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 "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
  49 static void unescape(char *buf)
  50 {
  51         char *p=buf;
  52
  53         while ((p=strchr(p,'+')))
  54                 *p = ' ';
  55
  56         p = buf;
  57
  58         while (p && *p && (p=strchr(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;
  89         int i = 0;
  90         int len = 1024;
  91
  92         ret = (char *)malloc(len);
  93         if (!ret) return NULL;
  94
  95
  96         while ((*cl)) {
  97                 int c = fgetc(f);
  98                 (*cl)--;
  99
 100                 if (c == EOF) {
 101                         (*cl) = 0;
 102                         break;
 103                 }
 104
 105                 if (c == '\r') continue;
 106
 107                 if (strchr("\n&", c)) break;
 108
 109                 ret[i++] = c;
 110
 111                 if (i == len-1) {
 112                         char *ret2;
 113                         ret2 = (char *)realloc(ret, len*2);
 114                         if (!ret2) return ret;
 115                         len *= 2;
 116                         ret = ret2;
 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(FILE *f1)
 131 {
 132         FILE *f = f1;
 133         static char *line;
 134         char *p, *s, *tok;
 135         int len;
 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 (!f1) {
 144                 f = stdin;
 145                 if (!content_length) {
 146                         p = getenv("CONTENT_LENGTH");
 147                         len = p?atoi(p):0;
 148                 } else {
 149                         len = content_length;
 150                 }
 151         } else {
 152                 fseek(f, 0, SEEK_END);
 153                 len = ftell(f);
 154                 fseek(f, 0, SEEK_SET);
 155         }
 156
 157
 158         if (len > 0 &&
 159             (f1 || request_post ||
 160              ((s=getenv("REQUEST_METHOD")) &&
 161               strcasecmp(s,"POST")==0))) {
 162                 while (len && (line=grab_line(f, &len))) {
 163                         p = strchr(line,'=');
 164                         if (!p) continue;
 165
 166                         *p = 0;
 167
 168                         variables[num_variables].name = strdup(line);
 169                         variables[num_variables].value = strdup(p+1);
 170
 171                         free(line);
 172
 173                         if (!variables[num_variables].name ||
 174                             !variables[num_variables].value)
 175                                 continue;
 176
 177                         unescape(variables[num_variables].value);
 178                         unescape(variables[num_variables].name);
 179
 180 #ifdef DEBUG_COMMENTS
 181                         printf("<!== POST var %s has value \"%s\"  ==>\n",
 182                                variables[num_variables].name,
 183                                variables[num_variables].value);
 184 #endif
 185
 186                         num_variables++;
 187                         if (num_variables == MAX_VARIABLES) break;
 188                 }
 189         }
 190
 191         if (f1) {
 192 #ifdef DEBUG_COMMENTS
 193                 printf("<!== End dump in cgi_load_variables() ==>\n");
 194 #endif
 195                 return;
 196         }
 197
 198         fclose(stdin);
 199
 200         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 201                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 202                         p = strchr(tok,'=');
 203                         if (!p) continue;
 204
 205                         *p = 0;
 206
 207                         variables[num_variables].name = strdup(tok);
 208                         variables[num_variables].value = strdup(p+1);
 209
 210                         if (!variables[num_variables].name ||
 211                             !variables[num_variables].value)
 212                                 continue;
 213
 214                         unescape(variables[num_variables].value);
 215                         unescape(variables[num_variables].name);
 216
 217 #ifdef DEBUG_COMMENTS
 218                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 219                                variables[num_variables].name,
 220                                variables[num_variables].value);
 221 #endif
 222                         num_variables++;
 223                         if (num_variables == MAX_VARIABLES) break;
 224                 }
 225
 226         }
 227 #ifdef DEBUG_COMMENTS
 228         printf("<!== End dump in cgi_load_variables() ==>\n");
 229 #endif
 230 }
 231
 232
 233 /***************************************************************************
 234   find a variable passed via CGI
 235   Doesn't quite do what you think in the case of POST text variables, because
 236   if they exist they might have a value of "" or even " ", depending on the
 237   browser. Also doesn't allow for variables[] containing multiple variables
 238   with the same name and the same or different values.
 239   ***************************************************************************/
 240 char *cgi_variable(char *name)
 241 {
 242         int i;
 243
 244         for (i=0;i<num_variables;i++)
 245                 if (strcmp(variables[i].name, name) == 0)
 246                         return variables[i].value;
 247         return NULL;
 248 }
 249
 250 /***************************************************************************
 251 tell a browser about a fatal error in the http processing
 252   ***************************************************************************/
 253 static void cgi_setup_error(char *err, char *header, char *info)
 254 {
 255         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", err, header, err, err, info);
 256         exit(0);
 257 }
 258
 259
 260 /***************************************************************************
 261 decode a base64 string in-place - simple and slow algorithm
 262   ***************************************************************************/
 263 static void base64_decode(char *s)
 264 {
 265         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 266         int bit_offset, byte_offset, idx, i, n;
 267         unsigned char *d = (unsigned char *)s;
 268         char *p;
 269
 270         n=i=0;
 271
 272         while (*s && (p=strchr(b64,*s))) {
 273                 idx = (int)(p - b64);
 274                 byte_offset = (i*6)/8;
 275                 bit_offset = (i*6)%8;
 276                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 277                 if (bit_offset < 3) {
 278                         d[byte_offset] |= (idx << (2-bit_offset));
 279                         n = byte_offset+1;
 280                 } else {
 281                         d[byte_offset] |= (idx >> (bit_offset-2));
 282                         d[byte_offset+1] = 0;
 283                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 284                         n = byte_offset+2;
 285                 }
 286                 s++; i++;
 287         }
 288         /* null terminate */
 289         d[n] = 0;
 290 }
 291
 292
 293 /***************************************************************************
 294 handle a http authentication line
 295   ***************************************************************************/
 296 static BOOL cgi_handle_authorization(char *line)
 297 {
 298         char *p, *user, *user_pass;
 299         struct passwd *pass = NULL;
 300         int ret = False;
 301
 302         if (strncasecmp(line,"Basic ", 6)) {
 303                 cgi_setup_error("401 Bad Authorization", "",
 304                                 "Only basic authorization is understood");
 305                 return False;
 306         }
 307         line += 6;
 308         while (line[0] == ' ') line++;
 309         base64_decode(line);
 310         if (!(p=strchr(line,':'))) {
 311                 /*
 312                  * Always give the same error so a cracker
 313                  * cannot tell why we fail.
 314                  */
 315                 cgi_setup_error("401 Bad Authorization", "",
 316                                 "username/password must be supplied");
 317                 return False;
 318         }
 319         *p = 0;
 320         user = line;
 321         user_pass = p+1;
 322
 323         /*
 324          * Try and get the user from the UNIX password file.
 325          */
 326
 327         if(!(pass = Get_Pwnam(user,False))) {
 328                 /*
 329                  * Always give the same error so a cracker
 330                  * cannot tell why we fail.
 331                  */
 332                 cgi_setup_error("401 Bad Authorization", "",
 333                                 "username/password must be supplied");
 334                 return False;
 335         }
 336
 337         /*
 338          * Validate the password they have given.
 339          */
 340
 341         if((ret = pass_check(user, user_pass, strlen(user_pass), NULL, NULL)) == True) {
 342
 343                 /*
 344                  * Password was ok.
 345                  */
 346
 347                 if(pass->pw_uid != 0) {
 348                         /*
 349                          * We have not authenticated as root,
 350                          * become the user *permanently*.
 351                          */
 352                         if(!become_user_permanently(pass->pw_uid, pass->pw_gid)) {
 353                                 /*
 354                                  * Always give the same error so a cracker
 355                                  * cannot tell why we fail.
 356                                  */
 357                                 cgi_setup_error("401 Bad Authorization", "",
 358                         "username/password must be supplied");
 359                         return False;
 360                         }
 361
 362                         /*
 363                          * On exit from here we are the authenticated
 364                          * user - no way back.
 365                          */
 366                 }
 367
 368                 /* Save the users name */
 369                 C_user = strdup(user);
 370         }
 371
 372         return ret;
 373 }
 374
 375 /***************************************************************************
 376 is this root?
 377   ***************************************************************************/
 378 BOOL am_root(void)
 379 {
 380         if (geteuid() == 0) {
 381                 return( True);
 382         } else {
 383                 return( False);
 384         }
 385 }
 386
 387 /***************************************************************************
 388 return a ptr to the users name
 389   ***************************************************************************/
 390 char *get_user_name(void)
 391 {
 392         return(C_user);
 393 }
 394
 395
 396 /***************************************************************************
 397 handle a file download
 398   ***************************************************************************/
 399 static void cgi_download(char *file)
 400 {
 401         SMB_STRUCT_STAT st;
 402         char buf[1024];
 403         int fd, l, i;
 404         char *p;
 405
 406         /* sanitise the filename */
 407         for (i=0;file[i];i++) {
 408                 if (!isalnum((int)file[i]) && !strchr("/.-_", file[i])) {
 409                         cgi_setup_error("404 File Not Found","",
 410                                         "Illegal character in filename");
 411                 }
 412         }
 413
 414         if (!file_exist(file, &st)) {
 415                 cgi_setup_error("404 File Not Found","",
 416                                 "The requested file was not found");
 417         }
 418         fd = open(file,O_RDONLY);
 419         if (fd == -1) {
 420                 cgi_setup_error("404 File Not Found","",
 421                                 "The requested file was not found");
 422         }
 423         printf("HTTP/1.0 200 OK\r\n");
 424         if ((p=strrchr(file,'.'))) {
 425                 if (strcmp(p,".gif")==0) {
 426                         printf("Content-Type: image/gif\r\n");
 427                 } else if (strcmp(p,".jpg")==0) {
 428                         printf("Content-Type: image/jpeg\r\n");
 429                 } else {
 430                         printf("Content-Type: text/html\r\n");
 431                 }
 432         }
 433         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 434
 435         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 436         while ((l=read(fd,buf,sizeof(buf)))>0) {
 437                 fwrite(buf, 1, l, stdout);
 438         }
 439         close(fd);
 440         exit(0);
 441 }
 442
 443
 444 /***************************************************************************
 445 setup the cgi framework, handling the possability that this program is either
 446 run as a true cgi program by a web browser or is itself a mini web server
 447   ***************************************************************************/
 448 void cgi_setup(char *rootdir, int auth_required)
 449 {
 450         BOOL authenticated = False;
 451         char line[1024];
 452         char *url=NULL;
 453         char *p;
 454 #if CGI_LOGGING
 455         FILE *f;
 456 #endif
 457
 458         if (chdir(rootdir)) {
 459                 cgi_setup_error("400 Server Error", "",
 460                                 "chdir failed - the server is not configured correctly");
 461         }
 462
 463         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 464
 465                 char *x;
 466
 467                 /* Save the users name if available */
 468                 if ((x = getenv("REMOTE_USER"))) {
 469                         C_user = strdup(x);
 470                 } else {
 471                         C_user = "";
 472                 }
 473
 474                 /* assume we are running under a real web server */
 475                 return;
 476         }
 477
 478 #if CGI_LOGGING
 479         f = fopen("/tmp/cgi.log", "a");
 480         if (f) fprintf(f,"\n[Date: %s   %s (%s)]\n",
 481                        http_timestring(time(NULL)),
 482                        client_name(1), client_addr(1));
 483 #endif
 484
 485         /* we are a mini-web server. We need to read the request from stdin
 486            and handle authentication etc */
 487         while (fgets(line, sizeof(line)-1, stdin)) {
 488 #if CGI_LOGGING
 489                 if (f) fputs(line, f);
 490 #endif
 491                 if (line[0] == '\r' || line[0] == '\n') break;
 492                 if (strncasecmp(line,"GET ", 4)==0) {
 493                         url = strdup(&line[4]);
 494                 } else if (strncasecmp(line,"POST ", 5)==0) {
 495                         request_post = 1;
 496                         url = strdup(&line[5]);
 497                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 498                         cgi_setup_error("400 Bad Request", "",
 499                                         "This server does not accept PUT requests");
 500                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 501                         authenticated = cgi_handle_authorization(&line[15]);
 502                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 503                         content_length = atoi(&line[16]);
 504                 }
 505                 /* ignore all other requests! */
 506         }
 507 #if CGI_LOGGING
 508         if (f) fclose(f);
 509 #endif
 510
 511         if (auth_required && !authenticated) {
 512                 cgi_setup_error("401 Authorization Required",
 513                                 "WWW-Authenticate: Basic realm=\"root\"\r\n",
 514                                 "You must be authenticated to use this service");
 515         }
 516
 517         if (!url) {
 518                 cgi_setup_error("400 Bad Request", "",
 519                                 "You must specify a GET or POST request");
 520         }
 521
 522         /* trim the URL */
 523         if ((p = strchr(url,' ')) || (p=strchr(url,'\t'))) {
 524                 *p = 0;
 525         }
 526         while (*url && strchr("\r\n",url[strlen(url)-1])) {
 527                 url[strlen(url)-1] = 0;
 528         }
 529
 530         /* anything following a ? in the URL is part of the query string */
 531         if ((p=strchr(url,'?'))) {
 532                 query_string = p+1;
 533                 *p = 0;
 534         }
 535
 536         string_sub(url, "/swat/", "");
 537
 538         if (strstr(url,"..")==0 && file_exist(url, NULL)) {
 539                 cgi_download(url);
 540         }
 541
 542         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 543         printf("Date: %s\r\n", http_timestring(time(NULL)));
 544         baseurl = "";
 545         pathinfo = url+1;
 546 }
 547
 548
 549 /***************************************************************************
 550 return the current pages URL
 551   ***************************************************************************/
 552 char *cgi_baseurl(void)
 553 {
 554         if (baseurl) {
 555                 return baseurl;
 556         }
 557         return getenv("SCRIPT_NAME");
 558 }
 559
 560 /***************************************************************************
 561 return the current pages path info
 562   ***************************************************************************/
 563 char *cgi_pathinfo(void)
 564 {
 565         char *r;
 566         if (pathinfo) {
 567                 return pathinfo;
 568         }
 569         r = getenv("PATH_INFO");
 570         if (!r) return "";
 571         if (*r == '/') r++;
 572         return r;
 573 }
 574
 575 /***************************************************************************
 576 return the hostname of the client
 577   ***************************************************************************/
 578 char *cgi_remote_host(void)
 579 {
 580         if (baseurl) {
 581                 return client_name(1);
 582         }
 583         return getenv("REMOTE_HOST");
 584 }
 585
 586 /***************************************************************************
 587 return the hostname of the client
 588   ***************************************************************************/
 589 char *cgi_remote_addr(void)
 590 {
 591         if (baseurl) {
 592                 return client_addr(1);
 593         }
 594         return getenv("REMOTE_ADDR");
 595 }
 596
 597
 598 /***************************************************************************
 599 return True if the request was a POST
 600   ***************************************************************************/
 601 BOOL cgi_waspost(void)
 602 {
 603         if (baseurl) {
 604                 return request_post;
 605         }
 606         return strequal(getenv("REQUEST_METHOD"), "POST");
 607 }