2 * Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
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7 * modification, are permitted provided that the following conditions
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36 #include <rfc2459_asn1.h>
46 _kdc_try_kx509_request(void *ptr, size_t len, struct 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_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
71 "pk-hash have wrong length: %lu",
72 (unsigned long)req->pk_hash.length);
73 return KRB5KDC_ERR_PREAUTH_FAILED;
78 krb5_set_error_message(context, ENOMEM,
79 "HMAC context malloc failed");
83 key->keyvalue.data, key->keyvalue.length,
85 if (sizeof(digest) != HMAC_size(ctx))
86 krb5_abortx(context, "runtime error, hmac buffer wrong size in kx509");
87 HMAC_Update(ctx, version_2_0, sizeof(version_2_0));
88 HMAC_Update(ctx, req->pk_key.data, req->pk_key.length);
89 HMAC_Final(ctx, digest, 0);
92 if (memcmp(req->pk_hash.data, digest, sizeof(digest)) != 0) {
93 krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
94 "pk-hash is not correct");
95 return KRB5KDC_ERR_PREAUTH_FAILED;
100 static krb5_error_code
101 calculate_reply_hash(krb5_context context,
108 ctx = HMAC_CTX_new();
110 krb5_set_error_message(context, ENOMEM,
111 "HMAC context malloc failed");
115 HMAC_Init_ex(ctx, key->keyvalue.data, key->keyvalue.length,
117 ret = krb5_data_alloc(rep->hash, HMAC_size(ctx));
120 krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
124 HMAC_Update(ctx, version_2_0, sizeof(version_2_0));
125 if (rep->error_code) {
126 int32_t t = *rep->error_code;
128 unsigned char p = (t & 0xff);
129 HMAC_Update(ctx, &p, 1);
133 if (rep->certificate)
134 HMAC_Update(ctx, rep->certificate->data, rep->certificate->length);
136 HMAC_Update(ctx, (unsigned char *)*rep->e_text, strlen(*rep->e_text));
138 HMAC_Final(ctx, rep->hash->data, 0);
145 * Build a certifate for `principal´ that will expire at `endtime´.
148 static krb5_error_code
149 build_certificate(krb5_context context,
150 krb5_kdc_configuration *config,
151 const krb5_data *key,
153 krb5_principal principal,
154 krb5_data *certificate)
156 hx509_ca_tbs tbs = NULL;
157 hx509_env env = NULL;
158 hx509_cert cert = NULL;
159 hx509_cert signer = NULL;
162 if (krb5_principal_get_comp_string(context, principal, 1) != NULL) {
163 kdc_log(context, config, 0, "Principal is not a user");
167 ret = hx509_env_add(context->hx509ctx, &env, "principal-name",
168 krb5_principal_get_comp_string(context, principal, 0));
176 ret = hx509_certs_init(context->hx509ctx, config->kx509_ca, 0,
179 kdc_log(context, config, 0, "Failed to load CA %s",
183 ret = hx509_query_alloc(context->hx509ctx, &q);
185 hx509_certs_free(&certs);
189 hx509_query_match_option(q, HX509_QUERY_OPTION_PRIVATE_KEY);
190 hx509_query_match_option(q, HX509_QUERY_OPTION_KU_KEYCERTSIGN);
192 ret = hx509_certs_find(context->hx509ctx, certs, q, &signer);
193 hx509_query_free(context->hx509ctx, q);
194 hx509_certs_free(&certs);
196 kdc_log(context, config, 0, "Failed to find a CA in %s",
202 ret = hx509_ca_tbs_init(context->hx509ctx, &tbs);
207 SubjectPublicKeyInfo spki;
210 memset(&spki, 0, sizeof(spki));
212 spki.subjectPublicKey.data = key->data;
213 spki.subjectPublicKey.length = key->length * 8;
215 ret = der_copy_oid(&asn1_oid_id_pkcs1_rsaEncryption,
216 &spki.algorithm.algorithm);
218 any.data = "\x05\x00";
220 spki.algorithm.parameters = &any;
222 ret = hx509_ca_tbs_set_spki(context->hx509ctx, tbs, &spki);
223 der_free_oid(&spki.algorithm.algorithm);
232 ret = hx509_certs_init(context->hx509ctx, config->kx509_template, 0,
235 kdc_log(context, config, 0, "Failed to load template %s",
236 config->kx509_template);
239 ret = hx509_get_one_cert(context->hx509ctx, certs, &template);
240 hx509_certs_free(&certs);
242 kdc_log(context, config, 0, "Failed to find template in %s",
243 config->kx509_template);
246 ret = hx509_ca_tbs_set_template(context->hx509ctx, tbs,
247 HX509_CA_TEMPLATE_SUBJECT|
248 HX509_CA_TEMPLATE_KU|
249 HX509_CA_TEMPLATE_EKU,
251 hx509_cert_free(template);
256 hx509_ca_tbs_set_notAfter(context->hx509ctx, tbs, endtime);
258 hx509_ca_tbs_subject_expand(context->hx509ctx, tbs, env);
259 hx509_env_free(&env);
261 ret = hx509_ca_sign(context->hx509ctx, tbs, signer, &cert);
262 hx509_cert_free(signer);
266 hx509_ca_tbs_free(&tbs);
268 ret = hx509_cert_binary(context->hx509ctx, cert, certificate);
269 hx509_cert_free(cert);
276 hx509_env_free(&env);
278 hx509_ca_tbs_free(&tbs);
280 hx509_cert_free(signer);
281 krb5_set_error_message(context, ret, "cert creation failed");
290 _kdc_do_kx509(krb5_context context,
291 krb5_kdc_configuration *config,
292 const struct Kx509Request *req, krb5_data *reply,
293 const char *from, struct sockaddr *addr)
296 krb5_ticket *ticket = NULL;
297 krb5_flags ap_req_options;
298 krb5_auth_context ac = NULL;
299 krb5_keytab id = NULL;
300 krb5_principal sprincipal = NULL, cprincipal = NULL;
304 krb5_keyblock *key = NULL;
306 krb5_data_zero(reply);
307 memset(&rep, 0, sizeof(rep));
309 if(!config->enable_kx509) {
310 kdc_log(context, config, 0,
311 "Rejected kx509 request (disabled) from %s", from);
312 return KRB5KDC_ERR_POLICY;
315 kdc_log(context, config, 0, "Kx509 request from %s", from);
317 ret = krb5_kt_resolve(context, "HDB:", &id);
319 kdc_log(context, config, 0, "Can't open database for digest");
323 ret = krb5_rd_req(context,
333 ret = krb5_ticket_get_client(context, ticket, &cprincipal);
337 ret = krb5_unparse_name(context, cprincipal, &cname);
341 /* verify server principal */
343 ret = krb5_sname_to_principal(context, NULL, "kca_service",
344 KRB5_NT_UNKNOWN, &sprincipal);
349 krb5_principal principal = NULL;
351 ret = krb5_ticket_get_server(context, ticket, &principal);
355 ret = krb5_principal_compare(context, sprincipal, principal);
356 krb5_free_principal(context, principal);
358 char *expected, *used;
360 ret = krb5_unparse_name(context, sprincipal, &expected);
363 ret = krb5_unparse_name(context, principal, &used);
365 krb5_xfree(expected);
369 ret = KRB5KDC_ERR_SERVER_NOMATCH;
370 krb5_set_error_message(context, ret,
371 "User %s used wrong Kx509 service "
372 "principal, expected: %s, used %s",
373 cname, expected, used);
374 krb5_xfree(expected);
380 ret = krb5_auth_con_getkey(context, ac, &key);
381 if (ret == 0 && key == NULL)
382 ret = KRB5KDC_ERR_NULL_KEY;
384 krb5_set_error_message(context, ret, "Kx509 can't get session key");
388 ret = verify_req_hash(context, req, key);
392 /* Verify that the key is encoded RSA key */
397 ret = decode_RSAPublicKey(req->pk_key.data, req->pk_key.length,
401 free_RSAPublicKey(&key);
402 if (size != req->pk_key.length) {
403 ret = ASN1_EXTRA_DATA;
408 ALLOC(rep.certificate);
409 if (rep.certificate == NULL)
411 krb5_data_zero(rep.certificate);
413 if (rep.hash == NULL)
415 krb5_data_zero(rep.hash);
417 ret = build_certificate(context, config, &req->pk_key,
418 krb5_ticket_get_endtime(context, ticket),
419 cprincipal, rep.certificate);
423 ret = calculate_reply_hash(context, key, &rep);
428 * Encode reply, [ version | Kx509Response ]
434 ASN1_MALLOC_ENCODE(Kx509Response, data.data, data.length, &rep,
437 krb5_set_error_message(context, ret, "Failed to encode kx509 reply");
440 if (size != data.length)
441 krb5_abortx(context, "ASN1 internal error");
443 ret = krb5_data_alloc(reply, data.length + sizeof(version_2_0));
448 memcpy(reply->data, version_2_0, sizeof(version_2_0));
449 memcpy(((unsigned char *)reply->data) + sizeof(version_2_0),
450 data.data, data.length);
454 kdc_log(context, config, 0, "Successful Kx509 request for %s", cname);
458 krb5_auth_con_free(context, ac);
460 krb5_warn(context, ret, "Kx509 request from %s failed", from);
462 krb5_free_ticket(context, ticket);
464 krb5_kt_close(context, id);
466 krb5_free_principal(context, sprincipal);
468 krb5_free_principal(context, cprincipal);
470 krb5_free_keyblock (context, key);
473 free_Kx509Response(&rep);