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/*
* kdc/do_as_req.c
*
* Copyright 1990,1991 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. 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.
*
*
* KDC Routines to deal with AS_REQ's
*/
#include "k5-int.h"
#include "com_err.h"
#include <syslog.h>
#ifdef KRB5_USE_INET
#include <sys/types.h>
#include <netinet/in.h>
#ifndef hpux
#include <arpa/inet.h>
#endif /* hpux */
#endif /* KRB5_USE_INET */
#include "kdc_util.h"
#include "policy.h"
#include "adm.h"
#include "adm_proto.h"
#include "extern.h"
static krb5_error_code prepare_error_as PROTOTYPE((krb5_kdc_req *,
int,
krb5_data *,
krb5_data **));
/*ARGSUSED*/
krb5_error_code
process_as_req(request, from, portnum, response)
register krb5_kdc_req *request;
const krb5_fulladdr *from; /* who sent it ? */
int portnum;
krb5_data **response; /* filled in with a response packet */
{
krb5_db_entry client, server;
krb5_kdc_rep reply;
krb5_enc_kdc_rep_part reply_encpart;
krb5_ticket ticket_reply;
krb5_enc_tkt_part enc_tkt_reply;
krb5_error_code errcode;
int c_nprincs = 0, s_nprincs = 0;
krb5_boolean more;
krb5_timestamp kdc_time, authtime;
krb5_keyblock *session_key = 0;
krb5_keyblock encrypting_key;
const char *status;
krb5_encrypt_block eblock;
krb5_key_data *server_key, *client_key;
krb5_enctype useenctype;
#ifdef KRBCONF_KDC_MODIFIES_KDB
krb5_boolean update_client = 0;
#endif /* KRBCONF_KDC_MODIFIES_KDB */
krb5_data e_data;
register int i;
krb5_timestamp until, rtime;
char *cname = 0, *sname = 0, *fromstring = 0;
ticket_reply.enc_part.ciphertext.data = 0;
e_data.data = 0;
encrypting_key.contents = 0;
#ifdef KRB5_USE_INET
if (from->address->addrtype == ADDRTYPE_INET)
fromstring = (char *) inet_ntoa(*(struct in_addr *)from->address->contents);
#endif
if (!fromstring)
fromstring = "<unknown>";
if (!request->client) {
status = "NULL_CLIENT";
errcode = KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
goto errout;
}
if ((errcode = krb5_unparse_name(kdc_context, request->client, &cname))) {
status = "UNPARSING_CLIENT";
goto errout;
}
limit_string(cname);
if (!request->server) {
status = "NULL_SERVER";
errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
goto errout;
}
if ((errcode = krb5_unparse_name(kdc_context, request->server, &sname))) {
status = "UNPARSING_SERVER";
goto errout;
}
limit_string(sname);
c_nprincs = 1;
if ((errcode = krb5_db_get_principal(kdc_context, request->client,
&client, &c_nprincs, &more))) {
status = "LOOKING_UP_CLIENT";
c_nprincs = 0;
goto errout;
}
if (more) {
status = "NON-UNIQUE_CLIENT";
errcode = KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE;
goto errout;
} else if (c_nprincs != 1) {
status = "CLIENT_NOT_FOUND";
#ifdef KRBCONF_VAGUE_ERRORS
errcode = KRB5KRB_ERR_GENERIC;
#else
errcode = KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
#endif
goto errout;
}
s_nprincs = 1;
if ((errcode = krb5_db_get_principal(kdc_context, request->server, &server,
&s_nprincs, &more))) {
status = "LOOKING_UP_SERVER";
goto errout;
}
if (more) {
status = "NON-UNIQUE_SERVER";
errcode = KRB5KDC_ERR_PRINCIPAL_NOT_UNIQUE;
goto errout;
} else if (s_nprincs != 1) {
status = "SERVER_NOT_FOUND";
errcode = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
goto errout;
}
if ((errcode = krb5_timeofday(kdc_context, &kdc_time))) {
status = "TIMEOFDAY";
goto errout;
}
if ((errcode = validate_as_request(request, client, server,
kdc_time, &status))) {
if (!status)
status = "UNKNOWN_REASON";
errcode += ERROR_TABLE_BASE_krb5;
goto errout;
}
/*
* Select the keytype for the ticket session key.
*/
if ((useenctype = select_session_keytype(kdc_context, &server,
request->nktypes,
request->ktype)) == 0) {
/* unsupported ktype */
status = "BAD_ENCRYPTION_TYPE";
errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
goto errout;
}
krb5_use_enctype(kdc_context, &eblock, useenctype);
if ((errcode = krb5_random_key(kdc_context, &eblock,
krb5_enctype_array[useenctype]->random_sequence,
&session_key))) {
/* random key failed */
status = "RANDOM_KEY_FAILED";
goto errout;
}
ticket_reply.server = request->server;
enc_tkt_reply.flags = 0;
setflag(enc_tkt_reply.flags, TKT_FLG_INITIAL);
/* 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))
setflag(enc_tkt_reply.flags, TKT_FLG_FORWARDABLE);
if (isflagset(request->kdc_options, KDC_OPT_PROXIABLE))
setflag(enc_tkt_reply.flags, TKT_FLG_PROXIABLE);
if (isflagset(request->kdc_options, KDC_OPT_ALLOW_POSTDATE))
setflag(enc_tkt_reply.flags, TKT_FLG_MAY_POSTDATE);
enc_tkt_reply.session = session_key;
enc_tkt_reply.client = request->client;
enc_tkt_reply.transited.tr_type = KRB5_DOMAIN_X500_COMPRESS;
enc_tkt_reply.transited.tr_contents = empty_string; /* equivalent of "" */
enc_tkt_reply.times.authtime = kdc_time;
if (isflagset(request->kdc_options, KDC_OPT_POSTDATED)) {
setflag(enc_tkt_reply.flags, TKT_FLG_POSTDATED);
setflag(enc_tkt_reply.flags, TKT_FLG_INVALID);
enc_tkt_reply.times.starttime = request->from;
} else
enc_tkt_reply.times.starttime = kdc_time;
until = (request->till == 0) ? kdc_infinity : request->till;
enc_tkt_reply.times.endtime =
min(until,
min(enc_tkt_reply.times.starttime + client.max_life,
min(enc_tkt_reply.times.starttime + server.max_life,
enc_tkt_reply.times.starttime + max_life_for_realm)));
if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE_OK) &&
!isflagset(client.attributes, KRB5_KDB_DISALLOW_RENEWABLE) &&
(enc_tkt_reply.times.endtime < request->till)) {
/* we set the RENEWABLE option for later processing */
setflag(request->kdc_options, KDC_OPT_RENEWABLE);
request->rtime = request->till;
}
rtime = (request->rtime == 0) ? kdc_infinity : request->rtime;
if (isflagset(request->kdc_options, KDC_OPT_RENEWABLE)) {
/*
* XXX Should we squelch the output renew_till to be no
* earlier than the endtime of the ticket?
*/
setflag(enc_tkt_reply.flags, TKT_FLG_RENEWABLE);
enc_tkt_reply.times.renew_till =
min(rtime, enc_tkt_reply.times.starttime +
min(client.max_renewable_life,
min(server.max_renewable_life,
max_renewable_life_for_realm)));
} else
enc_tkt_reply.times.renew_till = 0; /* XXX */
/* 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;
enc_tkt_reply.caddrs = request->addresses;
enc_tkt_reply.authorization_data = 0;
/*
* Check the preauthentication if it is there.
*/
if (request->padata) {
errcode = check_padata(kdc_context, &client, request, &enc_tkt_reply);
if (errcode) {
#ifdef KRBCONF_KDC_MODIFIES_KDB
/*
* Note: this doesn't work if you're using slave servers!!!
* It also causes the database to be modified (and thus
* need to be locked) frequently.
*/
if (client.fail_auth_count < KRB5_MAX_FAIL_COUNT) {
client.fail_auth_count = client.fail_auth_count + 1;
if (client.fail_auth_count == KRB5_MAX_FAIL_COUNT) {
client.attributes |= KRB5_KDB_DISALLOW_ALL_TIX;
}
}
client.last_failed = kdc_time;
update_client = 1;
#endif
status = "PREAUTH_FAILED";
#ifdef KRBCONF_VAGUE_ERRORS
errcode = KRB5KRB_ERR_GENERIC;
#endif
goto errout;
}
}
/*
* Final check before handing out ticket: If the client requires
* preauthentication, verify that the proper kind of
* preauthentication was carried out.
*/
status = missing_required_preauth(&client, &server, &enc_tkt_reply);
if (status) {
errcode = KRB5KDC_ERR_PREAUTH_REQUIRED;
get_preauth_hint_list(request, &client, &server, &e_data);
goto errout;
}
ticket_reply.enc_part2 = &enc_tkt_reply;
/*
* 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 errout;
}
/* convert server.key into a real key (it may be encrypted
in the database) */
if ((errcode = krb5_dbekd_decrypt_key_data(kdc_context, &master_encblock,
server_key, &encrypting_key,
NULL))) {
status = "DECRYPT_SERVER_KEY";
goto errout;
}
if ((encrypting_key.enctype == ENCTYPE_DES_CBC_CRC) &&
(isflagset(server.attributes, KRB5_KDB_SUPPORT_DESMD5)))
encrypting_key.enctype = ENCTYPE_DES_CBC_MD5;
errcode = krb5_encrypt_tkt_part(kdc_context, &encrypting_key, &ticket_reply);
krb5_free_keyblock_contents(kdc_context, &encrypting_key);
encrypting_key.contents = 0;
if (errcode) {
status = "ENCRYPTING_TICKET";
goto errout;
}
ticket_reply.enc_part.kvno = server_key->key_data_kvno;
/*
* Find the appropriate client key. We search in the order specified
* by request keytype list.
*/
client_key = (krb5_key_data *) NULL;
for (i = 0; i < request->nktypes; i++) {
useenctype = request->ktype[i];
if (!valid_enctype(useenctype))
continue;
if (!krb5_dbe_find_enctype(kdc_context, &client, useenctype, -1,
0, &client_key))
break;
}
if (!(client_key)) {
/* Cannot find an appropriate key */
status = "CANT_FIND_CLIENT_KEY";
errcode = KRB5KDC_ERR_ETYPE_NOSUPP;
goto errout;
}
/* convert client.key_data into a real key */
if ((errcode = krb5_dbekd_decrypt_key_data(kdc_context, &master_encblock,
client_key, &encrypting_key,
NULL))) {
status = "DECRYPT_CLIENT_KEY";
goto errout;
}
encrypting_key.enctype = useenctype;
/* Start assembling the response */
reply.msg_type = KRB5_AS_REP;
reply.padata = 0;
reply.client = request->client;
reply.ticket = &ticket_reply;
reply_encpart.session = session_key;
if ((errcode = fetch_last_req_info(&client, &reply_encpart.last_req))) {
status = "FETCH_LAST_REQ";
goto errout;
}
reply_encpart.nonce = request->nonce;
reply_encpart.key_exp = client.expiration;
reply_encpart.flags = enc_tkt_reply.flags;
reply_encpart.server = ticket_reply.server;
/* copy the time fields EXCEPT for authtime; it's location
is used for ktime */
reply_encpart.times = enc_tkt_reply.times;
reply_encpart.times.authtime = authtime = kdc_time;
reply_encpart.caddrs = enc_tkt_reply.caddrs;
reply.enc_part.kvno = client_key->key_data_kvno;
/* Fetch the padata info to be returned */
errcode = return_padata(kdc_context, &client, request, &reply, client_key,
&encrypting_key);
if (errcode) {
status = "KDC_RETURN_PADATA";
goto errout;
}
/* now encode/encrypt the response */
reply.enc_part.enctype = encrypting_key.enctype;
errcode = krb5_encode_kdc_rep(kdc_context, KRB5_AS_REP, &reply_encpart,
&encrypting_key, &reply, response);
krb5_free_keyblock_contents(kdc_context, &encrypting_key);
encrypting_key.contents = 0;
if (errcode) {
status = "ENCODE_KDC_REP";
goto errout;
}
/* 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);
krb5_klog_syslog(LOG_INFO, "AS_REQ %s(%d): ISSUE: authtime %d, %s for %s",
fromstring, portnum, authtime, cname, sname);
#ifdef KRBCONF_KDC_MODIFIES_KDB
/*
* If we get this far, we successfully did the AS_REQ.
*/
client.last_success = kdc_time;
client.fail_auth_count = 0;
update_client = 1;
#endif /* KRBCONF_KDC_MODIFIES_KDB */
errout:
if (status)
krb5_klog_syslog(LOG_INFO, "AS_REQ %s(%d): %s: %s for %s%s%s",
fromstring, portnum, status,
cname ? cname : "<unknown client>",
sname ? sname : "<unknown server>",
errcode ? ", " : "",
errcode ? error_message(errcode) : "");
if (errcode) {
errcode -= ERROR_TABLE_BASE_krb5;
if (errcode < 0 || errcode > 128)
errcode = KRB_ERR_GENERIC;
errcode = prepare_error_as(request, errcode, &e_data, response);
}
krb5_free_keyblock_contents(kdc_context, &encrypting_key);
if (cname)
free(cname);
if (sname)
free(sname);
if (c_nprincs) {
#ifdef KRBCONF_KDC_MODIFIES_KDB
if (update_client) {
krb5_db_put_principal(kdc_context, &client, &c_nprincs);
/*
* ptooey. We want krb5_db_sync() or something like that.
*/
krb5_db_fini(kdc_context);
if (kdc_active_realm->realm_dbname)
krb5_db_set_name(kdc_active_realm->realm_context,
kdc_active_realm->realm_dbname);
krb5_db_init(kdc_context);
}
#endif /* KRBCONF_KDC_MODIFIES_KDB */
krb5_db_free_principal(kdc_context, &client, c_nprincs);
}
if (s_nprincs)
krb5_db_free_principal(kdc_context, &server, s_nprincs);
if (session_key)
krb5_free_keyblock(kdc_context, session_key);
if (ticket_reply.enc_part.ciphertext.data) {
memset(ticket_reply.enc_part.ciphertext.data , 0,
ticket_reply.enc_part.ciphertext.length);
free(ticket_reply.enc_part.ciphertext.data);
}
krb5_free_data_contents(kdc_context, &e_data);
return errcode;
}
static krb5_error_code
prepare_error_as (request, error, e_data, response)
register krb5_kdc_req *request;
int error;
krb5_data *e_data;
krb5_data **response;
{
krb5_error errpkt;
krb5_error_code retval;
krb5_data *scratch;
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;
errpkt.client = request->client;
errpkt.text.length = strlen(error_message(error+KRB5KDC_ERR_NONE))+1;
if (!(errpkt.text.data = malloc(errpkt.text.length)))
return ENOMEM;
(void) strcpy(errpkt.text.data, error_message(error+KRB5KDC_ERR_NONE));
if (!(scratch = (krb5_data *)malloc(sizeof(*scratch)))) {
free(errpkt.text.data);
return ENOMEM;
}
if (e_data && e_data->data) {
errpkt.e_data = *e_data;
} else {
errpkt.e_data.length = 0;
errpkt.e_data.data = 0;
}
retval = krb5_mk_error(kdc_context, &errpkt, scratch);
free(errpkt.text.data);
*response = scratch;
return retval;
}
|