src/crypto/chap.c

   1 /*
   2  * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public License as
   6  * published by the Free Software Foundation; either version 2 of the
   7  * License, or any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful, but
  10  * WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA.
  18  *
  19  * You can also choose to distribute this program under the terms of
  20  * the Unmodified Binary Distribution Licence (as given in the file
  21  * COPYING.UBDL), provided that you have satisfied its requirements.
  22  */
  23
  24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  25
  26 #include <stddef.h>
  27 #include <stdlib.h>
  28 #include <string.h>
  29 #include <errno.h>
  30 #include <assert.h>
  31 #include <ipxe/crypto.h>
  32 #include <ipxe/chap.h>
  33
  34 /** @file
  35  *
  36  * CHAP protocol
  37  *
  38  */
  39
  40 /**
  41  * Initialise CHAP challenge/response
  42  *
  43  * @v chap              CHAP challenge/response
  44  * @v digest            Digest algorithm to use
  45  * @ret rc              Return status code
  46  *
  47  * Initialises a CHAP challenge/response structure.  This routine
  48  * allocates memory, and so may fail.  The allocated memory must
  49  * eventually be freed by a call to chap_finish().
  50  */
  51 int chap_init ( struct chap_response *chap,
  52                 struct digest_algorithm *digest ) {
  53         size_t state_len;
  54         void *state;
  55
  56         assert ( chap->digest == NULL );
  57         assert ( chap->digest_context == NULL );
  58         assert ( chap->response == NULL );
  59
  60         DBG ( "CHAP %p initialising with %s digest\n", chap, digest->name );
  61
  62         state_len = ( digest->ctxsize + digest->digestsize );
  63         state = malloc ( state_len );
  64         if ( ! state ) {
  65                 DBG ( "CHAP %p could not allocate %zd bytes for state\n",
  66                       chap, state_len );
  67                 return -ENOMEM;
  68         }
  69
  70         chap->digest = digest;
  71         chap->digest_context = state;
  72         chap->response = ( state + digest->ctxsize );
  73         chap->response_len = digest->digestsize;
  74         digest_init ( chap->digest, chap->digest_context );
  75         return 0;
  76 }
  77
  78 /**
  79  * Add data to the CHAP challenge
  80  *
  81  * @v chap              CHAP response
  82  * @v data              Data to add
  83  * @v len               Length of data to add
  84  */
  85 void chap_update ( struct chap_response *chap, const void *data,
  86                    size_t len ) {
  87         assert ( chap->digest != NULL );
  88         assert ( chap->digest_context != NULL );
  89
  90         if ( ! chap->digest )
  91                 return;
  92
  93         digest_update ( chap->digest, chap->digest_context, data, len );
  94 }
  95
  96 /**
  97  * Respond to the CHAP challenge
  98  *
  99  * @v chap              CHAP response
 100  *
 101  * Calculates the final CHAP response value, and places it in @c
 102  * chap->response, with a length of @c chap->response_len.
 103  */
 104 void chap_respond ( struct chap_response *chap ) {
 105         assert ( chap->digest != NULL );
 106         assert ( chap->digest_context != NULL );
 107         assert ( chap->response != NULL );
 108
 109         DBG ( "CHAP %p responding to challenge\n", chap );
 110
 111         if ( ! chap->digest )
 112                 return;
 113
 114         digest_final ( chap->digest, chap->digest_context, chap->response );
 115 }
 116
 117 /**
 118  * Free resources used by a CHAP response
 119  *
 120  * @v chap              CHAP response
 121  */
 122 void chap_finish ( struct chap_response *chap ) {
 123         void *state = chap->digest_context;
 124
 125         DBG ( "CHAP %p finished\n", chap );
 126
 127         free ( state );
 128         memset ( chap, 0, sizeof ( *chap ) );
 129 }