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 struct kadm_port {
  40     char *port;
  41     unsigned short def_port;
  42     struct kadm_port *next;
  43 } *kadm_ports;
  44
  45 static void
  46 add_kadm_port(krb5_context context, const char *service, unsigned int port)
  47 {
  48     struct kadm_port *p;
  49     p = malloc(sizeof(*p));
  50     if(p == NULL) {
  51         krb5_warnx(context, "failed to allocate %lu bytes\n",
  52                    (unsigned long)sizeof(*p));
  53         return;
  54     }
  55
  56     p->port = strdup(service);
  57     p->def_port = port;
  58
  59     p->next = kadm_ports;
  60     kadm_ports = p;
  61 }
  62
  63 static void
  64 add_standard_ports (krb5_context context)
  65 {
  66     add_kadm_port(context, "kerberos-adm", 749);
  67 }
  68
  69 /*
  70  * parse the set of space-delimited ports in `str' and add them.
  71  * "+" => all the standard ones
  72  * otherwise it's port|service[/protocol]
  73  */
  74
  75 void
  76 parse_ports(krb5_context context, const char *str)
  77 {
  78     char p[128];
  79
  80     while(strsep_copy(&str, " \t", p, sizeof(p)) != -1) {
  81         if(strcmp(p, "+") == 0)
  82             add_standard_ports(context);
  83         else
  84             add_kadm_port(context, p, 0);
  85     }
  86 }
  87
  88 static pid_t pgrp;
  89 sig_atomic_t term_flag, doing_useful_work;
  90
  91 static RETSIGTYPE
  92 sigchld(int sig)
  93 {
  94     int status;
  95     waitpid(-1, &status, 0);
  96     SIGRETURN(0);
  97 }
  98
  99 static RETSIGTYPE
 100 terminate(int sig)
 101 {
 102     if(getpid() == pgrp) {
 103         /* parent */
 104         term_flag = 1;
 105         signal(sig, SIG_IGN);
 106         killpg(pgrp, sig);
 107     } else {
 108         /* child */
 109         if(doing_useful_work)
 110             term_flag = 1;
 111         else
 112             exit(0);
 113     }
 114     SIGRETURN(0);
 115 }
 116
 117 static int
 118 spawn_child(krb5_context context, int *socks,
 119             unsigned int num_socks, int this_sock)
 120 {
 121     int e, i;
 122     struct sockaddr_storage __ss;
 123     struct sockaddr *sa = (struct sockaddr *)&__ss;
 124     socklen_t sa_size = sizeof(__ss);
 125     krb5_socket_t s;
 126     pid_t pid;
 127     krb5_address addr;
 128     char buf[128];
 129     size_t buf_len;
 130
 131     s = accept(socks[this_sock], sa, &sa_size);
 132     if(rk_IS_BAD_SOCKET(s)) {
 133         krb5_warn(context, rk_SOCK_ERRNO, "accept");
 134         return 1;
 135     }
 136     e = krb5_sockaddr2address(context, sa, &addr);
 137     if(e)
 138         krb5_warn(context, e, "krb5_sockaddr2address");
 139     else {
 140         e = krb5_print_address (&addr, buf, sizeof(buf),
 141                                 &buf_len);
 142         if(e)
 143             krb5_warn(context, e, "krb5_print_address");
 144         else
 145             krb5_warnx(context, "connection from %s", buf);
 146         krb5_free_address(context, &addr);
 147     }
 148
 149     pid = fork();
 150     if(pid == 0) {
 151         for(i = 0; i < num_socks; i++)
 152             rk_closesocket(socks[i]);
 153         dup2(s, STDIN_FILENO);
 154         dup2(s, STDOUT_FILENO);
 155         if(s != STDIN_FILENO && s != STDOUT_FILENO)
 156             rk_closesocket(s);
 157         return 0;
 158     } else {
 159         rk_closesocket(s);
 160     }
 161     return 1;
 162 }
 163
 164 static int
 165 wait_for_connection(krb5_context context,
 166                     krb5_socket_t *socks, unsigned int num_socks)
 167 {
 168     unsigned int i;
 169     int e;
 170     fd_set orig_read_set, read_set;
 171     int max_fd = -1;
 172
 173     FD_ZERO(&orig_read_set);
 174
 175     for(i = 0; i < num_socks; i++) {
 176 #ifdef FD_SETSIZE
 177         if (socks[i] >= FD_SETSIZE)
 178             errx (1, "fd too large");
 179 #endif
 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(rk_IS_SOCKET_ERROR(e)) {
 197             if(rk_SOCK_ERRNO != EINTR)
 198                 krb5_warn(context, rk_SOCK_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, const char *port_str)
 223 {
 224     int e;
 225     struct kadm_port *p;
 226
 227     krb5_socket_t *socks = NULL, *tmp;
 228     unsigned int num_socks = 0;
 229     int i;
 230
 231     if (port_str == NULL)
 232         port_str = "+";
 233
 234     parse_ports(context, port_str);
 235
 236     for(p = kadm_ports; p; p = p->next) {
 237         struct addrinfo hints, *ai, *ap;
 238         char portstr[32];
 239         memset (&hints, 0, sizeof(hints));
 240         hints.ai_flags    = AI_PASSIVE;
 241         hints.ai_socktype = SOCK_STREAM;
 242
 243         e = getaddrinfo(NULL, p->port, &hints, &ai);
 244         if(e) {
 245             snprintf(portstr, sizeof(portstr), "%u", p->def_port);
 246             e = getaddrinfo(NULL, portstr, &hints, &ai);
 247         }
 248
 249         if(e) {
 250             krb5_warn(context, krb5_eai_to_heim_errno(e, errno),
 251                       "%s", portstr);
 252             continue;
 253         }
 254         i = 0;
 255         for(ap = ai; ap; ap = ap->ai_next)
 256             i++;
 257         tmp = realloc(socks, (num_socks + i) * sizeof(*socks));
 258         if(tmp == NULL) {
 259             krb5_warnx(context, "failed to reallocate %lu bytes",
 260                        (unsigned long)(num_socks + i) * sizeof(*socks));
 261             continue;
 262         }
 263         socks = tmp;
 264         for(ap = ai; ap; ap = ap->ai_next) {
 265             krb5_socket_t s = socket(ap->ai_family, ap->ai_socktype, ap->ai_protocol);
 266             if(rk_IS_BAD_SOCKET(s)) {
 267                 krb5_warn(context, rk_SOCK_ERRNO, "socket");
 268                 continue;
 269             }
 270
 271             socket_set_reuseaddr(s, 1);
 272             socket_set_ipv6only(s, 1);
 273
 274             if (rk_IS_SOCKET_ERROR(bind (s, ap->ai_addr, ap->ai_addrlen))) {
 275                 krb5_warn(context, rk_SOCK_ERRNO, "bind");
 276                 rk_closesocket(s);
 277                 continue;
 278             }
 279             if (rk_IS_SOCKET_ERROR(listen (s, SOMAXCONN))) {
 280                 krb5_warn(context, rk_SOCK_ERRNO, "listen");
 281                 rk_closesocket(s);
 282                 continue;
 283             }
 284             socks[num_socks++] = s;
 285         }
 286         freeaddrinfo (ai);
 287     }
 288     if(num_socks == 0)
 289         krb5_errx(context, 1, "no sockets to listen to - exiting");
 290
 291     return wait_for_connection(context, socks, num_socks);
 292 }