contrib/tcp_wrappers/inetcf.c

   1 /* $FreeBSD$ */
   2  /*
   3   * Routines to parse an inetd.conf or tlid.conf file. This would be a great
   4   * job for a PERL script.
   5   *
   6   * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
   7   */
   8
   9 #ifndef lint
  10 static char sccsid[] = "@(#) inetcf.c 1.7 97/02/12 02:13:23";
  11 #endif
  12
  13 #include <sys/types.h>
  14 #include <sys/stat.h>
  15 #include <stdio.h>
  16 #include <errno.h>
  17 #include <string.h>
  18
  19 extern int errno;
  20 extern void exit();
  21 extern char *malloc();
  22
  23 #include "tcpd.h"
  24 #include "inetcf.h"
  25
  26  /*
  27   * Network configuration files may live in unusual places. Here are some
  28   * guesses. Shorter names follow longer ones.
  29   */
  30 char   *inet_files[] = {
  31     "/private/etc/inetd.conf",          /* NEXT */
  32     "/etc/inet/inetd.conf",             /* SYSV4 */
  33     "/usr/etc/inetd.conf",              /* IRIX?? */
  34     "/etc/inetd.conf",                  /* BSD */
  35     "/etc/net/tlid.conf",               /* SYSV4?? */
  36     "/etc/saf/tlid.conf",               /* SYSV4?? */
  37     "/etc/tlid.conf",                   /* SYSV4?? */
  38     0,
  39 };
  40
  41 static void inet_chk();
  42 static char *base_name();
  43
  44  /*
  45   * Structure with everything we know about a service.
  46   */
  47 struct inet_ent {
  48     struct inet_ent *next;
  49     int     type;
  50     char    name[1];
  51 };
  52
  53 static struct inet_ent *inet_list = 0;
  54
  55 static char whitespace[] = " \t\r\n";
  56
  57 /* inet_conf - read in and examine inetd.conf (or tlid.conf) entries */
  58
  59 char   *inet_cfg(conf)
  60 char   *conf;
  61 {
  62     char    buf[BUFSIZ];
  63     FILE   *fp;
  64     char   *service;
  65     char   *protocol;
  66     char   *user;
  67     char   *path;
  68     char   *arg0;
  69     char   *arg1;
  70     struct tcpd_context saved_context;
  71     char   *percent_m();
  72     int     i;
  73     struct stat st;
  74
  75     saved_context = tcpd_context;
  76
  77     /*
  78      * The inetd.conf (or tlid.conf) information is so useful that we insist
  79      * on its availability. When no file is given run a series of educated
  80      * guesses.
  81      */
  82     if (conf != 0) {
  83         if ((fp = fopen(conf, "r")) == 0) {
  84             fprintf(stderr, percent_m(buf, "open %s: %m\n"), conf);
  85             exit(1);
  86         }
  87     } else {
  88         for (i = 0; inet_files[i] && (fp = fopen(inet_files[i], "r")) == 0; i++)
  89              /* void */ ;
  90         if (fp == 0) {
  91             fprintf(stderr, "Cannot find your inetd.conf or tlid.conf file.\n");
  92             fprintf(stderr, "Please specify its location.\n");
  93             exit(1);
  94         }
  95         conf = inet_files[i];
  96         check_path(conf, &st);
  97     }
  98
  99     /*
 100      * Process the file. After the 7.0 wrapper release it became clear that
 101      * there are many more inetd.conf formats than the 8 systems that I had
 102      * studied. EP/IX uses a two-line specification for rpc services; HP-UX
 103      * permits long lines to be broken with backslash-newline.
 104      */
 105     tcpd_context.file = conf;
 106     tcpd_context.line = 0;
 107     while (xgets(buf, sizeof(buf), fp)) {
 108         service = strtok(buf, whitespace);      /* service */
 109         if (service == 0 || *service == '#')
 110             continue;
 111         if (STR_NE(service, "stream") && STR_NE(service, "dgram"))
 112             strtok((char *) 0, whitespace);     /* endpoint */
 113         protocol = strtok((char *) 0, whitespace);
 114         (void) strtok((char *) 0, whitespace);  /* wait */
 115         if ((user = strtok((char *) 0, whitespace)) == 0)
 116             continue;
 117         if (user[0] == '/') {                   /* user */
 118             path = user;
 119         } else {                                /* path */
 120             if ((path = strtok((char *) 0, whitespace)) == 0)
 121                 continue;
 122         }
 123         if (path[0] == '?')                     /* IRIX optional service */
 124             path++;
 125         if (STR_EQ(path, "internal"))
 126             continue;
 127         if (path[strspn(path, "-0123456789")] == 0) {
 128
 129             /*
 130              * ConvexOS puts RPC version numbers before path names. Jukka
 131              * Ukkonen <ukkonen@csc.fi>.
 132              */
 133             if ((path = strtok((char *) 0, whitespace)) == 0)
 134                 continue;
 135         }
 136         if ((arg0 = strtok((char *) 0, whitespace)) == 0) {
 137             tcpd_warn("incomplete line");
 138             continue;
 139         }
 140         if (arg0[strspn(arg0, "0123456789")] == 0) {
 141
 142             /*
 143              * We're reading a tlid.conf file, the format is:
 144              *
 145              * ...stuff... path arg_count arguments mod_count modules
 146              */
 147             if ((arg0 = strtok((char *) 0, whitespace)) == 0) {
 148                 tcpd_warn("incomplete line");
 149                 continue;
 150             }
 151         }
 152         if ((arg1 = strtok((char *) 0, whitespace)) == 0)
 153             arg1 = "";
 154
 155         inet_chk(protocol, path, arg0, arg1);
 156     }
 157     fclose(fp);
 158     tcpd_context = saved_context;
 159     return (conf);
 160 }
 161
 162 /* inet_chk - examine one inetd.conf (tlid.conf?) entry */
 163
 164 static void inet_chk(protocol, path, arg0, arg1)
 165 char   *protocol;
 166 char   *path;
 167 char   *arg0;
 168 char   *arg1;
 169 {
 170     char    daemon[BUFSIZ];
 171     struct stat st;
 172     int     wrap_status = WR_MAYBE;
 173     char   *base_name_path = base_name(path);
 174     char   *tcpd_proc_name = (arg0[0] == '/' ? base_name(arg0) : arg0);
 175
 176     /*
 177      * Always warn when the executable does not exist or when it is not
 178      * executable.
 179      */
 180     if (check_path(path, &st) < 0) {
 181         tcpd_warn("%s: not found: %m", path);
 182     } else if ((st.st_mode & 0100) == 0) {
 183         tcpd_warn("%s: not executable", path);
 184     }
 185
 186     /*
 187      * Cheat on the miscd tests, nobody uses it anymore.
 188      */
 189     if (STR_EQ(base_name_path, "miscd")) {
 190         inet_set(arg0, WR_YES);
 191         return;
 192     }
 193
 194     /*
 195      * While we are here...
 196      */
 197     if (STR_EQ(tcpd_proc_name, "rexd") || STR_EQ(tcpd_proc_name, "rpc.rexd"))
 198         tcpd_warn("%s may be an insecure service", tcpd_proc_name);
 199
 200     /*
 201      * The tcpd program gets most of the attention.
 202      */
 203     if (STR_EQ(base_name_path, "tcpd")) {
 204
 205         if (STR_EQ(tcpd_proc_name, "tcpd"))
 206             tcpd_warn("%s is recursively calling itself", tcpd_proc_name);
 207
 208         wrap_status = WR_YES;
 209
 210         /*
 211          * Check: some sites install the wrapper set-uid.
 212          */
 213         if ((st.st_mode & 06000) != 0)
 214             tcpd_warn("%s: file is set-uid or set-gid", path);
 215
 216         /*
 217          * Check: some sites insert tcpd in inetd.conf, instead of replacing
 218          * the daemon pathname.
 219          */
 220         if (arg0[0] == '/' && STR_EQ(tcpd_proc_name, base_name(arg1)))
 221             tcpd_warn("%s inserted before %s", path, arg0);
 222
 223         /*
 224          * Check: make sure files exist and are executable. On some systems
 225          * the network daemons are set-uid so we cannot complain. Note that
 226          * tcpd takes the basename only in case of absolute pathnames.
 227          */
 228         if (arg0[0] == '/') {                   /* absolute path */
 229             if (check_path(arg0, &st) < 0) {
 230                 tcpd_warn("%s: not found: %m", arg0);
 231             } else if ((st.st_mode & 0100) == 0) {
 232                 tcpd_warn("%s: not executable", arg0);
 233             }
 234         } else {                                /* look in REAL_DAEMON_DIR */
 235             sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0);
 236             if (check_path(daemon, &st) < 0) {
 237                 tcpd_warn("%s: not found in %s: %m",
 238                           arg0, REAL_DAEMON_DIR);
 239             } else if ((st.st_mode & 0100) == 0) {
 240                 tcpd_warn("%s: not executable", daemon);
 241             }
 242         }
 243
 244     } else {
 245
 246         /*
 247          * No tcpd program found. Perhaps they used the "simple installation"
 248          * recipe. Look for a file with the same basename in REAL_DAEMON_DIR.
 249          * Draw some conservative conclusions when a distinct file is found.
 250          */
 251         sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0);
 252         if (STR_EQ(path, daemon)) {
 253 #ifdef __FreeBSD__
 254             wrap_status = WR_MAYBE;
 255 #else
 256             wrap_status = WR_NOT;
 257 #endif
 258         } else if (check_path(daemon, &st) >= 0) {
 259             wrap_status = WR_MAYBE;
 260         } else if (errno == ENOENT) {
 261             wrap_status = WR_NOT;
 262         } else {
 263             tcpd_warn("%s: file lookup: %m", daemon);
 264             wrap_status = WR_MAYBE;
 265         }
 266     }
 267
 268     /*
 269      * Alas, we cannot wrap rpc/tcp services.
 270      */
 271     if (wrap_status == WR_YES && STR_EQ(protocol, "rpc/tcp"))
 272         tcpd_warn("%s: cannot wrap rpc/tcp services", tcpd_proc_name);
 273
 274     inet_set(tcpd_proc_name, wrap_status);
 275 }
 276
 277 /* inet_set - remember service status */
 278
 279 void    inet_set(name, type)
 280 char   *name;
 281 int     type;
 282 {
 283     struct inet_ent *ip =
 284     (struct inet_ent *) malloc(sizeof(struct inet_ent) + strlen(name));
 285
 286     if (ip == 0) {
 287         fprintf(stderr, "out of memory\n");
 288         exit(1);
 289     }
 290     ip->next = inet_list;
 291     strcpy(ip->name, name);
 292     ip->type = type;
 293     inet_list = ip;
 294 }
 295
 296 /* inet_get - look up service status */
 297
 298 int     inet_get(name)
 299 char   *name;
 300 {
 301     struct inet_ent *ip;
 302
 303     if (inet_list == 0)
 304         return (WR_MAYBE);
 305
 306     for (ip = inet_list; ip; ip = ip->next)
 307         if (STR_EQ(ip->name, name))
 308             return (ip->type);
 309
 310     return (-1);
 311 }
 312
 313 /* base_name - compute last pathname component */
 314
 315 static char *base_name(path)
 316 char   *path;
 317 {
 318     char   *cp;
 319
 320     if ((cp = strrchr(path, '/')) != 0)
 321         path = cp + 1;
 322     return (path);
 323 }