/* * $Source: /home/ncvs/src/lib/libtelnet/kerberos5.c,v $ * $Author: rgrimes $ * $Id: kerberos5.c,v 1.1.1.1 1994/05/27 05:00:20 rgrimes Exp $ */ #if !defined(lint) && !defined(SABER) static #ifdef __STDC__ const #endif char rcsid_kerberos5_c[] = "$Id: kerberos5.c,v 1.1.1.1 1994/05/27 05:00:20 rgrimes Exp $"; #endif /* lint */ /*- * 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[] = "@(#)kerberos5.c 8.2 (Berkeley) 12/15/93"; #endif /* not lint */ /* * Copyright (C) 1990 by the Massachusetts Institute of Technology * * Export of this software from the United States of America may * 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 KRB5 #include #include #include #include #include #include #include #include #include #include /* kerberos 5 include files (ext-proto.h) will get an appropriate stdlib.h and string.h/strings.h */ #include "encrypt.h" #include "auth.h" #include "misc.h" extern auth_debug_mode; #ifdef FORWARD int forward_flags = 0; /* Flags get set in telnet/main.c on -f and -F */ /* These values need to be the same as those defined in telnet/main.c. */ /* Either define them in both places, or put in some common header file. */ #define OPTS_FORWARD_CREDS 0x00000002 #define OPTS_FORWARDABLE_CREDS 0x00000001 void kerberos5_forward(); #endif /* FORWARD */ static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0, AUTHTYPE_KERBEROS_V5, }; /*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_RESPONSE 3 /* Response for mutual auth. */ #ifdef FORWARD #define KRB_FORWARD 4 /* Forwarded credentials follow */ #define KRB_FORWARD_ACCEPT 5 /* Forwarded credentials accepted */ #define KRB_FORWARD_REJECT 6 /* Forwarded credentials rejected */ #endif /* FORWARD */ static krb5_data auth; /* telnetd gets session key from here */ static krb5_tkt_authent *authdat = NULL; /* telnet matches the AP_REQ and AP_REP with this */ static krb5_authenticator authenticator; /* some compilers can't hack void *, so we use the Kerberos krb5_pointer, which is either void * or char *, depending on the compiler. */ #define Voidptr krb5_pointer Block session_key; static int Data(ap, type, d, c) Authenticator *ap; int type; Voidptr 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 kerberos5_init(ap, server) Authenticator *ap; int server; { if (server) str_data[3] = TELQUAL_REPLY; else str_data[3] = TELQUAL_IS; krb5_init_ets(); return(1); } int kerberos5_send(ap) Authenticator *ap; { char **realms; char *name; char *p1, *p2; krb5_checksum ksum; krb5_octet sum[CRC32_CKSUM_LENGTH]; krb5_principal server; krb5_error_code r; krb5_ccache ccache; krb5_creds creds; /* telnet gets session key from here */ extern krb5_flags krb5_kdc_default_options; int ap_opts; #ifdef ENCRYPTION krb5_keyblock *newkey = 0; #endif /* ENCRYPTION */ ksum.checksum_type = CKSUMTYPE_CRC32; ksum.contents = sum; ksum.length = sizeof(sum); bzero((Voidptr )sum, sizeof(sum)); if (!UserNameRequested) { if (auth_debug_mode) { printf("Kerberos V5: no user name supplied\r\n"); } return(0); } if (r = krb5_cc_default(&ccache)) { if (auth_debug_mode) { printf("Kerberos V5: could not get default ccache\r\n"); } return(0); } if ((name = malloc(strlen(RemoteHostName)+1)) == NULL) { if (auth_debug_mode) printf("Out of memory for hostname in Kerberos V5\r\n"); return(0); } if (r = krb5_get_host_realm(RemoteHostName, &realms)) { if (auth_debug_mode) printf("Kerberos V5: no realm for %s\r\n", RemoteHostName); free(name); return(0); } p1 = RemoteHostName; p2 = name; while (*p2 = *p1++) { if (isupper(*p2)) *p2 |= 040; ++p2; } if (r = krb5_build_principal_ext(&server, strlen(realms[0]), realms[0], 4, "host", p2 - name, name, 0)) { if (auth_debug_mode) { printf("Kerberos V5: failure setting up principal (%s)\r\n", error_message(r)); } free(name); krb5_free_host_realm(realms); return(0); } bzero((char *)&creds, sizeof(creds)); creds.server = server; if (r = krb5_cc_get_principal(ccache, &creds.client)) { if (auth_debug_mode) { printf("Kerberos V5: failure on principal (%s)\r\n", error_message(r)); } free(name); krb5_free_principal(server); krb5_free_host_realm(realms); return(0); } if (r = krb5_get_credentials(krb5_kdc_default_options, ccache, &creds)) { if (auth_debug_mode) { printf("Kerberos V5: failure on credentials(%d)\r\n",r); } free(name); krb5_free_host_realm(realms); krb5_free_principal(server); return(0); } if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) ap_opts = AP_OPTS_MUTUAL_REQUIRED; else ap_opts = 0; r = krb5_mk_req_extended(ap_opts, &ksum, krb5_kdc_default_options, 0, #ifdef ENCRYPTION &newkey, #else /* ENCRYPTION */ 0, #endif /* ENCRYPTION */ ccache, &creds, &authenticator, &auth); /* don't let the key get freed if we clean up the authenticator */ authenticator.subkey = 0; free(name); krb5_free_host_realm(realms); krb5_free_principal(server); #ifdef ENCRYPTION if (newkey) { /* keep the key in our private storage, but don't use it yet---see kerberos5_reply() below */ if (newkey->keytype != KEYTYPE_DES) { if (creds.keyblock.keytype == KEYTYPE_DES) /* use the session key in credentials instead */ memcpy((char *)session_key, (char *)creds.keyblock.contents, sizeof(Block)); else /* XXX ? */; } else { memcpy((char *)session_key, (char *)newkey->contents, sizeof(Block)); } krb5_free_keyblock(newkey); } #endif /* ENCRYPTION */ if (r) { if (auth_debug_mode) { printf("Kerberos V5: mk_req failed (%s)\r\n", error_message(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 (!Data(ap, KRB_AUTH, auth.data, auth.length)) { if (auth_debug_mode) printf("Not enough room for authentication data\r\n"); return(0); } if (auth_debug_mode) { printf("Sent Kerberos V5 credentials to server\r\n"); } return(1); } void kerberos5_is(ap, data, cnt) Authenticator *ap; unsigned char *data; int cnt; { int r; struct hostent *hp; char *p1, *p2; static char *realm = NULL; krb5_principal server; krb5_ap_rep_enc_part reply; krb5_data outbuf; #ifdef ENCRYPTION Session_Key skey; #endif /* ENCRYPTION */ char *name; char *getenv(); krb5_data inbuf; if (cnt-- < 1) return; switch (*data++) { case KRB_AUTH: auth.data = (char *)data; auth.length = cnt; if (!(hp = gethostbyname(LocalHostName))) { if (auth_debug_mode) printf("Cannot resolve local host name\r\n"); Data(ap, KRB_REJECT, "Unknown local hostname.", -1); auth_finished(ap, AUTH_REJECT); return; } if (!realm && (krb5_get_default_realm(&realm))) { if (auth_debug_mode) printf("Could not get default realm\r\n"); Data(ap, KRB_REJECT, "Could not get default realm.", -1); auth_finished(ap, AUTH_REJECT); return; } if ((name = malloc(strlen(hp->h_name)+1)) == NULL) { if (auth_debug_mode) printf("Out of memory for hostname in Kerberos V5\r\n"); Data(ap, KRB_REJECT, "Out of memory.", -1); auth_finished(ap, AUTH_REJECT); return; } p1 = hp->h_name; p2 = name; while (*p2 = *p1++) { if (isupper(*p2)) *p2 |= 040; ++p2; } if (authdat) krb5_free_tkt_authent(authdat); r = krb5_build_principal_ext(&server, strlen(realm), realm, 4, "host", p2 - name, name, 0); if (!r) { r = krb5_rd_req_simple(&auth, server, 0, &authdat); krb5_free_principal(server); } if (r) { char errbuf[128]; errout: authdat = 0; (void) strcpy(errbuf, "Read req failed: "); (void) strcat(errbuf, error_message(r)); Data(ap, KRB_REJECT, errbuf, -1); if (auth_debug_mode) printf("%s\r\n", errbuf); return; } free(name); if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { /* do ap_rep stuff here */ reply.ctime = authdat->authenticator->ctime; reply.cusec = authdat->authenticator->cusec; reply.subkey = 0; /* use the one he gave us, so don't need to return one here */ reply.seq_number = 0; /* we don't do seq #'s. */ if (r = krb5_mk_rep(&reply, authdat->authenticator->subkey ? authdat->authenticator->subkey : authdat->ticket->enc_part2->session, &outbuf)) { goto errout; } Data(ap, KRB_RESPONSE, outbuf.data, outbuf.length); } if (krb5_unparse_name(authdat->ticket->enc_part2 ->client, &name)) name = 0; Data(ap, KRB_ACCEPT, name, name ? -1 : 0); if (auth_debug_mode) { printf("Kerberos5 identifies him as ``%s''\r\n", name ? name : ""); } auth_finished(ap, AUTH_USER); free(name); if (authdat->authenticator->subkey && authdat->authenticator->subkey->keytype == KEYTYPE_DES) { bcopy((Voidptr )authdat->authenticator->subkey->contents, (Voidptr )session_key, sizeof(Block)); } else if (authdat->ticket->enc_part2->session->keytype == KEYTYPE_DES) { bcopy((Voidptr )authdat->ticket->enc_part2->session->contents, (Voidptr )session_key, sizeof(Block)); } else break; #ifdef ENCRYPTION skey.type = SK_DES; skey.length = 8; skey.data = session_key; encrypt_session_key(&skey, 1); #endif /* ENCRYPTION */ break; #ifdef FORWARD case KRB_FORWARD: inbuf.data = (char *)data; inbuf.length = cnt; if (r = rd_and_store_for_creds(&inbuf, authdat->ticket, UserNameRequested)) { char errbuf[128]; (void) strcpy(errbuf, "Read forwarded creds failed: "); (void) strcat(errbuf, error_message(r)); Data(ap, KRB_FORWARD_REJECT, errbuf, -1); if (auth_debug_mode) printf("Could not read forwarded credentials\r\n"); } else Data(ap, KRB_FORWARD_ACCEPT, 0, 0); if (auth_debug_mode) printf("Forwarded credentials obtained\r\n"); break; #endif /* FORWARD */ default: if (auth_debug_mode) printf("Unknown Kerberos option %d\r\n", data[-1]); Data(ap, KRB_REJECT, 0, 0); break; } } void kerberos5_reply(ap, data, cnt) Authenticator *ap; unsigned char *data; int cnt; { Session_Key skey; static int mutual_complete = 0; if (cnt-- < 1) return; switch (*data++) { case KRB_REJECT: if (cnt > 0) { printf("[ Kerberos V5 refuses authentication because %.*s ]\r\n", cnt, data); } else printf("[ Kerberos V5 refuses authentication ]\r\n"); auth_send_retry(); return; case KRB_ACCEPT: if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL && !mutual_complete) { printf("[ Kerberos V5 accepted you, but didn't provide mutual authentication! ]\n"); auth_send_retry(); return; } if (cnt) printf("[ Kerberos V5 accepts you as ``%.*s'' ]\n", cnt, data); else printf("[ Kerberos V5 accepts you ]\n"); auth_finished(ap, AUTH_USER); #ifdef FORWARD if (forward_flags & OPTS_FORWARD_CREDS) kerberos5_forward(ap); #endif /* FORWARD */ break; case KRB_RESPONSE: if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_MUTUAL) { /* the rest of the reply should contain a krb_ap_rep */ krb5_ap_rep_enc_part *reply; krb5_data inbuf; krb5_error_code r; krb5_keyblock tmpkey; inbuf.length = cnt; inbuf.data = (char *)data; tmpkey.keytype = KEYTYPE_DES; tmpkey.contents = session_key; tmpkey.length = sizeof(Block); if (r = krb5_rd_rep(&inbuf, &tmpkey, &reply)) { printf("[ Mutual authentication failed: %s ]\n", error_message(r)); auth_send_retry(); return; } if (reply->ctime != authenticator.ctime || reply->cusec != authenticator.cusec) { printf("[ Mutual authentication failed (mismatched KRB_AP_REP) ]\n"); auth_send_retry(); return; } krb5_free_ap_rep_enc_part(reply); #ifdef ENCRYPTION skey.type = SK_DES; skey.length = 8; skey.data = session_key; encrypt_session_key(&skey, 0); #endif /* ENCRYPTION */ mutual_complete = 1; } return; #ifdef FORWARD case KRB_FORWARD_ACCEPT: printf("[ Kerberos V5 accepted forwarded credentials ]\n"); return; case KRB_FORWARD_REJECT: printf("[ Kerberos V5 refuses forwarded credentials because %.*s ]\r\n", cnt, data); return; #endif /* FORWARD */ default: if (auth_debug_mode) printf("Unknown Kerberos option %d\r\n", data[-1]); return; } } int kerberos5_status(ap, name, level) Authenticator *ap; char *name; int level; { if (level < AUTH_USER) return(level); if (UserNameRequested && krb5_kuserok(authdat->ticket->enc_part2->client, 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 kerberos5_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_RESPONSE: strncpy((char *)buf, " RESPONSE", buflen); goto common2; #ifdef FORWARD case KRB_FORWARD: /* Forwarded credentials follow */ strncpy((char *)buf, " FORWARD", buflen); goto common2; case KRB_FORWARD_ACCEPT: /* Forwarded credentials accepted */ strncpy((char *)buf, " FORWARD_ACCEPT", buflen); goto common2; case KRB_FORWARD_REJECT: /* Forwarded credentials rejected */ /* (reason might follow) */ strncpy((char *)buf, " FORWARD_REJECT", buflen); goto common2; #endif /* FORWARD */ 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; } } #ifdef FORWARD void kerberos5_forward(ap) Authenticator *ap; { struct hostent *hp; krb5_creds *local_creds; krb5_error_code r; krb5_data forw_creds; extern krb5_cksumtype krb5_kdc_req_sumtype; krb5_ccache ccache; int i; if (!(local_creds = (krb5_creds *) calloc(1, sizeof(*local_creds)))) { if (auth_debug_mode) printf("Kerberos V5: could not allocate memory for credentials\r\n"); return; } if (r = krb5_sname_to_principal(RemoteHostName, "host", 1, &local_creds->server)) { if (auth_debug_mode) printf("Kerberos V5: could not build server name - %s\r\n", error_message(r)); krb5_free_creds(local_creds); return; } if (r = krb5_cc_default(&ccache)) { if (auth_debug_mode) printf("Kerberos V5: could not get default ccache - %s\r\n", error_message(r)); krb5_free_creds(local_creds); return; } if (r = krb5_cc_get_principal(ccache, &local_creds->client)) { if (auth_debug_mode) printf("Kerberos V5: could not get default principal - %s\r\n", error_message(r)); krb5_free_creds(local_creds); return; } /* Get ticket from credentials cache */ if (r = krb5_get_credentials(KRB5_GC_CACHED, ccache, local_creds)) { if (auth_debug_mode) printf("Kerberos V5: could not obtain credentials - %s\r\n", error_message(r)); krb5_free_creds(local_creds); return; } if (r = get_for_creds(ETYPE_DES_CBC_CRC, krb5_kdc_req_sumtype, RemoteHostName, local_creds->client, &local_creds->keyblock, forward_flags & OPTS_FORWARDABLE_CREDS, &forw_creds)) { if (auth_debug_mode) printf("Kerberos V5: error getting forwarded creds - %s\r\n", error_message(r)); krb5_free_creds(local_creds); return; } /* Send forwarded credentials */ if (!Data(ap, KRB_FORWARD, forw_creds.data, forw_creds.length)) { if (auth_debug_mode) printf("Not enough room for authentication data\r\n"); } else { if (auth_debug_mode) printf("Forwarded local Kerberos V5 credentials to server\r\n"); } krb5_free_creds(local_creds); } #endif /* FORWARD */ #endif /* KRB5 */