source: trunk/server/source3/pam_smbpass/support.c

Last change on this file was 745, checked in by Silvan Scherrer, 13 years ago

Samba Server: updated trunk to 3.6.0
File size: 19.8 KB
Line 
1/* Unix NT password database implementation, version 0.6.
2 *
3 * This program is free software; you can redistribute it and/or modify it under
4 * the terms of the GNU General Public License as published by the Free
5 * Software Foundation; either version 3 of the License, or (at your option)
6 * any later version.
7 *
8 * This program is distributed in the hope that it will be useful, but WITHOUT
9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
11 * more details.
12 *
13 * You should have received a copy of the GNU General Public License along with
14 * this program; if not, see <http://www.gnu.org/licenses/>.
15 */
16
17#include "config.h"
18#include "includes.h"
19#include "general.h"
20
21#include "support.h"
22#include "secrets.h"
23
24#include "../libcli/auth/libcli_auth.h"
25#if defined(HAVE_SECURITY_PAM_EXT_H)
26#include <security/pam_ext.h>
27#elif defined(HAVE_PAM_PAM_EXT_H)
28#include <pam/pam_ext.h>
29#endif
30
31#if defined(HAVE_SECURITY__PAM_MACROS_H)
32#include <security/_pam_macros.h>
33#elif defined(HAVE_PAM__PAM_MACROS_H)
34#include <pam/_pam_macros.h>
35#endif
36
37#ifdef HAVE_SYSLOG_H
38#include <syslog.h>
39#endif
40
41#define _pam_overwrite(x) \
42do { \
43 register char *__xx__; \
44 if ((__xx__=(x))) \
45 while (*__xx__) \
46 *__xx__++ = '\0'; \
47} while (0)
48
49/*
50 * Don't just free it, forget it too.
51 */
52
53#define _pam_drop(X) \
54do { \
55 if (X) { \
56 free(X); \
57 X=NULL; \
58 } \
59} while (0)
60
61#define _pam_drop_reply(/* struct pam_response * */ reply, /* int */ replies) \
62do { \
63 int reply_i; \
64 \
65 for (reply_i=0; reply_i<replies; ++reply_i) { \
66 if (reply[reply_i].resp) { \
67 _pam_overwrite(reply[reply_i].resp); \
68 free(reply[reply_i].resp); \
69 } \
70 } \
71 if (reply) \
72 free(reply); \
73} while (0)
74
75
76int converse(pam_handle_t *, int, int, struct pam_message **,
77 struct pam_response **);
78int make_remark(pam_handle_t *, unsigned int, int, const char *);
79void _cleanup(pam_handle_t *, void *, int);
80char *_pam_delete(register char *);
81
82/* syslogging function for errors and other information */
83#ifdef HAVE_PAM_VSYSLOG
84void _log_err( pam_handle_t *pamh, int err, const char *format, ... )
85{
86 va_list args;
87
88 va_start(args, format);
89 pam_vsyslog(pamh, err, format, args);
90 va_end(args);
91}
92#else
93void _log_err( pam_handle_t *pamh, int err, const char *format, ... )
94{
95 va_list args;
96 char *mod_format;
97
98 if (asprintf(&mod_format, "(pam_smbpass) %s", format) == -1) {
99 /*
100 * try really, really hard to log something, since
101 * this may have been a message about a malloc()
102 * failure...
103 */
104 va_start(args, format);
105 vsyslog(err | LOG_AUTH, format, args);
106 va_end(args);
107 return;
108 }
109
110 va_start(args, format);
111 vsyslog(err | LOG_AUTH, mod_format, args);
112 va_end(args);
113
114 free(mod_format);
115}
116#endif
117
118/* this is a front-end for module-application conversations */
119
120int converse( pam_handle_t * pamh, int ctrl, int nargs
121 , struct pam_message **message
122 , struct pam_response **response )
123{
124 int retval;
125 struct pam_conv *conv;
126
127 retval = _pam_get_item(pamh, PAM_CONV, &conv);
128 if (retval == PAM_SUCCESS) {
129
130 retval = conv->conv(nargs, (const struct pam_message **) message
131 ,response, conv->appdata_ptr);
132
133 if (retval != PAM_SUCCESS && on(SMB_DEBUG, ctrl)) {
134 _log_err(pamh, LOG_DEBUG, "conversation failure [%s]"
135 ,pam_strerror(pamh, retval));
136 }
137 } else {
138 _log_err(pamh, LOG_ERR, "couldn't obtain coversation function [%s]"
139 ,pam_strerror(pamh, retval));
140 }
141
142 return retval; /* propagate error status */
143}
144
145int make_remark( pam_handle_t * pamh, unsigned int ctrl
146 , int type, const char *text )
147{
148 if (off(SMB__QUIET, ctrl)) {
149 struct pam_message *pmsg[1], msg[1];
150 struct pam_response *resp;
151
152 pmsg[0] = &msg[0];
153 msg[0].msg = CONST_DISCARD(char *, text);
154 msg[0].msg_style = type;
155 resp = NULL;
156
157 return converse(pamh, ctrl, 1, pmsg, &resp);
158 }
159 return PAM_SUCCESS;
160}
161
162
163/* set the control flags for the SMB module. */
164
165int set_ctrl( pam_handle_t *pamh, int flags, int argc, const char **argv )
166{
167 int i = 0;
168 const char *service_file = NULL;
169 unsigned int ctrl;
170
171 ctrl = SMB_DEFAULTS; /* the default selection of options */
172
173 /* set some flags manually */
174
175 /* A good, sane default (matches Samba's behavior). */
176 set( SMB__NONULL, ctrl );
177
178 /* initialize service file location */
179 service_file=get_dyn_CONFIGFILE();
180
181 if (flags & PAM_SILENT) {
182 set( SMB__QUIET, ctrl );
183 }
184
185 /* Run through the arguments once, looking for an alternate smb config
186 file location */
187 while (i < argc) {
188 int j;
189
190 for (j = 0; j < SMB_CTRLS_; ++j) {
191 if (smb_args[j].token
192 && !strncmp(argv[i], smb_args[j].token, strlen(smb_args[j].token)))
193 {
194 break;
195 }
196 }
197
198 if (j == SMB_CONF_FILE) {
199 service_file = argv[i] + 8;
200 }
201 i++;
202 }
203
204 /* Read some options from the Samba config. Can be overridden by
205 the PAM config. */
206 if(lp_load(service_file,True,False,False,True) == False) {
207 _log_err(pamh, LOG_ERR, "Error loading service file %s", service_file);
208 }
209
210 secrets_init();
211
212 if (lp_null_passwords()) {
213 set( SMB__NULLOK, ctrl );
214 }
215
216 /* now parse the rest of the arguments to this module */
217
218 while (argc-- > 0) {
219 int j;
220
221 for (j = 0; j < SMB_CTRLS_; ++j) {
222 if (smb_args[j].token
223 && !strncmp(*argv, smb_args[j].token, strlen(smb_args[j].token)))
224 {
225 break;
226 }
227 }
228
229 if (j >= SMB_CTRLS_) {
230 _log_err(pamh, LOG_ERR, "unrecognized option [%s]", *argv);
231 } else {
232 ctrl &= smb_args[j].mask; /* for turning things off */
233 ctrl |= smb_args[j].flag; /* for turning things on */
234 }
235
236 ++argv; /* step to next argument */
237 }
238
239 /* auditing is a more sensitive version of debug */
240
241 if (on( SMB_AUDIT, ctrl )) {
242 set( SMB_DEBUG, ctrl );
243 }
244 /* return the set of flags */
245
246 return ctrl;
247}
248
249/* use this to free strings. ESPECIALLY password strings */
250
251char * _pam_delete( register char *xx )
252{
253 _pam_overwrite( xx );
254 _pam_drop( xx );
255 return NULL;
256}
257
258void _cleanup( pam_handle_t * pamh, void *x, int error_status )
259{
260 x = _pam_delete( (char *) x );
261}
262
263/* JHT
264 *
265 * Safe duplication of character strings. "Paranoid"; don't leave
266 * evidence of old token around for later stack analysis.
267 *
268 */
269char * smbpXstrDup( pam_handle_t *pamh, const char *x )
270{
271 register char *newstr = NULL;
272
273 if (x != NULL) {
274 register int i;
275
276 for (i = 0; x[i]; ++i); /* length of string */
277 if ((newstr = SMB_MALLOC_ARRAY(char, ++i)) == NULL) {
278 i = 0;
279 _log_err(pamh, LOG_CRIT, "out of memory in smbpXstrDup");
280 } else {
281 while (i-- > 0) {
282 newstr[i] = x[i];
283 }
284 }
285 x = NULL;
286 }
287 return newstr; /* return the duplicate or NULL on error */
288}
289
290/* ************************************************************** *
291 * Useful non-trivial functions *
292 * ************************************************************** */
293
294void _cleanup_failures( pam_handle_t * pamh, void *fl, int err )
295{
296 int quiet;
297 const char *service = NULL;
298 struct _pam_failed_auth *failure;
299
300#ifdef PAM_DATA_SILENT
301 quiet = err & PAM_DATA_SILENT; /* should we log something? */
302#else
303 quiet = 0;
304#endif
305#ifdef PAM_DATA_REPLACE
306 err &= PAM_DATA_REPLACE; /* are we just replacing data? */
307#endif
308 failure = (struct _pam_failed_auth *) fl;
309
310 if (failure != NULL) {
311
312#ifdef PAM_DATA_SILENT
313 if (!quiet && !err) { /* under advisement from Sun,may go away */
314#else
315 if (!quiet) { /* under advisement from Sun,may go away */
316#endif
317
318 /* log the number of authentication failures */
319 if (failure->count != 0) {
320 _pam_get_item( pamh, PAM_SERVICE, &service );
321 _log_err(pamh, LOG_NOTICE
322 , "%d authentication %s "
323 "from %s for service %s as %s(%d)"
324 , failure->count
325 , failure->count == 1 ? "failure" : "failures"
326 , failure->agent
327 , service == NULL ? "**unknown**" : service
328 , failure->user, failure->id );
329 if (failure->count > SMB_MAX_RETRIES) {
330 _log_err(pamh, LOG_ALERT
331 , "service(%s) ignoring max retries; %d > %d"
332 , service == NULL ? "**unknown**" : service
333 , failure->count
334 , SMB_MAX_RETRIES );
335 }
336 }
337 }
338 _pam_delete( failure->agent ); /* tidy up */
339 _pam_delete( failure->user ); /* tidy up */
340 SAFE_FREE( failure );
341 }
342}
343
344int _smb_verify_password( pam_handle_t * pamh, struct samu *sampass,
345 const char *p, unsigned int ctrl )
346{
347 uchar lm_pw[16];
348 uchar nt_pw[16];
349 int retval = PAM_AUTH_ERR;
350 char *data_name;
351 const char *name;
352
353 if (!sampass)
354 return PAM_ABORT;
355
356 name = pdb_get_username(sampass);
357
358#ifdef HAVE_PAM_FAIL_DELAY
359 if (off( SMB_NODELAY, ctrl )) {
360 (void) pam_fail_delay( pamh, 1000000 ); /* 1 sec delay for on failure */
361 }
362#endif
363
364 if (!pdb_get_nt_passwd(sampass))
365 {
366 _log_err(pamh, LOG_DEBUG, "user %s has null SMB password", name);
367
368 if (off( SMB__NONULL, ctrl )
369 && (pdb_get_acct_ctrl(sampass) & ACB_PWNOTREQ))
370 { /* this means we've succeeded */
371 return PAM_SUCCESS;
372 } else {
373 const char *service;
374
375 _pam_get_item( pamh, PAM_SERVICE, &service );
376 _log_err(pamh, LOG_NOTICE, "failed auth request by %s for service %s as %s",
377 uidtoname(getuid()), service ? service : "**unknown**", name);
378 return PAM_AUTH_ERR;
379 }
380 }
381
382 if (asprintf(&data_name, "-SMB-FAIL- %s", name) == -1) {
383 _log_err(pamh, LOG_CRIT, "no memory for data-name" );
384 return PAM_AUTH_ERR;
385 }
386
387 /*
388 * The password we were given wasn't an encrypted password, or it
389 * didn't match the one we have. We encrypt the password now and try
390 * again.
391 */
392
393 nt_lm_owf_gen(p, nt_pw, lm_pw);
394
395 /* the moment of truth -- do we agree with the password? */
396
397 if (!memcmp( nt_pw, pdb_get_nt_passwd(sampass), 16 )) {
398
399 retval = PAM_SUCCESS;
400 if (data_name) { /* reset failures */
401 pam_set_data(pamh, data_name, NULL, _cleanup_failures);
402 }
403 } else {
404
405 const char *service;
406
407 _pam_get_item( pamh, PAM_SERVICE, &service );
408
409 if (data_name != NULL) {
410 struct _pam_failed_auth *newauth = NULL;
411 const struct _pam_failed_auth *old = NULL;
412
413 /* get a failure recorder */
414
415 newauth = SMB_MALLOC_P( struct _pam_failed_auth );
416
417 if (newauth != NULL) {
418
419 /* any previous failures for this user ? */
420 _pam_get_data(pamh, data_name, &old);
421
422 if (old != NULL) {
423 newauth->count = old->count + 1;
424 if (newauth->count >= SMB_MAX_RETRIES) {
425 retval = PAM_MAXTRIES;
426 }
427 } else {
428 _log_err(pamh, LOG_NOTICE,
429 "failed auth request by %s for service %s as %s",
430 uidtoname(getuid()),
431 service ? service : "**unknown**", name);
432 newauth->count = 1;
433 }
434 if (!sid_to_uid(pdb_get_user_sid(sampass), &(newauth->id))) {
435 _log_err(pamh, LOG_NOTICE,
436 "failed auth request by %s for service %s as %s",
437 uidtoname(getuid()),
438 service ? service : "**unknown**", name);
439 }
440 newauth->user = smbpXstrDup( pamh, name );
441 newauth->agent = smbpXstrDup( pamh, uidtoname( getuid() ) );
442 pam_set_data( pamh, data_name, newauth, _cleanup_failures );
443
444 } else {
445 _log_err(pamh, LOG_CRIT, "no memory for failure recorder" );
446 _log_err(pamh, LOG_NOTICE,
447 "failed auth request by %s for service %s as %s(%d)",
448 uidtoname(getuid()),
449 service ? service : "**unknown**", name);
450 }
451 }
452 _log_err(pamh, LOG_NOTICE,
453 "failed auth request by %s for service %s as %s(%d)",
454 uidtoname(getuid()),
455 service ? service : "**unknown**", name);
456 retval = PAM_AUTH_ERR;
457 }
458
459 _pam_delete( data_name );
460
461 return retval;
462}
463
464
465/*
466 * _smb_blankpasswd() is a quick check for a blank password
467 *
468 * returns TRUE if user does not have a password
469 * - to avoid prompting for one in such cases (CG)
470 */
471
472int _smb_blankpasswd( unsigned int ctrl, struct samu *sampass )
473{
474 int retval;
475
476 /*
477 * This function does not have to be too smart if something goes
478 * wrong, return FALSE and let this case to be treated somewhere
479 * else (CG)
480 */
481
482 if (on( SMB__NONULL, ctrl ))
483 return 0; /* will fail but don't let on yet */
484
485 if (!(pdb_get_acct_ctrl(sampass) & ACB_PWNOTREQ))
486 return 0;
487
488 if (pdb_get_nt_passwd(sampass) == NULL)
489 retval = 1;
490 else
491 retval = 0;
492
493 return retval;
494}
495
496/*
497 * obtain a password from the user
498 */
499
500int _smb_read_password( pam_handle_t * pamh, unsigned int ctrl,
501 const char *comment, const char *prompt1,
502 const char *prompt2, const char *data_name, char **pass )
503{
504 int authtok_flag;
505 int retval;
506 char *item = NULL;
507 char *token;
508
509 struct pam_message msg[3], *pmsg[3];
510 struct pam_response *resp;
511 int i, expect;
512
513
514 /* make sure nothing inappropriate gets returned */
515
516 *pass = token = NULL;
517
518 /* which authentication token are we getting? */
519
520 authtok_flag = on(SMB__OLD_PASSWD, ctrl) ? PAM_OLDAUTHTOK : PAM_AUTHTOK;
521
522 /* should we obtain the password from a PAM item ? */
523
524 if (on(SMB_TRY_FIRST_PASS, ctrl) || on(SMB_USE_FIRST_PASS, ctrl)) {
525 retval = _pam_get_item( pamh, authtok_flag, &item );
526 if (retval != PAM_SUCCESS) {
527 /* very strange. */
528 _log_err(pamh, LOG_ALERT,
529 "pam_get_item returned error to smb_read_password");
530 return retval;
531 } else if (item != NULL) { /* we have a password! */
532 *pass = item;
533 item = NULL;
534 return PAM_SUCCESS;
535 } else if (on( SMB_USE_FIRST_PASS, ctrl )) {
536 return PAM_AUTHTOK_RECOVER_ERR; /* didn't work */
537 } else if (on( SMB_USE_AUTHTOK, ctrl )
538 && off( SMB__OLD_PASSWD, ctrl ))
539 {
540 return PAM_AUTHTOK_RECOVER_ERR;
541 }
542 }
543
544 /*
545 * getting here implies we will have to get the password from the
546 * user directly.
547 */
548
549 /* prepare to converse */
550 if (comment != NULL && off(SMB__QUIET, ctrl)) {
551 pmsg[0] = &msg[0];
552 msg[0].msg_style = PAM_TEXT_INFO;
553 msg[0].msg = CONST_DISCARD(char *, comment);
554 i = 1;
555 } else {
556 i = 0;
557 }
558
559 pmsg[i] = &msg[i];
560 msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
561 msg[i++].msg = CONST_DISCARD(char *, prompt1);
562
563 if (prompt2 != NULL) {
564 pmsg[i] = &msg[i];
565 msg[i].msg_style = PAM_PROMPT_ECHO_OFF;
566 msg[i++].msg = CONST_DISCARD(char *, prompt2);
567 expect = 2;
568 } else
569 expect = 1;
570
571 resp = NULL;
572
573 retval = converse( pamh, ctrl, i, pmsg, &resp );
574
575 if (resp != NULL) {
576 int j = comment ? 1 : 0;
577 /* interpret the response */
578
579 if (retval == PAM_SUCCESS) { /* a good conversation */
580
581 token = smbpXstrDup(pamh, resp[j++].resp);
582 if (token != NULL) {
583 if (expect == 2) {
584 /* verify that password entered correctly */
585 if (!resp[j].resp || strcmp( token, resp[j].resp )) {
586 _pam_delete( token );
587 retval = PAM_AUTHTOK_RECOVER_ERR;
588 make_remark( pamh, ctrl, PAM_ERROR_MSG
589 , MISTYPED_PASS );
590 }
591 }
592 } else {
593 _log_err(pamh, LOG_NOTICE,
594 "could not recover authentication token");
595 }
596 }
597
598 /* tidy up */
599 _pam_drop_reply( resp, expect );
600
601 } else {
602 retval = (retval == PAM_SUCCESS) ? PAM_AUTHTOK_RECOVER_ERR : retval;
603 }
604
605 if (retval != PAM_SUCCESS) {
606 if (on( SMB_DEBUG, ctrl ))
607 _log_err(pamh, LOG_DEBUG, "unable to obtain a password");
608 return retval;
609 }
610 /* 'token' is the entered password */
611
612 if (off( SMB_NOT_SET_PASS, ctrl )) {
613
614 /* we store this password as an item */
615
616 retval = pam_set_item( pamh, authtok_flag, (const void *)token );
617 _pam_delete( token ); /* clean it up */
618 if (retval != PAM_SUCCESS
619 || (retval = _pam_get_item( pamh, authtok_flag
620 ,&item )) != PAM_SUCCESS)
621 {
622 _log_err(pamh, LOG_CRIT, "error manipulating password");
623 return retval;
624 }
625 } else {
626 /*
627 * then store it as data specific to this module. pam_end()
628 * will arrange to clean it up.
629 */
630
631 retval = pam_set_data( pamh, data_name, (void *) token, _cleanup );
632 if (retval != PAM_SUCCESS
633 || (retval = _pam_get_data( pamh, data_name, &item ))
634 != PAM_SUCCESS)
635 {
636 _log_err(pamh, LOG_CRIT, "error manipulating password data [%s]",
637 pam_strerror( pamh, retval ));
638 _pam_delete( token );
639 item = NULL;
640 return retval;
641 }
642 token = NULL; /* break link to password */
643 }
644
645 *pass = item;
646 item = NULL; /* break link to password */
647
648 return PAM_SUCCESS;
649}
650
651int _pam_smb_approve_pass(pam_handle_t * pamh,
652 unsigned int ctrl,
653 const char *pass_old,
654 const char *pass_new )
655{
656
657 /* Further checks should be handled through module stacking. -SRL */
658 if (pass_new == NULL || (pass_old && !strcmp( pass_old, pass_new )))
659 {
660 if (on(SMB_DEBUG, ctrl)) {
661 _log_err(pamh, LOG_DEBUG,
662 "passwd: bad authentication token (null or unchanged)");
663 }
664 make_remark( pamh, ctrl, PAM_ERROR_MSG, pass_new == NULL ?
665 "No password supplied" : "Password unchanged" );
666 return PAM_AUTHTOK_ERR;
667 }
668
669 return PAM_SUCCESS;
670}
671
672/*
673 * Work around the pam API that has functions with void ** as parameters
674 * These lead to strict aliasing warnings with gcc.
675 */
676int _pam_get_item(const pam_handle_t *pamh,
677 int item_type,
678 const void *_item)
679{
680 const void **item = (const void **)_item;
681 return pam_get_item(pamh, item_type, item);
682}
683
684int _pam_get_data(const pam_handle_t *pamh,
685 const char *module_data_name,
686 const void *_data)
687{
688 const void **data = (const void **)_data;
689 return pam_get_data(pamh, module_data_name, data);
690}
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