325 lines
11 KiB
C
325 lines
11 KiB
C
/*
|
|
* Copyright (c) 1995, 1996, 1997, 1998 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 "krb_locl.h"
|
|
|
|
RCSID("$Id: rd_req.c,v 1.1.1.2 2000/12/29 01:43:18 assar Exp $");
|
|
|
|
static struct timeval t_local = { 0, 0 };
|
|
|
|
/*
|
|
* Keep the following information around for subsequent calls
|
|
* to this routine by the same server using the same key.
|
|
*/
|
|
|
|
static des_key_schedule serv_key; /* Key sched to decrypt ticket */
|
|
static des_cblock ky; /* Initialization vector */
|
|
static int st_kvno; /* version number for this key */
|
|
static char st_rlm[REALM_SZ]; /* server's realm */
|
|
static char st_nam[ANAME_SZ]; /* service name */
|
|
static char st_inst[INST_SZ]; /* server's instance */
|
|
|
|
/*
|
|
* This file contains two functions. krb_set_key() takes a DES
|
|
* key or password string and returns a DES key (either the original
|
|
* key, or the password converted into a DES key) and a key schedule
|
|
* for it.
|
|
*
|
|
* krb_rd_req() reads an authentication request and returns information
|
|
* about the identity of the requestor, or an indication that the
|
|
* identity information was not authentic.
|
|
*/
|
|
|
|
/*
|
|
* krb_set_key() takes as its first argument either a DES key or a
|
|
* password string. The "cvt" argument indicates how the first
|
|
* argument "key" is to be interpreted: if "cvt" is null, "key" is
|
|
* taken to be a DES key; if "cvt" is non-null, "key" is taken to
|
|
* be a password string, and is converted into a DES key using
|
|
* string_to_key(). In either case, the resulting key is returned
|
|
* in the external static variable "ky". A key schedule is
|
|
* generated for "ky" and returned in the external static variable
|
|
* "serv_key".
|
|
*
|
|
* This routine returns the return value of des_key_sched.
|
|
*
|
|
* krb_set_key() needs to be in the same .o file as krb_rd_req() so that
|
|
* the key set by krb_set_key() is available in private storage for
|
|
* krb_rd_req().
|
|
*/
|
|
|
|
int
|
|
krb_set_key(void *key, int cvt)
|
|
{
|
|
#ifdef NOENCRYPTION
|
|
memset(ky, 0, sizeof(ky));
|
|
return KSUCCESS;
|
|
#else /* Encrypt */
|
|
if (cvt)
|
|
des_string_to_key((char*)key, &ky);
|
|
else
|
|
memcpy((char*)ky, key, 8);
|
|
return(des_key_sched(&ky, serv_key));
|
|
#endif /* NOENCRYPTION */
|
|
}
|
|
|
|
|
|
/*
|
|
* krb_rd_req() takes an AUTH_MSG_APPL_REQUEST or
|
|
* AUTH_MSG_APPL_REQUEST_MUTUAL message created by krb_mk_req(),
|
|
* checks its integrity and returns a judgement as to the requestor's
|
|
* identity.
|
|
*
|
|
* The "authent" argument is a pointer to the received message.
|
|
* The "service" and "instance" arguments name the receiving server,
|
|
* and are used to get the service's ticket to decrypt the ticket
|
|
* in the message, and to compare against the server name inside the
|
|
* ticket. "from_addr" is the network address of the host from which
|
|
* the message was received; this is checked against the network
|
|
* address in the ticket. If "from_addr" is zero, the check is not
|
|
* performed. "ad" is an AUTH_DAT structure which is
|
|
* filled in with information about the sender's identity according
|
|
* to the authenticator and ticket sent in the message. Finally,
|
|
* "fn" contains the name of the file containing the server's key.
|
|
* (If "fn" is NULL, the server's key is assumed to have been set
|
|
* by krb_set_key(). If "fn" is the null string ("") the default
|
|
* file KEYFILE, defined in "krb.h", is used.)
|
|
*
|
|
* krb_rd_req() returns RD_AP_OK if the authentication information
|
|
* was genuine, or one of the following error codes (defined in
|
|
* "krb.h"):
|
|
*
|
|
* RD_AP_VERSION - wrong protocol version number
|
|
* RD_AP_MSG_TYPE - wrong message type
|
|
* RD_AP_UNDEC - couldn't decipher the message
|
|
* RD_AP_INCON - inconsistencies found
|
|
* RD_AP_BADD - wrong network address
|
|
* RD_AP_TIME - client time (in authenticator)
|
|
* too far off server time
|
|
* RD_AP_NYV - Kerberos time (in ticket) too
|
|
* far off server time
|
|
* RD_AP_EXP - ticket expired
|
|
*
|
|
* For the message format, see krb_mk_req().
|
|
*
|
|
* Mutual authentication is not implemented.
|
|
*/
|
|
|
|
int
|
|
krb_rd_req(KTEXT authent, /* The received message */
|
|
char *service, /* Service name */
|
|
char *instance, /* Service instance */
|
|
int32_t from_addr, /* Net address of originating host */
|
|
AUTH_DAT *ad, /* Structure to be filled in */
|
|
char *a_fn) /* Filename to get keys from */
|
|
{
|
|
static KTEXT_ST ticket; /* Temp storage for ticket */
|
|
static KTEXT tkt = &ticket;
|
|
static KTEXT_ST req_id_st; /* Temp storage for authenticator */
|
|
KTEXT req_id = &req_id_st;
|
|
|
|
char realm[REALM_SZ]; /* Realm of issuing kerberos */
|
|
|
|
unsigned char skey[KKEY_SZ]; /* Session key from ticket */
|
|
char sname[SNAME_SZ]; /* Service name from ticket */
|
|
char iname[INST_SZ]; /* Instance name from ticket */
|
|
char r_aname[ANAME_SZ]; /* Client name from authenticator */
|
|
char r_inst[INST_SZ]; /* Client instance from authenticator */
|
|
char r_realm[REALM_SZ]; /* Client realm from authenticator */
|
|
u_int32_t r_time_sec; /* Coarse time from authenticator */
|
|
unsigned long delta_t; /* Time in authenticator - local time */
|
|
long tkt_age; /* Age of ticket */
|
|
static unsigned char s_kvno;/* Version number of the server's key
|
|
* Kerberos used to encrypt ticket */
|
|
|
|
struct timeval tv;
|
|
int status;
|
|
|
|
int pvno;
|
|
int type;
|
|
int little_endian;
|
|
|
|
const char *fn = a_fn;
|
|
|
|
unsigned char *p;
|
|
|
|
if (authent->length <= 0)
|
|
return(RD_AP_MODIFIED);
|
|
|
|
p = authent->dat;
|
|
|
|
/* get msg version, type and byte order, and server key version */
|
|
|
|
pvno = *p++;
|
|
|
|
if(pvno != KRB_PROT_VERSION)
|
|
return RD_AP_VERSION;
|
|
|
|
type = *p++;
|
|
|
|
little_endian = type & 1;
|
|
type &= ~1;
|
|
|
|
if(type != AUTH_MSG_APPL_REQUEST && type != AUTH_MSG_APPL_REQUEST_MUTUAL)
|
|
return RD_AP_MSG_TYPE;
|
|
|
|
s_kvno = *p++;
|
|
|
|
p += krb_get_string(p, realm, sizeof(realm));
|
|
|
|
/*
|
|
* If "fn" is NULL, key info should already be set; don't
|
|
* bother with ticket file. Otherwise, check to see if we
|
|
* already have key info for the given server and key version
|
|
* (saved in the static st_* variables). If not, go get it
|
|
* from the ticket file. If "fn" is the null string, use the
|
|
* default ticket file.
|
|
*/
|
|
if (fn && (strcmp(st_nam,service) || strcmp(st_inst,instance) ||
|
|
strcmp(st_rlm,realm) || (st_kvno != s_kvno))) {
|
|
if (*fn == 0) fn = (char *)KEYFILE;
|
|
st_kvno = s_kvno;
|
|
if (read_service_key(service, instance, realm, s_kvno,
|
|
fn, (char *)skey))
|
|
return(RD_AP_UNDEC);
|
|
if ((status = krb_set_key((char*)skey, 0)))
|
|
return(status);
|
|
strlcpy (st_rlm, realm, REALM_SZ);
|
|
strlcpy (st_nam, service, SNAME_SZ);
|
|
strlcpy (st_inst, instance, INST_SZ);
|
|
}
|
|
|
|
tkt->length = *p++;
|
|
|
|
req_id->length = *p++;
|
|
|
|
if(tkt->length + (p - authent->dat) > authent->length)
|
|
return RD_AP_MODIFIED;
|
|
|
|
memcpy(tkt->dat, p, tkt->length);
|
|
p += tkt->length;
|
|
|
|
if (krb_ap_req_debug)
|
|
krb_log("ticket->length: %d",tkt->length);
|
|
|
|
/* Decrypt and take apart ticket */
|
|
if (decomp_ticket(tkt, &ad->k_flags, ad->pname, ad->pinst, ad->prealm,
|
|
&ad->address, ad->session, &ad->life,
|
|
&ad->time_sec, sname, iname, &ky, serv_key))
|
|
return RD_AP_UNDEC;
|
|
|
|
if (krb_ap_req_debug) {
|
|
krb_log("Ticket Contents.");
|
|
krb_log(" Aname: %s.%s",ad->pname, ad->prealm);
|
|
krb_log(" Service: %s", krb_unparse_name_long(sname, iname, NULL));
|
|
}
|
|
|
|
/* Extract the authenticator */
|
|
|
|
if(req_id->length + (p - authent->dat) > authent->length)
|
|
return RD_AP_MODIFIED;
|
|
|
|
memcpy(req_id->dat, p, req_id->length);
|
|
p = req_id->dat;
|
|
|
|
#ifndef NOENCRYPTION
|
|
/* And decrypt it with the session key from the ticket */
|
|
if (krb_ap_req_debug) krb_log("About to decrypt authenticator");
|
|
|
|
encrypt_ktext(req_id, &ad->session, DES_DECRYPT);
|
|
|
|
if (krb_ap_req_debug) krb_log("Done.");
|
|
#endif /* NOENCRYPTION */
|
|
|
|
/* cast req_id->length to int? */
|
|
#define check_ptr() if ((ptr - (char *) req_id->dat) > req_id->length) return(RD_AP_MODIFIED);
|
|
|
|
p += krb_get_nir(p,
|
|
r_aname, sizeof(r_aname),
|
|
r_inst, sizeof(r_inst),
|
|
r_realm, sizeof(r_realm));
|
|
|
|
p += krb_get_int(p, &ad->checksum, 4, little_endian);
|
|
|
|
p++; /* time_5ms is not used */
|
|
|
|
p += krb_get_int(p, &r_time_sec, 4, little_endian);
|
|
|
|
/* Check for authenticity of the request */
|
|
if (krb_ap_req_debug)
|
|
krb_log("Principal: %s.%s@%s / %s.%s@%s",ad->pname,ad->pinst, ad->prealm,
|
|
r_aname, r_inst, r_realm);
|
|
if (strcmp(ad->pname, r_aname) != 0 ||
|
|
strcmp(ad->pinst, r_inst) != 0 ||
|
|
strcmp(ad->prealm, r_realm) != 0)
|
|
return RD_AP_INCON;
|
|
|
|
if (krb_ap_req_debug)
|
|
krb_log("Address: %x %x", ad->address, from_addr);
|
|
|
|
if (from_addr && (!krb_equiv(ad->address, from_addr)))
|
|
return RD_AP_BADD;
|
|
|
|
gettimeofday(&tv, NULL);
|
|
delta_t = abs((int)(tv.tv_sec - r_time_sec));
|
|
if (delta_t > CLOCK_SKEW) {
|
|
if (krb_ap_req_debug)
|
|
krb_log("Time out of range: %lu - %lu = %lu",
|
|
(unsigned long)t_local.tv_sec,
|
|
(unsigned long)r_time_sec,
|
|
(unsigned long)delta_t);
|
|
return RD_AP_TIME;
|
|
}
|
|
|
|
/* Now check for expiration of ticket */
|
|
|
|
tkt_age = tv.tv_sec - ad->time_sec;
|
|
if (krb_ap_req_debug)
|
|
krb_log("Time: %ld Issue Date: %lu Diff: %ld Life %x",
|
|
(long)tv.tv_sec,
|
|
(unsigned long)ad->time_sec,
|
|
tkt_age,
|
|
ad->life);
|
|
|
|
if ((tkt_age < 0) && (-tkt_age > CLOCK_SKEW))
|
|
return RD_AP_NYV;
|
|
|
|
if (tv.tv_sec > krb_life_to_time(ad->time_sec, ad->life))
|
|
return RD_AP_EXP;
|
|
|
|
/* All seems OK */
|
|
ad->reply.length = 0;
|
|
|
|
return(RD_AP_OK);
|
|
}
|