129088Smarkm/*- 229088Smarkm * Copyright (c) 1991, 1993 329088Smarkm * The Regents of the University of California. All rights reserved. 429088Smarkm * 529088Smarkm * Redistribution and use in source and binary forms, with or without 629088Smarkm * modification, are permitted provided that the following conditions 729088Smarkm * are met: 829088Smarkm * 1. Redistributions of source code must retain the above copyright 929088Smarkm * notice, this list of conditions and the following disclaimer. 1029088Smarkm * 2. Redistributions in binary form must reproduce the above copyright 1129088Smarkm * notice, this list of conditions and the following disclaimer in the 1229088Smarkm * documentation and/or other materials provided with the distribution. 1329088Smarkm * 3. All advertising materials mentioning features or use of this software 1429088Smarkm * must display the following acknowledgement: 1529088Smarkm * This product includes software developed by the University of 1629088Smarkm * California, Berkeley and its contributors. 1729088Smarkm * 4. Neither the name of the University nor the names of its contributors 1829088Smarkm * may be used to endorse or promote products derived from this software 1929088Smarkm * without specific prior written permission. 2029088Smarkm * 2129088Smarkm * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 2229088Smarkm * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 2329088Smarkm * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 2429088Smarkm * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 2529088Smarkm * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 2629088Smarkm * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 2729088Smarkm * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 2829088Smarkm * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 2929088Smarkm * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 3029088Smarkm * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 3129088Smarkm * SUCH DAMAGE. 3229088Smarkm */ 3329088Smarkm 3484305Smarkm#include <sys/cdefs.h> 3587139Smarkm 3684305Smarkm__FBSDID("$FreeBSD$"); 3784305Smarkm 3829088Smarkm#ifndef lint 3929181Smarkmstatic const char sccsid[] = "@(#)kerberos.c 8.3 (Berkeley) 5/30/95"; 4029088Smarkm#endif /* not lint */ 4129088Smarkm 4229088Smarkm/* 4329088Smarkm * Copyright (C) 1990 by the Massachusetts Institute of Technology 4429088Smarkm * 4529088Smarkm * Export of this software from the United States of America is assumed 4629088Smarkm * to require a specific license from the United States Government. 4729088Smarkm * It is the responsibility of any person or organization contemplating 4829088Smarkm * export to obtain such a license before exporting. 4929088Smarkm * 5029088Smarkm * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and 5129088Smarkm * distribute this software and its documentation for any purpose and 5229088Smarkm * without fee is hereby granted, provided that the above copyright 5329088Smarkm * notice appear in all copies and that both that copyright notice and 5429088Smarkm * this permission notice appear in supporting documentation, and that 5529088Smarkm * the name of M.I.T. not be used in advertising or publicity pertaining 5629088Smarkm * to distribution of the software without specific, written prior 5729088Smarkm * permission. M.I.T. makes no representations about the suitability of 5829088Smarkm * this software for any purpose. It is provided "as is" without express 5929088Smarkm * or implied warranty. 6029088Smarkm */ 6129088Smarkm 6229088Smarkm#ifdef KRB4 6329088Smarkm#include <sys/types.h> 6429088Smarkm#include <arpa/telnet.h> 6557442Smarkm#include <openssl/des.h> /* BSD wont include this in krb.h, so we do it here */ 6629088Smarkm#include <krb.h> 6787139Smarkm#include <stdio.h> 6829088Smarkm#include <stdlib.h> 6929088Smarkm#include <string.h> 7029088Smarkm 7129088Smarkm#include "encrypt.h" 7229088Smarkm#include "auth.h" 7329088Smarkm#include "misc.h" 7429088Smarkm 7587155Smarkmint kerberos4_cksum(unsigned char *, int); 7687155Smarkmint kuserok(AUTH_DAT *, char *); 7729088Smarkm 7887139Smarkmextern int auth_debug_mode; 7929088Smarkm 8029088Smarkmstatic unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0, 8129088Smarkm AUTHTYPE_KERBEROS_V4, }; 8229088Smarkm 8329088Smarkm#define KRB_AUTH 0 /* Authentication data follows */ 8429088Smarkm#define KRB_REJECT 1 /* Rejected (reason might follow) */ 8529088Smarkm#define KRB_ACCEPT 2 /* Accepted */ 8629088Smarkm#define KRB_CHALLENGE 3 /* Challenge for mutual auth. */ 8729088Smarkm#define KRB_RESPONSE 4 /* Response for mutual auth. */ 8829088Smarkm 8929088Smarkmstatic KTEXT_ST auth; 9029088Smarkmstatic char name[ANAME_SZ]; 9187139Smarkmstatic AUTH_DAT adat = { 0, "", "", "", 0, {}, 0, 0, 0, { 0, "", 0 } }; 9229088Smarkm#ifdef ENCRYPTION 9329088Smarkmstatic Block session_key = { 0 }; 9429181Smarkmstatic des_key_schedule sched; 9529088Smarkmstatic Block challenge = { 0 }; 9629088Smarkm#endif /* ENCRYPTION */ 9729088Smarkm 9887139Smarkmstatic char krb_service_name[] = "rcmd"; 9987139Smarkmstatic char empty[] = ""; 10087139Smarkm 10187139Smarkmstatic int 10287139SmarkmData(Authenticator *ap, int type, const unsigned char *d, int c) 10329088Smarkm{ 10429088Smarkm unsigned char *p = str_data + 4; 10587139Smarkm const unsigned char *cd = d; 10629088Smarkm 10729088Smarkm if (c == -1) 10887139Smarkm c = strlen(cd); 10929088Smarkm 11029088Smarkm if (auth_debug_mode) { 11129088Smarkm printf("%s:%d: [%d] (%d)", 11229088Smarkm str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY", 11329088Smarkm str_data[3], 11429088Smarkm type, c); 11529088Smarkm printd(d, c); 11629088Smarkm printf("\r\n"); 11729088Smarkm } 11829088Smarkm *p++ = ap->type; 11929088Smarkm *p++ = ap->way; 12029088Smarkm *p++ = type; 12129088Smarkm while (c-- > 0) { 12229088Smarkm if ((*p++ = *cd++) == IAC) 12329088Smarkm *p++ = IAC; 12429088Smarkm } 12529088Smarkm *p++ = IAC; 12629088Smarkm *p++ = SE; 12729088Smarkm if (str_data[3] == TELQUAL_IS) 12829088Smarkm printsub('>', &str_data[2], p - (&str_data[2])); 12929088Smarkm return(net_write(str_data, p - str_data)); 13029088Smarkm} 13129088Smarkm 13287139Smarkmint 13387139Smarkmkerberos4_init(Authenticator *ap __unused, int server) 13429088Smarkm{ 13529088Smarkm FILE *fp; 13629088Smarkm 13729088Smarkm if (server) { 13829088Smarkm str_data[3] = TELQUAL_REPLY; 13929088Smarkm if ((fp = fopen(KEYFILE, "r")) == NULL) 14029088Smarkm return(0); 14129088Smarkm fclose(fp); 14229088Smarkm } else { 14329088Smarkm str_data[3] = TELQUAL_IS; 14429088Smarkm } 14529088Smarkm return(1); 14629088Smarkm} 14729088Smarkm 14829088Smarkmchar dst_realm_buf[REALM_SZ], *dest_realm = NULL; 14929088Smarkmint dst_realm_sz = REALM_SZ; 15029088Smarkm 15187139Smarkmint 15287139Smarkmkerberos4_send(Authenticator *ap) 15329088Smarkm{ 15487139Smarkm KTEXT_ST lauth; 15529088Smarkm char instance[INST_SZ]; 15629088Smarkm char *realm; 15729088Smarkm CREDENTIALS cred; 15829088Smarkm int r; 15929088Smarkm 16029088Smarkm printf("[ Trying KERBEROS4 ... ]\n"); 16129088Smarkm if (!UserNameRequested) { 16229088Smarkm if (auth_debug_mode) { 16329088Smarkm printf("Kerberos V4: no user name supplied\r\n"); 16429088Smarkm } 16529088Smarkm return(0); 16629088Smarkm } 16729088Smarkm 16829088Smarkm memset(instance, 0, sizeof(instance)); 16929088Smarkm 17029181Smarkm if ((realm = krb_get_phost(RemoteHostName))) 17129088Smarkm strncpy(instance, realm, sizeof(instance)); 17229088Smarkm 17329088Smarkm instance[sizeof(instance)-1] = '\0'; 17429088Smarkm 17529088Smarkm realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName); 17629088Smarkm 17729088Smarkm if (!realm) { 17829088Smarkm printf("Kerberos V4: no realm for %s\r\n", RemoteHostName); 17929088Smarkm return(0); 18029088Smarkm } 18187139Smarkm if ((r = krb_mk_req(&lauth, krb_service_name, instance, realm, 0L))) { 18229088Smarkm printf("mk_req failed: %s\r\n", krb_err_txt[r]); 18329088Smarkm return(0); 18429088Smarkm } 18587139Smarkm if ((r = krb_get_cred(krb_service_name, instance, realm, &cred))) { 18629088Smarkm printf("get_cred failed: %s\r\n", krb_err_txt[r]); 18729088Smarkm return(0); 18829088Smarkm } 18929088Smarkm if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) { 19029088Smarkm if (auth_debug_mode) 19129088Smarkm printf("Not enough room for user name\r\n"); 19229088Smarkm return(0); 19329088Smarkm } 19429088Smarkm if (auth_debug_mode) 19587139Smarkm printf("Sent %d bytes of authentication data\r\n", lauth.length); 19687139Smarkm if (!Data(ap, KRB_AUTH, (void *)lauth.dat, lauth.length)) { 19729088Smarkm if (auth_debug_mode) 19829088Smarkm printf("Not enough room for authentication data\r\n"); 19929088Smarkm return(0); 20029088Smarkm } 20129088Smarkm#ifdef ENCRYPTION 20229088Smarkm /* 20329088Smarkm * If we are doing mutual authentication, get set up to send 20429088Smarkm * the challenge, and verify it when the response comes back. 20529088Smarkm */ 20629088Smarkm if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { 20729088Smarkm register int i; 20829088Smarkm 20929181Smarkm des_key_sched(&cred.session, sched); 210110049Snectar des_random_key(&session_key); 21129181Smarkm des_ecb_encrypt(&session_key, &session_key, sched, 0); 21229181Smarkm des_ecb_encrypt(&session_key, &challenge, sched, 0); 21329088Smarkm /* 21429088Smarkm * Increment the challenge by 1, and encrypt it for 21529088Smarkm * later comparison. 21629088Smarkm */ 21729088Smarkm for (i = 7; i >= 0; --i) { 21829088Smarkm register int x; 21929088Smarkm x = (unsigned int)challenge[i] + 1; 22029088Smarkm challenge[i] = x; /* ignore overflow */ 22129088Smarkm if (x < 256) /* if no overflow, all done */ 22229088Smarkm break; 22329088Smarkm } 22429181Smarkm des_ecb_encrypt(&challenge, &challenge, sched, 1); 22529088Smarkm } 22629088Smarkm#endif /* ENCRYPTION */ 22729088Smarkm 22829088Smarkm if (auth_debug_mode) { 22987139Smarkm printf("CK: %d:", kerberos4_cksum(lauth.dat, lauth.length)); 23087139Smarkm printd(lauth.dat, lauth.length); 23129088Smarkm printf("\r\n"); 23229088Smarkm printf("Sent Kerberos V4 credentials to server\r\n"); 23329088Smarkm } 23429088Smarkm return(1); 23529088Smarkm} 23629088Smarkm 23787139Smarkmvoid 23887139Smarkmkerberos4_is(Authenticator *ap, unsigned char *data, int cnt) 23929088Smarkm{ 24029088Smarkm#ifdef ENCRYPTION 24129088Smarkm Session_Key skey; 24229088Smarkm Block datablock; 24329088Smarkm#endif /* ENCRYPTION */ 24429088Smarkm char realm[REALM_SZ]; 24529088Smarkm char instance[INST_SZ]; 24629088Smarkm int r; 24729088Smarkm 24829088Smarkm if (cnt-- < 1) 24929088Smarkm return; 25029088Smarkm switch (*data++) { 25129088Smarkm case KRB_AUTH: 25229088Smarkm if (krb_get_lrealm(realm, 1) != KSUCCESS) { 25387139Smarkm Data(ap, KRB_REJECT, "No local V4 Realm.", -1); 25429088Smarkm auth_finished(ap, AUTH_REJECT); 25529088Smarkm if (auth_debug_mode) 25629088Smarkm printf("No local realm\r\n"); 25729088Smarkm return; 25829088Smarkm } 25929088Smarkm memmove((void *)auth.dat, (void *)data, auth.length = cnt); 26029088Smarkm if (auth_debug_mode) { 26129088Smarkm printf("Got %d bytes of authentication data\r\n", cnt); 26229088Smarkm printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length)); 26329088Smarkm printd(auth.dat, auth.length); 26429088Smarkm printf("\r\n"); 26529088Smarkm } 26629088Smarkm instance[0] = '*'; instance[1] = 0; 26787139Smarkm if ((r = krb_rd_req(&auth, krb_service_name, 26887139Smarkm instance, 0, &adat, empty))) { 26929088Smarkm if (auth_debug_mode) 27029088Smarkm printf("Kerberos failed him as %s\r\n", name); 27187139Smarkm Data(ap, KRB_REJECT, krb_err_txt[r], -1); 27229088Smarkm auth_finished(ap, AUTH_REJECT); 27329088Smarkm return; 27429088Smarkm } 27529088Smarkm#ifdef ENCRYPTION 27629088Smarkm memmove((void *)session_key, (void *)adat.session, sizeof(Block)); 27729088Smarkm#endif /* ENCRYPTION */ 27829088Smarkm krb_kntoln(&adat, name); 27929088Smarkm 28029088Smarkm if (UserNameRequested && !kuserok(&adat, UserNameRequested)) 28187139Smarkm Data(ap, KRB_ACCEPT, NULL, 0); 28229088Smarkm else 28387139Smarkm Data(ap, KRB_REJECT, "user is not authorized", -1); 28429088Smarkm auth_finished(ap, AUTH_USER); 28529088Smarkm break; 28629088Smarkm 28729088Smarkm case KRB_CHALLENGE: 28829088Smarkm#ifndef ENCRYPTION 28987139Smarkm Data(ap, KRB_RESPONSE, NULL, 0); 29029088Smarkm#else /* ENCRYPTION */ 29129088Smarkm if (!VALIDKEY(session_key)) { 29229088Smarkm /* 29329088Smarkm * We don't have a valid session key, so just 29429088Smarkm * send back a response with an empty session 29529088Smarkm * key. 29629088Smarkm */ 29787139Smarkm Data(ap, KRB_RESPONSE, NULL, 0); 29829088Smarkm break; 29929088Smarkm } 30029088Smarkm 30129181Smarkm des_key_sched(&session_key, sched); 30229088Smarkm memmove((void *)datablock, (void *)data, sizeof(Block)); 30329088Smarkm /* 30429088Smarkm * Take the received encrypted challenge, and encrypt 30529088Smarkm * it again to get a unique session_key for the 30629088Smarkm * ENCRYPT option. 30729088Smarkm */ 30829181Smarkm des_ecb_encrypt(&datablock, &session_key, sched, 1); 30929088Smarkm skey.type = SK_DES; 31029088Smarkm skey.length = 8; 31129088Smarkm skey.data = session_key; 31229088Smarkm encrypt_session_key(&skey, 1); 31329088Smarkm /* 31429088Smarkm * Now decrypt the received encrypted challenge, 31529088Smarkm * increment by one, re-encrypt it and send it back. 31629088Smarkm */ 31729181Smarkm des_ecb_encrypt(&datablock, &challenge, sched, 0); 31829088Smarkm for (r = 7; r >= 0; r--) { 31929088Smarkm register int t; 32029088Smarkm t = (unsigned int)challenge[r] + 1; 32129088Smarkm challenge[r] = t; /* ignore overflow */ 32229088Smarkm if (t < 256) /* if no overflow, all done */ 32329088Smarkm break; 32429088Smarkm } 32529181Smarkm des_ecb_encrypt(&challenge, &challenge, sched, 1); 32687139Smarkm Data(ap, KRB_RESPONSE, challenge, sizeof(challenge)); 32729088Smarkm#endif /* ENCRYPTION */ 32829088Smarkm break; 32929088Smarkm 33029088Smarkm default: 33129088Smarkm if (auth_debug_mode) 33229088Smarkm printf("Unknown Kerberos option %d\r\n", data[-1]); 33387139Smarkm Data(ap, KRB_REJECT, NULL, 0); 33429088Smarkm break; 33529088Smarkm } 33629088Smarkm} 33729088Smarkm 33887139Smarkmvoid 33987139Smarkmkerberos4_reply(Authenticator *ap, unsigned char *data, int cnt) 34029088Smarkm{ 34129088Smarkm#ifdef ENCRYPTION 34229088Smarkm Session_Key skey; 34329088Smarkm#endif /* ENCRYPTION */ 34429088Smarkm 34529088Smarkm if (cnt-- < 1) 34629088Smarkm return; 34729088Smarkm switch (*data++) { 34829088Smarkm case KRB_REJECT: 34929088Smarkm if (cnt > 0) { 35029088Smarkm printf("[ Kerberos V4 refuses authentication because %.*s ]\r\n", 35129088Smarkm cnt, data); 35229088Smarkm } else 35329088Smarkm printf("[ Kerberos V4 refuses authentication ]\r\n"); 35429088Smarkm auth_send_retry(); 35529088Smarkm return; 35629088Smarkm case KRB_ACCEPT: 35729088Smarkm printf("[ Kerberos V4 accepts you ]\n"); 35829088Smarkm if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { 35929088Smarkm /* 36029088Smarkm * Send over the encrypted challenge. 36129088Smarkm */ 36229088Smarkm#ifndef ENCRYPTION 36387139Smarkm Data(ap, KRB_CHALLENGE, NULL, 0); 36429088Smarkm#else /* ENCRYPTION */ 36587139Smarkm Data(ap, KRB_CHALLENGE, session_key, 36629088Smarkm sizeof(session_key)); 36729181Smarkm des_ecb_encrypt(&session_key, &session_key, sched, 1); 36829088Smarkm skey.type = SK_DES; 36929088Smarkm skey.length = 8; 37029088Smarkm skey.data = session_key; 37129088Smarkm encrypt_session_key(&skey, 0); 37229088Smarkm#endif /* ENCRYPTION */ 37329088Smarkm return; 37429088Smarkm } 37529088Smarkm auth_finished(ap, AUTH_USER); 37629088Smarkm return; 37729088Smarkm case KRB_RESPONSE: 37829088Smarkm#ifdef ENCRYPTION 37929088Smarkm /* 38029088Smarkm * Verify that the response to the challenge is correct. 38129088Smarkm */ 38229088Smarkm if ((cnt != sizeof(Block)) || 38329088Smarkm (0 != memcmp((void *)data, (void *)challenge, 38429088Smarkm sizeof(challenge)))) 38529088Smarkm { 38629088Smarkm#endif /* ENCRYPTION */ 38729088Smarkm printf("[ Kerberos V4 challenge failed!!! ]\r\n"); 38829088Smarkm auth_send_retry(); 38929088Smarkm return; 39029088Smarkm#ifdef ENCRYPTION 39129088Smarkm } 39229088Smarkm printf("[ Kerberos V4 challenge successful ]\r\n"); 39329088Smarkm auth_finished(ap, AUTH_USER); 39429088Smarkm#endif /* ENCRYPTION */ 39529088Smarkm break; 39629088Smarkm default: 39729088Smarkm if (auth_debug_mode) 39829088Smarkm printf("Unknown Kerberos option %d\r\n", data[-1]); 39929088Smarkm return; 40029088Smarkm } 40129088Smarkm} 40229088Smarkm 40387139Smarkmint 40487139Smarkmkerberos4_status(Authenticator *ap __unused, char *nam, int level) 40529088Smarkm{ 40629088Smarkm if (level < AUTH_USER) 40729088Smarkm return(level); 40829088Smarkm 40929088Smarkm if (UserNameRequested && !kuserok(&adat, UserNameRequested)) { 41087139Smarkm strcpy(nam, UserNameRequested); 41129088Smarkm return(AUTH_VALID); 41229088Smarkm } else 41329088Smarkm return(AUTH_USER); 41429088Smarkm} 41529088Smarkm 41629088Smarkm#define BUMP(buf, len) while (*(buf)) {++(buf), --(len);} 41729088Smarkm#define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);} 41829088Smarkm 41987139Smarkmvoid 42087139Smarkmkerberos4_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen) 42129088Smarkm{ 42229088Smarkm char lbuf[32]; 42329088Smarkm register int i; 42429088Smarkm 42529088Smarkm buf[buflen-1] = '\0'; /* make sure its NULL terminated */ 42629088Smarkm buflen -= 1; 42729088Smarkm 42829088Smarkm switch(data[3]) { 42929088Smarkm case KRB_REJECT: /* Rejected (reason might follow) */ 43029088Smarkm strncpy((char *)buf, " REJECT ", buflen); 43129088Smarkm goto common; 43229088Smarkm 43329088Smarkm case KRB_ACCEPT: /* Accepted (name might follow) */ 43429088Smarkm strncpy((char *)buf, " ACCEPT ", buflen); 43529088Smarkm common: 43629088Smarkm BUMP(buf, buflen); 43729088Smarkm if (cnt <= 4) 43829088Smarkm break; 43929088Smarkm ADDC(buf, buflen, '"'); 44029088Smarkm for (i = 4; i < cnt; i++) 44129088Smarkm ADDC(buf, buflen, data[i]); 44229088Smarkm ADDC(buf, buflen, '"'); 44329088Smarkm ADDC(buf, buflen, '\0'); 44429088Smarkm break; 44529088Smarkm 44629088Smarkm case KRB_AUTH: /* Authentication data follows */ 44729088Smarkm strncpy((char *)buf, " AUTH", buflen); 44829088Smarkm goto common2; 44929088Smarkm 45029088Smarkm case KRB_CHALLENGE: 45129088Smarkm strncpy((char *)buf, " CHALLENGE", buflen); 45229088Smarkm goto common2; 45329088Smarkm 45429088Smarkm case KRB_RESPONSE: 45529088Smarkm strncpy((char *)buf, " RESPONSE", buflen); 45629088Smarkm goto common2; 45729088Smarkm 45829088Smarkm default: 45929088Smarkm sprintf(lbuf, " %d (unknown)", data[3]); 46029088Smarkm strncpy((char *)buf, lbuf, buflen); 46129088Smarkm common2: 46229088Smarkm BUMP(buf, buflen); 46329088Smarkm for (i = 4; i < cnt; i++) { 46429088Smarkm sprintf(lbuf, " %d", data[i]); 46529088Smarkm strncpy((char *)buf, lbuf, buflen); 46629088Smarkm BUMP(buf, buflen); 46729088Smarkm } 46829088Smarkm break; 46929088Smarkm } 47029088Smarkm} 47129088Smarkm 47287139Smarkmint 47387139Smarkmkerberos4_cksum(unsigned char *d, int n) 47429088Smarkm{ 47529088Smarkm int ck = 0; 47629088Smarkm 47729088Smarkm /* 47829088Smarkm * A comment is probably needed here for those not 47929088Smarkm * well versed in the "C" language. Yes, this is 48029088Smarkm * supposed to be a "switch" with the body of the 48129088Smarkm * "switch" being a "while" statement. The whole 48229088Smarkm * purpose of the switch is to allow us to jump into 48329088Smarkm * the middle of the while() loop, and then not have 48429088Smarkm * to do any more switch()s. 48529088Smarkm * 48629088Smarkm * Some compilers will spit out a warning message 48729088Smarkm * about the loop not being entered at the top. 48829088Smarkm */ 48929088Smarkm switch (n&03) 49029088Smarkm while (n > 0) { 49129088Smarkm case 0: 49229088Smarkm ck ^= (int)*d++ << 24; 49329088Smarkm --n; 49429088Smarkm case 3: 49529088Smarkm ck ^= (int)*d++ << 16; 49629088Smarkm --n; 49729088Smarkm case 2: 49829088Smarkm ck ^= (int)*d++ << 8; 49929088Smarkm --n; 50029088Smarkm case 1: 50129088Smarkm ck ^= (int)*d++; 50229088Smarkm --n; 50329088Smarkm } 50429088Smarkm return(ck); 50529088Smarkm} 50629088Smarkm#endif 507