source/web/cgi.c

   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 2 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, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20
  21 #include "includes.h"
  22 #include "../web/swat_proto.h"
  23
  24 #define MAX_VARIABLES 10000
  25
  26 /* set the expiry on fixed pages */
  27 #define EXPIRY_TIME (60*60*24*7)
  28
  29 #ifdef DEBUG_COMMENTS
  30 extern void print_title(char *fmt, ...);
  31 #endif
  32
  33 struct var {
  34         char *name;
  35         char *value;
  36 };
  37
  38 static struct var variables[MAX_VARIABLES];
  39 static int num_variables;
  40 static int content_length;
  41 static int request_post;
  42 static char *query_string;
  43 static const char *baseurl;
  44 static char *pathinfo;
  45 static char *C_user;
  46 static BOOL inetd_server;
  47 static BOOL got_request;
  48
  49 static char *grab_line(FILE *f, int *cl)
  50 {
  51         char *ret = NULL;
  52         int i = 0;
  53         int len = 0;
  54
  55         while ((*cl)) {
  56                 int c;
  57
  58                 if (i == len) {
  59                         char *ret2;
  60                         if (len == 0) len = 1024;
  61                         else len *= 2;
  62                         ret2 = (char *)Realloc(ret, len);
  63                         if (!ret2) return ret;
  64                         ret = ret2;
  65                 }
  66
  67                 c = fgetc(f);
  68                 (*cl)--;
  69
  70                 if (c == EOF) {
  71                         (*cl) = 0;
  72                         break;
  73                 }
  74
  75                 if (c == '\r') continue;
  76
  77                 if (strchr_m("\n&", c)) break;
  78
  79                 ret[i++] = c;
  80
  81         }
  82
  83
  84         ret[i] = 0;
  85         return ret;
  86 }
  87
  88 /***************************************************************************
  89   load all the variables passed to the CGI program. May have multiple variables
  90   with the same name and the same or different values. Takes a file parameter
  91   for simulating CGI invocation eg loading saved preferences.
  92   ***************************************************************************/
  93 void cgi_load_variables(void)
  94 {
  95         static char *line;
  96         char *p, *s, *tok;
  97         int len, i;
  98         FILE *f = stdin;
  99
 100 #ifdef DEBUG_COMMENTS
 101         char dummy[100]="";
 102         print_title(dummy);
 103         d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 104 #endif
 105
 106         if (!content_length) {
 107                 p = getenv("CONTENT_LENGTH");
 108                 len = p?atoi(p):0;
 109         } else {
 110                 len = content_length;
 111         }
 112
 113
 114         if (len > 0 &&
 115             (request_post ||
 116              ((s=getenv("REQUEST_METHOD")) &&
 117               strcasecmp(s,"POST")==0))) {
 118                 while (len && (line=grab_line(f, &len))) {
 119                         p = strchr_m(line,'=');
 120                         if (!p) continue;
 121
 122                         *p = 0;
 123
 124                         variables[num_variables].name = strdup(line);
 125                         variables[num_variables].value = strdup(p+1);
 126
 127                         SAFE_FREE(line);
 128
 129                         if (!variables[num_variables].name ||
 130                             !variables[num_variables].value)
 131                                 continue;
 132
 133                         rfc1738_unescape(variables[num_variables].value);
 134                         rfc1738_unescape(variables[num_variables].name);
 135
 136 #ifdef DEBUG_COMMENTS
 137                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 138                                variables[num_variables].name,
 139                                variables[num_variables].value);
 140 #endif
 141
 142                         num_variables++;
 143                         if (num_variables == MAX_VARIABLES) break;
 144                 }
 145         }
 146
 147         fclose(stdin);
 148         open("/dev/null", O_RDWR);
 149
 150         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 151                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 152                         p = strchr_m(tok,'=');
 153                         if (!p) continue;
 154
 155                         *p = 0;
 156
 157                         variables[num_variables].name = strdup(tok);
 158                         variables[num_variables].value = strdup(p+1);
 159
 160                         if (!variables[num_variables].name ||
 161                             !variables[num_variables].value)
 162                                 continue;
 163
 164                         rfc1738_unescape(variables[num_variables].value);
 165                         rfc1738_unescape(variables[num_variables].name);
 166
 167 #ifdef DEBUG_COMMENTS
 168                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 169                                variables[num_variables].name,
 170                                variables[num_variables].value);
 171 #endif
 172                         num_variables++;
 173                         if (num_variables == MAX_VARIABLES) break;
 174                 }
 175
 176         }
 177 #ifdef DEBUG_COMMENTS
 178         printf("<!== End dump in cgi_load_variables() ==>\n");
 179 #endif
 180
 181         /* variables from the client are in display charset - convert them
 182            to our internal charset before use */
 183         for (i=0;i<num_variables;i++) {
 184                 pstring dest;
 185
 186                 convert_string(CH_DISPLAY, CH_UNIX,
 187                                variables[i].name, -1,
 188                                dest, sizeof(dest));
 189                 free(variables[i].name);
 190                 variables[i].name = strdup(dest);
 191
 192                 convert_string(CH_DISPLAY, CH_UNIX,
 193                                variables[i].value, -1,
 194                                dest, sizeof(dest));
 195                 free(variables[i].value);
 196                 variables[i].value = strdup(dest);
 197         }
 198 }
 199
 200
 201 /***************************************************************************
 202   find a variable passed via CGI
 203   Doesn't quite do what you think in the case of POST text variables, because
 204   if they exist they might have a value of "" or even " ", depending on the
 205   browser. Also doesn't allow for variables[] containing multiple variables
 206   with the same name and the same or different values.
 207   ***************************************************************************/
 208 const char *cgi_variable(const char *name)
 209 {
 210         int i;
 211
 212         for (i=0;i<num_variables;i++)
 213                 if (strcmp(variables[i].name, name) == 0)
 214                         return variables[i].value;
 215         return NULL;
 216 }
 217
 218 /***************************************************************************
 219 tell a browser about a fatal error in the http processing
 220   ***************************************************************************/
 221 static void cgi_setup_error(const char *err, const char *header, const char *info)
 222 {
 223         if (!got_request) {
 224                 /* damn browsers don't like getting cut off before they give a request */
 225                 char line[1024];
 226                 while (fgets(line, sizeof(line)-1, stdin)) {
 227                         if (strncasecmp(line,"GET ", 4)==0 ||
 228                             strncasecmp(line,"POST ", 5)==0 ||
 229                             strncasecmp(line,"PUT ", 4)==0) {
 230                                 break;
 231                         }
 232                 }
 233         }
 234
 235         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);
 236         fclose(stdin);
 237         fclose(stdout);
 238         exit(0);
 239 }
 240
 241
 242 /***************************************************************************
 243 tell a browser about a fatal authentication error
 244   ***************************************************************************/
 245 static void cgi_auth_error(void)
 246 {
 247         if (inetd_server) {
 248                 cgi_setup_error("401 Authorization Required",
 249                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 250                                 "You must be authenticated to use this service");
 251         } else {
 252                 printf("Content-Type: text/html\r\n");
 253
 254                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 255                 printf("<BODY><H1>Installation Error</H1>\n");
 256                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 257                 printf("</BODY></HTML>\r\n");
 258         }
 259         exit(0);
 260 }
 261
 262 /***************************************************************************
 263 authenticate when we are running as a CGI
 264   ***************************************************************************/
 265 static void cgi_web_auth(void)
 266 {
 267         const char *user = getenv("REMOTE_USER");
 268         struct passwd *pwd;
 269         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 270         const char *tail = "</BODY></HTML>\r\n";
 271
 272         if (!user) {
 273                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 274                        head, tail);
 275                 exit(0);
 276         }
 277
 278         pwd = getpwnam_alloc(user);
 279         if (!pwd) {
 280                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 281                 exit(0);
 282         }
 283
 284         setuid(0);
 285         setuid(pwd->pw_uid);
 286         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 287                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 288                        head, user, (int)geteuid(), (int)getuid(), tail);
 289                 exit(0);
 290         }
 291         passwd_free(&pwd);
 292 }
 293
 294
 295 /***************************************************************************
 296 handle a http authentication line
 297   ***************************************************************************/
 298 static BOOL cgi_handle_authorization(char *line)
 299 {
 300         char *p;
 301         fstring user, user_pass;
 302         struct passwd *pass = NULL;
 303
 304         if (strncasecmp(line,"Basic ", 6)) {
 305                 goto err;
 306         }
 307         line += 6;
 308         while (line[0] == ' ') line++;
 309         base64_decode(line);
 310         if (!(p=strchr_m(line,':'))) {
 311                 /*
 312                  * Always give the same error so a cracker
 313                  * cannot tell why we fail.
 314                  */
 315                 goto err;
 316         }
 317         *p = 0;
 318
 319         convert_string(CH_DISPLAY, CH_UNIX,
 320                        line, -1,
 321                        user, sizeof(user));
 322
 323         convert_string(CH_DISPLAY, CH_UNIX,
 324                        p+1, -1,
 325                        user_pass, sizeof(user_pass));
 326
 327         /*
 328          * Try and get the user from the UNIX password file.
 329          */
 330
 331         pass = getpwnam_alloc(user);
 332
 333         /*
 334          * Validate the password they have given.
 335          */
 336
 337         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 338                       strlen(user_pass), NULL, False)) {
 339
 340                 if (pass) {
 341                         /*
 342                          * Password was ok.
 343                          */
 344
 345                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 346
 347                         /* Save the users name */
 348                         C_user = strdup(user);
 349                         passwd_free(&pass);
 350                         return True;
 351                 }
 352         }
 353
 354 err:
 355         cgi_setup_error("401 Bad Authorization", "",
 356                         "username or password incorrect");
 357
 358         passwd_free(&pass);
 359         return False;
 360 }
 361
 362 /***************************************************************************
 363 is this root?
 364   ***************************************************************************/
 365 BOOL am_root(void)
 366 {
 367         if (geteuid() == 0) {
 368                 return( True);
 369         } else {
 370                 return( False);
 371         }
 372 }
 373
 374 /***************************************************************************
 375 return a ptr to the users name
 376   ***************************************************************************/
 377 char *cgi_user_name(void)
 378 {
 379         return(C_user);
 380 }
 381
 382
 383 /***************************************************************************
 384 handle a file download
 385   ***************************************************************************/
 386 static void cgi_download(char *file)
 387 {
 388         SMB_STRUCT_STAT st;
 389         char buf[1024];
 390         int fd, l, i;
 391         char *p;
 392         char *lang;
 393
 394         /* sanitise the filename */
 395         for (i=0;file[i];i++) {
 396                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 397                         cgi_setup_error("404 File Not Found","",
 398                                         "Illegal character in filename");
 399                 }
 400         }
 401
 402         if (!file_exist(file, &st)) {
 403                 cgi_setup_error("404 File Not Found","",
 404                                 "The requested file was not found");
 405         }
 406
 407         fd = web_open(file,O_RDONLY,0);
 408         if (fd == -1) {
 409                 cgi_setup_error("404 File Not Found","",
 410                                 "The requested file was not found");
 411         }
 412         printf("HTTP/1.0 200 OK\r\n");
 413         if ((p=strrchr_m(file,'.'))) {
 414                 if (strcmp(p,".gif")==0) {
 415                         printf("Content-Type: image/gif\r\n");
 416                 } else if (strcmp(p,".jpg")==0) {
 417                         printf("Content-Type: image/jpeg\r\n");
 418                 } else if (strcmp(p,".txt")==0) {
 419                         printf("Content-Type: text/plain\r\n");
 420                 } else {
 421                         printf("Content-Type: text/html\r\n");
 422                 }
 423         }
 424         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 425
 426         lang = lang_tdb_current();
 427         if (lang) {
 428                 printf("Content-Language: %s\r\n", lang);
 429         }
 430
 431         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 432         while ((l=read(fd,buf,sizeof(buf)))>0) {
 433                 fwrite(buf, 1, l, stdout);
 434         }
 435         close(fd);
 436         exit(0);
 437 }
 438
 439
 440
 441
 442 /**
 443  * @brief Setup the CGI framework.
 444  *
 445  * Setup the cgi framework, handling the possibility that this program
 446  * is either run as a true CGI program with a gateway to a web server, or
 447  * is itself a mini web server.
 448  **/
 449 void cgi_setup(const char *rootdir, int auth_required)
 450 {
 451         BOOL authenticated = False;
 452         char line[1024];
 453         char *url=NULL;
 454         char *p;
 455         char *lang;
 456
 457         if (chdir(rootdir)) {
 458                 cgi_setup_error("400 Server Error", "",
 459                                 "chdir failed - the server is not configured correctly");
 460         }
 461
 462         /* Handle the possability we might be running as non-root */
 463         sec_init();
 464
 465         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 466                 /* if running as a cgi program */
 467                 web_set_lang(lang);
 468         }
 469
 470         /* maybe we are running under a web server */
 471         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 472                 if (auth_required) {
 473                         cgi_web_auth();
 474                 }
 475                 return;
 476         }
 477
 478         inetd_server = True;
 479
 480         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 481                 cgi_setup_error("400 Server Error", "",
 482                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 483         }
 484
 485         /* we are a mini-web server. We need to read the request from stdin
 486            and handle authentication etc */
 487         while (fgets(line, sizeof(line)-1, stdin)) {
 488                 if (line[0] == '\r' || line[0] == '\n') break;
 489                 if (strncasecmp(line,"GET ", 4)==0) {
 490                         got_request = True;
 491                         url = strdup(&line[4]);
 492                 } else if (strncasecmp(line,"POST ", 5)==0) {
 493                         got_request = True;
 494                         request_post = 1;
 495                         url = strdup(&line[5]);
 496                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 497                         got_request = True;
 498                         cgi_setup_error("400 Bad Request", "",
 499                                         "This server does not accept PUT requests");
 500                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 501                         authenticated = cgi_handle_authorization(&line[15]);
 502                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 503                         content_length = atoi(&line[16]);
 504                 } else if (strncasecmp(line,"Accept-Language: ", 17)==0) {
 505                         web_set_lang(&line[17]);
 506                 }
 507                 /* ignore all other requests! */
 508         }
 509
 510         if (auth_required && !authenticated) {
 511                 cgi_auth_error();
 512         }
 513
 514         if (!url) {
 515                 cgi_setup_error("400 Bad Request", "",
 516                                 "You must specify a GET or POST request");
 517         }
 518
 519         /* trim the URL */
 520         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 521                 *p = 0;
 522         }
 523         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 524                 url[strlen(url)-1] = 0;
 525         }
 526
 527         /* anything following a ? in the URL is part of the query string */
 528         if ((p=strchr_m(url,'?'))) {
 529                 query_string = p+1;
 530                 *p = 0;
 531         }
 532
 533         string_sub(url, "/swat/", "", 0);
 534
 535         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 536                 cgi_download(url);
 537         }
 538
 539         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 540         printf("Date: %s\r\n", http_timestring(time(NULL)));
 541         baseurl = "";
 542         pathinfo = url+1;
 543 }
 544
 545
 546 /***************************************************************************
 547 return the current pages URL
 548   ***************************************************************************/
 549 const char *cgi_baseurl(void)
 550 {
 551         if (inetd_server) {
 552                 return baseurl;
 553         }
 554         return getenv("SCRIPT_NAME");
 555 }
 556
 557 /***************************************************************************
 558 return the current pages path info
 559   ***************************************************************************/
 560 const char *cgi_pathinfo(void)
 561 {
 562         char *r;
 563         if (inetd_server) {
 564                 return pathinfo;
 565         }
 566         r = getenv("PATH_INFO");
 567         if (!r) return "";
 568         if (*r == '/') r++;
 569         return r;
 570 }
 571
 572 /***************************************************************************
 573 return the hostname of the client
 574   ***************************************************************************/
 575 char *cgi_remote_host(void)
 576 {
 577         if (inetd_server) {
 578                 return get_socket_name(1,False);
 579         }
 580         return getenv("REMOTE_HOST");
 581 }
 582
 583 /***************************************************************************
 584 return the hostname of the client
 585   ***************************************************************************/
 586 char *cgi_remote_addr(void)
 587 {
 588         if (inetd_server) {
 589                 return get_socket_addr(1);
 590         }
 591         return getenv("REMOTE_ADDR");
 592 }
 593
 594
 595 /***************************************************************************
 596 return True if the request was a POST
 597   ***************************************************************************/
 598 BOOL cgi_waspost(void)
 599 {
 600         if (inetd_server) {
 601                 return request_post;
 602         }
 603         return strequal(getenv("REQUEST_METHOD"), "POST");
 604 }