source3/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 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 "web/swat_proto.h"
  22
  23 #define MAX_VARIABLES 10000
  24
  25 /* set the expiry on fixed pages */
  26 #define EXPIRY_TIME (60*60*24*7)
  27
  28 #ifdef DEBUG_COMMENTS
  29 extern void print_title(char *fmt, ...);
  30 #endif
  31
  32 struct cgi_var {
  33         char *name;
  34         char *value;
  35 };
  36
  37 static struct cgi_var variables[MAX_VARIABLES];
  38 static int num_variables;
  39 static int content_length;
  40 static int request_post;
  41 static char *query_string;
  42 static const char *baseurl;
  43 static char *pathinfo;
  44 static char *C_user;
  45 static char *C_pass;
  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                 char *saveptr;
 169                 for (tok=strtok_r(s, "&;", &saveptr); tok;
 170                      tok=strtok_r(NULL, "&;", &saveptr)) {
 171                         p = strchr_m(tok,'=');
 172                         if (!p) continue;
 173
 174                         *p = 0;
 175
 176                         variables[num_variables].name = SMB_STRDUP(tok);
 177                         variables[num_variables].value = SMB_STRDUP(p+1);
 178
 179                         if (!variables[num_variables].name ||
 180                             !variables[num_variables].value)
 181                                 continue;
 182
 183                         plus_to_space_unescape(variables[num_variables].value);
 184                         rfc1738_unescape(variables[num_variables].value);
 185                         plus_to_space_unescape(variables[num_variables].name);
 186                         rfc1738_unescape(variables[num_variables].name);
 187
 188 #ifdef DEBUG_COMMENTS
 189                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 190                                variables[num_variables].name,
 191                                variables[num_variables].value);
 192 #endif
 193                         num_variables++;
 194                         if (num_variables == MAX_VARIABLES) break;
 195                 }
 196
 197         }
 198 #ifdef DEBUG_COMMENTS
 199         printf("<!== End dump in cgi_load_variables() ==>\n");
 200 #endif
 201
 202         /* variables from the client are in UTF-8 - convert them
 203            to our internal unix charset before use */
 204         for (i=0;i<num_variables;i++) {
 205                 TALLOC_CTX *frame = talloc_stackframe();
 206                 char *dest = NULL;
 207                 size_t dest_len;
 208
 209                 convert_string_allocate(frame, CH_UTF8, CH_UNIX,
 210                                variables[i].name, strlen(variables[i].name),
 211                                &dest, &dest_len, True);
 212                 SAFE_FREE(variables[i].name);
 213                 variables[i].name = SMB_STRDUP(dest ? dest : "");
 214
 215                 dest = NULL;
 216                 convert_string_allocate(frame, CH_UTF8, CH_UNIX,
 217                                variables[i].value, strlen(variables[i].value),
 218                                &dest, &dest_len, True);
 219                 SAFE_FREE(variables[i].value);
 220                 variables[i].value = SMB_STRDUP(dest ? dest : "");
 221                 TALLOC_FREE(frame);
 222         }
 223 }
 224
 225
 226 /***************************************************************************
 227   find a variable passed via CGI
 228   Doesn't quite do what you think in the case of POST text variables, because
 229   if they exist they might have a value of "" or even " ", depending on the
 230   browser. Also doesn't allow for variables[] containing multiple variables
 231   with the same name and the same or different values.
 232   ***************************************************************************/
 233
 234 const char *cgi_variable(const char *name)
 235 {
 236         int i;
 237
 238         for (i=0;i<num_variables;i++)
 239                 if (strcmp(variables[i].name, name) == 0)
 240                         return variables[i].value;
 241         return NULL;
 242 }
 243
 244 /***************************************************************************
 245  Version of the above that can't return a NULL pointer.
 246 ***************************************************************************/
 247
 248 const char *cgi_variable_nonull(const char *name)
 249 {
 250         const char *var = cgi_variable(name);
 251         if (var) {
 252                 return var;
 253         } else {
 254                 return "";
 255         }
 256 }
 257
 258 /***************************************************************************
 259 tell a browser about a fatal error in the http processing
 260   ***************************************************************************/
 261 static void cgi_setup_error(const char *err, const char *header, const char *info)
 262 {
 263         if (!got_request) {
 264                 /* damn browsers don't like getting cut off before they give a request */
 265                 char line[1024];
 266                 while (fgets(line, sizeof(line)-1, stdin)) {
 267                         if (strnequal(line,"GET ", 4) ||
 268                             strnequal(line,"POST ", 5) ||
 269                             strnequal(line,"PUT ", 4)) {
 270                                 break;
 271                         }
 272                 }
 273         }
 274
 275         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);
 276         fclose(stdin);
 277         fclose(stdout);
 278         exit(0);
 279 }
 280
 281
 282 /***************************************************************************
 283 tell a browser about a fatal authentication error
 284   ***************************************************************************/
 285 static void cgi_auth_error(void)
 286 {
 287         if (inetd_server) {
 288                 cgi_setup_error("401 Authorization Required",
 289                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 290                                 "You must be authenticated to use this service");
 291         } else {
 292                 printf("Content-Type: text/html\r\n");
 293
 294                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 295                 printf("<BODY><H1>Installation Error</H1>\n");
 296                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 297                 printf("</BODY></HTML>\r\n");
 298         }
 299         exit(0);
 300 }
 301
 302 /***************************************************************************
 303 authenticate when we are running as a CGI
 304   ***************************************************************************/
 305 static void cgi_web_auth(void)
 306 {
 307         const char *user = getenv("REMOTE_USER");
 308         struct passwd *pwd;
 309         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 310         const char *tail = "</BODY></HTML>\r\n";
 311
 312         if (!user) {
 313                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 314                        head, tail);
 315                 exit(0);
 316         }
 317
 318         pwd = getpwnam_alloc(talloc_autofree_context(), user);
 319         if (!pwd) {
 320                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 321                 exit(0);
 322         }
 323
 324         setuid(0);
 325         setuid(pwd->pw_uid);
 326         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 327                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 328                        head, user, (int)geteuid(), (int)getuid(), tail);
 329                 exit(0);
 330         }
 331         TALLOC_FREE(pwd);
 332 }
 333
 334
 335 /***************************************************************************
 336 handle a http authentication line
 337   ***************************************************************************/
 338 static bool cgi_handle_authorization(char *line)
 339 {
 340         char *p;
 341         fstring user, user_pass;
 342         struct passwd *pass = NULL;
 343
 344         if (!strnequal(line,"Basic ", 6)) {
 345                 goto err;
 346         }
 347         line += 6;
 348         while (line[0] == ' ') line++;
 349         base64_decode_inplace(line);
 350         if (!(p=strchr_m(line,':'))) {
 351                 /*
 352                  * Always give the same error so a cracker
 353                  * cannot tell why we fail.
 354                  */
 355                 goto err;
 356         }
 357         *p = 0;
 358
 359         convert_string(CH_UTF8, CH_UNIX,
 360                        line, -1,
 361                        user, sizeof(user), True);
 362
 363         convert_string(CH_UTF8, CH_UNIX,
 364                        p+1, -1,
 365                        user_pass, sizeof(user_pass), True);
 366
 367         /*
 368          * Try and get the user from the UNIX password file.
 369          */
 370
 371         pass = getpwnam_alloc(talloc_autofree_context(), user);
 372
 373         /*
 374          * Validate the password they have given.
 375          */
 376
 377         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 378                       strlen(user_pass), NULL, False)) {
 379
 380                 if (pass) {
 381                         /*
 382                          * Password was ok.
 383                          */
 384
 385                         if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
 386                                 goto err;
 387
 388                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 389
 390                         /* Save the users name */
 391                         C_user = SMB_STRDUP(user);
 392                         C_pass = SMB_STRDUP(user_pass);
 393                         TALLOC_FREE(pass);
 394                         return True;
 395                 }
 396         }
 397
 398 err:
 399         cgi_setup_error("401 Bad Authorization",
 400                         "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 401                         "username or password incorrect");
 402
 403         TALLOC_FREE(pass);
 404         return False;
 405 }
 406
 407 /***************************************************************************
 408 is this root?
 409   ***************************************************************************/
 410 bool am_root(void)
 411 {
 412         if (geteuid() == 0) {
 413                 return( True);
 414         } else {
 415                 return( False);
 416         }
 417 }
 418
 419 /***************************************************************************
 420 return a ptr to the users name
 421   ***************************************************************************/
 422 char *cgi_user_name(void)
 423 {
 424         return(C_user);
 425 }
 426
 427 /***************************************************************************
 428 return a ptr to the users password
 429   ***************************************************************************/
 430 char *cgi_user_pass(void)
 431 {
 432         return(C_pass);
 433 }
 434
 435 /***************************************************************************
 436 handle a file download
 437   ***************************************************************************/
 438 static void cgi_download(char *file)
 439 {
 440         SMB_STRUCT_STAT st;
 441         char buf[1024];
 442         int fd, l, i;
 443         char *p;
 444         char *lang;
 445
 446         /* sanitise the filename */
 447         for (i=0;file[i];i++) {
 448                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 449                         cgi_setup_error("404 File Not Found","",
 450                                         "Illegal character in filename");
 451                 }
 452         }
 453
 454         if (sys_stat(file, &st) != 0)
 455         {
 456                 cgi_setup_error("404 File Not Found","",
 457                                 "The requested file was not found");
 458         }
 459
 460         if (S_ISDIR(st.st_mode))
 461         {
 462                 snprintf(buf, sizeof(buf), "%s/index.html", file);
 463                 if (!file_exist_stat(buf, &st) || !S_ISREG(st.st_mode))
 464                 {
 465                         cgi_setup_error("404 File Not Found","",
 466                                         "The requested file was not found");
 467                 }
 468         }
 469         else if (S_ISREG(st.st_mode))
 470         {
 471                 snprintf(buf, sizeof(buf), "%s", file);
 472         }
 473         else
 474         {
 475                 cgi_setup_error("404 File Not Found","",
 476                                 "The requested file was not found");
 477         }
 478
 479         fd = web_open(buf,O_RDONLY,0);
 480         if (fd == -1) {
 481                 cgi_setup_error("404 File Not Found","",
 482                                 "The requested file was not found");
 483         }
 484         printf("HTTP/1.0 200 OK\r\n");
 485         if ((p=strrchr_m(buf, '.'))) {
 486                 if (strcmp(p,".gif")==0) {
 487                         printf("Content-Type: image/gif\r\n");
 488                 } else if (strcmp(p,".jpg")==0) {
 489                         printf("Content-Type: image/jpeg\r\n");
 490                 } else if (strcmp(p,".png")==0) {
 491                         printf("Content-Type: image/png\r\n");
 492                 } else if (strcmp(p,".css")==0) {
 493                         printf("Content-Type: text/css\r\n");
 494                 } else if (strcmp(p,".txt")==0) {
 495                         printf("Content-Type: text/plain\r\n");
 496                 } else {
 497                         printf("Content-Type: text/html\r\n");
 498                 }
 499         }
 500         printf("Expires: %s\r\n",
 501                    http_timestring(talloc_tos(), time(NULL)+EXPIRY_TIME));
 502
 503         lang = lang_tdb_current();
 504         if (lang) {
 505                 printf("Content-Language: %s\r\n", lang);
 506         }
 507
 508         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 509         while ((l=read(fd,buf,sizeof(buf)))>0) {
 510                 if (fwrite(buf, 1, l, stdout) != l) {
 511                         break;
 512                 }
 513         }
 514         close(fd);
 515         exit(0);
 516 }
 517
 518
 519
 520
 521 /**
 522  * @brief Setup the CGI framework.
 523  *
 524  * Setup the cgi framework, handling the possibility that this program
 525  * is either run as a true CGI program with a gateway to a web server, or
 526  * is itself a mini web server.
 527  **/
 528 void cgi_setup(const char *rootdir, int auth_required)
 529 {
 530         bool authenticated = False;
 531         char line[1024];
 532         char *url=NULL;
 533         char *p;
 534         char *lang;
 535
 536         if (chdir(rootdir)) {
 537                 cgi_setup_error("500 Server Error", "",
 538                                 "chdir failed - the server is not configured correctly");
 539         }
 540
 541         /* Handle the possibility we might be running as non-root */
 542         sec_init();
 543
 544         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 545                 /* if running as a cgi program */
 546                 web_set_lang(lang);
 547         }
 548
 549         /* maybe we are running under a web server */
 550         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 551                 if (auth_required) {
 552                         cgi_web_auth();
 553                 }
 554                 return;
 555         }
 556
 557         inetd_server = True;
 558
 559         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 560                 cgi_setup_error("403 Forbidden", "",
 561                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 562         }
 563
 564         /* we are a mini-web server. We need to read the request from stdin
 565            and handle authentication etc */
 566         while (fgets(line, sizeof(line)-1, stdin)) {
 567                 if (line[0] == '\r' || line[0] == '\n') break;
 568                 if (strnequal(line,"GET ", 4)) {
 569                         got_request = True;
 570                         url = SMB_STRDUP(&line[4]);
 571                 } else if (strnequal(line,"POST ", 5)) {
 572                         got_request = True;
 573                         request_post = 1;
 574                         url = SMB_STRDUP(&line[5]);
 575                 } else if (strnequal(line,"PUT ", 4)) {
 576                         got_request = True;
 577                         cgi_setup_error("400 Bad Request", "",
 578                                         "This server does not accept PUT requests");
 579                 } else if (strnequal(line,"Authorization: ", 15)) {
 580                         authenticated = cgi_handle_authorization(&line[15]);
 581                 } else if (strnequal(line,"Content-Length: ", 16)) {
 582                         content_length = atoi(&line[16]);
 583                 } else if (strnequal(line,"Accept-Language: ", 17)) {
 584                         web_set_lang(&line[17]);
 585                 }
 586                 /* ignore all other requests! */
 587         }
 588
 589         if (auth_required && !authenticated) {
 590                 cgi_auth_error();
 591         }
 592
 593         if (!url) {
 594                 cgi_setup_error("400 Bad Request", "",
 595                                 "You must specify a GET or POST request");
 596         }
 597
 598         /* trim the URL */
 599         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 600                 *p = 0;
 601         }
 602         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 603                 url[strlen(url)-1] = 0;
 604         }
 605
 606         /* anything following a ? in the URL is part of the query string */
 607         if ((p=strchr_m(url,'?'))) {
 608                 query_string = p+1;
 609                 *p = 0;
 610         }
 611
 612         string_sub(url, "/swat/", "", 0);
 613
 614         if (url[0] != '/' && strstr(url,"..")==0) {
 615                 cgi_download(url);
 616         }
 617
 618         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 619         printf("Date: %s\r\n", http_timestring(talloc_tos(), time(NULL)));
 620         baseurl = "";
 621         pathinfo = url+1;
 622 }
 623
 624
 625 /***************************************************************************
 626 return the current pages URL
 627   ***************************************************************************/
 628 const char *cgi_baseurl(void)
 629 {
 630         if (inetd_server) {
 631                 return baseurl;
 632         }
 633         return getenv("SCRIPT_NAME");
 634 }
 635
 636 /***************************************************************************
 637 return the current pages path info
 638   ***************************************************************************/
 639 const char *cgi_pathinfo(void)
 640 {
 641         char *r;
 642         if (inetd_server) {
 643                 return pathinfo;
 644         }
 645         r = getenv("PATH_INFO");
 646         if (!r) return "";
 647         if (*r == '/') r++;
 648         return r;
 649 }
 650
 651 /***************************************************************************
 652 return the hostname of the client
 653   ***************************************************************************/
 654 const char *cgi_remote_host(void)
 655 {
 656         if (inetd_server) {
 657                 return get_peer_name(1,False);
 658         }
 659         return getenv("REMOTE_HOST");
 660 }
 661
 662 /***************************************************************************
 663 return the hostname of the client
 664   ***************************************************************************/
 665 const char *cgi_remote_addr(void)
 666 {
 667         if (inetd_server) {
 668                 char addr[INET6_ADDRSTRLEN];
 669                 get_peer_addr(1,addr,sizeof(addr));
 670                 return talloc_strdup(talloc_tos(), addr);
 671         }
 672         return getenv("REMOTE_ADDR");
 673 }
 674
 675
 676 /***************************************************************************
 677 return True if the request was a POST
 678   ***************************************************************************/
 679 bool cgi_waspost(void)
 680 {
 681         if (inetd_server) {
 682                 return request_post;
 683         }
 684         return strequal(getenv("REQUEST_METHOD"), "POST");
 685 }