lwip_pppcrypt.c

00001 /*
00002  * pppcrypt.c - PPP/DES linkage for MS-CHAP and EAP SRP-SHA1
00003  *
00004  * Extracted from chap_ms.c by James Carlson.
00005  *
00006  * Copyright (c) 1995 Eric Rosenquist.  All rights reserved.
00007  *
00008  * Redistribution and use in source and binary forms, with or without
00009  * modification, are permitted provided that the following conditions
00010  * are met:
00011  *
00012  * 1. Redistributions of source code must retain the above copyright
00013  *    notice, this list of conditions and the following disclaimer.
00014  *
00015  * 2. Redistributions in binary form must reproduce the above copyright
00016  *    notice, this list of conditions and the following disclaimer in
00017  *    the documentation and/or other materials provided with the
00018  *    distribution.
00019  *
00020  * 3. The name(s) of the authors of this software must not be used to
00021  *    endorse or promote products derived from this software without
00022  *    prior written permission.
00023  *
00024  * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
00025  * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
00026  * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
00027  * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
00028  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
00029  * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
00030  * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
00031  */
00032 
00033 #include "netif/ppp/ppp_opts.h"
00034 #if PPP_SUPPORT && MSCHAP_SUPPORT /* don't build if not necessary */
00035 
00036 #include "netif/ppp/ppp_impl.h"
00037 
00038 #include "netif/ppp/pppcrypt.h"
00039 
00040 
00041 static u_char pppcrypt_get_7bits(u_char *input, int startBit) {
00042     unsigned int word;
00043 
00044     word  = (unsigned)input[startBit / 8] << 8;
00045     word |= (unsigned)input[startBit / 8 + 1];
00046 
00047     word >>= 15 - (startBit % 8 + 7);
00048 
00049     return word & 0xFE;
00050 }
00051 
00052 /* IN  56 bit DES key missing parity bits
00053  * OUT 64 bit DES key with parity bits added
00054  */
00055 void pppcrypt_56_to_64_bit_key(u_char *key, u_char * des_key) {
00056     des_key[0] = pppcrypt_get_7bits(key,  0);
00057     des_key[1] = pppcrypt_get_7bits(key,  7);
00058     des_key[2] = pppcrypt_get_7bits(key, 14);
00059     des_key[3] = pppcrypt_get_7bits(key, 21);
00060     des_key[4] = pppcrypt_get_7bits(key, 28);
00061     des_key[5] = pppcrypt_get_7bits(key, 35);
00062     des_key[6] = pppcrypt_get_7bits(key, 42);
00063     des_key[7] = pppcrypt_get_7bits(key, 49);
00064 }
00065 
00066 #endif /* PPP_SUPPORT && MSCHAP_SUPPORT */