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/*
* lib/krb5/krb/send_tgs.c
*
* Copyright 1990,1991,2009 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.
*
*
* krb5_send_tgs()
*/
#include "k5-int.h"
/*
Constructs a TGS request
options is used for the options in the KRB_TGS_REQ.
timestruct values are used for from, till, rtime " " "
enctype is used for enctype " " ", and to encrypt the authorization data,
sname is used for sname " " "
addrs, if non-NULL, is used for addresses " " "
authorization_dat, if non-NULL, is used for authorization_dat " " "
second_ticket, if required by options, is used for the 2nd ticket in the req.
in_cred is used for the ticket & session key in the KRB_AP_REQ header " " "
(the KDC realm is extracted from in_cred->server's realm)
The response is placed into *rep.
rep->response.data is set to point at allocated storage which should be
freed by the caller when finished.
returns system errors
*/
static krb5_error_code
tgs_construct_tgsreq(krb5_context context, krb5_data *in_data,
krb5_creds *in_cred, krb5_data *outbuf, krb5_keyblock *subkey)
{
krb5_cksumtype cksumtype;
krb5_error_code retval;
krb5_checksum checksum;
krb5_authenticator authent;
krb5_ap_req request;
krb5_data * scratch = NULL;
krb5_data * toutbuf = NULL;
checksum.contents = NULL;
request.authenticator.ciphertext.data = NULL;
request.authenticator.kvno = 0;
request.ap_options = 0;
request.ticket = 0;
switch (in_cred->keyblock.enctype) {
case ENCTYPE_DES_CBC_CRC:
case ENCTYPE_DES_CBC_MD4:
case ENCTYPE_DES_CBC_MD5:
case ENCTYPE_ARCFOUR_HMAC:
case ENCTYPE_ARCFOUR_HMAC_EXP:
cksumtype = context->kdc_req_sumtype;
break;
default:
retval = krb5int_c_mandatory_cksumtype(context, in_cred->keyblock.enctype, &cksumtype);
if (retval)
goto cleanup;
}
/* Generate checksum */
if ((retval = krb5_c_make_checksum(context, cksumtype,
&in_cred->keyblock,
KRB5_KEYUSAGE_TGS_REQ_AUTH_CKSUM,
in_data, &checksum))) {
free(checksum.contents);
goto cleanup;
}
/* gen authenticator */
authent.subkey = subkey; /*owned by caller*/
authent.seq_number = 0;
authent.checksum = &checksum;
authent.client = in_cred->client;
authent.authorization_data = in_cred->authdata;
if ((retval = krb5_us_timeofday(context, &authent.ctime,
&authent.cusec)))
goto cleanup;
/* encode the authenticator */
if ((retval = encode_krb5_authenticator(&authent, &scratch)))
goto cleanup;
free(checksum.contents);
checksum.contents = NULL;
if ((retval = decode_krb5_ticket(&(in_cred)->ticket, &request.ticket)))
/* Cleanup scratch and scratch data */
goto cleanup;
/* call the encryption routine */
if ((retval = krb5_encrypt_helper(context, &in_cred->keyblock,
KRB5_KEYUSAGE_TGS_REQ_AUTH,
scratch, &request.authenticator)))
goto cleanup;
if (!(retval = encode_krb5_ap_req(&request, &toutbuf))) {
*outbuf = *toutbuf;
free(toutbuf);
}
memset(request.authenticator.ciphertext.data, 0,
request.authenticator.ciphertext.length);
free(request.authenticator.ciphertext.data);
request.authenticator.ciphertext.length = 0;
request.authenticator.ciphertext.data = 0;
cleanup:
if (request.ticket)
krb5_free_ticket(context, request.ticket);
if (scratch != NULL && scratch->data != NULL) {
zap(scratch->data, scratch->length);
free(scratch->data);
}
free(scratch);
return retval;
}
/*
* Note that this function fills in part of rep even on failure.
*/
krb5_error_code
krb5int_send_tgs(krb5_context context, krb5_flags kdcoptions,
const krb5_ticket_times *timestruct, const krb5_enctype *ktypes,
krb5_const_principal sname, krb5_address *const *addrs,
krb5_authdata *const *authorization_data,
krb5_pa_data *const *padata, const krb5_data *second_ticket,
krb5_creds *in_cred, krb5_response *rep, krb5_keyblock **subkey)
{
krb5_error_code retval;
krb5_kdc_req tgsreq;
krb5_data *scratch, scratch2;
krb5_ticket *sec_ticket = 0;
krb5_ticket *sec_ticket_arr[2];
krb5_timestamp time_now;
krb5_pa_data **combined_padata;
krb5_pa_data ap_req_padata;
int tcp_only = 0, use_master;
krb5_keyblock *local_subkey = NULL;
assert (subkey != NULL);
*subkey = NULL;
/*
* in_creds MUST be a valid credential NOT just a partially filled in
* place holder for us to get credentials for the caller.
*/
if (!in_cred->ticket.length)
return(KRB5_NO_TKT_SUPPLIED);
memset(&tgsreq, 0, sizeof(tgsreq));
tgsreq.kdc_options = kdcoptions;
tgsreq.server = (krb5_principal) sname;
tgsreq.from = timestruct->starttime;
tgsreq.till = timestruct->endtime ? timestruct->endtime : in_cred->times.endtime;
tgsreq.authorization_data.ciphertext.data = NULL;
tgsreq.rtime = timestruct->renew_till;
if ((retval = krb5_timeofday(context, &time_now)))
return(retval);
/* XXX we know they are the same size... */
rep->expected_nonce = tgsreq.nonce = (krb5_int32) time_now;
rep->request_time = time_now;
rep->message_type = KRB5_ERROR; /*caller only uses the response
* element on successful return*/
tgsreq.addresses = (krb5_address **) addrs;
/* Generate subkey*/
if ((retval = krb5_generate_subkey( context, &in_cred->keyblock,
&local_subkey)) != 0)
return retval;
if (authorization_data) {
/* need to encrypt it in the request */
if ((retval = encode_krb5_authdata(authorization_data, &scratch)))
goto send_tgs_error_1;
if ((retval = krb5_encrypt_helper(context, local_subkey,
KRB5_KEYUSAGE_TGS_REQ_AD_SUBKEY,
scratch,
&tgsreq.authorization_data))) {
free(tgsreq.authorization_data.ciphertext.data);
krb5_free_data(context, scratch);
goto send_tgs_error_1;
}
krb5_free_data(context, scratch);
}
/* Get the encryption types list */
if (ktypes) {
/* Check passed ktypes and make sure they're valid. */
for (tgsreq.nktypes = 0; ktypes[tgsreq.nktypes]; tgsreq.nktypes++) {
if (!krb5_c_valid_enctype(ktypes[tgsreq.nktypes]))
return KRB5_PROG_ETYPE_NOSUPP;
}
tgsreq.ktype = (krb5_enctype *)ktypes;
} else {
/* Get the default ktypes */
krb5_get_tgs_ktypes(context, sname, &(tgsreq.ktype));
for(tgsreq.nktypes = 0; tgsreq.ktype[tgsreq.nktypes]; tgsreq.nktypes++);
}
if (second_ticket) {
if ((retval = decode_krb5_ticket(second_ticket, &sec_ticket)))
goto send_tgs_error_1;
sec_ticket_arr[0] = sec_ticket;
sec_ticket_arr[1] = 0;
tgsreq.second_ticket = sec_ticket_arr;
} else
tgsreq.second_ticket = 0;
/* encode the body; then checksum it */
if ((retval = encode_krb5_kdc_req_body(&tgsreq, &scratch)))
goto send_tgs_error_2;
/*
* Get an ap_req.
*/
if ((retval = tgs_construct_tgsreq(context, scratch, in_cred,
&scratch2, local_subkey))) {
krb5_free_data(context, scratch);
goto send_tgs_error_2;
}
krb5_free_data(context, scratch);
ap_req_padata.pa_type = KRB5_PADATA_AP_REQ;
ap_req_padata.length = scratch2.length;
ap_req_padata.contents = (krb5_octet *)scratch2.data;
/* combine in any other supplied padata */
if (padata) {
krb5_pa_data * const * counter;
register unsigned int i = 0;
for (counter = padata; *counter; counter++, i++);
combined_padata = malloc((i+2) * sizeof(*combined_padata));
if (!combined_padata) {
free(ap_req_padata.contents);
retval = ENOMEM;
goto send_tgs_error_2;
}
combined_padata[0] = &ap_req_padata;
for (i = 1, counter = padata; *counter; counter++, i++)
combined_padata[i] = (krb5_pa_data *) *counter;
combined_padata[i] = 0;
} else {
combined_padata = (krb5_pa_data **)malloc(2*sizeof(*combined_padata));
if (!combined_padata) {
free(ap_req_padata.contents);
retval = ENOMEM;
goto send_tgs_error_2;
}
combined_padata[0] = &ap_req_padata;
combined_padata[1] = 0;
}
tgsreq.padata = combined_padata;
/* the TGS_REQ is assembled in tgsreq, so encode it */
if ((retval = encode_krb5_tgs_req(&tgsreq, &scratch))) {
free(ap_req_padata.contents);
free(combined_padata);
goto send_tgs_error_2;
}
free(ap_req_padata.contents);
free(combined_padata);
/* now send request & get response from KDC */
send_again:
use_master = 0;
retval = krb5_sendto_kdc(context, scratch,
krb5_princ_realm(context, sname),
&rep->response, &use_master, tcp_only);
if (retval == 0) {
if (krb5_is_krb_error(&rep->response)) {
if (!tcp_only) {
krb5_error *err_reply;
retval = decode_krb5_error(&rep->response, &err_reply);
if (retval)
goto send_tgs_error_3;
if (err_reply->error == KRB_ERR_RESPONSE_TOO_BIG) {
tcp_only = 1;
krb5_free_error(context, err_reply);
free(rep->response.data);
rep->response.data = NULL;
goto send_again;
}
krb5_free_error(context, err_reply);
send_tgs_error_3:
;
}
rep->message_type = KRB5_ERROR;
} else if (krb5_is_tgs_rep(&rep->response)) {
rep->message_type = KRB5_TGS_REP;
*subkey = local_subkey;
} else /* XXX: assume it's an error */
rep->message_type = KRB5_ERROR;
}
krb5_free_data(context, scratch);
send_tgs_error_2:;
if (sec_ticket)
krb5_free_ticket(context, sec_ticket);
send_tgs_error_1:;
if (ktypes == NULL)
free(tgsreq.ktype);
if (tgsreq.authorization_data.ciphertext.data) {
memset(tgsreq.authorization_data.ciphertext.data, 0,
tgsreq.authorization_data.ciphertext.length);
free(tgsreq.authorization_data.ciphertext.data);
}
if (rep->message_type != KRB5_TGS_REP && local_subkey){
krb5_free_keyblock(context, *subkey);
}
return retval;
}
|