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 "smb.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 void unescape(char *buf)
  50 {
  51         char *p=buf;
  52
  53         while ((p=strchr_m(p,'+')))
  54                 *p = ' ';
  55
  56         p = buf;
  57
  58         while (p && *p && (p=strchr_m(p,'%'))) {
  59                 int c1 = p[1];
  60                 int c2 = p[2];
  61
  62                 if (c1 >= '0' && c1 <= '9')
  63                         c1 = c1 - '0';
  64                 else if (c1 >= 'A' && c1 <= 'F')
  65                         c1 = 10 + c1 - 'A';
  66                 else if (c1 >= 'a' && c1 <= 'f')
  67                         c1 = 10 + c1 - 'a';
  68                 else {p++; continue;}
  69
  70                 if (c2 >= '0' && c2 <= '9')
  71                         c2 = c2 - '0';
  72                 else if (c2 >= 'A' && c2 <= 'F')
  73                         c2 = 10 + c2 - 'A';
  74                 else if (c2 >= 'a' && c2 <= 'f')
  75                         c2 = 10 + c2 - 'a';
  76                 else {p++; continue;}
  77
  78                 *p = (c1<<4) | c2;
  79
  80                 memcpy(p+1, p+3, strlen(p+3)+1);
  81                 p++;
  82         }
  83 }
  84
  85
  86 static char *grab_line(FILE *f, int *cl)
  87 {
  88         char *ret = NULL;
  89         int i = 0;
  90         int len = 0;
  91
  92         while ((*cl)) {
  93                 int c;
  94
  95                 if (i == len) {
  96                         char *ret2;
  97                         if (len == 0) len = 1024;
  98                         else len *= 2;
  99                         ret2 = (char *)Realloc(ret, len);
 100                         if (!ret2) return ret;
 101                         ret = ret2;
 102                 }
 103
 104                 c = fgetc(f);
 105                 (*cl)--;
 106
 107                 if (c == EOF) {
 108                         (*cl) = 0;
 109                         break;
 110                 }
 111
 112                 if (c == '\r') continue;
 113
 114                 if (strchr_m("\n&", c)) break;
 115
 116                 ret[i++] = c;
 117
 118         }
 119
 120
 121         ret[i] = 0;
 122         return ret;
 123 }
 124
 125 /***************************************************************************
 126   load all the variables passed to the CGI program. May have multiple variables
 127   with the same name and the same or different values. Takes a file parameter
 128   for simulating CGI invocation eg loading saved preferences.
 129   ***************************************************************************/
 130 void cgi_load_variables(void)
 131 {
 132         static char *line;
 133         char *p, *s, *tok;
 134         int len, i;
 135         FILE *f = stdin;
 136
 137 #ifdef DEBUG_COMMENTS
 138         char dummy[100]="";
 139         print_title(dummy);
 140         printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 141 #endif
 142
 143         if (!content_length) {
 144                 p = getenv("CONTENT_LENGTH");
 145                 len = p?atoi(p):0;
 146         } else {
 147                 len = content_length;
 148         }
 149
 150
 151         if (len > 0 &&
 152             (request_post ||
 153              ((s=getenv("REQUEST_METHOD")) &&
 154               strcasecmp(s,"POST")==0))) {
 155                 while (len && (line=grab_line(f, &len))) {
 156                         p = strchr_m(line,'=');
 157                         if (!p) continue;
 158
 159                         *p = 0;
 160
 161                         variables[num_variables].name = strdup(line);
 162                         variables[num_variables].value = strdup(p+1);
 163
 164                         SAFE_FREE(line);
 165
 166                         if (!variables[num_variables].name ||
 167                             !variables[num_variables].value)
 168                                 continue;
 169
 170                         unescape(variables[num_variables].value);
 171                         unescape(variables[num_variables].name);
 172
 173 #ifdef DEBUG_COMMENTS
 174                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 175                                variables[num_variables].name,
 176                                variables[num_variables].value);
 177 #endif
 178
 179                         num_variables++;
 180                         if (num_variables == MAX_VARIABLES) break;
 181                 }
 182         }
 183
 184         fclose(stdin);
 185         open("/dev/null", O_RDWR);
 186
 187         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 188                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 189                         p = strchr_m(tok,'=');
 190                         if (!p) continue;
 191
 192                         *p = 0;
 193
 194                         variables[num_variables].name = strdup(tok);
 195                         variables[num_variables].value = strdup(p+1);
 196
 197                         if (!variables[num_variables].name ||
 198                             !variables[num_variables].value)
 199                                 continue;
 200
 201                         unescape(variables[num_variables].value);
 202                         unescape(variables[num_variables].name);
 203
 204 #ifdef DEBUG_COMMENTS
 205                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 206                                variables[num_variables].name,
 207                                variables[num_variables].value);
 208 #endif
 209                         num_variables++;
 210                         if (num_variables == MAX_VARIABLES) break;
 211                 }
 212
 213         }
 214 #ifdef DEBUG_COMMENTS
 215         printf("<!== End dump in cgi_load_variables() ==>\n");
 216 #endif
 217
 218         /* variables from the client are in display charset - convert them
 219            to our internal charset before use */
 220         for (i=0;i<num_variables;i++) {
 221                 pstring dest;
 222
 223                 convert_string(CH_DISPLAY, CH_UNIX,
 224                                variables[i].name, strlen(variables[i].name),
 225                                dest, sizeof(dest));
 226                 free(variables[i].name);
 227                 variables[i].name = strdup(dest);
 228
 229                 convert_string(CH_DISPLAY, CH_UNIX,
 230                                variables[i].value, strlen(variables[i].name),
 231                                dest, sizeof(dest));
 232                 free(variables[i].value);
 233                 variables[i].value = strdup(dest);
 234         }
 235 }
 236
 237
 238 /***************************************************************************
 239   find a variable passed via CGI
 240   Doesn't quite do what you think in the case of POST text variables, because
 241   if they exist they might have a value of "" or even " ", depending on the
 242   browser. Also doesn't allow for variables[] containing multiple variables
 243   with the same name and the same or different values.
 244   ***************************************************************************/
 245 char *cgi_variable(char *name)
 246 {
 247         int i;
 248
 249         for (i=0;i<num_variables;i++)
 250                 if (strcmp(variables[i].name, name) == 0)
 251                         return variables[i].value;
 252         return NULL;
 253 }
 254
 255 /***************************************************************************
 256 tell a browser about a fatal error in the http processing
 257   ***************************************************************************/
 258 static void cgi_setup_error(char *err, char *header, char *info)
 259 {
 260         if (!got_request) {
 261                 /* damn browsers don't like getting cut off before they give a request */
 262                 char line[1024];
 263                 while (fgets(line, sizeof(line)-1, stdin)) {
 264                         if (strncasecmp(line,"GET ", 4)==0 ||
 265                             strncasecmp(line,"POST ", 5)==0 ||
 266                             strncasecmp(line,"PUT ", 4)==0) {
 267                                 break;
 268                         }
 269                 }
 270         }
 271
 272         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);
 273         fclose(stdin);
 274         fclose(stdout);
 275         exit(0);
 276 }
 277
 278
 279 /***************************************************************************
 280 tell a browser about a fatal authentication error
 281   ***************************************************************************/
 282 static void cgi_auth_error(void)
 283 {
 284         if (inetd_server) {
 285                 cgi_setup_error("401 Authorization Required",
 286                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 287                                 "You must be authenticated to use this service");
 288         } else {
 289                 printf("Content-Type: text/html\r\n");
 290
 291                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 292                 printf("<BODY><H1>Installation Error</H1>\n");
 293                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 294                 printf("</BODY></HTML>\r\n");
 295         }
 296         exit(0);
 297 }
 298
 299 /***************************************************************************
 300 authenticate when we are running as a CGI
 301   ***************************************************************************/
 302 static void cgi_web_auth(void)
 303 {
 304         char *user = getenv("REMOTE_USER");
 305         struct passwd *pwd;
 306         char *head = "Content-Type: text/html\r\n\r\n<HTML><BODY><H1>SWAT installation Error</H1>\n";
 307         char *tail = "</BODY></HTML>\r\n";
 308
 309         if (!user) {
 310                 printf("%sREMOTE_USER not set. Not authenticated by web server.<br>%s\n",
 311                        head, tail);
 312                 exit(0);
 313         }
 314
 315         pwd = getpwnam(user);
 316         if (!pwd) {
 317                 printf("%sCannot find user %s<br>%s\n", head, user, tail);
 318                 exit(0);
 319         }
 320
 321         setuid(0);
 322         setuid(pwd->pw_uid);
 323         if (geteuid() != pwd->pw_uid || getuid() != pwd->pw_uid) {
 324                 printf("%sFailed to become user %s - uid=%d/%d<br>%s\n",
 325                        head, user, (int)geteuid(), (int)getuid(), tail);
 326                 exit(0);
 327         }
 328 }
 329
 330 /***************************************************************************
 331 decode a base64 string in-place - simple and slow algorithm
 332   ***************************************************************************/
 333 static void base64_decode(char *s)
 334 {
 335         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 336         int bit_offset, byte_offset, idx, i, n;
 337         unsigned char *d = (unsigned char *)s;
 338         char *p;
 339
 340         n=i=0;
 341
 342         while (*s && (p=strchr_m(b64,*s))) {
 343                 idx = (int)(p - b64);
 344                 byte_offset = (i*6)/8;
 345                 bit_offset = (i*6)%8;
 346                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 347                 if (bit_offset < 3) {
 348                         d[byte_offset] |= (idx << (2-bit_offset));
 349                         n = byte_offset+1;
 350                 } else {
 351                         d[byte_offset] |= (idx >> (bit_offset-2));
 352                         d[byte_offset+1] = 0;
 353                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 354                         n = byte_offset+2;
 355                 }
 356                 s++; i++;
 357         }
 358         /* null terminate */
 359         d[n] = 0;
 360 }
 361
 362 /***************************************************************************
 363 handle a http authentication line
 364   ***************************************************************************/
 365 static BOOL cgi_handle_authorization(char *line)
 366 {
 367         char *p, *user, *user_pass;
 368         struct passwd *pass = NULL;
 369
 370         if (strncasecmp(line,"Basic ", 6)) {
 371                 goto err;
 372         }
 373         line += 6;
 374         while (line[0] == ' ') line++;
 375         base64_decode(line);
 376         if (!(p=strchr_m(line,':'))) {
 377                 /*
 378                  * Always give the same error so a cracker
 379                  * cannot tell why we fail.
 380                  */
 381                 goto err;
 382         }
 383         *p = 0;
 384         user = line;
 385         user_pass = p+1;
 386
 387         /*
 388          * Try and get the user from the UNIX password file.
 389          */
 390
 391         pass = sys_getpwnam(user);
 392
 393         /*
 394          * Validate the password they have given.
 395          */
 396
 397         if NT_STATUS_IS_OK(pass_check(pass, user, user_pass,
 398                       strlen(user_pass), NULL, False)) {
 399
 400                 if (pass) {
 401                         /*
 402                          * Password was ok.
 403                          */
 404
 405                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 406
 407                         /* Save the users name */
 408                         C_user = strdup(user);
 409                         return True;
 410                 }
 411         }
 412
 413 err:
 414         cgi_setup_error("401 Bad Authorization", "",
 415                         "username or password incorrect");
 416
 417         return False;
 418 }
 419
 420 /***************************************************************************
 421 is this root?
 422   ***************************************************************************/
 423 BOOL am_root(void)
 424 {
 425         if (geteuid() == 0) {
 426                 return( True);
 427         } else {
 428                 return( False);
 429         }
 430 }
 431
 432 /***************************************************************************
 433 return a ptr to the users name
 434   ***************************************************************************/
 435 char *cgi_user_name(void)
 436 {
 437         return(C_user);
 438 }
 439
 440
 441 /***************************************************************************
 442 handle a file download
 443   ***************************************************************************/
 444 static void cgi_download(char *file)
 445 {
 446         SMB_STRUCT_STAT st;
 447         char buf[1024];
 448         int fd, l, i;
 449         char *p;
 450
 451         /* sanitise the filename */
 452         for (i=0;file[i];i++) {
 453                 if (!isalnum((int)file[i]) && !strchr_m("/.-_", file[i])) {
 454                         cgi_setup_error("404 File Not Found","",
 455                                         "Illegal character in filename");
 456                 }
 457         }
 458
 459         if (!file_exist(file, &st)) {
 460                 cgi_setup_error("404 File Not Found","",
 461                                 "The requested file was not found");
 462         }
 463         fd = sys_open(file,O_RDONLY,0);
 464         if (fd == -1) {
 465                 cgi_setup_error("404 File Not Found","",
 466                                 "The requested file was not found");
 467         }
 468         printf("HTTP/1.0 200 OK\r\n");
 469         if ((p=strrchr_m(file,'.'))) {
 470                 if (strcmp(p,".gif")==0) {
 471                         printf("Content-Type: image/gif\r\n");
 472                 } else if (strcmp(p,".jpg")==0) {
 473                         printf("Content-Type: image/jpeg\r\n");
 474                 } else if (strcmp(p,".txt")==0) {
 475                         printf("Content-Type: text/plain\r\n");
 476                 } else {
 477                         printf("Content-Type: text/html\r\n");
 478                 }
 479         }
 480         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 481
 482         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 483         while ((l=read(fd,buf,sizeof(buf)))>0) {
 484                 fwrite(buf, 1, l, stdout);
 485         }
 486         close(fd);
 487         exit(0);
 488 }
 489
 490
 491
 492
 493 /***************************************************************************
 494 setup the cgi framework, handling the possability that this program is either
 495 run as a true cgi program by a web browser or is itself a mini web server
 496   ***************************************************************************/
 497 void cgi_setup(char *rootdir, int auth_required)
 498 {
 499         BOOL authenticated = False;
 500         char line[1024];
 501         char *url=NULL;
 502         char *p;
 503
 504         if (chdir(rootdir)) {
 505                 cgi_setup_error("400 Server Error", "",
 506                                 "chdir failed - the server is not configured correctly");
 507         }
 508
 509         /* Handle the possability we might be running as non-root */
 510         sec_init();
 511
 512         /* maybe we are running under a web server */
 513         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 514                 if (auth_required) {
 515                         cgi_web_auth();
 516                 }
 517                 return;
 518         }
 519
 520         inetd_server = True;
 521
 522         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 523                 cgi_setup_error("400 Server Error", "",
 524                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 525         }
 526
 527         /* we are a mini-web server. We need to read the request from stdin
 528            and handle authentication etc */
 529         while (fgets(line, sizeof(line)-1, stdin)) {
 530                 if (line[0] == '\r' || line[0] == '\n') break;
 531                 if (strncasecmp(line,"GET ", 4)==0) {
 532                         got_request = True;
 533                         url = strdup(&line[4]);
 534                 } else if (strncasecmp(line,"POST ", 5)==0) {
 535                         got_request = True;
 536                         request_post = 1;
 537                         url = strdup(&line[5]);
 538                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 539                         got_request = True;
 540                         cgi_setup_error("400 Bad Request", "",
 541                                         "This server does not accept PUT requests");
 542                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 543                         authenticated = cgi_handle_authorization(&line[15]);
 544                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 545                         content_length = atoi(&line[16]);
 546                 }
 547                 /* ignore all other requests! */
 548         }
 549
 550         if (auth_required && !authenticated) {
 551                 cgi_auth_error();
 552         }
 553
 554         if (!url) {
 555                 cgi_setup_error("400 Bad Request", "",
 556                                 "You must specify a GET or POST request");
 557         }
 558
 559         /* trim the URL */
 560         if ((p = strchr_m(url,' ')) || (p=strchr_m(url,'\t'))) {
 561                 *p = 0;
 562         }
 563         while (*url && strchr_m("\r\n",url[strlen(url)-1])) {
 564                 url[strlen(url)-1] = 0;
 565         }
 566
 567         /* anything following a ? in the URL is part of the query string */
 568         if ((p=strchr_m(url,'?'))) {
 569                 query_string = p+1;
 570                 *p = 0;
 571         }
 572
 573         string_sub(url, "/swat/", "", 0);
 574
 575         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 576                 cgi_download(url);
 577         }
 578
 579         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 580         printf("Date: %s\r\n", http_timestring(time(NULL)));
 581         baseurl = "";
 582         pathinfo = url+1;
 583 }
 584
 585
 586 /***************************************************************************
 587 return the current pages URL
 588   ***************************************************************************/
 589 char *cgi_baseurl(void)
 590 {
 591         if (inetd_server) {
 592                 return baseurl;
 593         }
 594         return getenv("SCRIPT_NAME");
 595 }
 596
 597 /***************************************************************************
 598 return the current pages path info
 599   ***************************************************************************/
 600 char *cgi_pathinfo(void)
 601 {
 602         char *r;
 603         if (inetd_server) {
 604                 return pathinfo;
 605         }
 606         r = getenv("PATH_INFO");
 607         if (!r) return "";
 608         if (*r == '/') r++;
 609         return r;
 610 }
 611
 612 /***************************************************************************
 613 return the hostname of the client
 614   ***************************************************************************/
 615 char *cgi_remote_host(void)
 616 {
 617         if (inetd_server) {
 618                 return get_socket_name(1);
 619         }
 620         return getenv("REMOTE_HOST");
 621 }
 622
 623 /***************************************************************************
 624 return the hostname of the client
 625   ***************************************************************************/
 626 char *cgi_remote_addr(void)
 627 {
 628         if (inetd_server) {
 629                 return get_socket_addr(1);
 630         }
 631         return getenv("REMOTE_ADDR");
 632 }
 633
 634
 635 /***************************************************************************
 636 return True if the request was a POST
 637   ***************************************************************************/
 638 BOOL cgi_waspost(void)
 639 {
 640         if (inetd_server) {
 641                 return request_post;
 642         }
 643         return strequal(getenv("REQUEST_METHOD"), "POST");
 644 }