release/src-rt/wl/nas/mppe.c

   1 /*
   2  * Microsoft Point-to-Point Encryption Protocol (MPPE)
   3  *
   4  * Copyright (C) 2010, Broadcom Corporation
   5  * All Rights Reserved.
   6  *
   7  * This is UNPUBLISHED PROPRIETARY SOURCE CODE of Broadcom Corporation;
   8  * the contents of this file may not be disclosed to third parties, copied
   9  * or duplicated in any form, in whole or in part, without the prior
  10  * written permission of Broadcom Corporation.
  11  *
  12  * $Id: mppe.c 241388 2011-02-18 03:33:22Z stakita $
  13  */
  14
  15 #include <typedefs.h>
  16 #include <string.h>
  17 #include <bcmcrypto/md5.h>
  18
  19 #include "mppe.h"
  20
  21 #define bcopy(src, dst, len) memcpy((dst), (src), (len))
  22 #define bzero(b, len) memset((b), '\0', (len))
  23
  24 /* Encrypt or decrypt a MPPE message in place */
  25 void
  26 mppe_crypt(unsigned char salt[2],               /* 2 bytes Salt */
  27            unsigned char *text, int text_len,   /* Multiple of 16 bytes String */
  28            unsigned char *key, int key_len,     /* Shared secret */
  29            unsigned char vector[16],            /* 16 bytes Request Authenticator vector */
  30            int encrypt)                         /* Encrypt if 1 */
  31 {
  32         unsigned char b[16], c[16], *p;
  33         MD5_CTX md5;
  34         int i;
  35
  36         /* Initial cipher block is Request Authenticator vector */
  37         bcopy(vector, c, 16);
  38         for (p = text; &p[15] < &text[text_len]; p += 16) {
  39                 MD5Init(&md5);
  40                 /* Add shared secret */
  41                 MD5Update(&md5, key, key_len);
  42                 /* Add last cipher block */
  43                 MD5Update(&md5, c, 16);
  44                 /* Add salt */
  45                 if (p == text)
  46                         MD5Update(&md5, salt, 2);
  47                 MD5Final(b, &md5);
  48                 if (encrypt) {
  49                         for (i = 0; i < 16; i++) {
  50                                 p[i] ^= b[i];
  51                                 c[i] = p[i];
  52                         }
  53                 } else {
  54                         for (i = 0; i < 16; i++) {
  55                                 c[i] = p[i];
  56                                 p[i] ^= b[i];
  57                         }
  58                 }
  59         }
  60 }