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 sigchld(int sig)
  52 {
  53 }
  54
  55 static RETSIGTYPE
  56 sigterm(int sig)
  57 {
  58     exit_flag = sig;
  59 }
  60
  61 /*
  62  * Allow dropping root bit, since heimdal reopens the database all the
  63  * time the database needs to be owned by the user you are switched
  64  * too. A better solution is to split the kdc in to more processes and
  65  * run the network facing part with very low privilege.
  66  */
  67
  68 static void
  69 switch_environment(void)
  70 {
  71 #ifdef HAVE_GETEUID
  72     if ((runas_string || chroot_string) && geteuid() != 0)
  73         errx(1, "no running as root, can't switch user/chroot");
  74
  75     if (chroot_string) {
  76         if (chroot(chroot_string))
  77             err(1, "chroot(%s) failed", chroot_string);
  78         if (chdir("/"))
  79             err(1, "chdir(/) after chroot failed");
  80     }
  81
  82     if (runas_string) {
  83         struct passwd *pw;
  84
  85         pw = getpwnam(runas_string);
  86         if (pw == NULL)
  87             errx(1, "unknown user %s", runas_string);
  88
  89         if (initgroups(pw->pw_name, pw->pw_gid) < 0)
  90             err(1, "initgroups failed");
  91
  92 #ifndef HAVE_CAPNG
  93         if (setgid(pw->pw_gid) < 0)
  94             err(1, "setgid(%s) failed", runas_string);
  95
  96         if (setuid(pw->pw_uid) < 0)
  97             err(1, "setuid(%s)", runas_string);
  98 #else
  99         capng_clear (CAPNG_EFFECTIVE | CAPNG_PERMITTED);
 100         if (capng_updatev (CAPNG_ADD, CAPNG_EFFECTIVE | CAPNG_PERMITTED,
 101                            CAP_NET_BIND_SERVICE, CAP_SETPCAP, -1) < 0)
 102             err(1, "capng_updateev");
 103
 104         if (capng_change_id(pw->pw_uid, pw->pw_gid,
 105                             CAPNG_CLEAR_BOUNDING) < 0)
 106             err(1, "capng_change_id(%s)", runas_string);
 107 #endif
 108     }
 109 #endif
 110 }
 111
 112 int
 113 main(int argc, char **argv)
 114 {
 115     krb5_error_code ret;
 116     krb5_context context;
 117     krb5_kdc_configuration *config;
 118     int optidx = 0;
 119
 120     setprogname(argv[0]);
 121
 122     ret = krb5_init_context(&context);
 123     if (ret == KRB5_CONFIG_BADFORMAT)
 124         errx (1, "krb5_init_context failed to parse configuration file");
 125     else if (ret)
 126         errx (1, "krb5_init_context failed: %d", ret);
 127
 128     ret = krb5_kt_register(context, &hdb_get_kt_ops);
 129     if (ret)
 130         errx (1, "krb5_kt_register(HDB) failed: %d", ret);
 131
 132     config = configure(context, argc, argv, &optidx);
 133
 134 #ifdef HAVE_SIGACTION
 135     {
 136         struct sigaction sa;
 137
 138         sa.sa_flags = 0;
 139         sa.sa_handler = sigterm;
 140         sigemptyset(&sa.sa_mask);
 141
 142         sigaction(SIGINT, &sa, NULL);
 143         sigaction(SIGTERM, &sa, NULL);
 144 #ifdef SIGXCPU
 145         sigaction(SIGXCPU, &sa, NULL);
 146 #endif
 147
 148 #ifdef SIGCHLD
 149         sa.sa_handler = sigchld;
 150         sigaction(SIGCHLD, &sa, NULL);
 151 #endif
 152
 153         sa.sa_handler = SIG_IGN;
 154 #ifdef SIGPIPE
 155         sigaction(SIGPIPE, &sa, NULL);
 156 #endif
 157     }
 158 #else
 159     signal(SIGINT, sigterm);
 160     signal(SIGTERM, sigterm);
 161 #ifdef SIGCHLD
 162     signal(SIGCHLD, sigchld);
 163 #endif
 164 #ifdef SIGXCPU
 165     signal(SIGXCPU, sigterm);
 166 #endif
 167 #ifdef SIGPIPE
 168     signal(SIGPIPE, SIG_IGN);
 169 #endif
 170 #endif
 171     pidfile(NULL);
 172
 173     switch_environment();
 174
 175     start_kdc(context, config);
 176     krb5_free_context(context);
 177     return 0;
 178 }