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/* call-agent.c - divert operations to the agent
* Copyright (C) 2001, 2002, 2003, 2006 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 3 of the License, or
* (at your option) any later version.
*
* GnuPG is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <config.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <time.h>
#include <assert.h>
#ifdef HAVE_LOCALE_H
#include <locale.h>
#endif
#include <assuan.h>
#include "gpg.h"
#include "util.h"
#include "membuf.h"
#include "options.h"
#include "i18n.h"
#include "asshelp.h"
#include "call-agent.h"
#ifndef DBG_ASSUAN
# define DBG_ASSUAN 1
#endif
static assuan_context_t agent_ctx = NULL;
struct cipher_parm_s
{
assuan_context_t ctx;
const char *ciphertext;
size_t ciphertextlen;
};
struct writekey_parm_s
{
assuan_context_t ctx;
const unsigned char *keydata;
size_t keydatalen;
};
struct genkey_parm_s
{
assuan_context_t ctx;
const char *sexp;
size_t sexplen;
};
/* Try to connect to the agent via socket or fork it off and work by
pipes. Handle the server's initial greeting */
static int
start_agent (void)
{
if (agent_ctx)
return 0; /* Fixme: We need a context for each thread or serialize
the access to the agent. */
return start_new_gpg_agent (&agent_ctx,
GPG_ERR_SOURCE_DEFAULT,
opt.homedir,
opt.agent_program,
opt.display, opt.ttyname, opt.ttytype,
opt.lc_ctype, opt.lc_messages,
opt.verbose, DBG_ASSUAN,
NULL, NULL);
}
/* Return a new malloced string by unescaping the string S. Escaping
is percent escaping and '+'/space mapping. A binary nul will
silently be replaced by a 0xFF. Function returns NULL to indicate
an out of memory status. */
static char *
unescape_status_string (const unsigned char *s)
{
char *buffer, *d;
buffer = d = xtrymalloc (strlen (s)+1);
if (!buffer)
return NULL;
while (*s)
{
if (*s == '%' && s[1] && s[2])
{
s++;
*d = xtoi_2 (s);
if (!*d)
*d = '\xff';
d++;
s += 2;
}
else if (*s == '+')
{
*d++ = ' ';
s++;
}
else
*d++ = *s++;
}
*d = 0;
return buffer;
}
/* 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. */
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;
}
/* Take a 20 byte hexencoded string and put it into the the provided
20 byte buffer FPR in binary format. */
static int
unhexify_fpr (const char *hexstr, unsigned char *fpr)
{
const char *s;
int n;
for (s=hexstr, n=0; hexdigitp (s); s++, n++)
;
if (*s || (n != 40))
return 0; /* no fingerprint (invalid or wrong length). */
n /= 2;
for (s=hexstr, n=0; *s; s += 2, n++)
fpr[n] = xtoi_2 (s);
return 1; /* okay */
}
/* Take the serial number from LINE and return it verbatim in a newly
allocated string. We make sure that only hex characters are
returned. */
static char *
store_serialno (const char *line)
{
const char *s;
char *p;
for (s=line; hexdigitp (s); s++)
;
p = xtrymalloc (s + 1 - line);
if (p)
{
memcpy (p, line, s-line);
p[s-line] = 0;
}
return p;
}
/* Release the card info structure INFO. */
void
agent_release_card_info (struct agent_card_info_s *info)
{
if (!info)
return;
xfree (info->serialno); info->serialno = NULL;
xfree (info->disp_name); info->disp_name = NULL;
xfree (info->disp_lang); info->disp_lang = NULL;
xfree (info->pubkey_url); info->pubkey_url = NULL;
xfree (info->login_data); info->login_data = NULL;
info->cafpr1valid = info->cafpr2valid = info->cafpr3valid = 0;
info->fpr1valid = info->fpr2valid = info->fpr3valid = 0;
}
static int
learn_status_cb (void *opaque, const char *line)
{
struct agent_card_info_s *parm = opaque;
const char *keyword = line;
int keywordlen;
int i;
for (keywordlen=0; *line && !spacep (line); line++, keywordlen++)
;
while (spacep (line))
line++;
if (keywordlen == 8 && !memcmp (keyword, "SERIALNO", keywordlen))
{
xfree (parm->serialno);
parm->serialno = store_serialno (line);
}
else if (keywordlen == 9 && !memcmp (keyword, "DISP-NAME", keywordlen))
{
xfree (parm->disp_name);
parm->disp_name = unescape_status_string (line);
}
else if (keywordlen == 9 && !memcmp (keyword, "DISP-LANG", keywordlen))
{
xfree (parm->disp_lang);
parm->disp_lang = unescape_status_string (line);
}
else if (keywordlen == 8 && !memcmp (keyword, "DISP-SEX", keywordlen))
{
parm->disp_sex = *line == '1'? 1 : *line == '2' ? 2: 0;
}
else if (keywordlen == 10 && !memcmp (keyword, "PUBKEY-URL", keywordlen))
{
xfree (parm->pubkey_url);
parm->pubkey_url = unescape_status_string (line);
}
else if (keywordlen == 10 && !memcmp (keyword, "LOGIN-DATA", keywordlen))
{
xfree (parm->login_data);
parm->login_data = unescape_status_string (line);
}
else if (keywordlen == 11 && !memcmp (keyword, "SIG-COUNTER", keywordlen))
{
parm->sig_counter = strtoul (line, NULL, 0);
}
else if (keywordlen == 10 && !memcmp (keyword, "CHV-STATUS", keywordlen))
{
char *p, *buf;
buf = p = unescape_status_string (line);
if (buf)
{
while (spacep (p))
p++;
parm->chv1_cached = atoi (p);
while (*p && !spacep (p))
p++;
while (spacep (p))
p++;
for (i=0; *p && i < 3; i++)
{
parm->chvmaxlen[i] = atoi (p);
while (*p && !spacep (p))
p++;
while (spacep (p))
p++;
}
for (i=0; *p && i < 3; i++)
{
parm->chvretry[i] = atoi (p);
while (*p && !spacep (p))
p++;
while (spacep (p))
p++;
}
xfree (buf);
}
}
else if (keywordlen == 7 && !memcmp (keyword, "KEY-FPR", keywordlen))
{
int no = atoi (line);
while (*line && !spacep (line))
line++;
while (spacep (line))
line++;
if (no == 1)
parm->fpr1valid = unhexify_fpr (line, parm->fpr1);
else if (no == 2)
parm->fpr2valid = unhexify_fpr (line, parm->fpr2);
else if (no == 3)
parm->fpr3valid = unhexify_fpr (line, parm->fpr3);
}
else if (keywordlen == 6 && !memcmp (keyword, "CA-FPR", keywordlen))
{
int no = atoi (line);
while (*line && !spacep (line))
line++;
while (spacep (line))
line++;
if (no == 1)
parm->cafpr1valid = unhexify_fpr (line, parm->cafpr1);
else if (no == 2)
parm->cafpr2valid = unhexify_fpr (line, parm->cafpr2);
else if (no == 3)
parm->cafpr3valid = unhexify_fpr (line, parm->cafpr3);
}
return 0;
}
/* Call the agent to learn about a smartcard */
int
agent_learn (struct agent_card_info_s *info)
{
int rc;
rc = start_agent ();
if (rc)
return rc;
memset (info, 0, sizeof *info);
rc = assuan_transact (agent_ctx, "LEARN --send",
NULL, NULL, NULL, NULL,
learn_status_cb, info);
return rc;
}
/* Call the agent to retrieve a data object. This function returns
the data in the same structure as used by the learn command. It is
allowed to update such a structure using this commmand. */
int
agent_scd_getattr (const char *name, struct agent_card_info_s *info)
{
int rc;
char line[ASSUAN_LINELENGTH];
if (!*name)
return gpg_error (GPG_ERR_INV_VALUE);
/* We assume that NAME does not need escaping. */
if (12 + strlen (name) > DIM(line)-1)
return gpg_error (GPG_ERR_TOO_LARGE);
stpcpy (stpcpy (line, "SCD GETATTR "), name);
rc = start_agent ();
if (rc)
return rc;
rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL,
learn_status_cb, info);
return rc;
}
/* Send an setattr command to the SCdaemon. SERIALNO is not actually
used here but required by gpg 1.4's implementation of this code in
cardglue.c. */
int
agent_scd_setattr (const char *name,
const unsigned char *value, size_t valuelen,
const char *serialno)
{
int rc;
char line[ASSUAN_LINELENGTH];
char *p;
if (!*name || !valuelen)
return gpg_error (GPG_ERR_INV_VALUE);
/* We assume that NAME does not need escaping. */
if (12 + strlen (name) > DIM(line)-1)
return gpg_error (GPG_ERR_TOO_LARGE);
p = stpcpy (stpcpy (line, "SCD SETATTR "), name);
*p++ = ' ';
for (; valuelen; value++, valuelen--)
{
if (p >= line + DIM(line)-5 )
return gpg_error (GPG_ERR_TOO_LARGE);
if (*value < ' ' || *value == '+' || *value == '%')
{
sprintf (p, "%%%02X", *value);
p += 3;
}
else if (*value == ' ')
*p++ = '+';
else
*p++ = *value;
}
*p = 0;
rc = start_agent ();
if (rc)
return rc;
rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
return rc;
}
/* Handle a KEYDATA inquiry. Note, we only send the data,
assuan_transact takes care of flushing and writing the end */
static assuan_error_t
inq_writekey_parms (void *opaque, const char *keyword)
{
struct writekey_parm_s *parm = opaque;
return assuan_send_data (parm->ctx, parm->keydata, parm->keydatalen);
}
/* Send a WRITEKEY command to the SCdaemon. */
int
agent_scd_writekey (int keyno, const char *serialno,
const unsigned char *keydata, size_t keydatalen)
{
int rc;
char line[ASSUAN_LINELENGTH];
struct writekey_parm_s parms;
rc = start_agent ();
if (rc)
return rc;
memset (&parms, 0, sizeof parms);
snprintf (line, DIM(line)-1, "SCD WRITEKEY --force OPENPGP.%d", keyno);
line[DIM(line)-1] = 0;
parms.ctx = agent_ctx;
parms.keydata = keydata;
parms.keydatalen = keydatalen;
rc = assuan_transact (agent_ctx, line, NULL, NULL,
inq_writekey_parms, &parms, NULL, NULL);
return rc;
}
/* Status callback for the SCD GENKEY command. */
static int
scd_genkey_cb (void *opaque, const char *line)
{
struct agent_card_genkey_s *parm = opaque;
const char *keyword = line;
int keywordlen;
gpg_error_t rc;
log_debug ("got status line `%s'\n", line);
for (keywordlen=0; *line && !spacep (line); line++, keywordlen++)
;
while (spacep (line))
line++;
if (keywordlen == 7 && !memcmp (keyword, "KEY-FPR", keywordlen))
{
parm->fprvalid = unhexify_fpr (line, parm->fpr);
}
if (keywordlen == 8 && !memcmp (keyword, "KEY-DATA", keywordlen))
{
gcry_mpi_t a;
const char *name = line;
while (*line && !spacep (line))
line++;
while (spacep (line))
line++;
rc = gcry_mpi_scan (&a, GCRYMPI_FMT_HEX, line, 0, NULL);
if (rc)
log_error ("error parsing received key data: %s\n", gpg_strerror (rc));
else if (*name == 'n' && spacep (name+1))
parm->n = a;
else if (*name == 'e' && spacep (name+1))
parm->e = a;
else
{
log_info ("unknown parameter name in received key data\n");
gcry_mpi_release (a);
}
}
else if (keywordlen == 14 && !memcmp (keyword,"KEY-CREATED-AT", keywordlen))
{
parm->created_at = (u32)strtoul (line, NULL, 10);
}
return 0;
}
/* Send a GENKEY command to the SCdaemon. SERIALNO is not used in
this implementation. */
int
agent_scd_genkey (struct agent_card_genkey_s *info, int keyno, int force,
const char *serialno)
{
int rc;
char line[ASSUAN_LINELENGTH];
rc = start_agent ();
if (rc)
return rc;
memset (info, 0, sizeof *info);
snprintf (line, DIM(line)-1, "SCD GENKEY %s%d",
force? "--force ":"", keyno);
line[DIM(line)-1] = 0;
memset (info, 0, sizeof *info);
rc = assuan_transact (agent_ctx, line,
NULL, NULL, NULL, NULL,
scd_genkey_cb, info);
return rc;
}
static int
membuf_data_cb (void *opaque, const void *buffer, size_t length)
{
membuf_t *data = opaque;
if (buffer)
put_membuf (data, buffer, length);
return 0;
}
/* Send a sign command to the scdaemon via gpg-agent's pass thru
mechanism. */
int
agent_scd_pksign (const char *serialno, int hashalgo,
const unsigned char *indata, size_t indatalen,
unsigned char **r_buf, size_t *r_buflen)
{
int rc, i;
char *p, line[ASSUAN_LINELENGTH];
membuf_t data;
size_t len;
/* Note, hashalgo is not yet used but hardwired to SHA1 in SCdaemon. */
*r_buf = NULL;
*r_buflen = 0;
rc = start_agent ();
if (rc)
return rc;
if (indatalen*2 + 50 > DIM(line))
return gpg_error (GPG_ERR_GENERAL);
sprintf (line, "SCD SETDATA ");
p = line + strlen (line);
for (i=0; i < indatalen ; i++, p += 2 )
sprintf (p, "%02X", indata[i]);
rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
if (rc)
return rc;
init_membuf (&data, 1024);
#if 0
if (!hashalgo) /* Temporary test hack. */
snprintf (line, DIM(line)-1, "SCD PKAUTH %s", serialno);
else
#endif
snprintf (line, DIM(line)-1, "SCD PKSIGN %s%s",
hashalgo == GCRY_MD_RMD160? "--hash=rmd160 " : "",
serialno);
line[DIM(line)-1] = 0;
rc = assuan_transact (agent_ctx, line, membuf_data_cb, &data,
NULL, NULL, NULL, NULL);
if (rc)
{
xfree (get_membuf (&data, &len));
return rc;
}
*r_buf = get_membuf (&data, r_buflen);
return 0;
}
/* Decrypt INDATA of length INDATALEN using the card identified by
SERIALNO. Return the plaintext in a nwly allocated buffer stored
at the address of R_BUF.
Note, we currently support only RSA or more exactly algorithms
taking one input data element. */
int
agent_scd_pkdecrypt (const char *serialno,
const unsigned char *indata, size_t indatalen,
unsigned char **r_buf, size_t *r_buflen)
{
int rc, i;
char *p, line[ASSUAN_LINELENGTH];
membuf_t data;
size_t len;
*r_buf = NULL;
rc = start_agent ();
if (rc)
return rc;
/* FIXME: use secure memory where appropriate */
if (indatalen*2 + 50 > DIM(line))
return gpg_error (GPG_ERR_GENERAL);
sprintf (line, "SCD SETDATA ");
p = line + strlen (line);
for (i=0; i < indatalen ; i++, p += 2 )
sprintf (p, "%02X", indata[i]);
rc = assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
if (rc)
return rc;
init_membuf (&data, 1024);
snprintf (line, DIM(line)-1, "SCD PKDECRYPT %s", serialno);
line[DIM(line)-1] = 0;
rc = assuan_transact (agent_ctx, line,
membuf_data_cb, &data,
NULL, NULL, NULL, NULL);
if (rc)
{
xfree (get_membuf (&data, &len));
return rc;
}
*r_buf = get_membuf (&data, r_buflen);
if (!*r_buf)
return gpg_error (GPG_ERR_ENOMEM);
return 0;
}
/* Change the PIN of an OpenPGP card or reset the retry counter.
CHVNO 1: Change the PIN
2: Same as 1
3: Change the admin PIN
101: Set a new PIN and reset the retry counter
102: Same as 101
SERIALNO is not used.
*/
int
agent_scd_change_pin (int chvno, const char *serialno)
{
int rc;
char line[ASSUAN_LINELENGTH];
const char *reset = "";
if (chvno >= 100)
reset = "--reset";
chvno %= 100;
rc = start_agent ();
if (rc)
return rc;
snprintf (line, DIM(line)-1, "SCD PASSWD %s %d", reset, chvno);
line[DIM(line)-1] = 0;
rc = assuan_transact (agent_ctx, line, NULL, NULL,
NULL, NULL, NULL, NULL);
return rc;
}
/* Perform a CHECKPIN operation. SERIALNO should be the serial
number of the card - optionally followed by the fingerprint;
however the fingerprint is ignored here. */
int
agent_scd_checkpin (const char *serialno)
{
int rc;
char line[ASSUAN_LINELENGTH];
rc = start_agent ();
if (rc)
return rc;
snprintf (line, DIM(line)-1, "SCD CHECKPIN %s", serialno);
line[DIM(line)-1] = 0;
return assuan_transact (agent_ctx, line,
NULL, NULL,
NULL, NULL, NULL, NULL);
}
/* Dummy function, only used by the gpg 1.4 implementation. */
void
agent_clear_pin_cache (const char *sn)
{
}
/* Note: All strings shall be UTF-8. On success the caler needs to
free the string stored at R_PASSPHRASE. On error NULL will be
stored at R_PASSPHRASE and an appropriate fpf error code
returned. */
gpg_error_t
agent_get_passphrase (const char *cache_id,
const char *err_msg,
const char *prompt,
const char *desc_msg,
char **r_passphrase)
{
int rc;
char *line, *p;
char cmd[] = "GET_PASSPHRASE --data -- ";
membuf_t data;
*r_passphrase = NULL;
rc = start_agent ();
if (rc)
return rc;
/* We allocate 3 times the needed space for the texts so that
there is enough space for escaping. */
line = xtrymalloc ( strlen (cmd) + 1
+ (cache_id? 3*strlen (cache_id): 1) + 1
+ (err_msg? 3*strlen (err_msg): 1) + 1
+ (prompt? 3*strlen (prompt): 1) + 1
+ (desc_msg? 3*strlen (desc_msg): 1) + 1
+ 1);
if (!line)
return gpg_error_from_syserror ();
p = stpcpy (line, cmd);
if (cache_id && *cache_id)
p = percent_plus_escape (p, cache_id);
else
*p++ = 'X';
*p++ = ' ';
if (err_msg && *err_msg)
p = percent_plus_escape (p, err_msg);
else
*p++ = 'X';
*p++ = ' ';
if (prompt && *prompt)
p = percent_plus_escape (p, prompt);
else
*p++ = 'X';
*p++ = ' ';
if (desc_msg && *desc_msg)
p = percent_plus_escape (p, desc_msg);
else
*p++ = 'X';
*p = 0;
init_membuf_secure (&data, 64);
rc = assuan_transact (agent_ctx, line,
membuf_data_cb, &data, NULL, NULL, NULL, NULL);
if (rc)
xfree (get_membuf (&data, NULL));
else
{
put_membuf (&data, "", 1);
*r_passphrase = get_membuf (&data, NULL);
if (!*r_passphrase)
rc = gpg_error_from_syserror ();
}
xfree (line);
return rc;
}
gpg_error_t
agent_clear_passphrase (const char *cache_id)
{
int rc;
char line[ASSUAN_LINELENGTH];
if (!cache_id || !*cache_id)
return 0;
rc = start_agent ();
if (rc)
return rc;
snprintf (line, DIM(line)-1, "CLEAR_PASSPHRASE %s", cache_id);
line[DIM(line)-1] = 0;
return assuan_transact (agent_ctx, line, NULL, NULL, NULL, NULL, NULL, NULL);
}

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