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 #ifdef SUPPORT_DETACH
  48 int detach_from_console = -1;
  49 #endif
  50
  51 static RETSIGTYPE
  52 sigterm(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
  64 static void
  65 switch_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) {
  72         if (chroot(chroot_string))
  73             err(1, "chroot(%s) failed", chroot_string);
  74         if (chdir("/"))
  75             err(1, "chdir(/) after chroot failed");
  76     }
  77
  78     if (runas_string) {
  79         struct passwd *pw;
  80
  81         pw = getpwnam(runas_string);
  82         if (pw == NULL)
  83             errx(1, "unknown user %s", runas_string);
  84
  85         if (initgroups(pw->pw_name, pw->pw_gid) < 0)
  86             err(1, "initgroups failed");
  87
  88 #ifndef HAVE_CAPNG
  89         if (setgid(pw->pw_gid) < 0)
  90             err(1, "setgid(%s) failed", runas_string);
  91
  92         if (setuid(pw->pw_uid) < 0)
  93             err(1, "setuid(%s)", runas_string);
  94 #else
  95         capng_clear (CAPNG_EFFECTIVE | CAPNG_PERMITTED);
  96         if (capng_updatev (CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
  97                            CAP_NET_BIND_SERVICE, CAP_SETPCAP, -1) < 0)
  98             err(1, "capng_updateev");
  99
 100         if (capng_change_id(pw->pw_uid, pw->pw_gid,
 101                             CAPNG_CLEAR_BOUNDING) < 0)
 102             err(1, "capng_change_id(%s)", runas_string);
 103 #endif
 104     }
 105 #endif
 106 }
 107
 108
 109 int
 110 main(int argc, char **argv)
 111 {
 112     krb5_error_code ret;
 113     krb5_context context;
 114     krb5_kdc_configuration *config;
 115     int optidx = 0;
 116
 117     setprogname(argv[0]);
 118
 119     ret = krb5_init_context(&context);
 120     if (ret == KRB5_CONFIG_BADFORMAT)
 121         errx (1, "krb5_init_context failed to parse configuration file");
 122     else if (ret)
 123         errx (1, "krb5_init_context failed: %d", ret);
 124
 125     ret = krb5_kt_register(context, &hdb_get_kt_ops);
 126     if (ret)
 127         errx (1, "krb5_kt_register(HDB) failed: %d", ret);
 128
 129     config = configure(context, argc, argv, &optidx);
 130
 131 #ifdef HAVE_SIGACTION
 132     {
 133         struct sigaction sa;
 134
 135         sa.sa_flags = 0;
 136         sa.sa_handler = sigterm;
 137         sigemptyset(&sa.sa_mask);
 138
 139         sigaction(SIGINT, &sa, NULL);
 140         sigaction(SIGTERM, &sa, NULL);
 141 #ifdef SIGXCPU
 142         sigaction(SIGXCPU, &sa, NULL);
 143 #endif
 144
 145         sa.sa_handler = SIG_IGN;
 146 #ifdef SIGPIPE
 147         sigaction(SIGPIPE, &sa, NULL);
 148 #endif
 149     }
 150 #else
 151     signal(SIGINT, sigterm);
 152     signal(SIGTERM, sigterm);
 153 #ifdef SIGXCPU
 154     signal(SIGXCPU, sigterm);
 155 #endif
 156 #ifdef SIGPIPE
 157     signal(SIGPIPE, SIG_IGN);
 158 #endif
 159 #endif
 160 #ifdef SUPPORT_DETACH
 161     if (detach_from_console)
 162         daemon(0, 0);
 163 #endif
 164 #ifdef __APPLE__
 165     bonjour_announce(context, config);
 166 #endif
 167     pidfile(NULL);
 168
 169     switch_environment();
 170
 171     loop(context, config);
 172     krb5_free_context(context);
 173     return 0;
 174 }