monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.9 2006/07/08 21:47:12 stevesk 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
  33 #include "log.h"
  34 #include "monitor_fdpass.h"
  35
  36 void
  37 mm_send_fd(int sock, int fd)
  38 {
  39 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  40         struct msghdr msg;
  41         struct iovec vec;
  42         char ch = '\0';
  43         ssize_t n;
  44 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  45         char tmp[CMSG_SPACE(sizeof(int))];
  46         struct cmsghdr *cmsg;
  47 #endif
  48
  49         memset(&msg, 0, sizeof(msg));
  50 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  51         msg.msg_accrights = (caddr_t)&fd;
  52         msg.msg_accrightslen = sizeof(fd);
  53 #else
  54         msg.msg_control = (caddr_t)tmp;
  55         msg.msg_controllen = CMSG_LEN(sizeof(int));
  56         cmsg = CMSG_FIRSTHDR(&msg);
  57         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  58         cmsg->cmsg_level = SOL_SOCKET;
  59         cmsg->cmsg_type = SCM_RIGHTS;
  60         *(int *)CMSG_DATA(cmsg) = fd;
  61 #endif
  62
  63         vec.iov_base = &ch;
  64         vec.iov_len = 1;
  65         msg.msg_iov = &vec;
  66         msg.msg_iovlen = 1;
  67
  68         if ((n = sendmsg(sock, &msg, 0)) == -1)
  69                 fatal("%s: sendmsg(%d): %s", __func__, fd,
  70                     strerror(errno));
  71         if (n != 1)
  72                 fatal("%s: sendmsg: expected sent 1 got %ld",
  73                     __func__, (long)n);
  74 #else
  75         fatal("%s: UsePrivilegeSeparation=yes not supported",
  76             __func__);
  77 #endif
  78 }
  79
  80 int
  81 mm_receive_fd(int sock)
  82 {
  83 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  84         struct msghdr msg;
  85         struct iovec vec;
  86         ssize_t n;
  87         char ch;
  88         int fd;
  89 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  90         char tmp[CMSG_SPACE(sizeof(int))];
  91         struct cmsghdr *cmsg;
  92 #endif
  93
  94         memset(&msg, 0, sizeof(msg));
  95         vec.iov_base = &ch;
  96         vec.iov_len = 1;
  97         msg.msg_iov = &vec;
  98         msg.msg_iovlen = 1;
  99 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 100         msg.msg_accrights = (caddr_t)&fd;
 101         msg.msg_accrightslen = sizeof(fd);
 102 #else
 103         msg.msg_control = tmp;
 104         msg.msg_controllen = sizeof(tmp);
 105 #endif
 106
 107         if ((n = recvmsg(sock, &msg, 0)) == -1)
 108                 fatal("%s: recvmsg: %s", __func__, strerror(errno));
 109         if (n != 1)
 110                 fatal("%s: recvmsg: expected received 1 got %ld",
 111                     __func__, (long)n);
 112
 113 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 114         if (msg.msg_accrightslen != sizeof(fd))
 115                 fatal("%s: no fd", __func__);
 116 #else
 117         cmsg = CMSG_FIRSTHDR(&msg);
 118         if (cmsg == NULL)
 119                 fatal("%s: no message header", __func__);
 120 #ifndef BROKEN_CMSG_TYPE
 121         if (cmsg->cmsg_type != SCM_RIGHTS)
 122                 fatal("%s: expected type %d got %d", __func__,
 123                     SCM_RIGHTS, cmsg->cmsg_type);
 124 #endif
 125         fd = (*(int *)CMSG_DATA(cmsg));
 126 #endif
 127         return fd;
 128 #else
 129         fatal("%s: UsePrivilegeSeparation=yes not supported",
 130             __func__);
 131 #endif
 132 }