kadmin/kadm_conn.c

   1 /*
   2  * Copyright (c) 2000 - 2004 Kungliga Tekniska Högskolan
   3  * (Royal Institute of Technology, Stockholm, Sweden).
   4  * All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  *
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  *
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  *
  17  * 3. Neither the name of the Institute nor the names of its contributors
  18  *    may be used to endorse or promote products derived from this software
  19  *    without specific prior written permission.
  20  *
  21  * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE AND CONTRIBUTORS ``AS IS'' AND
  22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE INSTITUTE OR CONTRIBUTORS BE LIABLE
  25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31  * SUCH DAMAGE.
  32  */
  33
  34 #include "kadmin_locl.h"
  35 #ifdef HAVE_SYS_WAIT_H
  36 #include <sys/wait.h>
  37 #endif
  38
  39 RCSID("$Id$");
  40
  41 struct kadm_port {
  42     char *port;
  43     unsigned short def_port;
  44     struct kadm_port *next;
  45 } *kadm_ports;
  46
  47 static void
  48 add_kadm_port(krb5_context context, const char *service, unsigned int port)
  49 {
  50     struct kadm_port *p;
  51     p = malloc(sizeof(*p));
  52     if(p == NULL) {
  53         krb5_warnx(context, "failed to allocate %lu bytes\n",
  54                    (unsigned long)sizeof(*p));
  55         return;
  56     }
  57
  58     p->port = strdup(service);
  59     p->def_port = port;
  60
  61     p->next = kadm_ports;
  62     kadm_ports = p;
  63 }
  64
  65 static void
  66 add_standard_ports (krb5_context context)
  67 {
  68     add_kadm_port(context, "kerberos-adm", 749);
  69 }
  70
  71 /*
  72  * parse the set of space-delimited ports in `str' and add them.
  73  * "+" => all the standard ones
  74  * otherwise it's port|service[/protocol]
  75  */
  76
  77 void
  78 parse_ports(krb5_context context, const char *str)
  79 {
  80     char p[128];
  81
  82     while(strsep_copy(&str, " \t", p, sizeof(p)) != -1) {
  83         if(strcmp(p, "+") == 0)
  84             add_standard_ports(context);
  85         else
  86             add_kadm_port(context, p, 0);
  87     }
  88 }
  89
  90 static pid_t pgrp;
  91 sig_atomic_t term_flag, doing_useful_work;
  92
  93 static RETSIGTYPE
  94 sigchld(int sig)
  95 {
  96     int status;
  97     waitpid(-1, &status, 0);
  98     SIGRETURN(0);
  99 }
 100
 101 static RETSIGTYPE
 102 terminate(int sig)
 103 {
 104     if(getpid() == pgrp) {
 105         /* parent */
 106         term_flag = 1;
 107         signal(sig, SIG_IGN);
 108         killpg(pgrp, sig);
 109     } else {
 110         /* child */
 111         if(doing_useful_work)
 112             term_flag = 1;
 113         else
 114             exit(0);
 115     }
 116     SIGRETURN(0);
 117 }
 118
 119 static int
 120 spawn_child(krb5_context context, int *socks,
 121             unsigned int num_socks, int this_sock)
 122 {
 123     int e, i;
 124     struct sockaddr_storage __ss;
 125     struct sockaddr *sa = (struct sockaddr *)&__ss;
 126     socklen_t sa_size = sizeof(__ss);
 127     int s;
 128     pid_t pid;
 129     krb5_address addr;
 130     char buf[128];
 131     size_t buf_len;
 132
 133     s = accept(socks[this_sock], sa, &sa_size);
 134     if(s < 0) {
 135         krb5_warn(context, errno, "accept");
 136         return 1;
 137     }
 138     e = krb5_sockaddr2address(context, sa, &addr);
 139     if(e)
 140         krb5_warn(context, e, "krb5_sockaddr2address");
 141     else {
 142         e = krb5_print_address (&addr, buf, sizeof(buf),
 143                                 &buf_len);
 144         if(e)
 145             krb5_warn(context, e, "krb5_print_address");
 146         else
 147             krb5_warnx(context, "connection from %s", buf);
 148         krb5_free_address(context, &addr);
 149     }
 150
 151     pid = fork();
 152     if(pid == 0) {
 153         for(i = 0; i < num_socks; i++)
 154             close(socks[i]);
 155         dup2(s, STDIN_FILENO);
 156         dup2(s, STDOUT_FILENO);
 157         if(s != STDIN_FILENO && s != STDOUT_FILENO)
 158             close(s);
 159         return 0;
 160     } else {
 161         close(s);
 162     }
 163     return 1;
 164 }
 165
 166 static int
 167 wait_for_connection(krb5_context context,
 168                     int *socks, unsigned int num_socks)
 169 {
 170     unsigned int i;
 171     int e;
 172     fd_set orig_read_set, read_set;
 173     int max_fd = -1;
 174
 175     FD_ZERO(&orig_read_set);
 176
 177     for(i = 0; i < num_socks; i++) {
 178         if (socks[i] >= FD_SETSIZE)
 179             errx (1, "fd too large");
 180         FD_SET(socks[i], &orig_read_set);
 181         max_fd = max(max_fd, socks[i]);
 182     }
 183
 184     pgrp = getpid();
 185
 186     if(setpgid(0, pgrp) < 0)
 187         err(1, "setpgid");
 188
 189     signal(SIGTERM, terminate);
 190     signal(SIGINT, terminate);
 191     signal(SIGCHLD, sigchld);
 192
 193     while (term_flag == 0) {
 194         read_set = orig_read_set;
 195         e = select(max_fd + 1, &read_set, NULL, NULL, NULL);
 196         if(e < 0) {
 197             if(errno != EINTR)
 198                 krb5_warn(context, errno, "select");
 199         } else if(e == 0)
 200             krb5_warnx(context, "select returned 0");
 201         else {
 202             for(i = 0; i < num_socks; i++) {
 203                 if(FD_ISSET(socks[i], &read_set))
 204                     if(spawn_child(context, socks, num_socks, i) == 0)
 205                         return 0;
 206             }
 207         }
 208     }
 209     signal(SIGCHLD, SIG_IGN);
 210     while(1) {
 211         int status;
 212         pid_t pid;
 213         pid = waitpid(-1, &status, 0);
 214         if(pid == -1 && errno == ECHILD)
 215             break;
 216     }
 217     exit(0);
 218 }
 219
 220
 221 int
 222 start_server(krb5_context context)
 223 {
 224     int e;
 225     struct kadm_port *p;
 226
 227     int *socks = NULL, *tmp;
 228     unsigned int num_socks = 0;
 229     int i;
 230
 231     for(p = kadm_ports; p; p = p->next) {
 232         struct addrinfo hints, *ai, *ap;
 233         char portstr[32];
 234         memset (&hints, 0, sizeof(hints));
 235         hints.ai_flags    = AI_PASSIVE;
 236         hints.ai_socktype = SOCK_STREAM;
 237
 238         e = getaddrinfo(NULL, p->port, &hints, &ai);
 239         if(e) {
 240             snprintf(portstr, sizeof(portstr), "%u", p->def_port);
 241             e = getaddrinfo(NULL, portstr, &hints, &ai);
 242         }
 243
 244         if(e) {
 245             krb5_warn(context, krb5_eai_to_heim_errno(e, errno),
 246                       "%s", portstr);
 247             continue;
 248         }
 249         i = 0;
 250         for(ap = ai; ap; ap = ap->ai_next)
 251             i++;
 252         tmp = realloc(socks, (num_socks + i) * sizeof(*socks));
 253         if(tmp == NULL) {
 254             krb5_warnx(context, "failed to reallocate %lu bytes",
 255                        (unsigned long)(num_socks + i) * sizeof(*socks));
 256             continue;
 257         }
 258         socks = tmp;
 259         for(ap = ai; ap; ap = ap->ai_next) {
 260             int s = socket(ap->ai_family, ap->ai_socktype, ap->ai_protocol);
 261             if(s < 0) {
 262                 krb5_warn(context, errno, "socket");
 263                 continue;
 264             }
 265
 266             socket_set_reuseaddr(s, 1);
 267             socket_set_ipv6only(s, 1);
 268
 269             if (bind (s, ap->ai_addr, ap->ai_addrlen) < 0) {
 270                 krb5_warn(context, errno, "bind");
 271                 close(s);
 272                 continue;
 273             }
 274             if (listen (s, SOMAXCONN) < 0) {
 275                 krb5_warn(context, errno, "listen");
 276                 close(s);
 277                 continue;
 278             }
 279             socks[num_socks++] = s;
 280         }
 281         freeaddrinfo (ai);
 282     }
 283     if(num_socks == 0)
 284         krb5_errx(context, 1, "no sockets to listen to - exiting");
 285     return wait_for_connection(context, socks, num_socks);
 286 }