usr/src/cmd/tcpd/inetcf.c

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