compat.c revision 181106 
1/* $OpenBSD: compat.c,v 1.76 2006/08/03 03:34:42 deraadt 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*",		0 },
95		{ "*MindTerm*",		0 },
96		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
97					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
98					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
99					SSH_BUG_FIRSTKEX },
100		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
101					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
102					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
103					SSH_BUG_FIRSTKEX },
104		{ "2.0.13*,"
105		  "2.0.14*,"
106		  "2.0.15*,"
107		  "2.0.16*,"
108		  "2.0.17*,"
109		  "2.0.18*,"
110		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
111					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
112					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
113					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
114					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
115					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
116		{ "2.0.11*,"
117		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
118					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
119					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
120					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
121					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
122					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
123		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
124					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
125					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
126					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
127					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
128					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
129					SSH_BUG_FIRSTKEX },
130		{ "2.2.0*,"
131		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
132					SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
133		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
134					SSH_BUG_FIRSTKEX },
135		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
136		{ "2.*",		SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX },
137		{ "3.0.*",		SSH_BUG_DEBUG },
138		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
139		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
140		{ "1.2.18*,"
141		  "1.2.19*,"
142		  "1.2.20*,"
143		  "1.2.21*,"
144		  "1.2.22*",		SSH_BUG_IGNOREMSG },
145		{ "1.3.2*",		/* F-Secure */
146					SSH_BUG_IGNOREMSG },
147		{ "*SSH Compatible Server*",			/* Netscreen */
148					SSH_BUG_PASSWORDPAD },
149		{ "*OSU_0*,"
150		  "OSU_1.0*,"
151		  "OSU_1.1*,"
152		  "OSU_1.2*,"
153		  "OSU_1.3*,"
154		  "OSU_1.4*,"
155		  "OSU_1.5alpha1*,"
156		  "OSU_1.5alpha2*,"
157		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
158		{ "*SSH_Version_Mapper*",
159					SSH_BUG_SCANNER },
160		{ "Probe-*",
161					SSH_BUG_PROBE },
162		{ NULL,			0 }
163	};
164
165	/* process table, return first match */
166	for (i = 0; check[i].pat; i++) {
167		if (match_pattern_list(version, check[i].pat,
168		    strlen(check[i].pat), 0) == 1) {
169			debug("match: %s pat %s", version, check[i].pat);
170			datafellows = check[i].bugs;
171			return;
172		}
173	}
174	debug("no match: %s", version);
175}
176
177#define	SEP	","
178int
179proto_spec(const char *spec)
180{
181	char *s, *p, *q;
182	int ret = SSH_PROTO_UNKNOWN;
183
184	if (spec == NULL)
185		return ret;
186	q = s = xstrdup(spec);
187	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
188		switch (atoi(p)) {
189		case 1:
190			if (ret == SSH_PROTO_UNKNOWN)
191				ret |= SSH_PROTO_1_PREFERRED;
192			ret |= SSH_PROTO_1;
193			break;
194		case 2:
195			ret |= SSH_PROTO_2;
196			break;
197		default:
198			logit("ignoring bad proto spec: '%s'.", p);
199			break;
200		}
201	}
202	xfree(s);
203	return ret;
204}
205
206char *
207compat_cipher_proposal(char *cipher_prop)
208{
209	Buffer b;
210	char *orig_prop, *fix_ciphers;
211	char *cp, *tmp;
212
213	if (!(datafellows & SSH_BUG_BIGENDIANAES))
214		return(cipher_prop);
215
216	buffer_init(&b);
217	tmp = orig_prop = xstrdup(cipher_prop);
218	while ((cp = strsep(&tmp, ",")) != NULL) {
219		if (strncmp(cp, "aes", 3) != 0) {
220			if (buffer_len(&b) > 0)
221				buffer_append(&b, ",", 1);
222			buffer_append(&b, cp, strlen(cp));
223		}
224	}
225	buffer_append(&b, "\0", 1);
226	fix_ciphers = xstrdup(buffer_ptr(&b));
227	buffer_free(&b);
228	xfree(orig_prop);
229	debug2("Original cipher proposal: %s", cipher_prop);
230	debug2("Compat cipher proposal: %s", fix_ciphers);
231	if (!*fix_ciphers)
232		fatal("No available ciphers found.");
233
234	return(fix_ciphers);
235}
236