compat.c revision 192595 
1/* $OpenBSD: compat.c,v 1.78 2008/09/11 14:22:37 markus Exp $ */
2/*
3 * Copyright (c) 1999, 2000, 2001, 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 "includes.h"
27
28#include <sys/types.h>
29
30#include <stdlib.h>
31#include <string.h>
32#include <stdarg.h>
33
34#include "xmalloc.h"
35#include "buffer.h"
36#include "packet.h"
37#include "compat.h"
38#include "log.h"
39#include "match.h"
40
41int compat13 = 0;
42int compat20 = 0;
43int datafellows = 0;
44
45void
46enable_compat20(void)
47{
48	debug("Enabling compatibility mode for protocol 2.0");
49	compat20 = 1;
50}
51void
52enable_compat13(void)
53{
54	debug("Enabling compatibility mode for protocol 1.3");
55	compat13 = 1;
56}
57/* datafellows bug compatibility */
58void
59compat_datafellows(const char *version)
60{
61	int i;
62	static struct {
63		char	*pat;
64		int	bugs;
65	} check[] = {
66		{ "OpenSSH-2.0*,"
67		  "OpenSSH-2.1*,"
68		  "OpenSSH_2.1*,"
69		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
70					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
71					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
72		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
73					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
74					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
75		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
76					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
77					SSH_OLD_FORWARD_ADDR},
78		{ "OpenSSH_2.5.0p1*,"
79		  "OpenSSH_2.5.1p1*",
80					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
81					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
82					SSH_OLD_FORWARD_ADDR},
83		{ "OpenSSH_2.5.0*,"
84		  "OpenSSH_2.5.1*,"
85		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
86					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
87		{ "OpenSSH_2.5.3*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
88					SSH_OLD_FORWARD_ADDR},
89		{ "OpenSSH_2.*,"
90		  "OpenSSH_3.0*,"
91		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
92		{ "OpenSSH_3.*",	SSH_OLD_FORWARD_ADDR },
93		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
94		{ "OpenSSH_4*",		0 },
95		{ "OpenSSH*",		SSH_NEW_OPENSSH },
96		{ "*MindTerm*",		0 },
97		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
98					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
99					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
100					SSH_BUG_FIRSTKEX },
101		{ "2.1 *",		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		{ "2.0.13*,"
106		  "2.0.14*,"
107		  "2.0.15*,"
108		  "2.0.16*,"
109		  "2.0.17*,"
110		  "2.0.18*,"
111		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
112					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
113					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
114					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
115					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
116					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
117		{ "2.0.11*,"
118		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
119					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
120					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
121					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
122					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
123					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
124		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
125					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
126					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
127					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
128					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
129					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
130					SSH_BUG_FIRSTKEX },
131		{ "2.2.0*,"
132		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
133					SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
134		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
135					SSH_BUG_FIRSTKEX },
136		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
137		{ "2.*",		SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
138					SSH_BUG_RFWD_ADDR },
139		{ "3.0.*",		SSH_BUG_DEBUG },
140		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
141		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
142		{ "1.2.18*,"
143		  "1.2.19*,"
144		  "1.2.20*,"
145		  "1.2.21*,"
146		  "1.2.22*",		SSH_BUG_IGNOREMSG },
147		{ "1.3.2*",		/* F-Secure */
148					SSH_BUG_IGNOREMSG },
149		{ "*SSH Compatible Server*",			/* Netscreen */
150					SSH_BUG_PASSWORDPAD },
151		{ "*OSU_0*,"
152		  "OSU_1.0*,"
153		  "OSU_1.1*,"
154		  "OSU_1.2*,"
155		  "OSU_1.3*,"
156		  "OSU_1.4*,"
157		  "OSU_1.5alpha1*,"
158		  "OSU_1.5alpha2*,"
159		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
160		{ "*SSH_Version_Mapper*",
161					SSH_BUG_SCANNER },
162		{ "Probe-*",
163					SSH_BUG_PROBE },
164		{ NULL,			0 }
165	};
166
167	/* process table, return first match */
168	for (i = 0; check[i].pat; i++) {
169		if (match_pattern_list(version, check[i].pat,
170		    strlen(check[i].pat), 0) == 1) {
171			debug("match: %s pat %s", version, check[i].pat);
172			datafellows = check[i].bugs;
173			return;
174		}
175	}
176	debug("no match: %s", version);
177}
178
179#define	SEP	","
180int
181proto_spec(const char *spec)
182{
183	char *s, *p, *q;
184	int ret = SSH_PROTO_UNKNOWN;
185
186	if (spec == NULL)
187		return ret;
188	q = s = xstrdup(spec);
189	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
190		switch (atoi(p)) {
191		case 1:
192			if (ret == SSH_PROTO_UNKNOWN)
193				ret |= SSH_PROTO_1_PREFERRED;
194			ret |= SSH_PROTO_1;
195			break;
196		case 2:
197			ret |= SSH_PROTO_2;
198			break;
199		default:
200			logit("ignoring bad proto spec: '%s'.", p);
201			break;
202		}
203	}
204	xfree(s);
205	return ret;
206}
207
208char *
209compat_cipher_proposal(char *cipher_prop)
210{
211	Buffer b;
212	char *orig_prop, *fix_ciphers;
213	char *cp, *tmp;
214
215	if (!(datafellows & SSH_BUG_BIGENDIANAES))
216		return(cipher_prop);
217
218	buffer_init(&b);
219	tmp = orig_prop = xstrdup(cipher_prop);
220	while ((cp = strsep(&tmp, ",")) != NULL) {
221		if (strncmp(cp, "aes", 3) != 0) {
222			if (buffer_len(&b) > 0)
223				buffer_append(&b, ",", 1);
224			buffer_append(&b, cp, strlen(cp));
225		}
226	}
227	buffer_append(&b, "\0", 1);
228	fix_ciphers = xstrdup(buffer_ptr(&b));
229	buffer_free(&b);
230	xfree(orig_prop);
231	debug2("Original cipher proposal: %s", cipher_prop);
232	debug2("Compat cipher proposal: %s", fix_ciphers);
233	if (!*fix_ciphers)
234		fatal("No available ciphers found.");
235
236	return(fix_ciphers);
237}
238