diff options
Diffstat (limited to 'src/kdc/do_tgs_req.c')
| -rw-r--r-- | src/kdc/do_tgs_req.c | 1296 |
1 files changed, 1296 insertions, 0 deletions
diff --git a/src/kdc/do_tgs_req.c b/src/kdc/do_tgs_req.c new file mode 100644 index 000000000000..547a41441767 --- /dev/null +++ b/src/kdc/do_tgs_req.c @@ -0,0 +1,1296 @@ +/* -*- mode: c; c-basic-offset: 4; indent-tabs-mode: nil -*- */ +/* kdc/do_tgs_req.c - KDC Routines to deal with TGS_REQ's */ +/* + * Copyright 1990, 1991, 2001, 2007, 2008, 2009, 2013, 2014 by the + * Massachusetts Institute of Technology. All Rights Reserved. + * + * Export of this software from the United States of America may + * require a specific license from the United States Government. + * It is the responsibility of any person or organization contemplating + * export to obtain such a license before exporting. + * + * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and + * distribute this software and its documentation for any purpose and + * without fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright notice and + * this permission notice appear in supporting documentation, and that + * the name of M.I.T. not be used in advertising or publicity pertaining + * to distribution of the software without specific, written prior + * permission. Furthermore if you modify this software you must label + * your software as modified software and not distribute it in such a + * fashion that it might be confused with the original M.I.T. software. + * M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" without express + * or implied warranty. + */ +/* + * Copyright (c) 2006-2008, Novell, Inc. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions are met: + * + * * Redistributions of source code must retain the above copyright notice, + * this list of conditions and the following disclaimer. + * * 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. + * * The copyright holder's name is not used to endorse or promote products + * derived from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 COPYRIGHT OWNER 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 "k5-int.h" + +#include <syslog.h> +#ifdef HAVE_NETINET_IN_H +#include <sys/types.h> +#include <netinet/in.h> +#ifndef hpux +#include <arpa/inet.h> +#endif +#endif + +#include "kdc_util.h" +#include "kdc_audit.h" +#include "policy.h" +#include "extern.h" +#include "adm_proto.h" +#include <ctype.h> + +static krb5_error_code +find_alternate_tgs(kdc_realm_t *, krb5_principal, krb5_db_entry **, + const char**); + +static krb5_error_code +prepare_error_tgs(struct kdc_request_state *, krb5_kdc_req *,krb5_ticket *,int, + krb5_principal,krb5_data **,const char *, krb5_pa_data **); + +static krb5_error_code +decrypt_2ndtkt(kdc_realm_t *, krb5_kdc_req *, krb5_flags, krb5_db_entry **, + const char **); + +static krb5_error_code +gen_session_key(kdc_realm_t *, krb5_kdc_req *, krb5_db_entry *, + krb5_keyblock *, const char **); + +static krb5_int32 +find_referral_tgs(kdc_realm_t *, krb5_kdc_req *, krb5_principal *); + +static krb5_error_code +db_get_svc_princ(krb5_context, krb5_principal, krb5_flags, + krb5_db_entry **, const char **); + +static krb5_error_code +search_sprinc(kdc_realm_t *, krb5_kdc_req *, krb5_flags, + krb5_db_entry **, const char **); + +/*ARGSUSED*/ +krb5_error_code +process_tgs_req(struct server_handle *handle, krb5_data *pkt, + const krb5_fulladdr *from, krb5_data **response) +{ + krb5_keyblock * subkey = 0; + krb5_keyblock *header_key = NULL; + krb5_kdc_req *request = 0; + krb5_db_entry *server = NULL; + krb5_db_entry *stkt_server = NULL; + krb5_kdc_rep reply; + krb5_enc_kdc_rep_part reply_encpart; + krb5_ticket ticket_reply, *header_ticket = 0; + int st_idx = 0; + krb5_enc_tkt_part enc_tkt_reply; + int newtransited = 0; + krb5_error_code retval = 0; + krb5_keyblock encrypting_key; + krb5_timestamp kdc_time, authtime = 0; + krb5_keyblock session_key; + krb5_keyblock *reply_key = NULL; + krb5_key_data *server_key; + krb5_principal cprinc = NULL, sprinc = NULL, altcprinc = NULL; + krb5_last_req_entry *nolrarray[2], nolrentry; + int errcode; + const char *status = 0; + krb5_enc_tkt_part *header_enc_tkt = NULL; /* TGT */ + krb5_enc_tkt_part *subject_tkt = NULL; /* TGT or evidence ticket */ + krb5_db_entry *client = NULL, *header_server = NULL; + krb5_db_entry *local_tgt, *local_tgt_storage = NULL; + krb5_pa_s4u_x509_user *s4u_x509_user = NULL; /* protocol transition request */ + krb5_authdata **kdc_issued_auth_data = NULL; /* auth data issued by KDC */ + unsigned int c_flags = 0, s_flags = 0; /* client/server KDB flags */ + krb5_boolean is_referral; + const char *emsg = NULL; + krb5_kvno ticket_kvno = 0; + struct kdc_request_state *state = NULL; + krb5_pa_data *pa_tgs_req; /*points into request*/ + krb5_data scratch; + krb5_pa_data **e_data = NULL; + kdc_realm_t *kdc_active_realm = NULL; + krb5_audit_state *au_state = NULL; + krb5_data **auth_indicators = NULL; + + memset(&reply, 0, sizeof(reply)); + memset(&reply_encpart, 0, sizeof(reply_encpart)); + memset(&ticket_reply, 0, sizeof(ticket_reply)); + memset(&enc_tkt_reply, 0, sizeof(enc_tkt_reply)); + session_key.contents = NULL; + + retval = decode_krb5_tgs_req(pkt, &request); + if (retval) + return retval; + /* Save pointer to client-requested service principal, in case of + * errors before a successful call to search_sprinc(). */ + sprinc = request->server; + + if (request->msg_type != KRB5_TGS_REQ) { + krb5_free_kdc_req(handle->kdc_err_context, request); + return KRB5_BADMSGTYPE; + } + + /* + * setup_server_realm() sets up the global realm-specific data pointer. + */ + kdc_active_realm = setup_server_realm(handle, request->server); + if (kdc_active_realm == NULL) { + krb5_free_kdc_req(handle->kdc_err_context, request); + return KRB5KDC_ERR_WRONG_REALM; + } + errcode = kdc_make_rstate(kdc_active_realm, &state); + if (errcode !=0) { + krb5_free_kdc_req(handle->kdc_err_context, request); + return errcode; + } + + /* Initialize audit state. */ + errcode = kau_init_kdc_req(kdc_context, request, from, &au_state); + if (errcode) { + krb5_free_kdc_req(handle->kdc_err_context, request); + return errcode; + } + /* Seed the audit trail with the request ID and basic information. */ + kau_tgs_req(kdc_context, TRUE, au_state); + + errcode = kdc_process_tgs_req(kdc_active_realm, + request, from, pkt, &header_ticket, + &header_server, &header_key, &subkey, + &pa_tgs_req); + if (header_ticket && header_ticket->enc_part2) + cprinc = header_ticket->enc_part2->client; + + if (errcode) { + status = "PROCESS_TGS"; + goto cleanup; + } + + if (!header_ticket) { + errcode = KRB5_NO_TKT_SUPPLIED; /* XXX? */ + status="UNEXPECTED NULL in header_ticket"; + goto cleanup; + } + errcode = kau_make_tkt_id(kdc_context, header_ticket, + &au_state->tkt_in_id); + if (errcode) { + status = "GENERATE_TICKET_ID"; + goto cleanup; + } + + scratch.length = pa_tgs_req->length; + scratch.data = (char *) pa_tgs_req->contents; + errcode = kdc_find_fast(&request, &scratch, subkey, + header_ticket->enc_part2->session, state, NULL); + /* Reset sprinc because kdc_find_fast() can replace request. */ + sprinc = request->server; + if (errcode !=0) { + status = "FIND_FAST"; + goto cleanup; + } + + errcode = get_local_tgt(kdc_context, &sprinc->realm, header_server, + &local_tgt, &local_tgt_storage); + if (errcode) { + status = "GET_LOCAL_TGT"; + goto cleanup; + } + + /* Ignore (for now) the request modification due to FAST processing. */ + au_state->request = request; + + /* + * Pointer to the encrypted part of the header ticket, which may be + * replaced to point to the encrypted part of the evidence ticket + * if constrained delegation is used. This simplifies the number of + * special cases for constrained delegation. + */ + header_enc_tkt = header_ticket->enc_part2; + + /* + * We've already dealt with the AP_REQ authentication, so we can + * use header_ticket freely. The encrypted part (if any) has been + * decrypted with the session key. + */ + + au_state->stage = SRVC_PRINC; + + /* XXX make sure server here has the proper realm...taken from AP_REQ + header? */ + + setflag(s_flags, KRB5_KDB_FLAG_ALIAS_OK); + if (isflagset(request->kdc_options, KDC_OPT_CANONICALIZE)) { + setflag(c_flags, KRB5_KDB_FLAG_CANONICALIZE); + setflag(s_flags, KRB5_KDB_FLAG_CANONICALIZE); + } + + errcode = search_sprinc(kdc_active_realm, request, s_flags, &server, + &status); + if (errcode != 0) + goto cleanup; + sprinc = server->princ; + + /* If we got a cross-realm TGS which is not the requested server, we are + * issuing a referral (or alternate TGT, which we treat similarly). */ + is_referral = is_cross_tgs_principal(server->princ) && + !krb5_principal_compare(kdc_context, request->server, server->princ); + + au_state->stage = VALIDATE_POL; + + if ((errcode = krb5_timeofday(kdc_context, &kdc_time))) { + status = "TIME_OF_DAY"; + goto cleanup; + } + + if ((retval = validate_tgs_request(kdc_active_realm, + request, *server, header_ticket, + kdc_time, &status, &e_data))) { + if (!status) + status = "UNKNOWN_REASON"; + if (retval == KDC_ERR_POLICY || retval == KDC_ERR_BADOPTION) + au_state->violation = PROT_CONSTRAINT; + errcode = retval + ERROR_TABLE_BASE_krb5; + goto cleanup; + } + + if (!is_local_principal(kdc_active_realm, header_enc_tkt->client)) + setflag(c_flags, KRB5_KDB_FLAG_CROSS_REALM); + + /* Check for protocol transition */ + errcode = kdc_process_s4u2self_req(kdc_active_realm, + request, + header_enc_tkt->client, + server, + subkey, + header_enc_tkt->session, + kdc_time, + &s4u_x509_user, + &client, + &status); + if (s4u_x509_user != NULL || errcode != 0) { + if (s4u_x509_user != NULL) + au_state->s4u2self_user = s4u_x509_user->user_id.user; + if (errcode == KDC_ERR_POLICY || errcode == KDC_ERR_BADOPTION) + au_state->violation = PROT_CONSTRAINT; + au_state->status = status; + kau_s4u2self(kdc_context, errcode ? FALSE : TRUE, au_state); + au_state->s4u2self_user = NULL; + } + + if (errcode) + goto cleanup; + if (s4u_x509_user != NULL) { + setflag(c_flags, KRB5_KDB_FLAG_PROTOCOL_TRANSITION); + if (is_referral) { + /* The requesting server appears to no longer exist, and we found + * a referral instead. Treat this as a server lookup failure. */ + errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; + status = "LOOKING_UP_SERVER"; + goto cleanup; + } + } + + /* Deal with user-to-user and constrained delegation */ + errcode = decrypt_2ndtkt(kdc_active_realm, request, c_flags, + &stkt_server, &status); + if (errcode) + goto cleanup; + + if (isflagset(request->kdc_options, KDC_OPT_CNAME_IN_ADDL_TKT)) { + /* Do constrained delegation protocol and authorization checks */ + errcode = kdc_process_s4u2proxy_req(kdc_active_realm, + request, + request->second_ticket[st_idx]->enc_part2, + stkt_server, + header_ticket->enc_part2->client, + request->server, + &status); + if (errcode == KDC_ERR_POLICY || errcode == KDC_ERR_BADOPTION) + au_state->violation = PROT_CONSTRAINT; + else if (errcode) + au_state->violation = LOCAL_POLICY; + au_state->status = status; + retval = kau_make_tkt_id(kdc_context, request->second_ticket[st_idx], + &au_state->evid_tkt_id); + if (retval) { + status = "GENERATE_TICKET_ID"; + errcode = retval; + goto cleanup; + } + kau_s4u2proxy(kdc_context, errcode ? FALSE : TRUE, au_state); + if (errcode) + goto cleanup; + + setflag(c_flags, KRB5_KDB_FLAG_CONSTRAINED_DELEGATION); + + assert(krb5_is_tgs_principal(header_ticket->server)); + + assert(client == NULL); /* assured by kdc_process_s4u2self_req() */ + client = stkt_server; + stkt_server = NULL; + } else if (request->kdc_options & KDC_OPT_ENC_TKT_IN_SKEY) { + krb5_db_free_principal(kdc_context, stkt_server); + stkt_server = NULL; + } else + assert(stkt_server == NULL); + + au_state->stage = ISSUE_TKT; + + errcode = gen_session_key(kdc_active_realm, request, server, &session_key, + &status); + if (errcode) + goto cleanup; + + /* + * subject_tkt will refer to the evidence ticket (for constrained + * delegation) or the TGT. The distinction from header_enc_tkt is + * necessary because the TGS signature only protects some fields: + * the others could be forged by a malicious server. + */ + + if (isflagset(c_flags, KRB5_KDB_FLAG_CONSTRAINED_DELEGATION)) + subject_tkt = request->second_ticket[st_idx]->enc_part2; + else + subject_tkt = header_enc_tkt; + authtime = subject_tkt->times.authtime; + + /* Extract auth indicators from the subject ticket, except for S4U2Proxy + * requests (where the client didn't authenticate). */ + if (s4u_x509_user == NULL) { + errcode = get_auth_indicators(kdc_context, subject_tkt, local_tgt, + &auth_indicators); + if (errcode) { + status = "GET_AUTH_INDICATORS"; + goto cleanup; + } + } + + errcode = check_indicators(kdc_context, server, auth_indicators); + if (errcode) { + status = "HIGHER_AUTHENTICATION_REQUIRED"; + goto cleanup; + } + + if (is_referral) + ticket_reply.server = server->princ; + else + ticket_reply.server = request->server; /* XXX careful for realm... */ + + enc_tkt_reply.flags = OPTS2FLAGS(request->kdc_options); + enc_tkt_reply.flags |= COPY_TKT_FLAGS(header_enc_tkt->flags); + enc_tkt_reply.times.starttime = 0; + + if (isflagset(server->attributes, KRB5_KDB_OK_AS_DELEGATE)) + setflag(enc_tkt_reply.flags, TKT_FLG_OK_AS_DELEGATE); + + /* Indicate support for encrypted padata (RFC 6806). */ + setflag(enc_tkt_reply.flags, TKT_FLG_ENC_PA_REP); + + /* don't use new addresses unless forwarded, see below */ + + enc_tkt_reply.caddrs = header_enc_tkt->caddrs; + /* noaddrarray[0] = 0; */ + reply_encpart.caddrs = 0;/* optional...don't put it in */ + reply_encpart.enc_padata = NULL; + + /* + * It should be noted that local policy may affect the + * processing of any of these flags. For example, some + * realms may refuse to issue renewable tickets + */ + + if (isflagset(request->kdc_options, KDC_OPT_FORWARDABLE)) { + + if (isflagset(c_flags, KRB5_KDB_FLAG_PROTOCOL_TRANSITION)) { + /* + * If S4U2Self principal is not forwardable, then mark ticket as + * unforwardable. This behaviour matches Windows, but it is + * different to the MIT AS-REQ path, which returns an error + * (KDC_ERR_POLICY) if forwardable tickets cannot be issued. + * + * Consider this block the S4U2Self equivalent to + * validate_forwardable(). + */ + if (client != NULL && + isflagset(client->attributes, KRB5_KDB_DISALLOW_FORWARDABLE)) + clear(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE); + /* + * Forwardable flag is propagated along referral path. + */ + else if (!isflagset(header_enc_tkt->flags, TKT_FLG_FORWARDABLE)) + clear(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE); + /* + * OK_TO_AUTH_AS_DELEGATE must be set on the service requesting + * S4U2Self in order for forwardable tickets to be returned. + */ + else if (!is_referral && + !isflagset(server->attributes, + KRB5_KDB_OK_TO_AUTH_AS_DELEGATE)) + clear(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE); + } + } + + if (isflagset(request->kdc_options, KDC_OPT_FORWARDED) || + isflagset(request->kdc_options, KDC_OPT_PROXY)) { + + /* include new addresses in ticket & reply */ + + enc_tkt_reply.caddrs = request->addresses; + reply_encpart.caddrs = request->addresses; + } + /* We don't currently handle issuing anonymous tickets based on + * non-anonymous ones, so just ignore the option. */ + if (isflagset(request->kdc_options, KDC_OPT_REQUEST_ANONYMOUS) && + !isflagset(header_enc_tkt->flags, TKT_FLG_ANONYMOUS)) + clear(enc_tkt_reply.flags, TKT_FLG_ANONYMOUS); + + if (isflagset(request->kdc_options, KDC_OPT_POSTDATED)) { + setflag(enc_tkt_reply.flags, TKT_FLG_INVALID); + enc_tkt_reply.times.starttime = request->from; + } else + enc_tkt_reply.times.starttime = kdc_time; + + if (isflagset(request->kdc_options, KDC_OPT_VALIDATE)) { + assert(isflagset(c_flags, KRB5_KDB_FLAGS_S4U) == 0); + /* BEWARE of allocation hanging off of ticket & enc_part2, it belongs + to the caller */ + ticket_reply = *(header_ticket); + enc_tkt_reply = *(header_ticket->enc_part2); + enc_tkt_reply.authorization_data = NULL; + clear(enc_tkt_reply.flags, TKT_FLG_INVALID); + } + + if (isflagset(request->kdc_options, KDC_OPT_RENEW)) { + krb5_timestamp old_starttime; + krb5_deltat old_life; + + assert(isflagset(c_flags, KRB5_KDB_FLAGS_S4U) == 0); + /* BEWARE of allocation hanging off of ticket & enc_part2, it belongs + to the caller */ + ticket_reply = *(header_ticket); + enc_tkt_reply = *(header_ticket->enc_part2); + enc_tkt_reply.authorization_data = NULL; + + old_starttime = enc_tkt_reply.times.starttime ? + enc_tkt_reply.times.starttime : enc_tkt_reply.times.authtime; + old_life = enc_tkt_reply.times.endtime - old_starttime; + + enc_tkt_reply.times.starttime = kdc_time; + enc_tkt_reply.times.endtime = + min(header_ticket->enc_part2->times.renew_till, + kdc_time + old_life); + } else { + /* not a renew request */ + enc_tkt_reply.times.starttime = kdc_time; + + kdc_get_ticket_endtime(kdc_active_realm, enc_tkt_reply.times.starttime, + header_enc_tkt->times.endtime, request->till, + client, server, &enc_tkt_reply.times.endtime); + } + + kdc_get_ticket_renewtime(kdc_active_realm, request, header_enc_tkt, client, + server, &enc_tkt_reply); + + /* + * Set authtime to be the same as header or evidence ticket's + */ + enc_tkt_reply.times.authtime = authtime; + + /* starttime is optional, and treated as authtime if not present. + so we can nuke it if it matches */ + if (enc_tkt_reply.times.starttime == enc_tkt_reply.times.authtime) + enc_tkt_reply.times.starttime = 0; + + if (isflagset(c_flags, KRB5_KDB_FLAG_PROTOCOL_TRANSITION)) { + altcprinc = s4u_x509_user->user_id.user; + } else if (isflagset(c_flags, KRB5_KDB_FLAG_CONSTRAINED_DELEGATION)) { + altcprinc = subject_tkt->client; + } else { + altcprinc = NULL; + } + if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) { + krb5_enc_tkt_part *t2enc = request->second_ticket[st_idx]->enc_part2; + encrypting_key = *(t2enc->session); + } else { + /* + * Find the server key + */ + if ((errcode = krb5_dbe_find_enctype(kdc_context, server, + -1, /* ignore keytype */ + -1, /* Ignore salttype */ + 0, /* Get highest kvno */ + &server_key))) { + status = "FINDING_SERVER_KEY"; + goto cleanup; + } + + /* + * Convert server.key into a real key + * (it may be encrypted in the database) + */ + if ((errcode = krb5_dbe_decrypt_key_data(kdc_context, NULL, + server_key, &encrypting_key, + NULL))) { + status = "DECRYPT_SERVER_KEY"; + goto cleanup; + } + } + + if (isflagset(c_flags, KRB5_KDB_FLAG_CONSTRAINED_DELEGATION)) { + /* + * Don't allow authorization data to be disabled if constrained + * delegation is requested. We don't want to deny the server + * the ability to validate that delegation was used. + */ + clear(server->attributes, KRB5_KDB_NO_AUTH_DATA_REQUIRED); + } + if (isflagset(server->attributes, KRB5_KDB_NO_AUTH_DATA_REQUIRED) == 0) { + /* + * If we are not doing protocol transition/constrained delegation + * try to lookup the client principal so plugins can add additional + * authorization information. + * + * Always validate authorization data for constrained delegation + * because we must validate the KDC signatures. + */ + if (!isflagset(c_flags, KRB5_KDB_FLAGS_S4U)) { + /* Generate authorization data so we can include it in ticket */ + setflag(c_flags, KRB5_KDB_FLAG_INCLUDE_PAC); + /* Map principals from foreign (possibly non-AD) realms */ + setflag(c_flags, KRB5_KDB_FLAG_MAP_PRINCIPALS); + + assert(client == NULL); /* should not have been set already */ + + errcode = krb5_db_get_principal(kdc_context, subject_tkt->client, + c_flags, &client); + } + } + + if (isflagset(c_flags, KRB5_KDB_FLAG_PROTOCOL_TRANSITION) && + !isflagset(c_flags, KRB5_KDB_FLAG_CROSS_REALM)) + enc_tkt_reply.client = s4u_x509_user->user_id.user; + else + enc_tkt_reply.client = subject_tkt->client; + + enc_tkt_reply.session = &session_key; + enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS; + enc_tkt_reply.transited.tr_contents = empty_string; /* equivalent of "" */ + + /* + * Only add the realm of the presented tgt to the transited list if + * it is different than the local realm (cross-realm) and it is different + * than the realm of the client (since the realm of the client is already + * implicitly part of the transited list and should not be explicitly + * listed). + */ + /* realm compare is like strcmp, but knows how to deal with these args */ + if (krb5_realm_compare(kdc_context, header_ticket->server, tgs_server) || + krb5_realm_compare(kdc_context, header_ticket->server, + enc_tkt_reply.client)) { + /* tgt issued by local realm or issued by realm of client */ + enc_tkt_reply.transited = header_enc_tkt->transited; + } else { + /* tgt issued by some other realm and not the realm of the client */ + /* assemble new transited field into allocated storage */ + if (header_enc_tkt->transited.tr_type != + KRB5_DOMAIN_X500_COMPRESS) { + status = "VALIDATE_TRANSIT_TYPE"; + errcode = KRB5KDC_ERR_TRTYPE_NOSUPP; + goto cleanup; + } + memset(&enc_tkt_reply.transited, 0, sizeof(enc_tkt_reply.transited)); + enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS; + if ((errcode = + add_to_transited(&header_enc_tkt->transited.tr_contents, + &enc_tkt_reply.transited.tr_contents, + header_ticket->server, + enc_tkt_reply.client, + request->server))) { + status = "ADD_TO_TRANSITED_LIST"; + goto cleanup; + } + newtransited = 1; + } + if (isflagset(c_flags, KRB5_KDB_FLAG_CROSS_REALM)) { + errcode = validate_transit_path(kdc_context, header_enc_tkt->client, + server, header_server); + if (errcode) { + status = "NON_TRANSITIVE"; + goto cleanup; + } + } + if (!isflagset (request->kdc_options, KDC_OPT_DISABLE_TRANSITED_CHECK)) { + errcode = kdc_check_transited_list (kdc_active_realm, + &enc_tkt_reply.transited.tr_contents, + krb5_princ_realm (kdc_context, header_enc_tkt->client), + krb5_princ_realm (kdc_context, request->server)); + if (errcode == 0) { + setflag (enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED); + } else { + log_tgs_badtrans(kdc_context, cprinc, sprinc, + &enc_tkt_reply.transited.tr_contents, errcode); + } + } else + krb5_klog_syslog(LOG_INFO, _("not checking transit path")); + if (kdc_active_realm->realm_reject_bad_transit && + !isflagset(enc_tkt_reply.flags, TKT_FLG_TRANSIT_POLICY_CHECKED)) { + errcode = KRB5KDC_ERR_POLICY; + status = "BAD_TRANSIT"; + au_state->violation = LOCAL_POLICY; + goto cleanup; + } + + errcode = handle_authdata(kdc_context, c_flags, client, server, + header_server, local_tgt, + subkey != NULL ? subkey : + header_ticket->enc_part2->session, + &encrypting_key, /* U2U or server key */ + header_key, + pkt, + request, + s4u_x509_user ? + s4u_x509_user->user_id.user : NULL, + subject_tkt, + auth_indicators, + &enc_tkt_reply); + if (errcode) { + krb5_klog_syslog(LOG_INFO, _("TGS_REQ : handle_authdata (%d)"), + errcode); + status = "HANDLE_AUTHDATA"; + goto cleanup; + } + + ticket_reply.enc_part2 = &enc_tkt_reply; + + /* + * If we are doing user-to-user authentication, then make sure + * that the client for the second ticket matches the request + * server, and then encrypt the ticket using the session key of + * the second ticket. + */ + if (isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) { + /* + * Make sure the client for the second ticket matches + * requested server. + */ + krb5_enc_tkt_part *t2enc = request->second_ticket[st_idx]->enc_part2; + krb5_principal client2 = t2enc->client; + if (!krb5_principal_compare(kdc_context, request->server, client2)) { + altcprinc = client2; + errcode = KRB5KDC_ERR_SERVER_NOMATCH; + status = "2ND_TKT_MISMATCH"; + au_state->status = status; + kau_u2u(kdc_context, FALSE, au_state); + goto cleanup; + } + + ticket_kvno = 0; + ticket_reply.enc_part.enctype = t2enc->session->enctype; + kau_u2u(kdc_context, TRUE, au_state); + st_idx++; + } else { + ticket_kvno = server_key->key_data_kvno; + } + + errcode = krb5_encrypt_tkt_part(kdc_context, &encrypting_key, + &ticket_reply); + if (!isflagset(request->kdc_options, KDC_OPT_ENC_TKT_IN_SKEY)) + krb5_free_keyblock_contents(kdc_context, &encrypting_key); + if (errcode) { + status = "ENCRYPT_TICKET"; + goto cleanup; + } + ticket_reply.enc_part.kvno = ticket_kvno; + /* Start assembling the response */ + au_state->stage = ENCR_REP; + reply.msg_type = KRB5_TGS_REP; + if (isflagset(c_flags, KRB5_KDB_FLAG_PROTOCOL_TRANSITION) && + krb5int_find_pa_data(kdc_context, request->padata, + KRB5_PADATA_S4U_X509_USER) != NULL) { + errcode = kdc_make_s4u2self_rep(kdc_context, + subkey, + header_ticket->enc_part2->session, + s4u_x509_user, + &reply, + &reply_encpart); + if (errcode) { + status = "MAKE_S4U2SELF_PADATA"; + au_state->status = status; + } + kau_s4u2self(kdc_context, errcode ? FALSE : TRUE, au_state); + if (errcode) + goto cleanup; + } + + reply.client = enc_tkt_reply.client; + reply.enc_part.kvno = 0;/* We are using the session key */ + reply.ticket = &ticket_reply; + + reply_encpart.session = &session_key; + reply_encpart.nonce = request->nonce; + + /* copy the time fields */ + reply_encpart.times = enc_tkt_reply.times; + + nolrentry.lr_type = KRB5_LRQ_NONE; + nolrentry.value = 0; + nolrentry.magic = 0; + nolrarray[0] = &nolrentry; + nolrarray[1] = 0; + reply_encpart.last_req = nolrarray; /* not available for TGS reqs */ + reply_encpart.key_exp = 0;/* ditto */ + reply_encpart.flags = enc_tkt_reply.flags; + reply_encpart.server = ticket_reply.server; + + /* use the session key in the ticket, unless there's a subsession key + in the AP_REQ */ + reply.enc_part.enctype = subkey ? subkey->enctype : + header_ticket->enc_part2->session->enctype; + errcode = kdc_fast_response_handle_padata(state, request, &reply, + subkey ? subkey->enctype : header_ticket->enc_part2->session->enctype); + if (errcode !=0 ) { + status = "MAKE_FAST_RESPONSE"; + goto cleanup; + } + errcode =kdc_fast_handle_reply_key(state, + subkey?subkey:header_ticket->enc_part2->session, &reply_key); + if (errcode) { + status = "MAKE_FAST_REPLY_KEY"; + goto cleanup; + } + errcode = return_enc_padata(kdc_context, pkt, request, + reply_key, server, &reply_encpart, + is_referral && + isflagset(s_flags, + KRB5_KDB_FLAG_CANONICALIZE)); + if (errcode) { + status = "KDC_RETURN_ENC_PADATA"; + goto cleanup; + } + + errcode = kau_make_tkt_id(kdc_context, &ticket_reply, &au_state->tkt_out_id); + if (errcode) { + status = "GENERATE_TICKET_ID"; + goto cleanup; + } + + if (kdc_fast_hide_client(state)) + reply.client = (krb5_principal)krb5_anonymous_principal(); + errcode = krb5_encode_kdc_rep(kdc_context, KRB5_TGS_REP, &reply_encpart, + subkey ? 1 : 0, + reply_key, + &reply, response); + if (errcode) { + status = "ENCODE_KDC_REP"; + } else { + status = "ISSUE"; + } + + memset(ticket_reply.enc_part.ciphertext.data, 0, + ticket_reply.enc_part.ciphertext.length); + free(ticket_reply.enc_part.ciphertext.data); + /* these parts are left on as a courtesy from krb5_encode_kdc_rep so we + can use them in raw form if needed. But, we don't... */ + memset(reply.enc_part.ciphertext.data, 0, + reply.enc_part.ciphertext.length); + free(reply.enc_part.ciphertext.data); + +cleanup: + assert(status != NULL); + if (reply_key) + krb5_free_keyblock(kdc_context, reply_key); + if (errcode) + emsg = krb5_get_error_message (kdc_context, errcode); + + au_state->status = status; + if (!errcode) + au_state->reply = &reply; + kau_tgs_req(kdc_context, errcode ? FALSE : TRUE, au_state); + kau_free_kdc_req(au_state); + + log_tgs_req(kdc_context, from, request, &reply, cprinc, + sprinc, altcprinc, authtime, + c_flags, status, errcode, emsg); + if (errcode) { + krb5_free_error_message (kdc_context, emsg); + emsg = NULL; + } + + if (errcode) { + int got_err = 0; + if (status == 0) { + status = krb5_get_error_message (kdc_context, errcode); + got_err = 1; + } + errcode -= ERROR_TABLE_BASE_krb5; + if (errcode < 0 || errcode > KRB_ERR_MAX) + errcode = KRB_ERR_GENERIC; + + retval = prepare_error_tgs(state, request, header_ticket, errcode, + (server != NULL) ? server->princ : NULL, + response, status, e_data); + if (got_err) { + krb5_free_error_message (kdc_context, status); + status = 0; + } + } + + if (header_ticket != NULL) + krb5_free_ticket(kdc_context, header_ticket); + if (request != NULL) + krb5_free_kdc_req(kdc_context, request); + if (state) + kdc_free_rstate(state); + krb5_db_free_principal(kdc_context, server); + krb5_db_free_principal(kdc_context, stkt_server); + krb5_db_free_principal(kdc_context, header_server); + krb5_db_free_principal(kdc_context, client); + krb5_db_free_principal(kdc_context, local_tgt_storage); + if (session_key.contents != NULL) + krb5_free_keyblock_contents(kdc_context, &session_key); + if (newtransited) + free(enc_tkt_reply.transited.tr_contents.data); + if (s4u_x509_user != NULL) + krb5_free_pa_s4u_x509_user(kdc_context, s4u_x509_user); + if (kdc_issued_auth_data != NULL) + krb5_free_authdata(kdc_context, kdc_issued_auth_data); + if (subkey != NULL) + krb5_free_keyblock(kdc_context, subkey); + if (header_key != NULL) + krb5_free_keyblock(kdc_context, header_key); + if (reply.padata) + krb5_free_pa_data(kdc_context, reply.padata); + if (reply_encpart.enc_padata) + krb5_free_pa_data(kdc_context, reply_encpart.enc_padata); + if (enc_tkt_reply.authorization_data != NULL) + krb5_free_authdata(kdc_context, enc_tkt_reply.authorization_data); + krb5_free_pa_data(kdc_context, e_data); + k5_free_data_ptr_list(auth_indicators); + + return retval; +} + +static krb5_error_code +prepare_error_tgs (struct kdc_request_state *state, + krb5_kdc_req *request, krb5_ticket *ticket, int error, + krb5_principal canon_server, + krb5_data **response, const char *status, + krb5_pa_data **e_data) +{ + krb5_error errpkt; + krb5_error_code retval = 0; + krb5_data *scratch, *e_data_asn1 = NULL, *fast_edata = NULL; + kdc_realm_t *kdc_active_realm = state->realm_data; + + errpkt.ctime = request->nonce; + errpkt.cusec = 0; + + if ((retval = krb5_us_timeofday(kdc_context, &errpkt.stime, + &errpkt.susec))) + return(retval); + errpkt.error = error; + errpkt.server = request->server; + if (ticket && ticket->enc_part2) + errpkt.client = ticket->enc_part2->client; + else + errpkt.client = NULL; + errpkt.text.length = strlen(status); + if (!(errpkt.text.data = strdup(status))) + return ENOMEM; + + if (!(scratch = (krb5_data *)malloc(sizeof(*scratch)))) { + free(errpkt.text.data); + return ENOMEM; + } + + if (e_data != NULL) { + retval = encode_krb5_padata_sequence(e_data, &e_data_asn1); + if (retval) { + free(scratch); + free(errpkt.text.data); + return retval; + } + errpkt.e_data = *e_data_asn1; + } else + errpkt.e_data = empty_data(); + + retval = kdc_fast_handle_error(kdc_context, state, request, e_data, + &errpkt, &fast_edata); + if (retval) { + free(scratch); + free(errpkt.text.data); + krb5_free_data(kdc_context, e_data_asn1); + return retval; + } + if (fast_edata) + errpkt.e_data = *fast_edata; + if (kdc_fast_hide_client(state) && errpkt.client != NULL) + errpkt.client = (krb5_principal)krb5_anonymous_principal(); + retval = krb5_mk_error(kdc_context, &errpkt, scratch); + free(errpkt.text.data); + krb5_free_data(kdc_context, e_data_asn1); + krb5_free_data(kdc_context, fast_edata); + if (retval) + free(scratch); + else + *response = scratch; + + return retval; +} + +/* KDC options that require a second ticket */ +#define STKT_OPTIONS (KDC_OPT_CNAME_IN_ADDL_TKT | KDC_OPT_ENC_TKT_IN_SKEY) +/* + * Get the key for the second ticket, if any, and decrypt it. + */ +static krb5_error_code +decrypt_2ndtkt(kdc_realm_t *kdc_active_realm, krb5_kdc_req *req, + krb5_flags flags, krb5_db_entry **server_out, + const char **status) +{ + krb5_error_code retval; + krb5_db_entry *server = NULL; + krb5_keyblock *key; + krb5_kvno kvno; + krb5_ticket *stkt; + + if (!(req->kdc_options & STKT_OPTIONS)) + return 0; + + stkt = req->second_ticket[0]; + retval = kdc_get_server_key(kdc_context, stkt, + flags, + TRUE, /* match_enctype */ + &server, + &key, + &kvno); + if (retval != 0) { + *status = "2ND_TKT_SERVER"; + goto cleanup; + } + retval = krb5_decrypt_tkt_part(kdc_context, key, + req->second_ticket[0]); + krb5_free_keyblock(kdc_context, key); + if (retval != 0) { + *status = "2ND_TKT_DECRYPT"; + goto cleanup; + } + *server_out = server; + server = NULL; +cleanup: + krb5_db_free_principal(kdc_context, server); + return retval; +} + +static krb5_error_code +get_2ndtkt_enctype(kdc_realm_t *kdc_active_realm, krb5_kdc_req *req, + krb5_enctype *useenctype, const char **status) +{ + krb5_enctype etype; + krb5_ticket *stkt = req->second_ticket[0]; + int i; + + etype = stkt->enc_part2->session->enctype; + if (!krb5_c_valid_enctype(etype)) { + *status = "BAD_ETYPE_IN_2ND_TKT"; + return KRB5KDC_ERR_ETYPE_NOSUPP; + } + for (i = 0; i < req->nktypes; i++) { + if (req->ktype[i] == etype) { + *useenctype = etype; + break; + } + } + return 0; +} + +static krb5_error_code +gen_session_key(kdc_realm_t *kdc_active_realm, krb5_kdc_req *req, + krb5_db_entry *server, krb5_keyblock *skey, + const char **status) +{ + krb5_error_code retval; + krb5_enctype useenctype = 0; + + /* + * Some special care needs to be taken in the user-to-user + * case, since we don't know what keytypes the application server + * which is doing user-to-user authentication can support. We + * know that it at least must be able to support the encryption + * type of the session key in the TGT, since otherwise it won't be + * able to decrypt the U2U ticket! So we use that in preference + * to anything else. + */ + if (req->kdc_options & KDC_OPT_ENC_TKT_IN_SKEY) { + retval = get_2ndtkt_enctype(kdc_active_realm, req, &useenctype, + status); + if (retval != 0) + goto cleanup; + } + if (useenctype == 0) { + useenctype = select_session_keytype(kdc_active_realm, server, + req->nktypes, + req->ktype); + } + if (useenctype == 0) { + /* unsupported ktype */ + *status = "BAD_ENCRYPTION_TYPE"; + retval = KRB5KDC_ERR_ETYPE_NOSUPP; + goto cleanup; + } + retval = krb5_c_make_random_key(kdc_context, useenctype, skey); + if (retval != 0) { + /* random key failed */ + *status = "MAKE_RANDOM_KEY"; + goto cleanup; + } +cleanup: + return retval; +} + +/* + * The request seems to be for a ticket-granting service somewhere else, + * but we don't have a ticket for the final TGS. Try to give the requestor + * some intermediate realm. + */ +static krb5_error_code +find_alternate_tgs(kdc_realm_t *kdc_active_realm, krb5_principal princ, + krb5_db_entry **server_ptr, const char **status) +{ + krb5_error_code retval; + krb5_principal *plist = NULL, *pl2; + krb5_data tmp; + krb5_db_entry *server = NULL; + + *server_ptr = NULL; + assert(is_cross_tgs_principal(princ)); + if ((retval = krb5_walk_realm_tree(kdc_context, + krb5_princ_realm(kdc_context, princ), + krb5_princ_component(kdc_context, princ, 1), + &plist, KRB5_REALM_BRANCH_CHAR))) { + goto cleanup; + } + /* move to the end */ + for (pl2 = plist; *pl2; pl2++); + + /* the first entry in this array is for krbtgt/local@local, so we + ignore it */ + while (--pl2 > plist) { + tmp = *krb5_princ_realm(kdc_context, *pl2); + krb5_princ_set_realm(kdc_context, *pl2, + krb5_princ_realm(kdc_context, princ)); + retval = db_get_svc_princ(kdc_context, *pl2, 0, &server, status); + krb5_princ_set_realm(kdc_context, *pl2, &tmp); + if (retval == KRB5_KDB_NOENTRY) + continue; + else if (retval) + goto cleanup; + + log_tgs_alt_tgt(kdc_context, server->princ); + *server_ptr = server; + server = NULL; + goto cleanup; + } +cleanup: + if (retval == 0 && *server_ptr == NULL) + retval = KRB5_KDB_NOENTRY; + if (retval != 0) + *status = "UNKNOWN_SERVER"; + + krb5_free_realm_tree(kdc_context, plist); + krb5_db_free_principal(kdc_context, server); + return retval; +} + +/* Return true if item is an element of the space/comma-separated list. */ +static krb5_boolean +in_list(const char *list, const char *item) +{ + const char *p; + int len = strlen(item); + + if (list == NULL) + return FALSE; + for (p = strstr(list, item); p != NULL; p = strstr(p + 1, item)) { + if ((p == list || isspace((unsigned char)p[-1]) || p[-1] == ',') && + (p[len] == '\0' || isspace((unsigned char)p[len]) || + p[len] == ',')) + return TRUE; + } + return FALSE; +} + +/* + * Check whether the request satisfies the conditions for generating a referral + * TGT. The caller checks whether the hostname component looks like a FQDN. + */ +static krb5_boolean +is_referral_req(kdc_realm_t *kdc_active_realm, krb5_kdc_req *request) +{ + krb5_boolean ret = FALSE; + char *stype = NULL; + char *hostbased = kdc_active_realm->realm_hostbased; + char *no_referral = kdc_active_realm->realm_no_referral; + + if (!(request->kdc_options & KDC_OPT_CANONICALIZE)) + return FALSE; + + if (request->kdc_options & KDC_OPT_ENC_TKT_IN_SKEY) + return FALSE; + + if (krb5_princ_size(kdc_context, request->server) != 2) + return FALSE; + + stype = data2string(krb5_princ_component(kdc_context, request->server, 0)); + if (stype == NULL) + return FALSE; + switch (krb5_princ_type(kdc_context, request->server)) { + case KRB5_NT_UNKNOWN: + /* Allow referrals for NT-UNKNOWN principals, if configured. */ + if (!in_list(hostbased, stype) && !in_list(hostbased, "*")) + goto cleanup; + /* FALLTHROUGH */ + case KRB5_NT_SRV_HST: + case KRB5_NT_SRV_INST: + /* Deny referrals for specific service types, if configured. */ + if (in_list(no_referral, stype) || in_list(no_referral, "*")) + goto cleanup; + ret = TRUE; + break; + default: + goto cleanup; + } +cleanup: + free(stype); + return ret; +} + +/* + * Find a remote realm TGS principal for an unknown host-based service + * principal. + */ +static krb5_int32 +find_referral_tgs(kdc_realm_t *kdc_active_realm, krb5_kdc_req *request, + krb5_principal *krbtgt_princ) +{ + krb5_error_code retval = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; + char **realms = NULL, *hostname = NULL; + krb5_data srealm = request->server->realm; + + if (!is_referral_req(kdc_active_realm, request)) + goto cleanup; + + hostname = data2string(krb5_princ_component(kdc_context, + request->server, 1)); + if (hostname == NULL) { + retval = ENOMEM; + goto cleanup; + } + /* If the hostname doesn't contain a '.', it's not a FQDN. */ + if (strchr(hostname, '.') == NULL) + goto cleanup; + retval = krb5_get_host_realm(kdc_context, hostname, &realms); + if (retval) { + /* no match found */ + kdc_err(kdc_context, retval, "unable to find realm of host"); + goto cleanup; + } + /* Don't return a referral to the empty realm or the service realm. */ + if (realms == NULL || realms[0] == NULL || *realms[0] == '\0' || + data_eq_string(srealm, realms[0])) { + retval = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; + goto cleanup; + } + retval = krb5_build_principal(kdc_context, krbtgt_princ, + srealm.length, srealm.data, + "krbtgt", realms[0], (char *)0); +cleanup: + krb5_free_host_realm(kdc_context, realms); + free(hostname); + + return retval; +} + +static krb5_error_code +db_get_svc_princ(krb5_context ctx, krb5_principal princ, + krb5_flags flags, krb5_db_entry **server, + const char **status) +{ + krb5_error_code ret; + + ret = krb5_db_get_principal(ctx, princ, flags, server); + if (ret == KRB5_KDB_CANTLOCK_DB) + ret = KRB5KDC_ERR_SVC_UNAVAILABLE; + if (ret != 0) { + *status = "LOOKING_UP_SERVER"; + } + return ret; +} + +static krb5_error_code +search_sprinc(kdc_realm_t *kdc_active_realm, krb5_kdc_req *req, + krb5_flags flags, krb5_db_entry **server, const char **status) +{ + krb5_error_code ret; + krb5_principal princ = req->server; + krb5_principal reftgs = NULL; + krb5_boolean allow_referral; + + /* Do not allow referrals for u2u or ticket modification requests, because + * the server is supposed to match an already-issued ticket. */ + allow_referral = !(req->kdc_options & NO_REFERRAL_OPTION); + if (!allow_referral) + flags &= ~KRB5_KDB_FLAG_CANONICALIZE; + + ret = db_get_svc_princ(kdc_context, princ, flags, server, status); + if (ret == 0 || ret != KRB5_KDB_NOENTRY || !allow_referral) + goto cleanup; + + if (!is_cross_tgs_principal(req->server)) { + ret = find_referral_tgs(kdc_active_realm, req, &reftgs); + if (ret != 0) + goto cleanup; + ret = db_get_svc_princ(kdc_context, reftgs, flags, server, status); + if (ret == 0 || ret != KRB5_KDB_NOENTRY) + goto cleanup; + + princ = reftgs; + } + ret = find_alternate_tgs(kdc_active_realm, princ, server, status); + +cleanup: + if (ret != 0 && ret != KRB5KDC_ERR_SVC_UNAVAILABLE) { + ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN; + if (*status == NULL) + *status = "LOOKING_UP_SERVER"; + } + krb5_free_principal(kdc_context, reftgs); + return ret; +} |