1 /* $NetBSD: verify_mic.c,v 1.3 2017/01/28 21:31:46 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1997 - 2003 Kungliga Tekniska Högskolan 5 * (Royal Institute of Technology, Stockholm, Sweden). 6 * 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 the 17 * documentation and/or other materials provided with the distribution. 18 * 19 * 3. Neither the name of the Institute nor the names of its contributors 20 * may be used to endorse or promote products derived from this software 21 * without specific prior written permission. 22 * 23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND 24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26 * ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE 27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33 * SUCH DAMAGE. 34 */ 35 36 #include "gsskrb5_locl.h" 37 38 #ifdef HEIM_WEAK_CRYPTO 39 40 static OM_uint32 41 verify_mic_des 42 (OM_uint32 * minor_status, 43 const gsskrb5_ctx context_handle, 44 krb5_context context, 45 const gss_buffer_t message_buffer, 46 const gss_buffer_t token_buffer, 47 gss_qop_t * qop_state, 48 krb5_keyblock *key, 49 const char *type 50 ) 51 { 52 u_char *p; 53 EVP_MD_CTX *md5; 54 u_char hash[16], *seq; 55 DES_key_schedule schedule; 56 EVP_CIPHER_CTX des_ctx; 57 DES_cblock zero; 58 DES_cblock deskey; 59 uint32_t seq_number; 60 OM_uint32 ret; 61 int cmp; 62 63 p = token_buffer->value; 64 ret = _gsskrb5_verify_header (&p, 65 token_buffer->length, 66 type, 67 GSS_KRB5_MECHANISM); 68 if (ret) 69 return ret; 70 71 if (memcmp(p, "\x00\x00", 2) != 0) 72 return GSS_S_BAD_SIG; 73 p += 2; 74 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) 75 return GSS_S_BAD_MIC; 76 p += 4; 77 p += 16; 78 79 /* verify checksum */ 80 md5 = EVP_MD_CTX_create(); 81 EVP_DigestInit_ex(md5, EVP_md5(), NULL); 82 EVP_DigestUpdate(md5, p - 24, 8); 83 EVP_DigestUpdate(md5, message_buffer->value, message_buffer->length); 84 EVP_DigestFinal_ex(md5, hash, NULL); 85 EVP_MD_CTX_destroy(md5); 86 87 memset (&zero, 0, sizeof(zero)); 88 memcpy (&deskey, key->keyvalue.data, sizeof(deskey)); 89 90 DES_set_key_unchecked (&deskey, &schedule); 91 DES_cbc_cksum ((void *)hash, (void *)hash, sizeof(hash), 92 &schedule, &zero); 93 if (ct_memcmp (p - 8, hash, 8) != 0) { 94 memset (deskey, 0, sizeof(deskey)); 95 memset (&schedule, 0, sizeof(schedule)); 96 return GSS_S_BAD_MIC; 97 } 98 99 /* verify sequence number */ 100 101 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); 102 103 p -= 16; 104 105 EVP_CIPHER_CTX_init(&des_ctx); 106 EVP_CipherInit_ex(&des_ctx, EVP_des_cbc(), NULL, key->keyvalue.data, hash, 0); 107 EVP_Cipher(&des_ctx, p, p, 8); 108 EVP_CIPHER_CTX_cleanup(&des_ctx); 109 110 memset (deskey, 0, sizeof(deskey)); 111 memset (&schedule, 0, sizeof(schedule)); 112 113 seq = p; 114 _gsskrb5_decode_om_uint32(seq, &seq_number); 115 116 if (context_handle->more_flags & LOCAL) 117 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4); 118 else 119 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4); 120 121 if (cmp != 0) { 122 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 123 return GSS_S_BAD_MIC; 124 } 125 126 ret = _gssapi_msg_order_check(context_handle->order, seq_number); 127 if (ret) { 128 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 129 return ret; 130 } 131 132 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 133 134 return GSS_S_COMPLETE; 135 } 136 #endif 137 138 static OM_uint32 139 verify_mic_des3 140 (OM_uint32 * minor_status, 141 const gsskrb5_ctx context_handle, 142 krb5_context context, 143 const gss_buffer_t message_buffer, 144 const gss_buffer_t token_buffer, 145 gss_qop_t * qop_state, 146 krb5_keyblock *key, 147 const char *type 148 ) 149 { 150 u_char *p; 151 u_char *seq; 152 uint32_t seq_number; 153 OM_uint32 ret; 154 krb5_crypto crypto; 155 krb5_data seq_data; 156 int cmp, docompat; 157 Checksum csum; 158 char *tmp; 159 char ivec[8]; 160 161 p = token_buffer->value; 162 ret = _gsskrb5_verify_header (&p, 163 token_buffer->length, 164 type, 165 GSS_KRB5_MECHANISM); 166 if (ret) 167 return ret; 168 169 if (memcmp(p, "\x04\x00", 2) != 0) /* SGN_ALG = HMAC SHA1 DES3-KD */ 170 return GSS_S_BAD_SIG; 171 p += 2; 172 if (memcmp (p, "\xff\xff\xff\xff", 4) != 0) 173 return GSS_S_BAD_MIC; 174 p += 4; 175 176 ret = krb5_crypto_init(context, key, 177 ETYPE_DES3_CBC_NONE, &crypto); 178 if (ret){ 179 *minor_status = ret; 180 return GSS_S_FAILURE; 181 } 182 183 /* verify sequence number */ 184 docompat = 0; 185 retry: 186 if (docompat) 187 memset(ivec, 0, 8); 188 else 189 memcpy(ivec, p + 8, 8); 190 191 ret = krb5_decrypt_ivec (context, 192 crypto, 193 KRB5_KU_USAGE_SEQ, 194 p, 8, &seq_data, ivec); 195 if (ret) { 196 if (docompat++) { 197 krb5_crypto_destroy (context, crypto); 198 *minor_status = ret; 199 return GSS_S_FAILURE; 200 } else 201 goto retry; 202 } 203 204 if (seq_data.length != 8) { 205 krb5_data_free (&seq_data); 206 if (docompat++) { 207 krb5_crypto_destroy (context, crypto); 208 return GSS_S_BAD_MIC; 209 } else 210 goto retry; 211 } 212 213 HEIMDAL_MUTEX_lock(&context_handle->ctx_id_mutex); 214 215 seq = seq_data.data; 216 _gsskrb5_decode_om_uint32(seq, &seq_number); 217 218 if (context_handle->more_flags & LOCAL) 219 cmp = ct_memcmp(&seq[4], "\xff\xff\xff\xff", 4); 220 else 221 cmp = ct_memcmp(&seq[4], "\x00\x00\x00\x00", 4); 222 223 krb5_data_free (&seq_data); 224 if (cmp != 0) { 225 krb5_crypto_destroy (context, crypto); 226 *minor_status = 0; 227 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 228 return GSS_S_BAD_MIC; 229 } 230 231 ret = _gssapi_msg_order_check(context_handle->order, seq_number); 232 if (ret) { 233 krb5_crypto_destroy (context, crypto); 234 *minor_status = 0; 235 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 236 return ret; 237 } 238 239 /* verify checksum */ 240 241 tmp = malloc (message_buffer->length + 8); 242 if (tmp == NULL) { 243 krb5_crypto_destroy (context, crypto); 244 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 245 *minor_status = ENOMEM; 246 return GSS_S_FAILURE; 247 } 248 249 memcpy (tmp, p - 8, 8); 250 memcpy (tmp + 8, message_buffer->value, message_buffer->length); 251 252 csum.cksumtype = CKSUMTYPE_HMAC_SHA1_DES3; 253 csum.checksum.length = 20; 254 csum.checksum.data = p + 8; 255 256 krb5_crypto_destroy (context, crypto); 257 ret = krb5_crypto_init(context, key, 258 ETYPE_DES3_CBC_SHA1, &crypto); 259 if (ret) { 260 free (tmp); 261 *minor_status = ret; 262 return GSS_S_FAILURE; 263 } 264 265 ret = krb5_verify_checksum (context, crypto, 266 KRB5_KU_USAGE_SIGN, 267 tmp, message_buffer->length + 8, 268 &csum); 269 free (tmp); 270 if (ret) { 271 krb5_crypto_destroy (context, crypto); 272 *minor_status = ret; 273 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 274 return GSS_S_BAD_MIC; 275 } 276 HEIMDAL_MUTEX_unlock(&context_handle->ctx_id_mutex); 277 278 krb5_crypto_destroy (context, crypto); 279 return GSS_S_COMPLETE; 280 } 281 282 OM_uint32 283 _gsskrb5_verify_mic_internal 284 (OM_uint32 * minor_status, 285 const gsskrb5_ctx ctx, 286 krb5_context context, 287 const gss_buffer_t message_buffer, 288 const gss_buffer_t token_buffer, 289 gss_qop_t * qop_state, 290 const char * type 291 ) 292 { 293 krb5_keyblock *key; 294 OM_uint32 ret; 295 296 if (ctx->more_flags & IS_CFX) 297 return _gssapi_verify_mic_cfx (minor_status, ctx, 298 context, message_buffer, token_buffer, 299 qop_state); 300 301 HEIMDAL_MUTEX_lock(&ctx->ctx_id_mutex); 302 ret = _gsskrb5i_get_token_key(ctx, context, &key); 303 HEIMDAL_MUTEX_unlock(&ctx->ctx_id_mutex); 304 if (ret) { 305 *minor_status = ret; 306 return GSS_S_FAILURE; 307 } 308 *minor_status = 0; 309 310 switch (key->keytype) { 311 case KRB5_ENCTYPE_DES_CBC_CRC : 312 case KRB5_ENCTYPE_DES_CBC_MD4 : 313 case KRB5_ENCTYPE_DES_CBC_MD5 : 314 #ifdef HEIM_WEAK_CRYPTO 315 ret = verify_mic_des (minor_status, ctx, context, 316 message_buffer, token_buffer, qop_state, key, 317 type); 318 #else 319 ret = GSS_S_FAILURE; 320 #endif 321 break; 322 case KRB5_ENCTYPE_DES3_CBC_MD5 : 323 case KRB5_ENCTYPE_DES3_CBC_SHA1 : 324 ret = verify_mic_des3 (minor_status, ctx, context, 325 message_buffer, token_buffer, qop_state, key, 326 type); 327 break; 328 case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5: 329 case KRB5_ENCTYPE_ARCFOUR_HMAC_MD5_56: 330 ret = _gssapi_verify_mic_arcfour (minor_status, ctx, 331 context, 332 message_buffer, token_buffer, 333 qop_state, key, type); 334 break; 335 default : 336 abort(); 337 } 338 krb5_free_keyblock (context, key); 339 340 return ret; 341 } 342 343 OM_uint32 GSSAPI_CALLCONV 344 _gsskrb5_verify_mic 345 (OM_uint32 * minor_status, 346 gss_const_ctx_id_t context_handle, 347 const gss_buffer_t message_buffer, 348 const gss_buffer_t token_buffer, 349 gss_qop_t * qop_state 350 ) 351 { 352 krb5_context context; 353 OM_uint32 ret; 354 355 GSSAPI_KRB5_INIT (&context); 356 357 if (qop_state != NULL) 358 *qop_state = GSS_C_QOP_DEFAULT; 359 360 ret = _gsskrb5_verify_mic_internal(minor_status, 361 (gsskrb5_ctx)context_handle, 362 context, 363 message_buffer, token_buffer, 364 qop_state, (void *)(intptr_t)"\x01\x01"); 365 366 return ret; 367 } 368