lib/gnutls_psk_netconf.c

   1 /*
   2  * Copyright (C) 2008, 2010 Free Software Foundation, Inc.
   3  *
   4  * Author: Simon Josefsson
   5  *
   6  * This file is part of GnuTLS.
   7  *
   8  * The GnuTLS is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public License
  10  * as published by the Free Software Foundation; either version 2.1 of
  11  * the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful, but
  14  * WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
  21  * USA
  22  *
  23  */
  24
  25 /* Functions to support draft-ietf-netconf-tls-01.txt. */
  26
  27 #include <gnutls_int.h>
  28 #include <gnutls_hash_int.h>
  29 #include <gnutls_errors.h>
  30
  31 #ifdef ENABLE_PSK
  32
  33
  34 /**
  35  * gnutls_psk_netconf_derive_key:
  36  * @password: zero terminated string containing password.
  37  * @psk_identity: zero terminated string with PSK identity.
  38  * @psk_identity_hint: zero terminated string with PSK identity hint.
  39  * @output_key: output variable, contains newly allocated *data pointer.
  40  *
  41  * This function will derive a PSK key from a password, for use with
  42  * the Netconf protocol.
  43  *
  44  * Returns: %GNUTLS_E_SUCCESS on success, or an error code.
  45  *
  46  * Since: 2.4.0
  47  *
  48  * Deprecated: The need for this interface was dropped from the
  49  * standard on publication as a RFC.  The function works now but will
  50  * return a hard failure in a future release.
  51  */
  52 int
  53 gnutls_psk_netconf_derive_key (const char *password,
  54                                const char *psk_identity,
  55                                const char *psk_identity_hint,
  56                                gnutls_datum_t * output_key)
  57 {
  58   const char netconf_key_pad[] = "Key Pad for Netconf";
  59   size_t sha1len = _gnutls_hash_get_algo_len (GNUTLS_DIG_SHA1);
  60   size_t hintlen = strlen (psk_identity_hint);
  61   digest_hd_st dig;
  62   char *inner;
  63   size_t innerlen;
  64   int rc;
  65
  66   /*
  67    * PSK = SHA-1(SHA-1(psk_identity + "Key Pad for Netconf" + password) +
  68    *             psk_identity_hint)
  69    *
  70    */
  71
  72   rc = _gnutls_hash_init (&dig, GNUTLS_DIG_SHA1);
  73   if (rc < 0)
  74     {
  75       gnutls_assert ();
  76       return rc;
  77     }
  78
  79   rc = _gnutls_hash (&dig, psk_identity, strlen (psk_identity));
  80   if (rc < 0)
  81     {
  82       gnutls_assert ();
  83       _gnutls_hash_deinit (&dig, NULL);
  84       return rc;
  85     }
  86
  87   rc = _gnutls_hash (&dig, netconf_key_pad, strlen (netconf_key_pad));
  88   if (rc < 0)
  89     {
  90       gnutls_assert ();
  91       _gnutls_hash_deinit (&dig, NULL);
  92       return rc;
  93     }
  94
  95   rc = _gnutls_hash (&dig, password, strlen (password));
  96   if (rc < 0)
  97     {
  98       gnutls_assert ();
  99       _gnutls_hash_deinit (&dig, NULL);
 100       return rc;
 101     }
 102
 103   innerlen = sha1len + hintlen;
 104   inner = gnutls_malloc (innerlen);
 105   _gnutls_hash_deinit (&dig, inner);
 106   if (inner == NULL)
 107     {
 108       gnutls_assert ();
 109       return GNUTLS_E_MEMORY_ERROR;
 110     }
 111
 112   memcpy (inner + sha1len, psk_identity_hint, hintlen);
 113
 114   rc = _gnutls_hash_init (&dig, GNUTLS_DIG_SHA1);
 115   if (rc < 0)
 116     {
 117       gnutls_assert ();
 118       gnutls_free (inner);
 119       return rc;
 120     }
 121
 122   rc = _gnutls_hash (&dig, inner, innerlen);
 123   gnutls_free (inner);
 124   if (rc < 0)
 125     {
 126       gnutls_assert ();
 127       _gnutls_hash_deinit (&dig, NULL);
 128       return rc;
 129     }
 130
 131   output_key->data = gnutls_malloc (sha1len);
 132   _gnutls_hash_deinit (&dig, output_key->data);
 133   if (output_key->data == NULL)
 134     {
 135       gnutls_assert ();
 136       return GNUTLS_E_MEMORY_ERROR;
 137     }
 138   output_key->size = sha1len;
 139
 140   return 0;
 141 }
 142
 143 #endif /* ENABLE_PSK */