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   EVP_MD_CTX *ctx;
  78
  79   ctx = EVP_MD_CTX_create();
  80   EVP_DigestInit_ex(ctx, EVP_md5(), NULL);
  81
  82   _gsskrb5_encode_om_uint32 (b->initiator_addrtype, num);
  83   EVP_DigestUpdate(ctx, num, sizeof(num));
  84   _gsskrb5_encode_om_uint32 (b->initiator_address.length, num);
  85   EVP_DigestUpdate(ctx, num, sizeof(num));
  86   if (b->initiator_address.length)
  87       EVP_DigestUpdate(ctx,
  88                        b->initiator_address.value,
  89                        b->initiator_address.length);
  90   _gsskrb5_encode_om_uint32 (b->acceptor_addrtype, num);
  91   EVP_DigestUpdate(ctx, num, sizeof(num));
  92   _gsskrb5_encode_om_uint32 (b->acceptor_address.length, num);
  93   EVP_DigestUpdate(ctx, num, sizeof(num));
  94   if (b->acceptor_address.length)
  95       EVP_DigestUpdate(ctx,
  96                        b->acceptor_address.value,
  97                        b->acceptor_address.length);
  98   _gsskrb5_encode_om_uint32 (b->application_data.length, num);
  99   EVP_DigestUpdate(ctx, num, sizeof(num));
 100   if (b->application_data.length)
 101       EVP_DigestUpdate(ctx,
 102                        b->application_data.value,
 103                        b->application_data.length);
 104   EVP_DigestFinal_ex(ctx, p, NULL);
 105   EVP_MD_CTX_destroy(ctx);
 106
 107   return 0;
 108 }
 109
 110 /*
 111  * create a checksum over the chanel bindings in
 112  * `input_chan_bindings', `flags' and `fwd_data' and return it in
 113  * `result'
 114  */
 115
 116 OM_uint32
 117 _gsskrb5_create_8003_checksum (
 118                       OM_uint32 *minor_status,
 119                       const gss_channel_bindings_t input_chan_bindings,
 120                       OM_uint32 flags,
 121                       const krb5_data *fwd_data,
 122                       Checksum *result)
 123 {
 124     u_char *p;
 125
 126     /*
 127      * see rfc1964 (section 1.1.1 (Initial Token), and the checksum value
 128      * field's format) */
 129     result->cksumtype = CKSUMTYPE_GSSAPI;
 130     if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG))
 131         result->checksum.length = 24 + 4 + fwd_data->length;
 132     else
 133         result->checksum.length = 24;
 134     result->checksum.data   = malloc (result->checksum.length);
 135     if (result->checksum.data == NULL) {
 136         *minor_status = ENOMEM;
 137         return GSS_S_FAILURE;
 138     }
 139
 140     p = result->checksum.data;
 141     _gsskrb5_encode_om_uint32 (16, p);
 142     p += 4;
 143     if (input_chan_bindings == GSS_C_NO_CHANNEL_BINDINGS) {
 144         memset (p, 0, 16);
 145     } else {
 146         hash_input_chan_bindings (input_chan_bindings, p);
 147     }
 148     p += 16;
 149     _gsskrb5_encode_om_uint32 (flags, p);
 150     p += 4;
 151
 152     if (fwd_data->length > 0 && (flags & GSS_C_DELEG_FLAG)) {
 153
 154         *p++ = (1 >> 0) & 0xFF;                   /* DlgOpt */ /* == 1 */
 155         *p++ = (1 >> 8) & 0xFF;                   /* DlgOpt */ /* == 0 */
 156         *p++ = (fwd_data->length >> 0) & 0xFF;    /* Dlgth  */
 157         *p++ = (fwd_data->length >> 8) & 0xFF;    /* Dlgth  */
 158         memcpy(p, (unsigned char *) fwd_data->data, fwd_data->length);
 159
 160         p += fwd_data->length;
 161     }
 162
 163     return GSS_S_COMPLETE;
 164 }
 165
 166 /*
 167  * verify the checksum in `cksum' over `input_chan_bindings'
 168  * returning  `flags' and `fwd_data'
 169  */
 170
 171 OM_uint32
 172 _gsskrb5_verify_8003_checksum(
 173                       OM_uint32 *minor_status,
 174                       const gss_channel_bindings_t input_chan_bindings,
 175                       const Checksum *cksum,
 176                       OM_uint32 *flags,
 177                       krb5_data *fwd_data)
 178 {
 179     unsigned char hash[16];
 180     unsigned char *p;
 181     OM_uint32 length;
 182     int DlgOpt;
 183     static unsigned char zeros[16];
 184
 185     /* XXX should handle checksums > 24 bytes */
 186     if(cksum->cksumtype != CKSUMTYPE_GSSAPI || cksum->checksum.length < 24) {
 187         *minor_status = 0;
 188         return GSS_S_BAD_BINDINGS;
 189     }
 190
 191     p = cksum->checksum.data;
 192     _gsskrb5_decode_om_uint32(p, &length);
 193     if(length != sizeof(hash)) {
 194         *minor_status = 0;
 195         return GSS_S_BAD_BINDINGS;
 196     }
 197
 198     p += 4;
 199
 200     if (input_chan_bindings != GSS_C_NO_CHANNEL_BINDINGS
 201         && memcmp(p, zeros, sizeof(zeros)) != 0) {
 202         if(hash_input_chan_bindings(input_chan_bindings, hash) != 0) {
 203             *minor_status = 0;
 204             return GSS_S_BAD_BINDINGS;
 205         }
 206         if(ct_memcmp(hash, p, sizeof(hash)) != 0) {
 207             *minor_status = 0;
 208             return GSS_S_BAD_BINDINGS;
 209         }
 210     }
 211
 212     p += sizeof(hash);
 213
 214     _gsskrb5_decode_om_uint32(p, flags);
 215     p += 4;
 216
 217     if (cksum->checksum.length > 24 && (*flags & GSS_C_DELEG_FLAG)) {
 218         if(cksum->checksum.length < 28) {
 219             *minor_status = 0;
 220             return GSS_S_BAD_BINDINGS;
 221         }
 222
 223         DlgOpt = (p[0] << 0) | (p[1] << 8);
 224         p += 2;
 225         if (DlgOpt != 1) {
 226             *minor_status = 0;
 227             return GSS_S_BAD_BINDINGS;
 228         }
 229
 230         fwd_data->length = (p[0] << 0) | (p[1] << 8);
 231         p += 2;
 232         if(cksum->checksum.length < 28 + fwd_data->length) {
 233             *minor_status = 0;
 234             return GSS_S_BAD_BINDINGS;
 235         }
 236         fwd_data->data = malloc(fwd_data->length);
 237         if (fwd_data->data == NULL) {
 238             *minor_status = ENOMEM;
 239             return GSS_S_FAILURE;
 240         }
 241         memcpy(fwd_data->data, p, fwd_data->length);
 242     }
 243
 244     return GSS_S_COMPLETE;
 245 }