1 /*	$OpenBSD: privsep_fdpass.c,v 1.1 2003/10/22 18:51:55 canacar Exp $	*/
2 /*	$DragonFly: src/usr.sbin/pflogd/privsep_fdpass.c,v 1.1 2004/09/21 21:25:28 joerg Exp $ */
3 
4 /*
5  * Copyright 2001 Niels Provos <provos@citi.umich.edu>
6  * All rights reserved.
7  *
8  * Copyright (c) 2002 Matthieu Herrb
9  * All rights reserved.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  *
15  *    - Redistributions of source code must retain the above copyright
16  *      notice, this list of conditions and the following disclaimer.
17  *    - Redistributions in binary form must reproduce the above
18  *      copyright notice, this list of conditions and the following
19  *      disclaimer in the documentation and/or other materials provided
20  *      with the distribution.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
23  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
27  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
30  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
32  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
33  * POSSIBILITY OF SUCH DAMAGE.
34  */
35 #include <sys/param.h>
36 #include <sys/uio.h>
37 #include <sys/types.h>
38 #include <sys/socket.h>
39 #include <sys/stat.h>
40 #include <err.h>
41 #include <errno.h>
42 #include <fcntl.h>
43 #include <signal.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #include <unistd.h>
48 #include "pflogd.h"
49 
50 void
51 send_fd(int sock, int fd)
52 {
53 	struct msghdr msg;
54 	char tmp[CMSG_SPACE(sizeof(int))];
55 	struct cmsghdr *cmsg;
56 	struct iovec vec;
57 	int result = 0;
58 	ssize_t n;
59 
60 	memset(&msg, 0, sizeof(msg));
61 
62 	if (fd >= 0) {
63 		msg.msg_control = (caddr_t)tmp;
64 		msg.msg_controllen = CMSG_LEN(sizeof(int));
65 		cmsg = CMSG_FIRSTHDR(&msg);
66 		cmsg->cmsg_len = CMSG_LEN(sizeof(int));
67 		cmsg->cmsg_level = SOL_SOCKET;
68 		cmsg->cmsg_type = SCM_RIGHTS;
69 		*(int *)CMSG_DATA(cmsg) = fd;
70 	} else {
71 		result = errno;
72 	}
73 
74 	vec.iov_base = (caddr_t)&result;
75 	vec.iov_len = sizeof(int);
76 	msg.msg_iov = &vec;
77 	msg.msg_iovlen = 1;
78 
79 	if ((n = sendmsg(sock, &msg, 0)) == -1)
80 		warn("%s: sendmsg(%d)", __func__, sock);
81 	if (n != sizeof(int))
82 		warnx("%s: sendmsg: expected sent 1 got %ld",
83 		    __func__, (long)n);
84 }
85 
86 int
87 receive_fd(int sock)
88 {
89 	struct msghdr msg;
90 	char tmp[CMSG_SPACE(sizeof(int))];
91 	struct cmsghdr *cmsg;
92 	struct iovec vec;
93 	ssize_t n;
94 	int result;
95 	int fd;
96 
97 	memset(&msg, 0, sizeof(msg));
98 	vec.iov_base = (caddr_t)&result;
99 	vec.iov_len = sizeof(int);
100 	msg.msg_iov = &vec;
101 	msg.msg_iovlen = 1;
102 	msg.msg_control = tmp;
103 	msg.msg_controllen = sizeof(tmp);
104 
105 	if ((n = recvmsg(sock, &msg, 0)) == -1)
106 		warn("%s: recvmsg", __func__);
107 	if (n != sizeof(int))
108 		warnx("%s: recvmsg: expected received 1 got %ld",
109 		    __func__, (long)n);
110 	if (result == 0) {
111 		cmsg = CMSG_FIRSTHDR(&msg);
112 		if (cmsg->cmsg_type != SCM_RIGHTS)
113 			warnx("%s: expected type %d got %d", __func__,
114 			    SCM_RIGHTS, cmsg->cmsg_type);
115 		fd = (*(int *)CMSG_DATA(cmsg));
116 		return fd;
117 	} else {
118 		errno = result;
119 		return -1;
120 	}
121 }
122