1/*	$OpenBSD: privsep_fdpass.c,v 1.5 2008/03/24 16:11:08 deraadt Exp $	*/
2
3/*
4 * Copyright 2001 Niels Provos <provos@citi.umich.edu>
5 * All rights reserved.
6 *
7 * Copyright (c) 2002 Matthieu Herrb
8 * All rights reserved.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 *
14 *    - Redistributions of source code must retain the above copyright
15 *      notice, this list of conditions and the following disclaimer.
16 *    - Redistributions in binary form must reproduce the above
17 *      copyright notice, this list of conditions and the following
18 *      disclaimer in the documentation and/or other materials provided
19 *      with the distribution.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
29 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
31 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
32 * POSSIBILITY OF SUCH DAMAGE.
33 */
34#include <sys/param.h>
35#include <sys/uio.h>
36#include <sys/types.h>
37#include <sys/socket.h>
38#include <sys/stat.h>
39#include <err.h>
40#include <errno.h>
41#include <fcntl.h>
42#include <signal.h>
43#include <stdio.h>
44#include <stdlib.h>
45#include <string.h>
46#include <unistd.h>
47#include "pflogd.h"
48
49void
50send_fd(int sock, int fd)
51{
52	struct msghdr msg;
53	union {
54		struct cmsghdr hdr;
55		char buf[CMSG_SPACE(sizeof(int))];
56	} cmsgbuf;
57	struct cmsghdr *cmsg;
58	struct iovec vec;
59	int result = 0;
60	ssize_t n;
61
62	memset(&msg, 0, sizeof(msg));
63
64	if (fd >= 0) {
65		msg.msg_control = (caddr_t)&cmsgbuf.buf;
66		msg.msg_controllen = sizeof(cmsgbuf.buf);
67		cmsg = CMSG_FIRSTHDR(&msg);
68		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
69		cmsg->cmsg_level = SOL_SOCKET;
70		cmsg->cmsg_type = SCM_RIGHTS;
71		*(int *)CMSG_DATA(cmsg) = fd;
72	} else {
73		result = errno;
74	}
75
76	vec.iov_base = &result;
77	vec.iov_len = sizeof(int);
78	msg.msg_iov = &vec;
79	msg.msg_iovlen = 1;
80
81	if ((n = sendmsg(sock, &msg, 0)) == -1)
82		warn("%s: sendmsg(%d)", __func__, sock);
83	if (n != sizeof(int))
84		warnx("%s: sendmsg: expected sent 1 got %ld",
85		    __func__, (long)n);
86}
87
88int
89receive_fd(int sock)
90{
91	struct msghdr msg;
92	union {
93		struct cmsghdr hdr;
94		char buf[CMSG_SPACE(sizeof(int))];
95	} cmsgbuf;
96	struct cmsghdr *cmsg;
97	struct iovec vec;
98	ssize_t n;
99	int result;
100	int fd;
101
102	memset(&msg, 0, sizeof(msg));
103	vec.iov_base = &result;
104	vec.iov_len = sizeof(int);
105	msg.msg_iov = &vec;
106	msg.msg_iovlen = 1;
107	msg.msg_control = &cmsgbuf.buf;
108	msg.msg_controllen = sizeof(cmsgbuf.buf);
109
110	if ((n = recvmsg(sock, &msg, 0)) == -1)
111		warn("%s: recvmsg", __func__);
112	if (n != sizeof(int))
113		warnx("%s: recvmsg: expected received 1 got %ld",
114		    __func__, (long)n);
115	if (result == 0) {
116		cmsg = CMSG_FIRSTHDR(&msg);
117		if (cmsg == NULL) {
118			warnx("%s: no message header", __func__);
119			return -1;
120		}
121		if (cmsg->cmsg_type != SCM_RIGHTS)
122			warnx("%s: expected type %d got %d", __func__,
123			    SCM_RIGHTS, cmsg->cmsg_type);
124		fd = (*(int *)CMSG_DATA(cmsg));
125		return fd;
126	} else {
127		errno = result;
128		return -1;
129	}
130}
131