/* command.c - SCdaemon command handler
* Copyright (C) 2001, 2002 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 <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <unistd.h>
#include <ksba.h>
#include "scdaemon.h"
#include "../assuan/assuan.h"
/* maximum length aloowed as a PIN; used for INQUIRE NEEDPIN */
#define MAXLEN_PIN 100
#define set_error(e,t) assuan_set_error (ctx, ASSUAN_ ## e, (t))
/* Data used to associate an Assuan context with local server data */
struct server_local_s {
ASSUAN_CONTEXT assuan_ctx;
};
/* Check whether the option NAME appears in LINE */
static int
has_option (const char *line, const char *name)
{
const char *s;
int n = strlen (name);
s = strstr (line, name);
return (s && (s == line || spacep (s-1)) && (!s[n] || spacep (s+n)));
}
/* Note, that this reset_notify is also used for cleanup purposes. */
static void
reset_notify (ASSUAN_CONTEXT ctx)
{
CTRL ctrl = assuan_get_pointer (ctx);
if (ctrl->card_ctx)
{
card_close (ctrl->card_ctx);
ctrl->card_ctx = NULL;
xfree (ctrl->in_data.value);
ctrl->in_data.value = NULL;
}
}
static int
option_handler (ASSUAN_CONTEXT ctx, const char *key, const char *value)
{
return 0;
}
/* If the card has not yet been opened, do it. Note that this
function returns an Assuan error, so don't map the error a second
time */
static AssuanError
open_card (CTRL ctrl)
{
if (!ctrl->card_ctx)
{
int rc = card_open (&ctrl->card_ctx);
if (rc)
return map_to_assuan_status (rc);
}
return 0;
}
/* SERIALNO
Return the serial number of the card using a status reponse. This
functon should be used to check for the presence of a card.
This function is special in that it can be used to reset the card.
Most other functions will return an error when a card change has
been detected and the use of this function is therefore required.
Background: We want to keep the client clear of handling card
changes between operations; i.e. the client can assume that all
operations are doneon the same card unless he call this function.
*/
static int
cmd_serialno (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc = 0;
char *serial_and_stamp;
char *serial;
time_t stamp;
if ((rc = open_card (ctrl)))
return rc;
rc = card_get_serial_and_stamp (ctrl->card_ctx, &serial, &stamp);
if (rc)
return map_to_assuan_status (rc);
rc = asprintf (&serial_and_stamp, "%s %lu", serial, (unsigned long)stamp);
xfree (serial);
if (rc < 0)
return ASSUAN_Out_Of_Core;
rc = 0;
assuan_write_status (ctx, "SERIALNO", serial_and_stamp);
free (serial_and_stamp);
return 0;
}
/* LEARN [--force]
Learn all useful information of the currently inserted card. When
used without the force options, the command might do an INQUIRE
like this:
INQUIRE KNOWNCARDP <hexstring_with_serialNumber> <timestamp>
The client should just send an "END" if the processing should go on
or a "CANCEL" to force the function to terminate with a Cancel
error message. The response of this command is a list of status
lines formatted as this:
S KEYPAIRINFO <hexstring_with_keygrip> <hexstring_with_id>
If there is no certificate yet stored on the card a single "X" is
returned as the keygrip. In addition to the keypair info, information
about all certificates stored on the card is also returned:
S CERTINFO <certtype> <hexstring_with_id>
Where CERTINFO is a number indicating the type of certificate:
0 := Unknown
100 := Regular X.509 cert
101 := Trusted X.509 cert
102 := Useful X.509 cert
*/
static int
cmd_learn (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc = 0;
int idx;
if ((rc = open_card (ctrl)))
return rc;
/* Unless the force option is used we try a shortcut by identifying
the card using a serial number and inquiring the client with
that. The client may choose to cancel the operation if he already
knows about this card */
{
char *serial_and_stamp;
char *serial;
time_t stamp;
rc = card_get_serial_and_stamp (ctrl->card_ctx, &serial, &stamp);
if (rc)
return map_to_assuan_status (rc);
rc = asprintf (&serial_and_stamp, "%s %lu", serial, (unsigned long)stamp);
xfree (serial);
if (rc < 0)
return ASSUAN_Out_Of_Core;
rc = 0;
assuan_write_status (ctx, "SERIALNO", serial_and_stamp);
if (!has_option (line, "--force"))
{
char *command;
rc = asprintf (&command, "KNOWNCARDP %s", serial_and_stamp);
if (rc < 0)
{
free (serial_and_stamp);
return ASSUAN_Out_Of_Core;
}
rc = 0;
rc = assuan_inquire (ctx, command, NULL, NULL, 0);
free (command); /* (must use standard free here) */
if (rc)
{
if (rc != ASSUAN_Canceled)
log_error ("inquire KNOWNCARDP failed: %s\n",
assuan_strerror (rc));
free (serial_and_stamp);
return rc;
}
/* not canceled, so we have to proceeed */
}
free (serial_and_stamp);
}
/* Return information about the certificates. */
for (idx=0; !rc; idx++)
{
char *certid;
int certtype;
rc = card_enum_certs (ctrl->card_ctx, idx, &certid, &certtype);
if (!rc)
{
char *buf;
buf = xtrymalloc (40 + 1 + strlen (certid) + 1);
if (!buf)
rc = GNUPG_Out_Of_Core;
else
{
sprintf (buf, "%d %s", certtype, certid);
assuan_write_status (ctx, "CERTINFO", buf);
xfree (buf);
}
}
xfree (certid);
}
if (rc == -1)
rc = 0;
/* Return information about the keys. */
for (idx=0; !rc; idx++)
{
unsigned char keygrip[20];
char *keyid;
int no_cert = 0;
rc = card_enum_keypairs (ctrl->card_ctx, idx, keygrip, &keyid);
if (rc == GNUPG_Missing_Certificate && keyid)
{
/* this does happen with an incomplete personalized
card; i.e. during the time we have stored the key on the
card but not stored the certificate; probably becuase it
has not yet been received back from the CA. Note that we
must release KEYID in this case. */
rc = 0;
no_cert = 1;
}
if (!rc)
{
char *buf, *p;
buf = p = xtrymalloc (40 + 1 + strlen (keyid) + 1);
if (!buf)
rc = GNUPG_Out_Of_Core;
else
{
int i;
if (no_cert)
*p++ = 'X';
else
{
for (i=0; i < 20; i++, p += 2)
sprintf (p, "%02X", keygrip[i]);
}
*p++ = ' ';
strcpy (p, keyid);
assuan_write_status (ctx, "KEYPAIRINFO", buf);
xfree (buf);
}
}
xfree (keyid);
}
if (rc == -1)
rc = 0;
return map_to_assuan_status (rc);
}
/* READCERT <hexified_certid>
*/
static int
cmd_readcert (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc;
unsigned char *cert;
size_t ncert;
if ((rc = open_card (ctrl)))
return rc;
rc = card_read_cert (ctrl->card_ctx, line, &cert, &ncert);
if (rc)
{
log_error ("card_read_cert failed: %s\n", gnupg_strerror (rc));
}
if (!rc)
{
rc = assuan_send_data (ctx, cert, ncert);
xfree (cert);
if (rc)
return rc;
}
return map_to_assuan_status (rc);
}
/* READKEY <hexified_certid>
Return the public key for the given cert or key ID as an standard
S-Expression. */
static int
cmd_readkey (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc;
unsigned char *cert = NULL;
size_t ncert, n;
KsbaCert kc = NULL;
KsbaSexp p;
if ((rc = open_card (ctrl)))
return rc;
rc = card_read_cert (ctrl->card_ctx, line, &cert, &ncert);
if (rc)
{
log_error ("card_read_cert failed: %s\n", gnupg_strerror (rc));
goto leave;
}
kc = ksba_cert_new ();
if (!kc)
{
xfree (cert);
rc = GNUPG_Out_Of_Core;
goto leave;
}
rc = ksba_cert_init_from_mem (kc, cert, ncert);
if (rc)
{
log_error ("failed to parse the certificate: %s\n", ksba_strerror (rc));
rc = map_ksba_err (rc);
goto leave;
}
p = ksba_cert_get_public_key (kc);
if (!p)
{
rc = GNUPG_No_Public_Key;
goto leave;
}
n = gcry_sexp_canon_len (p, 0, NULL, NULL);
rc = assuan_send_data (ctx, p, n);
rc = map_assuan_err (rc);
xfree (p);
leave:
ksba_cert_release (kc);
xfree (cert);
return map_to_assuan_status (rc);
}
/* SETDATA <hexstring>
The client should use this command to tell us the data he want to
sign. */
static int
cmd_setdata (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int n;
char *p;
unsigned char *buf;
/* parse the hexstring */
for (p=line,n=0; hexdigitp (p); p++, n++)
;
if (*p)
return set_error (Parameter_Error, "invalid hexstring");
if ((n&1))
return set_error (Parameter_Error, "odd number of digits");
n /= 2;
buf = xtrymalloc (n);
if (!buf)
return ASSUAN_Out_Of_Core;
ctrl->in_data.value = buf;
ctrl->in_data.valuelen = n;
for (p=line, n=0; n < ctrl->in_data.valuelen; p += 2, n++)
buf[n] = xtoi_2 (p);
return 0;
}
static int
pin_cb (void *opaque, const char *info, char **retstr)
{
ASSUAN_CONTEXT ctx = opaque;
char *command;
int rc;
char *value;
size_t valuelen;
*retstr = NULL;
log_debug ("asking for PIN '%s'\n", info);
rc = asprintf (&command, "NEEDPIN %s", info);
if (rc < 0)
return GNUPG_Out_Of_Core;
/* FIXME: Write an inquire function which returns the result in
secure memory */
rc = assuan_inquire (ctx, command, &value, &valuelen, MAXLEN_PIN);
free (command);
if (rc)
return map_assuan_err (rc);
if (!valuelen || value[valuelen-1])
{
/* We require that the returned value is an UTF-8 string */
xfree (value);
return GNUPG_Invalid_Response;
}
*retstr = value;
return 0;
}
/* PKSIGN <hexified_id>
*/
static int
cmd_pksign (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc;
void *outdata;
size_t outdatalen;
char *keyidstr;
if ((rc = open_card (ctrl)))
return rc;
/* We have to use a copy of the key ID because the function may use
the pin_cb which in turn uses the assuan line buffer and thus
overwriting the original line with the keyid */
keyidstr = strdup (line);
if (!keyidstr)
return ASSUAN_Out_Of_Core;
rc = card_sign (ctrl->card_ctx,
keyidstr, GCRY_MD_SHA1,
pin_cb, ctx,
ctrl->in_data.value, ctrl->in_data.valuelen,
&outdata, &outdatalen);
free (keyidstr);
if (rc)
{
log_error ("card_sign failed: %s\n", gnupg_strerror (rc));
}
else
{
rc = assuan_send_data (ctx, outdata, outdatalen);
xfree (outdata);
if (rc)
return rc; /* that is already an assuan error code */
}
return map_to_assuan_status (rc);
}
/* PKDECRYPT <hexified_id>
*/
static int
cmd_pkdecrypt (ASSUAN_CONTEXT ctx, char *line)
{
CTRL ctrl = assuan_get_pointer (ctx);
int rc;
void *outdata;
size_t outdatalen;
char *keyidstr;
if ((rc = open_card (ctrl)))
return rc;
keyidstr = strdup (line);
if (!keyidstr)
return ASSUAN_Out_Of_Core;
rc = card_decipher (ctrl->card_ctx,
keyidstr,
pin_cb, ctx,
ctrl->in_data.value, ctrl->in_data.valuelen,
&outdata, &outdatalen);
free (keyidstr);
if (rc)
{
log_error ("card_create_signature failed: %s\n", gnupg_strerror (rc));
}
else
{
rc = assuan_send_data (ctx, outdata, outdatalen);
xfree (outdata);
if (rc)
return rc; /* that is already an assuan error code */
}
return map_to_assuan_status (rc);
}
/* Tell the assuan library about our commands */
static int
register_commands (ASSUAN_CONTEXT ctx)
{
static struct {
const char *name;
int cmd_id;
int (*handler)(ASSUAN_CONTEXT, char *line);
} table[] = {
{ "SERIALNO", 0, cmd_serialno },
{ "LEARN", 0, cmd_learn },
{ "READCERT", 0, cmd_readcert },
{ "READKEY", 0, cmd_readkey },
{ "SETDATA", 0, cmd_setdata },
{ "PKSIGN", 0, cmd_pksign },
{ "PKDECRYPT", 0,cmd_pkdecrypt },
{ "", ASSUAN_CMD_INPUT, NULL },
{ "", ASSUAN_CMD_OUTPUT, NULL },
{ NULL }
};
int i, j, rc;
for (i=j=0; table[i].name; i++)
{
rc = assuan_register_command (ctx,
table[i].cmd_id? table[i].cmd_id
: (ASSUAN_CMD_USER + j++),
table[i].name, table[i].handler);
if (rc)
return rc;
}
assuan_set_hello_line (ctx, "GNU Privacy Guard's Smartcard server ready");
assuan_register_reset_notify (ctx, reset_notify);
assuan_register_option_handler (ctx, option_handler);
return 0;
}
/* Startup the server. If LISTEN_FD is given as -1, this is simple
piper server, otherwise it is a regular server */
void
scd_command_handler (int listen_fd)
{
int rc;
ASSUAN_CONTEXT ctx;
struct server_control_s ctrl;
memset (&ctrl, 0, sizeof ctrl);
scd_init_default_ctrl (&ctrl);
if (listen_fd == -1)
{
int filedes[2];
filedes[0] = 0;
filedes[1] = 1;
rc = assuan_init_pipe_server (&ctx, filedes);
}
else
{
rc = assuan_init_socket_server (&ctx, listen_fd);
}
if (rc)
{
log_error ("failed to initialize the server: %s\n",
assuan_strerror(rc));
scd_exit (2);
}
rc = register_commands (ctx);
if (rc)
{
log_error ("failed to register commands with Assuan: %s\n",
assuan_strerror(rc));
scd_exit (2);
}
assuan_set_pointer (ctx, &ctrl);
ctrl.server_local = xcalloc (1, sizeof *ctrl.server_local);
ctrl.server_local->assuan_ctx = ctx;
if (DBG_ASSUAN)
assuan_set_log_stream (ctx, log_get_stream ());
for (;;)
{
rc = assuan_accept (ctx);
if (rc == -1)
{
break;
}
else if (rc)
{
log_info ("Assuan accept problem: %s\n", assuan_strerror (rc));
break;
}
rc = assuan_process (ctx);
if (rc)
{
log_info ("Assuan processing failed: %s\n", assuan_strerror (rc));
continue;
}
}
reset_notify (ctx); /* used for cleanup */
assuan_deinit_server (ctx);
}