static krb5_error_code
tgs_build_reply(krb5_context context,
krb5_kdc_configuration *config,
KDC_REQ *req,
KDC_REQ_BODY *b,
hdb_entry_ex *krbtgt,
krb5_enctype krbtgt_etype,
krb5_ticket *ticket,
krb5_data *reply,
const char *from,
const char **e_text,
AuthorizationData *auth_data,
const struct sockaddr *from_addr,
int datagram_reply)
{
krb5_error_code ret;
krb5_principal cp = NULL, sp = NULL;
krb5_principal client_principal = NULL;
char *spn = NULL, *cpn = NULL;
hdb_entry_ex *server = NULL, *client = NULL;
EncTicketPart *tgt = &ticket->ticket;
KRB5SignedPathPrincipals *spp = NULL;
const EncryptionKey *ekey;
krb5_keyblock sessionkey;
krb5_kvno kvno;
krb5_data rspac;
int cross_realm = 0;
PrincipalName *s;
Realm r;
int nloop = 0;
EncTicketPart adtkt;
char opt_str[128];
int require_signedpath = 0;
memset(&sessionkey, 0, sizeof(sessionkey));
memset(&adtkt, 0, sizeof(adtkt));
krb5_data_zero(&rspac);
s = b->sname;
r = b->realm;
if(b->kdc_options.enc_tkt_in_skey){
Ticket *t;
hdb_entry_ex *uu;
krb5_principal p;
Key *uukey;
if(b->additional_tickets == NULL ||
b->additional_tickets->len == 0){
ret = KRB5KDC_ERR_BADOPTION; /* ? */
kdc_log(context, config, 0,
"No second ticket present in request");
goto out;
}
t = &b->additional_tickets->val[0];
if(!get_krbtgt_realm(&t->sname)){
kdc_log(context, config, 0,
"Additional ticket is not a ticket-granting ticket");
ret = KRB5KDC_ERR_POLICY;
goto out;
}
_krb5_principalname2krb5_principal(context, &p, t->sname, t->realm);
ret = _kdc_db_fetch(context, config, p,
HDB_F_GET_CLIENT|HDB_F_GET_SERVER,
NULL, &uu);
krb5_free_principal(context, p);
if(ret){
if (ret == HDB_ERR_NOENTRY)
ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
goto out;
}
ret = hdb_enctype2key(context, &uu->entry,
t->enc_part.etype, &uukey);
if(ret){
_kdc_free_ent(context, uu);
ret = KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */
goto out;
}
ret = krb5_decrypt_ticket(context, t, &uukey->key, &adtkt, 0);
_kdc_free_ent(context, uu);
if(ret)
goto out;
ret = verify_flags(context, config, &adtkt, spn);
if (ret)
goto out;
s = &adtkt.cname;
r = adtkt.crealm;
}
_krb5_principalname2krb5_principal(context, &sp, *s, r);
ret = krb5_unparse_name(context, sp, &spn);
if (ret)
goto out;
_krb5_principalname2krb5_principal(context, &cp, tgt->cname, tgt->crealm);
ret = krb5_unparse_name(context, cp, &cpn);
if (ret)
goto out;
unparse_flags (KDCOptions2int(b->kdc_options),
asn1_KDCOptions_units(),
opt_str, sizeof(opt_str));
if(*opt_str)
kdc_log(context, config, 0,
"TGS-REQ %s from %s for %s [%s]",
cpn, from, spn, opt_str);
else
kdc_log(context, config, 0,
"TGS-REQ %s from %s for %s", cpn, from, spn);
/*
* Fetch server
*/
server_lookup:
ret = _kdc_db_fetch(context, config, sp, HDB_F_GET_SERVER, NULL, &server);
if(ret){
const char *new_rlm;
Realm req_rlm;
krb5_realm *realms;
if ((req_rlm = get_krbtgt_realm(&sp->name)) != NULL) {
if(nloop++ < 2) {
new_rlm = find_rpath(context, tgt->crealm, req_rlm);
if(new_rlm) {
kdc_log(context, config, 5, "krbtgt for realm %s "
"not found, trying %s",
req_rlm, new_rlm);
krb5_free_principal(context, sp);
free(spn);
krb5_make_principal(context, &sp, r,
KRB5_TGS_NAME, new_rlm, NULL);
ret = krb5_unparse_name(context, sp, &spn);
if (ret)
goto out;
goto server_lookup;
}
}
} else if(need_referral(context, sp, &realms)) {
if (strcmp(realms[0], sp->realm) != 0) {
kdc_log(context, config, 5,
"Returning a referral to realm %s for "
"server %s that was not found",
realms[0], spn);
krb5_free_principal(context, sp);
free(spn);
krb5_make_principal(context, &sp, r, KRB5_TGS_NAME,
realms[0], NULL);
ret = krb5_unparse_name(context, sp, &spn);
if (ret)
goto out;
krb5_free_host_realm(context, realms);
goto server_lookup;
}
krb5_free_host_realm(context, realms);
}
kdc_log(context, config, 0,
"Server not found in database: %s: %s", spn,
krb5_get_err_text(context, ret));
if (ret == HDB_ERR_NOENTRY)
ret = KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
goto out;
}
ret = _kdc_db_fetch(context, config, cp, HDB_F_GET_CLIENT, NULL, &client);
if(ret) {
const char *krbtgt_realm;
/*
* If the client belongs to the same realm as our krbtgt, it
* should exist in the local database.
*
*/
krbtgt_realm =
krb5_principal_get_comp_string(context,
krbtgt->entry.principal, 1);
if(strcmp(krb5_principal_get_realm(context, cp), krbtgt_realm) == 0) {
if (ret == HDB_ERR_NOENTRY)
ret = KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
kdc_log(context, config, 1, "Client no longer in database: %s",
cpn);
goto out;
}
kdc_log(context, config, 1, "Client not found in database: %s: %s",
cpn, krb5_get_err_text(context, ret));
cross_realm = 1;
}
/*
* Check that service is in the same realm as the krbtgt. If its
* not the same, its someone that is using a uni-directional trust
* backward.
*/
if (strcmp(krb5_principal_get_realm(context, sp),
krb5_principal_get_comp_string(context,
krbtgt->entry.principal,
1)) != 0) {
char *tpn;
ret = krb5_unparse_name(context, krbtgt->entry.principal, &tpn);
kdc_log(context, config, 0,
"Request with wrong krbtgt: %s",
(ret == 0) ? tpn : "<unknown>");
if(ret == 0)
free(tpn);
ret = KRB5KRB_AP_ERR_NOT_US;
goto out;
}
/*
*
*/
client_principal = cp;
if (client) {
const PA_DATA *sdata;
int i = 0;
sdata = _kdc_find_padata(req, &i, KRB5_PADATA_S4U2SELF);
if (sdata) {
krb5_crypto crypto;
krb5_data datack;
PA_S4U2Self self;
char *selfcpn = NULL;
const char *str;
ret = decode_PA_S4U2Self(sdata->padata_value.data,
sdata->padata_value.length,
&self, NULL);
if (ret) {
kdc_log(context, config, 0, "Failed to decode PA-S4U2Self");
goto out;
}
ret = _krb5_s4u2self_to_checksumdata(context, &self, &datack);
if (ret)
goto out;
ret = krb5_crypto_init(context, &tgt->key, 0, &crypto);
if (ret) {
free_PA_S4U2Self(&self);
krb5_data_free(&datack);
kdc_log(context, config, 0, "krb5_crypto_init failed: %s",
krb5_get_err_text(context, ret));
goto out;
}
ret = krb5_verify_checksum(context,
crypto,
KRB5_KU_OTHER_CKSUM,
datack.data,
datack.length,
&self.cksum);
krb5_data_free(&datack);
krb5_crypto_destroy(context, crypto);
if (ret) {
free_PA_S4U2Self(&self);
kdc_log(context, config, 0,
"krb5_verify_checksum failed for S4U2Self: %s",
krb5_get_err_text(context, ret));
goto out;
}
ret = _krb5_principalname2krb5_principal(context,
&client_principal,
self.name,
self.realm);
free_PA_S4U2Self(&self);
if (ret)
goto out;
ret = krb5_unparse_name(context, client_principal, &selfcpn);
if (ret)
goto out;
/*
* Check that service doing the impersonating is
* requesting a ticket to it-self.
*/
if (krb5_principal_compare(context, cp, sp) != TRUE) {
kdc_log(context, config, 0, "S4U2Self: %s is not allowed "
"to impersonate some other user "
"(tried for user %s to service %s)",
cpn, selfcpn, spn);
free(selfcpn);
ret = KRB5KDC_ERR_BADOPTION; /* ? */
goto out;
}
/*
* If the service isn't trusted for authentication to
* delegation, remove the forward flag.
*/
if (client->entry.flags.trusted_for_delegation) {
str = "[forwardable]";
} else {
b->kdc_options.forwardable = 0;
str = "";
}
kdc_log(context, config, 0, "s4u2self %s impersonating %s to "
"service %s %s", cpn, selfcpn, spn, str);
free(selfcpn);
}
}
/*
* Constrained delegation
*/
if (client != NULL
&& b->additional_tickets != NULL
&& b->additional_tickets->len != 0
&& b->kdc_options.enc_tkt_in_skey == 0)
{
Key *clientkey;
Ticket *t;
char *str;
t = &b->additional_tickets->val[0];
ret = hdb_enctype2key(context, &client->entry,
t->enc_part.etype, &clientkey);
if(ret){
ret = KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */
goto out;
}
ret = krb5_decrypt_ticket(context, t, &clientkey->key, &adtkt, 0);
if (ret) {
kdc_log(context, config, 0,
"failed to decrypt ticket for "
"constrained delegation from %s to %s ", spn, cpn);
goto out;
}
/* check that ticket is valid */
if (adtkt.flags.forwardable == 0) {
kdc_log(context, config, 0,
"Missing forwardable flag on ticket for "
"constrained delegation from %s to %s ", spn, cpn);
ret = KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */
goto out;
}
ret = check_constrained_delegation(context, config, client, sp);
if (ret) {
kdc_log(context, config, 0,
"constrained delegation from %s to %s not allowed",
spn, cpn);
goto out;
}
ret = _krb5_principalname2krb5_principal(context,
&client_principal,
adtkt.cname,
adtkt.crealm);
if (ret)
goto out;
ret = krb5_unparse_name(context, client_principal, &str);
if (ret)
goto out;
ret = verify_flags(context, config, &adtkt, str);
if (ret) {
free(str);
goto out;
}
/*
* Check KRB5SignedPath in authorization data and add new entry to
* make sure servers can't fake a ticket to us.
*/
ret = check_KRB5SignedPath(context,
config,
krbtgt,
&adtkt,
&spp,
1);
if (ret) {
kdc_log(context, config, 0,
"KRB5SignedPath check from service %s failed "
"for delegation to %s for client %s "
"from %s failed with %s",
spn, str, cpn, from, krb5_get_err_text(context, ret));
free(str);
goto out;
}
kdc_log(context, config, 0, "constrained delegation for %s "
"from %s to %s", str, cpn, spn);
free(str);
/*
* Also require that the KDC have issue the service's krbtgt
* used to do the request.
*/
require_signedpath = 1;
}
/*
* Check flags
*/
ret = _kdc_check_flags(context, config,
client, cpn,
server, spn,
FALSE);
if(ret)
goto out;
if((b->kdc_options.validate || b->kdc_options.renew) &&
!krb5_principal_compare(context,
krbtgt->entry.principal,
server->entry.principal)){
kdc_log(context, config, 0, "Inconsistent request.");
ret = KRB5KDC_ERR_SERVER_NOMATCH;
goto out;
}
/* check for valid set of addresses */
if(!_kdc_check_addresses(context, config, tgt->caddr, from_addr)) {
ret = KRB5KRB_AP_ERR_BADADDR;
kdc_log(context, config, 0, "Request from wrong address");
goto out;
}
/*
* Select enctype, return key and kvno.
*/
{
krb5_enctype etype;
if(b->kdc_options.enc_tkt_in_skey) {
int i;
ekey = &adtkt.key;
for(i = 0; i < b->etype.len; i++)
if (b->etype.val[i] == adtkt.key.keytype)
break;
if(i == b->etype.len) {
krb5_clear_error_string(context);
return KRB5KDC_ERR_ETYPE_NOSUPP;
}
etype = b->etype.val[i];
kvno = 0;
} else {
Key *skey;
ret = _kdc_find_etype(context, server, b->etype.val, b->etype.len,
&skey, &etype);
if(ret) {
kdc_log(context, config, 0,
"Server (%s) has no support for etypes", spp);
return ret;
}
ekey = &skey->key;
kvno = server->entry.kvno;
}
ret = krb5_generate_random_keyblock(context, etype, &sessionkey);
if (ret)
goto out;
}
/* check PAC if not cross realm and if there is one */
if (!cross_realm) {
Key *tkey;
ret = hdb_enctype2key(context, &krbtgt->entry,
krbtgt_etype, &tkey);
if(ret) {
kdc_log(context, config, 0,
"Failed to find key for krbtgt PAC check");
goto out;
}
ret = check_PAC(context, config, client_principal,
client, server, ekey, &tkey->key,
tgt, &rspac, &require_signedpath);
if (ret) {
kdc_log(context, config, 0,
"Verify PAC failed for %s (%s) from %s with %s",
spn, cpn, from, krb5_get_err_text(context, ret));
goto out;
}
}
/* also check the krbtgt for signature */
ret = check_KRB5SignedPath(context,
config,
krbtgt,
tgt,
&spp,
require_signedpath);
if (ret) {
kdc_log(context, config, 0,
"KRB5SignedPath check failed for %s (%s) from %s with %s",
spn, cpn, from, krb5_get_err_text(context, ret));
goto out;
}
/*
*
*/
ret = tgs_make_reply(context,
config,
b,
client_principal,
tgt,
ekey,
&sessionkey,
kvno,
auth_data,
server,
spn,
client,
cp,
krbtgt,
krbtgt_etype,
spp,
&rspac,
e_text,
reply);
out:
free(spn);
free(cpn);
krb5_data_free(&rspac);
krb5_free_keyblock_contents(context, &sessionkey);
if(server)
_kdc_free_ent(context, server);
if(client)
_kdc_free_ent(context, client);
if (client_principal && client_principal != cp)
krb5_free_principal(context, client_principal);
if (cp)
krb5_free_principal(context, cp);
if (sp)
krb5_free_principal(context, sp);
free_EncTicketPart(&adtkt);
return ret;
}
KRB5_LIB_FUNCTION krb5_error_code KRB5_LIB_CALL
krb5_verify_ap_req2(krb5_context context,
krb5_auth_context *auth_context,
krb5_ap_req *ap_req,
krb5_const_principal server,
krb5_keyblock *keyblock,
krb5_flags flags,
krb5_flags *ap_req_options,
krb5_ticket **ticket,
krb5_key_usage usage)
{
krb5_ticket *t;
krb5_auth_context ac;
krb5_error_code ret;
EtypeList etypes;
memset(&etypes, 0, sizeof(etypes));
if(ticket)
*ticket = NULL;
if (auth_context && *auth_context) {
ac = *auth_context;
} else {
ret = krb5_auth_con_init(context, &ac);
if (ret)
return ret;
}
t = calloc(1, sizeof(*t));
if (t == NULL) {
ret = ENOMEM;
krb5_clear_error_message(context);
goto out;
}
if (ap_req->ap_options.use_session_key && ac->keyblock){
ret = krb5_decrypt_ticket(context, &ap_req->ticket,
ac->keyblock,
&t->ticket,
flags);
krb5_free_keyblock(context, ac->keyblock);
ac->keyblock = NULL;
}else
ret = krb5_decrypt_ticket(context, &ap_req->ticket,
keyblock,
&t->ticket,
flags);
if(ret)
goto out;
ret = _krb5_principalname2krb5_principal(context,
&t->server,
ap_req->ticket.sname,
ap_req->ticket.realm);
if (ret) goto out;
ret = _krb5_principalname2krb5_principal(context,
&t->client,
t->ticket.cname,
t->ticket.crealm);
if (ret) goto out;
ret = decrypt_authenticator(context,
&t->ticket.key,
&ap_req->authenticator,
ac->authenticator,
usage);
if (ret)
goto out;
{
krb5_principal p1, p2;
krb5_boolean res;
_krb5_principalname2krb5_principal(context,
&p1,
ac->authenticator->cname,
ac->authenticator->crealm);
_krb5_principalname2krb5_principal(context,
&p2,
t->ticket.cname,
t->ticket.crealm);
res = krb5_principal_compare(context, p1, p2);
krb5_free_principal(context, p1);
krb5_free_principal(context, p2);
if (!res) {
ret = KRB5KRB_AP_ERR_BADMATCH;
krb5_clear_error_message(context);
goto out;
}
}
/* check addresses */
if (t->ticket.caddr
&& ac->remote_address
&& !krb5_address_search(context,
ac->remote_address,
t->ticket.caddr)) {
ret = KRB5KRB_AP_ERR_BADADDR;
krb5_clear_error_message(context);
goto out;
}
/* check timestamp in authenticator */
{
krb5_timestamp now;
krb5_timeofday(context, &now);
if (krb5_time_abs(ac->authenticator->ctime, now) > context->max_skew) {
ret = KRB5KRB_AP_ERR_SKEW;
krb5_clear_error_message(context);
goto out;
}
}
if (ac->authenticator->seq_number)
krb5_auth_con_setremoteseqnumber(context, ac,
*ac->authenticator->seq_number);
/* XXX - Xor sequence numbers */
if (ac->authenticator->subkey) {
ret = krb5_auth_con_setremotesubkey(context, ac,
ac->authenticator->subkey);
if (ret)
goto out;
}
ret = find_etypelist(context, ac, &etypes);
if (ret)
goto out;
ac->keytype = (krb5_keytype)ETYPE_NULL;
if (etypes.val) {
size_t i;
for (i = 0; i < etypes.len; i++) {
if (krb5_enctype_valid(context, etypes.val[i]) == 0) {
ac->keytype = etypes.val[i];
break;
}
}
}
/* save key */
ret = krb5_copy_keyblock(context, &t->ticket.key, &ac->keyblock);
if (ret) goto out;
if (ap_req_options) {
*ap_req_options = 0;
if (ac->keytype != ETYPE_NULL)
*ap_req_options |= AP_OPTS_USE_SUBKEY;
if (ap_req->ap_options.use_session_key)
*ap_req_options |= AP_OPTS_USE_SESSION_KEY;
if (ap_req->ap_options.mutual_required)
*ap_req_options |= AP_OPTS_MUTUAL_REQUIRED;
}
if(ticket)
*ticket = t;
else
krb5_free_ticket(context, t);
if (auth_context) {
if (*auth_context == NULL)
*auth_context = ac;
} else
krb5_auth_con_free(context, ac);
free_EtypeList(&etypes);
return 0;
out:
free_EtypeList(&etypes);
if (t)
krb5_free_ticket(context, t);
if (auth_context == NULL || *auth_context == NULL)
krb5_auth_con_free(context, ac);
return ret;
}
