kdc/main.c

   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
  45 sig_atomic_t exit_flag = 0;
  46
  47 int detach_from_console = -1;
  48 int daemon_child = -1;
  49
  50 static RETSIGTYPE
  51 sigterm(int sig)
  52 {
  53     exit_flag = sig;
  54 }
  55
  56 /*
  57  * Allow dropping root bit, since heimdal reopens the database all the
  58  * time the database needs to be owned by the user you are switched
  59  * too. A better solution is to split the kdc in to more processes and
  60  * run the network facing part with very low privilege.
  61  */
  62
  63 static void
  64 switch_environment(void)
  65 {
  66 #ifdef HAVE_GETEUID
  67     if ((runas_string || chroot_string) && geteuid() != 0)
  68         errx(1, "no running as root, can't switch user/chroot");
  69
  70     if (chroot_string) {
  71         if (chroot(chroot_string))
  72             err(1, "chroot(%s) failed", chroot_string);
  73         if (chdir("/"))
  74             err(1, "chdir(/) after chroot failed");
  75     }
  76
  77     if (runas_string) {
  78         struct passwd *pw;
  79
  80         pw = getpwnam(runas_string);
  81         if (pw == NULL)
  82             errx(1, "unknown user %s", runas_string);
  83
  84         if (initgroups(pw->pw_name, pw->pw_gid) < 0)
  85             err(1, "initgroups failed");
  86
  87 #ifndef HAVE_CAPNG
  88         if (setgid(pw->pw_gid) < 0)
  89             err(1, "setgid(%s) failed", runas_string);
  90
  91         if (setuid(pw->pw_uid) < 0)
  92             err(1, "setuid(%s)", runas_string);
  93 #else
  94         capng_clear (CAPNG_EFFECTIVE | CAPNG_PERMITTED);
  95         if (capng_updatev (CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
  96                            CAP_NET_BIND_SERVICE, CAP_SETPCAP, -1) < 0)
  97             err(1, "capng_updateev");
  98
  99         if (capng_change_id(pw->pw_uid, pw->pw_gid,
 100                             CAPNG_CLEAR_BOUNDING) < 0)
 101             err(1, "capng_change_id(%s)", runas_string);
 102 #endif
 103     }
 104 #endif
 105 }
 106
 107 int
 108 main(int argc, char **argv)
 109 {
 110     krb5_error_code ret;
 111     krb5_context context;
 112     krb5_kdc_configuration *config;
 113     int optidx = 0;
 114
 115     setprogname(argv[0]);
 116
 117     ret = krb5_init_context(&context);
 118     if (ret == KRB5_CONFIG_BADFORMAT)
 119         errx (1, "krb5_init_context failed to parse configuration file");
 120     else if (ret)
 121         errx (1, "krb5_init_context failed: %d", ret);
 122
 123     ret = krb5_kt_register(context, &hdb_get_kt_ops);
 124     if (ret)
 125         errx (1, "krb5_kt_register(HDB) failed: %d", ret);
 126
 127     config = configure(context, argc, argv, &optidx);
 128
 129 #ifdef HAVE_SIGACTION
 130     {
 131         struct sigaction sa;
 132
 133         sa.sa_flags = 0;
 134         sa.sa_handler = sigterm;
 135         sigemptyset(&sa.sa_mask);
 136
 137         sigaction(SIGINT, &sa, NULL);
 138         sigaction(SIGTERM, &sa, NULL);
 139 #ifdef SIGXCPU
 140         sigaction(SIGXCPU, &sa, NULL);
 141 #endif
 142
 143         sa.sa_handler = SIG_IGN;
 144 #ifdef SIGPIPE
 145         sigaction(SIGPIPE, &sa, NULL);
 146 #endif
 147     }
 148 #else
 149     signal(SIGINT, sigterm);
 150     signal(SIGTERM, sigterm);
 151 #ifdef SIGXCPU
 152     signal(SIGXCPU, sigterm);
 153 #endif
 154 #ifdef SIGPIPE
 155     signal(SIGPIPE, SIG_IGN);
 156 #endif
 157 #endif
 158 #ifdef __APPLE__
 159     bonjour_announce(context, config);
 160 #endif
 161     pidfile(NULL);
 162
 163     switch_environment();
 164
 165     loop(context, config);
 166     krb5_free_context(context);
 167     return 0;
 168 }