static krb5_error_code
decrypt_fast_reply(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_pa_data **in_padata,
krb5_fast_response **response)
{
krb5_error_code retval = 0;
krb5_data scratch;
krb5_enc_data *encrypted_response = NULL;
krb5_pa_data *fx_reply = NULL;
krb5_fast_response *local_resp = NULL;
assert(state != NULL);
assert(state->armor_key);
fx_reply = krb5int_find_pa_data(context, in_padata, KRB5_PADATA_FX_FAST);
if (fx_reply == NULL)
retval = KRB5_ERR_FAST_REQUIRED;
TRACE_FAST_DECODE(context);
if (retval == 0) {
scratch.data = (char *) fx_reply->contents;
scratch.length = fx_reply->length;
retval = decode_krb5_pa_fx_fast_reply(&scratch, &encrypted_response);
}
scratch.data = NULL;
if (retval == 0) {
scratch.data = malloc(encrypted_response->ciphertext.length);
if (scratch.data == NULL)
retval = ENOMEM;
scratch.length = encrypted_response->ciphertext.length;
}
if (retval == 0)
retval = krb5_c_decrypt(context, state->armor_key,
KRB5_KEYUSAGE_FAST_REP, NULL,
encrypted_response, &scratch);
if (retval != 0)
k5_prependmsg(context, retval, _("Failed to decrypt FAST reply"));
if (retval == 0)
retval = decode_krb5_fast_response(&scratch, &local_resp);
if (retval == 0) {
if (local_resp->nonce != state->nonce) {
retval = KRB5_KDCREP_MODIFIED;
k5_setmsg(context, retval, _("nonce modified in FAST response: "
"KDC response modified"));
}
}
if (retval == 0) {
*response = local_resp;
local_resp = NULL;
}
if (scratch.data)
free(scratch.data);
if (encrypted_response)
krb5_free_enc_data(context, encrypted_response);
if (local_resp)
krb5_free_fast_response(context, local_resp);
return retval;
}
krb5_error_code
krb5int_fast_process_response(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_kdc_rep *resp,
krb5_keyblock **strengthen_key)
{
krb5_error_code retval = 0;
krb5_fast_response *fast_response = NULL;
krb5_data *encoded_ticket = NULL;
krb5_boolean cksum_valid;
krb5_clear_error_message(context);
*strengthen_key = NULL;
if (state->armor_key == 0)
return 0;
retval = decrypt_fast_reply(context, state, resp->padata,
&fast_response);
if (retval == 0) {
if (fast_response->finished == 0) {
retval = KRB5_KDCREP_MODIFIED;
krb5_set_error_message(context, retval,
_("FAST response missing finish message "
"in KDC reply"));
}
}
if (retval == 0)
retval = encode_krb5_ticket(resp->ticket, &encoded_ticket);
if (retval == 0)
retval = krb5_c_verify_checksum(context, state->armor_key,
KRB5_KEYUSAGE_FAST_FINISHED,
encoded_ticket,
&fast_response->finished->ticket_checksum,
&cksum_valid);
if (retval == 0 && cksum_valid == 0) {
retval = KRB5_KDCREP_MODIFIED;
krb5_set_error_message(context, retval,
_("Ticket modified in KDC reply"));
}
if (retval == 0) {
krb5_free_principal(context, resp->client);
resp->client = fast_response->finished->client;
fast_response->finished->client = NULL;
*strengthen_key = fast_response->strengthen_key;
fast_response->strengthen_key = NULL;
krb5_free_pa_data(context, resp->padata);
resp->padata = fast_response->padata;
fast_response->padata = NULL;
}
if (fast_response)
krb5_free_fast_response(context, fast_response);
if (encoded_ticket)
krb5_free_data(context, encoded_ticket);
return retval;
}
/*
* If state contains an armor key and *err_replyptr contains a FAST error,
* decode it and set *err_replyptr to the inner error and *out_padata to the
* padata in the FAST response. Otherwise, leave *err_replyptr alone and set
* *out_padata to the error e_data decoded as pa-data or typed-data, or to NULL
* if it doesn't decode as either. In either case, set *retry to indicate
* whether the client should try to make a follow-up request.
*/
krb5_error_code
krb5int_fast_process_error(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_error **err_replyptr,
krb5_pa_data ***out_padata,
krb5_boolean *retry)
{
krb5_error_code retval = 0;
krb5_error *err_reply = *err_replyptr;
krb5_pa_data *fx_error_pa;
krb5_pa_data **result = NULL;
krb5_data scratch = empty_data();
krb5_error *fx_error = NULL;
krb5_fast_response *fast_response = NULL;
if (out_padata)
*out_padata = NULL;
if (retry)
*retry = 0;
if (state->armor_key) {
retval = decode_krb5_padata_sequence(&err_reply->e_data, &result);
if (retval == 0)
retval = decrypt_fast_reply(context, state, result,
&fast_response);
if (retval) {
/*
* This can happen if the KDC does not understand FAST. We don't
* expect that, but treating it as the fatal error indicated by the
* KDC seems reasonable.
*/
if (retry != NULL)
*retry = 0;
krb5_free_pa_data(context, result);
return 0;
}
if (retval == 0) {
fx_error_pa = krb5int_find_pa_data(context, fast_response->padata,
KRB5_PADATA_FX_ERROR);
if (fx_error_pa == NULL) {
k5_setmsg(context, KRB5KDC_ERR_PREAUTH_FAILED,
_("Expecting FX_ERROR pa-data inside FAST "
"container"));
retval = KRB5KDC_ERR_PREAUTH_FAILED;
}
}
if (retval == 0) {
scratch = make_data(fx_error_pa->contents, fx_error_pa->length);
retval = decode_krb5_error(&scratch, &fx_error);
}
if (retval == 0) {
krb5_free_error(context, err_reply);
*err_replyptr = fx_error;
fx_error = NULL;
if (out_padata) {
*out_padata = fast_response->padata;
fast_response->padata = NULL;
}
/*
* If there is more than the fx_error padata, then we want
* to retry the error if a cookie is present
*/
if (retry != NULL) {
*retry = (*out_padata)[1] != NULL;
if (krb5int_find_pa_data(context, *out_padata,
KRB5_PADATA_FX_COOKIE) == NULL)
*retry = 0;
}
}
} else { /*not FAST*/
/* Possibly retry if there's any e_data to process. */
if (retry)
*retry = (err_reply->e_data.length > 0);
/* Try to decode e_data as pa-data or typed-data for out_padata. */
if (out_padata) {
retval = decode_krb5_padata_sequence(&err_reply->e_data,
out_padata);
if (retval != 0) {
(void)decode_krb5_typed_data(&err_reply->e_data, out_padata);
retval = 0;
}
}
}
krb5_free_pa_data(context, result);
krb5_free_fast_response(context, fast_response);
if (fx_error)
krb5_free_error(context, fx_error);
return retval;
}
/*
* FAST separates two concepts: the set of padata we're using to
* decide what pre-auth mechanisms to use and the set of padata we're
* making available to mechanisms in order for them to respond to an
* error. The plugin interface in March 2009 does not permit
* separating these concepts for the plugins. This function makes
* both available for future revisions to the plugin interface. It
* also re-encodes the padata from the current error as a encoded
* typed-data and puts that in the e_data field. That will allow
* existing plugins with the old interface to find the error data.
* The output parameter out_padata contains the padata from the error
* whenever padata is available (all the time with fast).
*/
krb5_error_code
krb5int_fast_process_error(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_error **err_replyptr,
krb5_pa_data ***out_padata,
krb5_boolean *retry)
{
krb5_error_code retval = 0;
krb5_error *err_reply = *err_replyptr;
*out_padata = NULL;
*retry = 0;
if (state->armor_key) {
krb5_pa_data *fx_error_pa;
krb5_pa_data **result = NULL;
krb5_data scratch, *encoded_td = NULL;
krb5_error *fx_error = NULL;
krb5_fast_response *fast_response = NULL;
retval = decode_krb5_padata_sequence(&err_reply->e_data, &result);
if (retval == 0)
retval = decrypt_fast_reply(context, state, result,
&fast_response);
if (retval) {
/*
* This can happen if the KDC does not understand FAST. We don't
* expect that, but treating it as the fatal error indicated by the
* KDC seems reasonable.
*/
*retry = 0;
krb5_free_pa_data(context, result);
return 0;
}
krb5_free_pa_data(context, result);
result = NULL;
if (retval == 0) {
fx_error_pa = krb5int_find_pa_data(context, fast_response->padata,
KRB5_PADATA_FX_ERROR);
if (fx_error_pa == NULL) {
krb5_set_error_message(context, KRB5KDC_ERR_PREAUTH_FAILED,
"Expecting FX_ERROR pa-data inside "
"FAST container");
retval = KRB5KDC_ERR_PREAUTH_FAILED;
}
}
if (retval == 0) {
scratch.data = (char *) fx_error_pa->contents;
scratch.length = fx_error_pa->length;
retval = decode_krb5_error(&scratch, &fx_error);
}
/*
* krb5_pa_data and krb5_typed_data are safe to cast between:
* they have the same type fields in the same order.
* (krb5_preauthtype is a krb5_int32). If krb5_typed_data is
* ever changed then this will need to be a copy not a cast.
*/
if (retval == 0)
retval = encode_krb5_typed_data((const krb5_typed_data **)
fast_response->padata,
&encoded_td);
if (retval == 0) {
fx_error->e_data = *encoded_td;
free(encoded_td); /*contents owned by fx_error*/
encoded_td = NULL;
krb5_free_error(context, err_reply);
*err_replyptr = fx_error;
fx_error = NULL;
*out_padata = fast_response->padata;
fast_response->padata = NULL;
/*
* If there is more than the fx_error padata, then we want
* to retry the error if a cookie is present
*/
*retry = (*out_padata)[1] != NULL;
if (krb5int_find_pa_data(context, *out_padata,
KRB5_PADATA_FX_COOKIE) == NULL)
*retry = 0;
}
if (fx_error)
krb5_free_error(context, fx_error);
krb5_free_fast_response(context, fast_response);
} else { /*not FAST*/
*retry = (err_reply->e_data.length > 0);
if ((err_reply->error == KDC_ERR_PREAUTH_REQUIRED ||
err_reply->error == KDC_ERR_PREAUTH_FAILED) &&
err_reply->e_data.length) {
krb5_pa_data **result = NULL;
retval = decode_krb5_padata_sequence(&err_reply->e_data, &result);
if (retval == 0) {
*out_padata = result;
return 0;
}
krb5_free_pa_data(context, result);
krb5_set_error_message(context, retval,
"Error decoding padata in error reply");
return retval;
}
}
return retval;
}