summaryrefslogtreecommitdiff
path: root/source3/web/cgi.c
blob: 07f84b2a61d967d94cc47c4323daa3d421d6c9ef (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
/* 
   some simple CGI helper routines
   Copyright (C) Andrew Tridgell 1997-1998
   
   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.
   
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
   
   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/


#include "includes.h"
#include "smb.h"

#define MAX_VARIABLES 10000

/* set the expiry on fixed pages */
#define EXPIRY_TIME (60*60*24*7)

#ifdef DEBUG_COMMENTS
extern void print_title(char *fmt, ...);
#endif

struct var {
	char *name;
	char *value;
};

static struct var variables[MAX_VARIABLES];
static int num_variables;
static int content_length;
static int request_post;
static char *query_string;
static char *baseurl;
static char *pathinfo;
static char *C_user;
static BOOL inetd_server;
static BOOL got_request;

static void unescape(char *buf)
{
	char *p=buf;

	while ((p=strchr(p,'+')))
		*p = ' ';

	p = buf;

	while (p && *p && (p=strchr(p,'%'))) {
		int c1 = p[1];
		int c2 = p[2];

		if (c1 >= '0' && c1 <= '9')
			c1 = c1 - '0';
		else if (c1 >= 'A' && c1 <= 'F')
			c1 = 10 + c1 - 'A';
		else if (c1 >= 'a' && c1 <= 'f')
			c1 = 10 + c1 - 'a';
		else {p++; continue;}

		if (c2 >= '0' && c2 <= '9')
			c2 = c2 - '0';
		else if (c2 >= 'A' && c2 <= 'F')
			c2 = 10 + c2 - 'A';
		else if (c2 >= 'a' && c2 <= 'f')
			c2 = 10 + c2 - 'a';
		else {p++; continue;}
			
		*p = (c1<<4) | c2;

		memcpy(p+1, p+3, strlen(p+3)+1);
		p++;
	}
}


static char *grab_line(FILE *f, int *cl)
{
	char *ret;
	int i = 0;
	int len = 1024;

	ret = (char *)malloc(len);
	if (!ret) return NULL;
	

	while ((*cl)) {
		int c = fgetc(f);
		(*cl)--;

		if (c == EOF) {
			(*cl) = 0;
			break;
		}
		
		if (c == '\r') continue;

		if (strchr("\n&", c)) break;

		ret[i++] = c;

		if (i == len-1) {
			char *ret2;
			ret2 = (char *)realloc(ret, len*2);
			if (!ret2) return ret;
			len *= 2;
			ret = ret2;
		}
	}
	

	ret[i] = 0;
	return ret;
}

/***************************************************************************
  load all the variables passed to the CGI program. May have multiple variables
  with the same name and the same or different values. Takes a file parameter
  for simulating CGI invocation eg loading saved preferences.
  ***************************************************************************/
void cgi_load_variables(FILE *f1)
{
	FILE *f = f1;
	static char *line;
	char *p, *s, *tok;
	int len;

#ifdef DEBUG_COMMENTS
	char dummy[100]="";
	print_title(dummy);
	printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
#endif

	if (!f1) {
		f = stdin;
		if (!content_length) {
			p = getenv("CONTENT_LENGTH");
			len = p?atoi(p):0;
		} else {
			len = content_length;
		}
	} else {
		fseek(f, 0, SEEK_END);
		len = ftell(f);
		fseek(f, 0, SEEK_SET);
	}


	if (len > 0 && 
	    (f1 || request_post ||
	     ((s=getenv("REQUEST_METHOD")) && 
	      strcasecmp(s,"POST")==0))) {
		while (len && (line=grab_line(f, &len))) {
			p = strchr(line,'=');
			if (!p) continue;
			
			*p = 0;
			
			variables[num_variables].name = strdup(line);
			variables[num_variables].value = strdup(p+1);

			free(line);
			
			if (!variables[num_variables].name || 
			    !variables[num_variables].value)
				continue;

			unescape(variables[num_variables].value);
			unescape(variables[num_variables].name);

#ifdef DEBUG_COMMENTS
			printf("<!== POST var %s has value \"%s\"  ==>\n",
			       variables[num_variables].name,
			       variables[num_variables].value);
#endif
			
			num_variables++;
			if (num_variables == MAX_VARIABLES) break;
		}
	}

	if (f1) {
#ifdef DEBUG_COMMENTS
	        printf("<!== End dump in cgi_load_variables() ==>\n"); 
#endif
		return;
	}

	fclose(stdin);
	open("/dev/null", O_RDWR);

	if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
		for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
			p = strchr(tok,'=');
			if (!p) continue;
			
			*p = 0;
			
			variables[num_variables].name = strdup(tok);
			variables[num_variables].value = strdup(p+1);

			if (!variables[num_variables].name || 
			    !variables[num_variables].value)
				continue;

			unescape(variables[num_variables].value);
			unescape(variables[num_variables].name);

#ifdef DEBUG_COMMENTS
                        printf("<!== Commandline var %s has value \"%s\"  ==>\n",
                               variables[num_variables].name,
                               variables[num_variables].value);
#endif						
			num_variables++;
			if (num_variables == MAX_VARIABLES) break;
		}

	}
#ifdef DEBUG_COMMENTS
        printf("<!== End dump in cgi_load_variables() ==>\n");   
#endif
}


/***************************************************************************
  find a variable passed via CGI
  Doesn't quite do what you think in the case of POST text variables, because
  if they exist they might have a value of "" or even " ", depending on the 
  browser. Also doesn't allow for variables[] containing multiple variables
  with the same name and the same or different values.
  ***************************************************************************/
char *cgi_variable(char *name)
{
	int i;

	for (i=0;i<num_variables;i++)
		if (strcmp(variables[i].name, name) == 0)
			return variables[i].value;
	return NULL;
}

/***************************************************************************
tell a browser about a fatal error in the http processing
  ***************************************************************************/
static void cgi_setup_error(char *err, char *header, char *info)
{
	if (!got_request) {
		/* damn browsers don't like getting cut off before they give a request */
		char line[1024];
		while (fgets(line, sizeof(line)-1, stdin)) {
			if (strncasecmp(line,"GET ", 4)==0 || 
			    strncasecmp(line,"POST ", 5)==0 ||
			    strncasecmp(line,"PUT ", 4)==0) {
				break;
			}
		}
	}

	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);
	fclose(stdin);
	fclose(stdout);
	exit(0);
}


/***************************************************************************
tell a browser about a fatal authentication error
  ***************************************************************************/
static void cgi_auth_error(void)
{
	if (inetd_server) {
                cgi_setup_error("401 Authorization Required", 
                                "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
                                "You must be authenticated to use this service");
	} else {
		printf("Content-Type: text/html\r\n");

		printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
		printf("<BODY><H1>Installation Error</H1>\n");
		printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
		printf("</BODY></HTML>\r\n");
	}
	exit(0);
}

/***************************************************************************
authenticate when we are running as a CGI
  ***************************************************************************/
static void cgi_web_auth(void)
{
	char *user = getenv("REMOTE_USER");
	struct passwd *pwd;
	char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
	char *tail = "</BODY></HTML>\r\n";

	if (!user) {
		printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
		       head, tail);
		exit(0);
	}

	pwd = getpwnam(user);
	if (!pwd) {
		printf("%sCannot find user %s<br>%s\n", head, user, tail);
		exit(0);
	}

	setuid(0);
	setuid(pwd->pw_uid);
	if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
		printf("%sFailed to become user %s - uid=%d/%d<br>%s\n", 
		       head, user, (int)geteuid(), (int)getuid(), tail);
		exit(0);
	}
}

/***************************************************************************
decode a base64 string in-place - simple and slow algorithm
  ***************************************************************************/
static void base64_decode(char *s)
{
	char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
	int bit_offset, byte_offset, idx, i, n;
	unsigned char *d = (unsigned char *)s;
	char *p;

	n=i=0;

	while (*s && (p=strchr(b64,*s))) {
		idx = (int)(p - b64);
		byte_offset = (i*6)/8;
		bit_offset = (i*6)%8;
		d[byte_offset] &= ~((1<<(8-bit_offset))-1);
		if (bit_offset < 3) {
			d[byte_offset] |= (idx << (2-bit_offset));
			n = byte_offset+1;
		} else {
			d[byte_offset] |= (idx >> (bit_offset-2));
			d[byte_offset+1] = 0;
			d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
			n = byte_offset+2;
		}
		s++; i++;
	}
	/* null terminate */
	d[n] = 0;
}

/***************************************************************************
handle a http authentication line
  ***************************************************************************/
static BOOL cgi_handle_authorization(char *line)
{
	char *p, *user, *user_pass;
	struct passwd *pass = NULL;
	BOOL got_name = False;
	BOOL tested_pass = False;
	fstring default_user_lookup;
	fstring default_user_pass;

	/* Dummy user lookup to take the same time as a valid user. */
	fstrcpy(default_user_lookup, "zzzz bibble");
	fstrcpy(default_user_pass, "123456789");

	if (strncasecmp(line,"Basic ", 6)) {
		goto err;
	}
	line += 6;
	while (line[0] == ' ') line++;
	base64_decode(line);
	if (!(p=strchr(line,':'))) {
		/*
		 * Always give the same error so a cracker
		 * cannot tell why we fail.
		 */
		goto err;
	}
	*p = 0;
	user = line;
	user_pass = p+1;

	/*
	 * Try and get the user from the UNIX password file.
	 */

	if(!(pass = Get_Pwnam(user,False))) {
		/*
		 * Always give the same error so a cracker
		 * cannot tell why we fail.
		 */
		got_name = True;
		goto err;
	}

	/*
	 * Validate the password they have given.
	 */

	tested_pass = True;

	if(pass_check(user, user_pass, strlen(user_pass), NULL, NULL) == True) {

		/*
		 * Password was ok.
		 */

		if(pass->pw_uid != 0) {
			/*
			 * We have not authenticated as root,
			 * become the user *permanently*.
			 */
			become_user_permanently(pass->pw_uid, pass->pw_gid);
		}

		/* Save the users name */
		C_user = strdup(user);
		return True;
	}

  err:

	/* Always take the same time. */
	if (!got_name)
		Get_Pwnam(default_user_lookup,False);

	if (!tested_pass)
		pass_check(default_user_lookup, default_user_pass,
					strlen(default_user_pass), NULL, NULL);

	cgi_setup_error("401 Bad Authorization", "", 
			"username or password incorrect");

	return False;
}

/***************************************************************************
is this root?
  ***************************************************************************/
BOOL am_root(void)
{
	if (geteuid() == 0) {
		return( True);
	} else {
		return( False);
	}
}

/***************************************************************************
return a ptr to the users name
  ***************************************************************************/
char *cgi_user_name(void)
{
        return(C_user);
}


/***************************************************************************
handle a file download
  ***************************************************************************/
static void cgi_download(char *file)
{
	SMB_STRUCT_STAT st;
	char buf[1024];
	int fd, l, i;
	char *p;

	/* sanitise the filename */
	for (i=0;file[i];i++) {
		if (!isalnum((int)file[i]) && !strchr("/.-_", file[i])) {
			cgi_setup_error("404 File Not Found","",
					"Illegal character in filename");
		}
	}

	if (!file_exist(file, &st)) {
		cgi_setup_error("404 File Not Found","",
				"The requested file was not found");
	}
	fd = sys_open(file,O_RDONLY,0);
	if (fd == -1) {
		cgi_setup_error("404 File Not Found","",
				"The requested file was not found");
	}
	printf("HTTP/1.0 200 OK\r\n");
	if ((p=strrchr(file,'.'))) {
		if (strcmp(p,".gif")==0) {
			printf("Content-Type: image/gif\r\n");
		} else if (strcmp(p,".jpg")==0) {
			printf("Content-Type: image/jpeg\r\n");
		} else if (strcmp(p,".txt")==0) {
			printf("Content-Type: text/plain\r\n");
		} else {
			printf("Content-Type: text/html\r\n");
		}
	}
	printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));

	printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
	while ((l=read(fd,buf,sizeof(buf)))>0) {
		fwrite(buf, 1, l, stdout);
	}
	close(fd);
	exit(0);
}




/***************************************************************************
setup the cgi framework, handling the possability that this program is either
run as a true cgi program by a web browser or is itself a mini web server
  ***************************************************************************/
void cgi_setup(char *rootdir, int auth_required)
{
	BOOL authenticated = False;
	char line[1024];
	char *url=NULL;
	char *p;

	if (chdir(rootdir)) {
		cgi_setup_error("400 Server Error", "",
				"chdir failed - the server is not configured correctly");
	}

	/* maybe we are running under a web server */
	if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
		if (auth_required) {
			cgi_web_auth();
		}
		return;
	}

	inetd_server = True;

	if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
		cgi_setup_error("400 Server Error", "",
				"Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
	}

	/* we are a mini-web server. We need to read the request from stdin
	   and handle authentication etc */
	while (fgets(line, sizeof(line)-1, stdin)) {
		if (line[0] == '\r' || line[0] == '\n') break;
		if (strncasecmp(line,"GET ", 4)==0) {
			got_request = True;
			url = strdup(&line[4]);
		} else if (strncasecmp(line,"POST ", 5)==0) {
			got_request = True;
			request_post = 1;
			url = strdup(&line[5]);
		} else if (strncasecmp(line,"PUT ", 4)==0) {
			got_request = True;
			cgi_setup_error("400 Bad Request", "",
					"This server does not accept PUT requests");
		} else if (strncasecmp(line,"Authorization: ", 15)==0) {
			authenticated = cgi_handle_authorization(&line[15]);
		} else if (strncasecmp(line,"Content-Length: ", 16)==0) {
			content_length = atoi(&line[16]);
		}
		/* ignore all other requests! */
	}

	if (auth_required && !authenticated) {
		cgi_auth_error();
	}

	if (!url) {
		cgi_setup_error("400 Bad Request", "",
				"You must specify a GET or POST request");
	}

	/* trim the URL */
	if ((p = strchr(url,' ')) || (p=strchr(url,'\t'))) {
		*p = 0;
	}
	while (*url && strchr("\r\n",url[strlen(url)-1])) {
		url[strlen(url)-1] = 0;
	}

	/* anything following a ? in the URL is part of the query string */
	if ((p=strchr(url,'?'))) {
		query_string = p+1;
		*p = 0;
	}

	string_sub(url, "/swat/", "", 0);

	if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
		cgi_download(url);
	}

	printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
	printf("Date: %s\r\n", http_timestring(time(NULL)));
	baseurl = "";
	pathinfo = url+1;
}


/***************************************************************************
return the current pages URL
  ***************************************************************************/
char *cgi_baseurl(void)
{
	if (inetd_server) {
		return baseurl;
	}
	return getenv("SCRIPT_NAME");
}

/***************************************************************************
return the current pages path info
  ***************************************************************************/
char *cgi_pathinfo(void)
{
	char *r;
	if (inetd_server) {
		return pathinfo;
	}
	r = getenv("PATH_INFO");
	if (!r) return "";
	if (*r == '/') r++;
	return r;
}

/***************************************************************************
return the hostname of the client
  ***************************************************************************/
char *cgi_remote_host(void)
{
	if (inetd_server) {
		return get_socket_name(1);
	}
	return getenv("REMOTE_HOST");
}

/***************************************************************************
return the hostname of the client
  ***************************************************************************/
char *cgi_remote_addr(void)
{
	if (inetd_server) {
		return get_socket_addr(1);
	}
	return getenv("REMOTE_ADDR");
}


/***************************************************************************
return True if the request was a POST
  ***************************************************************************/
BOOL cgi_waspost(void)
{
	if (inetd_server) {
		return request_post;
	}
	return strequal(getenv("REQUEST_METHOD"), "POST");
}