crypto/dist/ssh/monitor_fdpass.c

   1 /*      $NetBSD: monitor_fdpass.c,v 1.7 2008/04/13 21:44:14 christos Exp $      */
   2 /* $OpenBSD: monitor_fdpass.c,v 1.17 2008/03/24 16:11:07 deraadt Exp $ */
   3 /*
   4  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
   5  * All rights reserved.
   6  *
   7  * Redistribution and use in source and binary forms, with or without
   8  * modification, are permitted provided that the following conditions
   9  * are met:
  10  * 1. Redistributions of source code must retain the above copyright
  11  *    notice, this list of conditions and the following disclaimer.
  12  * 2. Redistributions in binary form must reproduce the above copyright
  13  *    notice, this list of conditions and the following disclaimer in the
  14  *    documentation and/or other materials provided with the distribution.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  17  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  18  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  19  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  20  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  21  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  23  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  24  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  25  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  26  */
  27
  28 #include "includes.h"
  29 __RCSID("$NetBSD: monitor_fdpass.c,v 1.7 2008/04/13 21:44:14 christos Exp $");
  30 #include <sys/types.h>
  31 #include <sys/socket.h>
  32 #include <sys/uio.h>
  33
  34 #include <errno.h>
  35 #include <string.h>
  36 #include <stdarg.h>
  37
  38 #include "log.h"
  39 #include "monitor_fdpass.h"
  40
  41 int
  42 mm_send_fd(int sock, int fd)
  43 {
  44         struct msghdr msg;
  45         union {
  46                 struct cmsghdr hdr;
  47                 char buf[1024];
  48         } cmsgbuf;
  49         struct cmsghdr *cmsg;
  50         struct iovec vec;
  51         char ch = '\0';
  52         ssize_t n;
  53
  54         if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int))) {
  55                 error("%s: %zu < %zu, recompile", __func__,
  56                     sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
  57                 return -1;
  58         }
  59
  60         memset(&msg, 0, sizeof(msg));
  61         msg.msg_control = &cmsgbuf.buf;
  62         msg.msg_controllen = CMSG_SPACE(sizeof(int));
  63         cmsg = CMSG_FIRSTHDR(&msg);
  64         cmsg->cmsg_len = CMSG_LEN(sizeof(int));
  65         cmsg->cmsg_level = SOL_SOCKET;
  66         cmsg->cmsg_type = SCM_RIGHTS;
  67         *(int *)CMSG_DATA(cmsg) = fd;
  68         msg.msg_controllen = cmsg->cmsg_len;
  69
  70         vec.iov_base = &ch;
  71         vec.iov_len = 1;
  72         msg.msg_iov = &vec;
  73         msg.msg_iovlen = 1;
  74
  75         if ((n = sendmsg(sock, &msg, 0)) == -1) {
  76                 error("%s: sendmsg(%d): %s", __func__, fd,
  77                     strerror(errno));
  78                 return -1;
  79         }
  80
  81         if (n != 1) {
  82                 error("%s: sendmsg: expected sent 1 got %ld",
  83                     __func__, (long)n);
  84                 return -1;
  85         }
  86         return 0;
  87 }
  88
  89 int
  90 mm_receive_fd(int sock)
  91 {
  92         struct msghdr msg;
  93         union {
  94                 struct cmsghdr hdr;
  95                 char buf[1024];
  96         } cmsgbuf;
  97         struct cmsghdr *cmsg;
  98         struct iovec vec;
  99         ssize_t n;
 100         char ch;
 101         int fd;
 102
 103         if (sizeof(cmsgbuf.buf) < CMSG_SPACE(sizeof(int))) {
 104                 error("%s: %zu < %zu, recompile", __func__,
 105                     sizeof(cmsgbuf.buf), CMSG_SPACE(sizeof(int)));
 106                 return -1;
 107         }
 108
 109         memset(&msg, 0, sizeof(msg));
 110         vec.iov_base = &ch;
 111         vec.iov_len = 1;
 112         msg.msg_iov = &vec;
 113         msg.msg_iovlen = 1;
 114         msg.msg_control = &cmsgbuf.buf;
 115         msg.msg_controllen = CMSG_SPACE(sizeof(int));
 116
 117         if ((n = recvmsg(sock, &msg, 0)) == -1) {
 118                 error("%s: recvmsg: %s", __func__, strerror(errno));
 119                 return -1;
 120         }
 121
 122         if (n != 1) {
 123                 error("%s: recvmsg: expected received 1 got %ld",
 124                     __func__, (long)n);
 125                 return -1;
 126         }
 127
 128         cmsg = CMSG_FIRSTHDR(&msg);
 129         if (cmsg == NULL) {
 130                 error("%s: no message header", __func__);
 131                 return -1;
 132         }
 133
 134         if (cmsg->cmsg_type != SCM_RIGHTS) {
 135                 error("%s: expected type %d got %d", __func__,
 136                     SCM_RIGHTS, cmsg->cmsg_type);
 137                 return -1;
 138         }
 139         fd = (*(int *)CMSG_DATA(cmsg));
 140         return fd;
 141 }