lib/gssapi/krb5/8003.c

   1 /*
   2  * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "gsskrb5_locl.h"
  35
  36 krb5_error_code
  37 _gsskrb5_encode_om_uint32(OM_uint32 n, u_char *p)
  38 {
  39   p[0] = (n >> 0)  & 0xFF;
  40   p[1] = (n >> 8)  & 0xFF;
  41   p[2] = (n >> 16) & 0xFF;
  42   p[3] = (n >> 24) & 0xFF;
  43   return 0;
  44 }
  45
  46 krb5_error_code
  47 _gsskrb5_encode_be_om_uint32(OM_uint32 n, u_char *p)
  48 {
  49   p[0] = (n >> 24) & 0xFF;
  50   p[1] = (n >> 16) & 0xFF;
  51   p[2] = (n >> 8)  & 0xFF;
  52   p[3] = (n >> 0)  & 0xFF;
  53   return 0;
  54 }
  55
  56 krb5_error_code
  57 _gsskrb5_decode_om_uint32(const void *ptr, OM_uint32 *n)
  58 {
  59     const u_char *p = ptr;
  60     *n = (p[0] << 0) | (p[1] << 8) | (p[2] << 16) | (p[3] << 24);
  61     return 0;
  62 }
  63
  64 krb5_error_code
  65 _gsskrb5_decode_be_om_uint32(const void *ptr, OM_uint32 *n)
  66 {
  67     const u_char *p = ptr;
  68     *n = (p[0] <<24) | (p[1] << 16) | (p[2] << 8) | (p[3] << 0);
  69     return 0;
  70 }
  71
  72 static krb5_error_code
  73 hash_input_chan_bindings (const gss_channel_bindings_t b,
  74                           u_char *p)
  75 {
  76   u_char num[4];
  77   MD5_CTX md5;
  78
  79   MD5_Init(&md5);
  80   _gsskrb5_encode_om_uint32 (b->initiator_addrtype, num);
  81   MD5_Update (&md5, num, sizeof(num));
  82   _gsskrb5_encode_om_uint32 (b->initiator_address.length, num);
  83   MD5_Update (&md5, num, sizeof(num));
  84   if (b->initiator_address.length)
  85     MD5_Update (&md5,
  86                 b->initiator_address.value,
  87                 b->initiator_address.length);
  88   _gsskrb5_encode_om_uint32 (b->acceptor_addrtype, num);
  89   MD5_Update (&md5, num, sizeof(num));
  90   _gsskrb5_encode_om_uint32 (b->acceptor_address.length, num);
  91   MD5_Update (&md5, num, sizeof(num));
  92   if (b->acceptor_address.length)
  93     MD5_Update (&md5,
  94                 b->acceptor_address.value,
  95                 b->acceptor_address.length);
  96   _gsskrb5_encode_om_uint32 (b->application_data.length, num);
  97   MD5_Update (&md5, num, sizeof(num));
  98   if (b->application_data.length)
  99     MD5_Update (&md5,
 100                 b->application_data.value,
 101                 b->application_data.length);
 102   MD5_Final (p, &md5);
 103   return 0;
 104 }
 105
 106 /*
 107  * create a checksum over the chanel bindings in
 108  * `input_chan_bindings', `flags' and `fwd_data' and return it in
 109  * `result'
 110  */
 111
 112 OM_uint32
 113 _gsskrb5_create_8003_checksum (
 114                       OM_uint32 *minor_status,
 115                       const gss_channel_bindings_t input_chan_bindings,
 116                       OM_uint32 flags,
 117                       const krb5_data *fwd_data,
 118                       Checksum *result)
 119 {
 120     u_char *p;
 121
 122     /*
 123      * see rfc1964 (section 1.1.1 (Initial Token), and the checksum value
 124      * field's format) */
 125     result->cksumtype = CKSUMTYPE_GSSAPI;
 126     if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG))
 127         result->checksum.length = 24 + 4 + fwd_data->length;
 128     else
 129         result->checksum.length = 24;
 130     result->checksum.data   = malloc (result->checksum.length);
 131     if (result->checksum.data == NULL) {
 132         *minor_status = ENOMEM;
 133         return GSS_S_FAILURE;
 134     }
 135
 136     p = result->checksum.data;
 137     _gsskrb5_encode_om_uint32 (16, p);
 138     p += 4;
 139     if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS) {
 140         memset (p, 0, 16);
 141     } else {
 142         hash_input_chan_bindings (input_chan_bindings, p);
 143     }
 144     p += 16;
 145     _gsskrb5_encode_om_uint32 (flags, p);
 146     p += 4;
 147
 148     if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG)) {
 149
 150         *p++ = (1 >> 0) & 0xFF;                   /* DlgOpt */ /* == 1 */
 151         *p++ = (1 >> 8) & 0xFF;                   /* DlgOpt */ /* == 0 */
 152         *p++ = (fwd_data->length >> 0) & 0xFF;    /* Dlgth  */
 153         *p++ = (fwd_data->length >> 8) & 0xFF;    /* Dlgth  */
 154         memcpy(p, (unsigned char *) fwd_data->data, fwd_data->length);
 155
 156         p += fwd_data->length;
 157     }
 158
 159     return GSS_S_COMPLETE;
 160 }
 161
 162 /*
 163  * verify the checksum in `cksum' over `input_chan_bindings'
 164  * returning  `flags' and `fwd_data'
 165  */
 166
 167 OM_uint32
 168 _gsskrb5_verify_8003_checksum(
 169                       OM_uint32 *minor_status,
 170                       const gss_channel_bindings_t input_chan_bindings,
 171                       const Checksum *cksum,
 172                       OM_uint32 *flags,
 173                       krb5_data *fwd_data)
 174 {
 175     unsigned char hash[16];
 176     unsigned char *p;
 177     OM_uint32 length;
 178     int DlgOpt;
 179     static unsigned char zeros[16];
 180
 181     if (cksum == NULL) {
 182         *minor_status = 0;
 183         return GSS_S_BAD_BINDINGS;
 184     }
 185
 186     /* XXX should handle checksums > 24 bytes */
 187     if(cksum->cksumtype != CKSUMTYPE_GSSAPI || cksum->checksum.length < 24) {
 188         *minor_status = 0;
 189         return GSS_S_BAD_BINDINGS;
 190     }
 191
 192     p = cksum->checksum.data;
 193     _gsskrb5_decode_om_uint32(p, &length);
 194     if(length != sizeof(hash)) {
 195         *minor_status = 0;
 196         return GSS_S_BAD_BINDINGS;
 197     }
 198
 199     p += 4;
 200
 201     if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS
 202         && memcmp(p, zeros, sizeof(zeros)) != 0) {
 203         if(hash_input_chan_bindings(input_chan_bindings, hash) != 0) {
 204             *minor_status = 0;
 205             return GSS_S_BAD_BINDINGS;
 206         }
 207         if(memcmp(hash, p, sizeof(hash)) != 0) {
 208             *minor_status = 0;
 209             return GSS_S_BAD_BINDINGS;
 210         }
 211     }
 212
 213     p += sizeof(hash);
 214
 215     _gsskrb5_decode_om_uint32(p, flags);
 216     p += 4;
 217
 218     if (cksum->checksum.length > 24 && (*flags & GSS_C_DELEG_FLAG)) {
 219         if(cksum->checksum.length < 28) {
 220             *minor_status = 0;
 221             return GSS_S_BAD_BINDINGS;
 222         }
 223
 224         DlgOpt = (p[0] << 0) | (p[1] << 8);
 225         p += 2;
 226         if (DlgOpt != 1) {
 227             *minor_status = 0;
 228             return GSS_S_BAD_BINDINGS;
 229         }
 230
 231         fwd_data->length = (p[0] << 0) | (p[1] << 8);
 232         p += 2;
 233         if(cksum->checksum.length < 28 + fwd_data->length) {
 234             *minor_status = 0;
 235             return GSS_S_BAD_BINDINGS;
 236         }
 237         fwd_data->data = malloc(fwd_data->length);
 238         if (fwd_data->data == NULL) {
 239             *minor_status = ENOMEM;
 240             return GSS_S_FAILURE;
 241         }
 242         memcpy(fwd_data->data, p, fwd_data->length);
 243     }
 244
 245     return GSS_S_COMPLETE;
 246 }