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 #define CGI_LOGGING 0
  30
  31 #ifdef DEBUG_COMMENTS
  32 extern void print_title(char *fmt, ...);
  33 #endif
  34
  35 struct var {
  36         char *name;
  37         char *value;
  38 };
  39
  40 static struct var variables[MAX_VARIABLES];
  41 static int num_variables;
  42 static int content_length;
  43 static int request_post;
  44 static char *query_string;
  45 static char *baseurl;
  46 static char *pathinfo;
  47 static char *C_user;
  48 static BOOL inetd_server;
  49 static BOOL got_request;
  50
  51 static void unescape(char *buf)
  52 {
  53         char *p=buf;
  54
  55         while ((p=strchr(p,'+')))
  56                 *p = ' ';
  57
  58         p = buf;
  59
  60         while (p && *p && (p=strchr(p,'%'))) {
  61                 int c1 = p[1];
  62                 int c2 = p[2];
  63
  64                 if (c1 >= '0' && c1 <= '9')
  65                         c1 = c1 - '0';
  66                 else if (c1 >= 'A' && c1 <= 'F')
  67                         c1 = 10 + c1 - 'A';
  68                 else if (c1 >= 'a' && c1 <= 'f')
  69                         c1 = 10 + c1 - 'a';
  70                 else {p++; continue;}
  71
  72                 if (c2 >= '0' && c2 <= '9')
  73                         c2 = c2 - '0';
  74                 else if (c2 >= 'A' && c2 <= 'F')
  75                         c2 = 10 + c2 - 'A';
  76                 else if (c2 >= 'a' && c2 <= 'f')
  77                         c2 = 10 + c2 - 'a';
  78                 else {p++; continue;}
  79
  80                 *p = (c1<<4) | c2;
  81
  82                 memcpy(p+1, p+3, strlen(p+3)+1);
  83                 p++;
  84         }
  85 }
  86
  87
  88 static char *grab_line(FILE *f, int *cl)
  89 {
  90         char *ret;
  91         int i = 0;
  92         int len = 1024;
  93
  94         ret = (char *)malloc(len);
  95         if (!ret) return NULL;
  96
  97
  98         while ((*cl)) {
  99                 int c = fgetc(f);
 100                 (*cl)--;
 101
 102                 if (c == EOF) {
 103                         (*cl) = 0;
 104                         break;
 105                 }
 106
 107                 if (c == '\r') continue;
 108
 109                 if (strchr("\n&", c)) break;
 110
 111                 ret[i++] = c;
 112
 113                 if (i == len-1) {
 114                         char *ret2;
 115                         ret2 = (char *)realloc(ret, len*2);
 116                         if (!ret2) return ret;
 117                         len *= 2;
 118                         ret = ret2;
 119                 }
 120         }
 121
 122
 123         ret[i] = 0;
 124         return ret;
 125 }
 126
 127 /***************************************************************************
 128   load all the variables passed to the CGI program. May have multiple variables
 129   with the same name and the same or different values. Takes a file parameter
 130   for simulating CGI invocation eg loading saved preferences.
 131   ***************************************************************************/
 132 void cgi_load_variables(FILE *f1)
 133 {
 134         FILE *f = f1;
 135         static char *line;
 136         char *p, *s, *tok;
 137         int len;
 138
 139 #ifdef DEBUG_COMMENTS
 140         char dummy[100]="";
 141         print_title(dummy);
 142         printf("<!== Start dump in cgi_load_variables() %s ==>\n",__FILE__);
 143 #endif
 144
 145         if (!f1) {
 146                 f = stdin;
 147                 if (!content_length) {
 148                         p = getenv("CONTENT_LENGTH");
 149                         len = p?atoi(p):0;
 150                 } else {
 151                         len = content_length;
 152                 }
 153         } else {
 154                 fseek(f, 0, SEEK_END);
 155                 len = ftell(f);
 156                 fseek(f, 0, SEEK_SET);
 157         }
 158
 159
 160         if (len > 0 &&
 161             (f1 || request_post ||
 162              ((s=getenv("REQUEST_METHOD")) &&
 163               strcasecmp(s,"POST")==0))) {
 164                 while (len && (line=grab_line(f, &len))) {
 165                         p = strchr(line,'=');
 166                         if (!p) continue;
 167
 168                         *p = 0;
 169
 170                         variables[num_variables].name = strdup(line);
 171                         variables[num_variables].value = strdup(p+1);
 172
 173                         free(line);
 174
 175                         if (!variables[num_variables].name ||
 176                             !variables[num_variables].value)
 177                                 continue;
 178
 179                         unescape(variables[num_variables].value);
 180                         unescape(variables[num_variables].name);
 181
 182 #ifdef DEBUG_COMMENTS
 183                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 184                                variables[num_variables].name,
 185                                variables[num_variables].value);
 186 #endif
 187
 188                         num_variables++;
 189                         if (num_variables == MAX_VARIABLES) break;
 190                 }
 191         }
 192
 193         if (f1) {
 194 #ifdef DEBUG_COMMENTS
 195                 printf("<!== End dump in cgi_load_variables() ==>\n");
 196 #endif
 197                 return;
 198         }
 199
 200         fclose(stdin);
 201
 202         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 203                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 204                         p = strchr(tok,'=');
 205                         if (!p) continue;
 206
 207                         *p = 0;
 208
 209                         variables[num_variables].name = strdup(tok);
 210                         variables[num_variables].value = strdup(p+1);
 211
 212                         if (!variables[num_variables].name ||
 213                             !variables[num_variables].value)
 214                                 continue;
 215
 216                         unescape(variables[num_variables].value);
 217                         unescape(variables[num_variables].name);
 218
 219 #ifdef DEBUG_COMMENTS
 220                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 221                                variables[num_variables].name,
 222                                variables[num_variables].value);
 223 #endif
 224                         num_variables++;
 225                         if (num_variables == MAX_VARIABLES) break;
 226                 }
 227
 228         }
 229 #ifdef DEBUG_COMMENTS
 230         printf("<!== End dump in cgi_load_variables() ==>\n");
 231 #endif
 232 }
 233
 234
 235 /***************************************************************************
 236   find a variable passed via CGI
 237   Doesn't quite do what you think in the case of POST text variables, because
 238   if they exist they might have a value of "" or even " ", depending on the
 239   browser. Also doesn't allow for variables[] containing multiple variables
 240   with the same name and the same or different values.
 241   ***************************************************************************/
 242 char *cgi_variable(char *name)
 243 {
 244         int i;
 245
 246         for (i=0;i<num_variables;i++)
 247                 if (strcmp(variables[i].name, name) == 0)
 248                         return variables[i].value;
 249         return NULL;
 250 }
 251
 252 /***************************************************************************
 253 tell a browser about a fatal error in the http processing
 254   ***************************************************************************/
 255 static void cgi_setup_error(char *err, char *header, char *info)
 256 {
 257         if (!got_request) {
 258                 /* damn browsers don't like getting cut off before they give a request */
 259                 char line[1024];
 260                 while (fgets(line, sizeof(line)-1, stdin)) {
 261                         if (strncasecmp(line,"GET ", 4)==0 ||
 262                             strncasecmp(line,"POST ", 5)==0 ||
 263                             strncasecmp(line,"PUT ", 4)==0) {
 264                                 break;
 265                         }
 266                 }
 267         }
 268
 269         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);
 270         fclose(stdin);
 271         fclose(stdout);
 272         exit(0);
 273 }
 274
 275
 276 /***************************************************************************
 277 tell a browser about a fatal authentication error
 278   ***************************************************************************/
 279 static void cgi_auth_error(void)
 280 {
 281         if (inetd_server) {
 282                 cgi_setup_error("401 Authorization Required",
 283                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 284                                 "You must be authenticated to use this service");
 285         } else {
 286                 printf("Content-Type: text/html\r\n");
 287
 288                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 289                 printf("<BODY><H1>Installation Error</H1>\n");
 290                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 291                 printf("</BODY></HTML>\r\n");
 292         }
 293         exit(0);
 294 }
 295
 296
 297 /***************************************************************************
 298 decode a base64 string in-place - simple and slow algorithm
 299   ***************************************************************************/
 300 static void base64_decode(char *s)
 301 {
 302         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 303         int bit_offset, byte_offset, idx, i, n;
 304         unsigned char *d = (unsigned char *)s;
 305         char *p;
 306
 307         n=i=0;
 308
 309         while (*s && (p=strchr(b64,*s))) {
 310                 idx = (int)(p - b64);
 311                 byte_offset = (i*6)/8;
 312                 bit_offset = (i*6)%8;
 313                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 314                 if (bit_offset < 3) {
 315                         d[byte_offset] |= (idx << (2-bit_offset));
 316                         n = byte_offset+1;
 317                 } else {
 318                         d[byte_offset] |= (idx >> (bit_offset-2));
 319                         d[byte_offset+1] = 0;
 320                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 321                         n = byte_offset+2;
 322                 }
 323                 s++; i++;
 324         }
 325         /* null terminate */
 326         d[n] = 0;
 327 }
 328
 329
 330 /***************************************************************************
 331 handle a http authentication line
 332   ***************************************************************************/
 333 static BOOL cgi_handle_authorization(char *line)
 334 {
 335         char *p, *user, *user_pass;
 336         struct passwd *pass = NULL;
 337         BOOL ret = False;
 338
 339         if (strncasecmp(line,"Basic ", 6)) {
 340                 cgi_setup_error("401 Bad Authorization", "",
 341                                 "Only basic authorization is understood");
 342                 return False;
 343         }
 344         line += 6;
 345         while (line[0] == ' ') line++;
 346         base64_decode(line);
 347         if (!(p=strchr(line,':'))) {
 348                 /*
 349                  * Always give the same error so a cracker
 350                  * cannot tell why we fail.
 351                  */
 352                 cgi_setup_error("401 Bad Authorization", "",
 353                                 "username/password must be supplied");
 354                 return False;
 355         }
 356         *p = 0;
 357         user = line;
 358         user_pass = p+1;
 359
 360         /*
 361          * Try and get the user from the UNIX password file.
 362          */
 363
 364         if(!(pass = Get_Pwnam(user,False))) {
 365                 /*
 366                  * Always give the same error so a cracker
 367                  * cannot tell why we fail.
 368                  */
 369                 cgi_setup_error("401 Bad Authorization", "",
 370                                 "username/password must be supplied");
 371                 return False;
 372         }
 373
 374         /*
 375          * Validate the password they have given.
 376          */
 377
 378         if((ret = pass_check(user, user_pass, strlen(user_pass), NULL, NULL)) == True) {
 379
 380                 /*
 381                  * Password was ok.
 382                  */
 383
 384                 if(pass->pw_uid != 0) {
 385                         /*
 386                          * We have not authenticated as root,
 387                          * become the user *permanently*.
 388                          */
 389                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 390                 }
 391
 392                 /* Save the users name */
 393                 C_user = strdup(user);
 394         }
 395
 396         return ret;
 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
 430         /* sanitise the filename */
 431         for (i=0;file[i];i++) {
 432                 if (!isalnum((int)file[i]) && !strchr("/.-_", file[i])) {
 433                         cgi_setup_error("404 File Not Found","",
 434                                         "Illegal character in filename");
 435                 }
 436         }
 437
 438         if (!file_exist(file, &st)) {
 439                 cgi_setup_error("404 File Not Found","",
 440                                 "The requested file was not found");
 441         }
 442         fd = sys_open(file,O_RDONLY,0);
 443         if (fd == -1) {
 444                 cgi_setup_error("404 File Not Found","",
 445                                 "The requested file was not found");
 446         }
 447         printf("HTTP/1.0 200 OK\r\n");
 448         if ((p=strrchr(file,'.'))) {
 449                 if (strcmp(p,".gif")==0) {
 450                         printf("Content-Type: image/gif\r\n");
 451                 } else if (strcmp(p,".jpg")==0) {
 452                         printf("Content-Type: image/jpeg\r\n");
 453                 } else {
 454                         printf("Content-Type: text/html\r\n");
 455                 }
 456         }
 457         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 458
 459         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 460         while ((l=read(fd,buf,sizeof(buf)))>0) {
 461                 fwrite(buf, 1, l, stdout);
 462         }
 463         close(fd);
 464         exit(0);
 465 }
 466
 467
 468 /***************************************************************************
 469 setup the cgi framework, handling the possability that this program is either
 470 run as a true cgi program by a web browser or is itself a mini web server
 471   ***************************************************************************/
 472 void cgi_setup(char *rootdir, int auth_required)
 473 {
 474         BOOL authenticated = False;
 475         char line[1024];
 476         char *url=NULL;
 477         char *p;
 478 #if CGI_LOGGING
 479         FILE *f;
 480 #endif
 481
 482         if (chdir(rootdir)) {
 483                 cgi_setup_error("400 Server Error", "",
 484                                 "chdir failed - the server is not configured correctly");
 485         }
 486
 487         /* maybe we are running under a web server */
 488         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 489                 if (auth_required) {
 490                         cgi_auth_error();
 491                 }
 492                 return;
 493         }
 494
 495         inetd_server = True;
 496
 497         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 498                 cgi_setup_error("400 Server Error", "",
 499                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 500         }
 501
 502 #if CGI_LOGGING
 503         f = sys_fopen("/tmp/cgi.log", "a");
 504         if (f) fprintf(f,"\n[Date: %s   %s (%s)]\n",
 505                        http_timestring(time(NULL)),
 506                        client_name(1), client_addr(1));
 507 #endif
 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 CGI_LOGGING
 513                 if (f) fputs(line, f);
 514 #endif
 515                 if (line[0] == '\r' || line[0] == '\n') break;
 516                 if (strncasecmp(line,"GET ", 4)==0) {
 517                         got_request = True;
 518                         url = strdup(&line[4]);
 519                 } else if (strncasecmp(line,"POST ", 5)==0) {
 520                         got_request = True;
 521                         request_post = 1;
 522                         url = strdup(&line[5]);
 523                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 524                         got_request = True;
 525                         cgi_setup_error("400 Bad Request", "",
 526                                         "This server does not accept PUT requests");
 527                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 528                         authenticated = cgi_handle_authorization(&line[15]);
 529                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 530                         content_length = atoi(&line[16]);
 531                 }
 532                 /* ignore all other requests! */
 533         }
 534 #if CGI_LOGGING
 535         if (f) fclose(f);
 536 #endif
 537
 538         if (auth_required && !authenticated) {
 539                 cgi_auth_error();
 540         }
 541
 542         if (!url) {
 543                 cgi_setup_error("400 Bad Request", "",
 544                                 "You must specify a GET or POST request");
 545         }
 546
 547         /* trim the URL */
 548         if ((p = strchr(url,' ')) || (p=strchr(url,'\t'))) {
 549                 *p = 0;
 550         }
 551         while (*url && strchr("\r\n",url[strlen(url)-1])) {
 552                 url[strlen(url)-1] = 0;
 553         }
 554
 555         /* anything following a ? in the URL is part of the query string */
 556         if ((p=strchr(url,'?'))) {
 557                 query_string = p+1;
 558                 *p = 0;
 559         }
 560
 561         string_sub(url, "/swat/", "", 0);
 562
 563         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 564                 cgi_download(url);
 565         }
 566
 567         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 568         printf("Date: %s\r\n", http_timestring(time(NULL)));
 569         baseurl = "";
 570         pathinfo = url+1;
 571 }
 572
 573
 574 /***************************************************************************
 575 return the current pages URL
 576   ***************************************************************************/
 577 char *cgi_baseurl(void)
 578 {
 579         if (inetd_server) {
 580                 return baseurl;
 581         }
 582         return getenv("SCRIPT_NAME");
 583 }
 584
 585 /***************************************************************************
 586 return the current pages path info
 587   ***************************************************************************/
 588 char *cgi_pathinfo(void)
 589 {
 590         char *r;
 591         if (inetd_server) {
 592                 return pathinfo;
 593         }
 594         r = getenv("PATH_INFO");
 595         if (!r) return "";
 596         if (*r == '/') r++;
 597         return r;
 598 }
 599
 600 /***************************************************************************
 601 return the hostname of the client
 602   ***************************************************************************/
 603 char *cgi_remote_host(void)
 604 {
 605         if (inetd_server) {
 606                 return client_name(1);
 607         }
 608         return getenv("REMOTE_HOST");
 609 }
 610
 611 /***************************************************************************
 612 return the hostname of the client
 613   ***************************************************************************/
 614 char *cgi_remote_addr(void)
 615 {
 616         if (inetd_server) {
 617                 return client_addr(1);
 618         }
 619         return getenv("REMOTE_ADDR");
 620 }
 621
 622
 623 /***************************************************************************
 624 return True if the request was a POST
 625   ***************************************************************************/
 626 BOOL cgi_waspost(void)
 627 {
 628         if (inetd_server) {
 629                 return request_post;
 630         }
 631         return strequal(getenv("REQUEST_METHOD"), "POST");
 632 }