1 /* $OpenBSD: monitor_fdpass.c,v 1.18 2008/11/30 11:59:26 dtucker 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 <sys/types.h>
28 #include <sys/socket.h>
29 #include <sys/uio.h>
30 
31 #include <errno.h>
32 #include <string.h>
33 #include <stdarg.h>
34 
35 #include "log.h"
36 #include "monitor_fdpass.h"
37 
38 __RCSID("$MirOS: src/usr.bin/ssh/monitor_fdpass.c,v 1.4 2009/10/04 16:35:25 tg Exp $");
39 
40 int
mm_send_fd(int sock,int fd)41 mm_send_fd(int sock, int fd)
42 {
43 	struct msghdr msg;
44 	union {
45 		struct cmsghdr hdr;
46 		char buf[CMSG_SPACE(sizeof(int))];
47 	} cmsgbuf;
48 	struct cmsghdr *cmsg;
49 	struct iovec vec;
50 	char ch = '\0';
51 	ssize_t n;
52 
53 	memset(&msg, 0, sizeof(msg));
54 	msg.msg_control = (caddr_t)&cmsgbuf.buf;
55 	msg.msg_controllen = CMSG_LEN(sizeof(int));
56 	cmsg = CMSG_FIRSTHDR(&msg);
57 	cmsg->cmsg_len = CMSG_LEN(sizeof(int));
58 	cmsg->cmsg_level = SOL_SOCKET;
59 	cmsg->cmsg_type = SCM_RIGHTS;
60 	memcpy(CMSG_DATA(cmsg), &fd, sizeof(fd));
61 
62 	vec.iov_base = &ch;
63 	vec.iov_len = 1;
64 	msg.msg_iov = &vec;
65 	msg.msg_iovlen = 1;
66 
67 	while ((n = sendmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
68 	    errno == EINTR))
69 		debug3("%s: sendmsg(%d): %s", __func__, fd, strerror(errno));
70 	if (n == -1) {
71 		error("%s: sendmsg(%d): %s", __func__, fd,
72 		    strerror(errno));
73 		return -1;
74 	}
75 
76 	if (n != 1) {
77 		error("%s: sendmsg: expected sent 1 got %ld",
78 		    __func__, (long)n);
79 		return -1;
80 	}
81 	return 0;
82 }
83 
84 int
mm_receive_fd(int sock)85 mm_receive_fd(int sock)
86 {
87 	struct msghdr msg;
88 	union {
89 		struct cmsghdr hdr;
90 		char buf[CMSG_SPACE(sizeof(int))];
91 	} cmsgbuf;
92 	struct cmsghdr *cmsg;
93 	struct iovec vec;
94 	ssize_t n;
95 	char ch;
96 	int fd;
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 	msg.msg_control = &cmsgbuf.buf;
104 	msg.msg_controllen = CMSG_LEN(sizeof(int));
105 
106 	while ((n = recvmsg(sock, &msg, 0)) == -1 && (errno == EAGAIN ||
107 	    errno == EINTR))
108 		debug3("%s: recvmsg: %s", __func__, strerror(errno));
109 	if (n == -1) {
110 		error("%s: recvmsg: %s", __func__, strerror(errno));
111 		return -1;
112 	}
113 
114 	if (n != 1) {
115 		error("%s: recvmsg: expected received 1 got %ld",
116 		    __func__, (long)n);
117 		return -1;
118 	}
119 
120 	cmsg = CMSG_FIRSTHDR(&msg);
121 	if (cmsg == NULL) {
122 		error("%s: no message header", __func__);
123 		return -1;
124 	}
125 
126 	if (cmsg->cmsg_type != SCM_RIGHTS) {
127 		error("%s: expected type %d got %d", __func__,
128 		    SCM_RIGHTS, cmsg->cmsg_type);
129 		return -1;
130 	}
131 	memcpy(&fd, CMSG_DATA(cmsg), sizeof(fd));
132 	return fd;
133 }
134