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 #ifdef HEIM_WEAK_CRYPTO 37 38 static OM_uint32 39 verify_mic_des 40 (OM_uint32 * minor_status, 41 const gsskrb5_ctx context_handle, 42 krb5_context context, 43 const gss_buffer_t message_buffer, 44 const gss_buffer_t token_buffer, 45 gss_qop_t * qop_state, 46 krb5_keyblock *key, 47 const char *type 48 ) 49 { 50 u_char *p; 51 EVP_MD_CTX *md5; 52 u_char hash[16], *seq; 53 DES_key_schedule schedule; 54 EVP_CIPHER_CTX *des_ctx; 55 DES_cblock zero; 56 DES_cblock deskey; 57 uint32_t seq_number; 58 OM_uint32 ret; 59 int cmp; 60 61 p = token_buffer->value; 62 ret = _gsskrb5_verify_header (&p, 63 token_buffer->length, 64 type, 65 GSS_KRB5_MECHANISM); 66 if (ret) 67 return ret; 68 69 if (memcmp(p, "\x00\x00", 2) != 0) 70 return GSS_S_BAD_SIG; 71 p += 2; 72 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) 73 return GSS_S_BAD_MIC; 74 p += 4; 75 p += 16; 76 77 /* verify checksum */ 78 md5 = EVP_MD_CTX_create(); 79 EVP_DigestInit_ex(md5, EVP_md5(), NULL); 80 EVP_DigestUpdate(md5, p - 24, 8); 81 EVP_DigestUpdate(md5, message_buffer->value, message_buffer->length); 82 EVP_DigestFinal_ex(md5, hash, NULL); 83 EVP_MD_CTX_destroy(md5); 84 85 memset (&zero, 0, sizeof(zero)); 86 memcpy (&deskey, key->keyvalue.data, sizeof(deskey)); 87 88 DES_set_key_unchecked (&deskey, &schedule); 89 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash), 90 &schedule, &zero); 91 if (ct_memcmp (p - 8, hash, 8) != 0) { 92 memset (deskey, 0, sizeof(deskey)); 93 memset (&schedule, 0, sizeof(schedule)); 94 return GSS_S_BAD_MIC; 95 } 96 97 /* verify sequence number */ 98 99 des_ctx = EVP_CIPHER_CTX_new(); 100 if (des_ctx == NULL) { 101 memset (deskey, 0, sizeof(deskey)); 102 memset (&schedule, 0, sizeof(schedule)); 103 *minor_status = ENOMEM; 104 return GSS_S_FAILURE; 105 } 106 107 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); 108 109 p -= 16; 110 111 EVP_CipherInit_ex(des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0); 112 EVP_Cipher(des_ctx, p, p, 8); 113 EVP_CIPHER_CTX_free(des_ctx); 114 115 memset (deskey, 0, sizeof(deskey)); 116 memset (&schedule, 0, sizeof(schedule)); 117 118 seq = p; 119 _gsskrb5_decode_om_uint32(seq, &seq_number); 120 121 if (context_handle->more_flags & LOCAL) 122 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4); 123 else 124 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4); 125 126 if (cmp != 0) { 127 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 128 return GSS_S_BAD_MIC; 129 } 130 131 ret = _gssapi_msg_order_check(context_handle->order, seq_number); 132 if (ret) { 133 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 134 return ret; 135 } 136 137 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 138 139 return GSS_S_COMPLETE; 140 } 141 #endif 142 143 static OM_uint32 144 verify_mic_des3 145 (OM_uint32 * minor_status, 146 const gsskrb5_ctx context_handle, 147 krb5_context context, 148 const gss_buffer_t message_buffer, 149 const gss_buffer_t token_buffer, 150 gss_qop_t * qop_state, 151 krb5_keyblock *key, 152 const char *type 153 ) 154 { 155 u_char *p; 156 u_char *seq; 157 uint32_t seq_number; 158 OM_uint32 ret; 159 krb5_crypto crypto; 160 krb5_data seq_data; 161 int cmp, docompat; 162 Checksum csum; 163 char *tmp; 164 char ivec[8]; 165 166 p = token_buffer->value; 167 ret = _gsskrb5_verify_header (&p, 168 token_buffer->length, 169 type, 170 GSS_KRB5_MECHANISM); 171 if (ret) 172 return ret; 173 174 if (memcmp(p, "\x04\x00", 2) != 0) /* SGN_ALG = HMAC SHA1 DES3-KD */ 175 return GSS_S_BAD_SIG; 176 p += 2; 177 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) 178 return GSS_S_BAD_MIC; 179 p += 4; 180 181 ret = krb5_crypto_init(context, key, 182 ETYPE_DES3_CBC_NONE, &crypto); 183 if (ret){ 184 *minor_status = ret; 185 return GSS_S_FAILURE; 186 } 187 188 /* verify sequence number */ 189 docompat = 0; 190 retry: 191 if (docompat) 192 memset(ivec, 0, 8); 193 else 194 memcpy(ivec, p + 8, 8); 195 196 ret = krb5_decrypt_ivec (context, 197 crypto, 198 KRB5_KU_USAGE_SEQ, 199 p, 8, &seq_data, ivec); 200 if (ret) { 201 if (docompat++) { 202 krb5_crypto_destroy (context, crypto); 203 *minor_status = ret; 204 return GSS_S_FAILURE; 205 } else 206 goto retry; 207 } 208 209 if (seq_data.length != 8) { 210 krb5_data_free (&seq_data); 211 if (docompat++) { 212 krb5_crypto_destroy (context, crypto); 213 return GSS_S_BAD_MIC; 214 } else 215 goto retry; 216 } 217 218 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); 219 220 seq = seq_data.data; 221 _gsskrb5_decode_om_uint32(seq, &seq_number); 222 223 if (context_handle->more_flags & LOCAL) 224 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4); 225 else 226 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4); 227 228 krb5_data_free (&seq_data); 229 if (cmp != 0) { 230 krb5_crypto_destroy (context, crypto); 231 *minor_status = 0; 232 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 233 return GSS_S_BAD_MIC; 234 } 235 236 ret = _gssapi_msg_order_check(context_handle->order, seq_number); 237 if (ret) { 238 krb5_crypto_destroy (context, crypto); 239 *minor_status = 0; 240 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 241 return ret; 242 } 243 244 /* verify checksum */ 245 246 tmp = malloc (message_buffer->length + 8); 247 if (tmp == NULL) { 248 krb5_crypto_destroy (context, crypto); 249 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 250 *minor_status = ENOMEM; 251 return GSS_S_FAILURE; 252 } 253 254 memcpy (tmp, p - 8, 8); 255 memcpy (tmp + 8, message_buffer->value, message_buffer->length); 256 257 csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3; 258 csum.checksum.length = 20; 259 csum.checksum.data = p + 8; 260 261 krb5_crypto_destroy (context, crypto); 262 ret = krb5_crypto_init(context, key, 263 ETYPE_DES3_CBC_SHA1, &crypto); 264 if (ret){ 265 *minor_status = ret; 266 return GSS_S_FAILURE; 267 } 268 269 ret = krb5_verify_checksum (context, crypto, 270 KRB5_KU_USAGE_SIGN, 271 tmp, message_buffer->length + 8, 272 &csum); 273 free (tmp); 274 if (ret) { 275 krb5_crypto_destroy (context, crypto); 276 *minor_status = ret; 277 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 278 return GSS_S_BAD_MIC; 279 } 280 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 281 282 krb5_crypto_destroy (context, crypto); 283 return GSS_S_COMPLETE; 284 } 285 286 OM_uint32 287 _gsskrb5_verify_mic_internal 288 (OM_uint32 * minor_status, 289 const gsskrb5_ctx ctx, 290 krb5_context context, 291 const gss_buffer_t message_buffer, 292 const gss_buffer_t token_buffer, 293 gss_qop_t * qop_state, 294 const char * type 295 ) 296 { 297 krb5_keyblock *key; 298 OM_uint32 ret; 299 krb5_keytype keytype; 300 301 if (ctx->more_flags & IS_CFX) 302 return _gssapi_verify_mic_cfx (minor_status, ctx, 303 context, message_buffer, token_buffer, 304 qop_state); 305 306 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex); 307 ret = _gsskrb5i_get_token_key(ctx, context, &key); 308 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex); 309 if (ret) { 310 *minor_status = ret; 311 return GSS_S_FAILURE; 312 } 313 *minor_status = 0; 314 krb5_enctype_to_keytype (context, key->keytype, &keytype); 315 switch (keytype) { 316 case KEYTYPE_DES : 317 #ifdef HEIM_WEAK_CRYPTO 318 ret = verify_mic_des (minor_status, ctx, context, 319 message_buffer, token_buffer, qop_state, key, 320 type); 321 #else 322 ret = GSS_S_FAILURE; 323 #endif 324 break; 325 case KEYTYPE_DES3 : 326 ret = verify_mic_des3 (minor_status, ctx, context, 327 message_buffer, token_buffer, qop_state, key, 328 type); 329 break; 330 case KEYTYPE_ARCFOUR : 331 case KEYTYPE_ARCFOUR_56 : 332 ret = _gssapi_verify_mic_arcfour (minor_status, ctx, 333 context, 334 message_buffer, token_buffer, 335 qop_state, key, type); 336 break; 337 default : 338 abort(); 339 } 340 krb5_free_keyblock (context, key); 341 342 return ret; 343 } 344 345 OM_uint32 GSSAPI_CALLCONV 346 _gsskrb5_verify_mic 347 (OM_uint32 * minor_status, 348 const gss_ctx_id_t context_handle, 349 const gss_buffer_t message_buffer, 350 const gss_buffer_t token_buffer, 351 gss_qop_t * qop_state 352 ) 353 { 354 krb5_context context; 355 OM_uint32 ret; 356 357 GSSAPI_KRB5_INIT (&context); 358 359 if (qop_state != NULL) 360 *qop_state = GSS_C_QOP_DEFAULT; 361 362 ret = _gsskrb5_verify_mic_internal(minor_status, 363 (gsskrb5_ctx)context_handle, 364 context, 365 message_buffer, token_buffer, 366 qop_state, (void *)(intptr_t)"\x01\x01"); 367 368 return ret; 369 } 370