source: trunk/server/source3/web/cgi.c

Last change on this file was 862, checked in by Silvan Scherrer, 11 years ago

Samba Server: update trunk to 3.6.23
File size: 20.5 KB
RevLine 
[862]1/*
2 some simple CGI helper routines
3 Copyright (C) Andrew Tridgell 1997-1998
4
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 3 of the License, or
8 (at your option) any later version.
9
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
14
15 You should have received a copy of the GNU General Public License
16 along with this program. If not, see <http://www.gnu.org/licenses/>.
17*/
18
19
20#include "includes.h"
21#include "system/passwd.h"
22#include "system/filesys.h"
23#include "web/swat_proto.h"
24#include "intl/lang_tdb.h"
25#include "auth.h"
26#include "secrets.h"
27
28#define MAX_VARIABLES 10000
29
30/* set the expiry on fixed pages */
31#define EXPIRY_TIME (60*60*24*7)
32
33#ifdef DEBUG_COMMENTS
34extern void print_title(char *fmt, ...);
35#endif
36
37struct cgi_var {
38 char *name;
39 char *value;
40};
41
42static struct cgi_var variables[MAX_VARIABLES];
43static int num_variables;
44static int content_length;
45static int request_post;
46static char *query_string;
47static const char *baseurl;
48static char *pathinfo;
49static char *C_user;
50static char *C_pass;
51static char *C_nonce;
52static bool inetd_server;
53static bool got_request;
54
55static char *grab_line(FILE *f, int *cl)
56{
57 char *ret = NULL;
58 int i = 0;
59 int len = 0;
60
61 while ((*cl)) {
62 int c;
63
64 if (i == len) {
65 char *ret2;
66 if (len == 0) len = 1024;
67 else len *= 2;
68 ret2 = (char *)SMB_REALLOC_KEEP_OLD_ON_ERROR(ret, len);
69 if (!ret2) return ret;
70 ret = ret2;
71 }
72
73 c = fgetc(f);
74 (*cl)--;
75
76 if (c == EOF) {
77 (*cl) = 0;
78 break;
79 }
80
81 if (c == '\r') continue;
82
83 if (strchr_m("\n&", c)) break;
84
85 ret[i++] = c;
86
87 }
88
89 if (ret) {
90 ret[i] = 0;
91 }
92 return ret;
93}
94
95/**
96 URL encoded strings can have a '+', which should be replaced with a space
97
98 (This was in rfc1738_unescape(), but that broke the squid helper)
99**/
100
101static void plus_to_space_unescape(char *buf)
102{
103 char *p=buf;
104
105 while ((p=strchr_m(p,'+')))
106 *p = ' ';
107}
108
109/***************************************************************************
110 load all the variables passed to the CGI program. May have multiple variables
111 with the same name and the same or different values. Takes a file parameter
112 for simulating CGI invocation eg loading saved preferences.
113 ***************************************************************************/
114void cgi_load_variables(void)
115{
116 static char *line;
117 char *p, *s, *tok;
118 int len, i;
119 FILE *f = stdin;
120
121#ifdef DEBUG_COMMENTS
122 char dummy[100]="";
123 print_title(dummy);
124 d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
125#endif
126
127 if (!content_length) {
128 p = getenv("CONTENT_LENGTH");
129 len = p?atoi(p):0;
130 } else {
131 len = content_length;
132 }
133
134
135 if (len > 0 &&
136 (request_post ||
137 ((s=getenv("REQUEST_METHOD")) &&
138 strequal(s,"POST")))) {
139 while (len && (line=grab_line(f, &len))) {
140 p = strchr_m(line,'=');
141 if (!p) continue;
142
143 *p = 0;
144
145 variables[num_variables].name = SMB_STRDUP(line);
146 variables[num_variables].value = SMB_STRDUP(p+1);
147
148 SAFE_FREE(line);
149
150 if (!variables[num_variables].name ||
151 !variables[num_variables].value)
152 continue;
153
154 plus_to_space_unescape(variables[num_variables].value);
155 rfc1738_unescape(variables[num_variables].value);
156 plus_to_space_unescape(variables[num_variables].name);
157 rfc1738_unescape(variables[num_variables].name);
158
159#ifdef DEBUG_COMMENTS
160 printf("<!== POST var %s has value \"%s\" ==>\n",
161 variables[num_variables].name,
162 variables[num_variables].value);
163#endif
164
165 num_variables++;
166 if (num_variables == MAX_VARIABLES) break;
167 }
168 }
169
170 fclose(stdin);
171 open("/dev/null", O_RDWR);
172
173 if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
174 char *saveptr;
175 for (tok=strtok_r(s, "&;", &saveptr); tok;
176 tok=strtok_r(NULL, "&;", &saveptr)) {
177 p = strchr_m(tok,'=');
178 if (!p) continue;
179
180 *p = 0;
181
182 variables[num_variables].name = SMB_STRDUP(tok);
183 variables[num_variables].value = SMB_STRDUP(p+1);
184
185 if (!variables[num_variables].name ||
186 !variables[num_variables].value)
187 continue;
188
189 plus_to_space_unescape(variables[num_variables].value);
190 rfc1738_unescape(variables[num_variables].value);
191 plus_to_space_unescape(variables[num_variables].name);
192 rfc1738_unescape(variables[num_variables].name);
193
194#ifdef DEBUG_COMMENTS
195 printf("<!== Commandline var %s has value \"%s\" ==>\n",
196 variables[num_variables].name,
197 variables[num_variables].value);
198#endif
199 num_variables++;
200 if (num_variables == MAX_VARIABLES) break;
201 }
202
203 }
204#ifdef DEBUG_COMMENTS
205 printf("<!== End dump in cgi_load_variables() ==>\n");
206#endif
207
208 /* variables from the client are in UTF-8 - convert them
209 to our internal unix charset before use */
210 for (i=0;i<num_variables;i++) {
211 TALLOC_CTX *frame = talloc_stackframe();
212 char *dest = NULL;
213 size_t dest_len;
214
215 convert_string_talloc(frame, CH_UTF8, CH_UNIX,
216 variables[i].name, strlen(variables[i].name),
217 &dest, &dest_len, True);
218 SAFE_FREE(variables[i].name);
219 variables[i].name = SMB_STRDUP(dest ? dest : "");
220
221 dest = NULL;
222 convert_string_talloc(frame, CH_UTF8, CH_UNIX,
223 variables[i].value, strlen(variables[i].value),
224 &dest, &dest_len, True);
225 SAFE_FREE(variables[i].value);
226 variables[i].value = SMB_STRDUP(dest ? dest : "");
227 TALLOC_FREE(frame);
228 }
229}
230
231
232/***************************************************************************
233 find a variable passed via CGI
234 Doesn't quite do what you think in the case of POST text variables, because
235 if they exist they might have a value of "" or even " ", depending on the
236 browser. Also doesn't allow for variables[] containing multiple variables
237 with the same name and the same or different values.
238 ***************************************************************************/
239
240const char *cgi_variable(const char *name)
241{
242 int i;
243
244 for (i=0;i<num_variables;i++)
245 if (strcmp(variables[i].name, name) == 0)
246 return variables[i].value;
247 return NULL;
248}
249
250/***************************************************************************
251 Version of the above that can't return a NULL pointer.
252***************************************************************************/
253
254const char *cgi_variable_nonull(const char *name)
255{
256 const char *var = cgi_variable(name);
257 if (var) {
258 return var;
259 } else {
260 return "";
261 }
262}
263
264/***************************************************************************
265tell a browser about a fatal error in the http processing
266 ***************************************************************************/
267static void cgi_setup_error(const char *err, const char *header, const char *info)
268{
269 if (!got_request) {
270 /* damn browsers don't like getting cut off before they give a request */
271 char line[1024];
272 while (fgets(line, sizeof(line)-1, stdin)) {
273 if (strnequal(line,"GET ", 4) ||
274 strnequal(line,"POST ", 5) ||
275 strnequal(line,"PUT ", 4)) {
276 break;
277 }
278 }
279 }
280
281 d_printf("HTTP/1.0 %s\r\n%sConnection: close\r\nContent-Type: text/html\r\n\r\n<HTML><HEAD><TITLE>%s</TITLE></HEAD><BODY><H1>%s</H1>%s<p></BODY></HTML>\r\n\r\n", err, header, err, err, info);
282 fclose(stdin);
283 fclose(stdout);
284 exit(0);
285}
286
287
288/***************************************************************************
289tell a browser about a fatal authentication error
290 ***************************************************************************/
291static void cgi_auth_error(void)
292{
293 if (inetd_server) {
294 cgi_setup_error("401 Authorization Required",
295 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
296 "You must be authenticated to use this service");
297 } else {
298 printf("Content-Type: text/html\r\n");
299
300 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
301 printf("<BODY><H1>Installation Error</H1>\n");
302 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
303 printf("</BODY></HTML>\r\n");
304 }
305 exit(0);
306}
307
308/***************************************************************************
309authenticate when we are running as a CGI
310 ***************************************************************************/
311static void cgi_web_auth(void)
312{
313 const char *user = getenv("REMOTE_USER");
314 struct passwd *pwd;
315 const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
316 const char *tail = "</BODY></HTML>\r\n";
317
318 if (!user) {
319 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
320 head, tail);
321 exit(0);
322 }
323
324#ifndef __OS2__
325 pwd = Get_Pwnam_alloc(talloc_tos(), user);
326 if (!pwd) {
327 printf("%sCannot find user %s<br>%s\n", head, user, tail);
328 exit(0);
329 }
330
331 C_user = SMB_STRDUP(user);
332
333 if (!setuid(0)) {
334 C_pass = SMB_STRDUP(cgi_nonce());
335 }
336 setuid(pwd->pw_uid);
337 if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
338 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
339 head, user, (int)geteuid(), (int)getuid(), tail);
340 exit(0);
341 }
342 TALLOC_FREE(pwd);
343#endif
344}
345
346
347/***************************************************************************
348handle a http authentication line
349 ***************************************************************************/
350static bool cgi_handle_authorization(char *line)
351{
352 char *p;
353 fstring user, user_pass;
354 struct passwd *pass = NULL;
355 const char *rhost;
356 char addr[INET6_ADDRSTRLEN];
357
358 if (!strnequal(line,"Basic ", 6)) {
359 goto err;
360 }
361 line += 6;
362 while (line[0] == ' ') line++;
363 base64_decode_inplace(line);
364 if (!(p=strchr_m(line,':'))) {
365 /*
366 * Always give the same error so a cracker
367 * cannot tell why we fail.
368 */
369 goto err;
370 }
371 *p = 0;
372
373 convert_string(CH_UTF8, CH_UNIX,
374 line, -1,
375 user, sizeof(user), True);
376
377 convert_string(CH_UTF8, CH_UNIX,
378 p+1, -1,
379 user_pass, sizeof(user_pass), True);
380
381 /*
382 * Try and get the user from the UNIX password file.
383 */
384
385 pass = Get_Pwnam_alloc(talloc_tos(), user);
386
387 rhost = client_name(1);
388 if (strequal(rhost,"UNKNOWN"))
389 rhost = client_addr(1, addr, sizeof(addr));
390
391 /*
392 * Validate the password they have given.
393 */
394
395 if NT_STATUS_IS_OK(pass_check(pass, user, rhost, user_pass, false)) {
396 if (pass) {
397 /*
398 * Password was ok.
399 */
400
401 if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
402 goto err;
403
404 become_user_permanently(pass->pw_uid, pass->pw_gid);
405
406 /* Save the users name */
407 C_user = SMB_STRDUP(user);
408 C_pass = SMB_STRDUP(user_pass);
409 TALLOC_FREE(pass);
410 return True;
411 }
412 }
413
414err:
415 cgi_setup_error("401 Bad Authorization",
416 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
417 "username or password incorrect");
418
419 TALLOC_FREE(pass);
420 return False;
421}
422
423/***************************************************************************
424is this root?
425 ***************************************************************************/
426bool am_root(void)
427{
428 if (geteuid() == 0) {
429 return( True);
430 } else {
431 return( False);
432 }
433}
434
435/***************************************************************************
436return a ptr to the users name
437 ***************************************************************************/
438char *cgi_user_name(void)
439{
440 return(C_user);
441}
442
443/***************************************************************************
444return a ptr to the users password
445 ***************************************************************************/
446char *cgi_user_pass(void)
447{
448 return(C_pass);
449}
450
451/***************************************************************************
452return a ptr to the nonce
453 ***************************************************************************/
454char *cgi_nonce(void)
455{
456 const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
457 const char *tail = "</BODY></HTML>\r\n";
458 C_nonce = secrets_fetch_generic("root", "SWAT");
459 if (C_nonce == NULL) {
460 char *tmp_pass = NULL;
461 tmp_pass = generate_random_password(talloc_tos(),
462 16, 16);
463 if (tmp_pass == NULL) {
464 printf("%sFailed to create random nonce for "
465 "SWAT session\n<br>%s\n", head, tail);
466 exit(0);
467 }
468 secrets_store_generic("root", "SWAT", tmp_pass);
469 C_nonce = SMB_STRDUP(tmp_pass);
470 TALLOC_FREE(tmp_pass);
471 }
472 return(C_nonce);
473}
474
475/***************************************************************************
476handle a file download
477 ***************************************************************************/
478static void cgi_download(char *file)
479{
480 SMB_STRUCT_STAT st;
481 char buf[1024];
482 int fd, l, i;
483 char *p;
484 char *lang;
485
486 /* sanitise the filename */
487 for (i=0;file[i];i++) {
488 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
489 cgi_setup_error("404 File Not Found","",
490 "Illegal character in filename");
491 }
492 }
493
494 if (sys_stat(file, &st, false) != 0) {
495 cgi_setup_error("404 File Not Found","",
496 "The requested file was not found");
497 }
498
499 if (S_ISDIR(st.st_ex_mode))
500 {
501 snprintf(buf, sizeof(buf), "%s/index.html", file);
502 if (!file_exist_stat(buf, &st, false)
503 || !S_ISREG(st.st_ex_mode))
504 {
505 cgi_setup_error("404 File Not Found","",
506 "The requested file was not found");
507 }
508 }
509 else if (S_ISREG(st.st_ex_mode))
510 {
511 snprintf(buf, sizeof(buf), "%s", file);
512 }
513 else
514 {
515 cgi_setup_error("404 File Not Found","",
516 "The requested file was not found");
517 }
518
519 fd = web_open(buf,O_RDONLY,0);
520 if (fd == -1) {
521 cgi_setup_error("404 File Not Found","",
522 "The requested file was not found");
523 }
524 printf("HTTP/1.0 200 OK\r\n");
525 if ((p=strrchr_m(buf, '.'))) {
526 if (strcmp(p,".gif")==0) {
527 printf("Content-Type: image/gif\r\n");
528 } else if (strcmp(p,".jpg")==0) {
529 printf("Content-Type: image/jpeg\r\n");
530 } else if (strcmp(p,".png")==0) {
531 printf("Content-Type: image/png\r\n");
532 } else if (strcmp(p,".css")==0) {
533 printf("Content-Type: text/css\r\n");
534 } else if (strcmp(p,".txt")==0) {
535 printf("Content-Type: text/plain\r\n");
536 } else {
537 printf("Content-Type: text/html\r\n");
538 }
539 }
540 printf("Expires: %s\r\n",
541 http_timestring(talloc_tos(), time(NULL)+EXPIRY_TIME));
542
543 lang = lang_tdb_current();
544 if (lang) {
545 printf("Content-Language: %s\r\n", lang);
546 }
547
548 printf("Content-Length: %d\r\n\r\n", (int)st.st_ex_size);
549 while ((l=read(fd,buf,sizeof(buf)))>0) {
550 if (fwrite(buf, 1, l, stdout) != l) {
551 break;
552 }
553 }
554 close(fd);
555 exit(0);
556}
557
558
559
560/* return true if the char* contains ip addrs only. Used to avoid
561name lookup calls */
562
563static bool only_ipaddrs_in_list(const char **list)
564{
565 bool only_ip = true;
566
567 if (!list) {
568 return true;
569 }
570
571 for (; *list ; list++) {
572 /* factor out the special strings */
573 if (strequal(*list, "ALL") || strequal(*list, "FAIL") ||
574 strequal(*list, "EXCEPT")) {
575 continue;
576 }
577
578 if (!is_ipaddress(*list)) {
579 /*
580 * If we failed, make sure that it was not because
581 * the token was a network/netmask pair. Only
582 * network/netmask pairs have a '/' in them.
583 */
584 if ((strchr_m(*list, '/')) == NULL) {
585 only_ip = false;
586 DEBUG(3,("only_ipaddrs_in_list: list has "
587 "non-ip address (%s)\n",
588 *list));
589 break;
590 }
591 }
592 }
593
594 return only_ip;
595}
596
597/* return true if access should be allowed to a service for a socket */
598static bool check_access(int sock, const char **allow_list,
599 const char **deny_list)
600{
601 bool ret = false;
602 bool only_ip = false;
603 char addr[INET6_ADDRSTRLEN];
604
605 if ((!deny_list || *deny_list==0) && (!allow_list || *allow_list==0)) {
606 return true;
607 }
608
609 /* Bypass name resolution calls if the lists
610 * only contain IP addrs */
611 if (only_ipaddrs_in_list(allow_list) &&
612 only_ipaddrs_in_list(deny_list)) {
613 only_ip = true;
614 DEBUG (3, ("check_access: no hostnames "
615 "in host allow/deny list.\n"));
616 ret = allow_access(deny_list,
617 allow_list,
618 "",
619 get_peer_addr(sock,addr,sizeof(addr)));
620 } else {
621 DEBUG (3, ("check_access: hostnames in "
622 "host allow/deny list.\n"));
623 ret = allow_access(deny_list,
624 allow_list,
625 get_peer_name(sock,true),
626 get_peer_addr(sock,addr,sizeof(addr)));
627 }
628
629 if (ret) {
630 DEBUG(2,("Allowed connection from %s (%s)\n",
631 only_ip ? "" : get_peer_name(sock,true),
632 get_peer_addr(sock,addr,sizeof(addr))));
633 } else {
634 DEBUG(0,("Denied connection from %s (%s)\n",
635 only_ip ? "" : get_peer_name(sock,true),
636 get_peer_addr(sock,addr,sizeof(addr))));
637 }
638
639 return(ret);
640}
641
642/**
643 * @brief Setup the CGI framework.
644 *
645 * Setup the cgi framework, handling the possibility that this program
646 * is either run as a true CGI program with a gateway to a web server, or
647 * is itself a mini web server.
648 **/
649void cgi_setup(const char *rootdir, int auth_required)
650{
651 bool authenticated = False;
652 char line[1024];
653 char *url=NULL;
654 char *p;
655 char *lang;
656
657 if (chdir(rootdir)) {
658 cgi_setup_error("500 Server Error", "",
659 "chdir failed - the server is not configured correctly");
660 }
661
662 /* Handle the possibility we might be running as non-root */
663 sec_init();
664
665 if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
666 /* if running as a cgi program */
667 web_set_lang(lang);
668 }
669
670 /* maybe we are running under a web server */
671 if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
672 if (auth_required) {
673 cgi_web_auth();
674 }
675 return;
676 }
677
678 inetd_server = True;
679
680 if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
681 cgi_setup_error("403 Forbidden", "",
682 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
683 }
684
685 /* we are a mini-web server. We need to read the request from stdin
686 and handle authentication etc */
687 while (fgets(line, sizeof(line)-1, stdin)) {
688 if (line[0] == '\r' || line[0] == '\n') break;
689 if (strnequal(line,"GET ", 4)) {
690 got_request = True;
691 url = SMB_STRDUP(&line[4]);
692 } else if (strnequal(line,"POST ", 5)) {
693 got_request = True;
694 request_post = 1;
695 url = SMB_STRDUP(&line[5]);
696 } else if (strnequal(line,"PUT ", 4)) {
697 got_request = True;
698 cgi_setup_error("400 Bad Request", "",
699 "This server does not accept PUT requests");
700 } else if (strnequal(line,"Authorization: ", 15)) {
701 authenticated = cgi_handle_authorization(&line[15]);
702 } else if (strnequal(line,"Content-Length: ", 16)) {
703 content_length = atoi(&line[16]);
704 } else if (strnequal(line,"Accept-Language: ", 17)) {
705 web_set_lang(&line[17]);
706 }
707 /* ignore all other requests! */
708 }
709
710 if (auth_required && !authenticated) {
711 cgi_auth_error();
712 }
713
714 if (!url) {
715 cgi_setup_error("400 Bad Request", "",
716 "You must specify a GET or POST request");
717 }
718
719 /* trim the URL */
720 if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
721 *p = 0;
722 }
723 while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
724 url[strlen(url)-1] = 0;
725 }
726
727 /* anything following a ? in the URL is part of the query string */
728 if ((p=strchr_m(url,'?'))) {
729 query_string = p+1;
730 *p = 0;
731 }
732
733 string_sub(url, "/swat/", "", 0);
734
735 if (url[0] != '/' && strstr(url,"..")==0) {
736 cgi_download(url);
737 }
738
739 printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
740 printf("Date: %s\r\n", http_timestring(talloc_tos(), time(NULL)));
741 baseurl = "";
742 pathinfo = url+1;
743}
744
745
746/***************************************************************************
747return the current pages URL
748 ***************************************************************************/
749const char *cgi_baseurl(void)
750{
751 if (inetd_server) {
752 return baseurl;
753 }
754 return getenv("SCRIPT_NAME");
755}
756
757/***************************************************************************
758return the current pages path info
759 ***************************************************************************/
760const char *cgi_pathinfo(void)
761{
762 char *r;
763 if (inetd_server) {
764 return pathinfo;
765 }
766 r = getenv("PATH_INFO");
767 if (!r) return "";
768 if (*r == '/') r++;
769 return r;
770}
771
772/***************************************************************************
773return the hostname of the client
774 ***************************************************************************/
775const char *cgi_remote_host(void)
776{
777 if (inetd_server) {
778 return get_peer_name(1,False);
779 }
780 return getenv("REMOTE_HOST");
781}
782
783/***************************************************************************
784return the hostname of the client
785 ***************************************************************************/
786const char *cgi_remote_addr(void)
787{
788 if (inetd_server) {
789 char addr[INET6_ADDRSTRLEN];
790 get_peer_addr(1,addr,sizeof(addr));
791 return talloc_strdup(talloc_tos(), addr);
792 }
793 return getenv("REMOTE_ADDR");
794}
795
796
797/***************************************************************************
798return True if the request was a POST
799 ***************************************************************************/
800bool cgi_waspost(void)
801{
802 if (inetd_server) {
803 return request_post;
804 }
805 return strequal(getenv("REQUEST_METHOD"), "POST");
806}
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