krb5_error_code
krb5int_fast_tgs_armor(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_keyblock *subkey, krb5_keyblock *session_key,
krb5_ccache ccache, krb5_data *target_realm)
{
krb5_principal target_principal = NULL;
krb5_keyblock *existing_armor = NULL;
krb5_error_code retval = 0;
if (ccache) {
retval = krb5int_tgtname(context, target_realm, target_realm,
&target_principal);
if (retval == 0)
retval = fast_armor_ap_request(context, state, ccache,
target_principal);
if (retval == 0) {
existing_armor = state->armor_key;
state->armor_key = NULL;
retval = krb5_c_fx_cf2_simple(context, existing_armor,
"explicitarmor", subkey,
"tgsarmor", &state->armor_key);
}
} else {
retval = krb5_c_fx_cf2_simple(context, subkey, "subkeyarmor",
session_key, "ticketarmor",
&state->armor_key);
}
if (target_principal)
krb5_free_principal(context, target_principal);
krb5_free_keyblock(context, existing_armor);
return retval;
}
static krb5_error_code
return_pkinit_kx(krb5_context context, krb5_kdc_req *request,
krb5_kdc_rep *reply, krb5_keyblock *encrypting_key,
krb5_pa_data **out_padata)
{
krb5_error_code ret = 0;
krb5_keyblock *session = reply->ticket->enc_part2->session;
krb5_keyblock *new_session = NULL;
krb5_pa_data *pa = NULL;
krb5_enc_data enc;
krb5_data *scratch = NULL;
*out_padata = NULL;
enc.ciphertext.data = NULL;
if (!krb5_principal_compare(context, request->client,
krb5_anonymous_principal()))
return 0;
/*
* The KDC contribution key needs to be a fresh key of an enctype supported
* by the client and server. The existing session key meets these
* requirements so we use it.
*/
ret = krb5_c_fx_cf2_simple(context, session, "PKINIT",
encrypting_key, "KEYEXCHANGE",
&new_session);
if (ret)
goto cleanup;
ret = encode_krb5_encryption_key( session, &scratch);
if (ret)
goto cleanup;
ret = krb5_encrypt_helper(context, encrypting_key,
KRB5_KEYUSAGE_PA_PKINIT_KX, scratch, &enc);
if (ret)
goto cleanup;
memset(scratch->data, 0, scratch->length);
krb5_free_data(context, scratch);
scratch = NULL;
ret = encode_krb5_enc_data(&enc, &scratch);
if (ret)
goto cleanup;
pa = malloc(sizeof(krb5_pa_data));
if (pa == NULL) {
ret = ENOMEM;
goto cleanup;
}
pa->pa_type = KRB5_PADATA_PKINIT_KX;
pa->length = scratch->length;
pa->contents = (krb5_octet *) scratch->data;
*out_padata = pa;
scratch->data = NULL;
memset(session->contents, 0, session->length);
krb5_free_keyblock_contents(context, session);
*session = *new_session;
new_session->contents = NULL;
cleanup:
krb5_free_data_contents(context, &enc.ciphertext);
krb5_free_keyblock(context, new_session);
krb5_free_data(context, scratch);
return ret;
}
static krb5_error_code
fast_armor_ap_request(krb5_context context,
struct krb5int_fast_request_state *state,
krb5_ccache ccache, krb5_principal target_principal)
{
krb5_error_code retval = 0;
krb5_creds creds, *out_creds = NULL;
krb5_auth_context authcontext = NULL;
krb5_data encoded_authenticator;
krb5_fast_armor *armor = NULL;
krb5_keyblock *subkey = NULL, *armor_key = NULL;
encoded_authenticator.data = NULL;
memset(&creds, 0, sizeof(creds));
creds.server = target_principal;
retval = krb5_cc_get_principal(context, ccache, &creds.client);
if (retval == 0)
retval = krb5_get_credentials(context, 0, ccache, &creds, &out_creds);
if (retval == 0) {
TRACE_FAST_ARMOR_CCACHE_KEY(context, &out_creds->keyblock);
retval = krb5_mk_req_extended(context, &authcontext,
AP_OPTS_USE_SUBKEY, NULL /*data*/,
out_creds, &encoded_authenticator);
}
if (retval == 0)
retval = krb5_auth_con_getsendsubkey(context, authcontext, &subkey);
if (retval == 0)
retval = krb5_c_fx_cf2_simple(context, subkey, "subkeyarmor",
&out_creds->keyblock, "ticketarmor",
&armor_key);
if (retval == 0) {
TRACE_FAST_ARMOR_KEY(context, armor_key);
armor = calloc(1, sizeof(krb5_fast_armor));
if (armor == NULL)
retval = ENOMEM;
}
if (retval == 0) {
armor->armor_type = KRB5_FAST_ARMOR_AP_REQUEST;
armor->armor_value = encoded_authenticator;
encoded_authenticator.data = NULL;
encoded_authenticator.length = 0;
state->armor = armor;
armor = NULL;
state->armor_key = armor_key;
armor_key = NULL;
}
krb5_free_keyblock(context, armor_key);
krb5_free_keyblock(context, subkey);
if (out_creds)
krb5_free_creds(context, out_creds);
/* target_principal is owned by caller. */
creds.server = NULL;
krb5_free_cred_contents(context, &creds);
if (encoded_authenticator.data)
krb5_free_data_contents(context, &encoded_authenticator);
krb5_auth_con_free(context, authcontext);
return retval;
}
static krb5_error_code armor_ap_request
(struct kdc_request_state *state, krb5_fast_armor *armor)
{
krb5_error_code retval = 0;
krb5_auth_context authcontext = NULL;
krb5_ticket *ticket = NULL;
krb5_keyblock *subkey = NULL;
kdc_realm_t *kdc_active_realm = state->realm_data;
assert(armor->armor_type == KRB5_FAST_ARMOR_AP_REQUEST);
krb5_clear_error_message(kdc_context);
retval = krb5_auth_con_init(kdc_context, &authcontext);
if (retval == 0)
retval = krb5_auth_con_setflags(kdc_context,
authcontext, 0); /*disable replay cache*/
retval = krb5_rd_req(kdc_context, &authcontext,
&armor->armor_value, NULL /*server*/,
kdc_active_realm->realm_keytab, NULL, &ticket);
if (retval != 0) {
const char * errmsg = krb5_get_error_message(kdc_context, retval);
krb5_set_error_message(kdc_context, retval,
_("%s while handling ap-request armor"),
errmsg);
krb5_free_error_message(kdc_context, errmsg);
}
if (retval == 0) {
if (!krb5_principal_compare_any_realm(kdc_context,
tgs_server,
ticket->server)) {
krb5_set_error_message(kdc_context, KRB5KDC_ERR_SERVER_NOMATCH,
_("ap-request armor for something other "
"than the local TGS"));
retval = KRB5KDC_ERR_SERVER_NOMATCH;
}
}
if (retval == 0) {
retval = krb5_auth_con_getrecvsubkey(kdc_context, authcontext, &subkey);
if (retval != 0 || subkey == NULL) {
krb5_set_error_message(kdc_context, KRB5KDC_ERR_POLICY,
_("ap-request armor without subkey"));
retval = KRB5KDC_ERR_POLICY;
}
}
if (retval == 0)
retval = krb5_c_fx_cf2_simple(kdc_context,
subkey, "subkeyarmor",
ticket->enc_part2->session, "ticketarmor",
&state->armor_key);
if (ticket)
krb5_free_ticket(kdc_context, ticket);
if (subkey)
krb5_free_keyblock(kdc_context, subkey);
if (authcontext)
krb5_auth_con_free(kdc_context, authcontext);
return retval;
}
krb5_error_code
kdc_fast_handle_reply_key(struct kdc_request_state *state,
krb5_keyblock *existing_key,
krb5_keyblock **out_key)
{
krb5_error_code retval = 0;
kdc_realm_t *kdc_active_realm = state->realm_data;
if (state->armor_key)
retval = krb5_c_fx_cf2_simple(kdc_context,
state->strengthen_key, "strengthenkey",
existing_key,
"replykey", out_key);
else
retval = krb5_copy_keyblock(kdc_context, existing_key, out_key);
return retval;
}
krb5_error_code krb5int_fast_reply_key(krb5_context context,
krb5_keyblock *strengthen_key,
krb5_keyblock *existing_key,
krb5_keyblock *out_key)
{
krb5_keyblock *key = NULL;
krb5_error_code retval = 0;
krb5_free_keyblock_contents(context, out_key);
if (strengthen_key) {
retval = krb5_c_fx_cf2_simple(context, strengthen_key,
"strengthenkey", existing_key, "replykey", &key);
if (retval == 0) {
*out_key = *key;
free(key);
}
} else {
retval = krb5_copy_keyblock_contents(context, existing_key, out_key);
}
return retval;
}
static krb5_error_code
process_preauth(krb5_context context, void *plugin_context,
void *request_context, krb5_get_init_creds_opt *opt,
preauth_get_client_data_proc get_data_proc,
struct _krb5_preauth_client_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,
preauth_get_as_key_proc gak_fct, void *gak_data,
krb5_data *salt, krb5_data *s2kparams, krb5_keyblock *as_key,
krb5_pa_data ***out_padata)
{
krb5_error_code retval = 0;
krb5_enctype enctype = 0;
krb5_keyblock *challenge_key = NULL, *armor_key = NULL;
krb5_data *etype_data = NULL;
krb5int_access kaccess;
if (krb5int_accessor(&kaccess, KRB5INT_ACCESS_VERSION) != 0)
return 0;
retval = fast_get_armor_key(context, get_data_proc, rock, &armor_key);
if (retval || armor_key == NULL)
return 0;
retval = get_data_proc(context, rock, krb5plugin_preauth_client_get_etype, &etype_data);
if (retval == 0) {
enctype = *((krb5_enctype *)etype_data->data);
if (as_key->length == 0 ||as_key->enctype != enctype)
retval = gak_fct(context, request->client,
enctype, prompter, prompter_data,
salt, s2kparams,
as_key, gak_data);
}
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 =kaccess.decode_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 (retval == 0)
fast_set_kdc_verified(context, get_data_proc, rock);
if (enc)
kaccess.free_enc_data(context, enc);
} else if (retval == 0) { /*No padata; we send*/
krb5_enc_data enc;
krb5_pa_data *pa = NULL;
krb5_pa_data **pa_array = NULL;
krb5_data *encoded_ts = NULL;
krb5_pa_enc_ts ts;
enc.ciphertext.data = NULL;
retval = krb5_us_timeofday(context, &ts.patimestamp, &ts.pausec);
if (retval == 0)
retval = kaccess.encode_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 = kaccess.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 = kaccess.encode_enc_data(&enc, &encoded_ts);
krb5_free_data_contents(context, &enc.ciphertext);
}
if (retval == 0) {
pa = calloc(1, sizeof(krb5_pa_data));
if (pa == NULL)
retval = ENOMEM;
}
if (retval == 0) {
pa_array = calloc(2, sizeof(krb5_pa_data *));
if (pa_array == NULL)
retval = ENOMEM;
}
if (retval == 0) {
pa->length = encoded_ts->length;
pa->contents = (unsigned char *) encoded_ts->data;
pa->pa_type = KRB5_PADATA_ENCRYPTED_CHALLENGE;
free(encoded_ts);
encoded_ts = NULL;
pa_array[0] = pa;
pa = NULL;
*out_padata = pa_array;
pa_array = NULL;
}
if (pa)
free(pa);
if (encoded_ts)
krb5_free_data(context, encoded_ts);
if (pa_array)
free(pa_array);
}
if (challenge_key)
krb5_free_keyblock(context, challenge_key);
if (armor_key)
krb5_free_keyblock(context, armor_key);
if (etype_data != NULL)
get_data_proc(context, rock, krb5plugin_preauth_client_free_etype,
&etype_data);
return retval;
}
static krb5_error_code
kdc_verify_preauth(krb5_context context, struct _krb5_db_entry_new *client,
krb5_data *req_pkt, krb5_kdc_req *request,
krb5_enc_tkt_part *enc_tkt_reply, krb5_pa_data *data,
preauth_get_entry_data_proc get_entry_proc,
void *pa_module_context, void **pa_request_context,
krb5_data **e_data, krb5_authdata ***authz_data)
{
krb5_error_code retval = 0;
krb5_timestamp now;
krb5_enc_data *enc = NULL;
krb5_data scratch, plain;
krb5_keyblock *armor_key = NULL;
krb5_pa_enc_ts *ts = NULL;
krb5int_access kaccess;
krb5_keyblock *client_keys = NULL;
krb5_data *client_data = NULL;
krb5_keyblock *challenge_key = NULL;
int i = 0;
plain.data = NULL;
if (krb5int_accessor(&kaccess, KRB5INT_ACCESS_VERSION) != 0)
return 0;
retval = fast_kdc_get_armor_key(context, get_entry_proc, request, client, &armor_key);
if (retval == 0 &&armor_key == NULL) {
retval = ENOENT;
krb5_set_error_message(context, ENOENT, "Encrypted Challenge used outside of FAST tunnel");
}
scratch.data = (char *) data->contents;
scratch.length = data->length;
if (retval == 0)
retval = kaccess.decode_enc_data(&scratch, &enc);
if (retval == 0) {
plain.data = malloc(enc->ciphertext.length);
plain.length = enc->ciphertext.length;
if (plain.data == NULL)
retval = ENOMEM;
}
if (retval == 0)
retval = get_entry_proc(context, request, client,
krb5plugin_preauth_keys, &client_data);
if (retval == 0) {
client_keys = (krb5_keyblock *) client_data->data;
for (i = 0; client_keys[i].enctype&& (retval == 0); i++ ) {
retval = krb5_c_fx_cf2_simple(context,
armor_key, "clientchallengearmor",
&client_keys[i], "challengelongterm",
&challenge_key);
if (retval == 0)
retval = krb5_c_decrypt(context, challenge_key,
KRB5_KEYUSAGE_ENC_CHALLENGE_CLIENT,
NULL, enc, &plain);
if (challenge_key)
krb5_free_keyblock(context, challenge_key);
challenge_key = NULL;
if (retval == 0)
break;
/*We failed to decrypt. Try next key*/
retval = 0;
krb5_free_keyblock_contents(context, &client_keys[i]);
}
if (client_keys[i].enctype == 0) {
retval = KRB5KDC_ERR_PREAUTH_FAILED;
krb5_set_error_message(context, retval, "Incorrect password in encrypted challenge");
} else { /*not run out of keys*/
int j;
assert (retval == 0);
for (j = i+1; client_keys[j].enctype; j++)
krb5_free_keyblock_contents(context, &client_keys[j]);
}
}
if (retval == 0)
retval = kaccess.decode_enc_ts(&plain, &ts);
if (retval == 0)
retval = krb5_timeofday(context, &now);
if (retval == 0) {
if (labs(now-ts->patimestamp) < context->clockskew) {
enc_tkt_reply->flags |= TKT_FLG_PRE_AUTH;
/*
* If this fails, we won't generate a reply to the client. That
* may cause the client to fail, but at this point the KDC has
* considered this a success, so the return value is ignored.
*/
fast_kdc_replace_reply_key(context, get_entry_proc, request);
krb5_c_fx_cf2_simple(context, armor_key, "kdcchallengearmor",
&client_keys[i], "challengelongterm",
(krb5_keyblock **) pa_request_context);
} else { /*skew*/
retval = KRB5KRB_AP_ERR_SKEW;
}
}
if (client_keys) {
if (client_keys[i].enctype)
krb5_free_keyblock_contents(context, &client_keys[i]);
krb5_free_data(context, client_data);
}
if (armor_key)
krb5_free_keyblock(context, armor_key);
if (plain.data)
free(plain.data);
if (enc)
kaccess.free_enc_data(context, enc);
if (ts)
kaccess.free_enc_ts(context, ts);
return retval;
}
krb5_error_code
kdc_find_fast(krb5_kdc_req **requestptr,
krb5_data *checksummed_data,
krb5_keyblock *tgs_subkey,
krb5_keyblock *tgs_session,
struct kdc_request_state *state,
krb5_data **inner_body_out)
{
krb5_error_code retval = 0;
krb5_pa_data *fast_padata, *cookie_padata = NULL;
krb5_data scratch, *inner_body = NULL;
krb5_fast_req * fast_req = NULL;
krb5_kdc_req *request = *requestptr;
krb5_fast_armored_req *fast_armored_req = NULL;
krb5_checksum *cksum;
krb5_boolean cksum_valid;
krb5_keyblock empty_keyblock;
kdc_realm_t *kdc_active_realm = state->realm_data;
if (inner_body_out != NULL)
*inner_body_out = NULL;
scratch.data = NULL;
krb5_clear_error_message(kdc_context);
memset(&empty_keyblock, 0, sizeof(krb5_keyblock));
fast_padata = krb5int_find_pa_data(kdc_context,
request->padata, KRB5_PADATA_FX_FAST);
if (fast_padata != NULL){
scratch.length = fast_padata->length;
scratch.data = (char *) fast_padata->contents;
retval = decode_krb5_pa_fx_fast_request(&scratch, &fast_armored_req);
if (retval == 0 &&fast_armored_req->armor) {
switch (fast_armored_req->armor->armor_type) {
case KRB5_FAST_ARMOR_AP_REQUEST:
if (tgs_subkey) {
retval = KRB5KDC_ERR_PREAUTH_FAILED;
krb5_set_error_message(kdc_context, retval,
_("Ap-request armor not permitted "
"with TGS"));
break;
}
retval = armor_ap_request(state, fast_armored_req->armor);
break;
default:
krb5_set_error_message(kdc_context, KRB5KDC_ERR_PREAUTH_FAILED,
_("Unknown FAST armor type %d"),
fast_armored_req->armor->armor_type);
retval = KRB5KDC_ERR_PREAUTH_FAILED;
}
}
if (retval == 0 && !state->armor_key) {
if (tgs_subkey)
retval = krb5_c_fx_cf2_simple(kdc_context,
tgs_subkey, "subkeyarmor",
tgs_session, "ticketarmor",
&state->armor_key);
else {
retval = KRB5KDC_ERR_PREAUTH_FAILED;
krb5_set_error_message(kdc_context, retval,
_("No armor key but FAST armored "
"request present"));
}
}
if (retval == 0) {
krb5_data plaintext;
plaintext.length = fast_armored_req->enc_part.ciphertext.length;
plaintext.data = malloc(plaintext.length);
if (plaintext.data == NULL)
retval = ENOMEM;
retval = krb5_c_decrypt(kdc_context,
state->armor_key,
KRB5_KEYUSAGE_FAST_ENC, NULL,
&fast_armored_req->enc_part,
&plaintext);
if (retval == 0)
retval = decode_krb5_fast_req(&plaintext, &fast_req);
if (retval == 0 && inner_body_out != NULL) {
retval = fetch_asn1_field((unsigned char *)plaintext.data,
1, 2, &scratch);
if (retval == 0) {
retval = krb5_copy_data(kdc_context, &scratch,
&inner_body);
}
}
if (plaintext.data)
free(plaintext.data);
}
cksum = &fast_armored_req->req_checksum;
if (retval == 0)
retval = krb5_c_verify_checksum(kdc_context, state->armor_key,
KRB5_KEYUSAGE_FAST_REQ_CHKSUM,
checksummed_data, cksum,
&cksum_valid);
if (retval == 0 && !cksum_valid) {
retval = KRB5KRB_AP_ERR_MODIFIED;
krb5_set_error_message(kdc_context, retval,
_("FAST req_checksum invalid; request "
"modified"));
}
if (retval == 0) {
if (!krb5_c_is_keyed_cksum(cksum->checksum_type)) {
retval = KRB5KDC_ERR_POLICY;
krb5_set_error_message(kdc_context, retval,
_("Unkeyed checksum used in fast_req"));
}
}
if (retval == 0) {
if ((fast_req->fast_options & UNSUPPORTED_CRITICAL_FAST_OPTIONS) != 0)
retval = KRB5KDC_ERR_UNKNOWN_CRITICAL_FAST_OPTION;
}
if (retval == 0)
cookie_padata = krb5int_find_pa_data(kdc_context,
fast_req->req_body->padata,
KRB5_PADATA_FX_COOKIE);
if (retval == 0) {
state->fast_options = fast_req->fast_options;
krb5_free_kdc_req( kdc_context, request);
*requestptr = fast_req->req_body;
fast_req->req_body = NULL;
}
}
else {
cookie_padata = krb5int_find_pa_data(kdc_context,
request->padata,
KRB5_PADATA_FX_COOKIE);
}
if (retval == 0 && cookie_padata != NULL) {
krb5_pa_data *new_padata = malloc(sizeof (krb5_pa_data));
if (new_padata == NULL) {
retval = ENOMEM;
} else {
new_padata->pa_type = KRB5_PADATA_FX_COOKIE;
new_padata->length = cookie_padata->length;
new_padata->contents = malloc(new_padata->length);
if (new_padata->contents == NULL) {
retval = ENOMEM;
free(new_padata);
} else {
memcpy(new_padata->contents, cookie_padata->contents,
new_padata->length);
state->cookie = new_padata;
}
}
}
if (retval == 0 && inner_body_out != NULL) {
*inner_body_out = inner_body;
inner_body = NULL;
}
krb5_free_data(kdc_context, inner_body);
if (fast_req)
krb5_free_fast_req( kdc_context, fast_req);
if (fast_armored_req)
krb5_free_fast_armored_req(kdc_context, fast_armored_req);
return retval;
}
static void
ec_verify(krb5_context context, krb5_data *req_pkt, krb5_kdc_req *request,
krb5_enc_tkt_part *enc_tkt_reply, krb5_pa_data *data,
krb5_kdcpreauth_callbacks cb, krb5_kdcpreauth_rock rock,
krb5_kdcpreauth_moddata moddata,
krb5_kdcpreauth_verify_respond_fn respond, void *arg)
{
krb5_error_code retval = 0;
krb5_timestamp now;
krb5_enc_data *enc = NULL;
krb5_data scratch, plain;
krb5_keyblock *armor_key = cb->fast_armor(context, rock);
krb5_pa_enc_ts *ts = NULL;
krb5_keyblock *client_keys = NULL;
krb5_keyblock *challenge_key = NULL;
krb5_keyblock *kdc_challenge_key;
krb5_kdcpreauth_modreq modreq = NULL;
int i = 0;
plain.data = NULL;
if (armor_key == NULL) {
retval = ENOENT;
krb5_set_error_message(context, ENOENT,
_("Encrypted Challenge used outside of FAST "
"tunnel"));
}
scratch.data = (char *) data->contents;
scratch.length = data->length;
if (retval == 0)
retval = decode_krb5_enc_data(&scratch, &enc);
if (retval == 0) {
plain.data = malloc(enc->ciphertext.length);
plain.length = enc->ciphertext.length;
if (plain.data == NULL)
retval = ENOMEM;
}
if (retval == 0)
retval = cb->client_keys(context, rock, &client_keys);
if (retval == 0) {
for (i = 0; client_keys[i].enctype&& (retval == 0); i++ ) {
retval = krb5_c_fx_cf2_simple(context,
armor_key, "clientchallengearmor",
&client_keys[i], "challengelongterm",
&challenge_key);
if (retval == 0)
retval = krb5_c_decrypt(context, challenge_key,
KRB5_KEYUSAGE_ENC_CHALLENGE_CLIENT,
NULL, enc, &plain);
if (challenge_key)
krb5_free_keyblock(context, challenge_key);
challenge_key = NULL;
if (retval == 0)
break;
/*We failed to decrypt. Try next key*/
retval = 0;
}
if (client_keys[i].enctype == 0) {
retval = KRB5KDC_ERR_PREAUTH_FAILED;
krb5_set_error_message(context, retval,
_("Incorrect password in encrypted "
"challenge"));
}
}
if (retval == 0)
retval = decode_krb5_pa_enc_ts(&plain, &ts);
if (retval == 0)
retval = krb5_timeofday(context, &now);
if (retval == 0) {
if (labs(now-ts->patimestamp) < context->clockskew) {
enc_tkt_reply->flags |= TKT_FLG_PRE_AUTH;
/*
* If this fails, we won't generate a reply to the client. That
* may cause the client to fail, but at this point the KDC has
* considered this a success, so the return value is ignored.
*/
if (krb5_c_fx_cf2_simple(context, armor_key, "kdcchallengearmor",
&client_keys[i], "challengelongterm",
&kdc_challenge_key) == 0)
modreq = (krb5_kdcpreauth_modreq)kdc_challenge_key;
} else { /*skew*/
retval = KRB5KRB_AP_ERR_SKEW;
}
}
cb->free_keys(context, rock, client_keys);
if (plain.data)
free(plain.data);
if (enc)
krb5_free_enc_data(context, enc);
if (ts)
krb5_free_pa_enc_ts(context, ts);
(*respond)(arg, retval, modreq, NULL, NULL);
}
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;
}
