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
30 * $FreeBSD: src/crypto/telnet/libtelnet/sra.c,v 1.1.2.7 2002/05/16 08:46:49 markm Exp $
31 * $DragonFly: src/crypto/telnet/libtelnet/sra.c,v 1.3 2006/01/17 23:50:34 dillon Exp $
36 #include <sys/types.h>
37 #include <arpa/telnet.h>
46 #include <security/pam_appl.h>
56 char pka
[HEXKEYBYTES
+1], ska
[HEXKEYBYTES
+1], pkb
[HEXKEYBYTES
+1];
57 char *user
, *pass
, *xuser
, *xpass
;
63 extern int auth_debug_mode
;
66 static int sra_valid
= 0;
67 static int passwd_sent
= 0;
69 static unsigned char str_data
[1024] = { IAC
, SB
, TELOPT_AUTHENTICATION
, 0,
74 #define SRA_CONTINUE 2
79 static int check_user(char *, char *);
81 /* support routine to send out authentication message */
83 Data(Authenticator
*ap
, int type
, void *d
, int c
)
85 unsigned char *p
= str_data
+ 4;
86 unsigned char *cd
= (unsigned char *)d
;
89 c
= strlen((char *)cd
);
91 if (auth_debug_mode
) {
92 printf("%s:%d: [%d] (%d)",
93 str_data
[3] == TELQUAL_IS
? ">>>IS" : ">>>REPLY",
103 if ((*p
++ = *cd
++) == IAC
)
108 if (str_data
[3] == TELQUAL_IS
)
109 printsub('>', &str_data
[2], p
- (&str_data
[2]));
110 return(net_write(str_data
, p
- str_data
));
114 sra_init(Authenticator
*ap __unused
, int server
)
117 str_data
[3] = TELQUAL_REPLY
;
119 str_data
[3] = TELQUAL_IS
;
121 user
= (char *)malloc(256);
122 xuser
= (char *)malloc(513);
123 pass
= (char *)malloc(PASS_SIZE
);
124 xpass
= (char *)malloc(513);
126 if (user
== NULL
|| xuser
== NULL
|| pass
== NULL
|| xpass
==
128 return 0; /* malloc failed */
136 /* client received a go-ahead for sra */
138 sra_send(Authenticator
*ap
)
143 printf("Sent PKA to server.\r\n" );
144 printf("Trying SRA secure login:\r\n");
145 if (!Data(ap
, SRA_KEY
, (void *)pka
, HEXKEYBYTES
)) {
147 printf("Not enough room for authentication data\r\n");
154 /* server received an IS -- could be SRA KEY, USER, or PASS */
156 sra_is(Authenticator
*ap
, unsigned char *data
, int cnt
)
166 if (cnt
< HEXKEYBYTES
) {
167 Data(ap
, SRA_REJECT
, (void *)0, 0);
168 auth_finished(ap
, AUTH_USER
);
169 if (auth_debug_mode
) {
170 printf("SRA user rejected for bad PKB\r\n");
175 printf("Sent pka\r\n");
176 if (!Data(ap
, SRA_KEY
, (void *)pka
, HEXKEYBYTES
)) {
178 printf("Not enough room\r\n");
181 memcpy(pkb
,data
,HEXKEYBYTES
);
182 pkb
[HEXKEYBYTES
] = '\0';
183 common_key(ska
,pkb
,&ik
,&ck
);
188 if (cnt
> 512) /* Attempted buffer overflow */
190 memcpy(xuser
,data
,cnt
);
192 pk_decode(xuser
,user
,&ck
);
193 auth_encrypt_user(user
);
194 Data(ap
, SRA_CONTINUE
, (void *)0, 0);
199 if (cnt
> 512) /* Attempted buffer overflow */
202 memcpy(xpass
,data
,cnt
);
204 pk_decode(xpass
,pass
,&ck
);
206 /* check user's password */
207 valid
= check_user(user
,pass
);
210 Data(ap
, SRA_ACCEPT
, (void *)0, 0);
214 encrypt_session_key(&skey
, 1);
217 auth_finished(ap
, AUTH_VALID
);
218 if (auth_debug_mode
) {
219 printf("SRA user accepted\r\n");
223 Data(ap
, SRA_CONTINUE
, (void *)0, 0);
225 Data(ap, SRA_REJECT, (void *)0, 0);
227 auth_finished(ap, AUTH_REJECT);
229 if (auth_debug_mode
) {
230 printf("SRA user failed\r\n");
237 printf("Unknown SRA option %d\r\n", data
[-1]);
240 Data(ap
, SRA_REJECT
, 0, 0);
242 auth_finished(ap
, AUTH_REJECT
);
245 /* client received REPLY -- could be SRA KEY, CONTINUE, ACCEPT, or REJECT */
247 sra_reply(Authenticator
*ap
, unsigned char *data
, int cnt
)
249 char uprompt
[256],tuser
[256];
258 /* calculate common key */
259 if (cnt
< HEXKEYBYTES
) {
260 if (auth_debug_mode
) {
261 printf("SRA user rejected for bad PKB\r\n");
265 memcpy(pkb
,data
,HEXKEYBYTES
);
266 pkb
[HEXKEYBYTES
] = '\0';
268 common_key(ska
,pkb
,&ik
,&ck
);
273 memset(tuser
,0,sizeof(tuser
));
274 sprintf(uprompt
,"User (%s): ",UserNameRequested
);
275 telnet_gets(uprompt
,tuser
,255,1);
276 if (tuser
[0] == '\n' || tuser
[0] == '\r' )
277 strcpy(user
,UserNameRequested
);
279 /* telnet_gets leaves the newline on */
280 for(i
=0;i
<sizeof(tuser
);i
++) {
281 if (tuser
[i
] == '\n') {
288 pk_encode(user
,xuser
,&ck
);
292 printf("Sent KAB(U)\r\n");
293 if (!Data(ap
, SRA_USER
, (void *)xuser
, strlen(xuser
))) {
295 printf("Not enough room\r\n");
303 printf("[ SRA login failed ]\r\n");
306 /* encode password */
307 memset(pass
,0,PASS_SIZE
);
308 telnet_gets("Password: ",pass
,PASS_SIZE
-1,0);
309 pk_encode(pass
,xpass
,&ck
);
312 printf("Sent KAB(P)\r\n");
313 if (!Data(ap
, SRA_PASS
, (void *)xpass
, strlen(xpass
))) {
315 printf("Not enough room\r\n");
322 printf("[ SRA refuses authentication ]\r\n");
323 printf("Trying plaintext login:\r\n");
324 auth_finished(0,AUTH_REJECT
);
328 printf("[ SRA accepts you ]\r\n");
332 encrypt_session_key(&skey
, 0);
334 auth_finished(ap
, AUTH_VALID
);
338 printf("Unknown SRA option %d\r\n", data
[-1]);
344 sra_status(Authenticator
*ap __unused
, char *name
, int level
)
346 if (level
< AUTH_USER
)
348 if (UserNameRequested
&& sra_valid
) {
349 strcpy(name
, UserNameRequested
);
355 #define BUMP(buf, len) while (*(buf)) {++(buf), --(len);}
356 #define ADDC(buf, len, c) if ((len) > 0) {*(buf)++ = (c); --(len);}
359 sra_printsub(unsigned char *data
, int cnt
, unsigned char *buf
, int buflen
)
364 buf
[buflen
-1] = '\0'; /* make sure its NULL terminated */
370 strncpy((char *)buf
, " CONTINUE ", buflen
);
373 case SRA_REJECT
: /* Rejected (reason might follow) */
374 strncpy((char *)buf
, " REJECT ", buflen
);
377 case SRA_ACCEPT
: /* Accepted (name might follow) */
378 strncpy((char *)buf
, " ACCEPT ", buflen
);
384 ADDC(buf
, buflen
, '"');
385 for (i
= 4; i
< cnt
; i
++)
386 ADDC(buf
, buflen
, data
[i
]);
387 ADDC(buf
, buflen
, '"');
388 ADDC(buf
, buflen
, '\0');
391 case SRA_KEY
: /* Authentication data follows */
392 strncpy((char *)buf
, " KEY ", buflen
);
396 strncpy((char *)buf
, " USER ", buflen
);
400 strncpy((char *)buf
, " PASS ", buflen
);
404 sprintf(lbuf
, " %d (unknown)", data
[3]);
405 strncpy((char *)buf
, lbuf
, buflen
);
408 for (i
= 4; i
< cnt
; i
++) {
409 sprintf(lbuf
, " %d", data
[i
]);
410 strncpy((char *)buf
, lbuf
, buflen
);
418 isroot(const char *usr
)
422 if ((pwd
=getpwnam(usr
))==NULL
)
424 return (!pwd
->pw_uid
);
432 return ((t
= getttynam(ttyn
)) && t
->ty_status
& TTY_SECURE
);
437 check_user(char *name
, char *cred
)
440 char *xpasswd
, *salt
;
442 if (isroot(name
) && !rootterm(line
))
444 crypt("AA","*"); /* Waste some time to simulate success */
448 if (pw
= sgetpwnam(name
)) {
449 if (pw
->pw_shell
== NULL
) {
450 pw
= (struct passwd
*) NULL
;
454 salt
= pw
->pw_passwd
;
455 xpasswd
= crypt(cred
, salt
);
456 /* The strcmp does not catch null passwords! */
457 if (pw
== NULL
|| *pw
->pw_passwd
== '\0' ||
458 strcmp(xpasswd
, pw
->pw_passwd
)) {
459 pw
= (struct passwd
*) NULL
;
469 * The following is stolen from ftpd, which stole it from the imap-uw
470 * PAM module and login.c. It is needed because we can't really
471 * "converse" with the user, having already gone to the trouble of
472 * getting their username and password through an encrypted channel.
475 #define COPY_STRING(s) (s ? strdup(s):NULL)
481 typedef struct cred_t cred_t
;
484 auth_conv(int num_msg
, const struct pam_message
**msg
, struct pam_response
**resp
, void *appdata
)
487 cred_t
*cred
= (cred_t
*) appdata
;
488 struct pam_response
*reply
=
489 malloc(sizeof(struct pam_response
) * num_msg
);
494 for (i
= 0; i
< num_msg
; i
++) {
495 switch (msg
[i
]->msg_style
) {
496 case PAM_PROMPT_ECHO_ON
: /* assume want user name */
497 reply
[i
].resp_retcode
= PAM_SUCCESS
;
498 reply
[i
].resp
= COPY_STRING(cred
->uname
);
499 /* PAM frees resp. */
501 case PAM_PROMPT_ECHO_OFF
: /* assume want password */
502 reply
[i
].resp_retcode
= PAM_SUCCESS
;
503 reply
[i
].resp
= COPY_STRING(cred
->pass
);
504 /* PAM frees resp. */
508 reply
[i
].resp_retcode
= PAM_SUCCESS
;
509 reply
[i
].resp
= NULL
;
511 default: /* unknown message style */
522 * The PAM version as a side effect may put a new username in *name.
525 check_user(char *name
, char *cred
)
527 pam_handle_t
*pamh
= NULL
;
531 cred_t auth_cred
= { name
, cred
};
532 struct pam_conv conv
= { &auth_conv
, &auth_cred
};
534 e
= pam_start("telnetd", name
, &conv
, &pamh
);
535 if (e
!= PAM_SUCCESS
) {
536 syslog(LOG_ERR
, "pam_start: %s", pam_strerror(pamh
, e
));
540 #if 0 /* Where can we find this value? */
541 e
= pam_set_item(pamh
, PAM_RHOST
, remotehost
);
542 if (e
!= PAM_SUCCESS
) {
543 syslog(LOG_ERR
, "pam_set_item(PAM_RHOST): %s",
544 pam_strerror(pamh
, e
));
549 e
= pam_authenticate(pamh
, 0);
553 * With PAM we support the concept of a "template"
554 * user. The user enters a login name which is
555 * authenticated by PAM, usually via a remote service
556 * such as RADIUS or TACACS+. If authentication
557 * succeeds, a different but related "template" name
558 * is used for setting the credentials, shell, and
559 * home directory. The name the user enters need only
560 * exist on the remote authentication server, but the
561 * template name must be present in the local password
564 * This is supported by two various mechanisms in the
565 * individual modules. However, from the application's
566 * point of view, the template user is always passed
567 * back as a changed value of the PAM_USER item.
569 if ((e
= pam_get_item(pamh
, PAM_USER
, &item
)) ==
573 syslog(LOG_ERR
, "Couldn't get PAM_USER: %s",
574 pam_strerror(pamh
, e
));
575 if (isroot(name
) && !rootterm(line
))
582 case PAM_USER_UNKNOWN
:
588 syslog(LOG_ERR
, "auth_pam: %s", pam_strerror(pamh
, e
));
593 if ((e
= pam_end(pamh
, e
)) != PAM_SUCCESS
) {
594 syslog(LOG_ERR
, "pam_end: %s", pam_strerror(pamh
, e
));
602 #endif /* ENCRYPTION */