kadmin/kadm_conn.c

   1 /*
   2  * Copyright (c) 2000 - 2001 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 extern int do_kerberos4;
  66
  67 static void
  68 add_standard_ports (krb5_context context)
  69 {
  70     add_kadm_port(context, "kerberos-adm", 749);
  71 #ifdef KRB4
  72     if(do_kerberos4)
  73         add_kadm_port(context, "kerberos-master", 751);
  74 #endif
  75 }
  76
  77 /*
  78  * parse the set of space-delimited ports in `str' and add them.
  79  * "+" => all the standard ones
  80  * otherwise it's port|service[/protocol]
  81  */
  82
  83 void
  84 parse_ports(krb5_context context, const char *str)
  85 {
  86     char p[128];
  87
  88     while(strsep_copy(&str, " \t", p, sizeof(p)) != -1) {
  89         if(strcmp(p, "+") == 0)
  90             add_standard_ports(context);
  91         else
  92             add_kadm_port(context, p, 0);
  93     }
  94 }
  95
  96 static pid_t pgrp;
  97 sig_atomic_t term_flag, doing_useful_work;
  98
  99 static RETSIGTYPE
 100 sigchld(int sig)
 101 {
 102     int status;
 103     waitpid(-1, &status, 0);
 104     SIGRETURN(0);
 105 }
 106
 107 static RETSIGTYPE
 108 terminate(int sig)
 109 {
 110     if(getpid() == pgrp) {
 111         /* parent */
 112         term_flag = 1;
 113         signal(sig, SIG_IGN);
 114         killpg(pgrp, sig);
 115     } else {
 116         /* child */
 117         if(doing_useful_work)
 118             term_flag = 1;
 119         else
 120             exit(0);
 121     }
 122     SIGRETURN(0);
 123 }
 124
 125 static int
 126 spawn_child(krb5_context context, int *socks, int num_socks, int this_sock)
 127 {
 128     int e, i;
 129     struct sockaddr_storage __ss;
 130     struct sockaddr *sa = (struct sockaddr *)&__ss;
 131     socklen_t sa_size = sizeof(__ss);
 132     int s;
 133     pid_t pid;
 134     krb5_address addr;
 135     char buf[128];
 136     size_t buf_len;
 137
 138     s = accept(socks[this_sock], sa, &sa_size);
 139     if(s < 0) {
 140         krb5_warn(context, errno, "accept");
 141         return 1;
 142     }
 143     e = krb5_sockaddr2address(context, sa, &addr);
 144     if(e)
 145         krb5_warn(context, e, "krb5_sockaddr2address");
 146     else {
 147         e = krb5_print_address (&addr, buf, sizeof(buf),
 148                                 &buf_len);
 149         if(e)
 150             krb5_warn(context, e, "krb5_print_address");
 151         else
 152             krb5_warnx(context, "connection from %s", buf);
 153         krb5_free_address(context, &addr);
 154     }
 155
 156     pid = fork();
 157     if(pid == 0) {
 158         for(i = 0; i < num_socks; i++)
 159             close(socks[i]);
 160         dup2(s, STDIN_FILENO);
 161         dup2(s, STDOUT_FILENO);
 162         if(s != STDIN_FILENO && s != STDOUT_FILENO)
 163             close(s);
 164         return 0;
 165     } else {
 166         close(s);
 167     }
 168     return 1;
 169 }
 170
 171 static int
 172 wait_for_connection(krb5_context context,
 173                     int *socks, int num_socks)
 174 {
 175     int i, e;
 176     fd_set orig_read_set, read_set;
 177     int max_fd = -1;
 178
 179     FD_ZERO(&orig_read_set);
 180
 181     for(i = 0; i < num_socks; i++) {
 182         if (socks[i] >= FD_SETSIZE)
 183             errx (1, "fd too large");
 184         FD_SET(socks[i], &orig_read_set);
 185         max_fd = max(max_fd, socks[i]);
 186     }
 187
 188     pgrp = getpid();
 189
 190     if(setpgid(0, pgrp) < 0)
 191         err(1, "setpgid");
 192
 193     signal(SIGTERM, terminate);
 194     signal(SIGINT, terminate);
 195     signal(SIGCHLD, sigchld);
 196
 197     while (term_flag == 0) {
 198         read_set = orig_read_set;
 199         e = select(max_fd + 1, &read_set, NULL, NULL, NULL);
 200         if(e < 0) {
 201             if(errno != EINTR)
 202                 krb5_warn(context, errno, "select");
 203         } else if(e == 0)
 204             krb5_warnx(context, "select returned 0");
 205         else {
 206             for(i = 0; i < num_socks; i++) {
 207                 if(FD_ISSET(socks[i], &read_set))
 208                     if(spawn_child(context, socks, num_socks, i) == 0)
 209                         return 0;
 210             }
 211         }
 212     }
 213     signal(SIGCHLD, SIG_IGN);
 214     while(1) {
 215         int status;
 216         pid_t pid;
 217         pid = waitpid(-1, &status, 0);
 218         if(pid == -1 && errno == ECHILD)
 219             break;
 220     }
 221     exit(0);
 222 }
 223
 224
 225 int
 226 start_server(krb5_context context)
 227 {
 228     int e;
 229     struct kadm_port *p;
 230
 231     int *socks = NULL, *tmp;
 232     int num_socks = 0;
 233     int i;
 234
 235     for(p = kadm_ports; p; p = p->next) {
 236         struct addrinfo hints, *ai, *ap;
 237         char portstr[32];
 238         memset (&hints, 0, sizeof(hints));
 239         hints.ai_flags    = AI_PASSIVE;
 240         hints.ai_socktype = SOCK_STREAM;
 241
 242         e = getaddrinfo(NULL, p->port, &hints, &ai);
 243         if(e) {
 244             snprintf(portstr, sizeof(portstr), "%u", p->def_port);
 245             e = getaddrinfo(NULL, portstr, &hints, &ai);
 246         }
 247
 248         if(e) {
 249             krb5_warn(context, krb5_eai_to_heim_errno(e, errno),
 250                       "%s", portstr);
 251             continue;
 252         }
 253         i = 0;
 254         for(ap = ai; ap; ap = ap->ai_next)
 255             i++;
 256         tmp = realloc(socks, (num_socks + i) * sizeof(*socks));
 257         if(tmp == NULL) {
 258             krb5_warnx(context, "failed to reallocate %lu bytes",
 259                        (unsigned long)(num_socks + i) * sizeof(*socks));
 260             continue;
 261         }
 262         socks = tmp;
 263         for(ap = ai; ap; ap = ap->ai_next) {
 264             int one = 1;
 265             int s = socket(ap->ai_family, ap->ai_socktype, ap->ai_protocol);
 266             if(s < 0) {
 267                 krb5_warn(context, errno, "socket");
 268                 continue;
 269             }
 270 #if defined(SO_REUSEADDR) && defined(HAVE_SETSOCKOPT)
 271             if(setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (void *)&one,
 272                           sizeof(one)) < 0)
 273                 krb5_warn(context, errno, "setsockopt");
 274 #endif
 275             if (bind (s, ap->ai_addr, ap->ai_addrlen) < 0) {
 276                 krb5_warn(context, errno, "bind");
 277                 close(s);
 278                 continue;
 279             }
 280             if (listen (s, SOMAXCONN) < 0) {
 281                 krb5_warn(context, errno, "listen");
 282                 close(s);
 283                 continue;
 284             }
 285             socks[num_socks++] = s;
 286         }
 287         freeaddrinfo (ai);
 288     }
 289     if(num_socks == 0)
 290         krb5_errx(context, 1, "no sockets to listen to - exiting");
 291     return wait_for_connection(context, socks, num_socks);
 292 }