stun/stunhmac.c

   1 /*
   2  * This file is part of the Nice GLib ICE library.
   3  *
   4  * (C) 2008-2009 Collabora Ltd.
   5  *  Contact: Youness Alaoui
   6  * (C) 2007-2009 Nokia Corporation. All rights reserved.
   7  *  Contact: Rémi Denis-Courmont
   8  *
   9  * The contents of this file are subject to the Mozilla Public License Version
  10  * 1.1 (the "License"); you may not use this file except in compliance with
  11  * the License. You may obtain a copy of the License at
  12  * http://www.mozilla.org/MPL/
  13  *
  14  * Software distributed under the License is distributed on an "AS IS" basis,
  15  * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  16  * for the specific language governing rights and limitations under the
  17  * License.
  18  *
  19  * The Original Code is the Nice GLib ICE library.
  20  *
  21  * The Initial Developers of the Original Code are Collabora Ltd and Nokia
  22  * Corporation. All Rights Reserved.
  23  *
  24  * Contributors:
  25  *   Youness Alaoui, Collabora Ltd.
  26  *   Rémi Denis-Courmont, Nokia
  27  *
  28  * Alternatively, the contents of this file may be used under the terms of the
  29  * the GNU Lesser General Public License Version 2.1 (the "LGPL"), in which
  30  * case the provisions of LGPL are applicable instead of those above. If you
  31  * wish to allow use of your version of this file only under the terms of the
  32  * LGPL and not to allow others to use your version of this file under the
  33  * MPL, indicate your decision by deleting the provisions above and replace
  34  * them with the notice and other provisions required by the LGPL. If you do
  35  * not delete the provisions above, a recipient may use your version of this
  36  * file under either the MPL or the LGPL.
  37  */
  38
  39 #ifdef HAVE_CONFIG_H
  40 # include <config.h>
  41 #endif
  42
  43 #include "sha1.h"
  44 #include "md5.h"
  45 #include "rand.h"
  46
  47 #include "stunmessage.h"
  48 #include "stunhmac.h"
  49
  50 #include <string.h>
  51 #include <assert.h>
  52
  53 void stun_sha1 (const uint8_t *msg, size_t len, size_t msg_len, uint8_t *sha,
  54     const void *key, size_t keylen, int padding)
  55 {
  56   uint16_t fakelen = htons (msg_len);
  57   const uint8_t *vector[4];
  58   size_t lengths[4];
  59   uint8_t pad_char[64] = {0};
  60   size_t num_elements;
  61
  62   assert (len >= 44u);
  63
  64   vector[0] = msg;
  65   lengths[0] = 2;
  66   vector[1] = (const uint8_t *)&fakelen;
  67   lengths[1] = 2;
  68   vector[2] = msg + 4;
  69   lengths[2] = len - 28;
  70   num_elements = 3;
  71
  72   /* RFC 3489 specifies that the message's size should be 64 bytes,
  73      and \x00 padding should be done */
  74   if (padding && ((len - 24) % 64) > 0) {
  75     uint16_t pad_size = 64 - ((len - 24) % 64);
  76
  77     vector[3] = pad_char;
  78     lengths[3] = pad_size;
  79     num_elements++;
  80   }
  81
  82   hmac_sha1_vector(key, keylen, num_elements, vector, lengths, sha);
  83 }
  84
  85 static const uint8_t *priv_trim_var (const uint8_t *var, size_t *var_len)
  86 {
  87   const uint8_t *ptr = var;
  88
  89   while (*ptr == '"') {
  90     ptr++;
  91     (*var_len)--;
  92   }
  93   while(ptr[*var_len-1] == '"' ||
  94       ptr[*var_len-1] == 0) {
  95     (*var_len)--;
  96   }
  97
  98   return ptr;
  99 }
 100
 101
 102 void stun_hash_creds (const uint8_t *realm, size_t realm_len,
 103     const uint8_t *username, size_t username_len,
 104     const uint8_t *password, size_t password_len,
 105     unsigned char md5[16])
 106 {
 107   MD5_CTX ctx;
 108   const uint8_t *username_trimmed = priv_trim_var (username, &username_len);
 109   const uint8_t *password_trimmed = priv_trim_var (password, &password_len);
 110   const uint8_t *realm_trimmed = priv_trim_var (realm, &realm_len);
 111   const uint8_t *colon = (uint8_t *)":";
 112
 113   MD5Init (&ctx);
 114   MD5Update (&ctx, username_trimmed, username_len);
 115   MD5Update (&ctx, colon, 1);
 116   MD5Update (&ctx, realm_trimmed, realm_len);
 117   MD5Update (&ctx, colon, 1);
 118   MD5Update (&ctx, password_trimmed, password_len);
 119   MD5Final (md5, &ctx);
 120 }
 121
 122
 123 void stun_make_transid (StunTransactionId id)
 124 {
 125   RAND_bytes (id, 16);
 126 }