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
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
33 __FBSDID("$FreeBSD$");
37 #include <sys/types.h>
38 #include <arpa/telnet.h>
47 #include <security/pam_appl.h>
57 char pka[HEXKEYBYTES+1], ska[HEXKEYBYTES+1], pkb[HEXKEYBYTES+1];
58 char *user, *pass, *xuser, *xpass;
62 extern int auth_debug_mode;
65 static int sra_valid = 0;
66 static int passwd_sent = 0;
68 static unsigned char str_data[1024] = { IAC, SB, TELOPT_AUTHENTICATION, 0,
73 #define SRA_CONTINUE 2
78 static int check_user(char *, char *);
80 /* support routine to send out authentication message */
82 Data(Authenticator *ap, int type, void *d, int c)
84 unsigned char *p = str_data + 4;
85 unsigned char *cd = (unsigned char *)d;
88 c = strlen((char *)cd);
90 if (auth_debug_mode) {
91 printf("%s:%d: [%d] (%d)",
92 str_data[3] == TELQUAL_IS ? ">>>IS" : ">>>REPLY",
102 if ((*p++ = *cd++) == IAC)
107 if (str_data[3] == TELQUAL_IS)
108 printsub('>', &str_data[2], p - (&str_data[2]));
109 return(net_write(str_data, p - str_data));
113 sra_init(Authenticator *ap __unused, int server)
116 str_data[3] = TELQUAL_REPLY;
118 str_data[3] = TELQUAL_IS;
120 user = (char *)malloc(256);
121 xuser = (char *)malloc(513);
122 pass = (char *)malloc(256);
123 xpass = (char *)malloc(513);
125 if (user == NULL || xuser == NULL || pass == NULL || xpass ==
127 return 0; /* malloc failed */
135 /* client received a go-ahead for sra */
137 sra_send(Authenticator *ap)
142 printf("Sent PKA to server.\r\n" );
143 printf("Trying SRA secure login:\r\n");
144 if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
146 printf("Not enough room for authentication data\r\n");
153 /* server received an IS -- could be SRA KEY, USER, or PASS */
155 sra_is(Authenticator *ap, unsigned char *data, int cnt)
165 if (cnt < HEXKEYBYTES) {
166 Data(ap, SRA_REJECT, (void *)0, 0);
167 auth_finished(ap, AUTH_USER);
168 if (auth_debug_mode) {
169 printf("SRA user rejected for bad PKB\r\n");
174 printf("Sent pka\r\n");
175 if (!Data(ap, SRA_KEY, (void *)pka, HEXKEYBYTES)) {
177 printf("Not enough room\r\n");
180 memcpy(pkb,data,HEXKEYBYTES);
181 pkb[HEXKEYBYTES] = '\0';
182 common_key(ska,pkb,&ik,&ck);
187 if (cnt > 512) /* Attempted buffer overflow */
189 memcpy(xuser,data,cnt);
191 pk_decode(xuser,user,&ck);
192 auth_encrypt_user(user);
193 Data(ap, SRA_CONTINUE, (void *)0, 0);
198 if (cnt > 512) /* Attempted buffer overflow */
201 memcpy(xpass,data,cnt);
203 pk_decode(xpass,pass,&ck);
205 /* check user's password */
206 valid = check_user(user,pass);
209 Data(ap, SRA_ACCEPT, (void *)0, 0);
213 encrypt_session_key(&skey, 1);
216 auth_finished(ap, AUTH_VALID);
217 if (auth_debug_mode) {
218 printf("SRA user accepted\r\n");
222 Data(ap, SRA_CONTINUE, (void *)0, 0);
224 Data(ap, SRA_REJECT, (void *)0, 0);
226 auth_finished(ap, AUTH_REJECT);
228 if (auth_debug_mode) {
229 printf("SRA user failed\r\n");
236 printf("Unknown SRA option %d\r\n", data[-1]);
239 Data(ap, SRA_REJECT, 0, 0);
241 auth_finished(ap, AUTH_REJECT);
244 /* client received REPLY -- could be SRA KEY, CONTINUE, ACCEPT, or REJECT */
246 sra_reply(Authenticator *ap, unsigned char *data, int cnt)
248 char uprompt[256],tuser[256];
257 /* calculate common key */
258 if (cnt < HEXKEYBYTES) {
259 if (auth_debug_mode) {
260 printf("SRA user rejected for bad PKB\r\n");
264 memcpy(pkb,data,HEXKEYBYTES);
265 pkb[HEXKEYBYTES] = '\0';
267 common_key(ska,pkb,&ik,&ck);
272 memset(tuser,0,sizeof(tuser));
273 sprintf(uprompt,"User (%s): ",UserNameRequested);
274 telnet_gets(uprompt,tuser,255,1);
275 if (tuser[0] == '\n' || tuser[0] == '\r' )
276 strcpy(user,UserNameRequested);
278 /* telnet_gets leaves the newline on */
279 for(i=0;i<sizeof(tuser);i++) {
280 if (tuser[i] == '\n') {
287 pk_encode(user,xuser,&ck);
291 printf("Sent KAB(U)\r\n");
292 if (!Data(ap, SRA_USER, (void *)xuser, strlen(xuser))) {
294 printf("Not enough room\r\n");
302 printf("[ SRA login failed ]\r\n");
305 /* encode password */
307 telnet_gets("Password: ",pass,255,0);
308 pk_encode(pass,xpass,&ck);
311 printf("Sent KAB(P)\r\n");
312 if (!Data(ap, SRA_PASS, (void *)xpass, strlen(xpass))) {
314 printf("Not enough room\r\n");
321 printf("[ SRA refuses authentication ]\r\n");
322 printf("Trying plaintext login:\r\n");
323 auth_finished(0,AUTH_REJECT);
327 printf("[ SRA accepts you ]\r\n");
331 encrypt_session_key(&skey, 0);
333 auth_finished(ap, AUTH_VALID);
337 printf("Unknown SRA option %d\r\n", data[-1]);
343 sra_status(Authenticator *ap __unused, char *name, int level)
345 if (level < AUTH_USER)
347 if (UserNameRequested && sra_valid) {
348 strcpy(name, UserNameRequested);
354 #define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
355 #define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
358 sra_printsub(unsigned char *data, int cnt, unsigned char *buf, int buflen)
363 buf[buflen-1] = '\0'; /* make sure its NULL terminated */
369 strncpy((char *)buf, " CONTINUE ", buflen);
372 case SRA_REJECT: /* Rejected (reason might follow) */
373 strncpy((char *)buf, " REJECT ", buflen);
376 case SRA_ACCEPT: /* Accepted (name might follow) */
377 strncpy((char *)buf, " ACCEPT ", buflen);
383 ADDC(buf, buflen, '"');
384 for (i = 4; i < cnt; i++)
385 ADDC(buf, buflen, data[i]);
386 ADDC(buf, buflen, '"');
387 ADDC(buf, buflen, '\0');
390 case SRA_KEY: /* Authentication data follows */
391 strncpy((char *)buf, " KEY ", buflen);
395 strncpy((char *)buf, " USER ", buflen);
399 strncpy((char *)buf, " PASS ", buflen);
403 sprintf(lbuf, " %d (unknown)", data[3]);
404 strncpy((char *)buf, lbuf, buflen);
407 for (i = 4; i < cnt; i++) {
408 sprintf(lbuf, " %d", data[i]);
409 strncpy((char *)buf, lbuf, buflen);
417 isroot(const char *usr)
421 if ((pwd=getpwnam(usr))==NULL)
423 return (!pwd->pw_uid);
431 return ((t = getttynam(ttyn)) && t->ty_status & TTY_SECURE);
436 check_user(char *name, char *cred)
439 char *xpasswd, *salt;
441 if (isroot(name) && !rootterm(line))
443 crypt("AA","*"); /* Waste some time to simulate success */
447 if (pw = sgetpwnam(name)) {
448 if (pw->pw_shell == NULL) {
449 pw = (struct passwd *) NULL;
453 salt = pw->pw_passwd;
454 xpasswd = crypt(cred, salt);
455 /* The strcmp does not catch null passwords! */
456 if (pw == NULL || *pw->pw_passwd == '\0' ||
457 strcmp(xpasswd, pw->pw_passwd)) {
458 pw = (struct passwd *) NULL;
468 * The following is stolen from ftpd, which stole it from the imap-uw
469 * PAM module and login.c. It is needed because we can't really
470 * "converse" with the user, having already gone to the trouble of
471 * getting their username and password through an encrypted channel.
474 #define COPY_STRING(s) (s ? strdup(s):NULL)
480 typedef struct cred_t cred_t;
483 auth_conv(int num_msg, const struct pam_message **msg, struct pam_response **resp, void *appdata)
486 cred_t *cred = (cred_t *) appdata;
487 struct pam_response *reply =
488 malloc(sizeof(struct pam_response) * num_msg);
493 for (i = 0; i < num_msg; i++) {
494 switch (msg[i]->msg_style) {
495 case PAM_PROMPT_ECHO_ON: /* assume want user name */
496 reply[i].resp_retcode = PAM_SUCCESS;
497 reply[i].resp = COPY_STRING(cred->uname);
498 /* PAM frees resp. */
500 case PAM_PROMPT_ECHO_OFF: /* assume want password */
501 reply[i].resp_retcode = PAM_SUCCESS;
502 reply[i].resp = COPY_STRING(cred->pass);
503 /* PAM frees resp. */
507 reply[i].resp_retcode = PAM_SUCCESS;
508 reply[i].resp = NULL;
510 default: /* unknown message style */
521 * The PAM version as a side effect may put a new username in *name.
524 check_user(char *name, char *cred)
526 pam_handle_t *pamh = NULL;
530 cred_t auth_cred = { name, cred };
531 struct pam_conv conv = { &auth_conv, &auth_cred };
533 e = pam_start("telnetd", name, &conv, &pamh);
534 if (e != PAM_SUCCESS) {
535 syslog(LOG_ERR, "pam_start: %s", pam_strerror(pamh, e));
539 #if 0 /* Where can we find this value? */
540 e = pam_set_item(pamh, PAM_RHOST, remotehost);
541 if (e != PAM_SUCCESS) {
542 syslog(LOG_ERR, "pam_set_item(PAM_RHOST): %s",
543 pam_strerror(pamh, e));
548 e = pam_authenticate(pamh, 0);
552 * With PAM we support the concept of a "template"
553 * user. The user enters a login name which is
554 * authenticated by PAM, usually via a remote service
555 * such as RADIUS or TACACS+. If authentication
556 * succeeds, a different but related "template" name
557 * is used for setting the credentials, shell, and
558 * home directory. The name the user enters need only
559 * exist on the remote authentication server, but the
560 * template name must be present in the local password
563 * This is supported by two various mechanisms in the
564 * individual modules. However, from the application's
565 * point of view, the template user is always passed
566 * back as a changed value of the PAM_USER item.
568 if ((e = pam_get_item(pamh, PAM_USER, &item)) ==
572 syslog(LOG_ERR, "Couldn't get PAM_USER: %s",
573 pam_strerror(pamh, e));
574 if (isroot(name) && !rootterm(line))
581 case PAM_USER_UNKNOWN:
587 syslog(LOG_ERR, "auth_pam: %s", pam_strerror(pamh, e));
592 if ((e = pam_end(pamh, e)) != PAM_SUCCESS) {
593 syslog(LOG_ERR, "pam_end: %s", pam_strerror(pamh, e));
601 #endif /* ENCRYPTION */