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NetBSD/crypto/dist/krb4/lib/krb/rd_req.c

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/*
* 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("$KTH-KRB: rd_req.c,v 1.28 2000/05/15 00:19:38 assar Exp $"
"$NetBSD: rd_req.c,v 1.1.1.4 2002/09/12 12:22:10 joda 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 = 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);
}
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