gnupg/g10/cardglue.c

/* cardglue.c - mainly dispatcher for card related functions.
 * Copyright (C) 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>
#ifndef ENABLE_CARD_SUPPORT
#error  not configured for card support.
#endif
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <stdarg.h>
#include <assert.h>

#include "options.h"
#include "packet.h"
#include "errors.h"
#include "memory.h"
#include "util.h"
#include "main.h"
#include "status.h"
#include "ttyio.h"
#include "i18n.h"

#include "cardglue.h"
#include "apdu.h"
#include "app-common.h"

struct ctrl_ctx_s {
  int (*status_cb)(void *opaque, const char *line);
  void *status_cb_arg;
};


static char *default_reader_port;
static APP current_app;




/* Create a serialno/fpr string from the serial number and the secret
   key.  caller must free the returned string.  There is no error
   return. [Taken from 1.9's keyid.c]*/
char *
serialno_and_fpr_from_sk (const unsigned char *sn, size_t snlen,
                          PKT_secret_key *sk)
{
  unsigned char fpr[MAX_FINGERPRINT_LEN];
  size_t fprlen;
  char *buffer, *p;
  int i;
  
  fingerprint_from_sk (sk, fpr, &fprlen);
  buffer = p = xmalloc (snlen*2 + 1 + fprlen*2 + 1);
  for (i=0; i < snlen; i++, p+=2)
    sprintf (p, "%02X", sn[i]);
  *p++ = '/';
  for (i=0; i < fprlen; i++, p+=2)
    sprintf (p, "%02X", fpr[i]);
  *p = 0;
  return buffer;
}


/* Send a line with status information via assuan and escape all given
   buffers. The variable elements are pairs of (char *, size_t),
   terminated with a (NULL, 0). */
void
send_status_info (CTRL ctrl, const char *keyword, ...)
{
  va_list arg_ptr;
  const unsigned char *value;
  size_t valuelen;
  char buf[950], *p;
  size_t n;
  
  va_start (arg_ptr, keyword);

  p = buf; 
  n = 0;
  valuelen = strlen (keyword);
  for ( ; valuelen && n < DIM (buf)-2; n++, valuelen--, keyword++)
    *p++ = *keyword;

  while ( (value = va_arg (arg_ptr, const unsigned char *)) )
    {
      valuelen = va_arg (arg_ptr, size_t);
      if (!valuelen)
        continue; /* empty buffer */
      if (n)
        {
          *p++ = ' ';
          n++;
        }
      for ( ; valuelen && n < DIM (buf)-2; n++, valuelen--, value++)
        {
          if (*value < ' ' || *value == '+')
            {
              sprintf (p, "%%%02X", *value);
              p += 3;
            }
          else if (*value == ' ')
            *p++ = '+';
          else
            *p++ = *value;
        }
    }
  *p = 0;
  ctrl->status_cb (ctrl->status_cb_arg, buf);

  va_end (arg_ptr);
}


void gcry_md_hash_buffer (int algo, void *digest,
			  const void *buffer, size_t length)
{
  MD_HANDLE h = md_open (algo, 0);
  if (!h)
    BUG();
  md_write (h, (byte *) buffer, length);
  md_final (h);
  memcpy (digest, md_read (h, algo), md_digest_length (algo));
  md_close (h);
}


/* This is a limited version of the one in 1.9 but it should be
   sufficient here. */
void
log_printf (const char *fmt, ...)
{
  va_list arg_ptr;

  va_start (arg_ptr, fmt);
  vfprintf (log_stream (), fmt, arg_ptr);
  va_end (arg_ptr);
}



/* Print a hexdump of BUFFER.  With TEXT of NULL print just the raw
   dump, with TEXT just an empty string, print a trailing linefeed,
   otherwise print an entire debug line. */
void
log_printhex (const char *text, const void *buffer, size_t length)
{
  if (text && *text)
    log_debug ("%s ", text);
  if (length)
    {
      const unsigned char *p = buffer;
      log_printf ("%02X", *p);
      for (length--, p++; length--; p++)
        log_printf (" %02X", *p);
    }
  if (text)
    log_printf ("\n");
}



void
app_set_default_reader_port (const char *portstr)
{
  xfree (default_reader_port);
  default_reader_port = portstr? xstrdup (portstr): NULL;
}


void
card_set_reader_port (const char *portstr)
{
  app_set_default_reader_port (portstr);
}


/* Retrieve the serial number and the time of the last update of the
   card.  The serial number is returned as a malloced string (hex
   encoded) in SERIAL and the time of update is returned in STAMP.  If
   no update time is available the returned value is 0.  Caller must
   free SERIAL unless the function returns an error. */
int 
app_get_serial_and_stamp (APP app, char **serial, time_t *stamp)
{
  unsigned char *buf, *p;
  int i;

  if (!app || !serial || !stamp)
    return gpg_error (GPG_ERR_INV_VALUE);

  *serial = NULL;
  *stamp = 0; /* not available */

  buf = xtrymalloc (app->serialnolen * 2 + 1);
  if (!buf)
    return gpg_error_from_errno (errno);
  for (p=buf, i=0; i < app->serialnolen; p +=2, i++)
    sprintf (p, "%02X", app->serialno[i]);
  *p = 0;
  *serial = buf;
  return 0;
}






/* Release the card info structure. */
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->fpr1valid = info->fpr2valid = info->fpr3valid = 0;
}


/* Open the current card and select the openpgp application.  Return
   an APP context handle to be used for further procesing or NULL on
   error or if no OpenPGP application exists.*/
static APP
open_card (void)
{
  int slot;
  int rc;
  APP app;

  card_close ();

 retry:
  slot = apdu_open_reader (default_reader_port);
  if (slot == -1)
    {
      log_error ("card reader not available\n");
      return NULL;
    }

  app = xcalloc (1, sizeof *app);
  app->slot = slot;
  rc = app_select_openpgp (app);
  if (rc && !opt.batch)
    {
      write_status_text (STATUS_CARDCTRL, "1");
      
      if ( cpr_get_answer_okay_cancel ("cardctrl.insert_card.okay",
           _("Please insert the card and hit return or enter 'c' to cancel: "),
                                       1) )
        {
          apdu_close_reader (slot);
          xfree (app);
          goto retry;
        }
    }
  if (rc)
    {
      log_info ("selecting openpgp failed: %s\n", gpg_strerror (rc));
      apdu_close_reader (slot);
      xfree (app);
      return NULL;
    }

  app->initialized = 1;
  current_app = app;
  if (is_status_enabled () )
    {
      int i;
      char *p, *buf;

      buf = xmalloc (5 + app->serialnolen * 2 + 1);
      p = stpcpy (buf, "3 ");
      for (i=0; i < app->serialnolen; p +=2, i++)
        sprintf (p, "%02X", app->serialno[i]);
      write_status_text (STATUS_CARDCTRL, buf);
      xfree (buf);
    }

  return app;
}

void
card_close (void)
{
  if (current_app)
    {
      APP app = current_app;
      current_app = NULL;

      apdu_close_reader (app->slot);
      xfree (app);
    }
}


/* Check that the serial number of the current card (as described by
   APP) matches SERIALNO.  If there is no match and we are not in
   batch mode, present a prompt to insert the desired card.  The
   function return 0 is the present card is okay, -1 if the user
   selected to insert a new card or an error value.  Note that the
   card context will be closed in all cases except for 0 as return
   value. */
static int
check_card_serialno (APP app, const char *serialno)
{
  const char *s;
  int ask = 0;
  int n;
  
  for (s = serialno, n=0; *s != '/' && hexdigitp (s); s++, n++)
    ;
  if (n != 32)
    {
      log_error ("invalid serial number in keyring detected\n");
      return gpg_error (GPG_ERR_INV_ID);
    }
  if (app->serialnolen != 16)
    ask = 1;
  for (s = serialno, n=0; !ask && n < 16; s += 2, n++)
    if (app->serialno[n] != xtoi_2 (s))
      ask = 1;
  if (ask)
    {
      char buf[5+32+1];

      card_close ();
      tty_printf (_("Please remove the current card and "
                    "insert the one with the serial number:\n"
                    "   %.*s\n"), 32, serialno);

      sprintf (buf, "1 %.32s", serialno);
      write_status_text (STATUS_CARDCTRL, buf);

      if ( cpr_get_answer_okay_cancel ("cardctrl.change_card.okay",
                          _("Hit return when ready "
                            "or enter 'c' to cancel: "),
                                       1) )
        return -1;
      return gpg_error (GPG_ERR_INV_ID);
    }
  return 0;
}



/* 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 = xmalloc (strlen (s)+1);
  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;
}

/* 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 = xmalloc (s + 1 - line);
  memcpy (p, line, s-line);
  p[s-line] = 0;
  return p;
}



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);
    }
  
  return 0;
}


/* Return card info. */
int 
agent_learn (struct agent_card_info_s *info)
{
  APP app;
  int rc;
  struct ctrl_ctx_s ctrl;
  time_t stamp;
  char *serial;
  
  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  memset (info, 0, sizeof *info);
  memset (&ctrl, 0, sizeof ctrl);
  ctrl.status_cb = learn_status_cb;
  ctrl.status_cb_arg = info;

  rc = app_get_serial_and_stamp (app, &serial, &stamp);
  if (!rc)
    {
      send_status_info (&ctrl, "SERIALNO", serial, strlen(serial), NULL, 0);
      xfree (serial);
      rc = app->fnc.learn_status (app, &ctrl);
    }

  return rc;
}

/* Get an attribite from the card. Make sure info is initialized. */
int 
agent_scd_getattr (const char *name, struct agent_card_info_s *info)
{
  APP app;
  struct ctrl_ctx_s ctrl;

  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  ctrl.status_cb = learn_status_cb;
  ctrl.status_cb_arg = info;
  return app->fnc.getattr (app, &ctrl, name);
}



static int 
pin_cb (void *opaque, const char *info, char **retstr)
{
  char *value;
  int canceled;
  int isadmin = (info && strstr (info, "dmin"));


  *retstr = NULL;
  log_debug ("asking for PIN '%s'\n", info);

  value = ask_passphrase (info, 
                          isadmin? "passphrase.adminpin.ask"
                                 : "passphrase.pin.ask", 
                          isadmin?  _("Enter Admin PIN: ") : _("Enter PIN: "),
                          &canceled);
  if (!value && canceled)
    return -1;
  else if (!value)
    return G10ERR_GENERAL;

  *retstr = value;
  return 0;
}



/* Send a SETATTR command to the SCdaemon. */
int 
agent_scd_setattr (const char *name,
                   const unsigned char *value, size_t valuelen)
{
  APP app;

  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  return app->fnc.setattr (app, name, pin_cb, NULL, value, valuelen);
}


static int
genkey_status_cb (void *opaque, const char *line)
{
  struct agent_card_genkey_s *parm = opaque;
  const char *keyword = line;
  int keywordlen;

  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))
    {
      MPI a;
      const char *name = line;
      char *buf;

      while (*line && !spacep (line))
        line++;
      while (spacep (line))
        line++;

      buf = xmalloc ( 2 + strlen (line) + 1);
      strcpy (stpcpy (buf, "0x"), line);
      a = mpi_alloc (300);
      if( mpi_fromstr (a, buf) )
        log_error ("error parsing received key data\n");
      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");
          mpi_free (a);
        }
      xfree (buf);
    }
  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. */
int 
agent_scd_genkey (struct agent_card_genkey_s *info, int keyno, int force)
{
  APP app;
  char keynostr[20];
  struct ctrl_ctx_s ctrl;

  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  memset (info, 0, sizeof *info);
  sprintf (keynostr, "%d", keyno);
  ctrl.status_cb = genkey_status_cb;
  ctrl.status_cb_arg = info;

  return app->fnc.genkey (app, &ctrl, keynostr,
                           force? 1:0,
                           pin_cb, NULL);
}

/* Send a PKSIGN command to the SCdaemon. */
int 
agent_scd_pksign (const char *serialno, int hashalgo,
                  const unsigned char *indata, size_t indatalen,
                  unsigned char **r_buf, size_t *r_buflen)
{
  APP app;
  int rc;

  *r_buf = NULL;
  *r_buflen = 0;
 retry:
  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  /* Check that the card's serialnumber is as required.*/
  rc = check_card_serialno (app, serialno);
  if (rc == -1)
    goto retry;
  if (rc)
    return rc;

  return app->fnc.sign (app, serialno, hashalgo,
                        pin_cb, NULL,
                        indata, indatalen,
                        r_buf, r_buflen);
}


/* Send a PKDECRYPT command to the SCdaemon. */
int 
agent_scd_pkdecrypt (const char *serialno,
                     const unsigned char *indata, size_t indatalen,
                     unsigned char **r_buf, size_t *r_buflen)
{
  APP app;
  int rc;

  *r_buf = NULL;
  *r_buflen = 0;
 retry:
  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  /* Check that the card's serialnumber is as required.*/
  rc = check_card_serialno (app, serialno);
  if (rc == -1)
    goto retry;
  if (rc)
    return rc;

  return app->fnc.decipher (app, serialno, 
                            pin_cb, NULL,
                            indata, indatalen,
                            r_buf, r_buflen);
}

/* Change the PIN of an OpenPGP card or reset the retry counter. */
int 
agent_scd_change_pin (int chvno)
{
  APP app;
  char chvnostr[20];
  int reset = 0;

  reset = (chvno >= 100);
  chvno %= 100;

  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  sprintf (chvnostr, "%d", chvno);
  return app->fnc.change_pin (app, NULL, chvnostr, reset,
                              pin_cb, NULL);
}

/* Perform a CHECKPIN operation.  SERIALNO should be the seriial
   number of the card - optioanlly followed by the fingerprint;
   however the fingerprint is ignored here. */
int
agent_scd_checkpin (const char *serialnobuf)
{
  APP app;

  app = current_app? current_app : open_card ();
  if (!app)
    return gpg_error (GPG_ERR_CARD);

  return app->fnc.check_pin (app, serialnobuf, pin_cb, NULL);
}