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 cgi_var {
  34         char *name;
  35         char *value;
  36 };
  37
  38 static struct cgi_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 *)SMB_REALLOC_KEEP_OLD_ON_ERROR(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         if (ret) {
  84                 ret[i] = 0;
  85         }
  86         return ret;
  87 }
  88
  89 /**
  90  URL encoded strings can have a '+', which should be replaced with a space
  91
  92  (This was in rfc1738_unescape(), but that broke the squid helper)
  93 **/
  94
  95 static void plus_to_space_unescape(char *buf)
  96 {
  97         char *p=buf;
  98
  99         while ((p=strchr_m(p,'+')))
 100                 *p = ' ';
 101 }
 102
 103 /***************************************************************************
 104   load all the variables passed to the CGI program. May have multiple variables
 105   with the same name and the same or different values. Takes a file parameter
 106   for simulating CGI invocation eg loading saved preferences.
 107   ***************************************************************************/
 108 void cgi_load_variables(void)
 109 {
 110         static char *line;
 111         char *p, *s, *tok;
 112         int len, i;
 113         FILE *f = stdin;
 114
 115 #ifdef DEBUG_COMMENTS
 116         char dummy[100]="";
 117         print_title(dummy);
 118         d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 119 #endif
 120
 121         if (!content_length) {
 122                 p = getenv("CONTENT_LENGTH");
 123                 len = p?atoi(p):0;
 124         } else {
 125                 len = content_length;
 126         }
 127
 128
 129         if (len > 0 &&
 130             (request_post ||
 131              ((s=getenv("REQUEST_METHOD")) &&
 132               strequal(s,"POST")))) {
 133                 while (len && (line=grab_line(f, &len))) {
 134                         p = strchr_m(line,'=');
 135                         if (!p) continue;
 136
 137                         *p = 0;
 138
 139                         variables[num_variables].name = SMB_STRDUP(line);
 140                         variables[num_variables].value = SMB_STRDUP(p+1);
 141
 142                         SAFE_FREE(line);
 143
 144                         if (!variables[num_variables].name ||
 145                             !variables[num_variables].value)
 146                                 continue;
 147
 148                         plus_to_space_unescape(variables[num_variables].value);
 149                         rfc1738_unescape(variables[num_variables].value);
 150                         plus_to_space_unescape(variables[num_variables].name);
 151                         rfc1738_unescape(variables[num_variables].name);
 152
 153 #ifdef DEBUG_COMMENTS
 154                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 155                                variables[num_variables].name,
 156                                variables[num_variables].value);
 157 #endif
 158
 159                         num_variables++;
 160                         if (num_variables == MAX_VARIABLES) break;
 161                 }
 162         }
 163
 164         fclose(stdin);
 165         open("/dev/null", O_RDWR);
 166
 167         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 168                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 169                         p = strchr_m(tok,'=');
 170                         if (!p) continue;
 171
 172                         *p = 0;
 173
 174                         variables[num_variables].name = SMB_STRDUP(tok);
 175                         variables[num_variables].value = SMB_STRDUP(p+1);
 176
 177                         if (!variables[num_variables].name ||
 178                             !variables[num_variables].value)
 179                                 continue;
 180
 181                         plus_to_space_unescape(variables[num_variables].value);
 182                         rfc1738_unescape(variables[num_variables].value);
 183                         plus_to_space_unescape(variables[num_variables].name);
 184                         rfc1738_unescape(variables[num_variables].name);
 185
 186 #ifdef DEBUG_COMMENTS
 187                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 188                                variables[num_variables].name,
 189                                variables[num_variables].value);
 190 #endif
 191                         num_variables++;
 192                         if (num_variables == MAX_VARIABLES) break;
 193                 }
 194
 195         }
 196 #ifdef DEBUG_COMMENTS
 197         printf("<!== End dump in cgi_load_variables() ==>\n");
 198 #endif
 199
 200         /* variables from the client are in UTF-8 - convert them
 201            to our internal unix charset before use */
 202         for (i=0;i<num_variables;i++) {
 203                 pstring dest;
 204
 205                 convert_string(CH_UTF8, CH_UNIX,
 206                                variables[i].name, -1,
 207                                dest, sizeof(dest), True);
 208                 free(variables[i].name);
 209                 variables[i].name = SMB_STRDUP(dest);
 210
 211                 convert_string(CH_UTF8, CH_UNIX,
 212                                variables[i].value, -1,
 213                                dest, sizeof(dest), True);
 214                 free(variables[i].value);
 215                 variables[i].value = SMB_STRDUP(dest);
 216         }
 217 }
 218
 219
 220 /***************************************************************************
 221   find a variable passed via CGI
 222   Doesn't quite do what you think in the case of POST text variables, because
 223   if they exist they might have a value of "" or even " ", depending on the
 224   browser. Also doesn't allow for variables[] containing multiple variables
 225   with the same name and the same or different values.
 226   ***************************************************************************/
 227
 228 const char *cgi_variable(const char *name)
 229 {
 230         int i;
 231
 232         for (i=0;i<num_variables;i++)
 233                 if (strcmp(variables[i].name, name) == 0)
 234                         return variables[i].value;
 235         return NULL;
 236 }
 237
 238 /***************************************************************************
 239  Version of the above that can't return a NULL pointer.
 240 ***************************************************************************/
 241
 242 const char *cgi_variable_nonull(const char *name)
 243 {
 244         const char *var = cgi_variable(name);
 245         if (var) {
 246                 return var;
 247         } else {
 248                 return "";
 249         }
 250 }
 251
 252 /***************************************************************************
 253 tell a browser about a fatal error in the http processing
 254   ***************************************************************************/
 255 static void cgi_setup_error(const char *err, const char *header, const char *info)
 256 {
 257         if (!got_request) {
 258                 /* damn browsers don't like getting cut off before they give a request */
 259                 char line[1024];
 260                 while (fgets(line, sizeof(line)-1, stdin)) {
 261                         if (strnequal(line,"GET ", 4) ||
 262                             strnequal(line,"POST ", 5) ||
 263                             strnequal(line,"PUT ", 4)) {
 264                                 break;
 265                         }
 266                 }
 267         }
 268
 269         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);
 270         fclose(stdin);
 271         fclose(stdout);
 272         exit(0);
 273 }
 274
 275
 276 /***************************************************************************
 277 tell a browser about a fatal authentication error
 278   ***************************************************************************/
 279 static void cgi_auth_error(void)
 280 {
 281         if (inetd_server) {
 282                 cgi_setup_error("401 Authorization Required",
 283                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 284                                 "You must be authenticated to use this service");
 285         } else {
 286                 printf("Content-Type: text/html\r\n");
 287
 288                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 289                 printf("<BODY><H1>Installation Error</H1>\n");
 290                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 291                 printf("</BODY></HTML>\r\n");
 292         }
 293         exit(0);
 294 }
 295
 296 /***************************************************************************
 297 authenticate when we are running as a CGI
 298   ***************************************************************************/
 299 static void cgi_web_auth(void)
 300 {
 301         const char *user = getenv("REMOTE_USER");
 302         struct passwd *pwd;
 303         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 304         const char *tail = "</BODY></HTML>\r\n";
 305
 306         if (!user) {
 307                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 308                        head, tail);
 309                 exit(0);
 310         }
 311
 312         pwd = getpwnam_alloc(NULL, user);
 313         if (!pwd) {
 314                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 315                 exit(0);
 316         }
 317
 318         setuid(0);
 319         setuid(pwd->pw_uid);
 320         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 321                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 322                        head, user, (int)geteuid(), (int)getuid(), tail);
 323                 exit(0);
 324         }
 325         TALLOC_FREE(pwd);
 326 }
 327
 328
 329 /***************************************************************************
 330 handle a http authentication line
 331   ***************************************************************************/
 332 static BOOL cgi_handle_authorization(char *line)
 333 {
 334         char *p;
 335         fstring user, user_pass;
 336         struct passwd *pass = NULL;
 337
 338         if (!strnequal(line,"Basic ", 6)) {
 339                 goto err;
 340         }
 341         line += 6;
 342         while (line[0] == ' ') line++;
 343         base64_decode_inplace(line);
 344         if (!(p=strchr_m(line,':'))) {
 345                 /*
 346                  * Always give the same error so a cracker
 347                  * cannot tell why we fail.
 348                  */
 349                 goto err;
 350         }
 351         *p = 0;
 352
 353         convert_string(CH_UTF8, CH_UNIX,
 354                        line, -1,
 355                        user, sizeof(user), True);
 356
 357         convert_string(CH_UTF8, CH_UNIX,
 358                        p+1, -1,
 359                        user_pass, sizeof(user_pass), True);
 360
 361         /*
 362          * Try and get the user from the UNIX password file.
 363          */
 364
 365         pass = getpwnam_alloc(NULL, user);
 366
 367         /*
 368          * Validate the password they have given.
 369          */
 370
 371         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 372                       strlen(user_pass), NULL, False)) {
 373
 374                 if (pass) {
 375                         /*
 376                          * Password was ok.
 377                          */
 378
 379                         if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
 380                                 goto err;
 381
 382                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 383
 384                         /* Save the users name */
 385                         C_user = SMB_STRDUP(user);
 386                         TALLOC_FREE(pass);
 387                         return True;
 388                 }
 389         }
 390
 391 err:
 392         cgi_setup_error("401 Bad Authorization",
 393                         "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 394                         "username or password incorrect");
 395
 396         TALLOC_FREE(pass);
 397         return False;
 398 }
 399
 400 /***************************************************************************
 401 is this root?
 402   ***************************************************************************/
 403 BOOL am_root(void)
 404 {
 405         if (geteuid() == 0) {
 406                 return( True);
 407         } else {
 408                 return( False);
 409         }
 410 }
 411
 412 /***************************************************************************
 413 return a ptr to the users name
 414   ***************************************************************************/
 415 char *cgi_user_name(void)
 416 {
 417         return(C_user);
 418 }
 419
 420
 421 /***************************************************************************
 422 handle a file download
 423   ***************************************************************************/
 424 static void cgi_download(char *file)
 425 {
 426         SMB_STRUCT_STAT st;
 427         char buf[1024];
 428         int fd, l, i;
 429         char *p;
 430         char *lang;
 431
 432         /* sanitise the filename */
 433         for (i=0;file[i];i++) {
 434                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 435                         cgi_setup_error("404 File Not Found","",
 436                                         "Illegal character in filename");
 437                 }
 438         }
 439
 440         if (sys_stat(file, &st) != 0)
 441         {
 442                 cgi_setup_error("404 File Not Found","",
 443                                 "The requested file was not found");
 444         }
 445
 446         if (S_ISDIR(st.st_mode))
 447         {
 448                 snprintf(buf, sizeof(buf), "%s/index.html", file);
 449                 if (!file_exist(buf, &st) || !S_ISREG(st.st_mode))
 450                 {
 451                         cgi_setup_error("404 File Not Found","",
 452                                         "The requested file was not found");
 453                 }
 454         }
 455         else if (S_ISREG(st.st_mode))
 456         {
 457                 snprintf(buf, sizeof(buf), "%s", file);
 458         }
 459         else
 460         {
 461                 cgi_setup_error("404 File Not Found","",
 462                                 "The requested file was not found");
 463         }
 464
 465         fd = web_open(buf,O_RDONLY,0);
 466         if (fd == -1) {
 467                 cgi_setup_error("404 File Not Found","",
 468                                 "The requested file was not found");
 469         }
 470         printf("HTTP/1.0 200 OK\r\n");
 471         if ((p=strrchr_m(buf, '.'))) {
 472                 if (strcmp(p,".gif")==0) {
 473                         printf("Content-Type: image/gif\r\n");
 474                 } else if (strcmp(p,".jpg")==0) {
 475                         printf("Content-Type: image/jpeg\r\n");
 476                 } else if (strcmp(p,".png")==0) {
 477                         printf("Content-Type: image/png\r\n");
 478                 } else if (strcmp(p,".css")==0) {
 479                         printf("Content-Type: text/css\r\n");
 480                 } else if (strcmp(p,".txt")==0) {
 481                         printf("Content-Type: text/plain\r\n");
 482                 } else {
 483                         printf("Content-Type: text/html\r\n");
 484                 }
 485         }
 486         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 487
 488         lang = lang_tdb_current();
 489         if (lang) {
 490                 printf("Content-Language: %s\r\n", lang);
 491         }
 492
 493         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 494         while ((l=read(fd,buf,sizeof(buf)))>0) {
 495                 fwrite(buf, 1, l, stdout);
 496         }
 497         close(fd);
 498         exit(0);
 499 }
 500
 501
 502
 503
 504 /**
 505  * @brief Setup the CGI framework.
 506  *
 507  * Setup the cgi framework, handling the possibility that this program
 508  * is either run as a true CGI program with a gateway to a web server, or
 509  * is itself a mini web server.
 510  **/
 511 void cgi_setup(const char *rootdir, int auth_required)
 512 {
 513         BOOL authenticated = False;
 514         char line[1024];
 515         char *url=NULL;
 516         char *p;
 517         char *lang;
 518
 519         if (chdir(rootdir)) {
 520                 cgi_setup_error("500 Server Error", "",
 521                                 "chdir failed - the server is not configured correctly");
 522         }
 523
 524         /* Handle the possibility we might be running as non-root */
 525         sec_init();
 526
 527         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 528                 /* if running as a cgi program */
 529                 web_set_lang(lang);
 530         }
 531
 532         /* maybe we are running under a web server */
 533         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 534                 if (auth_required) {
 535                         cgi_web_auth();
 536                 }
 537                 return;
 538         }
 539
 540         inetd_server = True;
 541
 542         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 543                 cgi_setup_error("403 Forbidden", "",
 544                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 545         }
 546
 547         /* we are a mini-web server. We need to read the request from stdin
 548            and handle authentication etc */
 549         while (fgets(line, sizeof(line)-1, stdin)) {
 550                 if (line[0] == '\r' || line[0] == '\n') break;
 551                 if (strnequal(line,"GET ", 4)) {
 552                         got_request = True;
 553                         url = SMB_STRDUP(&line[4]);
 554                 } else if (strnequal(line,"POST ", 5)) {
 555                         got_request = True;
 556                         request_post = 1;
 557                         url = SMB_STRDUP(&line[5]);
 558                 } else if (strnequal(line,"PUT ", 4)) {
 559                         got_request = True;
 560                         cgi_setup_error("400 Bad Request", "",
 561                                         "This server does not accept PUT requests");
 562                 } else if (strnequal(line,"Authorization: ", 15)) {
 563                         authenticated = cgi_handle_authorization(&line[15]);
 564                 } else if (strnequal(line,"Content-Length: ", 16)) {
 565                         content_length = atoi(&line[16]);
 566                 } else if (strnequal(line,"Accept-Language: ", 17)) {
 567                         web_set_lang(&line[17]);
 568                 }
 569                 /* ignore all other requests! */
 570         }
 571
 572         if (auth_required && !authenticated) {
 573                 cgi_auth_error();
 574         }
 575
 576         if (!url) {
 577                 cgi_setup_error("400 Bad Request", "",
 578                                 "You must specify a GET or POST request");
 579         }
 580
 581         /* trim the URL */
 582         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 583                 *p = 0;
 584         }
 585         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 586                 url[strlen(url)-1] = 0;
 587         }
 588
 589         /* anything following a ? in the URL is part of the query string */
 590         if ((p=strchr_m(url,'?'))) {
 591                 query_string = p+1;
 592                 *p = 0;
 593         }
 594
 595         string_sub(url, "/swat/", "", 0);
 596
 597         if (url[0] != '/' && strstr(url,"..")==0) {
 598                 cgi_download(url);
 599         }
 600
 601         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 602         printf("Date: %s\r\n", http_timestring(time(NULL)));
 603         baseurl = "";
 604         pathinfo = url+1;
 605 }
 606
 607
 608 /***************************************************************************
 609 return the current pages URL
 610   ***************************************************************************/
 611 const char *cgi_baseurl(void)
 612 {
 613         if (inetd_server) {
 614                 return baseurl;
 615         }
 616         return getenv("SCRIPT_NAME");
 617 }
 618
 619 /***************************************************************************
 620 return the current pages path info
 621   ***************************************************************************/
 622 const char *cgi_pathinfo(void)
 623 {
 624         char *r;
 625         if (inetd_server) {
 626                 return pathinfo;
 627         }
 628         r = getenv("PATH_INFO");
 629         if (!r) return "";
 630         if (*r == '/') r++;
 631         return r;
 632 }
 633
 634 /***************************************************************************
 635 return the hostname of the client
 636   ***************************************************************************/
 637 char *cgi_remote_host(void)
 638 {
 639         if (inetd_server) {
 640                 return get_peer_name(1,False);
 641         }
 642         return getenv("REMOTE_HOST");
 643 }
 644
 645 /***************************************************************************
 646 return the hostname of the client
 647   ***************************************************************************/
 648 char *cgi_remote_addr(void)
 649 {
 650         if (inetd_server) {
 651                 return get_peer_addr(1);
 652         }
 653         return getenv("REMOTE_ADDR");
 654 }
 655
 656
 657 /***************************************************************************
 658 return True if the request was a POST
 659   ***************************************************************************/
 660 BOOL cgi_waspost(void)
 661 {
 662         if (inetd_server) {
 663                 return request_post;
 664         }
 665         return strequal(getenv("REQUEST_METHOD"), "POST");
 666 }