OpenBSD-4.6/kerberosV/src/kdc/kerberos4.c
/*
* Copyright (c) 1997 - 2005 Kungliga Tekniska Högskolan
* (Royal Institute of Technology, Stockholm, Sweden).
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
*
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* 3. Neither the name of the Institute nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "kdc_locl.h"
#include <krb5-v4compat.h>
RCSID("$KTH: kerberos4.c,v 1.52 2005/04/23 20:11:55 lha Exp $");
#ifndef swap32
static u_int32_t
swap32(u_int32_t x)
{
return ((x << 24) & 0xff000000) |
((x << 8) & 0xff0000) |
((x >> 8) & 0xff00) |
((x >> 24) & 0xff);
}
#endif /* swap32 */
int
maybe_version4(unsigned char *buf, int len)
{
return len > 0 && *buf == 4;
}
static void
make_err_reply(krb5_context context, krb5_data *reply,
int code, const char *msg)
{
_krb5_krb_cr_err_reply(context, "", "", "",
kdc_time, code, msg, reply);
}
static krb5_boolean
valid_princ(krb5_context context, krb5_principal princ)
{
krb5_error_code ret;
char *s;
hdb_entry *ent;
ret = krb5_unparse_name(context, princ, &s);
if (ret)
return FALSE;
ret = db_fetch(princ, &ent);
if (ret) {
kdc_log(7, "Lookup %s failed: %s", s,
krb5_get_err_text (context, ret));
free(s);
return FALSE;
}
kdc_log(7, "Lookup %s succeeded", s);
free(s);
free_ent(ent);
return TRUE;
}
krb5_error_code
db_fetch4(const char *name, const char *instance, const char *realm,
hdb_entry **ent)
{
krb5_principal p;
krb5_error_code ret;
ret = krb5_425_conv_principal_ext(context, name, instance, realm,
valid_princ, 0, &p);
if(ret)
return ret;
ret = db_fetch(p, ent);
krb5_free_principal(context, p);
return ret;
}
#define RCHECK(X, L) if(X){make_err_reply(context, reply, KFAILURE, "Packet too short"); goto L;}
/*
* Process the v4 request in `buf, len' (received from `addr'
* (with string `from').
* Return an error code and a reply in `reply'.
*/
krb5_error_code
do_version4(unsigned char *buf,
size_t len,
krb5_data *reply,
const char *from,
struct sockaddr_in *addr)
{
krb5_storage *sp;
krb5_error_code ret;
hdb_entry *client = NULL, *server = NULL;
Key *ckey, *skey;
int8_t pvno;
int8_t msg_type;
int lsb;
char *name = NULL, *inst = NULL, *realm = NULL;
char *sname = NULL, *sinst = NULL;
int32_t req_time;
time_t max_life;
u_int8_t life;
char client_name[256];
char server_name[256];
if(!enable_v4) {
kdc_log(0, "Rejected version 4 request from %s", from);
make_err_reply(context, reply, KDC_GEN_ERR, "function not enabled");
return 0;
}
sp = krb5_storage_from_mem(buf, len);
RCHECK(krb5_ret_int8(sp, &pvno), out);
if(pvno != 4){
kdc_log(0, "Protocol version mismatch (krb4) (%d)", pvno);
make_err_reply(context, reply, KDC_PKT_VER, "protocol mismatch");
goto out;
}
RCHECK(krb5_ret_int8(sp, &msg_type), out);
lsb = msg_type & 1;
msg_type &= ~1;
switch(msg_type){
case AUTH_MSG_KDC_REQUEST: {
krb5_data ticket, cipher;
krb5_keyblock session;
krb5_data_zero(&ticket);
krb5_data_zero(&cipher);
RCHECK(krb5_ret_stringz(sp, &name), out1);
RCHECK(krb5_ret_stringz(sp, &inst), out1);
RCHECK(krb5_ret_stringz(sp, &realm), out1);
RCHECK(krb5_ret_int32(sp, &req_time), out1);
if(lsb)
req_time = swap32(req_time);
RCHECK(krb5_ret_int8(sp, &life), out1);
RCHECK(krb5_ret_stringz(sp, &sname), out1);
RCHECK(krb5_ret_stringz(sp, &sinst), out1);
snprintf (client_name, sizeof(client_name),
"%s.%s@%s", name, inst, realm);
snprintf (server_name, sizeof(server_name),
"%s.%s@%s", sname, sinst, v4_realm);
kdc_log(0, "AS-REQ (krb4) %s from %s for %s",
client_name, from, server_name);
ret = db_fetch4(name, inst, realm, &client);
if(ret) {
kdc_log(0, "Client not found in database: %s: %s",
client_name, krb5_get_err_text(context, ret));
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN,
"principal unknown");
goto out1;
}
ret = db_fetch4(sname, sinst, v4_realm, &server);
if(ret){
kdc_log(0, "Server not found in database: %s: %s",
server_name, krb5_get_err_text(context, ret));
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN,
"principal unknown");
goto out1;
}
ret = check_flags (client, client_name,
server, server_name,
TRUE);
if (ret) {
/* good error code? */
make_err_reply(context, reply, KERB_ERR_NAME_EXP,
"operation not allowed");
goto out1;
}
/*
* There's no way to do pre-authentication in v4 and thus no
* good error code to return if preauthentication is required.
*/
if (require_preauth
|| client->flags.require_preauth
|| server->flags.require_preauth) {
kdc_log(0,
"Pre-authentication required for v4-request: "
"%s for %s",
client_name, server_name);
make_err_reply(context, reply, KERB_ERR_NULL_KEY,
"preauth required");
goto out1;
}
ret = get_des_key(client, FALSE, FALSE, &ckey);
if(ret){
kdc_log(0, "no suitable DES key for client");
make_err_reply(context, reply, KDC_NULL_KEY,
"no suitable DES key for client");
goto out1;
}
#if 0
/* this is not necessary with the new code in libkrb */
/* find a properly salted key */
while(ckey->salt == NULL || ckey->salt->salt.length != 0)
ret = hdb_next_keytype2key(context, client, KEYTYPE_DES, &ckey);
if(ret){
kdc_log(0, "No version-4 salted key in database -- %s.%s@%s",
name, inst, realm);
make_err_reply(context, reply, KDC_NULL_KEY,
"No version-4 salted key in database");
goto out1;
}
#endif
ret = get_des_key(server, TRUE, FALSE, &skey);
if(ret){
kdc_log(0, "no suitable DES key for server");
/* XXX */
make_err_reply(context, reply, KDC_NULL_KEY,
"no suitable DES key for server");
goto out1;
}
max_life = _krb5_krb_life_to_time(0, life);
if(client->max_life)
max_life = min(max_life, *client->max_life);
if(server->max_life)
max_life = min(max_life, *server->max_life);
life = krb_time_to_life(kdc_time, kdc_time + max_life);
ret = krb5_generate_random_keyblock(context,
ETYPE_DES_PCBC_NONE,
&session);
if (ret) {
make_err_reply(context, reply, KFAILURE,
"Not enough random i KDC");
goto out1;
}
ret = _krb5_krb_create_ticket(context,
0,
name,
inst,
v4_realm,
addr->sin_addr.s_addr,
&session,
life,
kdc_time,
sname,
sinst,
&skey->key,
&ticket);
if (ret) {
krb5_free_keyblock_contents(context, &session);
make_err_reply(context, reply, KFAILURE,
"failed to create v4 ticket");
goto out1;
}
ret = _krb5_krb_create_ciph(context,
&session,
sname,
sinst,
v4_realm,
life,
server->kvno % 255,
&ticket,
kdc_time,
&ckey->key,
&cipher);
krb5_free_keyblock_contents(context, &session);
krb5_data_free(&ticket);
if (ret) {
make_err_reply(context, reply, KFAILURE,
"Failed to create v4 cipher");
goto out1;
}
ret = _krb5_krb_create_auth_reply(context,
name,
inst,
realm,
req_time,
0,
client->pw_end ? *client->pw_end : 0,
client->kvno % 256,
&cipher,
reply);
krb5_data_free(&cipher);
out1:
break;
}
case AUTH_MSG_APPL_REQUEST: {
struct _krb5_krb_auth_data ad;
int8_t kvno;
int8_t ticket_len;
int8_t req_len;
krb5_data auth;
int32_t address;
size_t pos;
krb5_principal tgt_princ = NULL;
hdb_entry *tgt = NULL;
Key *tkey;
time_t max_end, actual_end, issue_time;
memset(&ad, 0, sizeof(ad));
krb5_data_zero(&auth);
RCHECK(krb5_ret_int8(sp, &kvno), out2);
RCHECK(krb5_ret_stringz(sp, &realm), out2);
ret = krb5_425_conv_principal(context, "krbtgt", realm, v4_realm,
&tgt_princ);
if(ret){
kdc_log(0, "Converting krbtgt principal (krb4): %s",
krb5_get_err_text(context, ret));
make_err_reply(context, reply, KFAILURE,
"Failed to convert v4 principal (krbtgt)");
goto out2;
}
ret = db_fetch(tgt_princ, &tgt);
if(ret){
char *s;
s = kdc_log_msg(0, "Ticket-granting ticket not "
"found in database (krb4): krbtgt.%s@%s: %s",
realm, v4_realm,
krb5_get_err_text(context, ret));
make_err_reply(context, reply, KFAILURE, s);
free(s);
goto out2;
}
if(tgt->kvno % 256 != kvno){
kdc_log(0, "tgs-req (krb4) with old kvno %d (current %d) for "
"krbtgt.%s@%s", kvno, tgt->kvno % 256, realm, v4_realm);
make_err_reply(context, reply, KDC_AUTH_EXP,
"old krbtgt kvno used");
goto out2;
}
ret = get_des_key(tgt, TRUE, FALSE, &tkey);
if(ret){
kdc_log(0, "no suitable DES key for krbtgt (krb4)");
/* XXX */
make_err_reply(context, reply, KDC_NULL_KEY,
"no suitable DES key for krbtgt");
goto out2;
}
RCHECK(krb5_ret_int8(sp, &ticket_len), out2);
RCHECK(krb5_ret_int8(sp, &req_len), out2);
pos = krb5_storage_seek(sp, ticket_len + req_len, SEEK_CUR);
auth.data = buf;
auth.length = pos;
if (check_ticket_addresses)
address = addr->sin_addr.s_addr;
else
address = 0;
ret = _krb5_krb_rd_req(context, &auth, "krbtgt", realm, v4_realm,
address, &tkey->key, &ad);
if(ret){
kdc_log(0, "krb_rd_req: %d", ret);
make_err_reply(context, reply, ret, "failed to parse request");
goto out2;
}
RCHECK(krb5_ret_int32(sp, &req_time), out2);
if(lsb)
req_time = swap32(req_time);
RCHECK(krb5_ret_int8(sp, &life), out2);
RCHECK(krb5_ret_stringz(sp, &sname), out2);
RCHECK(krb5_ret_stringz(sp, &sinst), out2);
snprintf (server_name, sizeof(server_name),
"%s.%s@%s",
sname, sinst, v4_realm);
snprintf (client_name, sizeof(client_name),
"%s.%s@%s",
ad.pname, ad.pinst, ad.prealm);
kdc_log(0, "TGS-REQ (krb4) %s from %s for %s",
client_name, from, server_name);
if(strcmp(ad.prealm, realm)){
kdc_log(0, "Can't hop realms (krb4) %s -> %s", realm, ad.prealm);
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN,
"Can't hop realms");
goto out2;
}
if (!enable_v4_cross_realm && strcmp(realm, v4_realm) != 0) {
kdc_log(0, "krb4 Cross-realm %s -> %s disabled", realm, v4_realm);
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN,
"Can't hop realms");
goto out2;
}
if(strcmp(sname, "changepw") == 0){
kdc_log(0, "Bad request for changepw ticket (krb4)");
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN,
"Can't authorize password change based on TGT");
goto out2;
}
ret = db_fetch4(ad.pname, ad.pinst, ad.prealm, &client);
if(ret && ret != HDB_ERR_NOENTRY) {
char *s;
s = kdc_log_msg(0, "Client not found in database: (krb4) %s: %s",
client_name, krb5_get_err_text(context, ret));
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN, s);
free(s);
goto out2;
}
if (client == NULL && strcmp(ad.prealm, v4_realm) == 0) {
char *s;
s = kdc_log_msg(0, "Local client not found in database: (krb4) "
"%s", client_name);
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN, s);
free(s);
goto out2;
}
ret = db_fetch4(sname, sinst, v4_realm, &server);
if(ret){
char *s;
s = kdc_log_msg(0, "Server not found in database (krb4): %s: %s",
server_name, krb5_get_err_text(context, ret));
make_err_reply(context, reply, KERB_ERR_PRINCIPAL_UNKNOWN, s);
free(s);
goto out2;
}
ret = check_flags (client, client_name,
server, server_name,
FALSE);
if (ret) {
/* good error code? */
make_err_reply(context, reply, KERB_ERR_NAME_EXP,
"operation not allowed");
goto out2;
}
ret = get_des_key(server, TRUE, FALSE, &skey);
if(ret){
kdc_log(0, "no suitable DES key for server (krb4)");
/* XXX */
make_err_reply(context, reply, KDC_NULL_KEY,
"no suitable DES key for server");
goto out2;
}
max_end = _krb5_krb_life_to_time(ad.time_sec, ad.life);
max_end = min(max_end, _krb5_krb_life_to_time(kdc_time, life));
if(server->max_life)
max_end = min(max_end, kdc_time + *server->max_life);
if(client && client->max_life)
max_end = min(max_end, kdc_time + *client->max_life);
life = min(life, krb_time_to_life(kdc_time, max_end));
issue_time = kdc_time;
actual_end = _krb5_krb_life_to_time(issue_time, life);
while (actual_end > max_end && life > 1) {
/* move them into the next earlier lifetime bracket */
life--;
actual_end = _krb5_krb_life_to_time(issue_time, life);
}
if (actual_end > max_end) {
/* if life <= 1 and it's still too long, backdate the ticket */
issue_time -= actual_end - max_end;
}
{
krb5_data ticket, cipher;
krb5_keyblock session;
krb5_data_zero(&ticket);
krb5_data_zero(&cipher);
ret = krb5_generate_random_keyblock(context,
ETYPE_DES_PCBC_NONE,
&session);
if (ret) {
make_err_reply(context, reply, KFAILURE,
"Not enough random i KDC");
goto out2;
}
ret = _krb5_krb_create_ticket(context,
0,
ad.pname,
ad.pinst,
ad.prealm,
addr->sin_addr.s_addr,
&session,
life,
issue_time,
sname,
sinst,
&skey->key,
&ticket);
if (ret) {
krb5_free_keyblock_contents(context, &session);
make_err_reply(context, reply, KFAILURE,
"failed to create v4 ticket");
goto out2;
}
ret = _krb5_krb_create_ciph(context,
&session,
sname,
sinst,
v4_realm,
life,
server->kvno % 255,
&ticket,
issue_time,
&ad.session,
&cipher);
krb5_free_keyblock_contents(context, &session);
if (ret) {
make_err_reply(context, reply, KFAILURE,
"failed to create v4 cipher");
goto out2;
}
ret = _krb5_krb_create_auth_reply(context,
ad.pname,
ad.pinst,
ad.prealm,
req_time,
0,
0,
0,
&cipher,
reply);
krb5_data_free(&cipher);
}
out2:
_krb5_krb_free_auth_data(context, &ad);
if(tgt_princ)
krb5_free_principal(context, tgt_princ);
if(tgt)
free_ent(tgt);
break;
}
case AUTH_MSG_ERR_REPLY:
break;
default:
kdc_log(0, "Unknown message type (krb4): %d from %s",
msg_type, from);
make_err_reply(context, reply, KFAILURE, "Unknown message type");
}
out:
if(name)
free(name);
if(inst)
free(inst);
if(realm)
free(realm);
if(sname)
free(sname);
if(sinst)
free(sinst);
if(client)
free_ent(client);
if(server)
free_ent(server);
krb5_storage_free(sp);
return 0;
}
krb5_error_code
encode_v4_ticket(void *buf, size_t len, const EncTicketPart *et,
const PrincipalName *service, size_t *size)
{
krb5_storage *sp;
krb5_error_code ret;
char name[40], inst[40], realm[40];
char sname[40], sinst[40];
{
krb5_principal princ;
_krb5_principalname2krb5_principal(&princ,
*service,
et->crealm);
ret = krb5_524_conv_principal(context,
princ,
sname,
sinst,
realm);
krb5_free_principal(context, princ);
if(ret)
return ret;
_krb5_principalname2krb5_principal(&princ,
et->cname,
et->crealm);
ret = krb5_524_conv_principal(context,
princ,
name,
inst,
realm);
krb5_free_principal(context, princ);
}
if(ret)
return ret;
sp = krb5_storage_emem();
krb5_store_int8(sp, 0); /* flags */
krb5_store_stringz(sp, name);
krb5_store_stringz(sp, inst);
krb5_store_stringz(sp, realm);
{
unsigned char tmp[4] = { 0, 0, 0, 0 };
int i;
if(et->caddr){
for(i = 0; i < et->caddr->len; i++)
if(et->caddr->val[i].addr_type == AF_INET &&
et->caddr->val[i].address.length == 4){
memcpy(tmp, et->caddr->val[i].address.data, 4);
break;
}
}
krb5_storage_write(sp, tmp, sizeof(tmp));
}
if((et->key.keytype != ETYPE_DES_CBC_MD5 &&
et->key.keytype != ETYPE_DES_CBC_MD4 &&
et->key.keytype != ETYPE_DES_CBC_CRC) ||
et->key.keyvalue.length != 8)
return -1;
krb5_storage_write(sp, et->key.keyvalue.data, 8);
{
time_t start = et->starttime ? *et->starttime : et->authtime;
krb5_store_int8(sp, krb_time_to_life(start, et->endtime));
krb5_store_int32(sp, start);
}
krb5_store_stringz(sp, sname);
krb5_store_stringz(sp, sinst);
{
krb5_data data;
krb5_storage_to_data(sp, &data);
krb5_storage_free(sp);
*size = (data.length + 7) & ~7; /* pad to 8 bytes */
if(*size > len)
return -1;
memset((unsigned char*)buf - *size + 1, 0, *size);
memcpy((unsigned char*)buf - *size + 1, data.data, data.length);
krb5_data_free(&data);
}
return 0;
}
krb5_error_code
get_des_key(hdb_entry *principal, krb5_boolean is_server,
krb5_boolean prefer_afs_key, Key **ret_key)
{
Key *v5_key = NULL, *v4_key = NULL, *afs_key = NULL, *server_key = NULL;
int i;
krb5_enctype etypes[] = { ETYPE_DES_CBC_MD5,
ETYPE_DES_CBC_MD4,
ETYPE_DES_CBC_CRC };
for(i = 0;
i < sizeof(etypes)/sizeof(etypes[0])
&& (v5_key == NULL || v4_key == NULL ||
afs_key == NULL || server_key == NULL);
++i) {
Key *key = NULL;
while(hdb_next_enctype2key(context, principal, etypes[i], &key) == 0) {
if(key->salt == NULL) {
if(v5_key == NULL)
v5_key = key;
} else if(key->salt->type == hdb_pw_salt &&
key->salt->salt.length == 0) {
if(v4_key == NULL)
v4_key = key;
} else if(key->salt->type == hdb_afs3_salt) {
if(afs_key == NULL)
afs_key = key;
} else if(server_key == NULL)
server_key = key;
}
}
if(prefer_afs_key) {
if(afs_key)
*ret_key = afs_key;
else if(v4_key)
*ret_key = v4_key;
else if(v5_key)
*ret_key = v5_key;
else if(is_server && server_key)
*ret_key = server_key;
else
return KERB_ERR_NULL_KEY;
} else {
if(v4_key)
*ret_key = v4_key;
else if(afs_key)
*ret_key = afs_key;
else if(v5_key)
*ret_key = v5_key;
else if(is_server && server_key)
*ret_key = server_key;
else
return KERB_ERR_NULL_KEY;
}
if((*ret_key)->key.keyvalue.length == 0)
return KERB_ERR_NULL_KEY;
return 0;
}