/* * Routines to parse an inetd.conf or tlid.conf file. This would be a great * job for a PERL script. * * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands. */ #ifndef lint static char sccsid[] = "@(#) inetcf.c 1.6 96/02/11 17:01:29"; #endif #include #include #include #include #include extern int errno; extern void exit(); #include "tcpd.h" #include "inetcf.h" /* * Programs that use libwrap directly are not in inetd.conf, and so must * be added here in a similar format. (We pretend we found them in * /etc/inetd.conf.) Each one is a set of three strings that correspond * to fields in /etc/inetd.conf: * protocol (field 3), path (field 6), arg0 (field 7) * The last entry should be a NULL. */ char *uses_libwrap[] = { "tcp", "/usr/sbin/sendmail", "sendmail", (char *) NULL }; /* * Network configuration files may live in unusual places. Here are some * guesses. Shorter names follow longer ones. */ char *inet_files[] = { "/private/etc/inetd.conf", /* NEXT */ "/etc/inet/inetd.conf", /* SYSV4 */ "/usr/etc/inetd.conf", /* IRIX?? */ "/etc/inetd.conf", /* BSD */ "/etc/net/tlid.conf", /* SYSV4?? */ "/etc/saf/tlid.conf", /* SYSV4?? */ "/etc/tlid.conf", /* SYSV4?? */ 0, }; static void inet_chk(); static char *base_name(); /* * Structure with everything we know about a service. */ struct inet_ent { struct inet_ent *next; int type; char name[1]; }; static struct inet_ent *inet_list = 0; static char whitespace[] = " \t\r\n"; /* inet_conf - read in and examine inetd.conf (or tlid.conf) entries */ char *inet_cfg(conf) char *conf; { char buf[BUFSIZ]; FILE *fp; char **wrapped; char *service; char *protocol; char *user; char *path; char *arg0; char *arg1; struct tcpd_context saved_context; char *percent_m(); int i; struct stat st; saved_context = tcpd_context; /* * The inetd.conf (or tlid.conf) information is so useful that we insist * on its availability. When no file is given run a series of educated * guesses. */ if (conf != 0) { if ((fp = fopen(conf, "r")) == 0) { fprintf(stderr, percent_m(buf, "open %s: %m\n"), conf); exit(1); } } else { for (i = 0; inet_files[i] && (fp = fopen(inet_files[i], "r")) == 0; i++) /* void */ ; if (fp == 0) { fprintf(stderr, "Cannot find your inetd.conf or tlid.conf file.\n"); fprintf(stderr, "Please specify its location.\n"); exit(1); } conf = inet_files[i]; check_path(conf, &st); } /* * Process the list of programs that use libwrap directly. */ wrapped = uses_libwrap; while (*wrapped != NULL) { inet_chk(wrapped[0], wrapped[1], wrapped[2], ""); wrapped += 3; } /* * Process the file. After the 7.0 wrapper release it became clear that * there are many more inetd.conf formats than the 8 systems that I had * studied. EP/IX uses a two-line specification for rpc services; HP-UX * permits long lines to be broken with backslash-newline. */ tcpd_context.file = conf; tcpd_context.line = 0; while (xgets(buf, sizeof(buf), fp)) { service = strtok(buf, whitespace); /* service */ if (service == 0 || *service == '#') continue; if (STR_NE(service, "stream") && STR_NE(service, "dgram")) strtok((char *) 0, whitespace); /* endpoint */ protocol = strtok((char *) 0, whitespace); (void) strtok((char *) 0, whitespace); /* wait */ if ((user = strtok((char *) 0, whitespace)) == 0) continue; if (user[0] == '/') { /* user */ path = user; } else { /* path */ if ((path = strtok((char *) 0, whitespace)) == 0) continue; } if (STR_EQ(path, "internal")) continue; if (path[strspn(path, "-0123456789")] == 0) { /* * ConvexOS puts RPC version numbers before path names. Jukka * Ukkonen . */ if ((path = strtok((char *) 0, whitespace)) == 0) continue; } if ((arg0 = strtok((char *) 0, whitespace)) == 0) { tcpd_warn("incomplete line"); continue; } if (arg0[strspn(arg0, "0123456789")] == 0) { /* * We're reading a tlid.conf file, the format is: * * ...stuff... path arg_count arguments mod_count modules */ if ((arg0 = strtok((char *) 0, whitespace)) == 0) { tcpd_warn("incomplete line"); continue; } } if ((arg1 = strtok((char *) 0, whitespace)) == 0) arg1 = ""; inet_chk(protocol, path, arg0, arg1); } fclose(fp); tcpd_context = saved_context; return (conf); } /* inet_chk - examine one inetd.conf (tlid.conf?) entry */ static void inet_chk(protocol, path, arg0, arg1) char *protocol; char *path; char *arg0; char *arg1; { char daemon[BUFSIZ]; struct stat st; int wrap_status = WR_MAYBE; char *base_name_path = base_name(path); char *tcpd_proc_name = (arg0[0] == '/' ? base_name(arg0) : arg0); /* * Always warn when the executable does not exist or when it is not * executable. */ if (check_path(path, &st) < 0) { tcpd_warn("%s: not found: %m", path); } else if ((st.st_mode & 0100) == 0) { tcpd_warn("%s: not executable", path); } /* * Cheat on the miscd tests, nobody uses it anymore. */ if (STR_EQ(base_name_path, "miscd")) { inet_set(arg0, WR_YES); return; } /* * While we are here... */ if (STR_EQ(tcpd_proc_name, "rexd") || STR_EQ(tcpd_proc_name, "rpc.rexd")) tcpd_warn("%s may be an insecure service", tcpd_proc_name); /* * The tcpd program gets most of the attention. */ if (STR_EQ(base_name_path, "tcpd")) { if (STR_EQ(tcpd_proc_name, "tcpd")) tcpd_warn("%s is recursively calling itself", tcpd_proc_name); wrap_status = WR_YES; /* * Check: some sites install the wrapper set-uid. */ if ((st.st_mode & 06000) != 0) tcpd_warn("%s: file is set-uid or set-gid", path); /* * Check: some sites insert tcpd in inetd.conf, instead of replacing * the daemon pathname. */ if (arg0[0] == '/' && STR_EQ(tcpd_proc_name, base_name(arg1))) tcpd_warn("%s inserted before %s", path, arg0); /* * Check: make sure files exist and are executable. On some systems * the network daemons are set-uid so we cannot complain. Note that * tcpd takes the basename only in case of absolute pathnames. */ if (arg0[0] == '/') { /* absolute path */ if (check_path(arg0, &st) < 0) { tcpd_warn("%s: not found: %m", arg0); } else if ((st.st_mode & 0100) == 0) { tcpd_warn("%s: not executable", arg0); } } else { /* look in REAL_DAEMON_DIR */ sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0); if (check_path(daemon, &st) < 0) { tcpd_warn("%s: not found in %s: %m", arg0, REAL_DAEMON_DIR); } else if ((st.st_mode & 0100) == 0) { tcpd_warn("%s: not executable", daemon); } } } else { /* * No tcpd program found. Perhaps they used the "simple installation" * recipe. Look for a file with the same basename in REAL_DAEMON_DIR. * Draw some conservative conclusions when a distinct file is found. */ sprintf(daemon, "%s/%s", REAL_DAEMON_DIR, arg0); if (STR_EQ(path, daemon)) { wrap_status = WR_NOT; } else if (check_path(daemon, &st) >= 0) { wrap_status = WR_MAYBE; } else if (errno == ENOENT) { wrap_status = WR_NOT; } else { tcpd_warn("%s: file lookup: %m", daemon); wrap_status = WR_MAYBE; } } /* * Alas, we cannot wrap rpc/tcp services. */ if (wrap_status == WR_YES && STR_EQ(protocol, "rpc/tcp")) tcpd_warn("%s: cannot wrap rpc/tcp services", tcpd_proc_name); /* NetBSD inetd wraps all programs */ if (! STR_EQ(protocol, "rpc/tcp")) wrap_status = WR_YES; inet_set(tcpd_proc_name, wrap_status); } /* inet_set - remember service status */ void inet_set(name, type) char *name; int type; { struct inet_ent *ip = (struct inet_ent *) malloc(sizeof(struct inet_ent) + strlen(name)); if (ip == 0) { fprintf(stderr, "out of memory\n"); exit(1); } ip->next = inet_list; strcpy(ip->name, name); ip->type = type; inet_list = ip; } /* inet_get - look up service status */ int inet_get(name) char *name; { struct inet_ent *ip; if (inet_list == 0) return (WR_MAYBE); for (ip = inet_list; ip; ip = ip->next) if (STR_EQ(ip->name, name)) return (ip->type); return (-1); } /* base_name - compute last pathname component */ static char *base_name(path) char *path; { char *cp; if ((cp = strrchr(path, '/')) != 0) path = cp + 1; return (path); }