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freebsd/contrib/tcp_wrappers/tcpdchk.c
Yoshinobu Inoue 8053080cbc Missing tcp_wrapper IPv6 support seemed to be a bug, so commit it. 
Now when tcp_wrapper is enabled by inetd -wW,
  several accesses which should be permitted are refused only for IPv6,
  if hostname is used to decide the host to be allowed.
  IPv6 users will be just upset.

  About security related concern.
    -All extensions are wrapped by #ifdef INET6, so people can completely
     disable the extension by recompile libwrap without INET6 option.
    -Access via IPv6 is not enabled by default.
     People need to enable IPv6 access by changing /etc/inetd.conf at first,
     by adding tcp6 and/or tcp46 entries.
    -The base of patches are from KAME package and are actually daily used
     for more than a year in several Japanese IPv6 environments.
    -Patches are reviewed by markm.

Approved by: jkh

Submitted by: Hajimu UMEMOTO <ume@mahoroba.org>
Reviewed by: markm
Obtained from: KAME project
2000-02-03 10:27:03 +00:00

525 lines
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/*
* 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.
*
* $FreeBSD$
*/
#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>
#ifdef INET6
#include <sys/socket.h>
#endif
#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(sv_list, ':')) == 0) {
tcpd_warn("missing \":\" separator");
continue;
}
sh_cmd = split_at(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 \"/\"", 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 \"/\"", 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);
}
}
#ifdef INET6
static int is_inet6_addr(pat)
char *pat;
{
struct in6_addr addr;
int len, ret;
char ch;
if (*pat != '[')
return (0);
len = strlen(pat);
if ((ch = pat[len - 1]) != ']')
return (0);
pat[len - 1] = '\0';
ret = inet_pton(AF_INET6, pat + 1, &addr);
pat[len - 1] = ch;
return (ret == 1);
}
#endif
/* check_host - criticize host pattern */
static int check_host(pat)
char *pat;
{
char buf[BUFSIZ];
char *mask;
int addr_count = 1;
FILE *fp;
struct tcpd_context saved_context;
char *cp;
char *wsp = " \t\r\n";
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
} else if (pat[0] == '/') { /* /path/name */
if ((fp = fopen(pat, "r")) != 0) {
saved_context = tcpd_context;
tcpd_context.file = pat;
tcpd_context.line = 0;
while (fgets(buf, sizeof(buf), fp)) {
tcpd_context.line++;
for (cp = strtok(buf, wsp); cp; cp = strtok((char *) 0, wsp))
check_host(cp);
}
tcpd_context = saved_context;
fclose(fp);
} else if (errno != ENOENT) {
tcpd_warn("open %s: %m", pat);
}
} else if (mask = split_at(pat, '/')) { /* network/netmask */
#ifdef INET6
int mask_len;
if ((dot_quad_addr(pat) == INADDR_NONE
|| dot_quad_addr(mask) == INADDR_NONE)
&& (!is_inet6_addr(pat)
|| ((mask_len = atoi(mask)) < 0 || mask_len > 128)))
#else
if (dot_quad_addr(pat) == INADDR_NONE
|| dot_quad_addr(mask) == INADDR_NONE)
#endif
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 */ ;
#ifdef INET6
} else if (is_inet6_addr(pat)) { /* IPv6 address */
addr_count = 1;
#endif
} 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"));
}
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