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 extern int daemon_child;
  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 contextp, const char *service, unsigned int port)
  49 {
  50     struct kadm_port *p;
  51     p = malloc(sizeof(*p));
  52     if(p == NULL) {
  53         krb5_warnx(contextp, "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 contextp)
  67 {
  68     add_kadm_port(contextp, "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 contextp, 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(contextp);
  85         else
  86             add_kadm_port(contextp, 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     /*
  98      * waitpid() is async safe. will return -1 or 0 on no more zombie
  99      * children
 100      */
 101     while ((waitpid(-1, &status, WNOHANG)) > 0)
 102         ;
 103     SIGRETURN(0);
 104 }
 105
 106 static RETSIGTYPE
 107 terminate(int sig)
 108 {
 109     if(getpid() == pgrp) {
 110         /* parent */
 111         term_flag = 1;
 112         signal(sig, SIG_IGN);
 113         killpg(pgrp, sig);
 114     } else {
 115         /* child */
 116         if(doing_useful_work)
 117             term_flag = 1;
 118         else
 119             exit(0);
 120     }
 121     SIGRETURN(0);
 122 }
 123
 124 static int
 125 spawn_child(krb5_context contextp, int *socks,
 126             unsigned int num_socks, int this_sock)
 127 {
 128     int e;
 129     size_t i;
 130     struct sockaddr_storage __ss;
 131     struct sockaddr *sa = (struct sockaddr *)&__ss;
 132     socklen_t sa_size = sizeof(__ss);
 133     krb5_socket_t s;
 134     pid_t pid;
 135     krb5_address addr;
 136     char buf[128];
 137     size_t buf_len;
 138
 139     s = accept(socks[this_sock], sa, &sa_size);
 140     if(rk_IS_BAD_SOCKET(s)) {
 141         krb5_warn(contextp, rk_SOCK_ERRNO, "accept");
 142         return 1;
 143     }
 144     e = krb5_sockaddr2address(contextp, sa, &addr);
 145     if(e)
 146         krb5_warn(contextp, e, "krb5_sockaddr2address");
 147     else {
 148         e = krb5_print_address (&addr, buf, sizeof(buf),
 149                                 &buf_len);
 150         if(e)
 151             krb5_warn(contextp, e, "krb5_print_address");
 152         else
 153             krb5_warnx(contextp, "connection from %s", buf);
 154         krb5_free_address(contextp, &addr);
 155     }
 156
 157     pid = fork();
 158     if(pid == 0) {
 159         for(i = 0; i < num_socks; i++)
 160             rk_closesocket(socks[i]);
 161         dup2(s, STDIN_FILENO);
 162         dup2(s, STDOUT_FILENO);
 163         if(s != STDIN_FILENO && s != STDOUT_FILENO)
 164             rk_closesocket(s);
 165         return 0;
 166     } else {
 167         rk_closesocket(s);
 168     }
 169     return 1;
 170 }
 171
 172 static void
 173 wait_for_connection(krb5_context contextp,
 174                     krb5_socket_t *socks, unsigned int num_socks)
 175 {
 176     unsigned int i;
 177     int e;
 178     fd_set orig_read_set, read_set;
 179     int status, max_fd = -1;
 180
 181     FD_ZERO(&orig_read_set);
 182
 183     for(i = 0; i < num_socks; i++) {
 184 #ifdef FD_SETSIZE
 185         if (socks[i] >= FD_SETSIZE)
 186             errx (1, "fd too large");
 187 #endif
 188         FD_SET(socks[i], &orig_read_set);
 189         max_fd = max(max_fd, socks[i]);
 190     }
 191
 192     pgrp = getpid();
 193
 194     /* systemd may cause setpgid to fail with EPERM */
 195     if(setpgid(0, pgrp) < 0 && errno != EPERM)
 196         err(1, "setpgid");
 197
 198     signal(SIGTERM, terminate);
 199     signal(SIGINT, terminate);
 200     signal(SIGCHLD, sigchld);
 201
 202     while (term_flag == 0) {
 203         read_set = orig_read_set;
 204         e = select(max_fd + 1, &read_set, NULL, NULL, NULL);
 205         if(rk_IS_SOCKET_ERROR(e)) {
 206             if(rk_SOCK_ERRNO != EINTR)
 207                 krb5_warn(contextp, rk_SOCK_ERRNO, "select");
 208         } else if(e == 0)
 209             krb5_warnx(contextp, "select returned 0");
 210         else {
 211             for(i = 0; i < num_socks; i++) {
 212                 if(FD_ISSET(socks[i], &read_set))
 213                     if(spawn_child(contextp, socks, num_socks, i) == 0)
 214                         return;
 215             }
 216         }
 217     }
 218     signal(SIGCHLD, SIG_IGN);
 219
 220     while ((waitpid(-1, &status, WNOHANG)) > 0)
 221         ;
 222
 223     exit(0);
 224 }
 225
 226
 227 void
 228 start_server(krb5_context contextp, const char *port_str)
 229 {
 230     int e;
 231     struct kadm_port *p;
 232
 233     krb5_socket_t *socks = NULL, *tmp;
 234     unsigned int num_socks = 0;
 235     int i;
 236
 237     if (port_str == NULL)
 238         port_str = "+";
 239
 240     parse_ports(contextp, port_str);
 241
 242     for(p = kadm_ports; p; p = p->next) {
 243         struct addrinfo hints, *ai, *ap;
 244         char portstr[32];
 245         memset (&hints, 0, sizeof(hints));
 246         hints.ai_flags    = AI_PASSIVE;
 247         hints.ai_socktype = SOCK_STREAM;
 248
 249         e = getaddrinfo(NULL, p->port, &hints, &ai);
 250         if(e) {
 251             snprintf(portstr, sizeof(portstr), "%u", p->def_port);
 252             e = getaddrinfo(NULL, portstr, &hints, &ai);
 253         }
 254
 255         if(e) {
 256             krb5_warn(contextp, krb5_eai_to_heim_errno(e, errno),
 257                       "%s", portstr);
 258             continue;
 259         }
 260         i = 0;
 261         for(ap = ai; ap; ap = ap->ai_next)
 262             i++;
 263         tmp = realloc(socks, (num_socks + i) * sizeof(*socks));
 264         if(tmp == NULL)
 265             krb5_err(contextp, 1, errno, "failed to reallocate %lu bytes",
 266                      (unsigned long)(num_socks + i) * sizeof(*socks));
 267         socks = tmp;
 268         for(ap = ai; ap; ap = ap->ai_next) {
 269             krb5_socket_t s = socket(ap->ai_family, ap->ai_socktype, ap->ai_protocol);
 270             if(rk_IS_BAD_SOCKET(s)) {
 271                 krb5_warn(contextp, rk_SOCK_ERRNO, "socket");
 272                 continue;
 273             }
 274
 275             socket_set_reuseaddr(s, 1);
 276             socket_set_ipv6only(s, 1);
 277
 278             if (rk_IS_SOCKET_ERROR(bind (s, ap->ai_addr, ap->ai_addrlen))) {
 279                 krb5_warn(contextp, rk_SOCK_ERRNO, "bind");
 280                 rk_closesocket(s);
 281                 continue;
 282             }
 283             if (rk_IS_SOCKET_ERROR(listen (s, SOMAXCONN))) {
 284                 krb5_warn(contextp, rk_SOCK_ERRNO, "listen");
 285                 rk_closesocket(s);
 286                 continue;
 287             }
 288
 289             socket_set_keepalive(s, 1);
 290             socks[num_socks++] = s;
 291         }
 292         freeaddrinfo (ai);
 293     }
 294     if(num_socks == 0)
 295         krb5_errx(contextp, 1, "no sockets to listen to - exiting");
 296
 297     roken_detach_finish(NULL, daemon_child);
 298
 299     wait_for_connection(contextp, socks, num_socks);
 300     free(socks);
 301 }