/* Set the key for krb_rd_req so we can check tgt */
static int
set_tgtkey(char *r, krb5_kvno kvno, krb5_boolean use_3des)
{
int n;
static char lastrealm[REALM_SZ] = "";
static int last_kvno = 0;
static krb5_boolean last_use_3des = 0;
static int more;
Principal p_st;
Principal *p = &p_st;
C_Block key;
krb5_keyblock k5key;
k5key.contents = NULL;
if (!strcmp(lastrealm, r) && last_kvno == kvno && last_use_3des == use_3des)
return (KSUCCESS);
/* log("Getting key for %s", r); */
n = kerb_get_principal("krbtgt", r, p, &more, &k5key, kvno, 1, NULL);
if (n == 0)
return (KFAILURE);
if (isflagset(p->attributes, V4_KDB_DISALLOW_ALL_TIX)) {
lt = klog(L_ERR_SEXP,
"V5 DISALLOW_ALL_TIX set: \"krbtgt\" \"%s\"", r);
krb5_free_keyblock_contents(kdc_context, &k5key);
return KFAILURE;
}
if (isflagset(p->attributes, V4_KDB_DISALLOW_SVR)) {
lt = klog(L_ERR_SEXP, "V5 DISALLOW_SVR set: \"krbtgt\" \"%s\"", r);
krb5_free_keyblock_contents(kdc_context, &k5key);
return KFAILURE;
}
if (use_3des&&!K4KDC_ENCTYPE_OK(k5key.enctype)) {
krb_set_key_krb5(kdc_context, &k5key);
strncpy(lastrealm, r, sizeof(lastrealm) - 1);
lastrealm[sizeof(lastrealm) - 1] = '\0';
last_kvno = kvno;
last_use_3des = use_3des;
} else {
/* unseal tgt key from master key */
memcpy(key, &p->key_low, 4);
memcpy(((krb5_ui_4 *) key) + 1, &p->key_high, 4);
kdb_encrypt_key(key, key, master_key,
master_key_schedule, DECRYPT);
krb_set_key((char *) key, 0);
strncpy(lastrealm, r, sizeof(lastrealm) - 1);
lastrealm[sizeof(lastrealm) - 1] = '\0';
last_kvno = kvno;
}
krb5_free_keyblock_contents(kdc_context, &k5key);
return (KSUCCESS);
}
main()
{
struct sockaddr_in foreign;
int foreign_len = sizeof(foreign);
int rval, more;
static char name[] = "kpasswdd";
static struct rlimit rl = { 0, 0 };
progname = name;
openlog("kpasswdd", LOG_CONS | LOG_PID, LOG_AUTH);
signal(SIGHUP, SIG_IGN);
signal(SIGINT, SIG_IGN);
signal(SIGTSTP, SIG_IGN);
if(setrlimit(RLIMIT_CORE, &rl) < 0) {
syslog(LOG_ERR, "setrlimit: %m");
exit(1);
}
if(getpeername(0, &foreign, &foreign_len) < 0) {
syslog(LOG_ERR,"getpeername: %m");
exit(1);
}
strcpy(inst, "*");
rval = krb_recvauth(
0L, /* !MUTUAL */
0, /* file desc */
&ticket, /* client's ticket */
SERVICE, /* expected service */
inst, /* expected instance */
&foreign, /* foreign addr */
(struct sockaddr_in *) 0,
&kdata,
"",
(bit_64 *) NULL, /* key schedule */
version
);
if(rval != KSUCCESS) {
syslog(LOG_ERR, "krb_recvauth: %s", krb_err_txt[rval]);
cleanup();
exit(1);
}
/* get master key */
if(kdb_get_master_key(0, master_key, master_key_schedule) != 0) {
syslog(LOG_ERR, "couldn't get master key");
cleanup();
exit(1);
}
mkeyversion =
kdb_get_master_key(master_key, master_key_schedule, NULL);
if(mkeyversion < 0) {
syslog(LOG_NOTICE, "couldn't verify master key");
cleanup();
exit(1);
}
/* get principal info */
rval = kerb_get_principal(
kdata.pname,
kdata.pinst,
&principal_data,
1,
&more
);
if(rval != 1 || (more != 0)) {
syslog(LOG_NOTICE, "more than 1 entry for %s.%s",
kdata.pname, kdata.pinst);
cleanup();
exit(1);
}
/* get the user's key */
bcopy(&principal_data.key_low, key, 4);
bcopy(&principal_data.key_high, ((long *) key) + 1, 4);
kdb_encrypt_key(key, key, master_key, master_key_schedule,
DECRYPT);
key_sched(key, key_schedule);
des_set_key(key, key_schedule);
/* get random key and send it over {random} Kperson */
random_key(kpwd_data.random_key);
strcpy(kpwd_data.secure_msg, SECURE_STRING);
if(des_write(0, &kpwd_data, sizeof(kpwd_data)) != sizeof(kpwd_data)) {
syslog(LOG_ERR, "error writing initial data");
cleanup();
exit(1);
}
bzero(key, sizeof(key));
bzero(key_schedule, sizeof(key_schedule));
/* now read update info: { info }Krandom */
key_sched(kpwd_data.random_key, random_sched);
des_set_key(kpwd_data.random_key, random_sched);
if(des_read(0, &ud_data, sizeof(ud_data)) != sizeof(ud_data)) {
syslog(LOG_ERR, "update aborted");
cleanup();
exit(1);
}
/* validate info string by looking at the embedded string */
if(strcmp(ud_data.secure_msg, SECURE_STRING)) {
syslog(LOG_NOTICE, "invalid update from %s",
inet_ntoa(foreign.sin_addr));
cleanup();
exit(1);
}
/* produce the new key entry in the database { key }Kmaster */
string_to_key(ud_data.pw, key);
kdb_encrypt_key(key, key,
master_key, master_key_schedule,
ENCRYPT);
bcopy(key, &principal_data.key_low, 4);
bcopy(((long *) key) + 1,
&principal_data.key_high, 4);
bzero(key, sizeof(key));
principal_data.key_version++;
if(kerb_put_principal(&principal_data, 1)) {
syslog(LOG_ERR, "couldn't write new record for %s.%s",
principal_data.name, principal_data.instance);
cleanup();
exit(1);
}
syslog(LOG_NOTICE,"wrote new password field for %s.%s from %s",
principal_data.name,
principal_data.instance,
inet_ntoa(foreign.sin_addr)
);
send_ack(0, "Update complete.\n");
cleanup();
exit(0);
}
void
kerberos_v4(struct sockaddr_in *client, KTEXT pkt)
{
static KTEXT_ST rpkt_st;
KTEXT rpkt = &rpkt_st;
static KTEXT_ST ciph_st;
KTEXT ciph = &ciph_st;
static KTEXT_ST tk_st;
KTEXT tk = &tk_st;
static KTEXT_ST auth_st;
KTEXT auth = &auth_st;
AUTH_DAT ad_st;
AUTH_DAT *ad = &ad_st;
static struct in_addr client_host;
static int msg_byte_order;
static int swap_bytes;
static u_char k_flags;
/* char *p_name, *instance; */
int lifetime = 0;
int i;
C_Block key;
Key_schedule key_s;
char *ptr;
krb5_keyblock k5key;
krb5_kvno kvno;
krb5_deltat sk5life, ck5life;
KRB4_32 v4endtime, v4req_end;
k5key.contents = NULL; /* in case we have to free it */
ciph->length = 0;
client_host = client->sin_addr;
/* eval macros and correct the byte order and alignment as needed */
req_version = pkt_version(pkt); /* 1 byte, version */
req_msg_type = pkt_msg_type(pkt); /* 1 byte, Kerberos msg type */
/* set these to point to something safe */
req_name_ptr = req_inst_ptr = req_realm_ptr = "";
/* check if disabled, but we tell client */
if (kdc_v4 == KDC_V4_DISABLE) {
lt = klog(L_KRB_PERR,
"KRB will not handle v4 request from %s",
inet_ntoa(client_host));
/* send an error reply */
req_name_ptr = req_inst_ptr = req_realm_ptr = "";
kerb_err_reply(client, pkt, KERB_ERR_PKT_VER, lt);
return;
}
/* check packet version */
if (req_version != KRB_PROT_VERSION) {
lt = klog(L_KRB_PERR,
"KRB prot version mismatch: KRB =%d request = %d",
KRB_PROT_VERSION, req_version, 0);
/* send an error reply */
req_name_ptr = req_inst_ptr = req_realm_ptr = "";
kerb_err_reply(client, pkt, KERB_ERR_PKT_VER, lt);
return;
}
msg_byte_order = req_msg_type & 1;
swap_bytes = 0;
if (msg_byte_order != HOST_BYTE_ORDER) {
swap_bytes++;
}
klog(L_KRB_PINFO,
"Prot version: %d, Byte order: %d, Message type: %d",
(int) req_version, msg_byte_order, req_msg_type);
switch (req_msg_type & ~1) {
case AUTH_MSG_KDC_REQUEST:
{
int req_life; /* Requested liftime */
unsigned int request_backdate = 0; /*How far to backdate
in seconds.*/
char *service; /* Service name */
char *instance; /* Service instance */
#ifdef notdef
int kerno; /* Kerberos error number */
#endif
n_auth_req++;
tk->length = 0;
k_flags = 0; /* various kerberos flags */
/* set up and correct for byte order and alignment */
req_name_ptr = (char *) pkt_a_name(pkt);
str_length_check(req_name_ptr, ANAME_SZ);
req_inst_ptr = (char *) pkt_a_inst(pkt);
str_length_check(req_inst_ptr, INST_SZ);
req_realm_ptr = (char *) pkt_a_realm(pkt);
str_length_check(req_realm_ptr, REALM_SZ);
memcpy(&req_time_ws, pkt_time_ws(pkt), sizeof(req_time_ws));
/* time has to be diddled */
if (swap_bytes) {
swap_u_long(req_time_ws);
}
ptr = (char *) pkt_time_ws(pkt) + 4;
req_life = (*ptr++) & 0xff;
service = ptr;
str_length_check(service, SNAME_SZ);
instance = ptr + strlen(service) + 1;
str_length_check(instance, INST_SZ);
rpkt = &rpkt_st;
klog(L_INI_REQ,
"Initial ticket request Host: %s User: \"%s\" \"%s\"",
inet_ntoa(client_host), req_name_ptr, req_inst_ptr, 0);
if ((i = check_princ(req_name_ptr, req_inst_ptr, 0,
&a_name_data, &k5key, 0, &ck5life))) {
kerb_err_reply(client, pkt, i, "check_princ failed");
a_name_data.key_low = a_name_data.key_high = 0;
krb5_free_keyblock_contents(kdc_context, &k5key);
return;
}
/* don't use k5key for client */
krb5_free_keyblock_contents(kdc_context, &k5key);
tk->length = 0; /* init */
if (strcmp(service, "krbtgt"))
klog(L_NTGT_INTK,
"INITIAL request from %s.%s for %s.%s", req_name_ptr,
req_inst_ptr, service, instance, 0);
/* this does all the checking */
if ((i = check_princ(service, instance, lifetime,
&s_name_data, &k5key, 1, &sk5life))) {
kerb_err_reply(client, pkt, i, "check_princ failed");
a_name_data.key_high = a_name_data.key_low = 0;
s_name_data.key_high = s_name_data.key_low = 0;
krb5_free_keyblock_contents(kdc_context, &k5key);
return;
}
/* Bound requested lifetime with service and user */
v4req_end = krb_life_to_time(kerb_time.tv_sec, req_life);
v4req_end = min(v4req_end, kerb_time.tv_sec + ck5life);
v4req_end = min(v4req_end, kerb_time.tv_sec + sk5life);
lifetime = krb_time_to_life(kerb_time.tv_sec, v4req_end);
v4endtime = krb_life_to_time(kerb_time.tv_sec, lifetime);
/*
* Adjust issue time backwards if necessary, due to
* roundup in krb_time_to_life().
*/
if (v4endtime > v4req_end)
request_backdate = v4endtime - v4req_end;
#ifdef NOENCRYPTION
memset(session_key, 0, sizeof(C_Block));
#else
/* random session key */
des_new_random_key(session_key);
#endif
/* unseal server's key from master key */
memcpy( key, &s_name_data.key_low, 4);
memcpy( ((krb5_ui_4 *) key) + 1, &s_name_data.key_high, 4);
s_name_data.key_low = s_name_data.key_high = 0;
kdb_encrypt_key(key, key, master_key,
master_key_schedule, DECRYPT);
/* construct and seal the ticket */
/* We always issue des tickets; the 3des tickets are a broken hack*/
krb_create_ticket(tk, k_flags, a_name_data.name,
a_name_data.instance, local_realm,
client_host.s_addr, (char *) session_key,
lifetime, kerb_time.tv_sec - request_backdate,
s_name_data.name, s_name_data.instance,
key);
krb5_free_keyblock_contents(kdc_context, &k5key);
memset(key, 0, sizeof(key));
memset(key_s, 0, sizeof(key_s));
/*
* get the user's key, unseal it from the server's key, and
* use it to seal the cipher
*/
/* a_name_data.key_low a_name_data.key_high */
memcpy( key, &a_name_data.key_low, 4);
memcpy( ((krb5_ui_4 *) key) + 1, &a_name_data.key_high, 4);
a_name_data.key_low= a_name_data.key_high = 0;
/* unseal the a_name key from the master key */
kdb_encrypt_key(key, key, master_key,
master_key_schedule, DECRYPT);
create_ciph(ciph, session_key, s_name_data.name,
s_name_data.instance, local_realm, lifetime,
s_name_data.key_version, tk, kerb_time.tv_sec, key);
/* clear session key */
memset(session_key, 0, sizeof(session_key));
memset(key, 0, sizeof(key));
/* always send a reply packet */
rpkt = create_auth_reply(req_name_ptr, req_inst_ptr,
req_realm_ptr, req_time_ws, 0, a_name_data.exp_date,
a_name_data.key_version, ciph);
krb4_sendto(f, (char *) rpkt->dat, rpkt->length, 0,
(struct sockaddr *) client, sizeof (struct sockaddr_in));
memset(&a_name_data, 0, sizeof(a_name_data));
memset(&s_name_data, 0, sizeof(s_name_data));
break;
}
case AUTH_MSG_APPL_REQUEST:
{
krb5_ui_4 time_ws; /* Workstation time */
int req_life; /* Requested liftime */
char *service; /* Service name */
char *instance; /* Service instance */
int kerno = 0; /* Kerberos error number */
unsigned int request_backdate = 0; /*How far to backdate
in seconds.*/
char tktrlm[REALM_SZ];
n_appl_req++;
tk->length = 0;
k_flags = 0; /* various kerberos flags */
auth->mbz = 0; /* pkt->mbz already zeroed */
auth->length = 4 + strlen((char *)pkt->dat + 3);
if (auth->length + 1 > MAX_KTXT_LEN) {
lt = klog(L_KRB_PERR,
"APPL request with realm length too long from %s",
inet_ntoa(client_host));
kerb_err_reply(client, pkt, RD_AP_INCON,
"realm length too long");
return;
}
auth->length += (int) *(pkt->dat + auth->length) +
(int) *(pkt->dat + auth->length + 1) + 2;
if (auth->length > MAX_KTXT_LEN) {
lt = klog(L_KRB_PERR,
"APPL request with funky tkt or req_id length from %s",
inet_ntoa(client_host));
kerb_err_reply(client, pkt, RD_AP_INCON,
"funky tkt or req_id length");
return;
}
memcpy(auth->dat, pkt->dat, auth->length);
strncpy(tktrlm, (char *)auth->dat + 3, REALM_SZ);
tktrlm[REALM_SZ-1] = '\0';
kvno = (krb5_kvno)auth->dat[2];
if ((!allow_v4_crossrealm)&&strcmp(tktrlm, local_realm) != 0) {
lt = klog(L_ERR_UNK,
"Cross realm ticket from %s denied by policy,", tktrlm);
kerb_err_reply(client, pkt,
KERB_ERR_PRINCIPAL_UNKNOWN, lt);
return;
}
if (set_tgtkey(tktrlm, kvno, 0)) {
lt = klog(L_ERR_UNK,
"FAILED set_tgtkey realm %s, kvno %d. Host: %s ",
tktrlm, kvno, inet_ntoa(client_host));
/* no better error code */
kerb_err_reply(client, pkt,
KERB_ERR_PRINCIPAL_UNKNOWN, lt);
return;
}
kerno = krb_rd_req(auth, "krbtgt", tktrlm, client_host.s_addr,
ad, 0);
if (kerno) {
if (set_tgtkey(tktrlm, kvno, 1)) {
lt = klog(L_ERR_UNK,
"FAILED 3des set_tgtkey realm %s, kvno %d. Host: %s ",
tktrlm, kvno, inet_ntoa(client_host));
/* no better error code */
kerb_err_reply(client, pkt,
KERB_ERR_PRINCIPAL_UNKNOWN, lt);
return;
}
kerno = krb_rd_req(auth, "krbtgt", tktrlm, client_host.s_addr,
ad, 0);
}
if (kerno) {
klog(L_ERR_UNK, "FAILED krb_rd_req from %s: %s",
inet_ntoa(client_host), krb_get_err_text(kerno));
req_name_ptr = req_inst_ptr = req_realm_ptr = "";
kerb_err_reply(client, pkt, kerno, "krb_rd_req failed");
return;
}
ptr = (char *) pkt->dat + auth->length;
memcpy(&time_ws, ptr, 4);
ptr += 4;
req_life = (*ptr++) & 0xff;
service = ptr;
str_length_check(service, SNAME_SZ);
instance = ptr + strlen(service) + 1;
str_length_check(instance, INST_SZ);
klog(L_APPL_REQ, "APPL Request %s.%s@%s on %s for %s.%s",
ad->pname, ad->pinst, ad->prealm,
inet_ntoa(client_host), service, instance, 0);
req_name_ptr = ad->pname;
req_inst_ptr = ad->pinst;
req_realm_ptr = ad->prealm;
if (strcmp(ad->prealm, tktrlm)) {
kerb_err_reply(client, pkt, KERB_ERR_PRINCIPAL_UNKNOWN,
"Can't hop realms");
return;
}
if (!strcmp(service, "changepw")) {
kerb_err_reply(client, pkt, KERB_ERR_PRINCIPAL_UNKNOWN,
"Can't authorize password changed based on TGT");
return;
}
kerno = check_princ(service, instance, req_life,
&s_name_data, &k5key, 1, &sk5life);
if (kerno) {
kerb_err_reply(client, pkt, kerno, "check_princ failed");
s_name_data.key_high = s_name_data.key_low = 0;
krb5_free_keyblock_contents(kdc_context, &k5key);
return;
}
/* Bound requested lifetime with service and user */
v4endtime = krb_life_to_time((KRB4_32)ad->time_sec, ad->life);
v4req_end = krb_life_to_time(kerb_time.tv_sec, req_life);
v4req_end = min(v4endtime, v4req_end);
v4req_end = min(v4req_end, kerb_time.tv_sec + sk5life);
lifetime = krb_time_to_life(kerb_time.tv_sec, v4req_end);
v4endtime = krb_life_to_time(kerb_time.tv_sec, lifetime);
/*
* Adjust issue time backwards if necessary, due to
* roundup in krb_time_to_life().
*/
if (v4endtime > v4req_end)
request_backdate = v4endtime - v4req_end;
/* unseal server's key from master key */
memcpy(key, &s_name_data.key_low, 4);
memcpy(((krb5_ui_4 *) key) + 1, &s_name_data.key_high, 4);
s_name_data.key_low = s_name_data.key_high = 0;
kdb_encrypt_key(key, key, master_key,
master_key_schedule, DECRYPT);
/* construct and seal the ticket */
#ifdef NOENCRYPTION
memset(session_key, 0, sizeof(C_Block));
#else
/* random session key */
des_new_random_key(session_key);
#endif
/* ALways issue des tickets*/
krb_create_ticket(tk, k_flags, ad->pname, ad->pinst,
ad->prealm, client_host.s_addr,
(char *) session_key, lifetime,
kerb_time.tv_sec - request_backdate,
s_name_data.name, s_name_data.instance,
key);
krb5_free_keyblock_contents(kdc_context, &k5key);
memset(key, 0, sizeof(key));
memset(key_s, 0, sizeof(key_s));
create_ciph(ciph, session_key, service, instance,
local_realm,
lifetime, s_name_data.key_version, tk,
kerb_time.tv_sec, ad->session);
/* clear session key */
memset(session_key, 0, sizeof(session_key));
memset(ad->session, 0, sizeof(ad->session));
rpkt = create_auth_reply(ad->pname, ad->pinst,
ad->prealm, time_ws,
0, 0, 0, ciph);
krb4_sendto(f, (char *) rpkt->dat, rpkt->length, 0,
(struct sockaddr *) client, sizeof (struct sockaddr_in));
memset(&s_name_data, 0, sizeof(s_name_data));
break;
}
#ifdef notdef_DIE
case AUTH_MSG_DIE:
{
lt = klog(L_DEATH_REQ,
"Host: %s User: \"%s\" \"%s\" Kerberos killed",
inet_ntoa(client_host), req_name_ptr, req_inst_ptr, 0);
exit(0);
}
#endif /* notdef_DIE */
default:
{
lt = klog(L_KRB_PERR,
"Unknown message type: %d from %s port %u",
req_msg_type, inet_ntoa(client_host),
ntohs(client->sin_port));
break;
}
}
}