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 #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(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         open("/dev/null", O_RDWR);
 200
 201         if ((s=query_string) || (s=getenv("QUERY_STRING"))) {
 202                 for (tok=strtok(s,"&;");tok;tok=strtok(NULL,"&;")) {
 203                         p = strchr(tok,'=');
 204                         if (!p) continue;
 205
 206                         *p = 0;
 207
 208                         variables[num_variables].name = strdup(tok);
 209                         variables[num_variables].value = strdup(p+1);
 210
 211                         if (!variables[num_variables].name ||
 212                             !variables[num_variables].value)
 213                                 continue;
 214
 215                         unescape(variables[num_variables].value);
 216                         unescape(variables[num_variables].name);
 217
 218 #ifdef DEBUG_COMMENTS
 219                         printf("<!== Commandline var %s has value \"%s\"  ==>\n",
 220                                variables[num_variables].name,
 221                                variables[num_variables].value);
 222 #endif
 223                         num_variables++;
 224                         if (num_variables == MAX_VARIABLES) break;
 225                 }
 226
 227         }
 228 #ifdef DEBUG_COMMENTS
 229         printf("<!== End dump in cgi_load_variables() ==>\n");
 230 #endif
 231 }
 232
 233
 234 /***************************************************************************
 235   find a variable passed via CGI
 236   Doesn't quite do what you think in the case of POST text variables, because
 237   if they exist they might have a value of "" or even " ", depending on the
 238   browser. Also doesn't allow for variables[] containing multiple variables
 239   with the same name and the same or different values.
 240   ***************************************************************************/
 241 char *cgi_variable(char *name)
 242 {
 243         int i;
 244
 245         for (i=0;i<num_variables;i++)
 246                 if (strcmp(variables[i].name, name) == 0)
 247                         return variables[i].value;
 248         return NULL;
 249 }
 250
 251 /***************************************************************************
 252 tell a browser about a fatal error in the http processing
 253   ***************************************************************************/
 254 static void cgi_setup_error(char *err, char *header, char *info)
 255 {
 256         if (!got_request) {
 257                 /* damn browsers don't like getting cut off before they give a request */
 258                 char line[1024];
 259                 while (fgets(line, sizeof(line)-1, stdin)) {
 260                         if (strncasecmp(line,"GET ", 4)==0 ||
 261                             strncasecmp(line,"POST ", 5)==0 ||
 262                             strncasecmp(line,"PUT ", 4)==0) {
 263                                 break;
 264                         }
 265                 }
 266         }
 267
 268         printf("HTTP/1.0 %s\r\n%sConnection: close\r\nContent-Type: text/html\r\n\r\n<HTML><HEAD><TITLE>%s</TITLE></HEAD><BODY><H1>%s</H1>%s<p></BODY></HTML>\r\n\r\n", err, header, err, err, info);
 269         fclose(stdin);
 270         fclose(stdout);
 271         exit(0);
 272 }
 273
 274
 275 /***************************************************************************
 276 tell a browser about a fatal authentication error
 277   ***************************************************************************/
 278 static void cgi_auth_error(void)
 279 {
 280         if (inetd_server) {
 281                 cgi_setup_error("401 Authorization Required",
 282                                 "WWW-Authenticate: Basic realm=\"SWAT\"\r\n",
 283                                 "You must be authenticated to use this service");
 284         } else {
 285                 printf("Content-Type: text/html\r\n");
 286
 287                 printf("\r\n<HTML><HEAD><TITLE>SWAT</TITLE></HEAD>\n");
 288                 printf("<BODY><H1>Installation Error</H1>\n");
 289                 printf("SWAT must be installed via inetd. It cannot be run as a CGI script<p>\n");
 290                 printf("</BODY></HTML>\r\n");
 291         }
 292         exit(0);
 293 }
 294
 295
 296 /***************************************************************************
 297 decode a base64 string in-place - simple and slow algorithm
 298   ***************************************************************************/
 299 static void base64_decode(char *s)
 300 {
 301         char *b64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 302         int bit_offset, byte_offset, idx, i, n;
 303         unsigned char *d = (unsigned char *)s;
 304         char *p;
 305
 306         n=i=0;
 307
 308         while (*s && (p=strchr(b64,*s))) {
 309                 idx = (int)(p - b64);
 310                 byte_offset = (i*6)/8;
 311                 bit_offset = (i*6)%8;
 312                 d[byte_offset] &= ~((1<<(8-bit_offset))-1);
 313                 if (bit_offset < 3) {
 314                         d[byte_offset] |= (idx << (2-bit_offset));
 315                         n = byte_offset+1;
 316                 } else {
 317                         d[byte_offset] |= (idx >> (bit_offset-2));
 318                         d[byte_offset+1] = 0;
 319                         d[byte_offset+1] |= (idx << (8-(bit_offset-2))) & 0xFF;
 320                         n = byte_offset+2;
 321                 }
 322                 s++; i++;
 323         }
 324         /* null terminate */
 325         d[n] = 0;
 326 }
 327
 328 /***************************************************************************
 329 handle a http authentication line
 330   ***************************************************************************/
 331 static BOOL cgi_handle_authorization(char *line)
 332 {
 333         char *p, *user, *user_pass;
 334         struct passwd *pass = NULL;
 335         BOOL got_name = False;
 336         BOOL tested_pass = False;
 337         fstring default_user_lookup;
 338         fstring default_user_pass;
 339
 340         /* Dummy user lookup to take the same time as a valid user. */
 341         fstrcpy(default_user_lookup, "zzzz bibble");
 342         fstrcpy(default_user_pass, "123456789");
 343
 344         if (strncasecmp(line,"Basic ", 6)) {
 345                 goto err;
 346         }
 347         line += 6;
 348         while (line[0] == ' ') line++;
 349         base64_decode(line);
 350         if (!(p=strchr(line,':'))) {
 351                 /*
 352                  * Always give the same error so a cracker
 353                  * cannot tell why we fail.
 354                  */
 355                 goto err;
 356         }
 357         *p = 0;
 358         user = line;
 359         user_pass = p+1;
 360
 361         /*
 362          * Try and get the user from the UNIX password file.
 363          */
 364
 365         if(!(pass = Get_Pwnam(user,False))) {
 366                 /*
 367                  * Always give the same error so a cracker
 368                  * cannot tell why we fail.
 369                  */
 370                 got_name = True;
 371                 goto err;
 372         }
 373
 374         /*
 375          * Validate the password they have given.
 376          */
 377
 378         tested_pass = True;
 379
 380         if(pass_check(user, user_pass, strlen(user_pass), NULL, NULL) == True) {
 381
 382                 /*
 383                  * Password was ok.
 384                  */
 385
 386                 if(pass->pw_uid != 0) {
 387                         /*
 388                          * We have not authenticated as root,
 389                          * become the user *permanently*.
 390                          */
 391                         become_user_permanently(pass->pw_uid, pass->pw_gid);
 392                 }
 393
 394                 /* Save the users name */
 395                 C_user = strdup(user);
 396                 return True;
 397         }
 398
 399   err:
 400
 401         /* Always take the same time. */
 402         if (!got_name)
 403                 Get_Pwnam(default_user_lookup,False);
 404
 405         if (!tested_pass)
 406                 pass_check(default_user_lookup, default_user_pass,
 407                                         strlen(default_user_pass), NULL, NULL);
 408
 409         cgi_setup_error("401 Bad Authorization", "",
 410                         "username or password incorrect");
 411
 412         return False;
 413 }
 414
 415 /***************************************************************************
 416 is this root?
 417   ***************************************************************************/
 418 BOOL am_root(void)
 419 {
 420         if (geteuid() == 0) {
 421                 return( True);
 422         } else {
 423                 return( False);
 424         }
 425 }
 426
 427 /***************************************************************************
 428 return a ptr to the users name
 429   ***************************************************************************/
 430 char *cgi_user_name(void)
 431 {
 432         return(C_user);
 433 }
 434
 435
 436 /***************************************************************************
 437 handle a file download
 438   ***************************************************************************/
 439 static void cgi_download(char *file)
 440 {
 441         SMB_STRUCT_STAT st;
 442         char buf[1024];
 443         int fd, l, i;
 444         char *p;
 445
 446         /* sanitise the filename */
 447         for (i=0;file[i];i++) {
 448                 if (!isalnum((int)file[i]) && !strchr("/.-_", file[i])) {
 449                         cgi_setup_error("404 File Not Found","",
 450                                         "Illegal character in filename");
 451                 }
 452         }
 453
 454         if (!file_exist(file, &st)) {
 455                 cgi_setup_error("404 File Not Found","",
 456                                 "The requested file was not found");
 457         }
 458         fd = sys_open(file,O_RDONLY,0);
 459         if (fd == -1) {
 460                 cgi_setup_error("404 File Not Found","",
 461                                 "The requested file was not found");
 462         }
 463         printf("HTTP/1.0 200 OK\r\n");
 464         if ((p=strrchr(file,'.'))) {
 465                 if (strcmp(p,".gif")==0) {
 466                         printf("Content-Type: image/gif\r\n");
 467                 } else if (strcmp(p,".jpg")==0) {
 468                         printf("Content-Type: image/jpeg\r\n");
 469                 } else if (strcmp(p,".txt")==0) {
 470                         printf("Content-Type: text/plain\r\n");
 471                 } else {
 472                         printf("Content-Type: text/html\r\n");
 473                 }
 474         }
 475         printf("Expires: %s\r\n", http_timestring(time(NULL)+EXPIRY_TIME));
 476
 477         printf("Content-Length: %d\r\n\r\n", (int)st.st_size);
 478         while ((l=read(fd,buf,sizeof(buf)))>0) {
 479                 fwrite(buf, 1, l, stdout);
 480         }
 481         close(fd);
 482         exit(0);
 483 }
 484
 485
 486 /***************************************************************************
 487 setup the cgi framework, handling the possability that this program is either
 488 run as a true cgi program by a web browser or is itself a mini web server
 489   ***************************************************************************/
 490 void cgi_setup(char *rootdir, int auth_required)
 491 {
 492         BOOL authenticated = False;
 493         char line[1024];
 494         char *url=NULL;
 495         char *p;
 496
 497         if (chdir(rootdir)) {
 498                 cgi_setup_error("400 Server Error", "",
 499                                 "chdir failed - the server is not configured correctly");
 500         }
 501
 502         /* maybe we are running under a web server */
 503         if (getenv("CONTENT_LENGTH") || getenv("REQUEST_METHOD")) {
 504                 if (auth_required) {
 505                         cgi_auth_error();
 506                 }
 507                 return;
 508         }
 509
 510         inetd_server = True;
 511
 512         if (!check_access(1, lp_hostsallow(-1), lp_hostsdeny(-1))) {
 513                 cgi_setup_error("400 Server Error", "",
 514                                 "Samba is configured to deny access from this client\n<br>Check your \"hosts allow\" and \"hosts deny\" options in smb.conf ");
 515         }
 516
 517         /* we are a mini-web server. We need to read the request from stdin
 518            and handle authentication etc */
 519         while (fgets(line, sizeof(line)-1, stdin)) {
 520                 if (line[0] == '\r' || line[0] == '\n') break;
 521                 if (strncasecmp(line,"GET ", 4)==0) {
 522                         got_request = True;
 523                         url = strdup(&line[4]);
 524                 } else if (strncasecmp(line,"POST ", 5)==0) {
 525                         got_request = True;
 526                         request_post = 1;
 527                         url = strdup(&line[5]);
 528                 } else if (strncasecmp(line,"PUT ", 4)==0) {
 529                         got_request = True;
 530                         cgi_setup_error("400 Bad Request", "",
 531                                         "This server does not accept PUT requests");
 532                 } else if (strncasecmp(line,"Authorization: ", 15)==0) {
 533                         authenticated = cgi_handle_authorization(&line[15]);
 534                 } else if (strncasecmp(line,"Content-Length: ", 16)==0) {
 535                         content_length = atoi(&line[16]);
 536                 }
 537                 /* ignore all other requests! */
 538         }
 539
 540         if (auth_required && !authenticated) {
 541                 cgi_auth_error();
 542         }
 543
 544         if (!url) {
 545                 cgi_setup_error("400 Bad Request", "",
 546                                 "You must specify a GET or POST request");
 547         }
 548
 549         /* trim the URL */
 550         if ((p = strchr(url,' ')) || (p=strchr(url,'\t'))) {
 551                 *p = 0;
 552         }
 553         while (*url && strchr("\r\n",url[strlen(url)-1])) {
 554                 url[strlen(url)-1] = 0;
 555         }
 556
 557         /* anything following a ? in the URL is part of the query string */
 558         if ((p=strchr(url,'?'))) {
 559                 query_string = p+1;
 560                 *p = 0;
 561         }
 562
 563         string_sub(url, "/swat/", "", 0);
 564
 565         if (url[0] != '/' && strstr(url,"..")==0 && file_exist(url, NULL)) {
 566                 cgi_download(url);
 567         }
 568
 569         printf("HTTP/1.0 200 OK\r\nConnection: close\r\n");
 570         printf("Date: %s\r\n", http_timestring(time(NULL)));
 571         baseurl = "";
 572         pathinfo = url+1;
 573 }
 574
 575
 576 /***************************************************************************
 577 return the current pages URL
 578   ***************************************************************************/
 579 char *cgi_baseurl(void)
 580 {
 581         if (inetd_server) {
 582                 return baseurl;
 583         }
 584         return getenv("SCRIPT_NAME");
 585 }
 586
 587 /***************************************************************************
 588 return the current pages path info
 589   ***************************************************************************/
 590 char *cgi_pathinfo(void)
 591 {
 592         char *r;
 593         if (inetd_server) {
 594                 return pathinfo;
 595         }
 596         r = getenv("PATH_INFO");
 597         if (!r) return "";
 598         if (*r == '/') r++;
 599         return r;
 600 }
 601
 602 /***************************************************************************
 603 return the hostname of the client
 604   ***************************************************************************/
 605 char *cgi_remote_host(void)
 606 {
 607         if (inetd_server) {
 608                 return get_socket_name(1);
 609         }
 610         return getenv("REMOTE_HOST");
 611 }
 612
 613 /***************************************************************************
 614 return the hostname of the client
 615   ***************************************************************************/
 616 char *cgi_remote_addr(void)
 617 {
 618         if (inetd_server) {
 619                 return get_socket_addr(1);
 620         }
 621         return getenv("REMOTE_ADDR");
 622 }
 623
 624
 625 /***************************************************************************
 626 return True if the request was a POST
 627   ***************************************************************************/
 628 BOOL cgi_waspost(void)
 629 {
 630         if (inetd_server) {
 631                 return request_post;
 632         }
 633         return strequal(getenv("REQUEST_METHOD"), "POST");
 634 }