freebsd-dev/crypto/heimdal/kdc/kx509.c
Stanislav Sedov ae77177087 - Update FreeBSD Heimdal distribution to version 1.5.1. This also brings
several new kerberos related libraries and applications to FreeBSD:
  o kgetcred(1) allows one to manually get a ticket for a particular service.
  o kf(1) securily forwards ticket to another host through an authenticated
    and encrypted stream.
  o kcc(1) is an umbrella program around klist(1), kswitch(1), kgetcred(1)
    and other user kerberos operations. klist and kswitch are just symlinks
    to kcc(1) now.
  o kswitch(1) allows you to easily switch between kerberos credentials if
    you're running KCM.
  o hxtool(1) is a certificate management tool to use with PKINIT.
  o string2key(1) maps a password into key.
  o kdigest(8) is a userland tool to access the KDC's digest interface.
  o kimpersonate(8) creates a "fake" ticket for a service.

  We also now install manpages for some lirbaries that were not installed
  before, libheimntlm and libhx509.

- The new HEIMDAL version no longer supports Kerberos 4.  All users are
  recommended to switch to Kerberos 5.

- Weak ciphers are now disabled by default.  To enable DES support (used
  by telnet(8)), use "allow_weak_crypto" option in krb5.conf.

- libtelnet, pam_ksu and pam_krb5 are now compiled with error on warnings
  disabled due to the function they use (krb5_get_err_text(3)) being
  deprecated.  I plan to work on this next.

- Heimdal's KDC now require sqlite to operate.  We use the bundled version
  and install it as libheimsqlite.  If some other FreeBSD components will
  require it in the future we can rename it to libbsdsqlite and use for these
  components as well.

- This is not a latest Heimdal version, the new one was released while I was
  working on the update.  I will update it to 1.5.2 soon, as it fixes some
  important bugs and security issues.
2012-03-22 08:48:42 +00:00

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/*
* Copyright (c) 2006 - 2007 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "kdc_locl.h"
#include <hex.h>
#include <rfc2459_asn1.h>
#include <hx509.h>
#ifdef KX509
/*
*
*/
krb5_error_code
_kdc_try_kx509_request(void *ptr, size_t len, struct Kx509Request *req, size_t *size)
{
if (len < 4)
return -1;
if (memcmp("\x00\x00\x02\x00", ptr, 4) != 0)
return -1;
return decode_Kx509Request(((unsigned char *)ptr) + 4, len - 4, req, size);
}
/*
*
*/
static const unsigned char version_2_0[4] = {0 , 0, 2, 0};
static krb5_error_code
verify_req_hash(krb5_context context,
const Kx509Request *req,
krb5_keyblock *key)
{
unsigned char digest[SHA_DIGEST_LENGTH];
HMAC_CTX ctx;
if (req->pk_hash.length != sizeof(digest)) {
krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
"pk-hash have wrong length: %lu",
(unsigned long)req->pk_hash.length);
return KRB5KDC_ERR_PREAUTH_FAILED;
}
HMAC_CTX_init(&ctx);
HMAC_Init_ex(&ctx,
key->keyvalue.data, key->keyvalue.length,
EVP_sha1(), NULL);
if (sizeof(digest) != HMAC_size(&ctx))
krb5_abortx(context, "runtime error, hmac buffer wrong size in kx509");
HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
HMAC_Update(&ctx, req->pk_key.data, req->pk_key.length);
HMAC_Final(&ctx, digest, 0);
HMAC_CTX_cleanup(&ctx);
if (memcmp(req->pk_hash.data, digest, sizeof(digest)) != 0) {
krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
"pk-hash is not correct");
return KRB5KDC_ERR_PREAUTH_FAILED;
}
return 0;
}
static krb5_error_code
calculate_reply_hash(krb5_context context,
krb5_keyblock *key,
Kx509Response *rep)
{
krb5_error_code ret;
HMAC_CTX ctx;
HMAC_CTX_init(&ctx);
HMAC_Init_ex(&ctx, key->keyvalue.data, key->keyvalue.length,
EVP_sha1(), NULL);
ret = krb5_data_alloc(rep->hash, HMAC_size(&ctx));
if (ret) {
HMAC_CTX_cleanup(&ctx);
krb5_set_error_message(context, ENOMEM, "malloc: out of memory");
return ENOMEM;
}
HMAC_Update(&ctx, version_2_0, sizeof(version_2_0));
if (rep->error_code) {
int32_t t = *rep->error_code;
do {
unsigned char p = (t & 0xff);
HMAC_Update(&ctx, &p, 1);
t >>= 8;
} while (t);
}
if (rep->certificate)
HMAC_Update(&ctx, rep->certificate->data, rep->certificate->length);
if (rep->e_text)
HMAC_Update(&ctx, (unsigned char *)*rep->e_text, strlen(*rep->e_text));
HMAC_Final(&ctx, rep->hash->data, 0);
HMAC_CTX_cleanup(&ctx);
return 0;
}
/*
* Build a certifate for `principal´ that will expire at `endtime´.
*/
static krb5_error_code
build_certificate(krb5_context context,
krb5_kdc_configuration *config,
const krb5_data *key,
time_t endtime,
krb5_principal principal,
krb5_data *certificate)
{
hx509_ca_tbs tbs = NULL;
hx509_env env = NULL;
hx509_cert cert = NULL;
hx509_cert signer = NULL;
int ret;
if (krb5_principal_get_comp_string(context, principal, 1) != NULL) {
kdc_log(context, config, 0, "Principal is not a user");
return EINVAL;
}
ret = hx509_env_add(context->hx509ctx, &env, "principal-name",
krb5_principal_get_comp_string(context, principal, 0));
if (ret)
goto out;
{
hx509_certs certs;
hx509_query *q;
ret = hx509_certs_init(context->hx509ctx, config->kx509_ca, 0,
NULL, &certs);
if (ret) {
kdc_log(context, config, 0, "Failed to load CA %s",
config->kx509_ca);
goto out;
}
ret = hx509_query_alloc(context->hx509ctx, &q);
if (ret) {
hx509_certs_free(&certs);
goto out;
}
hx509_query_match_option(q, HX509_QUERY_OPTION_PRIVATE_KEY);
hx509_query_match_option(q, HX509_QUERY_OPTION_KU_KEYCERTSIGN);
ret = hx509_certs_find(context->hx509ctx, certs, q, &signer);
hx509_query_free(context->hx509ctx, q);
hx509_certs_free(&certs);
if (ret) {
kdc_log(context, config, 0, "Failed to find a CA in %s",
config->kx509_ca);
goto out;
}
}
ret = hx509_ca_tbs_init(context->hx509ctx, &tbs);
if (ret)
goto out;
{
SubjectPublicKeyInfo spki;
heim_any any;
memset(&spki, 0, sizeof(spki));
spki.subjectPublicKey.data = key->data;
spki.subjectPublicKey.length = key->length * 8;
ret = der_copy_oid(&asn1_oid_id_pkcs1_rsaEncryption,
&spki.algorithm.algorithm);
any.data = "\x05\x00";
any.length = 2;
spki.algorithm.parameters = &any;
ret = hx509_ca_tbs_set_spki(context->hx509ctx, tbs, &spki);
der_free_oid(&spki.algorithm.algorithm);
if (ret)
goto out;
}
{
hx509_certs certs;
hx509_cert template;
ret = hx509_certs_init(context->hx509ctx, config->kx509_template, 0,
NULL, &certs);
if (ret) {
kdc_log(context, config, 0, "Failed to load template %s",
config->kx509_template);
goto out;
}
ret = hx509_get_one_cert(context->hx509ctx, certs, &template);
hx509_certs_free(&certs);
if (ret) {
kdc_log(context, config, 0, "Failed to find template in %s",
config->kx509_template);
goto out;
}
ret = hx509_ca_tbs_set_template(context->hx509ctx, tbs,
HX509_CA_TEMPLATE_SUBJECT|
HX509_CA_TEMPLATE_KU|
HX509_CA_TEMPLATE_EKU,
template);
hx509_cert_free(template);
if (ret)
goto out;
}
hx509_ca_tbs_set_notAfter(context->hx509ctx, tbs, endtime);
hx509_ca_tbs_subject_expand(context->hx509ctx, tbs, env);
hx509_env_free(&env);
ret = hx509_ca_sign(context->hx509ctx, tbs, signer, &cert);
hx509_cert_free(signer);
if (ret)
goto out;
hx509_ca_tbs_free(&tbs);
ret = hx509_cert_binary(context->hx509ctx, cert, certificate);
hx509_cert_free(cert);
if (ret)
goto out;
return 0;
out:
if (env)
hx509_env_free(&env);
if (tbs)
hx509_ca_tbs_free(&tbs);
if (signer)
hx509_cert_free(signer);
krb5_set_error_message(context, ret, "cert creation failed");
return ret;
}
/*
*
*/
krb5_error_code
_kdc_do_kx509(krb5_context context,
krb5_kdc_configuration *config,
const struct Kx509Request *req, krb5_data *reply,
const char *from, struct sockaddr *addr)
{
krb5_error_code ret;
krb5_ticket *ticket = NULL;
krb5_flags ap_req_options;
krb5_auth_context ac = NULL;
krb5_keytab id = NULL;
krb5_principal sprincipal = NULL, cprincipal = NULL;
char *cname = NULL;
Kx509Response rep;
size_t size;
krb5_keyblock *key = NULL;
krb5_data_zero(reply);
memset(&rep, 0, sizeof(rep));
if(!config->enable_kx509) {
kdc_log(context, config, 0,
"Rejected kx509 request (disabled) from %s", from);
return KRB5KDC_ERR_POLICY;
}
kdc_log(context, config, 0, "Kx509 request from %s", from);
ret = krb5_kt_resolve(context, "HDB:", &id);
if (ret) {
kdc_log(context, config, 0, "Can't open database for digest");
goto out;
}
ret = krb5_rd_req(context,
&ac,
&req->authenticator,
NULL,
id,
&ap_req_options,
&ticket);
if (ret)
goto out;
ret = krb5_ticket_get_client(context, ticket, &cprincipal);
if (ret)
goto out;
ret = krb5_unparse_name(context, cprincipal, &cname);
if (ret)
goto out;
/* verify server principal */
ret = krb5_sname_to_principal(context, NULL, "kca_service",
KRB5_NT_UNKNOWN, &sprincipal);
if (ret)
goto out;
{
krb5_principal principal = NULL;
ret = krb5_ticket_get_server(context, ticket, &principal);
if (ret)
goto out;
ret = krb5_principal_compare(context, sprincipal, principal);
krb5_free_principal(context, principal);
if (ret != TRUE) {
char *expected, *used;
ret = krb5_unparse_name(context, sprincipal, &expected);
if (ret)
goto out;
ret = krb5_unparse_name(context, principal, &used);
if (ret) {
krb5_xfree(expected);
goto out;
}
ret = KRB5KDC_ERR_SERVER_NOMATCH;
krb5_set_error_message(context, ret,
"User %s used wrong Kx509 service "
"principal, expected: %s, used %s",
cname, expected, used);
krb5_xfree(expected);
krb5_xfree(used);
goto out;
}
}
ret = krb5_auth_con_getkey(context, ac, &key);
if (ret == 0 && key == NULL)
ret = KRB5KDC_ERR_NULL_KEY;
if (ret) {
krb5_set_error_message(context, ret, "Kx509 can't get session key");
goto out;
}
ret = verify_req_hash(context, req, key);
if (ret)
goto out;
/* Verify that the key is encoded RSA key */
{
RSAPublicKey key;
size_t size;
ret = decode_RSAPublicKey(req->pk_key.data, req->pk_key.length,
&key, &size);
if (ret)
goto out;
free_RSAPublicKey(&key);
if (size != req->pk_key.length) {
ret = ASN1_EXTRA_DATA;
goto out;
}
}
ALLOC(rep.certificate);
if (rep.certificate == NULL)
goto out;
krb5_data_zero(rep.certificate);
ALLOC(rep.hash);
if (rep.hash == NULL)
goto out;
krb5_data_zero(rep.hash);
ret = build_certificate(context, config, &req->pk_key,
krb5_ticket_get_endtime(context, ticket),
cprincipal, rep.certificate);
if (ret)
goto out;
ret = calculate_reply_hash(context, key, &rep);
if (ret)
goto out;
/*
* Encode reply, [ version | Kx509Response ]
*/
{
krb5_data data;
ASN1_MALLOC_ENCODE(Kx509Response, data.data, data.length, &rep,
&size, ret);
if (ret) {
krb5_set_error_message(context, ret, "Failed to encode kx509 reply");
goto out;
}
if (size != data.length)
krb5_abortx(context, "ASN1 internal error");
ret = krb5_data_alloc(reply, data.length + sizeof(version_2_0));
if (ret) {
free(data.data);
goto out;
}
memcpy(reply->data, version_2_0, sizeof(version_2_0));
memcpy(((unsigned char *)reply->data) + sizeof(version_2_0),
data.data, data.length);
free(data.data);
}
kdc_log(context, config, 0, "Successful Kx509 request for %s", cname);
out:
if (ac)
krb5_auth_con_free(context, ac);
if (ret)
krb5_warn(context, ret, "Kx509 request from %s failed", from);
if (ticket)
krb5_free_ticket(context, ticket);
if (id)
krb5_kt_close(context, id);
if (sprincipal)
krb5_free_principal(context, sprincipal);
if (cprincipal)
krb5_free_principal(context, cprincipal);
if (key)
krb5_free_keyblock (context, key);
if (cname)
free(cname);
free_Kx509Response(&rep);
return 0;
}
#endif /* KX509 */