xref: /btstack/3rd-party/lwip/core/src/netif/ppp/pppcrypt.c (revision 97dc5e692c7d94a280158af58036a0efee5b0e56)
1  /*
2   * pppcrypt.c - PPP/DES linkage for MS-CHAP and EAP SRP-SHA1
3   *
4   * Extracted from chap_ms.c by James Carlson.
5   *
6   * Copyright (c) 1995 Eric Rosenquist.  All rights reserved.
7   *
8   * Redistribution and use in source and binary forms, with or without
9   * modification, are permitted provided that the following conditions
10   * are met:
11   *
12   * 1. Redistributions of source code must retain the above copyright
13   *    notice, this list of conditions and the following disclaimer.
14   *
15   * 2. Redistributions in binary form must reproduce the above copyright
16   *    notice, this list of conditions and the following disclaimer in
17   *    the documentation and/or other materials provided with the
18   *    distribution.
19   *
20   * 3. The name(s) of the authors of this software must not be used to
21   *    endorse or promote products derived from this software without
22   *    prior written permission.
23   *
24   * THE AUTHORS OF THIS SOFTWARE DISCLAIM ALL WARRANTIES WITH REGARD TO
25   * THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
26   * AND FITNESS, IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY
27   * SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
28   * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
29   * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
30   * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
31   */
32  
33  #include "netif/ppp/ppp_opts.h"
34  #if PPP_SUPPORT && MSCHAP_SUPPORT /* don't build if not necessary */
35  
36  #include "netif/ppp/ppp_impl.h"
37  
38  #include "netif/ppp/pppcrypt.h"
39  
40  
pppcrypt_get_7bits(u_char * input,int startBit)41  static u_char pppcrypt_get_7bits(u_char *input, int startBit) {
42  	unsigned int word;
43  
44  	word  = (unsigned)input[startBit / 8] << 8;
45  	word |= (unsigned)input[startBit / 8 + 1];
46  
47  	word >>= 15 - (startBit % 8 + 7);
48  
49  	return word & 0xFE;
50  }
51  
52  /* IN  56 bit DES key missing parity bits
53   * OUT 64 bit DES key with parity bits added
54   */
pppcrypt_56_to_64_bit_key(u_char * key,u_char * des_key)55  void pppcrypt_56_to_64_bit_key(u_char *key, u_char * des_key) {
56  	des_key[0] = pppcrypt_get_7bits(key,  0);
57  	des_key[1] = pppcrypt_get_7bits(key,  7);
58  	des_key[2] = pppcrypt_get_7bits(key, 14);
59  	des_key[3] = pppcrypt_get_7bits(key, 21);
60  	des_key[4] = pppcrypt_get_7bits(key, 28);
61  	des_key[5] = pppcrypt_get_7bits(key, 35);
62  	des_key[6] = pppcrypt_get_7bits(key, 42);
63  	des_key[7] = pppcrypt_get_7bits(key, 49);
64  }
65  
66  #endif /* PPP_SUPPORT && MSCHAP_SUPPORT */
67