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 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 bool inetd_server;
  46 static bool got_request;
  47
  48 static char *grab_line(FILE *f, int *cl)
  49 {
  50         char *ret = NULL;
  51         int i = 0;
  52         int len = 0;
  53
  54         while ((*cl)) {
  55                 int c;
  56
  57                 if (i == len) {
  58                         char *ret2;
  59                         if (len == 0) len = 1024;
  60                         else len *= 2;
  61                         ret2 = (char *)SMB_REALLOC_KEEP_OLD_ON_ERROR(ret, len);
  62                         if (!ret2) return ret;
  63                         ret = ret2;
  64                 }
  65
  66                 c = fgetc(f);
  67                 (*cl)--;
  68
  69                 if (c == EOF) {
  70                         (*cl) = 0;
  71                         break;
  72                 }
  73
  74                 if (c == '\r') continue;
  75
  76                 if (strchr_m("\n&", c)) break;
  77
  78                 ret[i++] = c;
  79
  80         }
  81
  82         if (ret) {
  83                 ret[i] = 0;
  84         }
  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                 char *saveptr;
 168                 for (tok=strtok_r(s, "&;", &saveptr); tok;
 169                      tok=strtok_r(NULL, "&;", &saveptr)) {
 170                         p = strchr_m(tok,'=');
 171                         if (!p) continue;
 172
 173                         *p = 0;
 174
 175                         variables[num_variables].name = SMB_STRDUP(tok);
 176                         variables[num_variables].value = SMB_STRDUP(p+1);
 177
 178                         if (!variables[num_variables].name ||
 179                             !variables[num_variables].value)
 180                                 continue;
 181
 182                         plus_to_space_unescape(variables[num_variables].value);
 183                         rfc1738_unescape(variables[num_variables].value);
 184                         plus_to_space_unescape(variables[num_variables].name);
 185                         rfc1738_unescape(variables[num_variables].name);
 186
 187 #ifdef DEBUG_COMMENTS
 188                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 189                                variables[num_variables].name,
 190                                variables[num_variables].value);
 191 #endif
 192                         num_variables++;
 193                         if (num_variables == MAX_VARIABLES) break;
 194                 }
 195
 196         }
 197 #ifdef DEBUG_COMMENTS
 198         printf("<!== End dump in cgi_load_variables() ==>\n");
 199 #endif
 200
 201         /* variables from the client are in UTF-8 - convert them
 202            to our internal unix charset before use */
 203         for (i=0;i<num_variables;i++) {
 204                 TALLOC_CTX *frame = talloc_stackframe();
 205                 char *dest = NULL;
 206                 size_t dest_len;
 207
 208                 convert_string_allocate(frame, CH_UTF8, CH_UNIX,
 209                                variables[i].name, strlen(variables[i].name),
 210                                &dest, &dest_len, True);
 211                 SAFE_FREE(variables[i].name);
 212                 variables[i].name = SMB_STRDUP(dest ? dest : "");
 213
 214                 dest = NULL;
 215                 convert_string_allocate(frame, CH_UTF8, CH_UNIX,
 216                                variables[i].value, strlen(variables[i].value),
 217                                &dest, &dest_len, True);
 218                 SAFE_FREE(variables[i].value);
 219                 variables[i].value = SMB_STRDUP(dest ? dest : "");
 220                 TALLOC_FREE(frame);
 221         }
 222 }
 223
 224
 225 /***************************************************************************
 226   find a variable passed via CGI
 227   Doesn't quite do what you think in the case of POST text variables, because
 228   if they exist they might have a value of "" or even " ", depending on the
 229   browser. Also doesn't allow for variables[] containing multiple variables
 230   with the same name and the same or different values.
 231   ***************************************************************************/
 232
 233 const char *cgi_variable(const char *name)
 234 {
 235         int i;
 236
 237         for (i=0;i<num_variables;i++)
 238                 if (strcmp(variables[i].name, name) == 0)
 239                         return variables[i].value;
 240         return NULL;
 241 }
 242
 243 /***************************************************************************
 244  Version of the above that can't return a NULL pointer.
 245 ***************************************************************************/
 246
 247 const char *cgi_variable_nonull(const char *name)
 248 {
 249         const char *var = cgi_variable(name);
 250         if (var) {
 251                 return var;
 252         } else {
 253                 return "";
 254         }
 255 }
 256
 257 /***************************************************************************
 258 tell a browser about a fatal error in the http processing
 259   ***************************************************************************/
 260 static void cgi_setup_error(const char *err, const char *header, const char *info)
 261 {
 262         if (!got_request) {
 263                 /* damn browsers don't like getting cut off before they give a request */
 264                 char line[1024];
 265                 while (fgets(line, sizeof(line)-1, stdin)) {
 266                         if (strnequal(line,"GET ", 4) ||
 267                             strnequal(line,"POST ", 5) ||
 268                             strnequal(line,"PUT ", 4)) {
 269                                 break;
 270                         }
 271                 }
 272         }
 273
 274         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);
 275         fclose(stdin);
 276         fclose(stdout);
 277         exit(0);
 278 }
 279
 280
 281 /***************************************************************************
 282 tell a browser about a fatal authentication error
 283   ***************************************************************************/
 284 static void cgi_auth_error(void)
 285 {
 286         if (inetd_server) {
 287                 cgi_setup_error("401 Authorization Required",
 288                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 289                                 "You must be authenticated to use this service");
 290         } else {
 291                 printf("Content-Type: text/html\r\n");
 292
 293                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 294                 printf("<BODY><H1>Installation Error</H1>\n");
 295                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 296                 printf("</BODY></HTML>\r\n");
 297         }
 298         exit(0);
 299 }
 300
 301 /***************************************************************************
 302 authenticate when we are running as a CGI
 303   ***************************************************************************/
 304 static void cgi_web_auth(void)
 305 {
 306         const char *user = getenv("REMOTE_USER");
 307         struct passwd *pwd;
 308         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 309         const char *tail = "</BODY></HTML>\r\n";
 310
 311         if (!user) {
 312                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 313                        head, tail);
 314                 exit(0);
 315         }
 316
 317         pwd = getpwnam_alloc(talloc_autofree_context(), user);
 318         if (!pwd) {
 319                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 320                 exit(0);
 321         }
 322
 323         setuid(0);
 324         setuid(pwd->pw_uid);
 325         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 326                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 327                        head, user, (int)geteuid(), (int)getuid(), tail);
 328                 exit(0);
 329         }
 330         TALLOC_FREE(pwd);
 331 }
 332
 333
 334 /***************************************************************************
 335 handle a http authentication line
 336   ***************************************************************************/
 337 static bool cgi_handle_authorization(char *line)
 338 {
 339         char *p;
 340         fstring user, user_pass;
 341         struct passwd *pass = NULL;
 342
 343         if (!strnequal(line,"Basic ", 6)) {
 344                 goto err;
 345         }
 346         line += 6;
 347         while (line[0] == ' ') line++;
 348         base64_decode_inplace(line);
 349         if (!(p=strchr_m(line,':'))) {
 350                 /*
 351                  * Always give the same error so a cracker
 352                  * cannot tell why we fail.
 353                  */
 354                 goto err;
 355         }
 356         *p = 0;
 357
 358         convert_string(CH_UTF8, CH_UNIX,
 359                        line, -1,
 360                        user, sizeof(user), True);
 361
 362         convert_string(CH_UTF8, CH_UNIX,
 363                        p+1, -1,
 364                        user_pass, sizeof(user_pass), True);
 365
 366         /*
 367          * Try and get the user from the UNIX password file.
 368          */
 369
 370         pass = getpwnam_alloc(talloc_autofree_context(), user);
 371
 372         /*
 373          * Validate the password they have given.
 374          */
 375
 376         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 377                       strlen(user_pass), NULL, False)) {
 378
 379                 if (pass) {
 380                         /*
 381                          * Password was ok.
 382                          */
 383
 384                         if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
 385                                 goto err;
 386
 387                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 388
 389                         /* Save the users name */
 390                         C_user = SMB_STRDUP(user);
 391                         TALLOC_FREE(pass);
 392                         return True;
 393                 }
 394         }
 395
 396 err:
 397         cgi_setup_error("401 Bad Authorization",
 398                         "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 399                         "username or password incorrect");
 400
 401         TALLOC_FREE(pass);
 402         return False;
 403 }
 404
 405 /***************************************************************************
 406 is this root?
 407   ***************************************************************************/
 408 bool am_root(void)
 409 {
 410         if (geteuid() == 0) {
 411                 return( True);
 412         } else {
 413                 return( False);
 414         }
 415 }
 416
 417 /***************************************************************************
 418 return a ptr to the users name
 419   ***************************************************************************/
 420 char *cgi_user_name(void)
 421 {
 422         return(C_user);
 423 }
 424
 425
 426 /***************************************************************************
 427 handle a file download
 428   ***************************************************************************/
 429 static void cgi_download(char *file)
 430 {
 431         SMB_STRUCT_STAT st;
 432         char buf[1024];
 433         int fd, l, i;
 434         char *p;
 435         char *lang;
 436
 437         /* sanitise the filename */
 438         for (i=0;file[i];i++) {
 439                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 440                         cgi_setup_error("404 File Not Found","",
 441                                         "Illegal character in filename");
 442                 }
 443         }
 444
 445         if (sys_stat(file, &st) != 0)
 446         {
 447                 cgi_setup_error("404 File Not Found","",
 448                                 "The requested file was not found");
 449         }
 450
 451         if (S_ISDIR(st.st_mode))
 452         {
 453                 snprintf(buf, sizeof(buf), "%s/index.html", file);
 454                 if (!file_exist(buf, &st) || !S_ISREG(st.st_mode))
 455                 {
 456                         cgi_setup_error("404 File Not Found","",
 457                                         "The requested file was not found");
 458                 }
 459         }
 460         else if (S_ISREG(st.st_mode))
 461         {
 462                 snprintf(buf, sizeof(buf), "%s", file);
 463         }
 464         else
 465         {
 466                 cgi_setup_error("404 File Not Found","",
 467                                 "The requested file was not found");
 468         }
 469
 470         fd = web_open(buf,O_RDONLY,0);
 471         if (fd == -1) {
 472                 cgi_setup_error("404 File Not Found","",
 473                                 "The requested file was not found");
 474         }
 475         printf("HTTP/1.0 200 OK\r\n");
 476         if ((p=strrchr_m(buf, '.'))) {
 477                 if (strcmp(p,".gif")==0) {
 478                         printf("Content-Type: image/gif\r\n");
 479                 } else if (strcmp(p,".jpg")==0) {
 480                         printf("Content-Type: image/jpeg\r\n");
 481                 } else if (strcmp(p,".png")==0) {
 482                         printf("Content-Type: image/png\r\n");
 483                 } else if (strcmp(p,".css")==0) {
 484                         printf("Content-Type: text/css\r\n");
 485                 } else if (strcmp(p,".txt")==0) {
 486                         printf("Content-Type: text/plain\r\n");
 487                 } else {
 488                         printf("Content-Type: text/html\r\n");
 489                 }
 490         }
 491         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 492
 493         lang = lang_tdb_current();
 494         if (lang) {
 495                 printf("Content-Language: %s\r\n", lang);
 496         }
 497
 498         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 499         while ((l=read(fd,buf,sizeof(buf)))>0) {
 500                 if (fwrite(buf, 1, l, stdout) != l) {
 501                         break;
 502                 }
 503         }
 504         close(fd);
 505         exit(0);
 506 }
 507
 508
 509
 510
 511 /**
 512  * @brief Setup the CGI framework.
 513  *
 514  * Setup the cgi framework, handling the possibility that this program
 515  * is either run as a true CGI program with a gateway to a web server, or
 516  * is itself a mini web server.
 517  **/
 518 void cgi_setup(const char *rootdir, int auth_required)
 519 {
 520         bool authenticated = False;
 521         char line[1024];
 522         char *url=NULL;
 523         char *p;
 524         char *lang;
 525
 526         if (chdir(rootdir)) {
 527                 cgi_setup_error("500 Server Error", "",
 528                                 "chdir failed - the server is not configured correctly");
 529         }
 530
 531         /* Handle the possibility we might be running as non-root */
 532         sec_init();
 533
 534         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 535                 /* if running as a cgi program */
 536                 web_set_lang(lang);
 537         }
 538
 539         /* maybe we are running under a web server */
 540         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 541                 if (auth_required) {
 542                         cgi_web_auth();
 543                 }
 544                 return;
 545         }
 546
 547         inetd_server = True;
 548
 549         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 550                 cgi_setup_error("403 Forbidden", "",
 551                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 552         }
 553
 554         /* we are a mini-web server. We need to read the request from stdin
 555            and handle authentication etc */
 556         while (fgets(line, sizeof(line)-1, stdin)) {
 557                 if (line[0] == '\r' || line[0] == '\n') break;
 558                 if (strnequal(line,"GET ", 4)) {
 559                         got_request = True;
 560                         url = SMB_STRDUP(&line[4]);
 561                 } else if (strnequal(line,"POST ", 5)) {
 562                         got_request = True;
 563                         request_post = 1;
 564                         url = SMB_STRDUP(&line[5]);
 565                 } else if (strnequal(line,"PUT ", 4)) {
 566                         got_request = True;
 567                         cgi_setup_error("400 Bad Request", "",
 568                                         "This server does not accept PUT requests");
 569                 } else if (strnequal(line,"Authorization: ", 15)) {
 570                         authenticated = cgi_handle_authorization(&line[15]);
 571                 } else if (strnequal(line,"Content-Length: ", 16)) {
 572                         content_length = atoi(&line[16]);
 573                 } else if (strnequal(line,"Accept-Language: ", 17)) {
 574                         web_set_lang(&line[17]);
 575                 }
 576                 /* ignore all other requests! */
 577         }
 578
 579         if (auth_required && !authenticated) {
 580                 cgi_auth_error();
 581         }
 582
 583         if (!url) {
 584                 cgi_setup_error("400 Bad Request", "",
 585                                 "You must specify a GET or POST request");
 586         }
 587
 588         /* trim the URL */
 589         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 590                 *p = 0;
 591         }
 592         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 593                 url[strlen(url)-1] = 0;
 594         }
 595
 596         /* anything following a ? in the URL is part of the query string */
 597         if ((p=strchr_m(url,'?'))) {
 598                 query_string = p+1;
 599                 *p = 0;
 600         }
 601
 602         string_sub(url, "/swat/", "", 0);
 603
 604         if (url[0] != '/' && strstr(url,"..")==0) {
 605                 cgi_download(url);
 606         }
 607
 608         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 609         printf("Date: %s\r\n", http_timestring(time(NULL)));
 610         baseurl = "";
 611         pathinfo = url+1;
 612 }
 613
 614
 615 /***************************************************************************
 616 return the current pages URL
 617   ***************************************************************************/
 618 const char *cgi_baseurl(void)
 619 {
 620         if (inetd_server) {
 621                 return baseurl;
 622         }
 623         return getenv("SCRIPT_NAME");
 624 }
 625
 626 /***************************************************************************
 627 return the current pages path info
 628   ***************************************************************************/
 629 const char *cgi_pathinfo(void)
 630 {
 631         char *r;
 632         if (inetd_server) {
 633                 return pathinfo;
 634         }
 635         r = getenv("PATH_INFO");
 636         if (!r) return "";
 637         if (*r == '/') r++;
 638         return r;
 639 }
 640
 641 /***************************************************************************
 642 return the hostname of the client
 643   ***************************************************************************/
 644 const char *cgi_remote_host(void)
 645 {
 646         if (inetd_server) {
 647                 return get_peer_name(1,False);
 648         }
 649         return getenv("REMOTE_HOST");
 650 }
 651
 652 /***************************************************************************
 653 return the hostname of the client
 654   ***************************************************************************/
 655 const char *cgi_remote_addr(void)
 656 {
 657         if (inetd_server) {
 658                 char addr[INET6_ADDRSTRLEN];
 659                 return get_peer_addr(1,addr,sizeof(addr));
 660         }
 661         return getenv("REMOTE_ADDR");
 662 }
 663
 664
 665 /***************************************************************************
 666 return True if the request was a POST
 667   ***************************************************************************/
 668 bool cgi_waspost(void)
 669 {
 670         if (inetd_server) {
 671                 return request_post;
 672         }
 673         return strequal(getenv("REQUEST_METHOD"), "POST");
 674 }