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