1/*
2 * Copyright (c) 1997-2005 Kungliga Tekniska Högskolan
3 * (Royal Institute of Technology, Stockholm, Sweden).
4 * All rights reserved.
5 *
6 * Portions Copyright (c) 2009 Apple Inc. All rights reserved.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 *
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 *
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 *
19 * 3. Neither the name of the Institute nor the names of its contributors
20 *    may be used to endorse or promote products derived from this software
21 *    without specific prior written permission.
22 *
23 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
24 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
25 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
26 * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
27 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
28 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
29 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
30 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
32 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
33 * SUCH DAMAGE.
34 */
35
36#include "kdc_locl.h"
37#ifdef HAVE_UTIL_H
38#include <util.h>
39#endif
40
41#ifdef HAVE_CAPNG
42#include <cap-ng.h>
43#endif
44
45sig_atomic_t exit_flag = 0;
46
47#ifdef SUPPORT_DETACH
48int detach_from_console = -1;
49#endif
50
51static RETSIGTYPE
52sigterm(int sig)
53{
54    exit_flag = sig;
55}
56
57/*
58 * Allow dropping root bit, since heimdal reopens the database all the
59 * time the database needs to be owned by the user you are switched
60 * too. A better solution is to split the kdc in to more processes and
61 * run the network facing part with very low privilege.
62 */
63
64static void
65switch_environment(void)
66{
67#ifdef HAVE_GETEUID
68    if ((runas_string || chroot_string) && geteuid() != 0)
69	errx(1, "no running as root, can't switch user/chroot");
70
71    if (chroot_string && chroot(chroot_string) != 0)
72	errx(1, "chroot(%s)", "chroot_string failed");
73
74    if (runas_string) {
75	struct passwd *pw;
76
77	pw = getpwnam(runas_string);
78	if (pw == NULL)
79	    errx(1, "unknown user %s", runas_string);
80
81	if (initgroups(pw->pw_name, pw->pw_gid) < 0)
82	    err(1, "initgroups failed");
83
84#ifndef HAVE_CAPNG
85	if (setgid(pw->pw_gid) < 0)
86	    err(1, "setgid(%s) failed", runas_string);
87
88	if (setuid(pw->pw_uid) < 0)
89	    err(1, "setuid(%s)", runas_string);
90#else
91	capng_clear (CAPNG_EFFECTIVE | CAPNG_PERMITTED);
92	if (capng_updatev (CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
93	                   CAP_NET_BIND_SERVICE, CAP_SETPCAP, -1) < 0)
94	    err(1, "capng_updateev");
95
96	if (capng_change_id(pw->pw_uid, pw->pw_gid,
97	                    CAPNG_CLEAR_BOUNDING) < 0)
98	    err(1, "capng_change_id(%s)", runas_string);
99#endif
100    }
101#endif
102}
103
104
105int
106main(int argc, char **argv)
107{
108    krb5_error_code ret;
109    krb5_context context;
110    krb5_kdc_configuration *config;
111
112    setprogname(argv[0]);
113
114    ret = krb5_init_context(&context);
115    if (ret == KRB5_CONFIG_BADFORMAT)
116	errx (1, "krb5_init_context failed to parse configuration file");
117    else if (ret)
118	errx (1, "krb5_init_context failed: %d", ret);
119
120    ret = krb5_kt_register(context, &hdb_kt_ops);
121    if (ret)
122	errx (1, "krb5_kt_register(HDB) failed: %d", ret);
123
124    config = configure(context, argc, argv);
125
126#ifdef HAVE_SIGACTION
127    {
128	struct sigaction sa;
129
130	sa.sa_flags = 0;
131	sa.sa_handler = sigterm;
132	sigemptyset(&sa.sa_mask);
133
134	sigaction(SIGINT, &sa, NULL);
135	sigaction(SIGTERM, &sa, NULL);
136#ifdef SIGXCPU
137	sigaction(SIGXCPU, &sa, NULL);
138#endif
139
140	sa.sa_handler = SIG_IGN;
141#ifdef SIGPIPE
142	sigaction(SIGPIPE, &sa, NULL);
143#endif
144    }
145#else
146    signal(SIGINT, sigterm);
147    signal(SIGTERM, sigterm);
148#ifdef SIGXCPU
149    signal(SIGXCPU, sigterm);
150#endif
151#ifdef SIGPIPE
152    signal(SIGPIPE, SIG_IGN);
153#endif
154#endif
155#ifdef SUPPORT_DETACH
156    if (detach_from_console)
157	daemon(0, 0);
158#endif
159#ifdef __APPLE__
160    bonjour_announce(context, config);
161#endif
162    pidfile(NULL);
163
164    switch_environment();
165
166    loop(context, config);
167    krb5_free_context(context);
168    return 0;
169}
170