1/*-
2 * Copyright (c) 1992, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by the University of
16 *	California, Berkeley and its contributors.
17 * 4. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/cdefs.h>
35
36__FBSDID("$FreeBSD: src/contrib/telnet/libtelnet/rsaencpwd.c,v 1.3 2001/11/30 21:06:34 markm Exp $");
37
38
39#ifdef	RSA_ENCPWD
40/*
41 * COPYRIGHT (C) 1990 DIGITAL EQUIPMENT CORPORATION
42 * ALL RIGHTS RESERVED
43 *
44 * "Digital Equipment Corporation authorizes the reproduction,
45 * distribution and modification of this software subject to the following
46 * restrictions:
47 *
48 * 1.  Any partial or whole copy of this software, or any modification
49 * thereof, must include this copyright notice in its entirety.
50 *
51 * 2.  This software is supplied "as is" with no warranty of any kind,
52 * expressed or implied, for any purpose, including any warranty of fitness
53 * or merchantibility.  DIGITAL assumes no responsibility for the use or
54 * reliability of this software, nor promises to provide any form of
55 * support for it on any basis.
56 *
57 * 3.  Distribution of this software is authorized only if no profit or
58 * remuneration of any kind is received in exchange for such distribution.
59 *
60 * 4.  This software produces public key authentication certificates
61 * bearing an expiration date established by DIGITAL and RSA Data
62 * Security, Inc.  It may cease to generate certificates after the expiration
63 * date.  Any modification of this software that changes or defeats
64 * the expiration date or its effect is unauthorized.
65 *
66 * 5.  Software that will renew or extend the expiration date of
67 * authentication certificates produced by this software may be obtained
68 * from RSA Data Security, Inc., 10 Twin Dolphin Drive, Redwood City, CA
69 * 94065, (415)595-8782, or from DIGITAL"
70 *
71 */
72
73#include <sys/types.h>
74#include <arpa/telnet.h>
75#include <pwd.h>
76#include <stdio.h>
77#include <stdlib.h>
78#include <string.h>
79
80#include "encrypt.h"
81#include "auth.h"
82#include "misc.h"
83#include "cdc.h"
84
85extern auth_debug_mode;
86
87static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
88			  		AUTHTYPE_RSA_ENCPWD, };
89static unsigned char str_name[1024] = { IAC, SB, TELOPT_AUTHENTICATION,
90					TELQUAL_NAME, };
91
92#define	RSA_ENCPWD_AUTH	0	/* Authentication data follows */
93#define	RSA_ENCPWD_REJECT	1	/* Rejected (reason might follow) */
94#define RSA_ENCPWD_ACCEPT	2	/* Accepted */
95#define	RSA_ENCPWD_CHALLENGEKEY	3	/* Challenge and public key */
96
97#define NAME_SZ   40
98#define CHAL_SZ   20
99#define PWD_SZ    40
100
101static	KTEXT_ST auth;
102static	char name[NAME_SZ];
103static	char user_passwd[PWD_SZ];
104static  char key_file[2*NAME_SZ];
105static  char lhostname[NAME_SZ];
106static char  challenge[CHAL_SZ];
107static int   challenge_len;
108
109	static int
110Data(ap, type, d, c)
111	Authenticator *ap;
112	int type;
113	void *d;
114	int c;
115{
116	unsigned char *p = str_data + 4;
117	unsigned char *cd = (unsigned char *)d;
118
119	if (c == -1)
120		c = strlen((char *)cd);
121
122	if (0) {
123		printf("%s:%d: [%d] (%d)",
124			str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
125			str_data[3],
126			type, c);
127		printd(d, c);
128		printf("\r\n");
129	}
130	*p++ = ap->type;
131	*p++ = ap->way;
132	if (type != NULL) *p++ = type;
133	while (c-- > 0) {
134		if ((*p++ = *cd++) == IAC)
135			*p++ = IAC;
136	}
137	*p++ = IAC;
138	*p++ = SE;
139	if (str_data[3] == TELQUAL_IS)
140		printsub('>', &str_data[2], p - (&str_data[2]));
141	return(net_write(str_data, p - str_data));
142}
143
144	int
145rsaencpwd_init(ap, server)
146	Authenticator *ap;
147	int server;
148{
149	char  *cp;
150	FILE  *fp;
151
152	if (server) {
153		str_data[3] = TELQUAL_REPLY;
154		memset(key_file, 0, sizeof(key_file));
155		gethostname(lhostname, sizeof(lhostname));
156		if ((cp = strchr(lhostname, '.')) != 0)  *cp = '\0';
157		strcpy(key_file, "/etc/.");
158		strcat(key_file, lhostname);
159		strcat(key_file, "_privkey");
160		if ((fp=fopen(key_file, "r"))==NULL) return(0);
161		fclose(fp);
162	} else {
163		str_data[3] = TELQUAL_IS;
164	}
165	return(1);
166}
167
168	int
169rsaencpwd_send(ap)
170	Authenticator *ap;
171{
172
173	printf("[ Trying RSAENCPWD ... ]\n");
174	if (!UserNameRequested) {
175		return(0);
176	}
177	if (!auth_sendname(UserNameRequested, strlen(UserNameRequested))) {
178		return(0);
179	}
180	if (!Data(ap, NULL, (void *)NULL, 0)) {
181		return(0);
182	}
183
184
185	return(1);
186}
187
188	void
189rsaencpwd_is(ap, data, cnt)
190	Authenticator *ap;
191	unsigned char *data;
192	int cnt;
193{
194	Session_Key skey;
195	Block datablock;
196	char  r_passwd[PWD_SZ], r_user[NAME_SZ];
197	char  *cp, key[160];
198	char  chalkey[160], *ptr;
199	FILE  *fp;
200	int r, i, j, chalkey_len, len;
201	time_t now;
202
203	cnt--;
204	switch (*data++) {
205	case RSA_ENCPWD_AUTH:
206		memmove((void *)auth.dat, (void *)data, auth.length = cnt);
207
208		if ((fp=fopen(key_file, "r"))==NULL) {
209		  Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
210		  auth_finished(ap, AUTH_REJECT);
211		  return;
212		}
213		/*
214		 *  get privkey
215		 */
216		fscanf(fp, "%x;", &len);
217		for (i=0;i<len;i++) {
218		  j = getc(fp);  key[i]=j;
219		}
220		fclose(fp);
221
222		r = accept_rsa_encpwd(&auth, key, challenge,
223				      challenge_len, r_passwd);
224		if (r < 0) {
225		  Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
226		  auth_finished(ap, AUTH_REJECT);
227		  return;
228		}
229		auth_encrypt_userpwd(r_passwd);
230		if (rsaencpwd_passwdok(UserNameRequested, UserPassword) == 0) {
231		  /*
232		   *  illegal username and password
233		   */
234		  Data(ap, RSA_ENCPWD_REJECT, (void *)"Illegal password", -1);
235		  auth_finished(ap, AUTH_REJECT);
236		  return;
237		}
238
239		Data(ap, RSA_ENCPWD_ACCEPT, (void *)0, 0);
240		auth_finished(ap, AUTH_USER);
241		break;
242
243
244	case IAC:
245
246		/*
247		 * If we are doing mutual authentication, get set up to send
248		 * the challenge, and verify it when the response comes back.
249		 */
250		if ((ap->way & AUTH_HOW_MASK) == AUTH_HOW_ONE_WAY) {
251		  register int i;
252
253
254		  time(&now);
255		  if ((now % 2) == 0) {
256		    sprintf(challenge, "%x", now);
257		    challenge_len = strlen(challenge);
258		  } else {
259		    strcpy(challenge, "randchal");
260		    challenge_len = 8;
261		  }
262
263		  if ((fp=fopen(key_file, "r"))==NULL) {
264		    Data(ap, RSA_ENCPWD_REJECT, (void *)"Auth failed", -1);
265		    auth_finished(ap, AUTH_REJECT);
266		    return;
267		  }
268		  /*
269		   *  skip privkey
270		   */
271		  fscanf(fp, "%x;", &len);
272		  for (i=0;i<len;i++) {
273		    j = getc(fp);
274		  }
275		  /*
276		   * get pubkey
277		   */
278		  fscanf(fp, "%x;", &len);
279		  for (i=0;i<len;i++) {
280		    j = getc(fp);  key[i]=j;
281		  }
282		  fclose(fp);
283		  chalkey[0] = 0x30;
284		  ptr = (char *) &chalkey[1];
285		  chalkey_len = 1+NumEncodeLengthOctets(i)+i+1+NumEncodeLengthOctets(challenge_len)+challenge_len;
286		  EncodeLength(ptr, chalkey_len);
287		  ptr +=NumEncodeLengthOctets(chalkey_len);
288		  *ptr++ = 0x04;  /* OCTET STRING */
289		  *ptr++ = challenge_len;
290		  memmove(ptr, challenge, challenge_len);
291		  ptr += challenge_len;
292		  *ptr++ = 0x04;  /* OCTET STRING */
293		  EncodeLength(ptr, i);
294		  ptr += NumEncodeLengthOctets(i);
295		  memmove(ptr, key, i);
296		  chalkey_len = 1+NumEncodeLengthOctets(chalkey_len)+chalkey_len;
297		  Data(ap, RSA_ENCPWD_CHALLENGEKEY, (void *)chalkey, chalkey_len);
298		}
299		break;
300
301	default:
302		Data(ap, RSA_ENCPWD_REJECT, 0, 0);
303		break;
304	}
305}
306
307
308	void
309rsaencpwd_reply(ap, data, cnt)
310	Authenticator *ap;
311	unsigned char *data;
312	int cnt;
313{
314	Session_Key skey;
315	KTEXT_ST token;
316	Block enckey;
317	int r, pubkey_len;
318	char	randchal[CHAL_SZ], *cp;
319	char	chalkey[160], pubkey[128], *ptr;
320
321	if (cnt-- < 1)
322		return;
323	switch (*data++) {
324	case RSA_ENCPWD_REJECT:
325		if (cnt > 0) {
326			printf("[ RSA_ENCPWD refuses authentication because %.*s ]\r\n",
327				cnt, data);
328		} else
329			printf("[ RSA_ENCPWD refuses authentication ]\r\n");
330		auth_send_retry();
331		return;
332	case RSA_ENCPWD_ACCEPT:
333		printf("[ RSA_ENCPWD accepts you ]\n");
334		auth_finished(ap, AUTH_USER);
335		return;
336	case RSA_ENCPWD_CHALLENGEKEY:
337		/*
338		 * Verify that the response to the challenge is correct.
339		 */
340
341		memmove((void *)chalkey, (void *)data, cnt);
342		ptr = (char *) &chalkey[0];
343		ptr += DecodeHeaderLength(chalkey);
344		if (*ptr != 0x04) {
345		  return;
346		}
347		*ptr++;
348		challenge_len = DecodeValueLength(ptr);
349		ptr += NumEncodeLengthOctets(challenge_len);
350		memmove(challenge, ptr, challenge_len);
351		ptr += challenge_len;
352		if (*ptr != 0x04) {
353		  return;
354		}
355		*ptr++;
356		pubkey_len = DecodeValueLength(ptr);
357		ptr += NumEncodeLengthOctets(pubkey_len);
358		memmove(pubkey, ptr, pubkey_len);
359		memset(user_passwd, 0, sizeof(user_passwd));
360		local_des_read_pw_string(user_passwd, sizeof(user_passwd)-1, "Password: ", 0);
361		UserPassword = user_passwd;
362		Challenge = challenge;
363		r = init_rsa_encpwd(&token, user_passwd, challenge, challenge_len, pubkey);
364		if (r < 0) {
365		  token.length = 1;
366		}
367
368		if (!Data(ap, RSA_ENCPWD_AUTH, (void *)token.dat, token.length)) {
369		  return;
370		}
371
372		break;
373
374	default:
375		return;
376	}
377}
378
379	int
380rsaencpwd_status(ap, name, level)
381	Authenticator *ap;
382	char *name;
383	int level;
384{
385
386	if (level < AUTH_USER)
387		return(level);
388
389	if (UserNameRequested && rsaencpwd_passwdok(UserNameRequested, UserPassword)) {
390		strcpy(name, UserNameRequested);
391		return(AUTH_VALID);
392	} else {
393		return(AUTH_USER);
394	}
395}
396
397#define	BUMP(buf, len)		while (*(buf)) {++(buf), --(len);}
398#define	ADDC(buf, len, c)	if ((len) > 0) {*(buf)++ = (c); --(len);}
399
400	void
401rsaencpwd_printsub(data, cnt, buf, buflen)
402	unsigned char *data, *buf;
403	int cnt, buflen;
404{
405	char lbuf[32];
406	register int i;
407
408	buf[buflen-1] = '\0';		/* make sure its NULL terminated */
409	buflen -= 1;
410
411	switch(data[3]) {
412	case RSA_ENCPWD_REJECT:	/* Rejected (reason might follow) */
413		strncpy((char *)buf, " REJECT ", buflen);
414		goto common;
415
416	case RSA_ENCPWD_ACCEPT:	/* Accepted (name might follow) */
417		strncpy((char *)buf, " ACCEPT ", buflen);
418	common:
419		BUMP(buf, buflen);
420		if (cnt <= 4)
421			break;
422		ADDC(buf, buflen, '"');
423		for (i = 4; i < cnt; i++)
424			ADDC(buf, buflen, data[i]);
425		ADDC(buf, buflen, '"');
426		ADDC(buf, buflen, '\0');
427		break;
428
429	case RSA_ENCPWD_AUTH:		/* Authentication data follows */
430		strncpy((char *)buf, " AUTH", buflen);
431		goto common2;
432
433	case RSA_ENCPWD_CHALLENGEKEY:
434		strncpy((char *)buf, " CHALLENGEKEY", buflen);
435		goto common2;
436
437	default:
438		sprintf(lbuf, " %d (unknown)", data[3]);
439		strncpy((char *)buf, lbuf, buflen);
440	common2:
441		BUMP(buf, buflen);
442		for (i = 4; i < cnt; i++) {
443			sprintf(lbuf, " %d", data[i]);
444			strncpy((char *)buf, lbuf, buflen);
445			BUMP(buf, buflen);
446		}
447		break;
448	}
449}
450
451int rsaencpwd_passwdok(name, passwd)
452char *name, *passwd;
453{
454  char *crypt();
455  char *salt, *p;
456  struct passwd *pwd;
457  int   passwdok_status = 0;
458
459  if (pwd = getpwnam(name))
460    salt = pwd->pw_passwd;
461  else salt = "xx";
462
463  p = crypt(passwd, salt);
464
465  if (pwd && !strcmp(p, pwd->pw_passwd)) {
466    passwdok_status = 1;
467  } else passwdok_status = 0;
468  return(passwdok_status);
469}
470
471#endif
472