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6639bbf699
gnupg/g10/passphrase.c
Werner Koch 6639bbf699 * passphrase.c (agent_get_passphrase): Add new arg CACHEID. 
Changed all callers.
(ask_passphrase): Add new arg CACHEID and use it in agent mode.
Changed all callers.
(passphrase_clear_cache): New arg CACHEID.  Changed all callers.
* cardglue.c (format_cacheid): New.
(pin_cb): Compute a cache ID.
(agent_scd_pksign, agent_scd_pkdecrypt): Use it.
(agent_clear_pin_cache): New.
* card-util.c (change_pin): Clear the PIN cache.
(check_pin_for_key_operation): Ditto.
2005-05-03 22:27:07 +00:00

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/* passphrase.c - Get a passphrase
* Copyright (C) 1998, 1999, 2000, 2001, 2002, 2003,
* 2004, 2005 Free Software Foundation, Inc.
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include <config.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <assert.h>
#if !defined(HAVE_DOSISH_SYSTEM) && !defined(__riscos__)
#include <sys/socket.h>
#include <sys/un.h>
#endif
#if defined (_WIN32)
#include <windows.h>
#endif
#include <errno.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#ifdef HAVE_LANGINFO_CODESET
#include <langinfo.h>
#endif
#include "util.h"
#include "memory.h"
#include "options.h"
#include "ttyio.h"
#include "cipher.h"
#include "keydb.h"
#include "main.h"
#include "i18n.h"
#include "status.h"
#ifdef ENABLE_AGENT_SUPPORT
#include "assuan.h"
#endif /*ENABLE_AGENT_SUPPORT*/
#define buftou32( p ) ((*(byte*)(p) << 24) | (*((byte*)(p)+1)<< 16) | \
(*((byte*)(p)+2) << 8) | (*((byte*)(p)+3)))
#define u32tobuf( p, a ) do { \
((byte*)p)[0] = (byte)((a) >> 24); \
((byte*)p)[1] = (byte)((a) >> 16); \
((byte*)p)[2] = (byte)((a) >> 8); \
((byte*)p)[3] = (byte)((a) ); \
} while(0)
#define digitp(p) (*(p) >= '0' && *(p) <= '9')
#define hexdigitp(a) (digitp (a) \
|| (*(a) >= 'A' && *(a) <= 'F') \
|| (*(a) >= 'a' && *(a) <= 'f'))
#define xtoi_1(p) (*(p) <= '9'? (*(p)- '0'): \
*(p) <= 'F'? (*(p)-'A'+10):(*(p)-'a'+10))
#define xtoi_2(p) ((xtoi_1(p) * 16) + xtoi_1((p)+1))
static char *fd_passwd = NULL;
static char *next_pw = NULL;
static char *last_pw = NULL;
#if defined (_WIN32)
static int read_fd = 0;
static int write_fd = 0;
#endif
static void hash_passphrase( DEK *dek, char *pw, STRING2KEY *s2k, int create );
int
have_static_passphrase()
{
if ( opt.use_agent )
return 0;
return !!fd_passwd;
}
/****************
* Set the passphrase to be used for the next query and only for the next
* one.
*/
void
set_next_passphrase( const char *s )
{
m_free(next_pw);
next_pw = NULL;
if( s ) {
next_pw = m_alloc_secure( strlen(s)+1 );
strcpy(next_pw, s );
}
}
/****************
* Get the last passphrase used in passphrase_to_dek.
* Note: This removes the passphrase from this modules and
* the caller must free the result. May return NULL:
*/
char *
get_last_passphrase()
{
char *p = last_pw;
last_pw = NULL;
return p;
}
void
read_passphrase_from_fd( int fd )
{
int i, len;
char *pw;
if ( opt.use_agent )
{ /* Not used but we have to do a dummy read, so that it won't end
up at the begin of the message if the quite usual trick to
prepend the passphtrase to the message is used. */
char buf[1];
while (!(read (fd, buf, 1) != 1 || *buf == '\n' ))
;
*buf = 0;
return;
}
if (!opt.batch )
tty_printf("Reading passphrase from file descriptor %d ...", fd );
for (pw = NULL, i = len = 100; ; i++ )
{
if (i >= len-1 )
{
char *pw2 = pw;
len += 100;
pw = m_alloc_secure( len );
if( pw2 )
{
memcpy(pw, pw2, i );
m_free (pw2);
}
else
i=0;
}
if (read( fd, pw+i, 1) != 1 || pw[i] == '\n' )
break;
}
pw[i] = 0;
if (!opt.batch)
tty_printf("\b\b\b \n" );
m_free( fd_passwd );
fd_passwd = pw;
}
#ifdef ENABLE_AGENT_SUPPORT
/* Send one option to the gpg-agent. */
static int
agent_send_option (assuan_context_t ctx, const char *name, const char *value)
{
char *line;
int rc;
if (!value || !*value)
return 0; /* Avoid sending empty option values. */
line = xmalloc (7 + strlen (name) + 1 + strlen (value) + 1);
strcpy (stpcpy (stpcpy (stpcpy (line, "OPTION "), name), "="), value);
rc = assuan_transact (ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
xfree (line);
return rc? -1 : 0;
}
/* Send all required options to the gpg-agent. */
static int
agent_send_all_options (assuan_context_t ctx)
{
char *dft_display = NULL;
const char *dft_ttyname = NULL;
char *dft_ttytype = NULL;
char *old_lc = NULL;
char *dft_lc = NULL;
int rc = 0;
dft_display = getenv ("DISPLAY");
if (opt.display || dft_display)
{
if (agent_send_option (ctx, "display",
opt.display ? opt.display : dft_display))
return -1;
}
if (!opt.ttyname)
{
const char *tmp;
dft_ttyname = getenv ("GPG_TTY");
if ((!dft_ttyname || !*dft_ttyname) && (tmp=ttyname (0)))
dft_ttyname = tmp;
if ((!dft_ttyname || !*dft_ttyname) && (tmp=tty_get_ttyname ()))
dft_ttyname = tmp;
}
if (opt.ttyname || dft_ttyname)
{
if (agent_send_option (ctx, "ttyname",
opt.ttyname ? opt.ttyname : dft_ttyname))
return -1;
}
dft_ttytype = getenv ("TERM");
if (opt.ttytype || (dft_ttyname && dft_ttytype))
{
if (agent_send_option (ctx, "ttytype",
opt.ttyname ? opt.ttytype : dft_ttytype))
return -1;
}
#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
old_lc = setlocale (LC_CTYPE, NULL);
if (old_lc)
old_lc = m_strdup (old_lc);
dft_lc = setlocale (LC_CTYPE, "");
#endif
if (opt.lc_ctype || (dft_ttyname && dft_lc))
{
rc = agent_send_option (ctx, "lc-ctype",
opt.lc_ctype ? opt.lc_ctype : dft_lc);
}
#if defined(HAVE_SETLOCALE) && defined(LC_CTYPE)
if (old_lc)
{
setlocale (LC_CTYPE, old_lc);
m_free (old_lc);
}
#endif
if (rc)
return rc;
#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
old_lc = setlocale (LC_MESSAGES, NULL);
if (old_lc)
old_lc = m_strdup (old_lc);
dft_lc = setlocale (LC_MESSAGES, "");
#endif
if (opt.lc_messages || (dft_ttyname && dft_lc))
{
rc = agent_send_option (ctx, "lc-messages",
opt.lc_messages ? opt.lc_messages : dft_lc);
}
#if defined(HAVE_SETLOCALE) && defined(LC_MESSAGES)
if (old_lc)
{
setlocale (LC_MESSAGES, old_lc);
m_free (old_lc);
}
#endif
return rc;
}
#endif /*ENABLE_AGENT_SUPPORT*/
/*
* Open a connection to the agent and initializes the connection.
* Returns: -1 on error; on success a file descriptor for that
* connection is returned.
*/
#ifdef ENABLE_AGENT_SUPPORT
static assuan_context_t
agent_open (void)
{
int rc;
assuan_context_t ctx;
char *infostr, *p;
int prot;
int pid;
if (opt.gpg_agent_info)
infostr = xstrdup (opt.gpg_agent_info);
else
{
infostr = getenv ( "GPG_AGENT_INFO" );
if (!infostr || !*infostr)
{
log_error (_("gpg-agent is not available in this session\n"));
opt.use_agent = 0;
return NULL;
}
infostr = xstrdup ( infostr );
}
if ( !(p = strchr (infostr, PATHSEP_C)) || p == infostr)
{
log_error ( _("malformed GPG_AGENT_INFO environment variable\n"));
xfree (infostr);
opt.use_agent = 0;
return NULL;
}
*p++ = 0;
pid = atoi (p);
while (*p && *p != PATHSEP_C)
p++;
prot = *p? atoi (p+1) : 0;
if (prot != 1)
{
log_error (_("gpg-agent protocol version %d is not supported\n"), prot);
xfree (infostr);
opt.use_agent = 0;
return NULL;
}
rc = assuan_socket_connect (&ctx, infostr, pid);
if (rc)
{
log_error ( _("can't connect to `%s': %s\n"),
infostr, assuan_strerror (rc));
xfree (infostr );
opt.use_agent = 0;
return NULL;
}
xfree (infostr);
if (agent_send_all_options (ctx))
{
log_error (_("problem with the agent - disabling agent use\n"));
assuan_disconnect (ctx);
opt.use_agent = 0;
return NULL;
}
return ctx;
}
#endif/*ENABLE_AGENT_SUPPORT*/
#ifdef ENABLE_AGENT_SUPPORT
static void
agent_close (assuan_context_t ctx)
{
assuan_disconnect (ctx);
}
#endif /*ENABLE_AGENT_SUPPORT*/
/* Copy the text ATEXT into the buffer P and do plus '+' and percent
escaping. Note that the provided buffer needs to be 3 times the
size of ATEXT plus 1. Returns a pointer to the leading Nul in P. */
#ifdef ENABLE_AGENT_SUPPORT
static char *
percent_plus_escape (char *p, const char *atext)
{
const unsigned char *s;
for (s=atext; *s; s++)
{
if (*s < ' ' || *s == '+')
{
sprintf (p, "%%%02X", *s);
p += 3;
}
else if (*s == ' ')
*p++ = '+';
else
*p++ = *s;
}
*p = 0;
return p;
}
#endif /*ENABLE_AGENT_SUPPORT*/
#ifdef ENABLE_AGENT_SUPPORT
/* Object for the agent_okay_cb function. */
struct agent_okay_cb_s {
char *pw;
};
/* A callback used to get the passphrase from the okay line. See
agent-get_passphrase for details. LINE is the rest of the OK
status line without leading white spaces. */
static assuan_error_t
agent_okay_cb (void *opaque, const char *line)
{
struct agent_okay_cb_s *parm = opaque;
int i;
/* Note: If the malloc below fails we won't be able to wipe the
memory at LINE given the current implementation of the Assuan
code. There is no easy ay around this w/o adding a lot of more
memory function code to allow wiping arbitrary stuff on memory
failure. */
parm->pw = xmalloc_secure (strlen (line)/2+2);
for (i=0; hexdigitp (line) && hexdigitp (line+1); line += 2)
parm->pw[i++] = xtoi_2 (line);
parm->pw[i] = 0;
return 0;
}
#endif /*ENABLE_AGENT_SUPPORT*/
/*
* Ask the GPG Agent for the passphrase.
* Mode 0: Allow cached passphrase
* 1: No cached passphrase FIXME: Not really implemented
* 2: Ditto, but change the text to "repeat entry"
*
* Note that TRYAGAIN_TEXT must not be translated. If canceled is not
* NULL, the function does set it to 1 if the user canceled the
* operation. If CACHEID is not NULL, it will be used as the cacheID
* for the gpg-agent; if is NULL and a key fingerprint can be
* computed, this will be used as the cacheid.
*/
static char *
agent_get_passphrase ( u32 *keyid, int mode, const char *cacheid,
const char *tryagain_text,
const char *custom_description,
const char *custom_prompt, int *canceled)
{
#ifdef ENABLE_AGENT_SUPPORT
char *atext = NULL;
assuan_context_t ctx = NULL;
char *pw = NULL;
PKT_public_key *pk = m_alloc_clear( sizeof *pk );
byte fpr[MAX_FINGERPRINT_LEN];
int have_fpr = 0;
char *orig_codeset = NULL;
if (canceled)
*canceled = 0;
#if MAX_FINGERPRINT_LEN < 20
#error agent needs a 20 byte fingerprint
#endif
memset (fpr, 0, MAX_FINGERPRINT_LEN );
if( keyid && get_pubkey( pk, keyid ) )
{
if (pk)
free_public_key( pk );
pk = NULL; /* oops: no key for some reason */
}
#ifdef ENABLE_NLS
/* The Assuan agent protocol requires us to transmit utf-8 strings */
orig_codeset = bind_textdomain_codeset (PACKAGE, NULL);
#ifdef HAVE_LANGINFO_CODESET
if (!orig_codeset)
orig_codeset = nl_langinfo (CODESET);
#endif
if (orig_codeset)
{ /* We only switch when we are able to restore the codeset later. */
orig_codeset = m_strdup (orig_codeset);
if (!bind_textdomain_codeset (PACKAGE, "utf-8"))
orig_codeset = NULL;
}
#endif
if ( !(ctx = agent_open ()) )
goto failure;
if (custom_description)
atext = native_to_utf8 (custom_description);
else if ( !mode && pk && keyid )
{
char *uid;
size_t uidlen;
const char *algo_name = pubkey_algo_to_string ( pk->pubkey_algo );
const char *timestr;
char *maink;
if ( !algo_name )
algo_name = "?";
#define KEYIDSTRING _(" (main key ID %s)")
maink = m_alloc ( strlen (KEYIDSTRING) + keystrlen() + 20 );
if( keyid[2] && keyid[3] && keyid[0] != keyid[2]
&& keyid[1] != keyid[3] )
sprintf( maink, KEYIDSTRING, keystr(&keyid[2]) );
else
*maink = 0;
uid = get_user_id ( keyid, &uidlen );
timestr = strtimestamp (pk->timestamp);
#undef KEYIDSTRING
#define PROMPTSTRING _("You need a passphrase to unlock the secret" \
" key for user:\n" \
"\"%.*s\"\n" \
"%u-bit %s key, ID %s, created %s%s\n" )
atext = m_alloc ( 100 + strlen (PROMPTSTRING)
+ uidlen + 15 + strlen(algo_name) + keystrlen()
+ strlen (timestr) + strlen (maink) );
sprintf (atext, PROMPTSTRING,
(int)uidlen, uid,
nbits_from_pk (pk), algo_name, keystr(&keyid[0]), timestr,
maink );
m_free (uid);
m_free (maink);
#undef PROMPTSTRING
{
size_t dummy;
fingerprint_from_pk( pk, fpr, &dummy );
have_fpr = 1;
}
}
else if (mode == 2 )
atext = m_strdup ( _("Repeat passphrase\n") );
else
atext = m_strdup ( _("Enter passphrase\n") );
{
char *line, *p;
int i, rc;
struct agent_okay_cb_s okay_cb_parm;
if (!tryagain_text)
tryagain_text = "X";
else
tryagain_text = _(tryagain_text);
/* We allocate 23 times the needed space for thye texts so that
there is enough space for escaping. */
line = xmalloc (15 + 46
+ 3*strlen (atext)
+ 3*strlen (custom_prompt? custom_prompt:"")
+ (cacheid? (3*strlen (cacheid)): 0)
+ 3*strlen (tryagain_text)
+ 1);
strcpy (line, "GET_PASSPHRASE ");
p = line+15;
if (!mode && cacheid)
{
p = percent_plus_escape (p, cacheid);
}
else if (!mode && have_fpr)
{
for (i=0; i < 20; i++, p +=2 )
sprintf (p, "%02X", fpr[i]);
}
else
*p++ = 'X'; /* No caching. */
*p++ = ' ';
p = percent_plus_escape (p, tryagain_text);
*p++ = ' ';
/* The prompt. */
if (custom_prompt)
{
char *tmp = native_to_utf8 (custom_prompt);
p = percent_plus_escape (p, tmp);
xfree (tmp);
}
else
*p++ = 'X'; /* Use the standard prompt. */
*p++ = ' ';
/* Copy description. */
percent_plus_escape (p, atext);
/* Call gpg-agent. */
memset (&okay_cb_parm, 0, sizeof okay_cb_parm);
rc = assuan_transact2 (ctx, line, NULL, NULL, NULL, NULL, NULL, NULL,
agent_okay_cb, &okay_cb_parm);
xfree (line);
xfree (atext); atext = NULL;
if (!rc)
{
assert (okay_cb_parm.pw);
pw = okay_cb_parm.pw;
agent_close (ctx);
if (pk)
free_public_key( pk );
#ifdef ENABLE_NLS
if (orig_codeset)
bind_textdomain_codeset (PACKAGE, orig_codeset);
#endif
xfree (orig_codeset);
return pw;
}
else if (rc && (rc & 0xffff) == 99)
{
/* 99 is GPG_ERR_CANCELED. */
log_info (_("cancelled by user\n") );
if (canceled)
*canceled = 1;
}
else
{
log_error (_("problem with the agent - disabling agent use\n"));
opt.use_agent = 0;
}
}
failure:
#ifdef ENABLE_NLS
if (orig_codeset)
bind_textdomain_codeset (PACKAGE, orig_codeset);
#endif
xfree (atext);
agent_close (ctx);
xfree (pw );
if (pk)
free_public_key( pk );
#endif /*ENABLE_AGENT_SUPPORT*/
return NULL;
}
/*
* Clear the cached passphrase. If CACHEID is not NULL, it will be
* used instead of a cache ID derived from KEYID.
*/
void
passphrase_clear_cache ( u32 *keyid, const char *cacheid, int algo )
{
#ifdef ENABLE_AGENT_SUPPORT
assuan_context_t ctx = NULL;
PKT_public_key *pk;
byte fpr[MAX_FINGERPRINT_LEN];
#if MAX_FINGERPRINT_LEN < 20
#error agent needs a 20 byte fingerprint
#endif
if (!opt.use_agent)
return;
if (!cacheid)
{
pk = xcalloc (1, sizeof *pk);
memset (fpr, 0, MAX_FINGERPRINT_LEN );
if( !keyid || get_pubkey( pk, keyid ) )
{
goto failure; /* oops: no key for some reason */
}
{
size_t dummy;
fingerprint_from_pk( pk, fpr, &dummy );
}
}
else
pk = NULL;
if ( !(ctx = agent_open ()) )
goto failure;
{
char *line, *p;
int i, rc;
if (cacheid)
{
line = xmalloc (17 + 3*strlen (cacheid) + 2);
strcpy (line, "CLEAR_PASSPHRASE ");
p = line+17;
p = percent_plus_escape (p, cacheid);
}
else
{
line = xmalloc (17 + 40 + 2);
strcpy (line, "CLEAR_PASSPHRASE ");
p = line+17;
for (i=0; i < 20; i++, p +=2 )
sprintf (p, "%02X", fpr[i]);
}
*p = 0;
rc = assuan_transact (ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
xfree (line);
if (rc)
{
log_error (_("problem with the agent - disabling agent use\n"));
opt.use_agent = 0;
}
}
failure:
agent_close (ctx);
if (pk)
free_public_key( pk );
#endif /*ENABLE_AGENT_SUPPORT*/
}
/****************
* Ask for a passphrase and return that string.
*/
char *
ask_passphrase (const char *description,
const char *tryagain_text,
const char *promptid,
const char *prompt,
const char *cacheid, int *canceled)
{
char *pw = NULL;
if (canceled)
*canceled = 0;
if (!opt.batch && description)
tty_printf ("\n%s\n",description);
agent_died:
if ( opt.use_agent )
{
pw = agent_get_passphrase (NULL, 0, cacheid,
tryagain_text, description, prompt,
canceled );
if (!pw)
{
if (!opt.use_agent)
goto agent_died;
pw = NULL;
}
}
else if (fd_passwd)
{
pw = m_alloc_secure (strlen(fd_passwd)+1);
strcpy (pw, fd_passwd);
}
else if (opt.batch)
{
log_error(_("can't query passphrase in batch mode\n"));
pw = NULL;
}
else {
if (tryagain_text)
tty_printf(_("%s.\n"), tryagain_text);
pw = cpr_get_hidden(promptid? promptid : "passphrase.ask",
prompt?prompt : _("Enter passphrase: ") );
tty_kill_prompt();
}
if (!pw || !*pw)
write_status( STATUS_MISSING_PASSPHRASE );
return pw;
}
/* Return a new DEK object Using the string-to-key sepcifier S2K. Use
* KEYID and PUBKEY_ALGO to prompt the user.
MODE 0: Allow cached passphrase
1: Ignore cached passphrase
2: Ditto, but change the text to "repeat entry"
*/
DEK *
passphrase_to_dek( u32 *keyid, int pubkey_algo,
int cipher_algo, STRING2KEY *s2k, int mode,
const char *tryagain_text, int *canceled)
{
char *pw = NULL;
DEK *dek;
STRING2KEY help_s2k;
if (canceled)
*canceled = 0;
if( !s2k ) {
/* This is used for the old rfc1991 mode
* Note: This must match the code in encode.c with opt.rfc1991 set */
s2k = &help_s2k;
s2k->mode = 0;
s2k->hash_algo = S2K_DIGEST_ALGO;
}
/* If we do not have a passphrase available in NEXT_PW and status
information are request, we print them now. */
if( !next_pw && is_status_enabled() ) {
char buf[50];
if( keyid ) {
u32 used_kid[2];
char *us;
if( keyid[2] && keyid[3] ) {
used_kid[0] = keyid[2];
used_kid[1] = keyid[3];
}
else {
used_kid[0] = keyid[0];
used_kid[1] = keyid[1];
}
us = get_long_user_id_string( keyid );
write_status_text( STATUS_USERID_HINT, us );
m_free(us);
sprintf( buf, "%08lX%08lX %08lX%08lX %d 0",
(ulong)keyid[0], (ulong)keyid[1],
(ulong)used_kid[0], (ulong)used_kid[1],
pubkey_algo );
write_status_text( STATUS_NEED_PASSPHRASE, buf );
}
else {
sprintf( buf, "%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 = m_alloc_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);
m_free(p);
if( !get_pubkey( pk, keyid ) ) {
const char *s = pubkey_algo_to_string( 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 );
}
agent_died:
if( next_pw ) {
/* Simply return the passphrase we already have in NEXT_PW. */
pw = next_pw;
next_pw = NULL;
}
else if ( opt.use_agent ) {
/* Divert to the gpg-agent. */
pw = agent_get_passphrase ( keyid, mode == 2? 1: 0, NULL,
tryagain_text, NULL, NULL, canceled );
if (!pw)
{
if (!opt.use_agent)
goto agent_died;
pw = m_strdup ("");
}
if( *pw && mode == 2 ) {
char *pw2 = agent_get_passphrase ( keyid, 2, NULL, NULL, NULL,
NULL, canceled );
if (!pw2)
{
if (!opt.use_agent)
{
m_free (pw);
pw = NULL;
goto agent_died;
}
pw2 = m_strdup ("");
}
if( strcmp(pw, pw2) ) {
m_free(pw2);
m_free(pw);
return NULL;
}
m_free(pw2);
}
}
else if( fd_passwd ) {
/* Return the passphrase we have store in FD_PASSWD. */
pw = m_alloc_secure( strlen(fd_passwd)+1 );
strcpy( pw, fd_passwd );
}
else if( opt.batch )
{
log_error(_("can't query passphrase in batch mode\n"));
pw = m_strdup( "" ); /* return an empty passphrase */
}
else {
/* Read the passphrase from the tty or the command-fd. */
pw = cpr_get_hidden("passphrase.enter", _("Enter passphrase: ") );
tty_kill_prompt();
if( mode == 2 && !cpr_enabled() ) {
char *pw2 = cpr_get_hidden("passphrase.repeat",
_("Repeat passphrase: ") );
tty_kill_prompt();
if( strcmp(pw, pw2) ) {
m_free(pw2);
m_free(pw);
return NULL;
}
m_free(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 = m_alloc_secure_clear ( sizeof *dek );
dek->algo = cipher_algo;
if( !*pw && mode == 2 )
dek->keylen = 0;
else
hash_passphrase( dek, pw, s2k, mode==2 );
m_free(last_pw);
last_pw = pw;
return dek;
}
/****************
* Hash a passphrase using the supplied s2k. If create is true, create
* a new salt or what else must be filled into the s2k for a new key.
* always needs: dek->algo, s2k->mode, s2k->hash_algo.
*/
static void
hash_passphrase( DEK *dek, char *pw, STRING2KEY *s2k, int create )
{
MD_HANDLE md;
int pass, i;
int used = 0;
int pwlen = strlen(pw);
assert( s2k->hash_algo );
dek->keylen = cipher_get_keylen( dek->algo ) / 8;
if( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
BUG();
md = md_open( s2k->hash_algo, 1);
for(pass=0; used < dek->keylen ; pass++ ) {
if( pass ) {
md_reset(md);
for(i=0; i < pass; i++ ) /* preset the hash context */
md_putc(md, 0 );
}
if( s2k->mode == 1 || s2k->mode == 3 ) {
int len2 = pwlen + 8;
ulong count = len2;
if( create && !pass ) {
randomize_buffer(s2k->salt, 8, 1);
if( s2k->mode == 3 )
s2k->count = 96; /* 65536 iterations */
}
if( s2k->mode == 3 ) {
count = (16ul + (s2k->count & 15)) << ((s2k->count >> 4) + 6);
if( count < len2 )
count = len2;
}
/* a little bit complicated because we need a ulong for count */
while( count > len2 ) { /* maybe iterated+salted */
md_write( md, s2k->salt, 8 );
md_write( md, pw, pwlen );
count -= len2;
}
if( count < 8 )
md_write( md, s2k->salt, count );
else {
md_write( md, s2k->salt, 8 );
count -= 8;
md_write( md, pw, count );
}
}
else
md_write( md, pw, pwlen );
md_final( md );
i = md_digest_length( s2k->hash_algo );
if( i > dek->keylen - used )
i = dek->keylen - used;
memcpy( dek->key+used, md_read(md, s2k->hash_algo), i );
used += i;
}
md_close(md);
}
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