/* 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 <dlfcn.h>

#include "scdaemon.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 }
};


/* 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. */
      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 == 255)
        {
          if (n < 2)
            return NULL; /* we expected 2 more bytes with the length. */
          len = (s[0] << 8) | s[1];
          s += 2; n -= 2;
        }
      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;
    }
}



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);
    }
}


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;
    }
}


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 int n;
  unsigned char *buffer, *p;
  unsigned char fpr[20];
  int rc;
  
  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 */
  *p++ = mlen >> 8;
  *p++ = mlen;
  memcpy (p, m, mlen); p += mlen;
  *p++ = elen >> 8;
  *p++ = elen;
  memcpy (p, e, elen); p += elen;
    
  gcry_md_hash_buffer (GCRY_MD_SHA1, fpr, buffer, n+3);
  xfree (buffer);

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

  return rc;
}



/* Generate a new key on the card and store the fingerprint in the
   corresponding DO.  A KEYNUMBER of 0 creates the digital signature
   key, 1 the encryption key and 2 the authentication key.  If the key
   already exists an error is returned unless FORCE has been set to
   true.  Note, that the function does not return the public key; this
   has to be done using openpgp_readkey(). */
int
openpgp_genkey (int slot, int keynumber, int force)
{
  int rc;
  int i;
  const unsigned char *fpr;
  const unsigned char *keydata, *m, *e;
  unsigned char *buffer;
  size_t buflen, keydatalen, n, mlen, elen;
  time_t created_at;
  
  if (keynumber < 0 || keynumber > 2)
    return -1; /* invalid value */

  rc = iso7816_get_data (slot, 0x006E, &buffer, &buflen);
  if (rc)
    {
      log_error ("error reading application data\n");
      return -1;
    }
  fpr = find_tlv (buffer, buflen, 0x00C5, &n, 0);
  if (!fpr || n != 60)
    {
      log_error ("error reading fingerprint DO\n");
      goto leave;
    }
  fpr += 20*keynumber;
  for (i=0; i < 20 && !fpr[i]; i++)
    ;
  if (i!=20 && !force)
    {
      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");


  rc = iso7816_verify (slot, 0x83, "12345678", 8);
  if (rc)
    {
      log_error ("verify CHV3 failed: rc=%04X\n", rc);
      goto leave;
    }

  xfree (buffer); buffer = NULL;
  rc = iso7816_generate_keypair (slot, 
                                 keynumber == 0? "\xB6" :
                                 keynumber == 1? "\xB8" : "\xA4",
                                 2,
                                 &buffer, &buflen);
  if (rc)
    {
      log_error ("generating 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");
      goto leave;
    }
 

  m = find_tlv (keydata, keydatalen, 0x0081, &mlen, 0);
  if (!m)
    {
      log_error ("response does not contain the RSA modulus\n");
      goto leave;
    }
  log_printhex ("RSA n:", m, mlen);
  e = find_tlv (keydata, keydatalen, 0x0082, &elen, 0);
  if (!e)
    {
      log_error ("response does not contain the RSA public exponent\n");
      goto leave;
    }
  log_printhex ("RSA e:", e, elen);
  created_at = gnupg_get_time ();
  rc = store_fpr (slot, keynumber, (u32)created_at, m, mlen, e, elen);


 leave:
  xfree (buffer);
  return rc;
}


/* Select the OpenPGP application on the card in SLOT.  This function
   must be used to before any other OpenPGP application functions. */
int
app_select_openpgp (int slot)
{
  static char const aid[] = { 0xD2, 0x76, 0x00, 0x01, 0x24, 0x01 };
  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);
      xfree (buffer);

      dump_all_do (slot);

/*        rc = iso7816_verify (slot, 0x83, "12345678", 8); */
/*        if (rc) */
/*          log_error ("verify CHV3 failed: rc=%04X\n", rc); */
      

/*        rc = iso7816_put_data (slot, 0x005B, "Joe Hacker", 10); */
/*        if (rc) */
/*          log_error ("failed to set `Name': rc=%04X\n", rc); */
/*        else */
/*          dump_one_do (slot, 0x005B); */
      
      /* fixme: associate the internal state with the slot */
    }

leave:
  return rc;
}