monitor_fdpass.c

   1 /* $OpenBSD: monitor_fdpass.c,v 1.12 2006/08/03 03:34:42 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
  33 #include <errno.h>
  34 #include <string.h>
  35 #include <stdarg.h>
  36
  37 #include "log.h"
  38 #include "monitor_fdpass.h"
  39
  40 void
  41 mm_send_fd(int sock, int fd)
  42 {
  43 #if defined(HAVE_SENDMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  44         struct msghdr msg;
  45         struct iovec vec;
  46         char ch = '\0';
  47         ssize_t n;
  48 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  49         char tmp[CMSG_SPACE(sizeof(int))];
  50         struct cmsghdr *cmsg;
  51 #endif
  52
  53         memset(&msg, 0, sizeof(msg));
  54 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
  55         msg.msg_accrights = (caddr_t)&fd;
  56         msg.msg_accrightslen = sizeof(fd);
  57 #else
  58         msg.msg_control = (caddr_t)tmp;
  59         msg.msg_controllen = CMSG_LEN(sizeof(int));
  60         cmsg = CMSG_FIRSTHDR(&msg);
  61         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  62         cmsg->cmsg_level = SOL_SOCKET;
  63         cmsg->cmsg_type = SCM_RIGHTS;
  64         *(int *)CMSG_DATA(cmsg) = fd;
  65 #endif
  66
  67         vec.iov_base = &ch;
  68         vec.iov_len = 1;
  69         msg.msg_iov = &vec;
  70         msg.msg_iovlen = 1;
  71
  72         if ((n = sendmsg(sock, &msg, 0)) == -1)
  73                 fatal("%s: sendmsg(%d): %s", __func__, fd,
  74                     strerror(errno));
  75         if (n != 1)
  76                 fatal("%s: sendmsg: expected sent 1 got %ld",
  77                     __func__, (long)n);
  78 #else
  79         fatal("%s: UsePrivilegeSeparation=yes not supported",
  80             __func__);
  81 #endif
  82 }
  83
  84 int
  85 mm_receive_fd(int sock)
  86 {
  87 #if defined(HAVE_RECVMSG) && (defined(HAVE_ACCRIGHTS_IN_MSGHDR) || defined(HAVE_CONTROL_IN_MSGHDR))
  88         struct msghdr msg;
  89         struct iovec vec;
  90         ssize_t n;
  91         char ch;
  92         int fd;
  93 #ifndef HAVE_ACCRIGHTS_IN_MSGHDR
  94         char tmp[CMSG_SPACE(sizeof(int))];
  95         struct cmsghdr *cmsg;
  96 #endif
  97
  98         memset(&msg, 0, sizeof(msg));
  99         vec.iov_base = &ch;
 100         vec.iov_len = 1;
 101         msg.msg_iov = &vec;
 102         msg.msg_iovlen = 1;
 103 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 104         msg.msg_accrights = (caddr_t)&fd;
 105         msg.msg_accrightslen = sizeof(fd);
 106 #else
 107         msg.msg_control = tmp;
 108         msg.msg_controllen = sizeof(tmp);
 109 #endif
 110
 111         if ((n = recvmsg(sock, &msg, 0)) == -1)
 112                 fatal("%s: recvmsg: %s", __func__, strerror(errno));
 113         if (n != 1)
 114                 fatal("%s: recvmsg: expected received 1 got %ld",
 115                     __func__, (long)n);
 116
 117 #ifdef HAVE_ACCRIGHTS_IN_MSGHDR
 118         if (msg.msg_accrightslen != sizeof(fd))
 119                 fatal("%s: no fd", __func__);
 120 #else
 121         cmsg = CMSG_FIRSTHDR(&msg);
 122         if (cmsg == NULL)
 123                 fatal("%s: no message header", __func__);
 124 #ifndef BROKEN_CMSG_TYPE
 125         if (cmsg->cmsg_type != SCM_RIGHTS)
 126                 fatal("%s: expected type %d got %d", __func__,
 127                     SCM_RIGHTS, cmsg->cmsg_type);
 128 #endif
 129         fd = (*(int *)CMSG_DATA(cmsg));
 130 #endif
 131         return fd;
 132 #else
 133         fatal("%s: UsePrivilegeSeparation=yes not supported",
 134             __func__);
 135 #endif
 136 }