/*
 * This is (now) gnutls_pkcs12_simple_parse() from GnuTLS 3.1, although
 * it was actually taken from parse_pkcs12() in GnuTLS 2.12.x (where it
 * was under LGPLv2.1) and modified locally. The modifications were
 * accepted back into GnuTLS in commit 9a43e8fa. Further modifications
 * by Nikos Mavrogiannopoulos are included here under LGPLv2.1 with his
 * explicit permission.
 */

#include <config.h>

#ifndef HAVE_GNUTLS_PKCS12_SIMPLE_PARSE

#include <string.h>
#include "gnutls.h"

#define opaque unsigned char
#define gnutls_assert() do {} while(0)
#define gnutls_assert_val(x) (x)

/*
 * Copyright (C) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
 * Free Software Foundation, Inc.
 *
 * Author: Nikos Mavrogiannopoulos
 *
 * This file WAS part of GnuTLS.
 *
 * The GnuTLS is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 */


/* Checks if the extra_certs contain certificates that may form a chain
 * with the first certificate in chain (it is expected that chain_len==1)
 * and appends those in the chain.
 */
static int make_chain(gnutls_x509_crt_t **chain, unsigned int *chain_len,
                      gnutls_x509_crt_t **extra_certs, unsigned int *extra_certs_len)
{
unsigned int i;

  if (*chain_len != 1)
    return gnutls_assert_val(GNUTLS_E_INVALID_REQUEST);
  
  i = 0;
  while(i<*extra_certs_len)
    {
      /* if it is an issuer but not a self-signed one */
      if (gnutls_x509_crt_check_issuer((*chain)[*chain_len - 1], (*extra_certs)[i]) != 0 &&
          gnutls_x509_crt_check_issuer((*extra_certs)[i], (*extra_certs)[i]) == 0)
        {
           void *tmp = *chain;
           *chain = gnutls_realloc (*chain, sizeof((*chain)[0]) *
                                                     ++(*chain_len));
           if (*chain == NULL)
             {
               gnutls_assert();
               gnutls_free(tmp);
               return GNUTLS_E_MEMORY_ERROR;
             }
           (*chain)[*chain_len - 1] = (*extra_certs)[i];
           
           (*extra_certs)[i] = (*extra_certs)[*extra_certs_len-1];
           (*extra_certs_len)--;

           i=0;
           continue;
        }
      i++;
    }
  return 0;
}

/**
 * gnutls_pkcs12_simple_parse:
 * @p12: the PKCS#12 blob.
 * @password: optional password used to decrypt PKCS#12 blob, bags and keys.
 * @key: a structure to store the parsed private key.
 * @chain: the corresponding to key certificate chain
 * @chain_len: will be updated with the number of additional
 * @extra_certs: optional pointer to receive an array of additional
 *                   certificates found in the PKCS#12 blob.
 * @extra_certs_len: will be updated with the number of additional
 *                       certs.
 * @crl: an optional structure to store the parsed CRL.
 * @flags: should be zero
 *
 * This function parses a PKCS#12 blob in @p12blob and extracts the
 * private key, the corresponding certificate chain, and any additional
 * certificates and a CRL.
 *
 * The @extra_certs_ret and @extra_certs_ret_len parameters are optional
 * and both may be set to %NULL. If either is non-%NULL, then both must
 * be.
 * 
 * MAC:ed PKCS#12 files are supported.  Encrypted PKCS#12 bags are
 * supported.  Encrypted PKCS#8 private keys are supported.  However,
 * only password based security, and the same password for all
 * operations, are supported.
 *
 * The private keys may be RSA PKCS#1 or DSA private keys encoded in
 * the OpenSSL way.
 *
 * PKCS#12 file may contain many keys and/or certificates, and there
 * is no way to identify which key/certificate pair you want.  You
 * should make sure the PKCS#12 file only contain one key/certificate
 * pair and/or one CRL.
 *
 * It is believed that the limitations of this function is acceptable
 * for most usage, and that any more flexibility would introduce
 * complexity that would make it harder to use this functionality at
 * all.
 *
 * If the provided structure has encrypted fields but no password
 * is provided then this function returns %GNUTLS_E_DECRYPTION_FAILED.
 *
 * Returns: On success, %GNUTLS_E_SUCCESS (0) is returned, otherwise a
 *   negative error value.
 *
 * Since: 3.1
 **/
int
gnutls_pkcs12_simple_parse (gnutls_pkcs12_t p12,
                     const char *password,
                     gnutls_x509_privkey_t * key,
                     gnutls_x509_crt_t ** chain,
                     unsigned int * chain_len,
                     gnutls_x509_crt_t ** extra_certs,
                     unsigned int * extra_certs_len,
                     gnutls_x509_crl_t * crl,
                     unsigned int flags)
{
  gnutls_pkcs12_bag_t bag = NULL;
  gnutls_x509_crt_t *_extra_certs = NULL;
  unsigned int _extra_certs_len = 0;
  gnutls_x509_crt_t *_chain = NULL;
  unsigned int _chain_len = 0;
  int idx = 0;
  int ret;
  size_t cert_id_size = 0;
  size_t key_id_size = 0;
  opaque cert_id[20];
  opaque key_id[20];
  int privkey_ok = 0;

  *key = NULL;
  
  if (crl)
    *crl = NULL;

  /* find the first private key */
  for (;;)
    {
      int elements_in_bag;
      int i;

      ret = gnutls_pkcs12_bag_init (&bag);
      if (ret < 0)
        {
          bag = NULL;
          gnutls_assert ();
          goto done;
        }

      ret = gnutls_pkcs12_get_bag (p12, idx, bag);
      if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
        break;
      if (ret < 0)
        {
          gnutls_assert ();
          goto done;
        }

      ret = gnutls_pkcs12_bag_get_type (bag, 0);
      if (ret < 0)
        {
          gnutls_assert ();
          goto done;
        }

      if (ret == GNUTLS_BAG_ENCRYPTED)
        {
          if (password == NULL)
            {
              ret = gnutls_assert_val(GNUTLS_E_DECRYPTION_FAILED);
              goto done;
            }

          ret = gnutls_pkcs12_bag_decrypt (bag, password);
          if (ret < 0)
            {
              gnutls_assert ();
              goto done;
            }
        }

      elements_in_bag = gnutls_pkcs12_bag_get_count (bag);
      if (elements_in_bag < 0)
        {
          gnutls_assert ();
          goto done;
        }

      for (i = 0; i < elements_in_bag; i++)
        {
          int type;
          gnutls_datum_t data;

          type = gnutls_pkcs12_bag_get_type (bag, i);
          if (type < 0)
            {
              gnutls_assert ();
              goto done;
            }

          ret = gnutls_pkcs12_bag_get_data (bag, i, &data);
          if (ret < 0)
            {
              gnutls_assert ();
              goto done;
            }

          switch (type)
            {
            case GNUTLS_BAG_PKCS8_ENCRYPTED_KEY:
              if (password == NULL)
                {
                  ret = gnutls_assert_val(GNUTLS_E_DECRYPTION_FAILED);
                  goto done;
                }

            case GNUTLS_BAG_PKCS8_KEY:
              if (*key != NULL) /* too simple to continue */
                {
                  gnutls_assert ();
                  break;
                }

              ret = gnutls_x509_privkey_init (key);
              if (ret < 0)
                {
                  gnutls_assert ();
                  goto done;
                }

              ret = gnutls_x509_privkey_import_pkcs8
                (*key, &data, GNUTLS_X509_FMT_DER, password,
                 type == GNUTLS_BAG_PKCS8_KEY ? GNUTLS_PKCS_PLAIN : 0);
              if (ret < 0)
                {
                  gnutls_assert ();
                  goto done;
                }

              key_id_size = sizeof (key_id);
              ret =
                gnutls_x509_privkey_get_key_id (*key, 0, key_id,
                                                &key_id_size);
              if (ret < 0)
                {
                  gnutls_assert ();
                  goto done;
                }

              privkey_ok = 1;   /* break */
              break;
            default:
              break;
            }
        }

      idx++;
      gnutls_pkcs12_bag_deinit (bag);

      if (privkey_ok != 0)      /* private key was found */
        break;
    }

  if (privkey_ok == 0)          /* no private key */
    {
      gnutls_assert ();
      return GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
    }

  /* now find the corresponding certificate 
   */
  idx = 0;
  bag = NULL;
  for (;;)
    {
      int elements_in_bag;
      int i;

      ret = gnutls_pkcs12_bag_init (&bag);
      if (ret < 0)
        {
          bag = NULL;
          gnutls_assert ();
          goto done;
        }

      ret = gnutls_pkcs12_get_bag (p12, idx, bag);
      if (ret == GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE)
        break;
      if (ret < 0)
        {
          gnutls_assert ();
          goto done;
        }

      ret = gnutls_pkcs12_bag_get_type (bag, 0);
      if (ret < 0)
        {
          gnutls_assert ();
          goto done;
        }

      if (ret == GNUTLS_BAG_ENCRYPTED)
        {
          ret = gnutls_pkcs12_bag_decrypt (bag, password);
          if (ret < 0)
            {
              gnutls_assert ();
              goto done;
            }
        }

      elements_in_bag = gnutls_pkcs12_bag_get_count (bag);
      if (elements_in_bag < 0)
        {
          gnutls_assert ();
          goto done;
        }

      for (i = 0; i < elements_in_bag; i++)
        {
          int type;
          gnutls_datum_t data;
          gnutls_x509_crt_t this_cert;

          type = gnutls_pkcs12_bag_get_type (bag, i);
          if (type < 0)
            {
              gnutls_assert ();
              goto done;
            }

          ret = gnutls_pkcs12_bag_get_data (bag, i, &data);
          if (ret < 0)
            {
              gnutls_assert ();
              goto done;
            }

          switch (type)
            {
            case GNUTLS_BAG_CERTIFICATE:
              ret = gnutls_x509_crt_init (&this_cert);
              if (ret < 0)
                {
                  gnutls_assert ();
                  goto done;
                }

              ret =
                gnutls_x509_crt_import (this_cert, &data, GNUTLS_X509_FMT_DER);
              if (ret < 0)
                {
                  gnutls_assert ();
                  gnutls_x509_crt_deinit (this_cert);
                  goto done;
                }

              /* check if the key id match */
              cert_id_size = sizeof (cert_id);
              ret =
                gnutls_x509_crt_get_key_id (this_cert, 0, cert_id, &cert_id_size);
              if (ret < 0)
                {
                  gnutls_assert ();
                  gnutls_x509_crt_deinit (this_cert);
                  goto done;
                }

              if (memcmp (cert_id, key_id, cert_id_size) != 0)
                { /* they don't match - skip the certificate */
                  if (extra_certs)
                    {
                      void *tmp = _extra_certs;
                      _extra_certs = gnutls_realloc (_extra_certs,
                                                     sizeof(_extra_certs[0]) *
                                                     ++_extra_certs_len);
                      if (!_extra_certs)
                        {
                          gnutls_assert ();
                          gnutls_free(tmp);
                          ret = GNUTLS_E_MEMORY_ERROR;
                          goto done;
                        }
                      _extra_certs[_extra_certs_len - 1] = this_cert;
                      this_cert = NULL;
                    }
                  else
                    {
                       gnutls_x509_crt_deinit (this_cert);
                    }
                }
              else
                {
                  if (_chain_len == 0)
                    {
                      _chain = gnutls_malloc (sizeof(_chain[0]) * (++_chain_len));
                      if (!_chain)
                        {
                          gnutls_assert ();
                          ret = GNUTLS_E_MEMORY_ERROR;
                          goto done;
                        }
                      _chain[_chain_len - 1] = this_cert;
                      this_cert = NULL;
                    }
                  else
                    {
                       gnutls_x509_crt_deinit (this_cert);
                    }
                }
              break;

            case GNUTLS_BAG_CRL:
              if (crl == NULL || *crl != NULL)
                {
                  gnutls_assert ();
                  break;
                }

              ret = gnutls_x509_crl_init (crl);
              if (ret < 0)
                {
                  gnutls_assert ();
                  goto done;
                }

              ret = gnutls_x509_crl_import (*crl, &data, GNUTLS_X509_FMT_DER);
              if (ret < 0)
                {
                  gnutls_assert ();
                  gnutls_x509_crl_deinit (*crl);
                  goto done;
                }
              break;

            case GNUTLS_BAG_ENCRYPTED:
              /* XXX Bother to recurse one level down?  Unlikely to
                 use the same password anyway. */
            case GNUTLS_BAG_EMPTY:
            default:
              break;
            }
        }

      idx++;
      gnutls_pkcs12_bag_deinit (bag);
    }

  if (_chain_len != 1)
    {
      ret = GNUTLS_E_REQUESTED_DATA_NOT_AVAILABLE;
      goto done;
    }

  ret = make_chain(&_chain, &_chain_len, &_extra_certs, &_extra_certs_len);
  if (ret < 0)
    {
      gnutls_assert();
      goto done;
    }

  ret = 0;

done:
  if (bag)
    gnutls_pkcs12_bag_deinit (bag);

  if (ret < 0)
    {
      if (*key)
        gnutls_x509_privkey_deinit(*key);
      if (_extra_certs_len && _extra_certs != NULL)
        {
          unsigned int i;
          for (i = 0; i < _extra_certs_len; i++)
            gnutls_x509_crt_deinit(_extra_certs[i]);
          gnutls_free(_extra_certs);
        }
      if (_chain_len && _chain != NULL)
        {
          unsigned int i;
          for (i = 0; i < _chain_len; i++)
            gnutls_x509_crt_deinit(_chain[i]);
          gnutls_free(_chain);
        }
    }
  else 
    {
      if (extra_certs) 
        {
          *extra_certs = _extra_certs;
          *extra_certs_len = _extra_certs_len;
        }
      
      *chain = _chain;
      *chain_len = _chain_len;
    }

  return ret;
}

#endif /* HAVE_GNUTLS_PKCS12_SIMPLE_PARSE */
