monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.17 2008/03/24 16:11:07 deraadt Exp $ */
   2 /*
   3  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
   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  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  *
  15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25  */
  26
  27 #include "includes.h"
  28
  29 #include <sys/types.h>
  30 #include <sys/socket.h>
  31 #include <sys/uio.h>
  32 #ifdef HAVE_SYS_UN_H
  33 #include <sys/un.h>
  34 #endif
  35
  36 #include <errno.h>
  37 #include <string.h>
  38 #include <stdarg.h>
  39
  40 #include "log.h"
  41 #include "monitor_fdpass.h"
  42
  43 int
  44 mm_send_fd(int sock, int fd)
  45 {
  46 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  47         struct msghdr msg;
  48         struct iovec vec;
  49         char ch = '\0';
  50         ssize_t n;
  51 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  52         union {
  53                 struct cmsghdr hdr;
  54                 char tmp[CMSG_SPACE(sizeof(int))];
  55                 char buf[CMSG_SPACE(sizeof(int))];
  56         } cmsgbuf;
  57         struct cmsghdr *cmsg;
  58 #endif
  59
  60         memset(&msg, 0, sizeof(msg));
  61 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  62         msg.msg_accrights = (caddr_t)&fd;
  63         msg.msg_accrightslen = sizeof(fd);
  64 #else
  65         msg.msg_control = (caddr_t)&cmsgbuf.buf;
  66         msg.msg_controllen = sizeof(cmsgbuf.buf);
  67         cmsg = CMSG_FIRSTHDR(&msg);
  68         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  69         cmsg->cmsg_level = SOL_SOCKET;
  70         cmsg->cmsg_type = SCM_RIGHTS;
  71         *(int *)CMSG_DATA(cmsg) = fd;
  72 #endif
  73
  74         vec.iov_base = &ch;
  75         vec.iov_len = 1;
  76         msg.msg_iov = &vec;
  77         msg.msg_iovlen = 1;
  78
  79         if ((n = sendmsg(sock, &msg, 0)) == -1) {
  80                 error("%s: sendmsg(%d): %s", __func__, fd,
  81                     strerror(errno));
  82                 return -1;
  83         }
  84
  85         if (n != 1) {
  86                 error("%s: sendmsg: expected sent 1 got %ld",
  87                     __func__, (long)n);
  88                 return -1;
  89         }
  90         return 0;
  91 #else
  92         error("%s: file descriptor passing not supported", __func__);
  93         return -1;
  94 #endif
  95 }
  96
  97 int
  98 mm_receive_fd(int sock)
  99 {
 100 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
 101         struct msghdr msg;
 102         struct iovec vec;
 103         ssize_t n;
 104         char ch;
 105         int fd;
 106 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
 107         union {
 108                 struct cmsghdr hdr;
 109                 char buf[CMSG_SPACE(sizeof(int))];
 110         } cmsgbuf;
 111         struct cmsghdr *cmsg;
 112 #endif
 113
 114         memset(&msg, 0, sizeof(msg));
 115         vec.iov_base = &ch;
 116         vec.iov_len = 1;
 117         msg.msg_iov = &vec;
 118         msg.msg_iovlen = 1;
 119 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 120         msg.msg_accrights = (caddr_t)&fd;
 121         msg.msg_accrightslen = sizeof(fd);
 122 #else
 123         msg.msg_control = &cmsgbuf.buf;
 124         msg.msg_controllen = sizeof(cmsgbuf.buf);
 125 #endif
 126
 127         if ((n = recvmsg(sock, &msg, 0)) == -1) {
 128                 error("%s: recvmsg: %s", __func__, strerror(errno));
 129                 return -1;
 130         }
 131         if (n != 1) {
 132                 error("%s: recvmsg: expected received 1 got %ld",
 133                     __func__, (long)n);
 134                 return -1;
 135         }
 136
 137 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 138         if (msg.msg_accrightslen != sizeof(fd)) {
 139                 error("%s: no fd", __func__);
 140                 return -1;
 141         }
 142 #else
 143         cmsg = CMSG_FIRSTHDR(&msg);
 144         if (cmsg == NULL) {
 145                 error("%s: no message header", __func__);
 146                 return -1;
 147         }
 148 #ifndef BROKEN_CMSG_TYPE
 149         if (cmsg->cmsg_type != SCM_RIGHTS) {
 150                 error("%s: expected type %d got %d", __func__,
 151                     SCM_RIGHTS, cmsg->cmsg_type);
 152                 return -1;
 153         }
 154 #endif
 155         fd = (*(int *)CMSG_DATA(cmsg));
 156 #endif
 157         return fd;
 158 #else
 159         error("%s: file descriptor passing not supported", __func__);
 160         return -1;
 161 #endif
 162 }