monitor_fdpass.c

   1 /*
   2  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  */
  25
  26 #include "includes.h"
  27 RCSID("$OpenBSD: monitor_fdpass.c,v 1.6 2004/08/13 02:51:48 djm Exp $");
  28
  29 #include <sys/uio.h>
  30
  31 #include "log.h"
  32 #include "monitor_fdpass.h"
  33
  34 void
  35 mm_send_fd(int sock, int fd)
  36 {
  37 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  38         struct msghdr msg;
  39         struct iovec vec;
  40         char ch = '\0';
  41         ssize_t n;
  42 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  43         char tmp[CMSG_SPACE(sizeof(int))];
  44         struct cmsghdr *cmsg;
  45 #endif
  46
  47         memset(&msg, 0, sizeof(msg));
  48 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  49         msg.msg_accrights = (caddr_t)&fd;
  50         msg.msg_accrightslen = sizeof(fd);
  51 #else
  52         msg.msg_control = (caddr_t)tmp;
  53         msg.msg_controllen = CMSG_LEN(sizeof(int));
  54         cmsg = CMSG_FIRSTHDR(&msg);
  55         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  56         cmsg->cmsg_level = SOL_SOCKET;
  57         cmsg->cmsg_type = SCM_RIGHTS;
  58         *(int *)CMSG_DATA(cmsg) = fd;
  59 #endif
  60
  61         vec.iov_base = &ch;
  62         vec.iov_len = 1;
  63         msg.msg_iov = &vec;
  64         msg.msg_iovlen = 1;
  65
  66         if ((n = sendmsg(sock, &msg, 0)) == -1)
  67                 fatal("%s: sendmsg(%d): %s", __func__, fd,
  68                     strerror(errno));
  69         if (n != 1)
  70                 fatal("%s: sendmsg: expected sent 1 got %ld",
  71                     __func__, (long)n);
  72 #else
  73         fatal("%s: UsePrivilegeSeparation=yes not supported",
  74             __func__);
  75 #endif
  76 }
  77
  78 int
  79 mm_receive_fd(int sock)
  80 {
  81 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  82         struct msghdr msg;
  83         struct iovec vec;
  84         ssize_t n;
  85         char ch;
  86         int fd;
  87 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  88         char tmp[CMSG_SPACE(sizeof(int))];
  89         struct cmsghdr *cmsg;
  90 #endif
  91
  92         memset(&msg, 0, sizeof(msg));
  93         vec.iov_base = &ch;
  94         vec.iov_len = 1;
  95         msg.msg_iov = &vec;
  96         msg.msg_iovlen = 1;
  97 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  98         msg.msg_accrights = (caddr_t)&fd;
  99         msg.msg_accrightslen = sizeof(fd);
 100 #else
 101         msg.msg_control = tmp;
 102         msg.msg_controllen = sizeof(tmp);
 103 #endif
 104
 105         if ((n = recvmsg(sock, &msg, 0)) == -1)
 106                 fatal("%s: recvmsg: %s", __func__, strerror(errno));
 107         if (n != 1)
 108                 fatal("%s: recvmsg: expected received 1 got %ld",
 109                     __func__, (long)n);
 110
 111 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 112         if (msg.msg_accrightslen != sizeof(fd))
 113                 fatal("%s: no fd", __func__);
 114 #else
 115         cmsg = CMSG_FIRSTHDR(&msg);
 116         if (cmsg == NULL)
 117                 fatal("%s: no message header", __func__);
 118 #ifndef BROKEN_CMSG_TYPE
 119         if (cmsg->cmsg_type != SCM_RIGHTS)
 120                 fatal("%s: expected type %d got %d", __func__,
 121                     SCM_RIGHTS, cmsg->cmsg_type);
 122 #endif
 123         fd = (*(int *)CMSG_DATA(cmsg));
 124 #endif
 125         return fd;
 126 #else
 127         fatal("%s: UsePrivilegeSeparation=yes not supported",
 128             __func__);
 129 #endif
 130 }