2 * Copyright (c) 1991, 1993
3 * Dave Safford. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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. Neither the name of the University nor the names of its contributors
14 * may be used to endorse or promote products derived from this software
15 * without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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29 * $FreeBSD: src/crypto/telnet/libtelnet/sra.c,v 1.1.2.7 2002/05/16 08:46:49 markm Exp $
34 #include <sys/types.h>
35 #include <arpa/telnet.h>
44 #include <security/pam_appl.h>
54 char pka[HEXKEYBYTES+1], ska[HEXKEYBYTES+1], pkb[HEXKEYBYTES+1];
55 char *user, *pass, *xuser, *xpass;
61 extern int auth_debug_mode;
64 static int sra_valid = 0;
65 static int passwd_sent = 0;
67 static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
72 #define SRA_CONTINUE 2
77 static int check_user(char *, char *);
79 /* support routine to send out authentication message */
81 Data(Authenticator *ap, int type, void *d, int c)
83 unsigned char *p = str_data + 4;
84 unsigned char *cd = (unsigned char *)d;
87 c = strlen((char *)cd);
89 if (auth_debug_mode) {
90 printf("%s:%d: [%d] (%d)",
91 str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
101 if ((*p++ = *cd++) == IAC)
106 if (str_data[3] == TELQUAL_IS)
107 printsub('>', &str_data[2], p - (&str_data[2]));
108 return(net_write(str_data, p - str_data));
112 sra_init(Authenticator *ap __unused, int server)
115 str_data[3] = TELQUAL_REPLY;
117 str_data[3] = TELQUAL_IS;
119 user = (char *)malloc(256);
120 xuser = (char *)malloc(513);
121 pass = (char *)malloc(PASS_SIZE);
122 xpass = (char *)malloc(513);
124 if (user == NULL || xuser == NULL || pass == NULL || xpass ==
126 return 0; /* malloc failed */
134 /* client received a go-ahead for sra */
136 sra_send(Authenticator *ap)
141 printf("Sent PKA to server.\r\n" );
142 printf("Trying SRA secure login:\r\n");
143 if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
145 printf("Not enough room for authentication data\r\n");
152 /* server received an IS -- could be SRA KEY, USER, or PASS */
154 sra_is(Authenticator *ap, unsigned char *data, int cnt)
164 if (cnt < HEXKEYBYTES) {
165 Data(ap, SRA_REJECT, (void *)0, 0);
166 auth_finished(ap, AUTH_USER);
167 if (auth_debug_mode) {
168 printf("SRA user rejected for bad PKB\r\n");
173 printf("Sent pka\r\n");
174 if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
176 printf("Not enough room\r\n");
179 memcpy(pkb,data,HEXKEYBYTES);
180 pkb[HEXKEYBYTES] = '\0';
181 common_key(ska,pkb,&ik,&ck);
186 if (cnt > 512) /* Attempted buffer overflow */
188 memcpy(xuser,data,cnt);
190 pk_decode(xuser,user,&ck);
191 auth_encrypt_user(user);
192 Data(ap, SRA_CONTINUE, (void *)0, 0);
197 if (cnt > 512) /* Attempted buffer overflow */
200 memcpy(xpass,data,cnt);
202 pk_decode(xpass,pass,&ck);
204 /* check user's password */
205 valid = check_user(user,pass);
208 Data(ap, SRA_ACCEPT, (void *)0, 0);
212 encrypt_session_key(&skey, 1);
215 auth_finished(ap, AUTH_VALID);
216 if (auth_debug_mode) {
217 printf("SRA user accepted\r\n");
221 Data(ap, SRA_CONTINUE, (void *)0, 0);
223 Data(ap, SRA_REJECT, (void *)0, 0);
225 auth_finished(ap, AUTH_REJECT);
227 if (auth_debug_mode) {
228 printf("SRA user failed\r\n");
235 printf("Unknown SRA option %d\r\n", data[-1]);
238 Data(ap, SRA_REJECT, 0, 0);
240 auth_finished(ap, AUTH_REJECT);
243 /* client received REPLY -- could be SRA KEY, CONTINUE, ACCEPT, or REJECT */
245 sra_reply(Authenticator *ap, unsigned char *data, int cnt)
247 char uprompt[256],tuser[256];
256 /* calculate common key */
257 if (cnt < HEXKEYBYTES) {
258 if (auth_debug_mode) {
259 printf("SRA user rejected for bad PKB\r\n");
263 memcpy(pkb,data,HEXKEYBYTES);
264 pkb[HEXKEYBYTES] = '\0';
266 common_key(ska,pkb,&ik,&ck);
271 memset(tuser,0,sizeof(tuser));
272 sprintf(uprompt,"User (%s): ",UserNameRequested);
273 telnet_gets(uprompt,tuser,255,1);
274 if (tuser[0] == '\n' || tuser[0] == '\r' )
275 strcpy(user,UserNameRequested);
277 /* telnet_gets leaves the newline on */
278 for(i=0;i<sizeof(tuser);i++) {
279 if (tuser[i] == '\n') {
286 pk_encode(user,xuser,&ck);
290 printf("Sent KAB(U)\r\n");
291 if (!Data(ap, SRA_USER, xuser, strlen(xuser))) {
293 printf("Not enough room\r\n");
301 printf("[ SRA login failed ]\r\n");
304 /* encode password */
305 memset(pass,0,PASS_SIZE);
306 telnet_gets("Password: ",pass,PASS_SIZE-1,0);
307 pk_encode(pass,xpass,&ck);
310 printf("Sent KAB(P)\r\n");
311 if (!Data(ap, SRA_PASS, xpass, strlen(xpass))) {
313 printf("Not enough room\r\n");
320 printf("[ SRA refuses authentication ]\r\n");
321 printf("Trying plaintext login:\r\n");
322 auth_finished(0,AUTH_REJECT);
326 printf("[ SRA accepts you ]\r\n");
330 encrypt_session_key(&skey, 0);
332 auth_finished(ap, AUTH_VALID);
336 printf("Unknown SRA option %d\r\n", data[-1]);
342 sra_status(Authenticator *ap __unused, char *name, int level)
344 if (level < AUTH_USER)
346 if (UserNameRequested && sra_valid) {
347 strcpy(name, UserNameRequested);
353 #define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
354 #define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
357 sra_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
362 buf[buflen-1] = '\0'; /* make sure its NULL terminated */
368 strncpy((char *)buf, " CONTINUE ", buflen);
371 case SRA_REJECT: /* Rejected (reason might follow) */
372 strncpy((char *)buf, " REJECT ", buflen);
375 case SRA_ACCEPT: /* Accepted (name might follow) */
376 strncpy((char *)buf, " ACCEPT ", buflen);
382 ADDC(buf, buflen, '"');
383 for (i = 4; i < cnt; i++)
384 ADDC(buf, buflen, data[i]);
385 ADDC(buf, buflen, '"');
386 ADDC(buf, buflen, '\0');
389 case SRA_KEY: /* Authentication data follows */
390 strncpy((char *)buf, " KEY ", buflen);
394 strncpy((char *)buf, " USER ", buflen);
398 strncpy((char *)buf, " PASS ", buflen);
402 sprintf(lbuf, " %d (unknown)", data[3]);
403 strncpy((char *)buf, lbuf, buflen);
406 for (i = 4; i < cnt; i++) {
407 sprintf(lbuf, " %d", data[i]);
408 strncpy((char *)buf, lbuf, buflen);
416 isroot(const char *usr)
420 if ((pwd=getpwnam(usr))==NULL)
422 return (!pwd->pw_uid);
430 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
435 check_user(char *name, char *cred)
437 char *xpasswd, *salt;
439 if (isroot(name) && !rootterm(line))
441 crypt("AA","*"); /* Waste some time to simulate success */
445 if (pw = sgetpwnam(name)) {
446 if (pw->pw_shell == NULL) {
451 salt = pw->pw_passwd;
452 xpasswd = crypt(cred, salt);
453 /* The strcmp does not catch null passwords! */
454 if (pw == NULL || *pw->pw_passwd == '\0' ||
455 strcmp(xpasswd, pw->pw_passwd)) {
466 * The following is stolen from ftpd, which stole it from the imap-uw
467 * PAM module and login.c. It is needed because we can't really
468 * "converse" with the user, having already gone to the trouble of
469 * getting their username and password through an encrypted channel.
472 #define COPY_STRING(s) (s ? strdup(s):NULL)
478 typedef struct cred_t cred_t;
481 auth_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata)
484 cred_t *cred = (cred_t *) appdata;
485 struct pam_response *reply =
486 malloc(sizeof(struct pam_response) * num_msg);
491 for (i = 0; i < num_msg; i++) {
492 switch (msg[i]->msg_style) {
493 case PAM_PROMPT_ECHO_ON: /* assume want user name */
494 reply[i].resp_retcode = PAM_SUCCESS;
495 reply[i].resp = COPY_STRING(cred->uname);
496 /* PAM frees resp. */
498 case PAM_PROMPT_ECHO_OFF: /* assume want password */
499 reply[i].resp_retcode = PAM_SUCCESS;
500 reply[i].resp = COPY_STRING(cred->pass);
501 /* PAM frees resp. */
505 reply[i].resp_retcode = PAM_SUCCESS;
506 reply[i].resp = NULL;
508 default: /* unknown message style */
519 * The PAM version as a side effect may put a new username in *name.
522 check_user(char *name, char *cred)
524 pam_handle_t *pamh = NULL;
528 cred_t auth_cred = { name, cred };
529 struct pam_conv conv = { &auth_conv, &auth_cred };
531 e = pam_start("telnetd", name, &conv, &pamh);
532 if (e != PAM_SUCCESS) {
533 syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
537 #if 0 /* Where can we find this value? */
538 e = pam_set_item(pamh, PAM_RHOST, remotehost);
539 if (e != PAM_SUCCESS) {
540 syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
541 pam_strerror(pamh, e));
546 e = pam_authenticate(pamh, 0);
550 * With PAM we support the concept of a "template"
551 * user. The user enters a login name which is
552 * authenticated by PAM, usually via a remote service
553 * such as RADIUS or TACACS+. If authentication
554 * succeeds, a different but related "template" name
555 * is used for setting the credentials, shell, and
556 * home directory. The name the user enters need only
557 * exist on the remote authentication server, but the
558 * template name must be present in the local password
561 * This is supported by two various mechanisms in the
562 * individual modules. However, from the application's
563 * point of view, the template user is always passed
564 * back as a changed value of the PAM_USER item.
566 if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
570 syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
571 pam_strerror(pamh, e));
572 if (isroot(name) && !rootterm(line))
579 case PAM_USER_UNKNOWN:
585 syslog(LOG_ERR, "auth_pam: %s", pam_strerror(pamh, e));
590 if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
591 syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
599 #endif /* ENCRYPTION */