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233876ab730bb43176eb3f7d62fd9366e8c99e8c
heimdal/kdc/kerberos5.c
Assar Westerlund 233876ab73 MIN 
git-svn-id: svn://svn.h5l.se/heimdal/trunk/heimdal@1442 ec53bebd-3082-4978-b11e-865c3cabbd6b
1997-03-16 17:18:39 +00:00

546 lines
14 KiB
C
Raw Blame History

#include "kdc_locl.h"
#define MIN(x,y) (((x)<(y))?(x):(y))
RCSID("$Id$");
struct timeval now;
#define kdc_time now.tv_sec
#ifndef MIN
#define MIN(A,B) ((A)<(B)?(A):(B))
#endif
hdb_entry*
db_fetch(krb5_context context, PrincipalName *principal, char *realm)
{
HDB *db;
hdb_entry *ent;
ent = malloc(sizeof(*ent));
principalname2krb5_principal(&ent->principal, *principal, realm);
hdb_open(context, &db, NULL, O_RDONLY, 0);
db->fetch(context, db, ent);
db->close(context, db);
return ent;
}
krb5_error_code
krb5_encrypt (krb5_context context,
void *ptr,
size_t len,
krb5_keyblock *keyblock,
krb5_data *result);
krb5_mk_error(krb5_principal princ,
krb5_error_code error_code,
krb5_data *err)
{
KRB_ERROR msg;
unsigned char buf[1024];
memset(&msg, 0, sizeof(msg));
msg.pvno = 5;
msg.msg_type = krb_error;
msg.stime = time(0);
msg.error_code = error_code;
msg.realm = princ->realm.data;
krb5_principal2principalname(&msg.sname, princ);
err->length = encode_KRB_ERROR(buf + sizeof(buf) - 1, sizeof(buf), &msg);
err->data = malloc(err->length);
memcpy(err->data, buf + sizeof(buf) - err->length, err->length);
return 0;
}
krb5_error_code
mk_des_keyblock(EncryptionKey *kb)
{
kb->keytype = KEYTYPE_DES;
kb->keyvalue.data = malloc(sizeof(des_cblock));
kb->keyvalue.length = sizeof(des_cblock);
des_rand_data_key(kb->keyvalue.data);
return 0;
}
krb5_error_code
as_rep(krb5_context context,
KDC_REQ *req,
KDC_REP *rep,
krb5_data *data)
{
KDCOptions f = req->req_body.kdc_options;
KDC_REQ_BODY *b = &req->req_body;
hdb_entry *client, *server;
int use_etype;
EncTicketPart *et = calloc(1, sizeof(*et));
EncKDCRepPart *ek = calloc(1, sizeof(*ek));
client = db_fetch(context, b->cname, b->realm);
server = db_fetch(context, b->sname, b->realm);
if(client == NULL)
return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
if(server == NULL)
return KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
/* XXX Check for pa_enc_timestamp */
if(b->etype.len == 0)
return KRB5KDC_ERR_ETYPE_NOSUPP; /* XXX */
use_etype = b->etype.val[0];
memset(rep, 0, sizeof(*rep));
rep->pvno = 5;
rep->msg_type = krb_as_rep;
rep->crealm = b->realm;
rep->cname = *b->cname;
rep->ticket.tkt_vno = 5;
rep->ticket.sname = *b->sname;
rep->ticket.realm = b->realm;
if(f.renew || f.validate || f.proxy || f.forwarded || f.enc_tkt_in_skey)
return KRB5KDC_ERR_BADOPTION;
et->flags.initial = 1;
et->flags.forwardable = f.forwardable;
et->flags.proxiable = f.proxiable;
et->flags.may_postdate = f.allow_postdate;
mk_des_keyblock(&et->key);
et->cname = *b->cname;
et->crealm = b->realm;
{
time_t start;
time_t t;
start = et->authtime = kdc_time;
if(f.postdated && req->req_body.from){
et->starttime = malloc(sizeof(*et->starttime));
start = *et->starttime = *req->req_body.from;
et->flags.invalid = 1;
et->flags.postdated = 1; /* XXX ??? */
}
t = b->till;
if(b->till == 0)
t = start + client->max_life;
t = MIN(t, start + client->max_life);
t = MIN(t, start + server->max_life);
#if 0
t = MIN(t, start + realm->max_life);
#endif
et->endtime = t;
if(f.renewable_ok && et->endtime < b->till){
f.renewable = 1;
if(b->rtime == NULL){
b->rtime = malloc(sizeof(*b->rtime));
*b->rtime = 0;
}
if(*b->rtime < b->till)
*b->rtime = b->till;
}
if(f.renewable && b->rtime){
t = *b->rtime;
if(t == 0)
t = start + client->max_renew;
t = MIN(t, start + client->max_renew);
t = MIN(t, start + server->max_renew);
#if 0
t = MIN(t, start + realm->max_renew);
#endif
et->renew_till = malloc(sizeof(*et->renew_till));
*et->renew_till = t;
}
}
et->caddr = b->addresses;
memset(ek, 0, sizeof(*ek));
ek->key = et->key;
/* MIT must have at least one last_req */
ek->last_req.len = 1;
ek->last_req.val = malloc(sizeof(*ek->last_req.val));
ek->last_req.val->lr_type = 0;
ek->last_req.val->lr_value = 0;
ek->nonce = b->nonce;
ek->flags = et->flags;
ek->authtime = et->authtime;
ek->starttime = et->starttime;
ek->endtime = et->endtime;
ek->renew_till = et->renew_till;
ek->srealm = rep->ticket.realm;
ek->sname = rep->ticket.sname;
ek->caddr = et->caddr;
{
unsigned char buf[1024]; /* XXX The data could be indefinite */
int len;
len = encode_EncTicketPart(buf + sizeof(buf) - 1, sizeof(buf), et);
if(len < 0)
return ASN1_OVERFLOW;
rep->ticket.enc_part.etype = ETYPE_DES_CBC_CRC;
rep->ticket.enc_part.kvno = NULL;
krb5_encrypt(context, buf + sizeof(buf) - len, len, &server->keyblock,
&rep->ticket.enc_part.cipher);
len = encode_EncASRepPart(buf + sizeof(buf) - 1, sizeof(buf), ek);
if(len < 0)
return ASN1_OVERFLOW;
rep->enc_part.etype = ETYPE_DES_CBC_CRC;
rep->enc_part.kvno = NULL;
krb5_encrypt(context, buf + sizeof(buf) - len, len, &client->keyblock,
&rep->enc_part.cipher);
len = encode_AS_REP(buf + sizeof(buf) - 1, sizeof(buf), rep);
if(len < 0)
return ASN1_OVERFLOW;
krb5_data_copy(data, buf + sizeof(buf) - len, len);
}
return 0;
}
krb5_error_code
tgs_rep(krb5_context context,
KDC_REQ *req,
KDC_REP *rep,
krb5_data *data)
{
KDC_REQ_BODY *b = &req->req_body;
KDCOptions f = req->req_body.kdc_options;
EncTicketPart *tgt;
hdb_entry *server, *krbtgt, *client;
EncTicketPart *et = calloc(1, sizeof(*et));
EncKDCRepPart *ek = calloc(1, sizeof(*ek));
if(req->padata == NULL || req->padata->len < 1)
return KRB5KDC_ERR_PREAUTH_REQUIRED; /* XXX ??? */
if(req->padata->val->padata_type != pa_tgs_req)
return KRB5KDC_ERR_PADATA_TYPE_NOSUPP;
{
krb5_auth_context ac = NULL;
krb5_principal princ;
krb5_flags ap_req_options;
krb5_ticket *ticket;
krb5_error_code err;
hdb_entry *ent;
err = krb5_build_principal(context,
&princ,
strlen(req->req_body.realm),
req->req_body.realm,
"krbtgt",
req->req_body.realm,
NULL);
if(err) return err;
{
PrincipalName p;
p.name_string.val = calloc(2, sizeof(*p.name_string.val));
p.name_string.len = 2;
p.name_string.val[0] = "krbtgt";
p.name_string.val[1] = req->req_body.realm;
krbtgt = db_fetch(context, &p, req->req_body.realm);
free(p.name_string.val);
}
if(ent == NULL)
return KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
err = krb5_rd_req_with_keyblock(context, &ac,
&req->padata->val->padata_value,
princ,
&krbtgt->keyblock,
&ap_req_options,
&ticket);
if(err)
return err;
/* XXX Check authenticator */
server = db_fetch(context, b->sname, b->realm);
if(server == NULL)
return KRB5KDC_ERR_S_PRINCIPAL_UNKNOWN;
tgt = &ticket->tkt;
client = db_fetch(context, &tgt->cname, tgt->crealm);
if(client == NULL)
return KRB5KDC_ERR_C_PRINCIPAL_UNKNOWN;
memset(rep, 0, sizeof(*rep));
rep->pvno = 5;
rep->msg_type = krb_tgs_rep;
rep->crealm = tgt->crealm;
rep->cname = tgt->cname;
rep->ticket.tkt_vno = 5;
rep->ticket.sname = *b->sname;
rep->ticket.realm = b->realm;
et->caddr = ticket->tkt.caddr;
if(f.forwardable){
if(!tgt->flags.forwardable)
return KRB5KDC_ERR_BADOPTION;
et->flags.forwardable = 1;
}
if(f.forwarded){
if(!tgt->flags.forwardable)
return KRB5KDC_ERR_BADOPTION;
et->flags.forwarded = 1;
et->caddr = req->req_body.addresses;
/* resp.caddr := req.addresses */
}
et->flags.forwarded = tgt->flags.forwarded;
if(f.proxiable){
if(!tgt->flags.proxiable)
return KRB5KDC_ERR_BADOPTION;
et->flags.proxiable = 1;
}
if(f.proxy){
if(!tgt->flags.proxiable)
return KRB5KDC_ERR_BADOPTION;
et->flags.proxy = 1;
et->caddr = req->req_body.addresses;
/* resp.caddr := req.addresses */
}
if(f.allow_postdate){
if(!tgt->flags.may_postdate)
return KRB5KDC_ERR_BADOPTION;
et->flags.may_postdate = 1;
}
if(f.postdated){
if(!tgt->flags.may_postdate)
return KRB5KDC_ERR_BADOPTION;
et->flags.postdated = 1;
et->flags.invalid = 1;
et->starttime = malloc(sizeof(*et->starttime));
*et->starttime = *req->req_body.from;
}
if(f.validate){
if(!tgt->flags.invalid)
return KRB5KDC_ERR_BADOPTION;
if(*tgt->starttime > kdc_time)
return KRB5KRB_AP_ERR_TKT_NYV;
/* XXX tkt = tgt */
et->flags.invalid = 0;
}
/* check for excess flags */
et->authtime = tgt->authtime;
if(f.renew){
time_t old_life;
if(!tgt->flags.renewable)
return KRB5KDC_ERR_BADOPTION;
if(*tgt->renew_till >= kdc_time)
return KRB5KRB_AP_ERR_TKT_EXPIRED;
/* XXX tkt = tgt */
et->starttime = malloc(sizeof(*et->starttime));
*et->starttime = kdc_time;
old_life = tgt->endtime - *tgt->starttime;
et->endtime = MIN(*tgt->renew_till,
*et->starttime + old_life);
}else{
time_t till;
et->starttime = malloc(sizeof(*et->starttime));
*et->starttime = kdc_time;
till = b->till;
if(till == 0)
till = *et->starttime + client->max_life;
till = MIN(till, *et->starttime + client->max_life);
till = MIN(till, *et->starttime + server->max_life);
till = MIN(till, tgt->endtime);
#if 0
till = MIN(till, et->starttime + realm->max_life);
#endif
et->endtime = till;
if(f.renewable_ok &&
et->endtime < b->till &&
tgt->flags.renewable){
f.renewable = 1;
b->rtime = malloc(sizeof(*b->rtime));
*b->rtime = MIN(b->till, *tgt->renew_till);
}
}
if(f.renewable && tgt->flags.renewable && b->rtime){
time_t rtime;
rtime = *b->rtime;
if(rtime == 0)
rtime = *et->starttime + client->max_renew;
et->flags.renewable = 1;
rtime = MIN(rtime, *et->starttime + client->max_renew);
rtime = MIN(rtime, *et->starttime + server->max_renew);
rtime = MIN(rtime, *tgt->renew_till);
#if 0
rtime = MIN(rtime, *et->starttime + realm->max_renew);
#endif
et->renew_till = malloc(sizeof(*et->renew_till));
*et->renew_till = rtime;
}
/* XXX Check enc-authorization-data */
mk_des_keyblock(&et->key);
et->crealm = tgt->crealm;
et->cname = tgt->cname;
et->transited = tgt->transited;
memset(ek, 0, sizeof(*ek));
ek->key = et->key;
/* MIT must have at least one last_req */
ek->last_req.len = 1;
ek->last_req.val = malloc(sizeof(*ek->last_req.val));
ek->last_req.val->lr_type = 0;
ek->last_req.val->lr_value = 0;
ek->nonce = b->nonce;
ek->flags = et->flags;
ek->authtime = et->authtime;
ek->starttime = et->starttime;
ek->endtime = et->endtime;
ek->renew_till = et->renew_till;
ek->srealm = rep->ticket.realm;
ek->sname = rep->ticket.sname;
ek->caddr = et->caddr;
{
unsigned char buf[1024]; /* XXX The data could be indefinite */
int len;
len = encode_EncTicketPart(buf + sizeof(buf) - 1, sizeof(buf), et);
if(len < 0)
return ASN1_OVERFLOW;
rep->ticket.enc_part.etype = ETYPE_DES_CBC_CRC;
rep->ticket.enc_part.kvno = NULL;
krb5_encrypt(context, buf + sizeof(buf) - len, len, &server->keyblock,
&rep->ticket.enc_part.cipher);
len = encode_EncTGSRepPart(buf + sizeof(buf) - 1, sizeof(buf), ek);
if(len < 0)
return ASN1_OVERFLOW;
rep->enc_part.etype = ETYPE_DES_CBC_CRC;
rep->enc_part.kvno = NULL;
{
krb5_keyblock kb;
kb.keytype = tgt->key.keytype;
kb.contents = tgt->key.keyvalue;
krb5_encrypt(context, buf + sizeof(buf) - len, len, &kb,
&rep->enc_part.cipher);
}
len = encode_TGS_REP(buf + sizeof(buf) - 1, sizeof(buf), rep);
if(len < 0)
return ASN1_OVERFLOW;
krb5_data_copy(data, buf + sizeof(buf) - len, len);
}
return 0;
}
}
krb5_error_code
process_request(krb5_context context,
KDC_REQ *req,
krb5_data *reply)
{
krb5_error_code err;
krb5_principal princ;
unsigned char key_buf[1024];
unsigned char *q;
KDC_REP rep;
hdb_entry *cname, *sname;
gettimeofday(&now, NULL);
if(req->msg_type == krb_as_req)
as_rep(context, req, &rep, reply);
else if(req->msg_type == krb_tgs_req)
tgs_rep(context, req, &rep, reply);
else
/* XXX */
return KRB5KRB_AP_ERR_MSG_TYPE;
return 0;
}
int
kerberos(krb5_context context,
unsigned char *buf,
size_t len,
krb5_data *reply)
{
KDC_REQ req;
int i;
i = decode_AS_REQ(buf, len, &req);
if(i >= 0){
return process_request(context, &req, reply);
}
i = decode_TGS_REQ(buf, len, &req);
if(i >= 0){
return process_request(context, &req, reply);
}
return -1;
}
main(int argc, char **argv)
{
krb5_context context;
int s = socket(AF_INET, SOCK_DGRAM, 0);
struct sockaddr_in sin;
int one = 1;
if(s < 0){
perror("socket");
exit(1);
}
krb5_init_context(&context);
memset(&sin, 0, sizeof(sin));
sin.sin_family = AF_INET;
sin.sin_port = htons(88);
if(bind(s, (struct sockaddr*)&sin, sizeof(sin)) < 0){
perror("bind");
exit(1);
}
setsockopt(s, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one));
while(1){
fd_set fds;
unsigned char buf[1024];
size_t len;
FD_ZERO(&fds);
FD_SET(s, &fds);
if(select(s + 1, &fds, NULL, NULL, NULL) < 0){
perror("select");
exit(1);
}
if(FD_ISSET(s, &fds)){
struct sockaddr_in from;
int from_len = sizeof(from);
krb5_error_code err;
krb5_data reply;
len = recvfrom(s, buf, sizeof(buf), 0,
(struct sockaddr*)&from, &from_len);
err = kerberos(context, buf, len, &reply);
if(err){
fprintf(stderr, "%s\n", krb5_get_err_text(context, err));
}else{
sendto(s, reply.data, reply.length, 0,
(struct sockaddr*)&from, from_len);
krb5_data_free(&reply);
}
}
}
}
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