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 #include "secrets.h"
  23 #include "../lib/util/util.h"
  24
  25 #define MAX_VARIABLES 10000
  26
  27 /* set the expiry on fixed pages */
  28 #define EXPIRY_TIME (60*60*24*7)
  29
  30 #ifdef DEBUG_COMMENTS
  31 extern void print_title(char *fmt, ...);
  32 #endif
  33
  34 struct cgi_var {
  35         char *name;
  36         char *value;
  37 };
  38
  39 static struct cgi_var variables[MAX_VARIABLES];
  40 static int num_variables;
  41 static int content_length;
  42 static int request_post;
  43 static char *query_string;
  44 static const char *baseurl;
  45 static char *pathinfo;
  46 static char *C_user;
  47 static char *C_pass;
  48 static bool inetd_server;
  49 static bool got_request;
  50
  51 static char *grab_line(FILE *f, int *cl)
  52 {
  53         char *ret = NULL;
  54         int i = 0;
  55         int len = 0;
  56
  57         while ((*cl)) {
  58                 int c;
  59
  60                 if (i == len) {
  61                         char *ret2;
  62                         if (len == 0) len = 1024;
  63                         else len *= 2;
  64                         ret2 = (char *)SMB_REALLOC_KEEP_OLD_ON_ERROR(ret, len);
  65                         if (!ret2) return ret;
  66                         ret = ret2;
  67                 }
  68
  69                 c = fgetc(f);
  70                 (*cl)--;
  71
  72                 if (c == EOF) {
  73                         (*cl) = 0;
  74                         break;
  75                 }
  76
  77                 if (c == '\r') continue;
  78
  79                 if (strchr_m("\n&", c)) break;
  80
  81                 ret[i++] = c;
  82
  83         }
  84
  85         if (ret) {
  86                 ret[i] = 0;
  87         }
  88         return ret;
  89 }
  90
  91 /**
  92  URL encoded strings can have a '+', which should be replaced with a space
  93
  94  (This was in rfc1738_unescape(), but that broke the squid helper)
  95 **/
  96
  97 static void plus_to_space_unescape(char *buf)
  98 {
  99         char *p=buf;
 100
 101         while ((p=strchr_m(p,'+')))
 102                 *p = ' ';
 103 }
 104
 105 /***************************************************************************
 106   load all the variables passed to the CGI program. May have multiple variables
 107   with the same name and the same or different values. Takes a file parameter
 108   for simulating CGI invocation eg loading saved preferences.
 109   ***************************************************************************/
 110 void cgi_load_variables(void)
 111 {
 112         static char *line;
 113         char *p, *s, *tok;
 114         int len, i;
 115         FILE *f = stdin;
 116
 117 #ifdef DEBUG_COMMENTS
 118         char dummy[100]="";
 119         print_title(dummy);
 120         d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 121 #endif
 122
 123         if (!content_length) {
 124                 p = getenv("CONTENT_LENGTH");
 125                 len = p?atoi(p):0;
 126         } else {
 127                 len = content_length;
 128         }
 129
 130
 131         if (len > 0 &&
 132             (request_post ||
 133              ((s=getenv("REQUEST_METHOD")) &&
 134               strequal(s,"POST")))) {
 135                 while (len && (line=grab_line(f, &len))) {
 136                         p = strchr_m(line,'=');
 137                         if (!p) continue;
 138
 139                         *p = 0;
 140
 141                         variables[num_variables].name = SMB_STRDUP(line);
 142                         variables[num_variables].value = SMB_STRDUP(p+1);
 143
 144                         SAFE_FREE(line);
 145
 146                         if (!variables[num_variables].name ||
 147                             !variables[num_variables].value)
 148                                 continue;
 149
 150                         plus_to_space_unescape(variables[num_variables].value);
 151                         rfc1738_unescape(variables[num_variables].value);
 152                         plus_to_space_unescape(variables[num_variables].name);
 153                         rfc1738_unescape(variables[num_variables].name);
 154
 155 #ifdef DEBUG_COMMENTS
 156                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 157                                variables[num_variables].name,
 158                                variables[num_variables].value);
 159 #endif
 160
 161                         num_variables++;
 162                         if (num_variables == MAX_VARIABLES) break;
 163                 }
 164         }
 165
 166         fclose(stdin);
 167         open("/dev/null", O_RDWR);
 168
 169         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 170                 char *saveptr;
 171                 for (tok=strtok_r(s, "&;", &saveptr); tok;
 172                      tok=strtok_r(NULL, "&;", &saveptr)) {
 173                         p = strchr_m(tok,'=');
 174                         if (!p) continue;
 175
 176                         *p = 0;
 177
 178                         variables[num_variables].name = SMB_STRDUP(tok);
 179                         variables[num_variables].value = SMB_STRDUP(p+1);
 180
 181                         if (!variables[num_variables].name ||
 182                             !variables[num_variables].value)
 183                                 continue;
 184
 185                         plus_to_space_unescape(variables[num_variables].value);
 186                         rfc1738_unescape(variables[num_variables].value);
 187                         plus_to_space_unescape(variables[num_variables].name);
 188                         rfc1738_unescape(variables[num_variables].name);
 189
 190 #ifdef DEBUG_COMMENTS
 191                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 192                                variables[num_variables].name,
 193                                variables[num_variables].value);
 194 #endif
 195                         num_variables++;
 196                         if (num_variables == MAX_VARIABLES) break;
 197                 }
 198
 199         }
 200 #ifdef DEBUG_COMMENTS
 201         printf("<!== End dump in cgi_load_variables() ==>\n");
 202 #endif
 203
 204         /* variables from the client are in UTF-8 - convert them
 205            to our internal unix charset before use */
 206         for (i=0;i<num_variables;i++) {
 207                 TALLOC_CTX *frame = talloc_stackframe();
 208                 char *dest = NULL;
 209                 size_t dest_len;
 210
 211                 convert_string_talloc(frame, CH_UTF8, CH_UNIX,
 212                                variables[i].name, strlen(variables[i].name),
 213                                &dest, &dest_len, True);
 214                 SAFE_FREE(variables[i].name);
 215                 variables[i].name = SMB_STRDUP(dest ? dest : "");
 216
 217                 dest = NULL;
 218                 convert_string_talloc(frame, CH_UTF8, CH_UNIX,
 219                                variables[i].value, strlen(variables[i].value),
 220                                &dest, &dest_len, True);
 221                 SAFE_FREE(variables[i].value);
 222                 variables[i].value = SMB_STRDUP(dest ? dest : "");
 223                 TALLOC_FREE(frame);
 224         }
 225 }
 226
 227
 228 /***************************************************************************
 229   find a variable passed via CGI
 230   Doesn't quite do what you think in the case of POST text variables, because
 231   if they exist they might have a value of "" or even " ", depending on the
 232   browser. Also doesn't allow for variables[] containing multiple variables
 233   with the same name and the same or different values.
 234   ***************************************************************************/
 235
 236 const char *cgi_variable(const char *name)
 237 {
 238         int i;
 239
 240         for (i=0;i<num_variables;i++)
 241                 if (strcmp(variables[i].name, name) == 0)
 242                         return variables[i].value;
 243         return NULL;
 244 }
 245
 246 /***************************************************************************
 247  Version of the above that can't return a NULL pointer.
 248 ***************************************************************************/
 249
 250 const char *cgi_variable_nonull(const char *name)
 251 {
 252         const char *var = cgi_variable(name);
 253         if (var) {
 254                 return var;
 255         } else {
 256                 return "";
 257         }
 258 }
 259
 260 /***************************************************************************
 261 tell a browser about a fatal error in the http processing
 262   ***************************************************************************/
 263 static void cgi_setup_error(const char *err, const char *header, const char *info)
 264 {
 265         if (!got_request) {
 266                 /* damn browsers don't like getting cut off before they give a request */
 267                 char line[1024];
 268                 while (fgets(line, sizeof(line)-1, stdin)) {
 269                         if (strnequal(line,"GET ", 4) ||
 270                             strnequal(line,"POST ", 5) ||
 271                             strnequal(line,"PUT ", 4)) {
 272                                 break;
 273                         }
 274                 }
 275         }
 276
 277         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);
 278         fclose(stdin);
 279         fclose(stdout);
 280         exit(0);
 281 }
 282
 283
 284 /***************************************************************************
 285 tell a browser about a fatal authentication error
 286   ***************************************************************************/
 287 static void cgi_auth_error(void)
 288 {
 289         if (inetd_server) {
 290                 cgi_setup_error("401 Authorization Required",
 291                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 292                                 "You must be authenticated to use this service");
 293         } else {
 294                 printf("Content-Type: text/html\r\n");
 295
 296                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 297                 printf("<BODY><H1>Installation Error</H1>\n");
 298                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 299                 printf("</BODY></HTML>\r\n");
 300         }
 301         exit(0);
 302 }
 303
 304 /***************************************************************************
 305 authenticate when we are running as a CGI
 306   ***************************************************************************/
 307 static void cgi_web_auth(void)
 308 {
 309         const char *user = getenv("REMOTE_USER");
 310         struct passwd *pwd;
 311         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 312         const char *tail = "</BODY></HTML>\r\n";
 313
 314         if (!user) {
 315                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 316                        head, tail);
 317                 exit(0);
 318         }
 319
 320         pwd = Get_Pwnam_alloc(talloc_autofree_context(), user);
 321         if (!pwd) {
 322                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 323                 exit(0);
 324         }
 325
 326         C_user = SMB_STRDUP(user);
 327
 328         if (!setuid(0)) {
 329                 C_pass = secrets_fetch_generic("root", "SWAT");
 330                 if (C_pass == NULL) {
 331                         char *tmp_pass = NULL;
 332                         tmp_pass = generate_random_str(talloc_tos(), 16);
 333                         if (tmp_pass == NULL) {
 334                                 printf("%sFailed to create random nonce for "
 335                                        "SWAT session\n<br>%s\n", head, tail);
 336                                 exit(0);
 337                         }
 338                         secrets_store_generic("root", "SWAT", tmp_pass);
 339                         C_pass = SMB_STRDUP(tmp_pass);
 340                         TALLOC_FREE(tmp_pass);
 341                 }
 342         }
 343         setuid(pwd->pw_uid);
 344         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 345                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 346                        head, user, (int)geteuid(), (int)getuid(), tail);
 347                 exit(0);
 348         }
 349         TALLOC_FREE(pwd);
 350 }
 351
 352
 353 /***************************************************************************
 354 handle a http authentication line
 355   ***************************************************************************/
 356 static bool cgi_handle_authorization(char *line)
 357 {
 358         char *p;
 359         fstring user, user_pass;
 360         struct passwd *pass = NULL;
 361
 362         if (!strnequal(line,"Basic ", 6)) {
 363                 goto err;
 364         }
 365         line += 6;
 366         while (line[0] == ' ') line++;
 367         base64_decode_inplace(line);
 368         if (!(p=strchr_m(line,':'))) {
 369                 /*
 370                  * Always give the same error so a cracker
 371                  * cannot tell why we fail.
 372                  */
 373                 goto err;
 374         }
 375         *p = 0;
 376
 377         convert_string(CH_UTF8, CH_UNIX,
 378                        line, -1,
 379                        user, sizeof(user), True);
 380
 381         convert_string(CH_UTF8, CH_UNIX,
 382                        p+1, -1,
 383                        user_pass, sizeof(user_pass), True);
 384
 385         /*
 386          * Try and get the user from the UNIX password file.
 387          */
 388
 389         pass = Get_Pwnam_alloc(talloc_autofree_context(), user);
 390
 391         /*
 392          * Validate the password they have given.
 393          */
 394
 395         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 396                       strlen(user_pass), NULL, False)) {
 397
 398                 if (pass) {
 399                         /*
 400                          * Password was ok.
 401                          */
 402
 403                         if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
 404                                 goto err;
 405
 406                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 407
 408                         /* Save the users name */
 409                         C_user = SMB_STRDUP(user);
 410                         C_pass = SMB_STRDUP(user_pass);
 411                         TALLOC_FREE(pass);
 412                         return True;
 413                 }
 414         }
 415
 416 err:
 417         cgi_setup_error("401 Bad Authorization",
 418                         "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 419                         "username or password incorrect");
 420
 421         TALLOC_FREE(pass);
 422         return False;
 423 }
 424
 425 /***************************************************************************
 426 is this root?
 427   ***************************************************************************/
 428 bool am_root(void)
 429 {
 430         if (geteuid() == 0) {
 431                 return( True);
 432         } else {
 433                 return( False);
 434         }
 435 }
 436
 437 /***************************************************************************
 438 return a ptr to the users name
 439   ***************************************************************************/
 440 char *cgi_user_name(void)
 441 {
 442         return(C_user);
 443 }
 444
 445 /***************************************************************************
 446 return a ptr to the users password
 447   ***************************************************************************/
 448 char *cgi_user_pass(void)
 449 {
 450         return(C_pass);
 451 }
 452
 453 /***************************************************************************
 454 handle a file download
 455   ***************************************************************************/
 456 static void cgi_download(char *file)
 457 {
 458         SMB_STRUCT_STAT st;
 459         char buf[1024];
 460         int fd, l, i;
 461         char *p;
 462         char *lang;
 463
 464         /* sanitise the filename */
 465         for (i=0;file[i];i++) {
 466                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 467                         cgi_setup_error("404 File Not Found","",
 468                                         "Illegal character in filename");
 469                 }
 470         }
 471
 472         if (sys_stat(file, &st, false) != 0)    {
 473                 cgi_setup_error("404 File Not Found","",
 474                                 "The requested file was not found");
 475         }
 476
 477         if (S_ISDIR(st.st_ex_mode))
 478         {
 479                 snprintf(buf, sizeof(buf), "%s/index.html", file);
 480                 if (!file_exist_stat(buf, &st, false)
 481                     || !S_ISREG(st.st_ex_mode))
 482                 {
 483                         cgi_setup_error("404 File Not Found","",
 484                                         "The requested file was not found");
 485                 }
 486         }
 487         else if (S_ISREG(st.st_ex_mode))
 488         {
 489                 snprintf(buf, sizeof(buf), "%s", file);
 490         }
 491         else
 492         {
 493                 cgi_setup_error("404 File Not Found","",
 494                                 "The requested file was not found");
 495         }
 496
 497         fd = web_open(buf,O_RDONLY,0);
 498         if (fd == -1) {
 499                 cgi_setup_error("404 File Not Found","",
 500                                 "The requested file was not found");
 501         }
 502         printf("HTTP/1.0 200 OK\r\n");
 503         if ((p=strrchr_m(buf, '.'))) {
 504                 if (strcmp(p,".gif")==0) {
 505                         printf("Content-Type: image/gif\r\n");
 506                 } else if (strcmp(p,".jpg")==0) {
 507                         printf("Content-Type: image/jpeg\r\n");
 508                 } else if (strcmp(p,".png")==0) {
 509                         printf("Content-Type: image/png\r\n");
 510                 } else if (strcmp(p,".css")==0) {
 511                         printf("Content-Type: text/css\r\n");
 512                 } else if (strcmp(p,".txt")==0) {
 513                         printf("Content-Type: text/plain\r\n");
 514                 } else {
 515                         printf("Content-Type: text/html\r\n");
 516                 }
 517         }
 518         printf("Expires: %s\r\n",
 519                    http_timestring(talloc_tos(), time(NULL)+EXPIRY_TIME));
 520
 521         lang = lang_tdb_current();
 522         if (lang) {
 523                 printf("Content-Language: %s\r\n", lang);
 524         }
 525
 526         printf("Content-Length: %d\r\n\r\n", (int)st.st_ex_size);
 527         while ((l=read(fd,buf,sizeof(buf)))>0) {
 528                 if (fwrite(buf, 1, l, stdout) != l) {
 529                         break;
 530                 }
 531         }
 532         close(fd);
 533         exit(0);
 534 }
 535
 536
 537
 538
 539 /**
 540  * @brief Setup the CGI framework.
 541  *
 542  * Setup the cgi framework, handling the possibility that this program
 543  * is either run as a true CGI program with a gateway to a web server, or
 544  * is itself a mini web server.
 545  **/
 546 void cgi_setup(const char *rootdir, int auth_required)
 547 {
 548         bool authenticated = False;
 549         char line[1024];
 550         char *url=NULL;
 551         char *p;
 552         char *lang;
 553
 554         if (chdir(rootdir)) {
 555                 cgi_setup_error("500 Server Error", "",
 556                                 "chdir failed - the server is not configured correctly");
 557         }
 558
 559         /* Handle the possibility we might be running as non-root */
 560         sec_init();
 561
 562         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 563                 /* if running as a cgi program */
 564                 web_set_lang(lang);
 565         }
 566
 567         /* maybe we are running under a web server */
 568         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 569                 if (auth_required) {
 570                         cgi_web_auth();
 571                 }
 572                 return;
 573         }
 574
 575         inetd_server = True;
 576
 577         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 578                 cgi_setup_error("403 Forbidden", "",
 579                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 580         }
 581
 582         /* we are a mini-web server. We need to read the request from stdin
 583            and handle authentication etc */
 584         while (fgets(line, sizeof(line)-1, stdin)) {
 585                 if (line[0] == '\r' || line[0] == '\n') break;
 586                 if (strnequal(line,"GET ", 4)) {
 587                         got_request = True;
 588                         url = SMB_STRDUP(&line[4]);
 589                 } else if (strnequal(line,"POST ", 5)) {
 590                         got_request = True;
 591                         request_post = 1;
 592                         url = SMB_STRDUP(&line[5]);
 593                 } else if (strnequal(line,"PUT ", 4)) {
 594                         got_request = True;
 595                         cgi_setup_error("400 Bad Request", "",
 596                                         "This server does not accept PUT requests");
 597                 } else if (strnequal(line,"Authorization: ", 15)) {
 598                         authenticated = cgi_handle_authorization(&line[15]);
 599                 } else if (strnequal(line,"Content-Length: ", 16)) {
 600                         content_length = atoi(&line[16]);
 601                 } else if (strnequal(line,"Accept-Language: ", 17)) {
 602                         web_set_lang(&line[17]);
 603                 }
 604                 /* ignore all other requests! */
 605         }
 606
 607         if (auth_required && !authenticated) {
 608                 cgi_auth_error();
 609         }
 610
 611         if (!url) {
 612                 cgi_setup_error("400 Bad Request", "",
 613                                 "You must specify a GET or POST request");
 614         }
 615
 616         /* trim the URL */
 617         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 618                 *p = 0;
 619         }
 620         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 621                 url[strlen(url)-1] = 0;
 622         }
 623
 624         /* anything following a ? in the URL is part of the query string */
 625         if ((p=strchr_m(url,'?'))) {
 626                 query_string = p+1;
 627                 *p = 0;
 628         }
 629
 630         string_sub(url, "/swat/", "", 0);
 631
 632         if (url[0] != '/' && strstr(url,"..")==0) {
 633                 cgi_download(url);
 634         }
 635
 636         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 637         printf("Date: %s\r\n", http_timestring(talloc_tos(), time(NULL)));
 638         baseurl = "";
 639         pathinfo = url+1;
 640 }
 641
 642
 643 /***************************************************************************
 644 return the current pages URL
 645   ***************************************************************************/
 646 const char *cgi_baseurl(void)
 647 {
 648         if (inetd_server) {
 649                 return baseurl;
 650         }
 651         return getenv("SCRIPT_NAME");
 652 }
 653
 654 /***************************************************************************
 655 return the current pages path info
 656   ***************************************************************************/
 657 const char *cgi_pathinfo(void)
 658 {
 659         char *r;
 660         if (inetd_server) {
 661                 return pathinfo;
 662         }
 663         r = getenv("PATH_INFO");
 664         if (!r) return "";
 665         if (*r == '/') r++;
 666         return r;
 667 }
 668
 669 /***************************************************************************
 670 return the hostname of the client
 671   ***************************************************************************/
 672 const char *cgi_remote_host(void)
 673 {
 674         if (inetd_server) {
 675                 return get_peer_name(1,False);
 676         }
 677         return getenv("REMOTE_HOST");
 678 }
 679
 680 /***************************************************************************
 681 return the hostname of the client
 682   ***************************************************************************/
 683 const char *cgi_remote_addr(void)
 684 {
 685         if (inetd_server) {
 686                 char addr[INET6_ADDRSTRLEN];
 687                 get_peer_addr(1,addr,sizeof(addr));
 688                 return talloc_strdup(talloc_tos(), addr);
 689         }
 690         return getenv("REMOTE_ADDR");
 691 }
 692
 693
 694 /***************************************************************************
 695 return True if the request was a POST
 696   ***************************************************************************/
 697 bool cgi_waspost(void)
 698 {
 699         if (inetd_server) {
 700                 return request_post;
 701         }
 702         return strequal(getenv("REQUEST_METHOD"), "POST");
 703 }