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