xref: /openbsd/usr.bin/ssh/msg.c (revision 097a140d)
1 /* $OpenBSD: msg.c,v 1.20 2020/10/18 11:32:01 djm Exp $ */
2 /*
3  * Copyright (c) 2002 Markus Friedl.  All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/types.h>
27 #include <sys/uio.h>
28 
29 #include <errno.h>
30 #include <stdio.h>
31 #include <string.h>
32 #include <unistd.h>
33 #include <stdarg.h>
34 
35 #include "sshbuf.h"
36 #include "ssherr.h"
37 #include "log.h"
38 #include "atomicio.h"
39 #include "msg.h"
40 #include "misc.h"
41 
42 int
43 ssh_msg_send(int fd, u_char type, struct sshbuf *m)
44 {
45 	u_char buf[5];
46 	u_int mlen = sshbuf_len(m);
47 
48 	debug3_f("type %u", (unsigned int)type & 0xff);
49 
50 	put_u32(buf, mlen + 1);
51 	buf[4] = type;		/* 1st byte of payload is mesg-type */
52 	if (atomicio(vwrite, fd, buf, sizeof(buf)) != sizeof(buf)) {
53 		error_f("write: %s", strerror(errno));
54 		return (-1);
55 	}
56 	if (atomicio(vwrite, fd, sshbuf_mutable_ptr(m), mlen) != mlen) {
57 		error_f("write: %s", strerror(errno));
58 		return (-1);
59 	}
60 	return (0);
61 }
62 
63 int
64 ssh_msg_recv(int fd, struct sshbuf *m)
65 {
66 	u_char buf[4], *p;
67 	u_int msg_len;
68 	int r;
69 
70 	debug3("ssh_msg_recv entering");
71 
72 	if (atomicio(read, fd, buf, sizeof(buf)) != sizeof(buf)) {
73 		if (errno != EPIPE)
74 			error_f("read header: %s", strerror(errno));
75 		return (-1);
76 	}
77 	msg_len = get_u32(buf);
78 	if (msg_len > sshbuf_max_size(m)) {
79 		error_f("read: bad msg_len %u", msg_len);
80 		return (-1);
81 	}
82 	sshbuf_reset(m);
83 	if ((r = sshbuf_reserve(m, msg_len, &p)) != 0) {
84 		error_fr(r, "reserve");
85 		return -1;
86 	}
87 	if (atomicio(read, fd, p, msg_len) != msg_len) {
88 		error_f("read: %s", strerror(errno));
89 		return (-1);
90 	}
91 	return (0);
92 }
93