static krb5_error_code
ec_process(krb5_context context, krb5_clpreauth_moddata moddata,
krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt,
krb5_clpreauth_callbacks cb,
krb5_clpreauth_rock rock, krb5_kdc_req *request,
krb5_data *encoded_request_body,
krb5_data *encoded_previous_request, krb5_pa_data *padata,
krb5_prompter_fct prompter, void *prompter_data,
krb5_pa_data ***out_padata)
{
krb5_error_code retval = 0;
krb5_keyblock *challenge_key = NULL, *armor_key, *as_key;
armor_key = cb->fast_armor(context, rock);
if (armor_key == NULL)
return ENOENT;
retval = cb->get_as_key(context, rock, &as_key);
if (retval == 0 && padata->length) {
krb5_enc_data *enc = NULL;
krb5_data scratch;
scratch.length = padata->length;
scratch.data = (char *) padata->contents;
retval = krb5_c_fx_cf2_simple(context,armor_key, "kdcchallengearmor",
as_key, "challengelongterm",
&challenge_key);
if (retval == 0)
retval = decode_krb5_enc_data(&scratch, &enc);
scratch.data = NULL;
if (retval == 0) {
scratch.data = malloc(enc->ciphertext.length);
scratch.length = enc->ciphertext.length;
if (scratch.data == NULL)
retval = ENOMEM;
}
if (retval == 0)
retval = krb5_c_decrypt(context, challenge_key,
KRB5_KEYUSAGE_ENC_CHALLENGE_KDC, NULL,
enc, &scratch);
/*
* Per draft 11 of the preauth framework, the client MAY but is not
* required to actually check the timestamp from the KDC other than to
* confirm it decrypts. This code does not perform that check.
*/
if (scratch.data)
krb5_free_data_contents(context, &scratch);
/* If we had a callback to assert that the KDC is verified, we would
* call it here. */
if (enc)
krb5_free_enc_data(context, enc);
} else if (retval == 0) { /*No padata; we send*/
krb5_enc_data enc;
krb5_pa_data **pa = NULL;
krb5_data *encoded_ts = NULL;
krb5_pa_enc_ts ts;
enc.ciphertext.data = NULL;
/* Use the timestamp from the preauth-required error if possible.
* This time should always be secured by the FAST channel. */
retval = cb->get_preauth_time(context, rock, FALSE, &ts.patimestamp,
&ts.pausec);
if (retval == 0)
retval = encode_krb5_pa_enc_ts(&ts, &encoded_ts);
if (retval == 0)
retval = krb5_c_fx_cf2_simple(context,
armor_key, "clientchallengearmor",
as_key, "challengelongterm",
&challenge_key);
if (retval == 0)
retval = krb5_encrypt_helper(context, challenge_key,
KRB5_KEYUSAGE_ENC_CHALLENGE_CLIENT,
encoded_ts, &enc);
if (encoded_ts)
krb5_free_data(context, encoded_ts);
encoded_ts = NULL;
if (retval == 0) {
retval = encode_krb5_enc_data(&enc, &encoded_ts);
krb5_free_data_contents(context, &enc.ciphertext);
}
if (retval == 0) {
pa = calloc(2, sizeof(krb5_pa_data *));
if (pa == NULL)
retval = ENOMEM;
}
if (retval == 0) {
pa[0] = calloc(1, sizeof(krb5_pa_data));
if (pa[0] == NULL)
retval = ENOMEM;
}
if (retval == 0) {
pa[0]->length = encoded_ts->length;
pa[0]->contents = (unsigned char *) encoded_ts->data;
pa[0]->pa_type = KRB5_PADATA_ENCRYPTED_CHALLENGE;
encoded_ts->data = NULL;
*out_padata = pa;
pa = NULL;
}
free(pa);
krb5_free_data(context, encoded_ts);
}
if (challenge_key)
krb5_free_keyblock(context, challenge_key);
return retval;
}
static krb5_error_code
encts_process(krb5_context context, krb5_clpreauth_moddata moddata,
krb5_clpreauth_modreq modreq, krb5_get_init_creds_opt *opt,
krb5_clpreauth_callbacks cb, krb5_clpreauth_rock rock,
krb5_kdc_req *request, krb5_data *encoded_request_body,
krb5_data *encoded_previous_request, krb5_pa_data *padata,
krb5_prompter_fct prompter, void *prompter_data,
krb5_pa_data ***out_padata)
{
krb5_error_code ret;
krb5_pa_enc_ts pa_enc;
krb5_data *ts = NULL, *enc_ts = NULL;
krb5_enc_data enc_data;
krb5_pa_data **pa = NULL;
krb5_keyblock *as_key;
enc_data.ciphertext = empty_data();
ret = cb->get_as_key(context, rock, &as_key);
if (ret)
goto cleanup;
TRACE_PREAUTH_ENC_TS_KEY_GAK(context, as_key);
/*
* Try and use the timestamp of the preauth request, even if it's
* unauthenticated. We could be fooled into making a preauth response for
* a future time, but that has no security consequences other than the
* KDC's audit logs. If kdc_timesync is not configured, then this will
* just use local time.
*/
ret = cb->get_preauth_time(context, rock, TRUE, &pa_enc.patimestamp,
&pa_enc.pausec);
if (ret)
goto cleanup;
ret = encode_krb5_pa_enc_ts(&pa_enc, &ts);
if (ret)
goto cleanup;
ret = krb5_encrypt_helper(context, as_key, KRB5_KEYUSAGE_AS_REQ_PA_ENC_TS,
ts, &enc_data);
if (ret)
goto cleanup;
TRACE_PREAUTH_ENC_TS(context, pa_enc.patimestamp, pa_enc.pausec,
ts, &enc_data.ciphertext);
ret = encode_krb5_enc_data(&enc_data, &enc_ts);
if (ret)
goto cleanup;
pa = k5alloc(2 * sizeof(krb5_pa_data *), &ret);
if (pa == NULL)
goto cleanup;
pa[0] = k5alloc(sizeof(krb5_pa_data), &ret);
if (pa[0] == NULL)
goto cleanup;
pa[0]->magic = KV5M_PA_DATA;
pa[0]->pa_type = KRB5_PADATA_ENC_TIMESTAMP;
pa[0]->length = enc_ts->length;
pa[0]->contents = (krb5_octet *) enc_ts->data;
enc_ts->data = NULL;
pa[1] = NULL;
*out_padata = pa;
pa = NULL;
cleanup:
krb5_free_data(context, ts);
krb5_free_data(context, enc_ts);
free(enc_data.ciphertext.data);
free(pa);
return ret;
}
