source/web/cgi.c

   1 /*
   2    some simple CGI helper routines
   3    Copyright (C) Andrew Tridgell 1997-1998
   4
   5    This program is free software; you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20
  21 #include "includes.h"
  22 #include "web/swat_proto.h"
  23
  24 #define MAX_VARIABLES 10000
  25
  26 /* set the expiry on fixed pages */
  27 #define EXPIRY_TIME (60*60*24*7)
  28
  29 #ifdef DEBUG_COMMENTS
  30 extern void print_title(char *fmt, ...);
  31 #endif
  32
  33 struct cgi_var {
  34         char *name;
  35         char *value;
  36 };
  37
  38 static struct cgi_var variables[MAX_VARIABLES];
  39 static int num_variables;
  40 static int content_length;
  41 static int request_post;
  42 static char *query_string;
  43 static const char *baseurl;
  44 static char *pathinfo;
  45 static char *C_user;
  46 static BOOL inetd_server;
  47 static BOOL got_request;
  48
  49 static char *grab_line(FILE *f, int *cl)
  50 {
  51         char *ret = NULL;
  52         int i = 0;
  53         int len = 0;
  54
  55         while ((*cl)) {
  56                 int c;
  57
  58                 if (i == len) {
  59                         char *ret2;
  60                         if (len == 0) len = 1024;
  61                         else len *= 2;
  62                         ret2 = (char *)SMB_REALLOC_KEEP_OLD_ON_ERROR(ret, len);
  63                         if (!ret2) return ret;
  64                         ret = ret2;
  65                 }
  66
  67                 c = fgetc(f);
  68                 (*cl)--;
  69
  70                 if (c == EOF) {
  71                         (*cl) = 0;
  72                         break;
  73                 }
  74
  75                 if (c == '\r') continue;
  76
  77                 if (strchr_m("\n&", c)) break;
  78
  79                 ret[i++] = c;
  80
  81         }
  82
  83
  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
 227 const char *cgi_variable(const char *name)
 228 {
 229         int i;
 230
 231         for (i=0;i<num_variables;i++)
 232                 if (strcmp(variables[i].name, name) == 0)
 233                         return variables[i].value;
 234         return NULL;
 235 }
 236
 237 /***************************************************************************
 238  Version of the above that can't return a NULL pointer.
 239 ***************************************************************************/
 240
 241 const char *cgi_variable_nonull(const char *name)
 242 {
 243         const char *var = cgi_variable(name);
 244         if (var) {
 245                 return var;
 246         } else {
 247                 return "";
 248         }
 249 }
 250
 251 /***************************************************************************
 252 tell a browser about a fatal error in the http processing
 253   ***************************************************************************/
 254 static void cgi_setup_error(const char *err, const char *header, const char *info)
 255 {
 256         if (!got_request) {
 257                 /* damn browsers don't like getting cut off before they give a request */
 258                 char line[1024];
 259                 while (fgets(line, sizeof(line)-1, stdin)) {
 260                         if (strnequal(line,"GET ", 4) ||
 261                             strnequal(line,"POST ", 5) ||
 262                             strnequal(line,"PUT ", 4)) {
 263                                 break;
 264                         }
 265                 }
 266         }
 267
 268         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);
 269         fclose(stdin);
 270         fclose(stdout);
 271         exit(0);
 272 }
 273
 274
 275 /***************************************************************************
 276 tell a browser about a fatal authentication error
 277   ***************************************************************************/
 278 static void cgi_auth_error(void)
 279 {
 280         if (inetd_server) {
 281                 cgi_setup_error("401 Authorization Required",
 282                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 283                                 "You must be authenticated to use this service");
 284         } else {
 285                 printf("Content-Type: text/html\r\n");
 286
 287                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 288                 printf("<BODY><H1>Installation Error</H1>\n");
 289                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 290                 printf("</BODY></HTML>\r\n");
 291         }
 292         exit(0);
 293 }
 294
 295 /***************************************************************************
 296 authenticate when we are running as a CGI
 297   ***************************************************************************/
 298 static void cgi_web_auth(void)
 299 {
 300         const char *user = getenv("REMOTE_USER");
 301         struct passwd *pwd;
 302         const char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 303         const char *tail = "</BODY></HTML>\r\n";
 304
 305         if (!user) {
 306                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 307                        head, tail);
 308                 exit(0);
 309         }
 310
 311         pwd = getpwnam_alloc(NULL, user);
 312         if (!pwd) {
 313                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 314                 exit(0);
 315         }
 316
 317         setuid(0);
 318         setuid(pwd->pw_uid);
 319         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 320                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 321                        head, user, (int)geteuid(), (int)getuid(), tail);
 322                 exit(0);
 323         }
 324         TALLOC_FREE(pwd);
 325 }
 326
 327
 328 /***************************************************************************
 329 handle a http authentication line
 330   ***************************************************************************/
 331 static BOOL cgi_handle_authorization(char *line)
 332 {
 333         char *p;
 334         fstring user, user_pass;
 335         struct passwd *pass = NULL;
 336
 337         if (!strnequal(line,"Basic ", 6)) {
 338                 goto err;
 339         }
 340         line += 6;
 341         while (line[0] == ' ') line++;
 342         base64_decode_inplace(line);
 343         if (!(p=strchr_m(line,':'))) {
 344                 /*
 345                  * Always give the same error so a cracker
 346                  * cannot tell why we fail.
 347                  */
 348                 goto err;
 349         }
 350         *p = 0;
 351
 352         convert_string(CH_UTF8, CH_UNIX,
 353                        line, -1,
 354                        user, sizeof(user), True);
 355
 356         convert_string(CH_UTF8, CH_UNIX,
 357                        p+1, -1,
 358                        user_pass, sizeof(user_pass), True);
 359
 360         /*
 361          * Try and get the user from the UNIX password file.
 362          */
 363
 364         pass = getpwnam_alloc(NULL, user);
 365
 366         /*
 367          * Validate the password they have given.
 368          */
 369
 370         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 371                       strlen(user_pass), NULL, False)) {
 372
 373                 if (pass) {
 374                         /*
 375                          * Password was ok.
 376                          */
 377
 378                         if ( initgroups(pass->pw_name, pass->pw_gid) != 0 )
 379                                 goto err;
 380
 381                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 382
 383                         /* Save the users name */
 384                         C_user = SMB_STRDUP(user);
 385                         TALLOC_FREE(pass);
 386                         return True;
 387                 }
 388         }
 389
 390 err:
 391         cgi_setup_error("401 Bad Authorization",
 392                         "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 393                         "username or password incorrect");
 394
 395         TALLOC_FREE(pass);
 396         return False;
 397 }
 398
 399 /***************************************************************************
 400 is this root?
 401   ***************************************************************************/
 402 BOOL am_root(void)
 403 {
 404         if (geteuid() == 0) {
 405                 return( True);
 406         } else {
 407                 return( False);
 408         }
 409 }
 410
 411 /***************************************************************************
 412 return a ptr to the users name
 413   ***************************************************************************/
 414 char *cgi_user_name(void)
 415 {
 416         return(C_user);
 417 }
 418
 419
 420 /***************************************************************************
 421 handle a file download
 422   ***************************************************************************/
 423 static void cgi_download(char *file)
 424 {
 425         SMB_STRUCT_STAT st;
 426         char buf[1024];
 427         int fd, l, i;
 428         char *p;
 429         char *lang;
 430
 431         /* sanitise the filename */
 432         for (i=0;file[i];i++) {
 433                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 434                         cgi_setup_error("404 File Not Found","",
 435                                         "Illegal character in filename");
 436                 }
 437         }
 438
 439         if (sys_stat(file, &st) != 0)
 440         {
 441                 cgi_setup_error("404 File Not Found","",
 442                                 "The requested file was not found");
 443         }
 444
 445         if (S_ISDIR(st.st_mode))
 446         {
 447                 snprintf(buf, sizeof(buf), "%s/index.html", file);
 448                 if (!file_exist(buf, &st) || !S_ISREG(st.st_mode))
 449                 {
 450                         cgi_setup_error("404 File Not Found","",
 451                                         "The requested file was not found");
 452                 }
 453         }
 454         else if (S_ISREG(st.st_mode))
 455         {
 456                 snprintf(buf, sizeof(buf), "%s", file);
 457         }
 458         else
 459         {
 460                 cgi_setup_error("404 File Not Found","",
 461                                 "The requested file was not found");
 462         }
 463
 464         fd = web_open(buf,O_RDONLY,0);
 465         if (fd == -1) {
 466                 cgi_setup_error("404 File Not Found","",
 467                                 "The requested file was not found");
 468         }
 469         printf("HTTP/1.0 200 OK\r\n");
 470         if ((p=strrchr_m(buf, '.'))) {
 471                 if (strcmp(p,".gif")==0) {
 472                         printf("Content-Type: image/gif\r\n");
 473                 } else if (strcmp(p,".jpg")==0) {
 474                         printf("Content-Type: image/jpeg\r\n");
 475                 } else if (strcmp(p,".png")==0) {
 476                         printf("Content-Type: image/png\r\n");
 477                 } else if (strcmp(p,".css")==0) {
 478                         printf("Content-Type: text/css\r\n");
 479                 } else if (strcmp(p,".txt")==0) {
 480                         printf("Content-Type: text/plain\r\n");
 481                 } else {
 482                         printf("Content-Type: text/html\r\n");
 483                 }
 484         }
 485         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 486
 487         lang = lang_tdb_current();
 488         if (lang) {
 489                 printf("Content-Language: %s\r\n", lang);
 490         }
 491
 492         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 493         while ((l=read(fd,buf,sizeof(buf)))>0) {
 494                 fwrite(buf, 1, l, stdout);
 495         }
 496         close(fd);
 497         exit(0);
 498 }
 499
 500
 501
 502
 503 /**
 504  * @brief Setup the CGI framework.
 505  *
 506  * Setup the cgi framework, handling the possibility that this program
 507  * is either run as a true CGI program with a gateway to a web server, or
 508  * is itself a mini web server.
 509  **/
 510 void cgi_setup(const char *rootdir, int auth_required)
 511 {
 512         BOOL authenticated = False;
 513         char line[1024];
 514         char *url=NULL;
 515         char *p;
 516         char *lang;
 517
 518         if (chdir(rootdir)) {
 519                 cgi_setup_error("500 Server Error", "",
 520                                 "chdir failed - the server is not configured correctly");
 521         }
 522
 523         /* Handle the possibility we might be running as non-root */
 524         sec_init();
 525
 526         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 527                 /* if running as a cgi program */
 528                 web_set_lang(lang);
 529         }
 530
 531         /* maybe we are running under a web server */
 532         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 533                 if (auth_required) {
 534                         cgi_web_auth();
 535                 }
 536                 return;
 537         }
 538
 539         inetd_server = True;
 540
 541         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 542                 cgi_setup_error("403 Forbidden", "",
 543                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 544         }
 545
 546         /* we are a mini-web server. We need to read the request from stdin
 547            and handle authentication etc */
 548         while (fgets(line, sizeof(line)-1, stdin)) {
 549                 if (line[0] == '\r' || line[0] == '\n') break;
 550                 if (strnequal(line,"GET ", 4)) {
 551                         got_request = True;
 552                         url = SMB_STRDUP(&line[4]);
 553                 } else if (strnequal(line,"POST ", 5)) {
 554                         got_request = True;
 555                         request_post = 1;
 556                         url = SMB_STRDUP(&line[5]);
 557                 } else if (strnequal(line,"PUT ", 4)) {
 558                         got_request = True;
 559                         cgi_setup_error("400 Bad Request", "",
 560                                         "This server does not accept PUT requests");
 561                 } else if (strnequal(line,"Authorization: ", 15)) {
 562                         authenticated = cgi_handle_authorization(&line[15]);
 563                 } else if (strnequal(line,"Content-Length: ", 16)) {
 564                         content_length = atoi(&line[16]);
 565                 } else if (strnequal(line,"Accept-Language: ", 17)) {
 566                         web_set_lang(&line[17]);
 567                 }
 568                 /* ignore all other requests! */
 569         }
 570
 571         if (auth_required && !authenticated) {
 572                 cgi_auth_error();
 573         }
 574
 575         if (!url) {
 576                 cgi_setup_error("400 Bad Request", "",
 577                                 "You must specify a GET or POST request");
 578         }
 579
 580         /* trim the URL */
 581         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 582                 *p = 0;
 583         }
 584         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 585                 url[strlen(url)-1] = 0;
 586         }
 587
 588         /* anything following a ? in the URL is part of the query string */
 589         if ((p=strchr_m(url,'?'))) {
 590                 query_string = p+1;
 591                 *p = 0;
 592         }
 593
 594         string_sub(url, "/swat/", "", 0);
 595
 596         if (url[0] != '/' && strstr(url,"..")==0) {
 597                 cgi_download(url);
 598         }
 599
 600         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 601         printf("Date: %s\r\n", http_timestring(time(NULL)));
 602         baseurl = "";
 603         pathinfo = url+1;
 604 }
 605
 606
 607 /***************************************************************************
 608 return the current pages URL
 609   ***************************************************************************/
 610 const char *cgi_baseurl(void)
 611 {
 612         if (inetd_server) {
 613                 return baseurl;
 614         }
 615         return getenv("SCRIPT_NAME");
 616 }
 617
 618 /***************************************************************************
 619 return the current pages path info
 620   ***************************************************************************/
 621 const char *cgi_pathinfo(void)
 622 {
 623         char *r;
 624         if (inetd_server) {
 625                 return pathinfo;
 626         }
 627         r = getenv("PATH_INFO");
 628         if (!r) return "";
 629         if (*r == '/') r++;
 630         return r;
 631 }
 632
 633 /***************************************************************************
 634 return the hostname of the client
 635   ***************************************************************************/
 636 char *cgi_remote_host(void)
 637 {
 638         if (inetd_server) {
 639                 return get_peer_name(1,False);
 640         }
 641         return getenv("REMOTE_HOST");
 642 }
 643
 644 /***************************************************************************
 645 return the hostname of the client
 646   ***************************************************************************/
 647 char *cgi_remote_addr(void)
 648 {
 649         if (inetd_server) {
 650                 return get_peer_addr(1);
 651         }
 652         return getenv("REMOTE_ADDR");
 653 }
 654
 655
 656 /***************************************************************************
 657 return True if the request was a POST
 658   ***************************************************************************/
 659 BOOL cgi_waspost(void)
 660 {
 661         if (inetd_server) {
 662                 return request_post;
 663         }
 664         return strequal(getenv("REQUEST_METHOD"), "POST");
 665 }