contrib/tcp_wrappers/tcpdchk.c

   1  /*
   2   * tcpdchk - examine all tcpd access control rules and inetd.conf entries
   3   *
   4   * Usage: tcpdchk [-a] [-d] [-i inet_conf] [-v]
   5   *
   6   * -a: complain about implicit "allow" at end of rule.
   7   *
   8   * -d: rules in current directory.
   9   *
  10   * -i: location of inetd.conf file.
  11   *
  12   * -v: show all rules.
  13   *
  14   * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
  15   *
  16   * $FreeBSD$
  17   */
  18
  19 #ifndef lint
  20 static char sccsid[] = "@(#) tcpdchk.c 1.8 97/02/12 02:13:25";
  21 #endif
  22
  23 /* System libraries. */
  24
  25 #include <sys/types.h>
  26 #include <sys/stat.h>
  27 #ifdef INET6
  28 #include <sys/socket.h>
  29 #endif
  30 #include <netinet/in.h>
  31 #include <arpa/inet.h>
  32 #include <stdio.h>
  33 #include <syslog.h>
  34 #include <setjmp.h>
  35 #include <errno.h>
  36 #include <netdb.h>
  37 #include <string.h>
  38
  39 extern int errno;
  40 extern void exit();
  41 extern int optind;
  42 extern char *optarg;
  43
  44 #ifndef INADDR_NONE
  45 #define INADDR_NONE     (-1)            /* XXX should be 0xffffffff */
  46 #endif
  47
  48 #ifndef S_ISDIR
  49 #define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
  50 #endif
  51
  52 /* Application-specific. */
  53
  54 #include "tcpd.h"
  55 #include "inetcf.h"
  56 #include "scaffold.h"
  57
  58  /*
  59   * Stolen from hosts_access.c...
  60   */
  61 static char sep[] = ", \t\n";
  62
  63 #define BUFLEN 2048
  64
  65 int     resident = 0;
  66 int     hosts_access_verbose = 0;
  67 char   *hosts_allow_table = HOSTS_ALLOW;
  68 char   *hosts_deny_table = HOSTS_DENY;
  69 extern jmp_buf tcpd_buf;
  70
  71  /*
  72   * Local stuff.
  73   */
  74 static void usage();
  75 static void parse_table();
  76 static void print_list();
  77 static void check_daemon_list();
  78 static void check_client_list();
  79 static void check_daemon();
  80 static void check_user();
  81 static int check_host();
  82 static int reserved_name();
  83
  84 #define PERMIT  1
  85 #define DENY    0
  86
  87 #define YES     1
  88 #define NO      0
  89
  90 static int defl_verdict;
  91 static char *myname;
  92 static int allow_check;
  93 static char *inetcf;
  94
  95 int     main(argc, argv)
  96 int     argc;
  97 char  **argv;
  98 {
  99     struct request_info request;
 100     struct stat st;
 101     int     c;
 102
 103     myname = argv[0];
 104
 105     /*
 106      * Parse the JCL.
 107      */
 108     while ((c = getopt(argc, argv, "adi:v")) != EOF) {
 109         switch (c) {
 110         case 'a':
 111             allow_check = 1;
 112             break;
 113         case 'd':
 114             hosts_allow_table = "hosts.allow";
 115             hosts_deny_table = "hosts.deny";
 116             break;
 117         case 'i':
 118             inetcf = optarg;
 119             break;
 120         case 'v':
 121             hosts_access_verbose++;
 122             break;
 123         default:
 124             usage();
 125             /* NOTREACHED */
 126         }
 127     }
 128     if (argc != optind)
 129         usage();
 130
 131     /*
 132      * When confusion really strikes...
 133      */
 134     if (check_path(REAL_DAEMON_DIR, &st) < 0) {
 135         tcpd_warn("REAL_DAEMON_DIR %s: %m", REAL_DAEMON_DIR);
 136     } else if (!S_ISDIR(st.st_mode)) {
 137         tcpd_warn("REAL_DAEMON_DIR %s is not a directory", REAL_DAEMON_DIR);
 138     }
 139
 140     /*
 141      * Process the inet configuration file (or its moral equivalent). This
 142      * information is used later to find references in hosts.allow/deny to
 143      * unwrapped services, and other possible problems.
 144      */
 145     inetcf = inet_cfg(inetcf);
 146     if (hosts_access_verbose)
 147         printf("Using network configuration file: %s\n", inetcf);
 148
 149     /*
 150      * These are not run from inetd but may have built-in access control.
 151      */
 152     inet_set("portmap", WR_NOT);
 153     inet_set("rpcbind", WR_NOT);
 154
 155     /*
 156      * Check accessibility of access control files.
 157      */
 158     (void) check_path(hosts_allow_table, &st);
 159     (void) check_path(hosts_deny_table, &st);
 160
 161     /*
 162      * Fake up an arbitrary service request.
 163      */
 164     request_init(&request,
 165                  RQ_DAEMON, "daemon_name",
 166                  RQ_SERVER_NAME, "server_hostname",
 167                  RQ_SERVER_ADDR, "server_addr",
 168                  RQ_USER, "user_name",
 169                  RQ_CLIENT_NAME, "client_hostname",
 170                  RQ_CLIENT_ADDR, "client_addr",
 171                  RQ_FILE, 1,
 172                  0);
 173
 174     /*
 175      * Examine all access-control rules.
 176      */
 177     defl_verdict = PERMIT;
 178     parse_table(hosts_allow_table, &request);
 179     defl_verdict = DENY;
 180     parse_table(hosts_deny_table, &request);
 181     return (0);
 182 }
 183
 184 /* usage - explain */
 185
 186 static void usage()
 187 {
 188     fprintf(stderr, "usage: %s [-a] [-d] [-i inet_conf] [-v]\n", myname);
 189     fprintf(stderr, "   -a: report rules with implicit \"ALLOW\" at end\n");
 190     fprintf(stderr, "   -d: use allow/deny files in current directory\n");
 191     fprintf(stderr, "   -i: location of inetd.conf file\n");
 192     fprintf(stderr, "   -v: list all rules\n");
 193     exit(1);
 194 }
 195
 196 /* parse_table - like table_match(), but examines _all_ entries */
 197
 198 static void parse_table(table, request)
 199 char   *table;
 200 struct request_info *request;
 201 {
 202     FILE   *fp;
 203     int     real_verdict;
 204     char    sv_list[BUFLEN];            /* becomes list of daemons */
 205     char   *cl_list;                    /* becomes list of requests */
 206     char   *sh_cmd;                     /* becomes optional shell command */
 207     char    buf[BUFSIZ];
 208     int     verdict;
 209     struct tcpd_context saved_context;
 210
 211     saved_context = tcpd_context;               /* stupid compilers */
 212
 213     if (fp = fopen(table, "r")) {
 214         tcpd_context.file = table;
 215         tcpd_context.line = 0;
 216         while (xgets(sv_list, sizeof(sv_list), fp)) {
 217             if (sv_list[strlen(sv_list) - 1] != '\n') {
 218                 tcpd_warn("missing newline or line too long");
 219                 continue;
 220             }
 221             if (sv_list[0] == '#' || sv_list[strspn(sv_list, " \t\r\n")] == 0)
 222                 continue;
 223             if ((cl_list = split_at(sv_list, ':')) == 0) {
 224                 tcpd_warn("missing \":\" separator");
 225                 continue;
 226             }
 227             sh_cmd = split_at(cl_list, ':');
 228
 229             if (hosts_access_verbose)
 230                 printf("\n>>> Rule %s line %d:\n",
 231                        tcpd_context.file, tcpd_context.line);
 232
 233             if (hosts_access_verbose)
 234                 print_list("daemons:  ", sv_list);
 235             check_daemon_list(sv_list);
 236
 237             if (hosts_access_verbose)
 238                 print_list("clients:  ", cl_list);
 239             check_client_list(cl_list);
 240
 241 #ifdef PROCESS_OPTIONS
 242             real_verdict = defl_verdict;
 243             if (sh_cmd) {
 244                 verdict = setjmp(tcpd_buf);
 245                 if (verdict != 0) {
 246                     real_verdict = (verdict == AC_PERMIT);
 247                 } else {
 248                     dry_run = 1;
 249                     process_options(sh_cmd, request);
 250                     if (dry_run == 1 && real_verdict && allow_check)
 251                         tcpd_warn("implicit \"allow\" at end of rule");
 252                 }
 253             } else if (defl_verdict && allow_check) {
 254                 tcpd_warn("implicit \"allow\" at end of rule");
 255             }
 256             if (hosts_access_verbose)
 257                 printf("access:   %s\n", real_verdict ? "granted" : "denied");
 258 #else
 259             if (sh_cmd)
 260                 shell_cmd(percent_x(buf, sizeof(buf), sh_cmd, request));
 261             if (hosts_access_verbose)
 262                 printf("access:   %s\n", defl_verdict ? "granted" : "denied");
 263 #endif
 264         }
 265         (void) fclose(fp);
 266     } else if (errno != ENOENT) {
 267         tcpd_warn("cannot open %s: %m", table);
 268     }
 269     tcpd_context = saved_context;
 270 }
 271
 272 /* print_list - pretty-print a list */
 273
 274 static void print_list(title, list)
 275 char   *title;
 276 char   *list;
 277 {
 278     char    buf[BUFLEN];
 279     char   *cp;
 280     char   *next;
 281
 282     fputs(title, stdout);
 283     strcpy(buf, list);
 284
 285     for (cp = strtok(buf, sep); cp != 0; cp = next) {
 286         fputs(cp, stdout);
 287         next = strtok((char *) 0, sep);
 288         if (next != 0)
 289             fputs(" ", stdout);
 290     }
 291     fputs("\n", stdout);
 292 }
 293
 294 /* check_daemon_list - criticize daemon list */
 295
 296 static void check_daemon_list(list)
 297 char   *list;
 298 {
 299     char    buf[BUFLEN];
 300     char   *cp;
 301     char   *host;
 302     int     daemons = 0;
 303
 304     strcpy(buf, list);
 305
 306     for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
 307         if (STR_EQ(cp, "EXCEPT")) {
 308             daemons = 0;
 309         } else {
 310             daemons++;
 311             if ((host = split_at(cp + 1, '@')) != 0 && check_host(host) > 1) {
 312                 tcpd_warn("host %s has more than one address", host);
 313                 tcpd_warn("(consider using an address instead)");
 314             }
 315             check_daemon(cp);
 316         }
 317     }
 318     if (daemons == 0)
 319         tcpd_warn("daemon list is empty or ends in EXCEPT");
 320 }
 321
 322 /* check_client_list - criticize client list */
 323
 324 static void check_client_list(list)
 325 char   *list;
 326 {
 327     char    buf[BUFLEN];
 328     char   *cp;
 329     char   *host;
 330     int     clients = 0;
 331
 332     strcpy(buf, list);
 333
 334     for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
 335         if (STR_EQ(cp, "EXCEPT")) {
 336             clients = 0;
 337         } else {
 338             clients++;
 339             if (host = split_at(cp + 1, '@')) { /* user@host */
 340                 check_user(cp);
 341                 check_host(host);
 342             } else {
 343                 check_host(cp);
 344             }
 345         }
 346     }
 347     if (clients == 0)
 348         tcpd_warn("client list is empty or ends in EXCEPT");
 349 }
 350
 351 /* check_daemon - criticize daemon pattern */
 352
 353 static void check_daemon(pat)
 354 char   *pat;
 355 {
 356     if (pat[0] == '@') {
 357         tcpd_warn("%s: daemon name begins with \"@\"", pat);
 358     } else if (pat[0] == '/') {
 359         tcpd_warn("%s: daemon name begins with \"/\"", pat);
 360     } else if (pat[0] == '.') {
 361         tcpd_warn("%s: daemon name begins with dot", pat);
 362     } else if (pat[strlen(pat) - 1] == '.') {
 363         tcpd_warn("%s: daemon name ends in dot", pat);
 364     } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)) {
 365          /* void */ ;
 366     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 367         tcpd_warn("FAIL is no longer recognized");
 368         tcpd_warn("(use EXCEPT or DENY instead)");
 369     } else if (reserved_name(pat)) {
 370         tcpd_warn("%s: daemon name may be reserved word", pat);
 371     } else {
 372         switch (inet_get(pat)) {
 373         case WR_UNKNOWN:
 374             tcpd_warn("%s: no such process name in %s", pat, inetcf);
 375             inet_set(pat, WR_YES);              /* shut up next time */
 376             break;
 377         case WR_NOT:
 378             tcpd_warn("%s: service possibly not wrapped", pat);
 379             inet_set(pat, WR_YES);
 380             break;
 381         }
 382     }
 383 }
 384
 385 /* check_user - criticize user pattern */
 386
 387 static void check_user(pat)
 388 char   *pat;
 389 {
 390     if (pat[0] == '@') {                        /* @netgroup */
 391         tcpd_warn("%s: user name begins with \"@\"", pat);
 392     } else if (pat[0] == '/') {
 393         tcpd_warn("%s: user name begins with \"/\"", pat);
 394     } else if (pat[0] == '.') {
 395         tcpd_warn("%s: user name begins with dot", pat);
 396     } else if (pat[strlen(pat) - 1] == '.') {
 397         tcpd_warn("%s: user name ends in dot", pat);
 398     } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)
 399                || STR_EQ(pat, "KNOWN")) {
 400          /* void */ ;
 401     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 402         tcpd_warn("FAIL is no longer recognized");
 403         tcpd_warn("(use EXCEPT or DENY instead)");
 404     } else if (reserved_name(pat)) {
 405         tcpd_warn("%s: user name may be reserved word", pat);
 406     }
 407 }
 408
 409 #ifdef INET6
 410 static int is_inet6_addr(pat)
 411     char *pat;
 412 {
 413     struct addrinfo hints, *res;
 414     int len, ret;
 415     char ch;
 416
 417     if (*pat != '[')
 418         return (0);
 419     len = strlen(pat);
 420     if ((ch = pat[len - 1]) != ']')
 421         return (0);
 422     pat[len - 1] = '\0';
 423     memset(&hints, 0, sizeof(hints));
 424     hints.ai_family = AF_INET6;
 425     hints.ai_socktype = SOCK_STREAM;
 426     hints.ai_flags = AI_PASSIVE | AI_NUMERICHOST;
 427     if ((ret = getaddrinfo(pat + 1, NULL, &hints, &res)) == 0)
 428         freeaddrinfo(res);
 429     pat[len - 1] = ch;
 430     return (ret == 0);
 431 }
 432 #endif
 433
 434 /* check_host - criticize host pattern */
 435
 436 static int check_host(pat)
 437 char   *pat;
 438 {
 439     char    buf[BUFSIZ];
 440     char   *mask;
 441     int     addr_count = 1;
 442     FILE   *fp;
 443     struct tcpd_context saved_context;
 444     char   *cp;
 445     char   *wsp = " \t\r\n";
 446
 447     if (pat[0] == '@') {                        /* @netgroup */
 448 #ifdef NO_NETGRENT
 449         /* SCO has no *netgrent() support */
 450 #else
 451 #ifdef NETGROUP
 452         char   *machinep;
 453         char   *userp;
 454         char   *domainp;
 455
 456         setnetgrent(pat + 1);
 457         if (getnetgrent(&machinep, &userp, &domainp) == 0)
 458             tcpd_warn("%s: unknown or empty netgroup", pat + 1);
 459         endnetgrent();
 460 #else
 461         tcpd_warn("netgroup support disabled");
 462 #endif
 463 #endif
 464     } else if (pat[0] == '/') {                 /* /path/name */
 465         if ((fp = fopen(pat, "r")) != 0) {
 466             saved_context = tcpd_context;
 467             tcpd_context.file = pat;
 468             tcpd_context.line = 0;
 469             while (fgets(buf, sizeof(buf), fp)) {
 470                 tcpd_context.line++;
 471                 for (cp = strtok(buf, wsp); cp; cp = strtok((char *) 0, wsp))
 472                     check_host(cp);
 473             }
 474             tcpd_context = saved_context;
 475             fclose(fp);
 476         } else if (errno != ENOENT) {
 477             tcpd_warn("open %s: %m", pat);
 478         }
 479     } else if (mask = split_at(pat, '/')) {     /* network/netmask */
 480 #ifdef INET6
 481         int mask_len;
 482
 483         if ((dot_quad_addr(pat) == INADDR_NONE
 484             || dot_quad_addr(mask) == INADDR_NONE)
 485             && (!is_inet6_addr(pat)
 486                 || ((mask_len = atoi(mask)) < 0 || mask_len > 128)))
 487 #else
 488         if (dot_quad_addr(pat) == INADDR_NONE
 489             || dot_quad_addr(mask) == INADDR_NONE)
 490 #endif
 491             tcpd_warn("%s/%s: bad net/mask pattern", pat, mask);
 492     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 493         tcpd_warn("FAIL is no longer recognized");
 494         tcpd_warn("(use EXCEPT or DENY instead)");
 495     } else if (reserved_name(pat)) {            /* other reserved */
 496          /* void */ ;
 497 #ifdef INET6
 498     } else if (is_inet6_addr(pat)) { /* IPv6 address */
 499         addr_count = 1;
 500 #endif
 501     } else if (NOT_INADDR(pat)) {               /* internet name */
 502         if (pat[strlen(pat) - 1] == '.') {
 503             tcpd_warn("%s: domain or host name ends in dot", pat);
 504         } else if (pat[0] != '.') {
 505             addr_count = check_dns(pat);
 506         }
 507     } else {                                    /* numeric form */
 508         if (STR_EQ(pat, "0.0.0.0") || STR_EQ(pat, "255.255.255.255")) {
 509             /* void */ ;
 510         } else if (pat[0] == '.') {
 511             tcpd_warn("%s: network number begins with dot", pat);
 512         } else if (pat[strlen(pat) - 1] != '.') {
 513             check_dns(pat);
 514         }
 515     }
 516     return (addr_count);
 517 }
 518
 519 /* reserved_name - determine if name is reserved */
 520
 521 static int reserved_name(pat)
 522 char   *pat;
 523 {
 524     return (STR_EQ(pat, unknown)
 525             || STR_EQ(pat, "KNOWN")
 526             || STR_EQ(pat, paranoid)
 527             || STR_EQ(pat, "ALL")
 528             || STR_EQ(pat, "LOCAL"));
 529 }