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