xref: /freebsd/contrib/pf/pflogd/privsep_fdpass.c (revision 39beb93c3f8bdbf72a61fda42300b5ebed7390c8)
1 /*	$OpenBSD: privsep_fdpass.c,v 1.2 2004/08/13 02:51:48 djm 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 
49 void
50 send_fd(int sock, int fd)
51 {
52 	struct msghdr msg;
53 	char tmp[CMSG_SPACE(sizeof(int))];
54 	struct cmsghdr *cmsg;
55 	struct iovec vec;
56 	int result = 0;
57 	ssize_t n;
58 
59 	memset(&msg, 0, sizeof(msg));
60 
61 	if (fd >= 0) {
62 		msg.msg_control = (caddr_t)tmp;
63 		msg.msg_controllen = CMSG_LEN(sizeof(int));
64 		cmsg = CMSG_FIRSTHDR(&msg);
65 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
66 		cmsg->cmsg_level = SOL_SOCKET;
67 		cmsg->cmsg_type = SCM_RIGHTS;
68 		*(int *)CMSG_DATA(cmsg) = fd;
69 	} else {
70 		result = errno;
71 	}
72 
73 	vec.iov_base = &result;
74 	vec.iov_len = sizeof(int);
75 	msg.msg_iov = &vec;
76 	msg.msg_iovlen = 1;
77 
78 	if ((n = sendmsg(sock, &msg, 0)) == -1)
79 		warn("%s: sendmsg(%d)", __func__, sock);
80 	if (n != sizeof(int))
81 		warnx("%s: sendmsg: expected sent 1 got %ld",
82 		    __func__, (long)n);
83 }
84 
85 int
86 receive_fd(int sock)
87 {
88 	struct msghdr msg;
89 	char tmp[CMSG_SPACE(sizeof(int))];
90 	struct cmsghdr *cmsg;
91 	struct iovec vec;
92 	ssize_t n;
93 	int result;
94 	int fd;
95 
96 	memset(&msg, 0, sizeof(msg));
97 	vec.iov_base = &result;
98 	vec.iov_len = sizeof(int);
99 	msg.msg_iov = &vec;
100 	msg.msg_iovlen = 1;
101 	msg.msg_control = tmp;
102 	msg.msg_controllen = sizeof(tmp);
103 
104 	if ((n = recvmsg(sock, &msg, 0)) == -1)
105 		warn("%s: recvmsg", __func__);
106 	if (n != sizeof(int))
107 		warnx("%s: recvmsg: expected received 1 got %ld",
108 		    __func__, (long)n);
109 	if (result == 0) {
110 		cmsg = CMSG_FIRSTHDR(&msg);
111 		if (cmsg == NULL) {
112 			warnx("%s: no message header", __func__);
113 			return -1;
114 		}
115 		if (cmsg->cmsg_type != SCM_RIGHTS)
116 			warnx("%s: expected type %d got %d", __func__,
117 			    SCM_RIGHTS, cmsg->cmsg_type);
118 		fd = (*(int *)CMSG_DATA(cmsg));
119 		return fd;
120 	} else {
121 		errno = result;
122 		return -1;
123 	}
124 }
125