compat.c revision 255767 
1/* $OpenBSD: compat.c,v 1.81 2013/05/17 00:13:13 djm Exp $ */
2/* $FreeBSD: head/crypto/openssh/compat.c 255767 2013-09-21 21:36:09Z des $ */
3/*
4 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  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 "includes.h"
28
29#include <sys/types.h>
30
31#include <stdlib.h>
32#include <string.h>
33#include <stdarg.h>
34
35#include "xmalloc.h"
36#include "buffer.h"
37#include "packet.h"
38#include "compat.h"
39#include "log.h"
40#include "match.h"
41
42int compat13 = 0;
43int compat20 = 0;
44int datafellows = 0;
45
46void
47enable_compat20(void)
48{
49	if (compat20)
50		return;
51	debug("Enabling compatibility mode for protocol 2.0");
52	compat20 = 1;
53}
54void
55enable_compat13(void)
56{
57	debug("Enabling compatibility mode for protocol 1.3");
58	compat13 = 1;
59}
60/* datafellows bug compatibility */
61void
62compat_datafellows(const char *version)
63{
64	int i;
65	static struct {
66		char	*pat;
67		int	bugs;
68	} check[] = {
69		{ "OpenSSH-2.0*,"
70		  "OpenSSH-2.1*,"
71		  "OpenSSH_2.1*,"
72		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
73					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
74					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
75		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
76					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
77					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
78		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
79					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
80					SSH_OLD_FORWARD_ADDR},
81		{ "OpenSSH_2.5.0p1*,"
82		  "OpenSSH_2.5.1p1*",
83					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
84					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
85					SSH_OLD_FORWARD_ADDR},
86		{ "OpenSSH_2.5.0*,"
87		  "OpenSSH_2.5.1*,"
88		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
89					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
90		{ "OpenSSH_2.5.3*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
91					SSH_OLD_FORWARD_ADDR},
92		{ "OpenSSH_2.*,"
93		  "OpenSSH_3.0*,"
94		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
95		{ "OpenSSH_3.*",	SSH_OLD_FORWARD_ADDR },
96		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
97		{ "OpenSSH_4*",		0 },
98		{ "OpenSSH_5*",		SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
99		{ "OpenSSH*",		SSH_NEW_OPENSSH },
100		{ "*MindTerm*",		0 },
101		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
102					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
103					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
104					SSH_BUG_FIRSTKEX },
105		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
106					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
107					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
108					SSH_BUG_FIRSTKEX },
109		{ "2.0.13*,"
110		  "2.0.14*,"
111		  "2.0.15*,"
112		  "2.0.16*,"
113		  "2.0.17*,"
114		  "2.0.18*,"
115		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
116					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
117					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
118					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
119					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
120					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
121		{ "2.0.11*,"
122		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
123					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
124					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
125					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
126					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
127					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
128		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
129					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
130					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
131					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
132					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
133					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
134					SSH_BUG_FIRSTKEX },
135		{ "2.2.0*,"
136		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
137					SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
138		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
139					SSH_BUG_FIRSTKEX },
140		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
141		{ "2.*",		SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
142					SSH_BUG_RFWD_ADDR },
143		{ "3.0.*",		SSH_BUG_DEBUG },
144		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
145		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
146		{ "1.2.18*,"
147		  "1.2.19*,"
148		  "1.2.20*,"
149		  "1.2.21*,"
150		  "1.2.22*",		SSH_BUG_IGNOREMSG },
151		{ "1.3.2*",		/* F-Secure */
152					SSH_BUG_IGNOREMSG },
153		{ "*SSH Compatible Server*",			/* Netscreen */
154					SSH_BUG_PASSWORDPAD },
155		{ "*OSU_0*,"
156		  "OSU_1.0*,"
157		  "OSU_1.1*,"
158		  "OSU_1.2*,"
159		  "OSU_1.3*,"
160		  "OSU_1.4*,"
161		  "OSU_1.5alpha1*,"
162		  "OSU_1.5alpha2*,"
163		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
164		{ "*SSH_Version_Mapper*",
165					SSH_BUG_SCANNER },
166		{ "Probe-*",
167					SSH_BUG_PROBE },
168		{ NULL,			0 }
169	};
170
171	/* process table, return first match */
172	for (i = 0; check[i].pat; i++) {
173		if (match_pattern_list(version, check[i].pat,
174		    strlen(check[i].pat), 0) == 1) {
175			debug("match: %s pat %s", version, check[i].pat);
176			datafellows = check[i].bugs;
177			/*
178			 * Check to see if the remote side is OpenSSH and not
179			 * HPN.  It is utterly strange to check it from the
180			 * version string and expose the option that way.
181			 */
182			if (strstr(version,"OpenSSH") != NULL &&
183			    strstr(version,"hpn") == NULL) {
184				datafellows |= SSH_BUG_LARGEWINDOW;
185				debug("Remote is not HPN-aware");
186			}
187			return;
188		}
189	}
190	debug("no match: %s", version);
191}
192
193#define	SEP	","
194int
195proto_spec(const char *spec)
196{
197	char *s, *p, *q;
198	int ret = SSH_PROTO_UNKNOWN;
199
200	if (spec == NULL)
201		return ret;
202	q = s = xstrdup(spec);
203	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
204		switch (atoi(p)) {
205		case 1:
206			if (ret == SSH_PROTO_UNKNOWN)
207				ret |= SSH_PROTO_1_PREFERRED;
208			ret |= SSH_PROTO_1;
209			break;
210		case 2:
211			ret |= SSH_PROTO_2;
212			break;
213		default:
214			logit("ignoring bad proto spec: '%s'.", p);
215			break;
216		}
217	}
218	free(s);
219	return ret;
220}
221
222char *
223compat_cipher_proposal(char *cipher_prop)
224{
225	Buffer b;
226	char *orig_prop, *fix_ciphers;
227	char *cp, *tmp;
228
229	if (!(datafellows & SSH_BUG_BIGENDIANAES))
230		return(cipher_prop);
231
232	buffer_init(&b);
233	tmp = orig_prop = xstrdup(cipher_prop);
234	while ((cp = strsep(&tmp, ",")) != NULL) {
235		if (strncmp(cp, "aes", 3) != 0) {
236			if (buffer_len(&b) > 0)
237				buffer_append(&b, ",", 1);
238			buffer_append(&b, cp, strlen(cp));
239		}
240	}
241	buffer_append(&b, "\0", 1);
242	fix_ciphers = xstrdup(buffer_ptr(&b));
243	buffer_free(&b);
244	free(orig_prop);
245	debug2("Original cipher proposal: %s", cipher_prop);
246	debug2("Compat cipher proposal: %s", fix_ciphers);
247	if (!*fix_ciphers)
248		fatal("No available ciphers found.");
249
250	return(fix_ciphers);
251}
252