monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.10 2006/07/11 20:07:25 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
  35 #include "log.h"
  36 #include "monitor_fdpass.h"
  37
  38 void
  39 mm_send_fd(int sock, int fd)
  40 {
  41 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  42         struct msghdr msg;
  43         struct iovec vec;
  44         char ch = '\0';
  45         ssize_t n;
  46 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  47         char tmp[CMSG_SPACE(sizeof(int))];
  48         struct cmsghdr *cmsg;
  49 #endif
  50
  51         memset(&msg, 0, sizeof(msg));
  52 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  53         msg.msg_accrights = (caddr_t)&fd;
  54         msg.msg_accrightslen = sizeof(fd);
  55 #else
  56         msg.msg_control = (caddr_t)tmp;
  57         msg.msg_controllen = CMSG_LEN(sizeof(int));
  58         cmsg = CMSG_FIRSTHDR(&msg);
  59         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  60         cmsg->cmsg_level = SOL_SOCKET;
  61         cmsg->cmsg_type = SCM_RIGHTS;
  62         *(int *)CMSG_DATA(cmsg) = fd;
  63 #endif
  64
  65         vec.iov_base = &ch;
  66         vec.iov_len = 1;
  67         msg.msg_iov = &vec;
  68         msg.msg_iovlen = 1;
  69
  70         if ((n = sendmsg(sock, &msg, 0)) == -1)
  71                 fatal("%s: sendmsg(%d): %s", __func__, fd,
  72                     strerror(errno));
  73         if (n != 1)
  74                 fatal("%s: sendmsg: expected sent 1 got %ld",
  75                     __func__, (long)n);
  76 #else
  77         fatal("%s: UsePrivilegeSeparation=yes not supported",
  78             __func__);
  79 #endif
  80 }
  81
  82 int
  83 mm_receive_fd(int sock)
  84 {
  85 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  86         struct msghdr msg;
  87         struct iovec vec;
  88         ssize_t n;
  89         char ch;
  90         int fd;
  91 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  92         char tmp[CMSG_SPACE(sizeof(int))];
  93         struct cmsghdr *cmsg;
  94 #endif
  95
  96         memset(&msg, 0, sizeof(msg));
  97         vec.iov_base = &ch;
  98         vec.iov_len = 1;
  99         msg.msg_iov = &vec;
 100         msg.msg_iovlen = 1;
 101 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 102         msg.msg_accrights = (caddr_t)&fd;
 103         msg.msg_accrightslen = sizeof(fd);
 104 #else
 105         msg.msg_control = tmp;
 106         msg.msg_controllen = sizeof(tmp);
 107 #endif
 108
 109         if ((n = recvmsg(sock, &msg, 0)) == -1)
 110                 fatal("%s: recvmsg: %s", __func__, strerror(errno));
 111         if (n != 1)
 112                 fatal("%s: recvmsg: expected received 1 got %ld",
 113                     __func__, (long)n);
 114
 115 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 116         if (msg.msg_accrightslen != sizeof(fd))
 117                 fatal("%s: no fd", __func__);
 118 #else
 119         cmsg = CMSG_FIRSTHDR(&msg);
 120         if (cmsg == NULL)
 121                 fatal("%s: no message header", __func__);
 122 #ifndef BROKEN_CMSG_TYPE
 123         if (cmsg->cmsg_type != SCM_RIGHTS)
 124                 fatal("%s: expected type %d got %d", __func__,
 125                     SCM_RIGHTS, cmsg->cmsg_type);
 126 #endif
 127         fd = (*(int *)CMSG_DATA(cmsg));
 128 #endif
 129         return fd;
 130 #else
 131         fatal("%s: UsePrivilegeSeparation=yes not supported",
 132             __func__);
 133 #endif
 134 }