workbench/network/WirelessManager/src/crypto/md5.c

   1 /*
   2  * MD5 hash implementation and interface functions
   3  * Copyright (c) 2003-2005, Jouni Malinen <j@w1.fi>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * Alternatively, this software may be distributed under the terms of BSD
  10  * license.
  11  *
  12  * See README and COPYING for more details.
  13  */
  14
  15 #include "includes.h"
  16
  17 #include "common.h"
  18 #include "md5.h"
  19 #include "crypto.h"
  20
  21
  22 /**
  23  * hmac_md5_vector - HMAC-MD5 over data vector (RFC 2104)
  24  * @key: Key for HMAC operations
  25  * @key_len: Length of the key in bytes
  26  * @num_elem: Number of elements in the data vector
  27  * @addr: Pointers to the data areas
  28  * @len: Lengths of the data blocks
  29  * @mac: Buffer for the hash (16 bytes)
  30  * Returns: 0 on success, -1 on failure
  31  */
  32 int hmac_md5_vector(const u8 *key, size_t key_len, size_t num_elem,
  33                     const u8 *addr[], const size_t *len, u8 *mac)
  34 {
  35         u8 k_pad[64]; /* padding - key XORd with ipad/opad */
  36         u8 tk[16];
  37         const u8 *_addr[6];
  38         size_t i, _len[6];
  39
  40         if (num_elem > 5) {
  41                 /*
  42                  * Fixed limit on the number of fragments to avoid having to
  43                  * allocate memory (which could fail).
  44                  */
  45                 return -1;
  46         }
  47
  48         /* if key is longer than 64 bytes reset it to key = MD5(key) */
  49         if (key_len > 64) {
  50                 if (md5_vector(1, &key, &key_len, tk))
  51                         return -1;
  52                 key = tk;
  53                 key_len = 16;
  54         }
  55
  56         /* the HMAC_MD5 transform looks like:
  57          *
  58          * MD5(K XOR opad, MD5(K XOR ipad, text))
  59          *
  60          * where K is an n byte key
  61          * ipad is the byte 0x36 repeated 64 times
  62          * opad is the byte 0x5c repeated 64 times
  63          * and text is the data being protected */
  64
  65         /* start out by storing key in ipad */
  66         os_memset(k_pad, 0, sizeof(k_pad));
  67         os_memcpy(k_pad, key, key_len);
  68
  69         /* XOR key with ipad values */
  70         for (i = 0; i < 64; i++)
  71                 k_pad[i] ^= 0x36;
  72
  73         /* perform inner MD5 */
  74         _addr[0] = k_pad;
  75         _len[0] = 64;
  76         for (i = 0; i < num_elem; i++) {
  77                 _addr[i + 1] = addr[i];
  78                 _len[i + 1] = len[i];
  79         }
  80         if (md5_vector(1 + num_elem, _addr, _len, mac))
  81                 return -1;
  82
  83         os_memset(k_pad, 0, sizeof(k_pad));
  84         os_memcpy(k_pad, key, key_len);
  85         /* XOR key with opad values */
  86         for (i = 0; i < 64; i++)
  87                 k_pad[i] ^= 0x5c;
  88
  89         /* perform outer MD5 */
  90         _addr[0] = k_pad;
  91         _len[0] = 64;
  92         _addr[1] = mac;
  93         _len[1] = MD5_MAC_LEN;
  94         return md5_vector(2, _addr, _len, mac);
  95 }
  96
  97
  98 /**
  99  * hmac_md5 - HMAC-MD5 over data buffer (RFC 2104)
 100  * @key: Key for HMAC operations
 101  * @key_len: Length of the key in bytes
 102  * @data: Pointers to the data area
 103  * @data_len: Length of the data area
 104  * @mac: Buffer for the hash (16 bytes)
 105  * Returns: 0 on success, -1 on failure
 106  */
 107 int hmac_md5(const u8 *key, size_t key_len, const u8 *data, size_t data_len,
 108               u8 *mac)
 109 {
 110         return hmac_md5_vector(key, key_len, 1, &data, &data_len, mac);
 111 }