2 * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
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36 #include <rfc2459_asn1.h>
39 RCSID("$Id: kx509.c 21607 2007-07-17 07:04:52Z lha $");
46 _kdc_try_kx509_request(void *ptr, size_t len, Kx509Request *req, size_t *size)
50 if (memcmp("\x00\x00\x02\x00", ptr, 4) != 0)
52 return decode_Kx509Request(((unsigned char *)ptr) + 4, len - 4, req, size);
59 static const unsigned char version_2_0[4] = {0 , 0, 2, 0};
61 static krb5_error_code
62 verify_req_hash(krb5_context context,
63 const Kx509Request *req,
66 unsigned char digest[SHA_DIGEST_LENGTH];
69 if (req->pk_hash.length != sizeof(digest)) {
70 krb5_set_error_string(context, "pk-hash have wrong length: %lu",
71 (unsigned long)req->pk_hash.length);
72 return KRB5KDC_ERR_PREAUTH_FAILED;
77 key->keyvalue.data, key->keyvalue.length,
79 if (sizeof(digest) != HMAC_size(&ctx))
80 krb5_abortx(context, "runtime error, hmac buffer wrong size in kx509");
81 HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
82 HMAC_Update(&ctx, req->pk_key.data, req->pk_key.length);
83 HMAC_Final(&ctx, digest, 0);
84 HMAC_CTX_cleanup(&ctx);
86 if (memcmp(req->pk_hash.data, digest, sizeof(digest)) != 0) {
87 krb5_set_error_string(context, "pk-hash is not correct");
88 return KRB5KDC_ERR_PREAUTH_FAILED;
93 static krb5_error_code
94 calculate_reply_hash(krb5_context context,
103 key->keyvalue.data, key->keyvalue.length,
105 rep->hash->length = HMAC_size(&ctx);
106 rep->hash->data = malloc(rep->hash->length);
107 if (rep->hash->data == NULL) {
108 HMAC_CTX_cleanup(&ctx);
109 krb5_set_error_string(context, "out of memory");
113 HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
114 if (rep->error_code) {
115 int32_t t = *rep->error_code;
117 unsigned char p = (t & 0xff);
118 HMAC_Update(&ctx, &p, 1);
122 if (rep->certificate)
123 HMAC_Update(&ctx, rep->certificate->data, rep->certificate->length);
125 HMAC_Update(&ctx, (unsigned char *)*rep->e_text, strlen(*rep->e_text));
127 HMAC_Final(&ctx, rep->hash->data, 0);
128 HMAC_CTX_cleanup(&ctx);
134 * Build a certifate for `principal´ that will expire at `endtime´.
137 static krb5_error_code
138 build_certificate(krb5_context context,
139 krb5_kdc_configuration *config,
140 const krb5_data *key,
142 krb5_principal principal,
143 krb5_data *certificate)
145 hx509_context hxctx = NULL;
146 hx509_ca_tbs tbs = NULL;
147 hx509_env env = NULL;
148 hx509_cert cert = NULL;
149 hx509_cert signer = NULL;
152 if (krb5_principal_get_comp_string(context, principal, 1) != NULL) {
153 kdc_log(context, config, 0, "Principal is not a user");
157 ret = hx509_context_init(&hxctx);
161 ret = hx509_env_init(hxctx, &env);
165 ret = hx509_env_add(hxctx, env, "principal-name",
166 krb5_principal_get_comp_string(context, principal, 0));
174 ret = hx509_certs_init(hxctx, config->kx509_ca, 0,
177 kdc_log(context, config, 0, "Failed to load CA %s",
181 ret = hx509_query_alloc(hxctx, &q);
183 hx509_certs_free(&certs);
187 hx509_query_match_option(q, HX509_QUERY_OPTION_PRIVATE_KEY);
188 hx509_query_match_option(q, HX509_QUERY_OPTION_KU_KEYCERTSIGN);
190 ret = hx509_certs_find(hxctx, certs, q, &signer);
191 hx509_query_free(hxctx, q);
192 hx509_certs_free(&certs);
194 kdc_log(context, config, 0, "Failed to find a CA in %s",
200 ret = hx509_ca_tbs_init(hxctx, &tbs);
205 SubjectPublicKeyInfo spki;
208 memset(&spki, 0, sizeof(spki));
210 spki.subjectPublicKey.data = key->data;
211 spki.subjectPublicKey.length = key->length * 8;
213 ret = der_copy_oid(oid_id_pkcs1_rsaEncryption(),
214 &spki.algorithm.algorithm);
216 any.data = "\x05\x00";
218 spki.algorithm.parameters = &any;
220 ret = hx509_ca_tbs_set_spki(hxctx, tbs, &spki);
221 der_free_oid(&spki.algorithm.algorithm);
230 ret = hx509_certs_init(hxctx, config->kx509_template, 0,
233 kdc_log(context, config, 0, "Failed to load template %s",
234 config->kx509_template);
237 ret = hx509_get_one_cert(hxctx, certs, &template);
238 hx509_certs_free(&certs);
240 kdc_log(context, config, 0, "Failed to find template in %s",
241 config->kx509_template);
244 ret = hx509_ca_tbs_set_template(hxctx, tbs,
245 HX509_CA_TEMPLATE_SUBJECT|
246 HX509_CA_TEMPLATE_KU|
247 HX509_CA_TEMPLATE_EKU,
249 hx509_cert_free(template);
254 hx509_ca_tbs_set_notAfter(hxctx, tbs, endtime);
256 hx509_ca_tbs_subject_expand(hxctx, tbs, env);
257 hx509_env_free(&env);
259 ret = hx509_ca_sign(hxctx, tbs, signer, &cert);
260 hx509_cert_free(signer);
264 hx509_ca_tbs_free(&tbs);
266 ret = hx509_cert_binary(hxctx, cert, certificate);
267 hx509_cert_free(cert);
271 hx509_context_free(&hxctx);
276 hx509_env_free(&env);
278 hx509_ca_tbs_free(&tbs);
280 hx509_cert_free(signer);
282 hx509_context_free(&hxctx);
283 krb5_set_error_string(context, "cert creation failed");
292 _kdc_do_kx509(krb5_context context,
293 krb5_kdc_configuration *config,
294 const Kx509Request *req, krb5_data *reply,
295 const char *from, struct sockaddr *addr)
298 krb5_ticket *ticket = NULL;
299 krb5_flags ap_req_options;
300 krb5_auth_context ac = NULL;
301 krb5_keytab id = NULL;
302 krb5_principal sprincipal = NULL, cprincipal = NULL;
306 krb5_keyblock *key = NULL;
308 krb5_data_zero(reply);
309 memset(&rep, 0, sizeof(rep));
311 if(!config->enable_kx509) {
312 kdc_log(context, config, 0,
313 "Rejected kx509 request (disabled) from %s", from);
314 return KRB5KDC_ERR_POLICY;
317 kdc_log(context, config, 0, "Kx509 request from %s", from);
319 ret = krb5_kt_resolve(context, "HDB:", &id);
321 kdc_log(context, config, 0, "Can't open database for digest");
325 ret = krb5_rd_req(context,
335 ret = krb5_ticket_get_client(context, ticket, &cprincipal);
339 ret = krb5_unparse_name(context, cprincipal, &cname);
343 /* verify server principal */
345 ret = krb5_sname_to_principal(context, NULL, "kca_service",
346 KRB5_NT_UNKNOWN, &sprincipal);
351 krb5_principal principal = NULL;
353 ret = krb5_ticket_get_server(context, ticket, &principal);
357 ret = krb5_principal_compare(context, sprincipal, principal);
358 krb5_free_principal(context, principal);
360 ret = KRB5KDC_ERR_SERVER_NOMATCH;
361 krb5_set_error_string(context,
362 "User %s used wrong Kx509 service principal",
368 ret = krb5_auth_con_getkey(context, ac, &key);
369 if (ret || key == NULL) {
370 krb5_set_error_string(context, "Kx509 can't get session key");
374 ret = verify_req_hash(context, req, key);
378 /* Verify that the key is encoded RSA key */
383 ret = decode_RSAPublicKey(req->pk_key.data, req->pk_key.length,
387 free_RSAPublicKey(&key);
388 if (size != req->pk_key.length)
392 ALLOC(rep.certificate);
393 if (rep.certificate == NULL)
395 krb5_data_zero(rep.certificate);
397 if (rep.hash == NULL)
399 krb5_data_zero(rep.hash);
401 ret = build_certificate(context, config, &req->pk_key,
402 krb5_ticket_get_endtime(context, ticket),
403 cprincipal, rep.certificate);
407 ret = calculate_reply_hash(context, key, &rep);
412 * Encode reply, [ version | Kx509Response ]
418 ASN1_MALLOC_ENCODE(Kx509Response, data.data, data.length, &rep,
421 krb5_set_error_string(context, "Failed to encode kx509 reply");
424 if (size != data.length)
425 krb5_abortx(context, "ASN1 internal error");
427 ret = krb5_data_alloc(reply, data.length + sizeof(version_2_0));
432 memcpy(reply->data, version_2_0, sizeof(version_2_0));
433 memcpy(((unsigned char *)reply->data) + sizeof(version_2_0),
434 data.data, data.length);
438 kdc_log(context, config, 0, "Successful Kx509 request for %s", cname);
442 krb5_auth_con_free(context, ac);
444 krb5_warn(context, ret, "Kx509 request from %s failed", from);
446 krb5_free_ticket(context, ticket);
448 krb5_kt_close(context, id);
450 krb5_free_principal(context, sprincipal);
452 krb5_free_principal(context, cprincipal);
454 krb5_free_keyblock (context, key);
457 free_Kx509Response(&rep);