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 contextp, const char *service, unsigned int port)
  47 {
  48     struct kadm_port *p;
  49     p = malloc(sizeof(*p));
  50     if(p == NULL) {
  51         krb5_warnx(contextp, "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 contextp)
  65 {
  66     add_kadm_port(contextp, "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 contextp, 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(contextp);
  83         else
  84             add_kadm_port(contextp, 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     /*
  96      * waitpid() is async safe. will return -1 or 0 on no more zombie
  97      * children
  98      */
  99     while ((waitpid(-1, &status, WNOHANG)) > 0)
 100         ;
 101     SIGRETURN(0);
 102 }
 103
 104 static RETSIGTYPE
 105 terminate(int sig)
 106 {
 107     if(getpid() == pgrp) {
 108         /* parent */
 109         term_flag = 1;
 110         signal(sig, SIG_IGN);
 111         killpg(pgrp, sig);
 112     } else {
 113         /* child */
 114         if(doing_useful_work)
 115             term_flag = 1;
 116         else
 117             exit(0);
 118     }
 119     SIGRETURN(0);
 120 }
 121
 122 static int
 123 spawn_child(krb5_context contextp, int *socks,
 124             unsigned int num_socks, int this_sock)
 125 {
 126     int e;
 127     size_t i;
 128     struct sockaddr_storage __ss;
 129     struct sockaddr *sa = (struct sockaddr *)&__ss;
 130     socklen_t sa_size = sizeof(__ss);
 131     krb5_socket_t s;
 132     pid_t pid;
 133     krb5_address addr;
 134     char buf[128];
 135     size_t buf_len;
 136
 137     s = accept(socks[this_sock], sa, &sa_size);
 138     if(rk_IS_BAD_SOCKET(s)) {
 139         krb5_warn(contextp, rk_SOCK_ERRNO, "accept");
 140         return 1;
 141     }
 142     e = krb5_sockaddr2address(contextp, sa, &addr);
 143     if(e)
 144         krb5_warn(contextp, e, "krb5_sockaddr2address");
 145     else {
 146         e = krb5_print_address (&addr, buf, sizeof(buf),
 147                                 &buf_len);
 148         if(e)
 149             krb5_warn(contextp, e, "krb5_print_address");
 150         else
 151             krb5_warnx(contextp, "connection from %s", buf);
 152         krb5_free_address(contextp, &addr);
 153     }
 154
 155     pid = fork();
 156     if(pid == 0) {
 157         for(i = 0; i < num_socks; i++)
 158             rk_closesocket(socks[i]);
 159         dup2(s, STDIN_FILENO);
 160         dup2(s, STDOUT_FILENO);
 161         if(s != STDIN_FILENO && s != STDOUT_FILENO)
 162             rk_closesocket(s);
 163         return 0;
 164     } else {
 165         rk_closesocket(s);
 166     }
 167     return 1;
 168 }
 169
 170 static void
 171 wait_for_connection(krb5_context contextp,
 172                     krb5_socket_t *socks, unsigned int num_socks)
 173 {
 174     unsigned int i;
 175     int e;
 176     fd_set orig_read_set, read_set;
 177     int status, max_fd = -1;
 178
 179     FD_ZERO(&orig_read_set);
 180
 181     for(i = 0; i < num_socks; i++) {
 182 #ifdef FD_SETSIZE
 183         if (socks[i] >= FD_SETSIZE)
 184             errx (1, "fd too large");
 185 #endif
 186         FD_SET(socks[i], &orig_read_set);
 187         max_fd = max(max_fd, socks[i]);
 188     }
 189
 190     pgrp = getpid();
 191
 192     /* systemd may cause setpgid to fail with EPERM */
 193     if(setpgid(0, pgrp) < 0 && errno != EPERM)
 194         err(1, "setpgid");
 195
 196     signal(SIGTERM, terminate);
 197     signal(SIGINT, terminate);
 198     signal(SIGCHLD, sigchld);
 199
 200     while (term_flag == 0) {
 201         read_set = orig_read_set;
 202         e = select(max_fd + 1, &read_set, NULL, NULL, NULL);
 203         if(rk_IS_SOCKET_ERROR(e)) {
 204             if(rk_SOCK_ERRNO != EINTR)
 205                 krb5_warn(contextp, rk_SOCK_ERRNO, "select");
 206         } else if(e == 0)
 207             krb5_warnx(contextp, "select returned 0");
 208         else {
 209             for(i = 0; i < num_socks; i++) {
 210                 if(FD_ISSET(socks[i], &read_set))
 211                     if(spawn_child(contextp, socks, num_socks, i) == 0)
 212                         return;
 213             }
 214         }
 215     }
 216     signal(SIGCHLD, SIG_IGN);
 217
 218     while ((waitpid(-1, &status, WNOHANG)) > 0)
 219         ;
 220
 221     exit(0);
 222 }
 223
 224
 225 void
 226 start_server(krb5_context contextp, const char *port_str)
 227 {
 228     int e;
 229     struct kadm_port *p;
 230
 231     krb5_socket_t *socks = NULL, *tmp;
 232     unsigned int num_socks = 0;
 233     int i;
 234
 235     if (port_str == NULL)
 236         port_str = "+";
 237
 238     parse_ports(contextp, port_str);
 239
 240     for(p = kadm_ports; p; p = p->next) {
 241         struct addrinfo hints, *ai, *ap;
 242         char portstr[32];
 243         memset (&hints, 0, sizeof(hints));
 244         hints.ai_flags    = AI_PASSIVE;
 245         hints.ai_socktype = SOCK_STREAM;
 246
 247         e = getaddrinfo(NULL, p->port, &hints, &ai);
 248         if(e) {
 249             snprintf(portstr, sizeof(portstr), "%u", p->def_port);
 250             e = getaddrinfo(NULL, portstr, &hints, &ai);
 251         }
 252
 253         if(e) {
 254             krb5_warn(contextp, krb5_eai_to_heim_errno(e, errno),
 255                       "%s", portstr);
 256             continue;
 257         }
 258         i = 0;
 259         for(ap = ai; ap; ap = ap->ai_next)
 260             i++;
 261         tmp = realloc(socks, (num_socks + i) * sizeof(*socks));
 262         if(tmp == NULL) {
 263             krb5_warnx(contextp, "failed to reallocate %lu bytes",
 264                        (unsigned long)(num_socks + i) * sizeof(*socks));
 265             continue;
 266         }
 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             socks[num_socks++] = s;
 289         }
 290         freeaddrinfo (ai);
 291     }
 292     if(num_socks == 0)
 293         krb5_errx(contextp, 1, "no sockets to listen to - exiting");
 294
 295     wait_for_connection(contextp, socks, num_socks);
 296 }