1 /*
2 * "$Id: auth.c 9233 2010-08-10 06:15:55Z mike $"
3 *
4 * Authentication functions for the Common UNIX Printing System (CUPS).
5 *
6 * Copyright 2007-2010 by Apple Inc.
7 * Copyright 1997-2007 by Easy Software Products.
8 *
9 * This file contains Kerberos support code, copyright 2006 by
10 * Jelmer Vernooij.
11 *
12 * These coded instructions, statements, and computer programs are the
13 * property of Apple Inc. and are protected by Federal copyright
14 * law. Distribution and use rights are outlined in the file "LICENSE.txt"
15 * which should have been included with this file. If this file is
16 * file is missing or damaged, see the license at "http://www.cups.org/".
17 *
18 * This file is subject to the Apple OS-Developed Software exception.
19 *
20 * Contents:
21 *
22 * cupsDoAuthentication() - Authenticate a request.
23 * cups_get_gssname() - Get GSSAPI name for authentication.
24 * cups_gss_printf() - Show error messages from GSSAPI...
25 * cups_local_auth() - Get the local authorization certificate if
26 * available/applicable...
27 */
28
29 /*
30 * Include necessary headers...
31 */
32
33 #include "globals.h"
34 #include "debug.h"
35 #include <stdlib.h>
36 #include <ctype.h>
37 #include <errno.h>
38 #include <fcntl.h>
39 #include <sys/stat.h>
40 #if defined(WIN32) || defined(__EMX__)
41 # include <io.h>
42 #else
43 # include <unistd.h>
44 #endif /* WIN32 || __EMX__ */
45
46 #if HAVE_AUTHORIZATION_H
47 # include <Security/Authorization.h>
48 # ifdef HAVE_SECBASEPRIV_H
49 # include <Security/SecBasePriv.h>
50 # else
51 extern const char *cssmErrorString(int error);
52 # endif /* HAVE_SECBASEPRIV_H */
53 #endif /* HAVE_AUTHORIZATION_H */
54
55 #if defined(SO_PEERCRED) && defined(AF_LOCAL)
56 # include <pwd.h>
57 #endif /* SO_PEERCRED && AF_LOCAL */
58
59
60 /*
61 * Local functions...
62 */
63
64 #ifdef HAVE_GSSAPI
65 static gss_name_t cups_get_gssname(http_t *http, const char *service_name);
66 # ifdef DEBUG
67 static void cups_gss_printf(OM_uint32 major_status, OM_uint32 minor_status,
68 const char *message);
69 # else
70 # define cups_gss_printf(major, minor, message)
71 # endif /* DEBUG */
72 #endif /* HAVE_GSSAPI */
73 static int cups_local_auth(http_t *http);
74
75
76 /*
77 * 'cupsDoAuthentication()' - Authenticate a request.
78 *
79 * This function should be called in response to a @code HTTP_UNAUTHORIZED@
80 * status, prior to resubmitting your request.
81 *
82 * @since CUPS 1.1.20/Mac OS X 10.4@
83 */
84
85 int /* O - 0 on success, -1 on error */
cupsDoAuthentication(http_t * http,const char * method,const char * resource)86 cupsDoAuthentication(
87 http_t *http, /* I - Connection to server or @code CUPS_HTTP_DEFAULT@ */
88 const char *method, /* I - Request method ("GET", "POST", "PUT") */
89 const char *resource) /* I - Resource path */
90 {
91 const char *password; /* Password string */
92 char prompt[1024], /* Prompt for user */
93 realm[HTTP_MAX_VALUE], /* realm="xyz" string */
94 nonce[HTTP_MAX_VALUE]; /* nonce="xyz" string */
95 int localauth; /* Local authentication result */
96 _cups_globals_t *cg; /* Global data */
97
98
99 DEBUG_printf(("cupsDoAuthentication(http=%p, method=\"%s\", resource=\"%s\")",
100 http, method, resource));
101
102 if (!http)
103 http = _cupsConnect();
104
105 if (!http || !method || !resource)
106 return (-1);
107
108 DEBUG_printf(("2cupsDoAuthentication: digest_tries=%d, userpass=\"%s\"",
109 http->digest_tries, http->userpass));
110 DEBUG_printf(("2cupsDoAuthentication: WWW-Authenticate=\"%s\"",
111 httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE)));
112
113 /*
114 * Clear the current authentication string...
115 */
116
117 httpSetAuthString(http, NULL, NULL);
118
119 /*
120 * See if we can do local authentication...
121 */
122
123 if (http->digest_tries < 3)
124 {
125 if ((localauth = cups_local_auth(http)) == 0)
126 {
127 DEBUG_printf(("2cupsDoAuthentication: authstring=\"%s\"",
128 http->authstring));
129
130 if (http->status == HTTP_UNAUTHORIZED)
131 http->digest_tries ++;
132
133 return (0);
134 }
135 else if (localauth == -1)
136 {
137 http->status = HTTP_AUTHORIZATION_CANCELED;
138 return (-1); /* Error or canceled */
139 }
140 }
141
142 /*
143 * Nope, see if we should retry the current username:password...
144 */
145
146 if ((http->digest_tries > 1 || !http->userpass[0]) &&
147 strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
148 {
149 /*
150 * Nope - get a new password from the user...
151 */
152
153 cg = _cupsGlobals();
154
155 if (!cg->lang_default)
156 cg->lang_default = cupsLangDefault();
157
158 snprintf(prompt, sizeof(prompt),
159 _cupsLangString(cg->lang_default, _("Password for %s on %s? ")),
160 cupsUser(),
161 http->hostname[0] == '/' ? "localhost" : http->hostname);
162
163 http->digest_tries = strncasecmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE],
164 "Digest", 5) != 0;
165 http->userpass[0] = '\0';
166
167 if ((password = cupsGetPassword2(prompt, http, method, resource)) == NULL)
168 {
169 http->status = HTTP_AUTHORIZATION_CANCELED;
170 return (-1);
171 }
172
173 if (!password[0])
174 {
175 http->status = HTTP_AUTHORIZATION_CANCELED;
176 return (-1);
177 }
178
179 snprintf(http->userpass, sizeof(http->userpass), "%s:%s", cupsUser(),
180 password);
181 }
182 else if (http->status == HTTP_UNAUTHORIZED)
183 http->digest_tries ++;
184
185 if (http->status == HTTP_UNAUTHORIZED && http->digest_tries >= 3)
186 {
187 DEBUG_printf(("1cupsDoAuthentication: Too many authentication tries (%d)",
188 http->digest_tries));
189
190 http->status = HTTP_AUTHORIZATION_CANCELED;
191 return (-1);
192 }
193
194 /*
195 * Got a password; encode it for the server...
196 */
197
198 if (!strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
199 {
200 #ifdef HAVE_GSSAPI
201 /*
202 * Kerberos authentication...
203 */
204
205 OM_uint32 minor_status, /* Minor status code */
206 major_status; /* Major status code */
207 gss_buffer_desc output_token = GSS_C_EMPTY_BUFFER,
208 /* Output token */
209 input_token = GSS_C_EMPTY_BUFFER;
210 /* Input token */
211 char *gss_service_name;
212 /* GSS service name */
213 # ifdef USE_SPNEGO
214 const char *authorization;
215 /* Pointer into Authorization string */
216 # endif /* USE_SPNEGO */
217
218
219 # ifdef __APPLE__
220 /*
221 * If the weak-linked GSSAPI/Kerberos library is not present, don't try
222 * to use it...
223 */
224
225 if (gss_init_sec_context == NULL)
226 {
227 DEBUG_puts("1cupsDoAuthentication: Weak-linked GSSAPI/Kerberos framework "
228 "is not present");
229 http->status = HTTP_AUTHORIZATION_CANCELED;
230
231 return (-1);
232 }
233 # endif /* __APPLE__ */
234
235 if (http->gssname == GSS_C_NO_NAME)
236 {
237 if ((gss_service_name = getenv("CUPS_GSSSERVICENAME")) == NULL)
238 gss_service_name = CUPS_DEFAULT_GSSSERVICENAME;
239 else
240 DEBUG_puts("2cupsDoAuthentication: GSS service name set via "
241 "environment variable");
242
243 http->gssname = cups_get_gssname(http, gss_service_name);
244 }
245
246 # ifdef USE_SPNEGO /* We don't implement SPNEGO just yet... */
247 /*
248 * Find the start of the Kerberos input token...
249 */
250
251 authorization = httpGetField(http, HTTP_FIELD_WWW_AUTHENTICATE);
252
253 authorization += 9;
254 while (*authorization && _cups_isspace(*authorization))
255 authorization ++;
256
257 if (*authorization)
258 {
259 /*
260 * Decode the authorization string to get the input token...
261 */
262
263 int len = strlen(authorization);
264
265 input_token.value = malloc(len);
266 input_token.value = httpDecode64_2(input_token.value, &len,
267 authorization);
268 input_token.length = len;
269
270 # ifdef DEBUG
271 {
272 char *ptr = (char *)input_token.value;
273 int left = len;
274
275 fputs("input_token=", stdout);
276 while (left > 0)
277 {
278 if (*ptr < ' ')
279 printf("\\%03o", *ptr & 255);
280 else
281 putchar(*ptr);
282 ptr ++;
283 left --;
284 }
285 putchar('\n');
286 }
287 # endif /* DEBUG */
288 }
289 # endif /* USE_SPNEGO */
290
291 if (http->gssctx != GSS_C_NO_CONTEXT)
292 {
293 gss_delete_sec_context(&minor_status, &http->gssctx, GSS_C_NO_BUFFER);
294 http->gssctx = GSS_C_NO_CONTEXT;
295 }
296
297 major_status = gss_init_sec_context(&minor_status, GSS_C_NO_CREDENTIAL,
298 &http->gssctx,
299 http->gssname, http->gssmech,
300 #ifdef GSS_C_DELEG_POLICY_FLAG
301 GSS_C_DELEG_POLICY_FLAG |
302 #endif /* GSS_C_DELEG_POLICY_FLAG */
303 GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG,
304 GSS_C_INDEFINITE,
305 GSS_C_NO_CHANNEL_BINDINGS,
306 &input_token, &http->gssmech,
307 &output_token, NULL, NULL);
308
309 if (input_token.value)
310 free(input_token.value);
311
312 if (GSS_ERROR(major_status))
313 {
314 cups_gss_printf(major_status, minor_status,
315 "cupsDoAuthentication: Unable to initialize security "
316 "context");
317 http->status = HTTP_AUTHORIZATION_CANCELED;
318
319 return (-1);
320 }
321
322 if (major_status == GSS_S_CONTINUE_NEEDED)
323 cups_gss_printf(major_status, minor_status,
324 "cupsDoAuthentication: Continuation needed!");
325
326 if (output_token.length > 0 && output_token.length <= 65536)
327 {
328 /*
329 * Allocate the authorization string since Windows KDCs can have
330 * arbitrarily large credentials...
331 */
332
333 int authsize = 10 + /* "Negotiate " */
334 output_token.length * 4 / 3 + 1 + /* Base64 */
335 1; /* nul */
336
337 httpSetAuthString(http, NULL, NULL);
338
339 if ((http->authstring = malloc(authsize)) == NULL)
340 {
341 http->authstring = http->_authstring;
342 authsize = sizeof(http->_authstring);
343 }
344
345 strcpy(http->authstring, "Negotiate ");
346 httpEncode64_2(http->authstring + 10, authsize - 10, output_token.value,
347 output_token.length);
348
349 gss_release_buffer(&minor_status, &output_token);
350 }
351 else
352 {
353 DEBUG_printf(("1cupsDoAuthentication: Kerberos credentials too large - "
354 "%d bytes!", (int)output_token.length));
355 http->status = HTTP_AUTHORIZATION_CANCELED;
356 gss_release_buffer(&minor_status, &output_token);
357
358 return (-1);
359 }
360 #endif /* HAVE_GSSAPI */
361 }
362 else if (strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Digest", 6))
363 {
364 /*
365 * Basic authentication...
366 */
367
368 char encode[256]; /* Base64 buffer */
369
370
371 httpEncode64_2(encode, sizeof(encode), http->userpass,
372 (int)strlen(http->userpass));
373 httpSetAuthString(http, "Basic", encode);
374 }
375 else
376 {
377 /*
378 * Digest authentication...
379 */
380
381 char encode[33], /* MD5 buffer */
382 digest[1024]; /* Digest auth data */
383
384
385 httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "realm", realm);
386 httpGetSubField(http, HTTP_FIELD_WWW_AUTHENTICATE, "nonce", nonce);
387
388 httpMD5(cupsUser(), realm, strchr(http->userpass, ':') + 1, encode);
389 httpMD5Final(nonce, method, resource, encode);
390 snprintf(digest, sizeof(digest),
391 "username=\"%s\", realm=\"%s\", nonce=\"%s\", uri=\"%s\", "
392 "response=\"%s\"", cupsUser(), realm, nonce, resource, encode);
393 httpSetAuthString(http, "Digest", digest);
394 }
395
396 DEBUG_printf(("1cupsDoAuthentication: authstring=\"%s\"", http->authstring));
397
398 return (0);
399 }
400
401
402 #ifdef HAVE_GSSAPI
403 /*
404 * 'cups_get_gssname()' - Get CUPS service credentials for authentication.
405 */
406
407 static gss_name_t /* O - Server name */
cups_get_gssname(http_t * http,const char * service_name)408 cups_get_gssname(
409 http_t *http, /* I - Connection to server */
410 const char *service_name) /* I - Service name */
411 {
412 gss_buffer_desc token = GSS_C_EMPTY_BUFFER;
413 /* Service token */
414 OM_uint32 major_status, /* Major status code */
415 minor_status; /* Minor status code */
416 gss_name_t server_name; /* Server name */
417 char buf[1024], /* Name buffer */
418 fqdn[HTTP_MAX_URI]; /* Server name buffer */
419
420
421 DEBUG_printf(("7cups_get_gssname(http=%p, service_name=\"%s\")", http,
422 service_name));
423
424
425 /*
426 * Get the hostname...
427 */
428
429 httpGetHostname(http, fqdn, sizeof(fqdn));
430
431 if (!strcmp(fqdn, "localhost"))
432 httpGetHostname(NULL, fqdn, sizeof(fqdn));
433
434 /*
435 * Get a server name we can use for authentication purposes...
436 */
437
438 snprintf(buf, sizeof(buf), "%s@%s", service_name, fqdn);
439
440 DEBUG_printf(("9cups_get_gssname: Looking up %s...", buf));
441
442 token.value = buf;
443 token.length = strlen(buf);
444 server_name = GSS_C_NO_NAME;
445 major_status = gss_import_name(&minor_status, &token,
446 GSS_C_NT_HOSTBASED_SERVICE,
447 &server_name);
448
449 if (GSS_ERROR(major_status))
450 {
451 cups_gss_printf(major_status, minor_status,
452 "cups_get_gssname: gss_import_name() failed");
453 return (NULL);
454 }
455
456 return (server_name);
457 }
458
459
460 # ifdef DEBUG
461 /*
462 * 'cups_gss_printf()' - Show debug error messages from GSSAPI...
463 */
464
465 static void
cups_gss_printf(OM_uint32 major_status,OM_uint32 minor_status,const char * message)466 cups_gss_printf(OM_uint32 major_status,/* I - Major status code */
467 OM_uint32 minor_status,/* I - Minor status code */
468 const char *message) /* I - Prefix for error message */
469 {
470 OM_uint32 err_major_status, /* Major status code for display */
471 err_minor_status; /* Minor status code for display */
472 OM_uint32 msg_ctx; /* Message context */
473 gss_buffer_desc major_status_string = GSS_C_EMPTY_BUFFER,
474 /* Major status message */
475 minor_status_string = GSS_C_EMPTY_BUFFER;
476 /* Minor status message */
477
478
479 msg_ctx = 0;
480 err_major_status = gss_display_status(&err_minor_status,
481 major_status,
482 GSS_C_GSS_CODE,
483 GSS_C_NO_OID,
484 &msg_ctx,
485 &major_status_string);
486
487 if (!GSS_ERROR(err_major_status))
488 gss_display_status(&err_minor_status, minor_status, GSS_C_MECH_CODE,
489 GSS_C_NULL_OID, &msg_ctx, &minor_status_string);
490
491 DEBUG_printf(("1%s: %s, %s", message, (char *)major_status_string.value,
492 (char *)minor_status_string.value));
493
494 gss_release_buffer(&err_minor_status, &major_status_string);
495 gss_release_buffer(&err_minor_status, &minor_status_string);
496 }
497 # endif /* DEBUG */
498 #endif /* HAVE_GSSAPI */
499
500
501 /*
502 * 'cups_local_auth()' - Get the local authorization certificate if
503 * available/applicable...
504 */
505
506 static int /* O - 0 if available */
507 /* 1 if not available */
508 /* -1 error */
cups_local_auth(http_t * http)509 cups_local_auth(http_t *http) /* I - HTTP connection to server */
510 {
511 #if defined(WIN32) || defined(__EMX__)
512 /*
513 * Currently WIN32 and OS-2 do not support the CUPS server...
514 */
515
516 return (1);
517 #else
518 int pid; /* Current process ID */
519 FILE *fp; /* Certificate file */
520 char trc[16], /* Try Root Certificate parameter */
521 filename[1024], /* Certificate filename */
522 certificate[33];/* Certificate string */
523 _cups_globals_t *cg = _cupsGlobals(); /* Global data */
524 # if defined(HAVE_AUTHORIZATION_H)
525 OSStatus status; /* Status */
526 AuthorizationItem auth_right; /* Authorization right */
527 AuthorizationRights auth_rights; /* Authorization rights */
528 AuthorizationFlags auth_flags; /* Authorization flags */
529 AuthorizationExternalForm auth_extrn; /* Authorization ref external */
530 char auth_key[1024]; /* Buffer */
531 char buffer[1024]; /* Buffer */
532 # endif /* HAVE_AUTHORIZATION_H */
533
534
535 DEBUG_printf(("7cups_local_auth(http=%p) hostaddr=%s, hostname=\"%s\"",
536 http, httpAddrString(http->hostaddr, filename, sizeof(filename)), http->hostname));
537
538 /*
539 * See if we are accessing localhost...
540 */
541
542 if (!httpAddrLocalhost(http->hostaddr) &&
543 strcasecmp(http->hostname, "localhost") != 0)
544 {
545 DEBUG_puts("8cups_local_auth: Not a local connection!");
546 return (1);
547 }
548
549 # if defined(HAVE_AUTHORIZATION_H)
550 /*
551 * Delete any previous authorization reference...
552 */
553
554 if (http->auth_ref)
555 {
556 AuthorizationFree(http->auth_ref, kAuthorizationFlagDefaults);
557 http->auth_ref = NULL;
558 }
559
560 if (!getenv("GATEWAY_INTERFACE") &&
561 httpGetSubField2(http, HTTP_FIELD_WWW_AUTHENTICATE, "authkey",
562 auth_key, sizeof(auth_key)))
563 {
564 status = AuthorizationCreate(NULL, kAuthorizationEmptyEnvironment,
565 kAuthorizationFlagDefaults, &http->auth_ref);
566 if (status != errAuthorizationSuccess)
567 {
568 DEBUG_printf(("8cups_local_auth: AuthorizationCreate() returned %d (%s)",
569 (int)status, cssmErrorString(status)));
570 return (-1);
571 }
572
573 auth_right.name = auth_key;
574 auth_right.valueLength = 0;
575 auth_right.value = NULL;
576 auth_right.flags = 0;
577
578 auth_rights.count = 1;
579 auth_rights.items = &auth_right;
580
581 auth_flags = kAuthorizationFlagDefaults |
582 kAuthorizationFlagPreAuthorize |
583 kAuthorizationFlagInteractionAllowed |
584 kAuthorizationFlagExtendRights;
585
586 status = AuthorizationCopyRights(http->auth_ref, &auth_rights,
587 kAuthorizationEmptyEnvironment,
588 auth_flags, NULL);
589 if (status == errAuthorizationSuccess)
590 status = AuthorizationMakeExternalForm(http->auth_ref, &auth_extrn);
591
592 if (status == errAuthorizationSuccess)
593 {
594 /*
595 * Set the authorization string and return...
596 */
597
598 httpEncode64_2(buffer, sizeof(buffer), (void *)&auth_extrn,
599 sizeof(auth_extrn));
600
601 httpSetAuthString(http, "AuthRef", buffer);
602
603 DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
604 http->authstring));
605 return (0);
606 }
607 else if (status == errAuthorizationCanceled)
608 return (-1);
609
610 DEBUG_printf(("9cups_local_auth: AuthorizationCopyRights() returned %d (%s)",
611 (int)status, cssmErrorString(status)));
612
613 /*
614 * Fall through to try certificates...
615 */
616 }
617 # endif /* HAVE_AUTHORIZATION_H */
618
619 # if defined(SO_PEERCRED) && defined(AF_LOCAL)
620 /*
621 * See if we can authenticate using the peer credentials provided over a
622 * domain socket; if so, specify "PeerCred username" as the authentication
623 * information...
624 */
625
626 # ifdef HAVE_GSSAPI
627 if (strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9) &&
628 # else
629 if (
630 # endif /* HAVE_GSSAPI */
631 http->hostaddr->addr.sa_family == AF_LOCAL &&
632 !getenv("GATEWAY_INTERFACE")) /* Not via CGI programs... */
633 {
634 /*
635 * Verify that the current cupsUser() matches the current UID...
636 */
637
638 struct passwd *pwd; /* Password information */
639 const char *username; /* Current username */
640
641 username = cupsUser();
642
643 if ((pwd = getpwnam(username)) != NULL && pwd->pw_uid == getuid())
644 {
645 httpSetAuthString(http, "PeerCred", username);
646
647 DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
648 http->authstring));
649
650 return (0);
651 }
652 }
653 # endif /* SO_PEERCRED && AF_LOCAL */
654
655 /*
656 * Try opening a certificate file for this PID. If that fails,
657 * try the root certificate...
658 */
659
660 pid = getpid();
661 snprintf(filename, sizeof(filename), "%s/certs/%d", cg->cups_statedir, pid);
662 if ((fp = fopen(filename, "r")) == NULL && pid > 0)
663 {
664 /*
665 * No certificate for this PID; see if we can get the root certificate...
666 */
667
668 DEBUG_printf(("9cups_local_auth: Unable to open file %s: %s",
669 filename, strerror(errno)));
670
671 #ifdef HAVE_GSSAPI
672 if (!strncmp(http->fields[HTTP_FIELD_WWW_AUTHENTICATE], "Negotiate", 9))
673 {
674 /*
675 * Kerberos required, don't try the root certificate...
676 */
677
678 return (1);
679 }
680 #endif /* HAVE_GSSAPI */
681
682 if (!httpGetSubField2(http, HTTP_FIELD_WWW_AUTHENTICATE, "trc", trc,
683 sizeof(trc)))
684 {
685 /*
686 * Scheduler doesn't want us to use the root certificate...
687 */
688
689 return (1);
690 }
691
692 snprintf(filename, sizeof(filename), "%s/certs/0", cg->cups_statedir);
693 fp = fopen(filename, "r");
694 }
695
696 if (fp)
697 {
698 /*
699 * Read the certificate from the file...
700 */
701
702 fgets(certificate, sizeof(certificate), fp);
703 fclose(fp);
704
705 /*
706 * Set the authorization string and return...
707 */
708
709 httpSetAuthString(http, "Local", certificate);
710
711 DEBUG_printf(("8cups_local_auth: Returning authstring=\"%s\"",
712 http->authstring));
713
714 return (0);
715 }
716
717 return (1);
718 #endif /* WIN32 || __EMX__ */
719 }
720
721
722 /*
723 * End of "$Id: auth.c 9233 2010-08-10 06:15:55Z mike $".
724 */
725