usr/src/cmd/tcpd/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
  17 #ifndef lint
  18 static char sccsid[] = "@(#) tcpdchk.c 1.8 97/02/12 02:13:25";
  19 #endif
  20
  21 /* System libraries. */
  22
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <netinet/in.h>
  26 #include <arpa/inet.h>
  27 #include <stdio.h>
  28 #include <syslog.h>
  29 #include <setjmp.h>
  30 #include <errno.h>
  31 #include <netdb.h>
  32 #include <string.h>
  33
  34 extern int errno;
  35 extern void exit();
  36 extern int optind;
  37 extern char *optarg;
  38
  39 #ifndef INADDR_NONE
  40 #define INADDR_NONE     (-1)            /* XXX should be 0xffffffff */
  41 #endif
  42
  43 #ifndef S_ISDIR
  44 #define S_ISDIR(m)      (((m) & S_IFMT) == S_IFDIR)
  45 #endif
  46
  47 /* Application-specific. */
  48
  49 #include "tcpd.h"
  50 #include "inetcf.h"
  51 #include "scaffold.h"
  52
  53  /*
  54   * Stolen from hosts_access.c...
  55   */
  56 static char sep[] = ", \t\n";
  57
  58 #define BUFLEN 2048
  59
  60 int     resident = 0;
  61 int     hosts_access_verbose = 0;
  62 char   *hosts_allow_table = HOSTS_ALLOW;
  63 char   *hosts_deny_table = HOSTS_DENY;
  64 extern jmp_buf tcpd_buf;
  65
  66  /*
  67   * Local stuff.
  68   */
  69 static void usage();
  70 static void parse_table();
  71 static void print_list();
  72 static void check_daemon_list();
  73 static void check_client_list();
  74 static void check_daemon();
  75 static void check_user();
  76 static int check_host();
  77 static int reserved_name();
  78
  79 #define PERMIT  1
  80 #define DENY    0
  81
  82 #define YES     1
  83 #define NO      0
  84
  85 static int defl_verdict;
  86 static char *myname;
  87 static int allow_check;
  88 static char *inetcf;
  89
  90 int     main(argc, argv)
  91 int     argc;
  92 char  **argv;
  93 {
  94     struct request_info request;
  95     struct stat st;
  96     int     c;
  97
  98     myname = argv[0];
  99
 100     /*
 101      * Parse the JCL.
 102      */
 103     while ((c = getopt(argc, argv, "adi:v")) != EOF) {
 104         switch (c) {
 105         case 'a':
 106             allow_check = 1;
 107             break;
 108         case 'd':
 109             hosts_allow_table = "hosts.allow";
 110             hosts_deny_table = "hosts.deny";
 111             break;
 112         case 'i':
 113             inetcf = optarg;
 114             break;
 115         case 'v':
 116             hosts_access_verbose++;
 117             break;
 118         default:
 119             usage();
 120             /* NOTREACHED */
 121         }
 122     }
 123     if (argc != optind)
 124         usage();
 125
 126     /*
 127      * When confusion really strikes...
 128      */
 129     if (check_path(REAL_DAEMON_DIR, &st) < 0) {
 130         tcpd_warn("REAL_DAEMON_DIR %s: %m", REAL_DAEMON_DIR);
 131     } else if (!S_ISDIR(st.st_mode)) {
 132         tcpd_warn("REAL_DAEMON_DIR %s is not a directory", REAL_DAEMON_DIR);
 133     }
 134
 135     /*
 136      * Process the inet configuration file (or its moral equivalent). This
 137      * information is used later to find references in hosts.allow/deny to
 138      * unwrapped services, and other possible problems.
 139      */
 140     inetcf = inet_cfg(inetcf);
 141     if (hosts_access_verbose)
 142         printf("Using network configuration file: %s\n", inetcf);
 143
 144     /*
 145      * These are not run from inetd but may have built-in access control.
 146      */
 147     inet_set("portmap", WR_NOT);
 148     inet_set("rpcbind", WR_NOT);
 149
 150     /*
 151      * Check accessibility of access control files.
 152      */
 153     (void) check_path(hosts_allow_table, &st);
 154     (void) check_path(hosts_deny_table, &st);
 155
 156     /*
 157      * Fake up an arbitrary service request.
 158      */
 159     request_init(&request,
 160                  RQ_DAEMON, "daemon_name",
 161                  RQ_SERVER_NAME, "server_hostname",
 162                  RQ_SERVER_ADDR, "server_addr",
 163                  RQ_USER, "user_name",
 164                  RQ_CLIENT_NAME, "client_hostname",
 165                  RQ_CLIENT_ADDR, "client_addr",
 166                  RQ_FILE, 1,
 167                  0);
 168
 169     /*
 170      * Examine all access-control rules.
 171      */
 172     defl_verdict = PERMIT;
 173     parse_table(hosts_allow_table, &request);
 174     defl_verdict = DENY;
 175     parse_table(hosts_deny_table, &request);
 176     return (0);
 177 }
 178
 179 /* usage - explain */
 180
 181 static void usage()
 182 {
 183     fprintf(stderr, "usage: %s [-a] [-d] [-i inet_conf] [-v]\n", myname);
 184     fprintf(stderr, "   -a: report rules with implicit \"ALLOW\" at end\n");
 185     fprintf(stderr, "   -d: use allow/deny files in current directory\n");
 186     fprintf(stderr, "   -i: location of inetd.conf file\n");
 187     fprintf(stderr, "   -v: list all rules\n");
 188     exit(1);
 189 }
 190
 191 /* parse_table - like table_match(), but examines _all_ entries */
 192
 193 static void parse_table(table, request)
 194 char   *table;
 195 struct request_info *request;
 196 {
 197     FILE   *fp;
 198     int     real_verdict;
 199     char    sv_list[BUFLEN];            /* becomes list of daemons */
 200     char   *cl_list;                    /* becomes list of requests */
 201     char   *sh_cmd;                     /* becomes optional shell command */
 202     char    buf[BUFSIZ];
 203     int     verdict;
 204     struct tcpd_context saved_context;
 205
 206     saved_context = tcpd_context;               /* stupid compilers */
 207
 208     if (fp = fopen(table, "r")) {
 209         tcpd_context.file = table;
 210         tcpd_context.line = 0;
 211         while (xgets(sv_list, sizeof(sv_list), fp)) {
 212             if (sv_list[strlen(sv_list) - 1] != '\n') {
 213                 tcpd_warn("missing newline or line too long");
 214                 continue;
 215             }
 216             if (sv_list[0] == '#' || sv_list[strspn(sv_list, " \t\r\n")] == 0)
 217                 continue;
 218             if ((cl_list = split_at(skip_ipv6_addrs(sv_list), ':')) == 0) {
 219                 tcpd_warn("missing \":\" separator");
 220                 continue;
 221             }
 222             sh_cmd = split_at(skip_ipv6_addrs(cl_list), ':');
 223
 224             if (hosts_access_verbose)
 225                 printf("\n>>> Rule %s line %d:\n",
 226                        tcpd_context.file, tcpd_context.line);
 227
 228             if (hosts_access_verbose)
 229                 print_list("daemons:  ", sv_list);
 230             check_daemon_list(sv_list);
 231
 232             if (hosts_access_verbose)
 233                 print_list("clients:  ", cl_list);
 234             check_client_list(cl_list);
 235
 236 #ifdef PROCESS_OPTIONS
 237             real_verdict = defl_verdict;
 238             if (sh_cmd) {
 239                 verdict = setjmp(tcpd_buf);
 240                 if (verdict != 0) {
 241                     real_verdict = (verdict == AC_PERMIT);
 242                 } else {
 243                     dry_run = 1;
 244                     process_options(sh_cmd, request);
 245                     if (dry_run == 1 && real_verdict && allow_check)
 246                         tcpd_warn("implicit \"allow\" at end of rule");
 247                 }
 248             } else if (defl_verdict && allow_check) {
 249                 tcpd_warn("implicit \"allow\" at end of rule");
 250             }
 251             if (hosts_access_verbose)
 252                 printf("access:   %s\n", real_verdict ? "granted" : "denied");
 253 #else
 254             if (sh_cmd)
 255                 shell_cmd(percent_x(buf, sizeof(buf), sh_cmd, request));
 256             if (hosts_access_verbose)
 257                 printf("access:   %s\n", defl_verdict ? "granted" : "denied");
 258 #endif
 259         }
 260         (void) fclose(fp);
 261     } else if (errno != ENOENT) {
 262         tcpd_warn("cannot open %s: %m", table);
 263     }
 264     tcpd_context = saved_context;
 265 }
 266
 267 /* print_list - pretty-print a list */
 268
 269 static void print_list(title, list)
 270 char   *title;
 271 char   *list;
 272 {
 273     char    buf[BUFLEN];
 274     char   *cp;
 275     char   *next;
 276
 277     fputs(title, stdout);
 278     strcpy(buf, list);
 279
 280     for (cp = strtok(buf, sep); cp != 0; cp = next) {
 281         fputs(cp, stdout);
 282         next = strtok((char *) 0, sep);
 283         if (next != 0)
 284             fputs(" ", stdout);
 285     }
 286     fputs("\n", stdout);
 287 }
 288
 289 /* check_daemon_list - criticize daemon list */
 290
 291 static void check_daemon_list(list)
 292 char   *list;
 293 {
 294     char    buf[BUFLEN];
 295     char   *cp;
 296     char   *host;
 297     int     daemons = 0;
 298
 299     strcpy(buf, list);
 300
 301     for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
 302         if (STR_EQ(cp, "EXCEPT")) {
 303             daemons = 0;
 304         } else {
 305             daemons++;
 306             if ((host = split_at(cp + 1, '@')) != 0 && check_host(host) > 1) {
 307                 tcpd_warn("host %s has more than one address", host);
 308                 tcpd_warn("(consider using an address instead)");
 309             }
 310             check_daemon(cp);
 311         }
 312     }
 313     if (daemons == 0)
 314         tcpd_warn("daemon list is empty or ends in EXCEPT");
 315 }
 316
 317 /* check_client_list - criticize client list */
 318
 319 static void check_client_list(list)
 320 char   *list;
 321 {
 322     char    buf[BUFLEN];
 323     char   *cp;
 324     char   *host;
 325     int     clients = 0;
 326
 327     strcpy(buf, list);
 328
 329     for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
 330         if (STR_EQ(cp, "EXCEPT")) {
 331             clients = 0;
 332         } else {
 333             clients++;
 334             if (host = split_at(cp + 1, '@')) { /* user@host */
 335                 check_user(cp);
 336                 check_host(host);
 337             } else {
 338                 check_host(cp);
 339             }
 340         }
 341     }
 342     if (clients == 0)
 343         tcpd_warn("client list is empty or ends in EXCEPT");
 344 }
 345
 346 /* check_daemon - criticize daemon pattern */
 347
 348 static void check_daemon(pat)
 349 char   *pat;
 350 {
 351     if (pat[0] == '@') {
 352         tcpd_warn("%s: daemon name begins with \"@\"", pat);
 353     } else if (pat[0] == '.') {
 354         tcpd_warn("%s: daemon name begins with dot", pat);
 355     } else if (pat[strlen(pat) - 1] == '.') {
 356         tcpd_warn("%s: daemon name ends in dot", pat);
 357     } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)) {
 358          /* void */ ;
 359     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 360         tcpd_warn("FAIL is no longer recognized");
 361         tcpd_warn("(use EXCEPT or DENY instead)");
 362     } else if (reserved_name(pat)) {
 363         tcpd_warn("%s: daemon name may be reserved word", pat);
 364     } else {
 365         switch (inet_get(pat)) {
 366         case WR_UNKNOWN:
 367             tcpd_warn("%s: no such process name in %s", pat, inetcf);
 368             inet_set(pat, WR_YES);              /* shut up next time */
 369             break;
 370         case WR_NOT:
 371             tcpd_warn("%s: service possibly not wrapped", pat);
 372             inet_set(pat, WR_YES);
 373             break;
 374         }
 375     }
 376 }
 377
 378 /* check_user - criticize user pattern */
 379
 380 static void check_user(pat)
 381 char   *pat;
 382 {
 383     if (pat[0] == '@') {                        /* @netgroup */
 384         tcpd_warn("%s: user name begins with \"@\"", pat);
 385     } else if (pat[0] == '.') {
 386         tcpd_warn("%s: user name begins with dot", pat);
 387     } else if (pat[strlen(pat) - 1] == '.') {
 388         tcpd_warn("%s: user name ends in dot", pat);
 389     } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)
 390                || STR_EQ(pat, "KNOWN")) {
 391          /* void */ ;
 392     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 393         tcpd_warn("FAIL is no longer recognized");
 394         tcpd_warn("(use EXCEPT or DENY instead)");
 395     } else if (reserved_name(pat)) {
 396         tcpd_warn("%s: user name may be reserved word", pat);
 397     }
 398 }
 399
 400 /* check_host - criticize host pattern */
 401
 402 static int check_host(pat)
 403 char   *pat;
 404 {
 405     char   *mask;
 406     int     addr_count = 1;
 407
 408     if (pat[0] == '@') {                        /* @netgroup */
 409 #ifdef NO_NETGRENT
 410         /* SCO has no *netgrent() support */
 411 #else
 412 #ifdef NETGROUP
 413         char   *machinep;
 414         char   *userp;
 415         char   *domainp;
 416
 417         setnetgrent(pat + 1);
 418         if (getnetgrent(&machinep, &userp, &domainp) == 0)
 419             tcpd_warn("%s: unknown or empty netgroup", pat + 1);
 420         endnetgrent();
 421 #else
 422         tcpd_warn("netgroup support disabled");
 423 #endif
 424 #endif
 425 #ifdef HAVE_IPV6
 426     } else if (pat[0] == '[') {
 427             struct in6_addr in6;
 428             char *cbr = strchr(pat, ']');
 429             char *slash = strchr(pat, '/');
 430             int err = 0;
 431             int mask = IPV6_ABITS;
 432
 433             if (slash != NULL) {
 434                 *slash = '\0';
 435                 mask = atoi(slash + 1);
 436                 err = mask < 0 || mask > IPV6_ABITS;
 437             }
 438             if (cbr == NULL)
 439                 err = 1;
 440             else {
 441                 *cbr = '\0';
 442                 err += inet_pton(AF_INET6, pat+1, &in6) != 1;
 443             }
 444             if (slash) *slash = '/';
 445             if (cbr) *cbr = ']';
 446             if (err)
 447                 tcpd_warn("bad IP6 address specification: %s", pat);
 448 #endif
 449     } else if (mask = split_at(pat, '/')) {     /* network/netmask */
 450         if (dot_quad_addr(pat) == INADDR_NONE
 451             || dot_quad_addr(mask) == INADDR_NONE)
 452             tcpd_warn("%s/%s: bad net/mask pattern", pat, mask);
 453     } else if (STR_EQ(pat, "FAIL")) {           /* obsolete */
 454         tcpd_warn("FAIL is no longer recognized");
 455         tcpd_warn("(use EXCEPT or DENY instead)");
 456     } else if (reserved_name(pat)) {            /* other reserved */
 457          /* void */ ;
 458     } else if (NOT_INADDR(pat)) {               /* internet name */
 459         if (pat[strlen(pat) - 1] == '.') {
 460             tcpd_warn("%s: domain or host name ends in dot", pat);
 461         } else if (pat[0] != '.') {
 462             addr_count = check_dns(pat);
 463         }
 464     } else {                                    /* numeric form */
 465         if (STR_EQ(pat, "0.0.0.0") || STR_EQ(pat, "255.255.255.255")) {
 466             /* void */ ;
 467         } else if (pat[0] == '.') {
 468             tcpd_warn("%s: network number begins with dot", pat);
 469         } else if (pat[strlen(pat) - 1] != '.') {
 470             check_dns(pat);
 471         }
 472     }
 473     return (addr_count);
 474 }
 475
 476 /* reserved_name - determine if name is reserved */
 477
 478 static int reserved_name(pat)
 479 char   *pat;
 480 {
 481     return (STR_EQ(pat, unknown)
 482             || STR_EQ(pat, "KNOWN")
 483             || STR_EQ(pat, paranoid)
 484             || STR_EQ(pat, "ALL")
 485             || STR_EQ(pat, "LOCAL"));
 486 }