stun/stunhmac.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2007 Nokia Corporation. All rights reserved.
   5  *  Contact: Rémi Denis-Courmont
   6  *
   7  * The contents of this file are subject to the Mozilla Public License Version
   8  * 1.1 (the "License"); you may not use this file except in compliance with
   9  * the License. You may obtain a copy of the License at
  10  * http://www.mozilla.org/MPL/
  11  *
  12  * Software distributed under the License is distributed on an "AS IS" basis,
  13  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  14  * for the specific language governing rights and limitations under the
  15  * License.
  16  *
  17  * The Original Code is the Nice GLib ICE library.
  18  *
  19  * The Initial Developers of the Original Code are Collabora Ltd and Nokia
  20  * Corporation. All Rights Reserved.
  21  *
  22  * Contributors:
  23  *   Rémi Denis-Courmont, Nokia
  24  *
  25  * Alternatively, the contents of this file may be used under the terms of the
  26  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  27  * case the provisions of LGPL are applicable instead of those above. If you
  28  * wish to allow use of your version of this file only under the terms of the
  29  * LGPL and not to allow others to use your version of this file under the
  30  * MPL, indicate your decision by deleting the provisions above and replace
  31  * them with the notice and other provisions required by the LGPL. If you do
  32  * not delete the provisions above, a recipient may use your version of this
  33  * file under either the MPL or the LGPL.
  34  */
  35
  36 #ifdef HAVE_CONFIG_H
  37 # include <config.h>
  38 #endif
  39
  40 #include "sha1.h"
  41 #include "md5.h"
  42 #include "rand.h"
  43
  44 #include "stunmessage.h"
  45 #include "stunhmac.h"
  46
  47 #include <string.h>
  48 #include <assert.h>
  49
  50 void stun_sha1 (const uint8_t *msg, size_t len, size_t msg_len, uint8_t *sha,
  51     const void *key, size_t keylen, int padding)
  52 {
  53   uint16_t fakelen = htons (msg_len);
  54   const uint8_t *vector[4];
  55   size_t lengths[4];
  56   uint8_t pad_char[64] = {0};
  57   size_t num_elements;
  58
  59   assert (len >= 44u);
  60
  61   vector[0] = msg;
  62   lengths[0] = 2;
  63   vector[1] = (const uint8_t *)&fakelen;
  64   lengths[1] = 2;
  65   vector[2] = msg + 4;
  66   lengths[2] = len - 28;
  67   num_elements = 3;
  68
  69   /* RFC 3489 specifies that the message's size should be 64 bytes,
  70      and \x00 padding should be done */
  71   if (padding && ((len - 24) % 64) > 0) {
  72     uint16_t pad_size = 64 - ((len - 24) % 64);
  73
  74     vector[3] = pad_char;
  75     lengths[3] = pad_size;
  76     num_elements++;
  77   }
  78
  79   hmac_sha1_vector(key, keylen, num_elements, vector, lengths, sha);
  80 }
  81
  82 static const uint8_t *priv_trim_var (const uint8_t *var, size_t *var_len)
  83 {
  84   const uint8_t *ptr = var;
  85
  86   while (*ptr == '"') {
  87     ptr++;
  88     (*var_len)--;
  89   }
  90   while(ptr[*var_len-1] == '"' ||
  91       ptr[*var_len-1] == 0) {
  92     (*var_len)--;
  93   }
  94
  95   return ptr;
  96 }
  97
  98
  99 void stun_hash_creds (const uint8_t *realm, size_t realm_len,
 100     const uint8_t *username, size_t username_len,
 101     const uint8_t *password, size_t password_len,
 102     unsigned char md5[16])
 103 {
 104   MD5_CTX ctx;
 105   const uint8_t *username_trimmed = priv_trim_var (username, &username_len);
 106   const uint8_t *password_trimmed = priv_trim_var (password, &password_len);
 107   const uint8_t *realm_trimmed = priv_trim_var (realm, &realm_len);
 108   const uint8_t *colon = (uint8_t *)":";
 109
 110   MD5Init (&ctx);
 111   MD5Update (&ctx, username_trimmed, username_len);
 112   MD5Update (&ctx, colon, 1);
 113   MD5Update (&ctx, realm_trimmed, realm_len);
 114   MD5Update (&ctx, colon, 1);
 115   MD5Update (&ctx, password_trimmed, password_len);
 116   MD5Final (md5, &ctx);
 117 }
 118
 119
 120 void stun_make_transid (StunTransactionId id)
 121 {
 122   RAND_bytes (id, 16);
 123 }