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 2 of the License, or
   8    (at your option) any later version.
   9
  10    This program is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program; if not, write to the Free Software
  17    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  18 */
  19
  20
  21 #include "includes.h"
  22 #include "../web/swat_proto.h"
  23
  24 #define MAX_VARIABLES 10000
  25
  26 /* set the expiry on fixed pages */
  27 #define EXPIRY_TIME (60*60*24*7)
  28
  29 #ifdef DEBUG_COMMENTS
  30 extern void print_title(char *fmt, ...);
  31 #endif
  32
  33 struct var {
  34         char *name;
  35         char *value;
  36 };
  37
  38 static struct var variables[MAX_VARIABLES];
  39 static int num_variables;
  40 static int content_length;
  41 static int request_post;
  42 static char *query_string;
  43 static 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 *)Realloc(ret, len);
  63                         if (!ret2) return ret;
  64                         ret = ret2;
  65                 }
  66
  67                 c = fgetc(f);
  68                 (*cl)--;
  69
  70                 if (c == EOF) {
  71                         (*cl) = 0;
  72                         break;
  73                 }
  74
  75                 if (c == '\r') continue;
  76
  77                 if (strchr_m("\n&", c)) break;
  78
  79                 ret[i++] = c;
  80
  81         }
  82
  83
  84         ret[i] = 0;
  85         return ret;
  86 }
  87
  88 /***************************************************************************
  89   load all the variables passed to the CGI program. May have multiple variables
  90   with the same name and the same or different values. Takes a file parameter
  91   for simulating CGI invocation eg loading saved preferences.
  92   ***************************************************************************/
  93 void cgi_load_variables(void)
  94 {
  95         static char *line;
  96         char *p, *s, *tok;
  97         int len, i;
  98         FILE *f = stdin;
  99
 100 #ifdef DEBUG_COMMENTS
 101         char dummy[100]="";
 102         print_title(dummy);
 103         d_printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 104 #endif
 105
 106         if (!content_length) {
 107                 p = getenv("CONTENT_LENGTH");
 108                 len = p?atoi(p):0;
 109         } else {
 110                 len = content_length;
 111         }
 112
 113
 114         if (len > 0 &&
 115             (request_post ||
 116              ((s=getenv("REQUEST_METHOD")) &&
 117               strcasecmp(s,"POST")==0))) {
 118                 while (len && (line=grab_line(f, &len))) {
 119                         p = strchr_m(line,'=');
 120                         if (!p) continue;
 121
 122                         *p = 0;
 123
 124                         variables[num_variables].name = strdup(line);
 125                         variables[num_variables].value = strdup(p+1);
 126
 127                         SAFE_FREE(line);
 128
 129                         if (!variables[num_variables].name ||
 130                             !variables[num_variables].value)
 131                                 continue;
 132
 133                         rfc1738_unescape(variables[num_variables].value);
 134                         rfc1738_unescape(variables[num_variables].name);
 135
 136 #ifdef DEBUG_COMMENTS
 137                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 138                                variables[num_variables].name,
 139                                variables[num_variables].value);
 140 #endif
 141
 142                         num_variables++;
 143                         if (num_variables == MAX_VARIABLES) break;
 144                 }
 145         }
 146
 147         fclose(stdin);
 148         open("/dev/null", O_RDWR);
 149
 150         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 151                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 152                         p = strchr_m(tok,'=');
 153                         if (!p) continue;
 154
 155                         *p = 0;
 156
 157                         variables[num_variables].name = strdup(tok);
 158                         variables[num_variables].value = strdup(p+1);
 159
 160                         if (!variables[num_variables].name ||
 161                             !variables[num_variables].value)
 162                                 continue;
 163
 164                         rfc1738_unescape(variables[num_variables].value);
 165                         rfc1738_unescape(variables[num_variables].name);
 166
 167 #ifdef DEBUG_COMMENTS
 168                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 169                                variables[num_variables].name,
 170                                variables[num_variables].value);
 171 #endif
 172                         num_variables++;
 173                         if (num_variables == MAX_VARIABLES) break;
 174                 }
 175
 176         }
 177 #ifdef DEBUG_COMMENTS
 178         printf("<!== End dump in cgi_load_variables() ==>\n");
 179 #endif
 180
 181         /* variables from the client are in display charset - convert them
 182            to our internal charset before use */
 183         for (i=0;i<num_variables;i++) {
 184                 pstring dest;
 185
 186                 convert_string(CH_DISPLAY, CH_UNIX,
 187                                variables[i].name, -1,
 188                                dest, sizeof(dest));
 189                 free(variables[i].name);
 190                 variables[i].name = strdup(dest);
 191
 192                 convert_string(CH_DISPLAY, CH_UNIX,
 193                                variables[i].value, -1,
 194                                dest, sizeof(dest));
 195                 free(variables[i].value);
 196                 variables[i].value = strdup(dest);
 197         }
 198 }
 199
 200
 201 /***************************************************************************
 202   find a variable passed via CGI
 203   Doesn't quite do what you think in the case of POST text variables, because
 204   if they exist they might have a value of "" or even " ", depending on the
 205   browser. Also doesn't allow for variables[] containing multiple variables
 206   with the same name and the same or different values.
 207   ***************************************************************************/
 208 char *cgi_variable(char *name)
 209 {
 210         int i;
 211
 212         for (i=0;i<num_variables;i++)
 213                 if (strcmp(variables[i].name, name) == 0)
 214                         return variables[i].value;
 215         return NULL;
 216 }
 217
 218 /***************************************************************************
 219 tell a browser about a fatal error in the http processing
 220   ***************************************************************************/
 221 static void cgi_setup_error(char *err, char *header, char *info)
 222 {
 223         if (!got_request) {
 224                 /* damn browsers don't like getting cut off before they give a request */
 225                 char line[1024];
 226                 while (fgets(line, sizeof(line)-1, stdin)) {
 227                         if (strncasecmp(line,"GET ", 4)==0 ||
 228                             strncasecmp(line,"POST ", 5)==0 ||
 229                             strncasecmp(line,"PUT ", 4)==0) {
 230                                 break;
 231                         }
 232                 }
 233         }
 234
 235         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);
 236         fclose(stdin);
 237         fclose(stdout);
 238         exit(0);
 239 }
 240
 241
 242 /***************************************************************************
 243 tell a browser about a fatal authentication error
 244   ***************************************************************************/
 245 static void cgi_auth_error(void)
 246 {
 247         if (inetd_server) {
 248                 cgi_setup_error("401 Authorization Required",
 249                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 250                                 "You must be authenticated to use this service");
 251         } else {
 252                 printf("Content-Type: text/html\r\n");
 253
 254                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 255                 printf("<BODY><H1>Installation Error</H1>\n");
 256                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 257                 printf("</BODY></HTML>\r\n");
 258         }
 259         exit(0);
 260 }
 261
 262 /***************************************************************************
 263 authenticate when we are running as a CGI
 264   ***************************************************************************/
 265 static void cgi_web_auth(void)
 266 {
 267         char *user = getenv("REMOTE_USER");
 268         struct passwd *pwd;
 269         char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 270         char *tail = "</BODY></HTML>\r\n";
 271
 272         if (!user) {
 273                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 274                        head, tail);
 275                 exit(0);
 276         }
 277
 278         pwd = getpwnam_alloc(user);
 279         if (!pwd) {
 280                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 281                 exit(0);
 282         }
 283
 284         setuid(0);
 285         setuid(pwd->pw_uid);
 286         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 287                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 288                        head, user, (int)geteuid(), (int)getuid(), tail);
 289                 exit(0);
 290         }
 291         passwd_free(&pwd);
 292 }
 293
 294 /***************************************************************************
 295 decode a base64 string in-place - simple and slow algorithm
 296   ***************************************************************************/
 297 static void base64_decode(char *s)
 298 {
 299         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 300         int bit_offset, byte_offset, idx, i, n;
 301         unsigned char *d = (unsigned char *)s;
 302         char *p;
 303
 304         n=i=0;
 305
 306         while (*s && (p=strchr_m(b64,*s))) {
 307                 idx = (int)(p - b64);
 308                 byte_offset = (i*6)/8;
 309                 bit_offset = (i*6)%8;
 310                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 311                 if (bit_offset < 3) {
 312                         d[byte_offset] |= (idx << (2-bit_offset));
 313                         n = byte_offset+1;
 314                 } else {
 315                         d[byte_offset] |= (idx >> (bit_offset-2));
 316                         d[byte_offset+1] = 0;
 317                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 318                         n = byte_offset+2;
 319                 }
 320                 s++; i++;
 321         }
 322         /* null terminate */
 323         d[n] = 0;
 324 }
 325
 326 /***************************************************************************
 327 handle a http authentication line
 328   ***************************************************************************/
 329 static BOOL cgi_handle_authorization(char *line)
 330 {
 331         char *p, *user, *user_pass;
 332         struct passwd *pass = NULL;
 333
 334         if (strncasecmp(line,"Basic ", 6)) {
 335                 goto err;
 336         }
 337         line += 6;
 338         while (line[0] == ' ') line++;
 339         base64_decode(line);
 340         if (!(p=strchr_m(line,':'))) {
 341                 /*
 342                  * Always give the same error so a cracker
 343                  * cannot tell why we fail.
 344                  */
 345                 goto err;
 346         }
 347         *p = 0;
 348         user = line;
 349         user_pass = p+1;
 350
 351         /*
 352          * Try and get the user from the UNIX password file.
 353          */
 354
 355         pass = getpwnam_alloc(user);
 356
 357         /*
 358          * Validate the password they have given.
 359          */
 360
 361         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 362                       strlen(user_pass), NULL, False)) {
 363
 364                 if (pass) {
 365                         /*
 366                          * Password was ok.
 367                          */
 368
 369                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 370
 371                         /* Save the users name */
 372                         C_user = strdup(user);
 373                         passwd_free(&pass);
 374                         return True;
 375                 }
 376         }
 377
 378 err:
 379         cgi_setup_error("401 Bad Authorization", "",
 380                         "username or password incorrect");
 381
 382         passwd_free(&pass);
 383         return False;
 384 }
 385
 386 /***************************************************************************
 387 is this root?
 388   ***************************************************************************/
 389 BOOL am_root(void)
 390 {
 391         if (geteuid() == 0) {
 392                 return( True);
 393         } else {
 394                 return( False);
 395         }
 396 }
 397
 398 /***************************************************************************
 399 return a ptr to the users name
 400   ***************************************************************************/
 401 char *cgi_user_name(void)
 402 {
 403         return(C_user);
 404 }
 405
 406
 407 /***************************************************************************
 408 handle a file download
 409   ***************************************************************************/
 410 static void cgi_download(char *file)
 411 {
 412         SMB_STRUCT_STAT st;
 413         char buf[1024];
 414         int fd, l, i;
 415         char *p;
 416         char *lang;
 417
 418         /* sanitise the filename */
 419         for (i=0;file[i];i++) {
 420                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 421                         cgi_setup_error("404 File Not Found","",
 422                                         "Illegal character in filename");
 423                 }
 424         }
 425
 426         if (!file_exist(file, &st)) {
 427                 cgi_setup_error("404 File Not Found","",
 428                                 "The requested file was not found");
 429         }
 430
 431         fd = web_open(file,O_RDONLY,0);
 432         if (fd == -1) {
 433                 cgi_setup_error("404 File Not Found","",
 434                                 "The requested file was not found");
 435         }
 436         printf("HTTP/1.0 200 OK\r\n");
 437         if ((p=strrchr_m(file,'.'))) {
 438                 if (strcmp(p,".gif")==0) {
 439                         printf("Content-Type: image/gif\r\n");
 440                 } else if (strcmp(p,".jpg")==0) {
 441                         printf("Content-Type: image/jpeg\r\n");
 442                 } else if (strcmp(p,".txt")==0) {
 443                         printf("Content-Type: text/plain\r\n");
 444                 } else {
 445                         printf("Content-Type: text/html\r\n");
 446                 }
 447         }
 448         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 449
 450         lang = lang_tdb_current();
 451         if (lang) {
 452                 printf("Content-Language: %s\r\n", lang);
 453         }
 454
 455         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 456         while ((l=read(fd,buf,sizeof(buf)))>0) {
 457                 fwrite(buf, 1, l, stdout);
 458         }
 459         close(fd);
 460         exit(0);
 461 }
 462
 463
 464
 465
 466 /**
 467  * @brief Setup the CGI framework.
 468  *
 469  * Setup the cgi framework, handling the possibility that this program
 470  * is either run as a true CGI program with a gateway to a web server, or
 471  * is itself a mini web server.
 472  **/
 473 void cgi_setup(const char *rootdir, int auth_required)
 474 {
 475         BOOL authenticated = False;
 476         char line[1024];
 477         char *url=NULL;
 478         char *p;
 479         char *lang;
 480
 481         if (chdir(rootdir)) {
 482                 cgi_setup_error("400 Server Error", "",
 483                                 "chdir failed - the server is not configured correctly");
 484         }
 485
 486         /* Handle the possability we might be running as non-root */
 487         sec_init();
 488
 489         if ((lang=getenv("HTTP_ACCEPT_LANGUAGE"))) {
 490                 /* if running as a cgi program */
 491                 web_set_lang(lang);
 492         }
 493
 494         /* maybe we are running under a web server */
 495         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 496                 if (auth_required) {
 497                         cgi_web_auth();
 498                 }
 499                 return;
 500         }
 501
 502         inetd_server = True;
 503
 504         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 505                 cgi_setup_error("400 Server Error", "",
 506                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 507         }
 508
 509         /* we are a mini-web server. We need to read the request from stdin
 510            and handle authentication etc */
 511         while (fgets(line, sizeof(line)-1, stdin)) {
 512                 if (line[0] == '\r' || line[0] == '\n') break;
 513                 if (strncasecmp(line,"GET ", 4)==0) {
 514                         got_request = True;
 515                         url = strdup(&line[4]);
 516                 } else if (strncasecmp(line,"POST ", 5)==0) {
 517                         got_request = True;
 518                         request_post = 1;
 519                         url = strdup(&line[5]);
 520                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 521                         got_request = True;
 522                         cgi_setup_error("400 Bad Request", "",
 523                                         "This server does not accept PUT requests");
 524                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 525                         authenticated = cgi_handle_authorization(&line[15]);
 526                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 527                         content_length = atoi(&line[16]);
 528                 } else if (strncasecmp(line,"Accept-Language: ", 17)==0) {
 529                         web_set_lang(&line[17]);
 530                 }
 531                 /* ignore all other requests! */
 532         }
 533
 534         if (auth_required && !authenticated) {
 535                 cgi_auth_error();
 536         }
 537
 538         if (!url) {
 539                 cgi_setup_error("400 Bad Request", "",
 540                                 "You must specify a GET or POST request");
 541         }
 542
 543         /* trim the URL */
 544         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 545                 *p = 0;
 546         }
 547         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 548                 url[strlen(url)-1] = 0;
 549         }
 550
 551         /* anything following a ? in the URL is part of the query string */
 552         if ((p=strchr_m(url,'?'))) {
 553                 query_string = p+1;
 554                 *p = 0;
 555         }
 556
 557         string_sub(url, "/swat/", "", 0);
 558
 559         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 560                 cgi_download(url);
 561         }
 562
 563         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 564         printf("Date: %s\r\n", http_timestring(time(NULL)));
 565         baseurl = "";
 566         pathinfo = url+1;
 567 }
 568
 569
 570 /***************************************************************************
 571 return the current pages URL
 572   ***************************************************************************/
 573 char *cgi_baseurl(void)
 574 {
 575         if (inetd_server) {
 576                 return baseurl;
 577         }
 578         return getenv("SCRIPT_NAME");
 579 }
 580
 581 /***************************************************************************
 582 return the current pages path info
 583   ***************************************************************************/
 584 char *cgi_pathinfo(void)
 585 {
 586         char *r;
 587         if (inetd_server) {
 588                 return pathinfo;
 589         }
 590         r = getenv("PATH_INFO");
 591         if (!r) return "";
 592         if (*r == '/') r++;
 593         return r;
 594 }
 595
 596 /***************************************************************************
 597 return the hostname of the client
 598   ***************************************************************************/
 599 char *cgi_remote_host(void)
 600 {
 601         if (inetd_server) {
 602                 return get_socket_name(1,False);
 603         }
 604         return getenv("REMOTE_HOST");
 605 }
 606
 607 /***************************************************************************
 608 return the hostname of the client
 609   ***************************************************************************/
 610 char *cgi_remote_addr(void)
 611 {
 612         if (inetd_server) {
 613                 return get_socket_addr(1);
 614         }
 615         return getenv("REMOTE_ADDR");
 616 }
 617
 618
 619 /***************************************************************************
 620 return True if the request was a POST
 621   ***************************************************************************/
 622 BOOL cgi_waspost(void)
 623 {
 624         if (inetd_server) {
 625                 return request_post;
 626         }
 627         return strequal(getenv("REQUEST_METHOD"), "POST");
 628 }