++ ) /* Preset the hash context. */
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gcry_md_putc (md, 0 );
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}
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if ( s2k->mode == 1 || s2k->mode == 3 )
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{
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int len2 = pwlen + 8;
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ulong count = len2;
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if ( create && !pass )
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{
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gcry_randomize (s2k->salt, 8, GCRY_STRONG_RANDOM);
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if ( s2k->mode == 3 )
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s2k->count = opt.s2k_count;
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}
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if ( s2k->mode == 3 )
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{
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count = S2K_DECODE_COUNT(s2k->count);
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if ( count < len2 )
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count = len2;
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}
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/* A little bit complicated because we need a ulong for count. */
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while ( count > len2 ) /* maybe iterated+salted */
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{
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gcry_md_write ( md, s2k->salt, 8 );
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gcry_md_write ( md, pw, pwlen );
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count -= len2;
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}
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if ( count < 8 )
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gcry_md_write ( md, s2k->salt, count );
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else
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{
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gcry_md_write ( md, s2k->salt, 8 );
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count -= 8;
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gcry_md_write ( md, pw, count );
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}
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}
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else
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gcry_md_write ( md, pw, pwlen );
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gcry_md_final( md );
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i = gcry_md_get_algo_dlen ( s2k->hash_algo );
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if ( i > dek->keylen - used )
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i = dek->keylen - used;
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memcpy (dek->key+used, gcry_md_read (md, s2k->hash_algo), i);
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used += i;
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}
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gcry_md_close(md);
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}
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int
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have_static_passphrase()
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{
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return !!fd_passwd && opt.batch;
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}
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/****************
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* Set the passphrase to be used for the next query and only for the next
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* one.
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*/
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void
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set_next_passphrase( const char *s )
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{
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xfree(next_pw);
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next_pw = NULL;
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if ( s )
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{
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next_pw = xmalloc_secure( strlen(s)+1 );
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strcpy (next_pw, s );
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}
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}
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/****************
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* Get the last passphrase used in passphrase_to_dek.
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* Note: This removes the passphrase from this modules and
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* the caller must free the result. May return NULL:
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*/
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char *
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get_last_passphrase()
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{
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char *p = last_pw;
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last_pw = NULL;
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return p;
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}
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/* As if we had used the passphrase - make it the last_pw. */
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void
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next_to_last_passphrase(void)
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{
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if (next_pw)
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{
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last_pw=next_pw;
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next_pw=NULL;
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}
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}
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/* Here's an interesting question: since this passphrase was passed in
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on the command line, is there really any point in using secure
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memory for it? I'm going with 'yes', since it doesn't hurt, and
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might help in some small way (swapping). */
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void
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set_passphrase_from_string(const char *pass)
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{
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xfree (fd_passwd);
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fd_passwd = xmalloc_secure(strlen(pass)+1);
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strcpy (fd_passwd, pass);
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}
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void
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read_passphrase_from_fd( int fd )
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{
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int i, len;
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char *pw;
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if ( !opt.batch )
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{ /* Not used but we have to do a dummy read, so that it won't end
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up at the begin of the message if the quite usual trick to
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prepend the passphtrase to the message is used. */
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char buf[1];
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while (!(read (fd, buf, 1) != 1 || *buf == '\n' ))
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;
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*buf = 0;
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return;
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}
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for (pw = NULL, i = len = 100; ; i++ )
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{
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if (i >= len-1 )
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{
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char *pw2 = pw;
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len += 100;
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pw = xmalloc_secure( len );
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if( pw2 )
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{
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memcpy(pw, pw2, i );
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xfree (pw2);
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}
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else
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i=0;
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}
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if (read( fd, pw+i, 1) != 1 || pw[i] == '\n' )
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break;
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}
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pw[i] = 0;
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if (!opt.batch)
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tty_printf("\b\b\b \n" );
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xfree ( fd_passwd );
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fd_passwd = pw;
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}
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/*
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* Ask the GPG Agent for the passphrase.
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* Mode 0: Allow cached passphrase
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* 1: No cached passphrase FIXME: Not really implemented
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* 2: Ditto, but change the text to "repeat entry"
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*
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* Note that TRYAGAIN_TEXT must not be translated. If CANCELED is not
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* NULL, the function does set it to 1 if the user canceled the
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* operation. If CACHEID is not NULL, it will be used as the cacheID
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* for the gpg-agent; if is NULL and a key fingerprint can be
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* computed, this will be used as the cacheid.
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*/
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static char *
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passphrase_get ( u32 *keyid, int mode, const char *cacheid,
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const char *tryagain_text,
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const char *custom_description,
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const char *custom_prompt, int *canceled)
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{
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int rc;
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char *atext = NULL;
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char *pw = NULL;
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PKT_public_key *pk = xmalloc_clear( sizeof *pk );
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byte fpr[MAX_FINGERPRINT_LEN];
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int have_fpr = 0;
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char *orig_codeset;
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char *my_prompt;
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char hexfprbuf[20*2+1];
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const char *my_cacheid;
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if (canceled)
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*canceled = 0;
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#if MAX_FINGERPRINT_LEN < 20
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#error agent needs a 20 byte fingerprint
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#endif
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memset (fpr, 0, MAX_FINGERPRINT_LEN );
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if( keyid && get_pubkey( pk, keyid ) )
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{
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if (pk)
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free_public_key( pk );
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pk = NULL; /* oops: no key for some reason */
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}
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orig_codeset = i18n_switchto_utf8 ();
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if (custom_description)
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atext = native_to_utf8 (custom_description);
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else if ( !mode && pk && keyid )
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{
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char *uid;
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size_t uidlen;
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const char *algo_name = gcry_pk_algo_name ( pk->pubkey_algo );
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const char *timestr;
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char *maink;
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if ( !algo_name )
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algo_name = "?";
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#define KEYIDSTRING _(" (main key ID %s)")
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maink = xmalloc ( strlen (KEYIDSTRING) + keystrlen() + 20 );
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if( keyid[2] && keyid[3] && keyid[0] != keyid[2]
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&& keyid[1] != keyid[3] )
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sprintf( maink, KEYIDSTRING, keystr(&keyid[2]) );
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else
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*maink = 0;
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uid = get_user_id ( keyid, &uidlen );
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timestr = strtimestamp (pk->timestamp);
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#undef KEYIDSTRING
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#define PROMPTSTRING _("Please enter the passphrase to unlock the" \
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" secret key for the OpenPGP certificate:\n" \
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"\"%.*s\"\n" \
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"%u-bit %s key, ID %s,\n" \
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"created %s%s.\n" )
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atext = xmalloc ( 100 + strlen (PROMPTSTRING)
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+ uidlen + 15 + strlen(algo_name) + keystrlen()
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+ strlen (timestr) + strlen (maink) );
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sprintf (atext, PROMPTSTRING,
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(int)uidlen, uid,
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nbits_from_pk (pk), algo_name, keystr(&keyid[0]), timestr,
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maink );
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xfree (uid);
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xfree (maink);
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#undef PROMPTSTRING
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{
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size_t dummy;
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fingerprint_from_pk( pk, fpr, &dummy );
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have_fpr = 1;
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}
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}
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else if (mode == 2 )
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atext = xstrdup ( _("Repeat passphrase\n") );
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else
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atext = xstrdup ( _("Enter passphrase\n") );
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if (!mode && cacheid)
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my_cacheid = cacheid;
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else if (!mode && have_fpr)
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my_cacheid = bin2hex (fpr, 20, hexfprbuf);
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else
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my_cacheid = NULL;
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if (tryagain_text)
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tryagain_text = _(tryagain_text);
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my_prompt = custom_prompt ? native_to_utf8 (custom_prompt): NULL;
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rc = agent_get_passphrase (my_cacheid, tryagain_text, my_prompt, atext, &pw);
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xfree (my_prompt);
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xfree (atext); atext = NULL;
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i18n_switchback (orig_codeset);
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if (!rc)
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;
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else if ( gpg_err_code (rc) == GPG_ERR_CANCELED )
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{
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log_info (_("cancelled by user\n") );
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if (canceled)
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*canceled = 1;
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}
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else
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{
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log_error (_("problem with the agent: %s\n"), gpg_strerror (rc));
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/* Due to limitations in the API of the upper layers they
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consider an error as no passphrase entered. This works in
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most cases but not during key creation where this should
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definitely not happen and let it continue without requiring a
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passphrase. Given that now all the upper layers handle a
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cancel correctly, we simply set the cancel flag now for all
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errors from the agent. */
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if (canceled)
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*canceled = 1;
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}
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if (pk)
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free_public_key( pk );
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if (rc)
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{
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xfree (pw);
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return NULL;
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}
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return pw;
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}
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/*
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* Clear the cached passphrase. If CACHEID is not NULL, it will be
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* used instead of a cache ID derived from KEYID.
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*/
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void
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passphrase_clear_cache ( u32 *keyid, const char *cacheid, int algo )
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{
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int rc;
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(void)algo;
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if (!cacheid)
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{
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PKT_public_key *pk;
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# if MAX_FINGERPRINT_LEN < 20
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# error agent needs a 20 byte fingerprint
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# endif
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byte fpr[MAX_FINGERPRINT_LEN];
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char hexfprbuf[2*20+1];
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size_t dummy;
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pk = xcalloc (1, sizeof *pk);
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if ( !keyid || get_pubkey( pk, keyid ) )
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{
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log_error ("key not found in passphrase_clear_cache\n");
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free_public_key (pk);
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return;
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}
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memset (fpr, 0, MAX_FINGERPRINT_LEN );
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fingerprint_from_pk ( pk, fpr, &dummy );
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bin2hex (fpr, 20, hexfprbuf);
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rc = agent_clear_passphrase (hexfprbuf);
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free_public_key ( pk );
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}
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else
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rc = agent_clear_passphrase (cacheid);
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if (rc)
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log_error (_("problem with the agent: %s\n"), gpg_strerror (rc));
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}
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/****************
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* Ask for a passphrase and return that string.
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*/
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char *
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ask_passphrase (const char *description,
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const char *tryagain_text,
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const char *promptid,
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const char *prompt,
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const char *cacheid, int *canceled)
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{
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char *pw = NULL;
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(void)promptid;
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if (canceled)
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*canceled = 0;
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if (!opt.batch && description)
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{
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if (strchr (description, '%'))
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{
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char *tmp = unescape_percent_string
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((const unsigned char*)description);
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tty_printf ("\n%s\n", tmp);
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xfree (tmp);
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}
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else
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tty_printf ("\n%s\n",description);
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}
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if (have_static_passphrase ())
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{
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pw = xmalloc_secure (strlen(fd_passwd)+1);
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strcpy (pw, fd_passwd);
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}
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else
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pw = passphrase_get (NULL, 0, cacheid,
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tryagain_text, description, prompt,
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canceled );
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if (!pw || !*pw)
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write_status( STATUS_MISSING_PASSPHRASE );
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return pw;
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}
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/* Return a new DEK object Using the string-to-key sepcifier S2K. Use
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KEYID and PUBKEY_ALGO to prompt the user. Returns NULL is the user
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selected to cancel the passphrase entry and if CANCELED is not
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NULL, sets it to true.
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MODE 0: Allow cached passphrase
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1: Ignore cached passphrase
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2: Ditto, but change the text to "repeat entry"
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*/
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DEK *
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passphrase_to_dek (u32 *keyid, int pubkey_algo,
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int cipher_algo, STRING2KEY *s2k, int mode,
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const char *tryagain_text, int *canceled)
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{
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char *pw = NULL;
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DEK *dek;
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STRING2KEY help_s2k;
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int dummy_canceled;
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if (!canceled)
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canceled = &dummy_canceled;
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*canceled = 0;
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if ( !s2k )
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{
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/* This is used for the old rfc1991 mode
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* Note: This must match the code in encode.c with opt.rfc1991 set */
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s2k = &help_s2k;
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s2k->mode = 0;
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s2k->hash_algo = S2K_DIGEST_ALGO;
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}
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/* If we do not have a passphrase available in NEXT_PW and status
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information are request, we print them now. */
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if ( !next_pw && is_status_enabled() )
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{
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char buf[50];
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if ( keyid )
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{
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u32 used_kid[2];
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char *us;
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if ( keyid[2] && keyid[3] )
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{
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used_kid[0] = keyid[2];
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used_kid[1] = keyid[3];
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}
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else
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{
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used_kid[0] = keyid[0];
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used_kid[1] = keyid[1];
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}
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us = get_long_user_id_string ( keyid );
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write_status_text ( STATUS_USERID_HINT, us );
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xfree(us);
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snprintf (buf, sizeof buf -1, "%08lX%08lX %08lX%08lX %d 0",
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(ulong)keyid[0], (ulong)keyid[1],
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(ulong)used_kid[0], (ulong)used_kid[1],
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|
pubkey_algo );
|
|
|
|
write_status_text ( STATUS_NEED_PASSPHRASE, buf );
|
|
}
|
|
else
|
|
{
|
|
snprintf (buf, sizeof buf -1, "%d %d %d",
|
|
cipher_algo, s2k->mode, s2k->hash_algo );
|
|
write_status_text ( STATUS_NEED_PASSPHRASE_SYM, buf );
|
|
}
|
|
}
|
|
|
|
/* If we do have a keyID, we do not have a passphrase available in
|
|
NEXT_PW, we are not running in batch mode and we do not want to
|
|
ignore the passphrase cache (mode!=1), print a prompt with
|
|
information on that key. */
|
|
if ( keyid && !opt.batch && !next_pw && mode!=1 )
|
|
{
|
|
PKT_public_key *pk = xmalloc_clear( sizeof *pk );
|
|
char *p;
|
|
|
|
p = get_user_id_native(keyid);
|
|
tty_printf ("\n");
|
|
tty_printf (_("You need a passphrase to unlock the secret key for\n"
|
|
"user: \"%s\"\n"),p);
|
|
xfree(p);
|
|
|
|
if ( !get_pubkey( pk, keyid ) )
|
|
{
|
|
const char *s = gcry_pk_algo_name ( pk->pubkey_algo );
|
|
|
|
tty_printf (_("%u-bit %s key, ID %s, created %s"),
|
|
nbits_from_pk( pk ), s?s:"?", keystr(keyid),
|
|
strtimestamp(pk->timestamp) );
|
|
if ( keyid[2] && keyid[3]
|
|
&& keyid[0] != keyid[2] && keyid[1] != keyid[3] )
|
|
{
|
|
if ( keystrlen () > 10 )
|
|
{
|
|
tty_printf ("\n");
|
|
tty_printf (_(" (subkey on main key ID %s)"),
|
|
keystr(&keyid[2]) );
|
|
}
|
|
else
|
|
tty_printf ( _(" (main key ID %s)"), keystr(&keyid[2]) );
|
|
}
|
|
tty_printf("\n");
|
|
}
|
|
|
|
tty_printf("\n");
|
|
if (pk)
|
|
free_public_key( pk );
|
|
}
|
|
|
|
if ( next_pw )
|
|
{
|
|
/* Simply return the passphrase we already have in NEXT_PW. */
|
|
pw = next_pw;
|
|
next_pw = NULL;
|
|
}
|
|
else if ( have_static_passphrase () )
|
|
{
|
|
/* Return the passphrase we have stored in FD_PASSWD. */
|
|
pw = xmalloc_secure ( strlen(fd_passwd)+1 );
|
|
strcpy ( pw, fd_passwd );
|
|
}
|
|
else
|
|
{
|
|
/* Divert to the gpg-agent. */
|
|
pw = passphrase_get ( keyid, mode == 2? 1: 0, NULL,
|
|
tryagain_text, NULL, NULL, canceled );
|
|
if (*canceled)
|
|
{
|
|
xfree (pw);
|
|
write_status( STATUS_MISSING_PASSPHRASE );
|
|
return NULL;
|
|
}
|
|
if (!pw)
|
|
pw = xstrdup ("");
|
|
if ( *pw && mode == 2 )
|
|
{
|
|
int i;
|
|
for(i=0;i<opt.passwd_repeat;i++)
|
|
{
|
|
char *pw2 = passphrase_get ( keyid, 2, NULL, NULL, NULL,
|
|
NULL, canceled );
|
|
if (*canceled)
|
|
{
|
|
xfree (pw);
|
|
xfree (pw2);
|
|
write_status( STATUS_MISSING_PASSPHRASE );
|
|
return NULL;
|
|
}
|
|
if (!pw2)
|
|
pw2 = xstrdup ("");
|
|
if ( strcmp(pw, pw2) )
|
|
{
|
|
xfree(pw2);
|
|
xfree(pw);
|
|
return NULL;
|
|
}
|
|
xfree(pw2);
|
|
}
|
|
}
|
|
}
|
|
|
|
if ( !pw || !*pw )
|
|
write_status( STATUS_MISSING_PASSPHRASE );
|
|
|
|
/* Hash the passphrase and store it in a newly allocated DEK object.
|
|
Keep a copy of the passphrase in LAST_PW for use by
|
|
get_last_passphrase(). */
|
|
dek = xmalloc_secure_clear ( sizeof *dek );
|
|
dek->algo = cipher_algo;
|
|
if ( !*pw && mode == 2 )
|
|
dek->keylen = 0;
|
|
else
|
|
hash_passphrase( dek, pw, s2k, mode==2 );
|
|
xfree(last_pw);
|
|
last_pw = pw;
|
|
return dek;
|
|
}
|