monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.11 2006/07/22 20:48:23 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 <errno.h>
  34 #include <string.h>
  35
  36 #include "log.h"
  37 #include "monitor_fdpass.h"
  38
  39 void
  40 mm_send_fd(int sock, int fd)
  41 {
  42 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  43         struct msghdr msg;
  44         struct iovec vec;
  45         char ch = '\0';
  46         ssize_t n;
  47 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  48         char tmp[CMSG_SPACE(sizeof(int))];
  49         struct cmsghdr *cmsg;
  50 #endif
  51
  52         memset(&msg, 0, sizeof(msg));
  53 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  54         msg.msg_accrights = (caddr_t)&fd;
  55         msg.msg_accrightslen = sizeof(fd);
  56 #else
  57         msg.msg_control = (caddr_t)tmp;
  58         msg.msg_controllen = CMSG_LEN(sizeof(int));
  59         cmsg = CMSG_FIRSTHDR(&msg);
  60         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  61         cmsg->cmsg_level = SOL_SOCKET;
  62         cmsg->cmsg_type = SCM_RIGHTS;
  63         *(int *)CMSG_DATA(cmsg) = fd;
  64 #endif
  65
  66         vec.iov_base = &ch;
  67         vec.iov_len = 1;
  68         msg.msg_iov = &vec;
  69         msg.msg_iovlen = 1;
  70
  71         if ((n = sendmsg(sock, &msg, 0)) == -1)
  72                 fatal("%s: sendmsg(%d): %s", __func__, fd,
  73                     strerror(errno));
  74         if (n != 1)
  75                 fatal("%s: sendmsg: expected sent 1 got %ld",
  76                     __func__, (long)n);
  77 #else
  78         fatal("%s: UsePrivilegeSeparation=yes not supported",
  79             __func__);
  80 #endif
  81 }
  82
  83 int
  84 mm_receive_fd(int sock)
  85 {
  86 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  87         struct msghdr msg;
  88         struct iovec vec;
  89         ssize_t n;
  90         char ch;
  91         int fd;
  92 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  93         char tmp[CMSG_SPACE(sizeof(int))];
  94         struct cmsghdr *cmsg;
  95 #endif
  96
  97         memset(&msg, 0, sizeof(msg));
  98         vec.iov_base = &ch;
  99         vec.iov_len = 1;
 100         msg.msg_iov = &vec;
 101         msg.msg_iovlen = 1;
 102 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 103         msg.msg_accrights = (caddr_t)&fd;
 104         msg.msg_accrightslen = sizeof(fd);
 105 #else
 106         msg.msg_control = tmp;
 107         msg.msg_controllen = sizeof(tmp);
 108 #endif
 109
 110         if ((n = recvmsg(sock, &msg, 0)) == -1)
 111                 fatal("%s: recvmsg: %s", __func__, strerror(errno));
 112         if (n != 1)
 113                 fatal("%s: recvmsg: expected received 1 got %ld",
 114                     __func__, (long)n);
 115
 116 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 117         if (msg.msg_accrightslen != sizeof(fd))
 118                 fatal("%s: no fd", __func__);
 119 #else
 120         cmsg = CMSG_FIRSTHDR(&msg);
 121         if (cmsg == NULL)
 122                 fatal("%s: no message header", __func__);
 123 #ifndef BROKEN_CMSG_TYPE
 124         if (cmsg->cmsg_type != SCM_RIGHTS)
 125                 fatal("%s: expected type %d got %d", __func__,
 126                     SCM_RIGHTS, cmsg->cmsg_type);
 127 #endif
 128         fd = (*(int *)CMSG_DATA(cmsg));
 129 #endif
 130         return fd;
 131 #else
 132         fatal("%s: UsePrivilegeSeparation=yes not supported",
 133             __func__);
 134 #endif
 135 }