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gnupg/g10/passphrase.c
Marcus Brinkmann 9d864ebef7 2004-08-18 Marcus Brinkmann <marcus@g10code.de> 
* passphrase.c (agent_get_passphrase):
2004-08-18 00:03:07 +00:00

1240 lines
32 KiB
C
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/* passphrase.c - Get a passphrase
* Copyright (C) 1998,1999,2000,2001,2002,2003 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) || defined (__CYGWIN32__)
# include <windows.h>
#endif
#include <errno.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#ifdef HAVE_LANGINFO_CODESET
#include <langinfo.h>
#endif
#include "gpg.h"
#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"
enum gpga_protocol_codes {
/* Request codes */
GPGA_PROT_GET_VERSION = 1,
GPGA_PROT_GET_PASSPHRASE = 2,
GPGA_PROT_CLEAR_PASSPHRASE= 3,
GPGA_PROT_SHUTDOWN = 4,
GPGA_PROT_FLUSH = 5,
/* Reply codes */
GPGA_PROT_REPLY_BASE = 0x10000,
GPGA_PROT_OKAY = 0x10001,
GPGA_PROT_GOT_PASSPHRASE = 0x10002,
/* Error codes */
GPGA_PROT_ERROR_BASE = 0x20000,
GPGA_PROT_PROTOCOL_ERROR = 0x20001,
GPGA_PROT_INVALID_REQUEST= 0x20002,
GPGA_PROT_CANCELED = 0x20003,
GPGA_PROT_NO_PASSPHRASE = 0x20004,
GPGA_PROT_BAD_PASSPHRASE = 0x20005,
GPGA_PROT_INVALID_DATA = 0x20006,
GPGA_PROT_NOT_IMPLEMENTED= 0x20007,
GPGA_PROT_UI_PROBLEM = 0x20008
};
#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 )
{
xfree (next_pw);
next_pw = NULL;
if( s ) {
next_pw = gcry_xmalloc_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 = gcry_xmalloc_secure ( len );
if( pw2 )
memcpy(pw, pw2, i );
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" );
xfree ( fd_passwd );
fd_passwd = pw;
}
static int
writen ( int fd, const void *buf, size_t nbytes )
{
#if defined (_WIN32)
DWORD nwritten, nleft = nbytes;
while (nleft > 0) {
if ( !WriteFile( (HANDLE)write_fd, buf, nleft, &nwritten, NULL) ) {
log_error("write failed: ec=%d\n", (int)GetLastError());
return -1;
}
/*log_info("** WriteFile fd=%d nytes=%d nwritten=%d\n",
write_fd, nbytes, (int)nwritten);*/
Sleep(100);
nleft -= nwritten;
buf = (const BYTE *)buf + nwritten;
}
#elif defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
/* not implemented */
#else
size_t nleft = nbytes;
int nwritten;
while( nleft > 0 ) {
nwritten = write( fd, buf, nleft );
if( nwritten < 0 ) {
if ( errno == EINTR )
nwritten = 0;
else {
log_error ( "write() failed: %s\n", strerror (errno) );
return -1;
}
}
nleft -= nwritten;
buf = (const char*)buf + nwritten;
}
#endif
return 0;
}
static int
readn ( int fd, void *buf, size_t buflen, size_t *ret_nread )
{
#if defined (_WIN32)
DWORD nread, nleft = buflen;
while (nleft > 0) {
if ( !ReadFile( (HANDLE)read_fd, buf, nleft, &nread, NULL) ) {
log_error("read() error: ec=%d\n", (int)GetLastError());
return -1;
}
if (!nread || GetLastError() == ERROR_BROKEN_PIPE)
break;
/*log_info("** ReadFile fd=%d buflen=%d nread=%d\n",
read_fd, buflen, (int)nread);*/
Sleep(100);
nleft -= nread;
buf = (BYTE *)buf + nread;
}
if (ret_nread)
*ret_nread = buflen - nleft;
#elif defined(HAVE_DOSISH_SYSTEM) || defined(__riscos__)
/* not implemented */
#else
size_t nleft = buflen;
int nread;
char *p;
p = buf;
while( nleft > 0 ) {
nread = read ( fd, buf, nleft );
if( nread < 0 ) {
if (nread == EINTR)
nread = 0;
else {
log_error ( "read() error: %s\n", strerror (errno) );
return -1;
}
}
else if( !nread )
break; /* EOF */
nleft -= nread;
buf = (char*)buf + nread;
}
if( ret_nread )
*ret_nread = buflen - nleft;
#endif
return 0;
}
/* read an entire line */
static int
readline (int fd, char *buf, size_t buflen)
{
size_t nleft = buflen;
char *p;
int nread = 0;
while (nleft > 0)
{
int n = read (fd, buf, nleft);
if (n < 0)
{
if (errno == EINTR)
continue;
return -1; /* read error */
}
else if (!n)
{
return -1; /* incomplete line */
}
p = buf;
nleft -= n;
buf += n;
nread += n;
for (; n && *p != '\n'; n--, p++)
;
if (n)
{
break; /* at least one full line available - that's enough.
This function is just a temporary hack until we use
the assuna lib in gpg. So it is okay to forget
about pending bytes */
}
}
return nread;
}
#if !defined (__riscos__)
#if !defined (_WIN32)
/* For the new Assuan protocol we may have to send options */
static int
agent_send_option (int fd, const char *name, const char *value)
{
char buf[200];
int nread;
char *line;
int i;
line = xmalloc (7 + strlen (name) + 1 + strlen (value) + 2);
strcpy (stpcpy (stpcpy (stpcpy (
stpcpy (line, "OPTION "), name), "="), value), "\n");
i = writen (fd, line, strlen (line));
xfree (line);
if (i)
return -1;
/* get response */
nread = readline (fd, buf, DIM(buf)-1);
if (nread < 3)
return -1;
if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n'))
return 0; /* okay */
return -1;
}
static int
agent_send_all_options (int fd)
{
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 (fd, "display",
opt.display ? opt.display : dft_display))
return -1;
}
if (!opt.ttyname)
{
dft_ttyname = getenv ("GPG_TTY");
if ((!dft_ttyname || !*dft_ttyname) && tty_get_ttyname ())
dft_ttyname = tty_get_ttyname ();
}
if (opt.ttyname || dft_ttyname)
{
if (agent_send_option (fd, "ttyname",
opt.ttyname ? opt.ttyname : dft_ttyname))
return -1;
}
dft_ttytype = getenv ("TERM");
if (opt.ttytype || (dft_ttyname && dft_ttytype))
{
if (agent_send_option (fd, "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 = xstrdup (old_lc);
dft_lc = setlocale (LC_CTYPE, "");
#endif
if (opt.lc_ctype || (dft_ttyname && dft_lc))
{
rc = agent_send_option (fd, "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);
xfree (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 = xstrdup (old_lc);
dft_lc = setlocale (LC_MESSAGES, "");
#endif
if (opt.lc_messages || (dft_ttyname && dft_lc))
{
rc = agent_send_option (fd, "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);
xfree (old_lc);
}
#endif
return rc;
}
#endif /*!_WIN32*/
/*
* Open a connection to the agent and send the magic string
* Returns: -1 on error or an filedescriptor for urther processing
*/
static int
agent_open (int *ret_prot)
{
#if defined (_WIN32)
int fd;
char *infostr, *p;
HANDLE h;
char pidstr[128];
*ret_prot = 0;
if ( !(infostr = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
"agentPID"))
|| *infostr == '0') {
log_error( _("gpg-agent is not available in this session\n"));
return -1;
}
free(infostr);
sprintf(pidstr, "%u", (unsigned int)GetCurrentProcessId());
if (write_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
"agentCID", pidstr)) {
log_error( _("can't set client pid for the agent\n") );
return -1;
}
h = OpenEvent(EVENT_ALL_ACCESS, FALSE, "gpg_agent");
SetEvent(h);
Sleep(50); /* some time for the server */
if ( !(p = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
"agentReadFD")) ) {
log_error( _("can't get server read FD for the agent\n") );
return -1;
}
read_fd = atol(p);
free(p);
if ( !(p = read_w32_registry_string(NULL, "Software\\GNU\\GnuPG",
"agentWriteFD")) ) {
log_error ( _("can't get server write FD for the agent\n") );
return -1;
}
write_fd = atol(p);
free(p);
fd = 0;
if ( writen ( fd, "GPGA\0\0\0\x01", 8 ) ) {
fd = -1;
}
#else /* Posix */
int fd;
char *infostr, *p;
struct sockaddr_un client_addr;
size_t len;
int prot;
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 -1;
}
infostr = xstrdup ( infostr );
}
if ( !(p = strchr ( infostr, ':')) || p == infostr
|| (p-infostr)+1 >= sizeof client_addr.sun_path ) {
log_error( _("malformed GPG_AGENT_INFO environment variable\n"));
xfree (infostr );
opt.use_agent = 0;
return -1;
}
*p++ = 0;
/* See whether this is the new gpg-agent using the Assuna protocl.
This agent identifies itself by have an info string with a
version number in the 3rd field. */
while (*p && *p != ':')
p++;
prot = *p? atoi (p+1) : 0;
if ( prot < 0 || prot > 1) {
log_error (_("gpg-agent protocol version %d is not supported\n"),prot);
xfree (infostr );
opt.use_agent = 0;
return -1;
}
*ret_prot = prot;
if( (fd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1 ) {
log_error ("can't create socket: %s\n", strerror(errno) );
xfree (infostr );
opt.use_agent = 0;
return -1;
}
memset( &client_addr, 0, sizeof client_addr );
client_addr.sun_family = AF_UNIX;
strcpy( client_addr.sun_path, infostr );
len = offsetof (struct sockaddr_un, sun_path)
+ strlen(client_addr.sun_path) + 1;
if( connect( fd, (struct sockaddr*)&client_addr, len ) == -1 ) {
log_error ( _("can't connect to `%s': %s\n"),
infostr, strerror (errno) );
xfree (infostr );
close (fd );
opt.use_agent = 0;
return -1;
}
xfree (infostr);
if (!prot) {
if ( writen ( fd, "GPGA\0\0\0\x01", 8 ) ) {
close (fd);
fd = -1;
}
}
else { /* assuan based gpg-agent */
char line[200];
int nread;
nread = readline (fd, line, DIM(line));
if (nread < 3 || !(line[0] == 'O' && line[1] == 'K'
&& (line[2] == '\n' || line[2] == ' ')) ) {
log_error ( _("communication problem with gpg-agent\n"));
close (fd );
opt.use_agent = 0;
return -1;
}
if (agent_send_all_options (fd)) {
log_error (_("problem with the agent - disabling agent use\n"));
close (fd);
opt.use_agent = 0;
return -1;
}
}
#endif
return fd;
}
static void
agent_close ( int fd )
{
#if defined (_WIN32)
HANDLE h = OpenEvent(EVENT_ALL_ACCESS, FALSE, "gpg_agent");
ResetEvent(h);
#else
close (fd);
#endif
}
#endif /* !__riscos__ */
/*
* 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.
*/
static char *
agent_get_passphrase ( u32 *keyid, int mode, const char *tryagain_text,
int *canceled)
{
#if defined(__riscos__)
return NULL;
#else
size_t n;
char *atext = NULL;
char buf[50];
int fd = -1;
int nread;
u32 reply;
char *pw = NULL;
PKT_public_key *pk = xcalloc (1, sizeof *pk );
byte fpr[MAX_FINGERPRINT_LEN];
int have_fpr = 0;
int prot;
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 ) )
{
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_GT, 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 = xstrdup (orig_codeset);
if (!bind_textdomain_codeset (PACKAGE_GT, "utf-8"))
orig_codeset = NULL;
}
#endif
if ( (fd = agent_open (&prot)) == -1 )
goto failure;
if ( !mode && pk && keyid )
{
char *uid;
size_t uidlen;
const char *algo_name = gcry_pk_algo_name ( pk->pubkey_algo );
const char *timestr;
char *maink;
if ( !algo_name )
algo_name = "?";
if( keyid[2] && keyid[3] && keyid[0] != keyid[2]
&& keyid[1] != keyid[3] )
maink = xasprintf ( _(" (main key ID %08lX)"), (ulong)keyid[3] );
else
maink = NULL;
uid = get_user_id ( keyid, &uidlen );
timestr = strtimestamp (pk->timestamp);
atext = xasprintf (
_("You need a passphrase to unlock the"
" secret key for user:\n"
"\"%.*s\"\n"
"%u-bit %s key, ID %08lX, created %s%s\n" ),
uidlen, uid,
nbits_from_pk (pk), algo_name, (ulong)keyid[1], timestr,
maink?maink:"" );
xfree (uid);
xfree (maink);
{
size_t dummy;
fingerprint_from_pk( pk, fpr, &dummy );
have_fpr = 1;
}
}
else if (mode == 2 )
atext = xstrdup ( _("Repeat passphrase\n") );
else
atext = xstrdup ( _("Enter passphrase\n") );
if (!prot)
{ /* old style protocol */
n = 4 + 20 + strlen (atext);
u32tobuf (buf, n );
u32tobuf (buf+4, GPGA_PROT_GET_PASSPHRASE );
memcpy (buf+8, fpr, 20 );
if ( writen ( fd, buf, 28 ) || writen ( fd, atext, strlen (atext) ) )
goto failure;
xfree (atext); atext = NULL;
/* get response */
if ( readn ( fd, buf, 12, &nread ) )
goto failure;
if ( nread < 8 )
{
log_error ( "response from agent too short\n" );
goto failure;
}
n = buftou32 ( buf );
reply = buftou32 ( buf + 4 );
if ( reply == GPGA_PROT_GOT_PASSPHRASE )
{
size_t pwlen;
size_t nn;
if ( nread < 12 || n < 8 )
{
log_error ( "response from agent too short\n" );
goto failure;
}
pwlen = buftou32 ( buf + 8 );
nread -= 12;
n -= 8;
if ( pwlen > n || n > 1000 )
{
log_error (_("passphrase too long\n"));
/* or protocol error */
goto failure;
}
/* we read the whole block in one chunk to give no hints
* on how long the passhrase actually is - this wastes some bytes
* but because we already have this padding we should not loosen
* this by issuing 2 read calls */
pw = xmalloc_secure ( n+1 );
if ( readn ( fd, pw, n, &nn ) )
goto failure;
if ( n != nn )
{
log_error (_("invalid response from agent\n"));
goto failure;
}
pw[pwlen] = 0; /* make a C String */
agent_close (fd);
free_public_key( pk );
#ifdef ENABLE_NLS
if (orig_codeset)
bind_textdomain_codeset (PACKAGE_GT, orig_codeset);
#endif
xfree (orig_codeset);
return pw;
}
else if ( reply == GPGA_PROT_CANCELED )
{
log_info ( _("cancelled by user\n") );
if (canceled)
*canceled = 1;
}
else
log_error ( _("problem with the agent: agent returns 0x%lx\n"),
(ulong)reply );
}
else
{ /* The new Assuan protocol */
char *line, *p;
const unsigned char *s;
int i;
if (!tryagain_text)
tryagain_text = "X";
else
tryagain_text = _(tryagain_text);
/* We allocate 2 time the needed space for atext so that there
is enough space for escaping */
line = xmalloc (15 + 46
+ 3*strlen (tryagain_text) + 3*strlen (atext) + 2);
strcpy (line, "GET_PASSPHRASE ");
p = line+15;
if (!mode && have_fpr)
{
for (i=0; i < 20; i++, p +=2 )
sprintf (p, "%02X", fpr[i]);
}
else
*p++ = 'X'; /* no caching */
*p++ = ' ';
for (i=0, s=tryagain_text; *s; s++)
{
if (*s < ' ' || *s == '+')
{
sprintf (p, "%%%02X", *s);
p += 3;
}
else if (*s == ' ')
*p++ = '+';
else
*p++ = *s;
}
*p++ = ' ';
*p++ = 'X'; /* Use the standard prompt */
*p++ = ' ';
/* copy description */
for (i=0, s= atext; *s; s++)
{
if (*s < ' ' || *s == '+')
{
sprintf (p, "%%%02X", *s);
p += 3;
}
else if (*s == ' ')
*p++ = '+';
else
*p++ = *s;
}
*p++ = '\n';
i = writen (fd, line, p - line);
xfree (line);
if (i)
goto failure;
xfree (atext); atext = NULL;
/* get response */
pw = xmalloc_secure (500);
nread = readline (fd, pw, 499);
if (nread < 3)
goto failure;
if (pw[0] == 'O' && pw[1] == 'K' && pw[2] == ' ')
{ /* we got a passphrase - convert it back from hex */
size_t pwlen = 0;
for (i=3; i < nread && hexdigitp (pw+i); i+=2)
pw[pwlen++] = xtoi_2 (pw+i);
pw[pwlen] = 0; /* make a C String */
agent_close (fd);
free_public_key( pk );
#ifdef ENABLE_NLS
if (orig_codeset)
bind_textdomain_codeset (PACKAGE_GT, orig_codeset);
#endif
xfree (orig_codeset);
return pw;
}
else if (nread > 4 && !memcmp (pw, "ERR ", 4)
&& (0xffff & strtoul (&pw[4], NULL, 0)) == 99)
{
/* 99 is GPG_ERR_CANCELED. FIXME: Check tail and overflow,
and use gpg-error. */
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_GT, orig_codeset);
#endif
xfree (atext);
if ( fd != -1 )
agent_close (fd);
xfree (pw );
free_public_key( pk );
return NULL;
#endif /* Posix or W32 */
}
/*
* Clear the cached passphrase
*/
void
passphrase_clear_cache ( u32 *keyid, int algo )
{
#if defined(__riscos__)
return ;
#else
size_t n;
char buf[200];
int fd = -1;
size_t nread;
u32 reply;
PKT_public_key *pk;
byte fpr[MAX_FINGERPRINT_LEN];
int prot;
#if MAX_FINGERPRINT_LEN < 20
#error agent needs a 20 byte fingerprint
#endif
if (!opt.use_agent)
return;
pk = xcalloc (1, sizeof *pk );
memset (fpr, 0, MAX_FINGERPRINT_LEN );
if( !keyid || get_pubkey( pk, keyid ) )
{
log_debug ("oops, no key in passphrase_clear_cache\n");
goto failure; /* oops: no key for some reason */
}
{
size_t dummy;
fingerprint_from_pk( pk, fpr, &dummy );
}
if ( (fd = agent_open (&prot)) == -1 )
goto failure;
if (!prot)
{
n = 4 + 20;
u32tobuf (buf, n );
u32tobuf (buf+4, GPGA_PROT_CLEAR_PASSPHRASE );
memcpy (buf+8, fpr, 20 );
if ( writen ( fd, buf, 28 ) )
goto failure;
/* get response */
if ( readn ( fd, buf, 8, &nread ) )
goto failure;
if ( nread < 8 ) {
log_error ( "response from agent too short\n" );
goto failure;
}
reply = buftou32 ( buf + 4 );
if ( reply != GPGA_PROT_OKAY && reply != GPGA_PROT_NO_PASSPHRASE )
{
log_error ( _("problem with the agent: agent returns 0x%lx\n"),
(ulong)reply );
}
}
else
{ /* The assuan protocol */
char *line, *p;
int i;
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++ = '\n';
i = writen (fd, line, p - line);
xfree (line);
if (i)
goto failure;
/* get response */
nread = readline (fd, buf, DIM(buf)-1);
if (nread < 3)
goto failure;
if (buf[0] == 'O' && buf[1] == 'K' && (buf[2] == ' ' || buf[2] == '\n'))
;
else
{
log_error (_("problem with the agent - disabling agent use\n"));
opt.use_agent = 0;
}
}
failure:
if (fd != -1)
agent_close (fd);
free_public_key( pk );
#endif /* Posix or W32 */
}
/****************
* Get a passphrase for the secret key with KEYID, display TEXT
* if the user needs to enter the passphrase.
* mode 0 = standard, 1 = same but don't show key info,
* 2 = create new passphrase
* Returns: a DEK with a session key; caller must free
* or NULL if the passphrase was not correctly repeated.
* (only for mode 2)
* a dek->keylen of 0 means: no passphrase entered.
* (only for mode 2)
*
* pubkey_algo is only informational. Note that TRYAGAIN_TEXT must
* not be translated as this is done within this function (required to
* switch to utf-8 when the agent is in use). If CANCELED is not
* NULL, it is set to 1 if the user choosed to cancel the operation,
* otherwise it will be set to 0.
*/
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 = opt.s2k_digest_algo;
}
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 );
xfree (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( keyid && !opt.batch && !next_pw && mode!=1 ) {
PKT_public_key *pk = xcalloc (1, sizeof *pk );
size_t n;
char *p;
tty_printf(_("\nYou need a passphrase to unlock the secret key for\n"
"user: \"") );
p = get_user_id( keyid, &n );
tty_print_utf8_string( p, n );
xfree (p);
tty_printf("\"\n");
if( !get_pubkey( pk, keyid ) ) {
const char *s = gcry_pk_algo_name ( pk->pubkey_algo );
tty_printf( _("%u-bit %s key, ID %08lX, created %s"),
nbits_from_pk( pk ), s?s:"?", (ulong)keyid[1],
strtimestamp(pk->timestamp) );
if( keyid[2] && keyid[3] && keyid[0] != keyid[2]
&& keyid[1] != keyid[3] )
tty_printf( _(" (main key ID %08lX)"), (ulong)keyid[3] );
tty_printf("\n");
}
tty_printf("\n");
free_public_key( pk );
}
agent_died:
if( next_pw ) {
pw = next_pw;
next_pw = NULL;
}
else if ( opt.use_agent ) {
pw = agent_get_passphrase ( keyid, mode == 2? 1: 0,
tryagain_text, canceled );
if (!pw)
{
if (!opt.use_agent)
goto agent_died;
pw = xstrdup ("");
}
if( *pw && mode == 2 ) {
char *pw2 = agent_get_passphrase ( keyid, 2, NULL, canceled );
if (!pw2)
{
if (!opt.use_agent)
{
xfree (pw);
pw = NULL;
goto agent_died;
}
pw2 = xstrdup ("");
}
if( strcmp(pw, pw2) ) {
xfree (pw2);
xfree (pw);
return NULL;
}
xfree (pw2);
}
}
else if( fd_passwd ) {
pw = xmalloc_secure ( strlen(fd_passwd)+1 );
strcpy( pw, fd_passwd );
}
else if( opt.batch ) {
log_error(_("can't query password in batchmode\n"));
pw = xstrdup ( "" ); /* return an empty passphrase */
}
else {
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) ) {
xfree (pw2);
xfree (pw);
return NULL;
}
xfree (pw2);
}
}
if( !pw || !*pw )
write_status( STATUS_MISSING_PASSPHRASE );
dek = xcalloc_secure (1, 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;
}
/****************
* 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 = gcry_cipher_get_algo_keylen (dek->algo);
if( !(dek->keylen > 0 && dek->keylen <= DIM(dek->key)) )
BUG();
gcry_md_open (&md, s2k->hash_algo, 1);
for(pass=0; used < dek->keylen ; pass++ ) {
if( pass ) {
gcry_md_reset(md);
for(i=0; i < pass; i++ ) /* preset the hash context */
gcry_md_putc (md, 0 );
}
if( s2k->mode == 1 || s2k->mode == 3 ) {
int len2 = pwlen + 8;
ulong count = len2;
if( create && !pass ) {
gcry_randomize(s2k->salt, 8, GCRY_STRONG_RANDOM );
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 */
gcry_md_write( md, s2k->salt, 8 );
gcry_md_write( md, pw, pwlen );
count -= len2;
}
if( count < 8 )
gcry_md_write( md, s2k->salt, count );
else {
gcry_md_write( md, s2k->salt, 8 );
count -= 8;
gcry_md_write( md, pw, count );
}
}
else
gcry_md_write( md, pw, pwlen );
gcry_md_final ( md );
i = gcry_md_get_algo_dlen (s2k->hash_algo);
if( i > dek->keylen - used )
i = dek->keylen - used;
memcpy( dek->key+used, gcry_md_read (md, s2k->hash_algo), i );
used += i;
}
gcry_md_close (md);
}
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