diff options
Diffstat (limited to 'lib/libtelnet/kerberos.c')
| -rw-r--r-- | lib/libtelnet/kerberos.c | 554 |
1 files changed, 554 insertions, 0 deletions
diff --git a/lib/libtelnet/kerberos.c b/lib/libtelnet/kerberos.c new file mode 100644 index 0000000..aa9b418 --- /dev/null +++ b/lib/libtelnet/kerberos.c @@ -0,0 +1,554 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. 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. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * This product includes software developed by the University of + * California, Berkeley and its contributors. + * 4. Neither the name of the University 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 REGENTS 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 REGENTS 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. + */ + +#ifndef lint +static char sccsid[] = "@(#)kerberos.c 8.1 (Berkeley) 6/4/93"; +#endif /* not lint */ + +/* + * Copyright (C) 1990 by the Massachusetts Institute of Technology + * + * Export of this software from the United States of America is assumed + * to require a specific license from the United States Government. + * It is the responsibility of any person or organization contemplating + * export to obtain such a license before exporting. + * + * WITHIN THAT CONSTRAINT, permission to use, copy, modify, and + * distribute this software and its documentation for any purpose and + * without fee is hereby granted, provided that the above copyright + * notice appear in all copies and that both that copyright notice and + * this permission notice appear in supporting documentation, and that + * the name of M.I.T. not be used in advertising or publicity pertaining + * to distribution of the software without specific, written prior + * permission. M.I.T. makes no representations about the suitability of + * this software for any purpose. It is provided "as is" without express + * or implied warranty. + */ + +#ifdef KRB4 +#include <sys/types.h> +#include <arpa/telnet.h> +#include <stdio.h> +#include <des.h> /* BSD wont include this in krb.h, so we do it here */ +#include <krb.h> +#ifdef __STDC__ +#include <stdlib.h> +#endif +#ifdef NO_STRING_H +#include <strings.h> +#else +#include <string.h> +#endif + +#include "encrypt.h" +#include "auth.h" +#include "misc.h" + +int kerberos4_cksum P((unsigned char *, int)); +int krb_mk_req P((KTEXT, char *, char *, char *, u_long)); +int krb_rd_req P((KTEXT, char *, char *, u_long, AUTH_DAT *, char *)); +int krb_kntoln P((AUTH_DAT *, char *)); +int krb_get_cred P((char *, char *, char *, CREDENTIALS *)); +int krb_get_lrealm P((char *, int)); +int kuserok P((AUTH_DAT *, char *)); + +extern auth_debug_mode; + +static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0, + AUTHTYPE_KERBEROS_V4, }; +static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION, + TELQUAL_NAME, }; + +#define KRB_AUTH 0 /* Authentication data follows */ +#define KRB_REJECT 1 /* Rejected (reason might follow) */ +#define KRB_ACCEPT 2 /* Accepted */ +#define KRB_CHALLENGE 3 /* Challenge for mutual auth. */ +#define KRB_RESPONSE 4 /* Response for mutual auth. */ + +#define KRB_SERVICE_NAME "rcmd" + +static KTEXT_ST auth; +static char name[ANAME_SZ]; +static AUTH_DAT adat = { 0 }; +#ifdef ENCRYPTION +static Block session_key = { 0 }; +static Schedule sched; +static Block challenge = { 0 }; +#endif /* ENCRYPTION */ + + static int +Data(ap, type, d, c) + Authenticator *ap; + int type; + void *d; + int c; +{ + unsigned char *p = str_data + 4; + unsigned char *cd = (unsigned char *)d; + + if (c == -1) + c = strlen((char *)cd); + + if (auth_debug_mode) { + printf("%s:%d: [%d] (%d)", + str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY", + str_data[3], + type, c); + printd(d, c); + printf("\r\n"); + } + *p++ = ap->type; + *p++ = ap->way; + *p++ = type; + while (c-- > 0) { + if ((*p++ = *cd++) == IAC) + *p++ = IAC; + } + *p++ = IAC; + *p++ = SE; + if (str_data[3] == TELQUAL_IS) + printsub('>', &str_data[2], p - (&str_data[2])); + return(net_write(str_data, p - str_data)); +} + + int +kerberos4_init(ap, server) + Authenticator *ap; + int server; +{ + FILE *fp; + + if (server) { + str_data[3] = TELQUAL_REPLY; + if ((fp = fopen(KEYFILE, "r")) == NULL) + return(0); + fclose(fp); + } else { + str_data[3] = TELQUAL_IS; + } + return(1); +} + +char dst_realm_buf[REALM_SZ], *dest_realm = NULL; +int dst_realm_sz = REALM_SZ; + + int +kerberos4_send(ap) + Authenticator *ap; +{ + KTEXT_ST auth; +#ifdef ENCRYPTION + Block enckey; +#endif /* ENCRYPTION */ + char instance[INST_SZ]; + char *realm; + char *krb_realmofhost(); + char *krb_get_phost(); + CREDENTIALS cred; + int r; + + printf("[ Trying KERBEROS4 ... ]\n"); + if (!UserNameRequested) { + if (auth_debug_mode) { + printf("Kerberos V4: no user name supplied\r\n"); + } + return(0); + } + + bzero(instance, sizeof(instance)); + + if (realm = krb_get_phost(RemoteHostName)) + strncpy(instance, realm, sizeof(instance)); + + instance[sizeof(instance)-1] = '\0'; + + realm = dest_realm ? dest_realm : krb_realmofhost(RemoteHostName); + + if (!realm) { + printf("Kerberos V4: no realm for %s\r\n", RemoteHostName); + return(0); + } + if (r = krb_mk_req(&auth, KRB_SERVICE_NAME, instance, realm, 0L)) { + printf("mk_req failed: %s\r\n", krb_err_txt[r]); + return(0); + } + if (r = krb_get_cred(KRB_SERVICE_NAME, instance, realm, &cred)) { + printf("get_cred failed: %s\r\n", krb_err_txt[r]); + return(0); + } + if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) { + if (auth_debug_mode) + printf("Not enough room for user name\r\n"); + return(0); + } + if (auth_debug_mode) + printf("Sent %d bytes of authentication data\r\n", auth.length); + if (!Data(ap, KRB_AUTH, (void *)auth.dat, auth.length)) { + if (auth_debug_mode) + printf("Not enough room for authentication data\r\n"); + return(0); + } +#ifdef ENCRYPTION + /* + * If we are doing mutual authentication, get set up to send + * the challenge, and verify it when the response comes back. + */ + if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { + register int i; + + des_key_sched(cred.session, sched); + des_set_random_generator_seed(cred.session); + des_new_random_key(challenge); + des_ecb_encrypt(challenge, session_key, sched, 1); + /* + * Increment the challenge by 1, and encrypt it for + * later comparison. + */ + for (i = 7; i >= 0; --i) { + register int x; + x = (unsigned int)challenge[i] + 1; + challenge[i] = x; /* ignore overflow */ + if (x < 256) /* if no overflow, all done */ + break; + } + des_ecb_encrypt(challenge, challenge, sched, 1); + } +#endif /* ENCRYPTION */ + + if (auth_debug_mode) { + printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length)); + printd(auth.dat, auth.length); + printf("\r\n"); + printf("Sent Kerberos V4 credentials to server\r\n"); + } + return(1); +} + + void +kerberos4_is(ap, data, cnt) + Authenticator *ap; + unsigned char *data; + int cnt; +{ +#ifdef ENCRYPTION + Session_Key skey; + Block datablock; +#endif /* ENCRYPTION */ + char realm[REALM_SZ]; + char instance[INST_SZ]; + int r; + + if (cnt-- < 1) + return; + switch (*data++) { + case KRB_AUTH: + if (krb_get_lrealm(realm, 1) != KSUCCESS) { + Data(ap, KRB_REJECT, (void *)"No local V4 Realm.", -1); + auth_finished(ap, AUTH_REJECT); + if (auth_debug_mode) + printf("No local realm\r\n"); + return; + } + bcopy((void *)data, (void *)auth.dat, auth.length = cnt); + if (auth_debug_mode) { + printf("Got %d bytes of authentication data\r\n", cnt); + printf("CK: %d:", kerberos4_cksum(auth.dat, auth.length)); + printd(auth.dat, auth.length); + printf("\r\n"); + } + instance[0] = '*'; instance[1] = 0; + if (r = krb_rd_req(&auth, KRB_SERVICE_NAME, + instance, 0, &adat, "")) { + if (auth_debug_mode) + printf("Kerberos failed him as %s\r\n", name); + Data(ap, KRB_REJECT, (void *)krb_err_txt[r], -1); + auth_finished(ap, AUTH_REJECT); + return; + } +#ifdef ENCRYPTION + bcopy((void *)adat.session, (void *)session_key, sizeof(Block)); +#endif /* ENCRYPTION */ + krb_kntoln(&adat, name); + + if (UserNameRequested && !kuserok(&adat, UserNameRequested)) + Data(ap, KRB_ACCEPT, (void *)0, 0); + else + Data(ap, KRB_REJECT, + (void *)"user is not authorized", -1); + auth_finished(ap, AUTH_USER); + break; + + case KRB_CHALLENGE: +#ifndef ENCRYPTION + Data(ap, KRB_RESPONSE, (void *)0, 0); +#else /* ENCRYPTION */ + if (!VALIDKEY(session_key)) { + /* + * We don't have a valid session key, so just + * send back a response with an empty session + * key. + */ + Data(ap, KRB_RESPONSE, (void *)0, 0); + break; + } + + des_key_sched(session_key, sched); + bcopy((void *)data, (void *)datablock, sizeof(Block)); + /* + * Take the received encrypted challenge, and encrypt + * it again to get a unique session_key for the + * ENCRYPT option. + */ + des_ecb_encrypt(datablock, session_key, sched, 1); + skey.type = SK_DES; + skey.length = 8; + skey.data = session_key; + encrypt_session_key(&skey, 1); + /* + * Now decrypt the received encrypted challenge, + * increment by one, re-encrypt it and send it back. + */ + des_ecb_encrypt(datablock, challenge, sched, 0); + for (r = 7; r >= 0; r++) { + register int t; + t = (unsigned int)challenge[r] + 1; + challenge[r] = t; /* ignore overflow */ + if (t < 256) /* if no overflow, all done */ + break; + } + des_ecb_encrypt(challenge, challenge, sched, 1); + Data(ap, KRB_RESPONSE, (void *)challenge, sizeof(challenge)); +#endif /* ENCRYPTION */ + break; + + default: + if (auth_debug_mode) + printf("Unknown Kerberos option %d\r\n", data[-1]); + Data(ap, KRB_REJECT, 0, 0); + break; + } +} + + void +kerberos4_reply(ap, data, cnt) + Authenticator *ap; + unsigned char *data; + int cnt; +{ +#ifdef ENCRYPTION + Session_Key skey; +#endif /* ENCRYPTION */ + + if (cnt-- < 1) + return; + switch (*data++) { + case KRB_REJECT: + if (cnt > 0) { + printf("[ Kerberos V4 refuses authentication because %.*s ]\r\n", + cnt, data); + } else + printf("[ Kerberos V4 refuses authentication ]\r\n"); + auth_send_retry(); + return; + case KRB_ACCEPT: + printf("[ Kerberos V4 accepts you ]\n"); + if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { + /* + * Send over the encrypted challenge. + */ +#ifndef ENCRYPTION + Data(ap, KRB_CHALLENGE, (void *)0, 0); +#else /* ENCRYPTION */ + Data(ap, KRB_CHALLENGE, (void *)session_key, + sizeof(session_key)); + des_ecb_encrypt(session_key, session_key, sched, 1); + skey.type = SK_DES; + skey.length = 8; + skey.data = session_key; + encrypt_session_key(&skey, 0); +#endif /* ENCRYPTION */ + return; + } + auth_finished(ap, AUTH_USER); + return; + case KRB_RESPONSE: +#ifdef ENCRYPTION + /* + * Verify that the response to the challenge is correct. + */ + if ((cnt != sizeof(Block)) || + (0 != memcmp((void *)data, (void *)challenge, + sizeof(challenge)))) + { +#endif /* ENCRYPTION */ + printf("[ Kerberos V4 challenge failed!!! ]\r\n"); + auth_send_retry(); + return; +#ifdef ENCRYPTION + } + printf("[ Kerberos V4 challenge successful ]\r\n"); + auth_finished(ap, AUTH_USER); +#endif /* ENCRYPTION */ + break; + default: + if (auth_debug_mode) + printf("Unknown Kerberos option %d\r\n", data[-1]); + return; + } +} + + int +kerberos4_status(ap, name, level) + Authenticator *ap; + char *name; + int level; +{ + if (level < AUTH_USER) + return(level); + + if (UserNameRequested && !kuserok(&adat, UserNameRequested)) { + strcpy(name, UserNameRequested); + return(AUTH_VALID); + } else + return(AUTH_USER); +} + +#define BUMP(buf, len) while (*(buf)) {++(buf), --(len);} +#define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);} + + void +kerberos4_printsub(data, cnt, buf, buflen) + unsigned char *data, *buf; + int cnt, buflen; +{ + char lbuf[32]; + register int i; + + buf[buflen-1] = '\0'; /* make sure its NULL terminated */ + buflen -= 1; + + switch(data[3]) { + case KRB_REJECT: /* Rejected (reason might follow) */ + strncpy((char *)buf, " REJECT ", buflen); + goto common; + + case KRB_ACCEPT: /* Accepted (name might follow) */ + strncpy((char *)buf, " ACCEPT ", buflen); + common: + BUMP(buf, buflen); + if (cnt <= 4) + break; + ADDC(buf, buflen, '"'); + for (i = 4; i < cnt; i++) + ADDC(buf, buflen, data[i]); + ADDC(buf, buflen, '"'); + ADDC(buf, buflen, '\0'); + break; + + case KRB_AUTH: /* Authentication data follows */ + strncpy((char *)buf, " AUTH", buflen); + goto common2; + + case KRB_CHALLENGE: + strncpy((char *)buf, " CHALLENGE", buflen); + goto common2; + + case KRB_RESPONSE: + strncpy((char *)buf, " RESPONSE", buflen); + goto common2; + + default: + sprintf(lbuf, " %d (unknown)", data[3]); + strncpy((char *)buf, lbuf, buflen); + common2: + BUMP(buf, buflen); + for (i = 4; i < cnt; i++) { + sprintf(lbuf, " %d", data[i]); + strncpy((char *)buf, lbuf, buflen); + BUMP(buf, buflen); + } + break; + } +} + + int +kerberos4_cksum(d, n) + unsigned char *d; + int n; +{ + int ck = 0; + + /* + * A comment is probably needed here for those not + * well versed in the "C" language. Yes, this is + * supposed to be a "switch" with the body of the + * "switch" being a "while" statement. The whole + * purpose of the switch is to allow us to jump into + * the middle of the while() loop, and then not have + * to do any more switch()s. + * + * Some compilers will spit out a warning message + * about the loop not being entered at the top. + */ + switch (n&03) + while (n > 0) { + case 0: + ck ^= (int)*d++ << 24; + --n; + case 3: + ck ^= (int)*d++ << 16; + --n; + case 2: + ck ^= (int)*d++ << 8; + --n; + case 1: + ck ^= (int)*d++; + --n; + } + return(ck); +} +#endif + +#ifdef notdef + +prkey(msg, key) + char *msg; + unsigned char *key; +{ + register int i; + printf("%s:", msg); + for (i = 0; i < 8; i++) + printf(" %3d", key[i]); + printf("\r\n"); +} +#endif |
