compat.c revision 224640 
1/* $OpenBSD: compat.c,v 1.78 2008/09/11 14:22:37 markus Exp $ */
2/* $FreeBSD: head/crypto/openssh/compat.c 224640 2011-08-03 20:00:36Z brooks $ */
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	debug("Enabling compatibility mode for protocol 2.0");
50	compat20 = 1;
51}
52void
53enable_compat13(void)
54{
55	debug("Enabling compatibility mode for protocol 1.3");
56	compat13 = 1;
57}
58/* datafellows bug compatibility */
59void
60compat_datafellows(const char *version)
61{
62	int i;
63	static struct {
64		char	*pat;
65		int	bugs;
66	} check[] = {
67		{ "OpenSSH-2.0*,"
68		  "OpenSSH-2.1*,"
69		  "OpenSSH_2.1*,"
70		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
71					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
72					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
73		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
74					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
75					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
76		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
77					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
78					SSH_OLD_FORWARD_ADDR},
79		{ "OpenSSH_2.5.0p1*,"
80		  "OpenSSH_2.5.1p1*",
81					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
82					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
83					SSH_OLD_FORWARD_ADDR},
84		{ "OpenSSH_2.5.0*,"
85		  "OpenSSH_2.5.1*,"
86		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
87					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
88		{ "OpenSSH_2.5.3*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
89					SSH_OLD_FORWARD_ADDR},
90		{ "OpenSSH_2.*,"
91		  "OpenSSH_3.0*,"
92		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
93		{ "OpenSSH_3.*",	SSH_OLD_FORWARD_ADDR },
94		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
95		{ "OpenSSH_4*",		0 },
96		{ "OpenSSH*",		SSH_NEW_OPENSSH },
97		{ "*MindTerm*",		0 },
98		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
99					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
100					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
101					SSH_BUG_FIRSTKEX },
102		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
103					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
104					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
105					SSH_BUG_FIRSTKEX },
106		{ "2.0.13*,"
107		  "2.0.14*,"
108		  "2.0.15*,"
109		  "2.0.16*,"
110		  "2.0.17*,"
111		  "2.0.18*,"
112		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
113					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
114					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
115					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
116					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
117					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
118		{ "2.0.11*,"
119		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
120					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
121					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
122					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
123					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
124					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
125		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
126					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
127					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
128					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
129					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
130					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
131					SSH_BUG_FIRSTKEX },
132		{ "2.2.0*,"
133		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
134					SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
135		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
136					SSH_BUG_FIRSTKEX },
137		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
138		{ "2.*",		SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
139					SSH_BUG_RFWD_ADDR },
140		{ "3.0.*",		SSH_BUG_DEBUG },
141		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
142		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
143		{ "1.2.18*,"
144		  "1.2.19*,"
145		  "1.2.20*,"
146		  "1.2.21*,"
147		  "1.2.22*",		SSH_BUG_IGNOREMSG },
148		{ "1.3.2*",		/* F-Secure */
149					SSH_BUG_IGNOREMSG },
150		{ "*SSH Compatible Server*",			/* Netscreen */
151					SSH_BUG_PASSWORDPAD },
152		{ "*OSU_0*,"
153		  "OSU_1.0*,"
154		  "OSU_1.1*,"
155		  "OSU_1.2*,"
156		  "OSU_1.3*,"
157		  "OSU_1.4*,"
158		  "OSU_1.5alpha1*,"
159		  "OSU_1.5alpha2*,"
160		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
161		{ "*SSH_Version_Mapper*",
162					SSH_BUG_SCANNER },
163		{ "Probe-*",
164					SSH_BUG_PROBE },
165		{ NULL,			0 }
166	};
167
168	/* process table, return first match */
169	for (i = 0; check[i].pat; i++) {
170		if (match_pattern_list(version, check[i].pat,
171		    strlen(check[i].pat), 0) == 1) {
172			debug("match: %s pat %s", version, check[i].pat);
173			datafellows = check[i].bugs;
174			/*
175			 * Check to see if the remote side is OpenSSH and not
176			 * HPN.  It is utterly strange to check it from the
177			 * version string and expose the option that way.
178			 */
179			if (strstr(version,"OpenSSH") != NULL &&
180			    strstr(version,"hpn") == NULL) {
181				datafellows |= SSH_BUG_LARGEWINDOW;
182				debug("Remote is not HPN-aware");
183			}
184			return;
185		}
186	}
187	debug("no match: %s", version);
188}
189
190#define	SEP	","
191int
192proto_spec(const char *spec)
193{
194	char *s, *p, *q;
195	int ret = SSH_PROTO_UNKNOWN;
196
197	if (spec == NULL)
198		return ret;
199	q = s = xstrdup(spec);
200	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
201		switch (atoi(p)) {
202		case 1:
203			if (ret == SSH_PROTO_UNKNOWN)
204				ret |= SSH_PROTO_1_PREFERRED;
205			ret |= SSH_PROTO_1;
206			break;
207		case 2:
208			ret |= SSH_PROTO_2;
209			break;
210		default:
211			logit("ignoring bad proto spec: '%s'.", p);
212			break;
213		}
214	}
215	xfree(s);
216	return ret;
217}
218
219char *
220compat_cipher_proposal(char *cipher_prop)
221{
222	Buffer b;
223	char *orig_prop, *fix_ciphers;
224	char *cp, *tmp;
225
226	if (!(datafellows & SSH_BUG_BIGENDIANAES))
227		return(cipher_prop);
228
229	buffer_init(&b);
230	tmp = orig_prop = xstrdup(cipher_prop);
231	while ((cp = strsep(&tmp, ",")) != NULL) {
232		if (strncmp(cp, "aes", 3) != 0) {
233			if (buffer_len(&b) > 0)
234				buffer_append(&b, ",", 1);
235			buffer_append(&b, cp, strlen(cp));
236		}
237	}
238	buffer_append(&b, "\0", 1);
239	fix_ciphers = xstrdup(buffer_ptr(&b));
240	buffer_free(&b);
241	xfree(orig_prop);
242	debug2("Original cipher proposal: %s", cipher_prop);
243	debug2("Compat cipher proposal: %s", fix_ciphers);
244	if (!*fix_ciphers)
245		fatal("No available ciphers found.");
246
247	return(fix_ciphers);
248}
249