cmd/tcpd/tcpdchk.c

 /*
  * tcpdchk - examine all tcpd access control rules and inetd.conf entries
  *
  * Usage: tcpdchk [-a] [-d] [-i inet_conf] [-v]
  *
  * -a: complain about implicit "allow" at end of rule.
  *
  * -d: rules in current directory.
  *
  * -i: location of inetd.conf file.
  *
  * -v: show all rules.
  *
  * Author: Wietse Venema, Eindhoven University of Technology, The Netherlands.
  */

#ifndef lint
static char sccsid[] = "@(#) tcpdchk.c 1.8 97/02/12 02:13:25";
#endif

/* System libraries. */

#include <sys/types.h>
#include <sys/stat.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <syslog.h>
#include <setjmp.h>
#include <errno.h>
#include <netdb.h>
#include <string.h>

extern int errno;
extern void exit();
extern int optind;
extern char *optarg;

#ifndef INADDR_NONE
#define INADDR_NONE     (-1)        /* XXX should be 0xffffffff */
#endif

#ifndef S_ISDIR
#define S_ISDIR(m)  (((m) & S_IFMT) == S_IFDIR)
#endif

/* Application-specific. */

#include "tcpd.h"
#include "inetcf.h"
#include "scaffold.h"

 /*
  * Stolen from hosts_access.c...
  */
static char sep[] = ", \t\n";

#define BUFLEN 2048

int     resident = 0;
int     hosts_access_verbose = 0;
char   *hosts_allow_table = HOSTS_ALLOW;
char   *hosts_deny_table = HOSTS_DENY;
extern jmp_buf tcpd_buf;

 /*
  * Local stuff.
  */
static void usage();
static void parse_table();
static void print_list();
static void check_daemon_list();
static void check_client_list();
static void check_daemon();
static void check_user();
static int check_host();
static int reserved_name();

#define PERMIT  1
#define DENY    0

#define YES 1
#define NO  0

static int defl_verdict;
static char *myname;
static int allow_check;
static char *inetcf;

int     main(argc, argv)
int     argc;
char  **argv;
{
    struct request_info request;
    struct stat st;
    int     c;

    myname = argv[0];

    /*
     * Parse the JCL.
     */
    while ((c = getopt(argc, argv, "adi:v")) != EOF) {
    switch (c) {
    case 'a':
        allow_check = 1;
        break;
    case 'd':
        hosts_allow_table = "hosts.allow";
        hosts_deny_table = "hosts.deny";
        break;
    case 'i':
        inetcf = optarg;
        break;
    case 'v':
        hosts_access_verbose++;
        break;
    default:
        usage();
        /* NOTREACHED */
    }
    }
    if (argc != optind)
    usage();

    /*
     * When confusion really strikes...
     */
    if (check_path(REAL_DAEMON_DIR, &st) < 0) {
    tcpd_warn("REAL_DAEMON_DIR %s: %m", REAL_DAEMON_DIR);
    } else if (!S_ISDIR(st.st_mode)) {
    tcpd_warn("REAL_DAEMON_DIR %s is not a directory", REAL_DAEMON_DIR);
    }

    /*
     * Process the inet configuration file (or its moral equivalent). This
     * information is used later to find references in hosts.allow/deny to
     * unwrapped services, and other possible problems.
     */
    inetcf = inet_cfg(inetcf);
    if (hosts_access_verbose)
    printf("Using network configuration file: %s\n", inetcf);

    /*
     * These are not run from inetd but may have built-in access control.
     */
    inet_set("portmap", WR_NOT);
    inet_set("rpcbind", WR_NOT);

    /*
     * Check accessibility of access control files.
     */
    (void) check_path(hosts_allow_table, &st);
    (void) check_path(hosts_deny_table, &st);

    /*
     * Fake up an arbitrary service request.
     */
    request_init(&request,
         RQ_DAEMON, "daemon_name",
         RQ_SERVER_NAME, "server_hostname",
         RQ_SERVER_ADDR, "server_addr",
         RQ_USER, "user_name",
         RQ_CLIENT_NAME, "client_hostname",
         RQ_CLIENT_ADDR, "client_addr",
         RQ_FILE, 1,
         0);

    /*
     * Examine all access-control rules.
     */
    defl_verdict = PERMIT;
    parse_table(hosts_allow_table, &request);
    defl_verdict = DENY;
    parse_table(hosts_deny_table, &request);
    return (0);
}

/* usage - explain */

static void usage()
{
    fprintf(stderr, "usage: %s [-a] [-d] [-i inet_conf] [-v]\n", myname);
    fprintf(stderr, "   -a: report rules with implicit \"ALLOW\" at end\n");
    fprintf(stderr, "   -d: use allow/deny files in current directory\n");
    fprintf(stderr, "   -i: location of inetd.conf file\n");
    fprintf(stderr, "   -v: list all rules\n");
    exit(1);
}

/* parse_table - like table_match(), but examines _all_ entries */

static void parse_table(table, request)
char   *table;
struct request_info *request;
{
    FILE   *fp;
    int     real_verdict;
    char    sv_list[BUFLEN];        /* becomes list of daemons */
    char   *cl_list;            /* becomes list of requests */
    char   *sh_cmd;         /* becomes optional shell command */
    char    buf[BUFSIZ];
    int     verdict;
    struct tcpd_context saved_context;

    saved_context = tcpd_context;       /* stupid compilers */

    if (fp = fopen(table, "r")) {
    tcpd_context.file = table;
    tcpd_context.line = 0;
    while (xgets(sv_list, sizeof(sv_list), fp)) {
        if (sv_list[strlen(sv_list) - 1] != '\n') {
        tcpd_warn("missing newline or line too long");
        continue;
        }
        if (sv_list[0] == '#' || sv_list[strspn(sv_list, " \t\r\n")] == 0)
        continue;
        if ((cl_list = split_at(skip_ipv6_addrs(sv_list), ':')) == 0) {
        tcpd_warn("missing \":\" separator");
        continue;
        }
        sh_cmd = split_at(skip_ipv6_addrs(cl_list), ':');

        if (hosts_access_verbose)
        printf("\n>>> Rule %s line %d:\n",
               tcpd_context.file, tcpd_context.line);

        if (hosts_access_verbose)
        print_list("daemons:  ", sv_list);
        check_daemon_list(sv_list);

        if (hosts_access_verbose)
        print_list("clients:  ", cl_list);
        check_client_list(cl_list);

#ifdef PROCESS_OPTIONS
        real_verdict = defl_verdict;
        if (sh_cmd) {
        verdict = setjmp(tcpd_buf);
        if (verdict != 0) {
            real_verdict = (verdict == AC_PERMIT);
        } else {
            dry_run = 1;
            process_options(sh_cmd, request);
            if (dry_run == 1 && real_verdict && allow_check)
            tcpd_warn("implicit \"allow\" at end of rule");
        }
        } else if (defl_verdict && allow_check) {
        tcpd_warn("implicit \"allow\" at end of rule");
        }
        if (hosts_access_verbose)
        printf("access:   %s\n", real_verdict ? "granted" : "denied");
#else
        if (sh_cmd)
        shell_cmd(percent_x(buf, sizeof(buf), sh_cmd, request));
        if (hosts_access_verbose)
        printf("access:   %s\n", defl_verdict ? "granted" : "denied");
#endif
    }
    (void) fclose(fp);
    } else if (errno != ENOENT) {
    tcpd_warn("cannot open %s: %m", table);
    }
    tcpd_context = saved_context;
}

/* print_list - pretty-print a list */

static void print_list(title, list)
char   *title;
char   *list;
{
    char    buf[BUFLEN];
    char   *cp;
    char   *next;

    fputs(title, stdout);
    strcpy(buf, list);

    for (cp = strtok(buf, sep); cp != 0; cp = next) {
    fputs(cp, stdout);
    next = strtok((char *) 0, sep);
    if (next != 0)
        fputs(" ", stdout);
    }
    fputs("\n", stdout);
}

/* check_daemon_list - criticize daemon list */

static void check_daemon_list(list)
char   *list;
{
    char    buf[BUFLEN];
    char   *cp;
    char   *host;
    int     daemons = 0;

    strcpy(buf, list);

    for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
    if (STR_EQ(cp, "EXCEPT")) {
        daemons = 0;
    } else {
        daemons++;
        if ((host = split_at(cp + 1, '@')) != 0 && check_host(host) > 1) {
        tcpd_warn("host %s has more than one address", host);
        tcpd_warn("(consider using an address instead)");
        }
        check_daemon(cp);
    }
    }
    if (daemons == 0)
    tcpd_warn("daemon list is empty or ends in EXCEPT");
}

/* check_client_list - criticize client list */

static void check_client_list(list)
char   *list;
{
    char    buf[BUFLEN];
    char   *cp;
    char   *host;
    int     clients = 0;

    strcpy(buf, list);

    for (cp = strtok(buf, sep); cp != 0; cp = strtok((char *) 0, sep)) {
    if (STR_EQ(cp, "EXCEPT")) {
        clients = 0;
    } else {
        clients++;
        if (host = split_at(cp + 1, '@')) { /* user@host */
        check_user(cp);
        check_host(host);
        } else {
        check_host(cp);
        }
    }
    }
    if (clients == 0)
    tcpd_warn("client list is empty or ends in EXCEPT");
}

/* check_daemon - criticize daemon pattern */

static void check_daemon(pat)
char   *pat;
{
    if (pat[0] == '@') {
    tcpd_warn("%s: daemon name begins with \"@\"", pat);
    } else if (pat[0] == '.') {
    tcpd_warn("%s: daemon name begins with dot", pat);
    } else if (pat[strlen(pat) - 1] == '.') {
    tcpd_warn("%s: daemon name ends in dot", pat);
    } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)) {
     /* void */ ;
    } else if (STR_EQ(pat, "FAIL")) {       /* obsolete */
    tcpd_warn("FAIL is no longer recognized");
    tcpd_warn("(use EXCEPT or DENY instead)");
    } else if (reserved_name(pat)) {
    tcpd_warn("%s: daemon name may be reserved word", pat);
    } else {
    switch (inet_get(pat)) {
    case WR_UNKNOWN:
        tcpd_warn("%s: no such process name in %s", pat, inetcf);
        inet_set(pat, WR_YES);      /* shut up next time */
        break;
    case WR_NOT:
        tcpd_warn("%s: service possibly not wrapped", pat);
        inet_set(pat, WR_YES);
        break;
    }
    }
}

/* check_user - criticize user pattern */

static void check_user(pat)
char   *pat;
{
    if (pat[0] == '@') {            /* @netgroup */
    tcpd_warn("%s: user name begins with \"@\"", pat);
    } else if (pat[0] == '.') {
    tcpd_warn("%s: user name begins with dot", pat);
    } else if (pat[strlen(pat) - 1] == '.') {
    tcpd_warn("%s: user name ends in dot", pat);
    } else if (STR_EQ(pat, "ALL") || STR_EQ(pat, unknown)
           || STR_EQ(pat, "KNOWN")) {
     /* void */ ;
    } else if (STR_EQ(pat, "FAIL")) {       /* obsolete */
    tcpd_warn("FAIL is no longer recognized");
    tcpd_warn("(use EXCEPT or DENY instead)");
    } else if (reserved_name(pat)) {
    tcpd_warn("%s: user name may be reserved word", pat);
    }
}

/* check_host - criticize host pattern */

static int check_host(pat)
char   *pat;
{
    char   *mask;
    int     addr_count = 1;

    if (pat[0] == '@') {            /* @netgroup */
#ifdef NO_NETGRENT
    /* SCO has no *netgrent() support */
#else
#ifdef NETGROUP
    char   *machinep;
    char   *userp;
    char   *domainp;

    setnetgrent(pat + 1);
    if (getnetgrent(&machinep, &userp, &domainp) == 0)
        tcpd_warn("%s: unknown or empty netgroup", pat + 1);
    endnetgrent();
#else
    tcpd_warn("netgroup support disabled");
#endif
#endif
#ifdef HAVE_IPV6
    } else if (pat[0] == '[') {
        struct in6_addr in6;
        char *cbr = strchr(pat, ']');
        char *slash = strchr(pat, '/');
        int err = 0;
        int mask = IPV6_ABITS;

        if (slash != NULL) {
        *slash = '\0';
        mask = atoi(slash + 1);
        err = mask < 0 || mask > IPV6_ABITS;
        }
        if (cbr == NULL)
        err = 1;
        else {
        *cbr = '\0';
        err += inet_pton(AF_INET6, pat+1, &in6) != 1;
        }
        if (slash) *slash = '/';
        if (cbr) *cbr = ']';
        if (err)
        tcpd_warn("bad IP6 address specification: %s", pat);
#endif
    } else if (mask = split_at(pat, '/')) { /* network/netmask */
    if (dot_quad_addr(pat) == INADDR_NONE
        || dot_quad_addr(mask) == INADDR_NONE)
        tcpd_warn("%s/%s: bad net/mask pattern", pat, mask);
    } else if (STR_EQ(pat, "FAIL")) {       /* obsolete */
    tcpd_warn("FAIL is no longer recognized");
    tcpd_warn("(use EXCEPT or DENY instead)");
    } else if (reserved_name(pat)) {        /* other reserved */
     /* void */ ;
    } else if (NOT_INADDR(pat)) {       /* internet name */
    if (pat[strlen(pat) - 1] == '.') {
        tcpd_warn("%s: domain or host name ends in dot", pat);
    } else if (pat[0] != '.') {
        addr_count = check_dns(pat);
    }
    } else {                    /* numeric form */
    if (STR_EQ(pat, "0.0.0.0") || STR_EQ(pat, "255.255.255.255")) {
        /* void */ ;
    } else if (pat[0] == '.') {
        tcpd_warn("%s: network number begins with dot", pat);
    } else if (pat[strlen(pat) - 1] != '.') {
        check_dns(pat);
    }
    }
    return (addr_count);
}

/* reserved_name - determine if name is reserved */

static int reserved_name(pat)
char   *pat;
{
    return (STR_EQ(pat, unknown)
        || STR_EQ(pat, "KNOWN")
        || STR_EQ(pat, paranoid)
        || STR_EQ(pat, "ALL")
        || STR_EQ(pat, "LOCAL"));
}