gnupg/scd/app-openpgp.c

/* app-openpgp.c - The OpenPGP card application.
 *	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>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include "scdaemon.h"
#include "app-common.h"
#include "iso7816.h"



static struct {
  int tag;
  int constructed;
  int get_from;  /* Constructed DO with this DO or 0 for direct access. */
  int binary;
  char *desc;
} data_objects[] = {
  { 0x005E, 0,    0, 1, "Login Data" },
  { 0x5F50, 0,    0, 0, "URL" },
  { 0x0065, 1,    0, 1, "Cardholder Related Data"},
  { 0x005B, 0, 0x65, 0, "Name" },
  { 0x5F2D, 0, 0x65, 0, "Language preferences" },
  { 0x5F35, 0, 0x65, 0, "Sex" },
  { 0x006E, 1,    0, 1, "Application Related Data" },
  { 0x004F, 0, 0x6E, 1, "AID" },
  { 0x0073, 1,    0, 1, "Discretionary Data Objects" },
  { 0x0047, 0, 0x6E, 1, "Card Capabilities" },
  { 0x00C0, 0, 0x6E, 1, "Extended Card Capabilities" },
  { 0x00C1, 0, 0x6E, 1, "Algorithm Attributes Signature" },
  { 0x00C2, 0, 0x6E, 1, "Algorithm Attributes Decryption" },
  { 0x00C3, 0, 0x6E, 1, "Algorithm Attributes Authentication" },
  { 0x00C4, 0, 0x6E, 1, "CHV Status Bytes" },
  { 0x00C5, 0, 0x6E, 1, "Fingerprints" },
  { 0x00C6, 0, 0x6E, 1, "CA Fingerprints" },
  { 0x007A, 1,    0, 1, "Security Support Template" },
  { 0x0093, 0, 0x7A, 1, "Digital Signature Counter" },
  { 0 }
};


static unsigned long get_sig_counter (APP app);


/* Locate a TLV encoded data object in BUFFER of LENGTH and
   return a pointer to value as well as its length in NBYTES.  Return
   NULL if it was not found.  Note, that the function does not check
   whether the value fits into the provided buffer. 

   FIXME: Move this to an extra file, it is mostly duplicated from card.c.
*/
static const unsigned char *
find_tlv (const unsigned char *buffer, size_t length,
          int tag, size_t *nbytes, int nestlevel)
{
  const unsigned char *s = buffer;
  size_t n = length;
  size_t len;
  int this_tag;
  int composite;
    
  for (;;)
    {
      buffer = s;
      if (n < 2)
        return NULL; /* buffer definitely too short for tag and length. */
      if (!*s || *s == 0xff)
        { /* Skip optional filler between TLV objects. */
          s++;
          n--;
          continue;
        }
      composite = !!(*s & 0x20);
      if ((*s & 0x1f) == 0x1f)
        { /* more tag bytes to follow */
          s++;
          n--;
          if (n < 2)
            return NULL; /* buffer definitely too short for tag and length. */
          if ((*s & 0x1f) == 0x1f)
            return NULL; /* We support only up to 2 bytes. */
          this_tag = (s[-1] << 8) | (s[0] & 0x7f);
        }
      else
        this_tag = s[0];
      len = s[1];
      s += 2; n -= 2;
      if (len < 0x80)
        ;
      else if (len == 0x81)
        { /* One byte length follows. */
          if (!n)
            return NULL; /* we expected 1 more bytes with the length. */
          len = s[0];
          s++; n--;
        }
      else if (len == 0x82)
        { /* Two byte length follows. */
          if (n < 2)
            return NULL; /* we expected 2 more bytes with the length. */
          len = (s[0] << 8) | s[1];
          s += 2; n -= 2;
        }
      else
        return NULL; /* APDU limit is 65535, thus it does not make
                        sense to assume longer length fields. */

      if (composite && nestlevel < 100)
        { /* Dive into this composite DO after checking for too deep
             nesting. */
          const unsigned char *tmp_s;
          size_t tmp_len;
          
          tmp_s = find_tlv (s, len, tag, &tmp_len, nestlevel+1);
          if (tmp_s)
            {
              *nbytes = tmp_len;
              return tmp_s;
            }
        }

      if (this_tag == tag)
        {
          *nbytes = len;
          return s;
        }
      if (len > n)
        return NULL; /* buffer too short to skip to the next tag. */
      s += len; n -= len;
    }
}


/* Get the DO identified by TAG from the card in SLOT and return a
   buffer with its content in RESULT and NBYTES.  The return value is
   NULL if not found or a pointer which must be used to release the
   buffer holding value. */
static void *
get_one_do (int slot, int tag, unsigned char **result, size_t *nbytes)
{
  int rc, i;
  unsigned char *buffer;
  size_t buflen;
  unsigned char *value;
  size_t valuelen;

  *result = NULL;
  *nbytes = 0;
  for (i=0; data_objects[i].tag && data_objects[i].tag != tag; i++)
    ;

  value = NULL;
  rc = -1;
  if (data_objects[i].tag && data_objects[i].get_from)
    {
      rc = iso7816_get_data (slot, data_objects[i].get_from,
                             &buffer, &buflen);
      if (!rc)
        {
          const unsigned char *s;

          s = find_tlv (buffer, buflen, tag, &valuelen, 0);
          if (!s)
            value = NULL; /* not found */
          else if (valuelen > buflen - (s - buffer))
            {
              log_error ("warning: constructed DO too short\n");
              value = NULL;
              xfree (buffer); buffer = NULL;
            }
          else
            value = buffer + (s - buffer);
        }
    }

  if (!value) /* Not in a constructed DO, try simple. */
    {
      rc = iso7816_get_data (slot, tag, &buffer, &buflen);
      if (!rc)
        {
          value = buffer;
          valuelen = buflen;
        }
    }

  if (!rc)
    {
      *nbytes = valuelen;
      *result = value;
      return buffer;
    }
  return NULL;
}

#if 0 /* not used */
static void
dump_one_do (int slot, int tag)
{
  int rc, i;
  unsigned char *buffer;
  size_t buflen;
  const char *desc;
  int binary;
  const unsigned char *value;
  size_t valuelen;

  for (i=0; data_objects[i].tag && data_objects[i].tag != tag; i++)
    ;
  desc = data_objects[i].tag? data_objects[i].desc : "?";
  binary = data_objects[i].tag? data_objects[i].binary : 1;

  value = NULL;
  rc = -1;
  if (data_objects[i].tag && data_objects[i].get_from)
    {
      rc = iso7816_get_data (slot, data_objects[i].get_from,
                             &buffer, &buflen);
      if (!rc)
        {
          value = find_tlv (buffer, buflen, tag, &valuelen, 0);
          if (!value)
            ; /* not found */
          else if (valuelen > buflen - (value - buffer))
            {
              log_error ("warning: constructed DO too short\n");
              value = NULL;
              xfree (buffer); buffer = NULL;
            }
        }
    }

  if (!value) /* Not in a constructed DO, try simple. */
    {
      rc = iso7816_get_data (slot, tag, &buffer, &buflen);
      if (!rc)
        {
          value = buffer;
          valuelen = buflen;
        }
    }
  if (rc == 0x6a88)
    log_info ("DO `%s' not available\n", desc);
  else if (rc) 
    log_info ("DO `%s' not available (rc=%04X)\n", desc, rc);
  else
    {
      if (binary)
        {
          log_info ("DO `%s': ", desc);
          log_printhex ("", value, valuelen);
        }
      else
        log_info ("DO `%s': `%.*s'\n",
                  desc, (int)valuelen, value); /* FIXME: sanitize */
      xfree (buffer);
    }
}
#endif /*not used*/


static void
dump_all_do (int slot)
{
  int rc, i, j;
  unsigned char *buffer;
  size_t buflen;
  
  for (i=0; data_objects[i].tag; i++)
    {
      if (data_objects[i].get_from)
        continue;

      rc = iso7816_get_data (slot, data_objects[i].tag, &buffer, &buflen);
      if (rc == 0x6a88)
        ;
      else if (rc) 
        log_info ("DO `%s' not available (rc=%04X)\n",
                  data_objects[i].desc, rc);
      else
        {
          if (data_objects[i].binary)
            {
              log_info ("DO `%s': ", data_objects[i].desc);
              log_printhex ("", buffer, buflen);
            }
          else
            log_info ("DO `%s': `%.*s'\n",
                      data_objects[i].desc,
                      (int)buflen, buffer); /* FIXME: sanitize */
        }

      if (data_objects[i].constructed)
        {
          for (j=0; data_objects[j].tag; j++)
            {
              const unsigned char *value;
              size_t valuelen;

              if (j==i || data_objects[i].tag != data_objects[j].get_from)
                continue;
              value = find_tlv (buffer, buflen,
                                data_objects[j].tag, &valuelen, 0);
              if (!value)
                ; /* not found */
              else if (valuelen > buflen - (value - buffer))
                log_error ("warning: constructed DO too short\n");
              else
                {
                  if (data_objects[j].binary)
                    {
                      log_info ("DO `%s': ", data_objects[j].desc);
                      log_printhex ("", value, valuelen);
                    }
                  else
                    log_info ("DO `%s': `%.*s'\n",
                              data_objects[j].desc,
                              (int)valuelen, value); /* FIXME: sanitize */
                }
            }
        }
      xfree (buffer); buffer = NULL;
    }
}


/* Count the number of bits, assuming the A represents an unsigned big
   integer of length LEN bytes. */
static unsigned int
count_bits (const unsigned char *a, size_t len)
{
  unsigned int n = len * 8;
  int i;

  for (; len && !*a; len--, a++, n -=8)
    ;
  if (len)
    {
      for (i=7; i && !(*a & (1<<i)); i--)
        n--;
    }
  return n;
}

/* Note, that FPR must be at least 20 bytes. */
static int 
store_fpr (int slot, int keynumber, u32 timestamp,
           const unsigned char *m, size_t mlen,
           const unsigned char *e, size_t elen, 
           unsigned char *fpr, unsigned int card_version)
{
  unsigned int n, nbits;
  unsigned char *buffer, *p;
  int rc;
  
  for (; mlen && !*m; mlen--, m++) /* strip leading zeroes */
    ;
  for (; elen && !*e; elen--, e++) /* strip leading zeroes */
    ;

  n = 6 + 2 + mlen + 2 + elen;
  p = buffer = xtrymalloc (3 + n);
  if (!buffer)
    return out_of_core ();
  
  *p++ = 0x99;     /* ctb */
  *p++ = n >> 8;   /* 2 byte length header */
  *p++ = n;
  *p++ = 4;        /* key packet version */
  *p++ = timestamp >> 24;
  *p++ = timestamp >> 16;
  *p++ = timestamp >>  8;
  *p++ = timestamp;
  *p++ = 1; /* RSA */
  nbits = count_bits (m, mlen);
  *p++ = nbits >> 8;
  *p++ = nbits;
  memcpy (p, m, mlen); p += mlen;
  nbits = count_bits (e, elen);
  *p++ = nbits >> 8;
  *p++ = nbits;
  memcpy (p, e, elen); p += elen;
    
  log_printhex ("fprbuf:", buffer, n+3);
  gcry_md_hash_buffer (GCRY_MD_SHA1, fpr, buffer, n+3);

  xfree (buffer);

  rc = iso7816_put_data (slot, (card_version > 0x0007? 0xC7 : 0xC6)
                               + keynumber, fpr, 20);
  if (rc)
    log_error ("failed to store the fingerprint: rc=%04X\n", rc);

  return rc;
}

       
static void
send_fpr_if_not_null (CTRL ctrl, const char *keyword,
                      int number, const unsigned char *fpr)
{                      
  int i;
  char buf[41];
  char numbuf[25];

  for (i=0; i < 20 && !fpr[i]; i++)
    ;
  if (i==20)
    return; /* All zero. */
  for (i=0; i< 20; i++)
    sprintf (buf+2*i, "%02X", fpr[i]);
  if (number == -1)
    *numbuf = 0; /* Don't print the key number */
  else
    sprintf (numbuf, "%d", number);
  send_status_info (ctrl, keyword,
                    numbuf, (size_t)strlen(numbuf),
                    buf, (size_t)strlen (buf), NULL, 0);
}

static void
send_key_data (CTRL ctrl, const char *name, 
               const unsigned char *a, size_t alen)
{
  char *p, *buf = xmalloc (alen*2+1);
  
  for (p=buf; alen; a++, alen--, p += 2)
    sprintf (p, "%02X", *a);

  send_status_info (ctrl, "KEY-DATA",
                    name, (size_t)strlen(name), 
                    buf, (size_t)strlen (buf),
                    NULL, 0);
  xfree (buf);
}



static int
do_learn_status (APP app, CTRL ctrl)
{
  void *relptr;
  unsigned char *value;
  size_t valuelen;
  int i;

  relptr = get_one_do (app->slot, 0x005B, &value, &valuelen);
  if (relptr)
    {
      send_status_info (ctrl, "DISP-NAME", value, valuelen, NULL, 0);
      xfree (relptr);
    }
  relptr = get_one_do (app->slot, 0x5F2D, &value, &valuelen);
  if (relptr)
    {
      send_status_info (ctrl, "DISP-LANG", value, valuelen, NULL, 0);
      xfree (relptr);
    }
  relptr = get_one_do (app->slot, 0x5F35, &value, &valuelen);
  if (relptr)
    {
      send_status_info (ctrl, "DISP-SEX", value, valuelen, NULL, 0);
      xfree (relptr);
    }
  relptr = get_one_do (app->slot, 0x5F50, &value, &valuelen);
  if (relptr)
    {
      send_status_info (ctrl, "PUBKEY-URL", value, valuelen, NULL, 0);
      xfree (relptr);
    }
  relptr = get_one_do (app->slot, 0x005E, &value, &valuelen);
  if (relptr)
    {
      send_status_info (ctrl, "LOGIN-DATA", value, valuelen, NULL, 0);
      xfree (relptr);
    }

  relptr = get_one_do (app->slot, 0x00C5, &value, &valuelen);
  if (relptr && valuelen >= 60)
    {
      for (i=0; i < 3; i++)
        send_fpr_if_not_null (ctrl, "KEY-FPR", i+1, value+i*20);
    }
  xfree (relptr);
  relptr = get_one_do (app->slot, 0x00C6, &value, &valuelen);
  if (relptr && valuelen >= 60)
    {
      for (i=0; i < 3; i++)
        send_fpr_if_not_null (ctrl, "CA-FPR", i+1, value+i*20);
    }
  xfree (relptr);
  relptr = get_one_do (app->slot, 0x00C4, &value, &valuelen);
  if (relptr)
    {
      char numbuf[7*23];

      for (i=0,*numbuf=0; i < valuelen && i < 7; i++)
        sprintf (numbuf+strlen (numbuf), " %d", value[i]); 
      send_status_info (ctrl, "CHV-STATUS", numbuf, strlen (numbuf), NULL, 0);
      xfree (relptr);
    }

  {
    unsigned long ul = get_sig_counter (app);
    char numbuf[23];

    sprintf (numbuf, "%lu", ul);
    send_status_info (ctrl, "SIG-COUNTER", numbuf, strlen (numbuf), NULL, 0);
  }
  return 0;
}


/* Handle the SETATTR operation. All arguments are already basically
   checked. */
static int 
do_setattr (APP app, const char *name,
            int (*pincb)(void*, const char *, char **),
            void *pincb_arg,
            const unsigned char *value, size_t valuelen)
{
  gpg_error_t rc;
  int idx;
  static struct {
    const char *name;
    int tag;
  } table[] = {
    { "DISP-NAME",    0x005B },
    { "LOGIN-DATA",   0x005E },
    { "DISP-LANG",    0x5F2D },
    { "DISP-SEX",     0x5F35 },
    { "PUBKEY-URL",   0x5F50 },
    { "CHV-STATUS-1", 0x00C4 },
    { "CA-FPR-1",     0x00CA },
    { "CA-FPR-2",     0x00CB },
    { "CA-FPR-3",     0x00CC },
    { NULL, 0 }
  };


  for (idx=0; table[idx].name && strcmp (table[idx].name, name); idx++)
    ;
  if (!table[idx].name)
    return gpg_error (GPG_ERR_INV_NAME); 

  if (!app->did_chv3)
    {
      char *pinvalue;

      rc = pincb (pincb_arg, "Admin PIN (CHV3)",
                  &pinvalue);
/*        pinvalue = xstrdup ("12345678"); */
/*        rc = 0; */
      if (rc)
        {
          log_info ("PIN callback returned error: %s\n", gpg_strerror (rc));
          return rc;
        }

      rc = iso7816_verify (app->slot, 0x83, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV3 failed\n");
          rc = gpg_error (GPG_ERR_GENERAL);
          return rc;
        }
      app->did_chv3 = 1;
    }

  rc = iso7816_put_data (app->slot, table[idx].tag, value, valuelen);
  if (rc)
    log_error ("failed to set `%s': %s\n", table[idx].name, gpg_strerror (rc));
  /* FIXME: If this fails we should *once* try again after
     doing a verify command, so that in case of a problem with
     tracking the verify operation we have a fallback. */

  return rc;
}

/* Handle the PASSWD command. */
static int 
do_change_pin (APP app, CTRL ctrl,  const char *chvnostr, int reset_mode,
               int (*pincb)(void*, const char *, char **),
               void *pincb_arg)
{
  int rc = 0;
  int chvno = atoi (chvnostr);
  char *pinvalue;

  if (reset_mode && chvno == 3)
    {
      rc = gpg_error (GPG_ERR_INV_ID);
      goto leave;
    }
  else if (reset_mode || chvno == 3)
    {
      rc = pincb (pincb_arg, "Admin PIN", &pinvalue); 
      if (rc)
        {
          log_error ("error getting PIN: %s\n", gpg_strerror (rc));
          goto leave;
        }
      rc = iso7816_verify (app->slot, 0x83, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV3 failed: rc=%04X\n", rc);
          goto leave;
        }
    }
  else if (chvno == 1)
    {
      rc = pincb (pincb_arg, "Signature PIN", &pinvalue); 
      if (rc)
        {
          log_error ("error getting PIN: %s\n", gpg_strerror (rc));
          goto leave;
        }
      rc = iso7816_verify (app->slot, 0x81, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV1 failed: rc=%04X\n", rc);
          goto leave;
        }
    }
  else if (chvno == 2)
    {
      rc = pincb (pincb_arg, "Decryption PIN", &pinvalue); 
      if (rc)
        {
          log_error ("error getting PIN: %s\n", gpg_strerror (rc));
          goto leave;
        }
      rc = iso7816_verify (app->slot, 0x82, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV2 failed: rc=%04X\n", rc);
          goto leave;
        }
    }
  else
    {
      rc = gpg_error (GPG_ERR_INV_ID);
      goto leave;
    }

  
  rc = pincb (pincb_arg, chvno == 1? "New Signature PIN" :
                         chvno == 2? "New Decryption PIN" :
                         chvno == 3? "New Admin PIN" : "?", &pinvalue); 
  if (rc)
    {
      log_error ("error getting new PIN: %s\n", gpg_strerror (rc));
      goto leave;
    }

  if (reset_mode)
    rc = iso7816_reset_retry_counter (app->slot, 0x80 + chvno,
                                      pinvalue, strlen (pinvalue));
  else
    rc = iso7816_change_reference_data (app->slot, 0x80 + chvno,
                                        NULL, 0,
                                        pinvalue, strlen (pinvalue));
  xfree (pinvalue);


 leave:
  return rc;
}



/* Handle the GENKEY command. */
static int 
do_genkey (APP app, CTRL ctrl,  const char *keynostr, unsigned int flags,
          int (*pincb)(void*, const char *, char **),
          void *pincb_arg)
{
  int rc;
  int i;
  char numbuf[30];
  unsigned char fprbuf[20];
  const unsigned char *fpr;
  const unsigned char *keydata, *m, *e;
  unsigned char *buffer;
  size_t buflen, keydatalen, n, mlen, elen;
  time_t created_at;
  int keyno = atoi (keynostr);
  int force = (flags & 1);
  time_t start_at;

  if (keyno < 1 || keyno > 3)
    return gpg_error (GPG_ERR_INV_ID);
  keyno--;

  rc = iso7816_get_data (app->slot, 0x006E, &buffer, &buflen);
  if (rc)
    {
      log_error ("error reading application data\n");
      return gpg_error (GPG_ERR_GENERAL);
    }
  fpr = find_tlv (buffer, buflen, 0x00C5, &n, 0);
  if (!fpr || n != 60)
    {
      rc = gpg_error (GPG_ERR_GENERAL);
      log_error ("error reading fingerprint DO\n");
      goto leave;
    }
  fpr += 20*keyno;
  for (i=0; i < 20 && !fpr[i]; i++)
    ;
  if (i!=20 && !force)
    {
      rc = gpg_error (GPG_ERR_EEXIST);
      log_error ("key already exists\n");
      goto leave;
    }
  else if (i!=20)
    log_info ("existing key will be replaced\n");
  else
    log_info ("generating new key\n");

  {
    char *pinvalue;
    rc = pincb (pincb_arg, "Admin PIN", &pinvalue); 
    if (rc)
      {
        log_error ("error getting PIN: %s\n", gpg_strerror (rc));
        return rc;
      }
    rc = iso7816_verify (app->slot, 0x83, pinvalue, strlen (pinvalue));
    xfree (pinvalue);
  }
  if (rc)
    {
      log_error ("verify CHV3 failed: rc=%04X\n", rc);
      goto leave;
    }

  xfree (buffer); buffer = NULL;
#if 1
  log_info ("please wait while key is being generated ...\n");
  start_at = time (NULL);
  rc = iso7816_generate_keypair 
#else
#warning key generation temporary replaced by reading an existing key.
  rc = iso7816_read_public_key
#endif
                              (app->slot, 
                                 keyno == 0? "\xB6" :
                                 keyno == 1? "\xB8" : "\xA4",
                                 2,
                                 &buffer, &buflen);
  if (rc)
    {
      rc = gpg_error (GPG_ERR_CARD);
      log_error ("generating key failed\n");
      goto leave;
    }
  log_info ("key generation completed (%d seconds)\n",
            (int)(time (NULL) - start_at));
  keydata = find_tlv (buffer, buflen, 0x7F49, &keydatalen, 0);
  if (!keydata)
    {
      rc = gpg_error (GPG_ERR_CARD);
      log_error ("response does not contain the public key data\n");
      goto leave;
    }
 
  m = find_tlv (keydata, keydatalen, 0x0081, &mlen, 0);
  if (!m)
    {
      rc = gpg_error (GPG_ERR_CARD);
      log_error ("response does not contain the RSA modulus\n");
      goto leave;
    }
/*    log_printhex ("RSA n:", m, mlen); */
  send_key_data (ctrl, "n", m, mlen);

  e = find_tlv (keydata, keydatalen, 0x0082, &elen, 0);
  if (!e)
    {
      rc = gpg_error (GPG_ERR_CARD);
      log_error ("response does not contain the RSA public exponent\n");
      goto leave;
    }
/*    log_printhex ("RSA e:", e, elen); */
  send_key_data (ctrl, "e", e, elen);

  created_at = gnupg_get_time ();
  sprintf (numbuf, "%lu", (unsigned long)created_at);
  send_status_info (ctrl, "KEY-CREATED-AT",
                    numbuf, (size_t)strlen(numbuf), NULL, 0);

  rc = store_fpr (app->slot, keyno, (u32)created_at,
                  m, mlen, e, elen, fprbuf, app->card_version);
  if (rc)
    goto leave;
  send_fpr_if_not_null (ctrl, "KEY-FPR", -1, fprbuf);


 leave:
  xfree (buffer);
  return rc;
}


static unsigned long
get_sig_counter (APP app)
{
  void *relptr;
  unsigned char *value;
  size_t valuelen;
  unsigned long ul;

  relptr = get_one_do (app->slot, 0x0093, &value, &valuelen);
  if (!relptr)
    return 0;
  if (valuelen == 3 )
    ul = (value[0] << 16) | (value[1] << 8) | value[2];
  else
    {
      log_error ("invalid structure of OpenPGP card (DO 0x93)\n");
      ul = 0;
    }
  xfree (relptr);
  return ul;
}

static int
compare_fingerprint (APP app, int keyno, unsigned char *sha1fpr)
{
  const unsigned char *fpr;
  unsigned char *buffer;
  size_t buflen, n;
  int rc, i;
  
  assert (keyno >= 1 && keyno <= 3);

  rc = iso7816_get_data (app->slot, 0x006E, &buffer, &buflen);
  if (rc)
    {
      log_error ("error reading application data\n");
      return gpg_error (GPG_ERR_GENERAL);
    }
  fpr = find_tlv (buffer, buflen, 0x00C5, &n, 0);
  if (!fpr || n != 60)
    {
      xfree (buffer);
      log_error ("error reading fingerprint DO\n");
      return gpg_error (GPG_ERR_GENERAL);
    }
  fpr += (keyno-1)*20;
  for (i=0; i < 20; i++)
    if (sha1fpr[i] != fpr[i])
      {
        xfree (buffer);
        return gpg_error (GPG_ERR_WRONG_SECKEY);
      }
  xfree (buffer);
  return 0;
}



/* Compute a digital signature on INDATA which is expected to be the
   raw message digest. For this application the KEYIDSTR consists of
   the serialnumber and the fingerprint delimited by a slash.

   Note that this fucntion may return the error code
   GPG_ERR_WRONG_CARD to indicate that the card currently present does
   not match the one required for the requested action (e.g. the
   serial number does not match). */
static int 
do_sign (APP app, const char *keyidstr, int hashalgo,
         int (*pincb)(void*, const char *, char **),
         void *pincb_arg,
         const void *indata, size_t indatalen,
         unsigned char **outdata, size_t *outdatalen )
{
  static unsigned char sha1_prefix[15] = /* Object ID is 1.3.14.3.2.26 */
  { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03,
    0x02, 0x1a, 0x05, 0x00, 0x04, 0x14 };
  static unsigned char rmd160_prefix[15] = /* Object ID is 1.3.36.3.2.1 */
  { 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x24, 0x03,
    0x02, 0x01, 0x05, 0x00, 0x04, 0x14 };
  int rc;
  unsigned char data[35];
  unsigned char tmp_sn[20]; /* actually 16 but we use it also for the fpr. */
  const char *s;
  int n;
  const char *fpr = NULL;
  unsigned long sigcount;

  if (!keyidstr || !*keyidstr)
    return gpg_error (GPG_ERR_INV_VALUE);
  if (indatalen != 20)
    return gpg_error (GPG_ERR_INV_VALUE);

  /* Check whether an OpenPGP card of any version has been requested. */
  if (strlen (keyidstr) < 32 || strncmp (keyidstr, "D27600012401", 12))
    return gpg_error (GPG_ERR_INV_ID);
  
  for (s=keyidstr, n=0; hexdigitp (s); s++, n++)
    ;
  if (n != 32)
    return gpg_error (GPG_ERR_INV_ID);
  else if (!*s)
    ; /* no fingerprint given: we allow this for now. */
  else if (*s == '/')
    fpr = s + 1; 
  else
    return gpg_error (GPG_ERR_INV_ID);

  for (s=keyidstr, n=0; n < 16; s += 2, n++)
    tmp_sn[n] = xtoi_2 (s);

  if (app->serialnolen != 16)
    return gpg_error (GPG_ERR_INV_CARD);
  if (memcmp (app->serialno, tmp_sn, 16))
    return gpg_error (GPG_ERR_WRONG_CARD);

  /* If a fingerprint has been specified check it against the one on
     the card.  This is allows for a meaningful error message in case
     the key on the card has been replaced but the shadow information
     known to gpg was not updated.  If there is no fingerprint, gpg
     will detect a bogus signature anyway due to the
     verify-after-signing feature. */
  if (fpr)
    {
      for (s=fpr, n=0; hexdigitp (s); s++, n++)
        ;
      if (n != 40)
        return gpg_error (GPG_ERR_INV_ID);
      else if (!*s)
        ; /* okay */
      else
        return gpg_error (GPG_ERR_INV_ID);

      for (s=fpr, n=0; n < 20; s += 2, n++)
        tmp_sn[n] = xtoi_2 (s);
      rc = compare_fingerprint (app, 1, tmp_sn);
      if (rc)
        return rc;
    }

  if (hashalgo == GCRY_MD_SHA1)
    memcpy (data, sha1_prefix, 15);
  else if (hashalgo == GCRY_MD_RMD160)
    memcpy (data, rmd160_prefix, 15);
  else 
    return gpg_error (GPG_ERR_UNSUPPORTED_ALGORITHM);
  memcpy (data+15, indata, indatalen);

  sigcount = get_sig_counter (app);
  log_info ("signatures created so far: %lu\n", sigcount);

  /* FIXME: Check whether we are really required to enter the PIN for
     each signature. There is a DO for this. */
  if (!app->did_chv1 || 1) 
    {
      char *pinvalue;

      {
        char *prompt;
        if (asprintf (&prompt, "Signature PIN [sigs done: %lu]", sigcount) < 0)
          return gpg_error_from_errno (errno);
        rc = pincb (pincb_arg, prompt, &pinvalue); 
        free (prompt);
      }
/*        pinvalue = xstrdup ("123456"); */
/*        rc = 0; */
      if (rc)
        {
          log_info ("PIN callback returned error: %s\n", gpg_strerror (rc));
          return rc;
        }

      rc = iso7816_verify (app->slot, 0x81, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV1 failed\n");
          rc = gpg_error (GPG_ERR_GENERAL);
          return rc;
        }
      app->did_chv1 = 1;
    }

  rc = iso7816_compute_ds (app->slot, data, 35, outdata, outdatalen);
  return rc;
}

/* Compute a digital signature using the INTERNAL AUTHENTICATE command
   on INDATA which is expected to be the raw message digest. For this
   application the KEYIDSTR consists of the serialnumber and the
   fingerprint delimited by a slash.

   Note that this fucntion may return the error code
   GPG_ERR_WRONG_CARD to indicate that the card currently present does
   not match the one required for the requested action (e.g. the
   serial number does not match). */
static int 
do_auth (APP app, const char *keyidstr,
         int (*pincb)(void*, const char *, char **),
         void *pincb_arg,
         const void *indata, size_t indatalen,
         unsigned char **outdata, size_t *outdatalen )
{
  int rc;
  unsigned char tmp_sn[20]; /* actually 16 but we use it also for the fpr. */
  const char *s;
  int n;
  const char *fpr = NULL;

  if (!keyidstr || !*keyidstr)
    return gpg_error (GPG_ERR_INV_VALUE);
  if (indatalen > 50) /* For a 1024 bit key. */
    return gpg_error (GPG_ERR_INV_VALUE);

  /* Check whether an OpenPGP card of any version has been requested. */
  if (strlen (keyidstr) < 32 || strncmp (keyidstr, "D27600012401", 12))
    return gpg_error (GPG_ERR_INV_ID);
  
  for (s=keyidstr, n=0; hexdigitp (s); s++, n++)
    ;
  if (n != 32)
    return gpg_error (GPG_ERR_INV_ID);
  else if (!*s)
    ; /* no fingerprint given: we allow this for now. */
  else if (*s == '/')
    fpr = s + 1; 
  else
    return gpg_error (GPG_ERR_INV_ID);

  for (s=keyidstr, n=0; n < 16; s += 2, n++)
    tmp_sn[n] = xtoi_2 (s);

  if (app->serialnolen != 16)
    return gpg_error (GPG_ERR_INV_CARD);
  if (memcmp (app->serialno, tmp_sn, 16))
    return gpg_error (GPG_ERR_WRONG_CARD);

  /* If a fingerprint has been specified check it against the one on
     the card.  This is allows for a meaningful error message in case
     the key on the card has been replaced but the shadow information
     known to gpg was not updated.  If there is no fingerprint, gpg
     will detect a bogus signature anyway due to the
     verify-after-signing feature. */
  if (fpr)
    {
      for (s=fpr, n=0; hexdigitp (s); s++, n++)
        ;
      if (n != 40)
        return gpg_error (GPG_ERR_INV_ID);
      else if (!*s)
        ; /* okay */
      else
        return gpg_error (GPG_ERR_INV_ID);

      for (s=fpr, n=0; n < 20; s += 2, n++)
        tmp_sn[n] = xtoi_2 (s);
      rc = compare_fingerprint (app, 3, tmp_sn);
      if (rc)
        return rc;
    }

  if (!app->did_chv2) 
    {
      char *pinvalue;

      rc = pincb (pincb_arg, "Authentication/Decryption PIN", &pinvalue); 
      if (rc)
        {
          log_info ("PIN callback returned error: %s\n", gpg_strerror (rc));
          return rc;
        }

      rc = iso7816_verify (app->slot, 0x82, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV2 failed\n");
          rc = gpg_error (GPG_ERR_GENERAL);
          return rc;
        }
      app->did_chv2 = 1;
    }

  rc = iso7816_internal_authenticate (app->slot, indata, indatalen,
                                      outdata, outdatalen);
  return rc;
}


static int 
do_decipher (APP app, const char *keyidstr,
             int (pincb)(void*, const char *, char **),
             void *pincb_arg,
             const void *indata, size_t indatalen,
             unsigned char **outdata, size_t *outdatalen )
{
  int rc;
  unsigned char tmp_sn[20]; /* actually 16 but we use it also for the fpr. */
  const char *s;
  int n;
  const char *fpr = NULL;

  if (!keyidstr || !*keyidstr || !indatalen)
    return gpg_error (GPG_ERR_INV_VALUE);

  /* Check whether an OpenPGP card of any version has been requested. */
  if (strlen (keyidstr) < 32 || strncmp (keyidstr, "D27600012401", 12))
    return gpg_error (GPG_ERR_INV_ID);
  
  for (s=keyidstr, n=0; hexdigitp (s); s++, n++)
    ;
  if (n != 32)
    return gpg_error (GPG_ERR_INV_ID);
  else if (!*s)
    ; /* no fingerprint given: we allow this for now. */
  else if (*s == '/')
    fpr = s + 1; 
  else
    return gpg_error (GPG_ERR_INV_ID);

  for (s=keyidstr, n=0; n < 16; s += 2, n++)
    tmp_sn[n] = xtoi_2 (s);

  if (app->serialnolen != 16)
    return gpg_error (GPG_ERR_INV_CARD);
  if (memcmp (app->serialno, tmp_sn, 16))
    return gpg_error (GPG_ERR_WRONG_CARD);

  /* If a fingerprint has been specified check it against the one on
     the card.  This is allows for a meaningful error message in case
     the key on the card has been replaced but the shadow information
     known to gpg was not updated.  If there is no fingerprint, the
     decryption will won't produce the right plaintext anyway. */
  if (fpr)
    {
      for (s=fpr, n=0; hexdigitp (s); s++, n++)
        ;
      if (n != 40)
        return gpg_error (GPG_ERR_INV_ID);
      else if (!*s)
        ; /* okay */
      else
        return gpg_error (GPG_ERR_INV_ID);

      for (s=fpr, n=0; n < 20; s += 2, n++)
        tmp_sn[n] = xtoi_2 (s);
      rc = compare_fingerprint (app, 2, tmp_sn);
      if (rc)
        return rc;
    }

  if (!app->did_chv2) 
    {
      char *pinvalue;

      rc = pincb (pincb_arg, "Decryption PIN", &pinvalue); 
/*        pinvalue = xstrdup ("123456"); */
/*        rc = 0; */
      if (rc)
        {
          log_info ("PIN callback returned error: %s\n", gpg_strerror (rc));
          return rc;
        }

      rc = iso7816_verify (app->slot, 0x82, pinvalue, strlen (pinvalue));
      xfree (pinvalue);
      if (rc)
        {
          log_error ("verify CHV2 failed\n");
          rc = gpg_error (GPG_ERR_GENERAL);
          return rc;
        }
      app->did_chv2 = 1;
    }
  
  rc = iso7816_decipher (app->slot, indata, indatalen, outdata, outdatalen);
  return rc;
}




/* Select the OpenPGP application on the card in SLOT.  This function
   must be used before any other OpenPGP application functions. */
int
app_select_openpgp (APP app, unsigned char **sn, size_t *snlen)
{
  static char const aid[] = { 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01 };
  int slot = app->slot;
  int rc;
  unsigned char *buffer;
  size_t buflen;
  
  rc = iso7816_select_application (slot, aid, sizeof aid);
  if (!rc)
    {
      /* fixme: get the full AID and check that the version is okay
         with us. */
      rc = iso7816_get_data (slot, 0x004F, &buffer, &buflen);
      if (rc)
        goto leave;
      if (opt.verbose)
        {
          log_info ("got AID: ");
          log_printhex ("", buffer, buflen);
        }

      if (sn)
        {
          *sn = buffer;
          *snlen = buflen;
          app->card_version = buffer[6] << 8;
          app->card_version |= buffer[7];
        }
      else
        xfree (buffer);

      if (opt.verbose > 1)
        dump_all_do (slot);

      app->fnc.learn_status = do_learn_status;
      app->fnc.setattr = do_setattr;
      app->fnc.genkey = do_genkey;
      app->fnc.sign = do_sign;
      app->fnc.auth = do_auth;
      app->fnc.decipher = do_decipher;
      app->fnc.change_pin = do_change_pin;
   }

leave:
  return rc;
}



/* This function is a hack to retrieve essential information about the
   card to be displayed by simple tools.  It mostly resembles what the
   LEARN command returns. All parameters return allocated strings or
   buffers or NULL if the data object is not available.  All returned
   values are sanitized. */
int
app_openpgp_cardinfo (APP app,
                      char **serialno,
                      char **disp_name,
                      char **pubkey_url,
                      unsigned char **fpr1,
                      unsigned char **fpr2,
                      unsigned char **fpr3)
{
  int rc;
  void *relptr;
  unsigned char *value;
  size_t valuelen;

  if (serialno)
    {
      time_t dummy;

      *serialno = NULL;
      rc = app_get_serial_and_stamp (app, serialno, &dummy);
      if (rc)
        {
          log_error ("error getting serial number: %s\n", gpg_strerror (rc));
          return rc;
        }
    }
      
  if (disp_name)
    {
      *disp_name = NULL;
      relptr = get_one_do (app->slot, 0x005B, &value, &valuelen);
      if (relptr)
        {
          *disp_name = make_printable_string (value, valuelen, 0);
          xfree (relptr);
        }
    }

  if (pubkey_url)
    {
      *pubkey_url = NULL;
      relptr = get_one_do (app->slot, 0x5F50, &value, &valuelen);
      if (relptr)
        {
          *pubkey_url = make_printable_string (value, valuelen, 0);
          xfree (relptr);
        }
    }

  if (fpr1)
    *fpr1 = NULL;
  if (fpr2)
    *fpr2 = NULL;
  if (fpr3)
    *fpr3 = NULL;
  relptr = get_one_do (app->slot, 0x00C5, &value, &valuelen);
  if (relptr && valuelen >= 60)
    {
      if (fpr1)
        {
          *fpr1 = xmalloc (20);
          memcpy (*fpr1, value +  0, 20);
        }
      if (fpr2)
        {
          *fpr2 = xmalloc (20);
          memcpy (*fpr2, value + 20, 20);
        }
      if (fpr3)
        {
          *fpr3 = xmalloc (20);
          memcpy (*fpr3, value + 40, 20);
        }
    }
  xfree (relptr);

  return 0;
}



/* This function is currently only used by the sc-copykeys program to
   store a key on the smartcard.  APP ist the application handle,
   KEYNO is the number of the key and PINCB, PINCB_ARG are used to ask
   for the SO PIN.  TEMPLATE and TEMPLATE_LEN describe a buffer with
   the key template to store. CREATED_AT is the timestamp used to
   create the fingerprint. M, MLEN is the RSA modulus and E, ELEN the
   RSA public exponent. This function silently overwrites an existing
   key.*/
int 
app_openpgp_storekey (APP app, int keyno,
                      unsigned char *template, size_t template_len,
                      time_t created_at,
                      const unsigned char *m, size_t mlen,
                      const unsigned char *e, size_t elen,
                      int (*pincb)(void*, const char *, char **),
                      void *pincb_arg)
{
  int rc;
  unsigned char fprbuf[20];

  if (keyno < 1 || keyno > 3)
    return gpg_error (GPG_ERR_INV_ID);
  keyno--;

  {
    char *pinvalue;
    rc = pincb (pincb_arg, "Admin PIN", &pinvalue); 
    if (rc)
      {
        log_error ("error getting PIN: %s\n", gpg_strerror (rc));
        return rc;
      }
    rc = iso7816_verify (app->slot, 0x83, pinvalue, strlen (pinvalue));
    xfree (pinvalue);
  }
  if (rc)
    {
      log_error ("verify CHV3 failed: rc=%04X\n", rc);
      goto leave;
    }

  rc = iso7816_put_data (app->slot,
                         (app->card_version > 0x0007? 0xE0 : 0xE9) + keyno,
                         template, template_len);
  if (rc)
    {
      log_error ("failed to store the key: rc=%04X\n", rc);
      rc = gpg_error (GPG_ERR_CARD);
      goto leave;
    }
 
/*    log_printhex ("RSA n:", m, mlen);  */
/*    log_printhex ("RSA e:", e, elen);  */

  rc = store_fpr (app->slot, keyno, (u32)created_at,
                  m, mlen, e, elen, fprbuf, app->card_version);

 leave:
  return rc;
}


/* Utility function for external tools: Read the public RSA key at
   KEYNO and return modulus and exponent in (M,MLEN) and (E,ELEN). */
int 
app_openpgp_readkey (APP app, int keyno, unsigned char **m, size_t *mlen,
                     unsigned char **e, size_t *elen)
{
  int rc;
  const unsigned char *keydata, *a;
  unsigned char *buffer;
  size_t buflen, keydatalen, alen;

  *m = NULL;
  *e = NULL;

  if (keyno < 1 || keyno > 3)
    return gpg_error (GPG_ERR_INV_ID);
  keyno--;

  rc = iso7816_read_public_key(app->slot, 
                               keyno == 0? "\xB6" :
                               keyno == 1? "\xB8" : "\xA4",
                               2,
                               &buffer, &buflen);
  if (rc)
    {
      rc = gpg_error (GPG_ERR_CARD);
      log_error ("reading key failed\n");
      goto leave;
    }

  keydata = find_tlv (buffer, buflen, 0x7F49, &keydatalen, 0);
  if (!keydata)
    {
      log_error ("response does not contain the public key data\n");
      rc = gpg_error (GPG_ERR_CARD);
      goto leave;
    }
 
  a = find_tlv (keydata, keydatalen, 0x0081, &alen, 0);
  if (!a)
    {
      log_error ("response does not contain the RSA modulus\n");
      rc = gpg_error (GPG_ERR_CARD);
      goto leave;
    }
  *mlen = alen;
  *m = xmalloc (alen);
  memcpy (*m, a, alen);
  
  a = find_tlv (keydata, keydatalen, 0x0082, &alen, 0);
  if (!e)
    {
      log_error ("response does not contain the RSA public exponent\n");
      rc = gpg_error (GPG_ERR_CARD);
      goto leave;
    }
  *elen = alen;
  *e = xmalloc (alen);
  memcpy (*e, a, alen);

 leave:
  xfree (buffer);
  if (rc)
    { 
      xfree (*m); *m = NULL;
      xfree (*e); *e = NULL;
    }
  return rc;
}