compat.c revision 98941 
1/*
2 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
14 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
15 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
16 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
17 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
18 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
19 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
20 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
22 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#include "includes.h"
26RCSID("$OpenBSD: compat.c,v 1.63 2002/04/10 08:21:47 markus Exp $");
27
28#include "buffer.h"
29#include "packet.h"
30#include "xmalloc.h"
31#include "compat.h"
32#include "log.h"
33#include "match.h"
34
35int compat13 = 0;
36int compat20 = 0;
37int datafellows = 0;
38
39void
40enable_compat20(void)
41{
42	verbose("Enabling compatibility mode for protocol 2.0");
43	compat20 = 1;
44}
45void
46enable_compat13(void)
47{
48	verbose("Enabling compatibility mode for protocol 1.3");
49	compat13 = 1;
50}
51/* datafellows bug compatibility */
52void
53compat_datafellows(const char *version)
54{
55	int i;
56	static struct {
57		char	*pat;
58		int	bugs;
59	} check[] = {
60		{ "OpenSSH-2.0*,"
61		  "OpenSSH-2.1*,"
62		  "OpenSSH_2.1*,"
63		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
64					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
65					SSH_BUG_EXTEOF},
66		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
67					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
68					SSH_BUG_EXTEOF},
69		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
70					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
71		{ "OpenSSH_2.5.0p1*,"
72		  "OpenSSH_2.5.1p1*",
73					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
74					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
75		{ "OpenSSH_2.5.0*,"
76		  "OpenSSH_2.5.1*,"
77		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
78					SSH_BUG_EXTEOF},
79		{ "OpenSSH_2.5.3*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
80		{ "OpenSSH_2.*,"
81		  "OpenSSH_3.0*,"
82		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF},
83		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
84		{ "OpenSSH*",		0 },
85		{ "*MindTerm*",		0 },
86		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
87					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
88					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE },
89		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
90					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
91					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE },
92		{ "2.0.13*,"
93		  "2.0.14*,"
94		  "2.0.15*,"
95		  "2.0.16*,"
96		  "2.0.17*,"
97		  "2.0.18*,"
98		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
99					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
100					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
101					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
102					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
103					SSH_BUG_DUMMYCHAN },
104		{ "2.0.11*,"
105		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
106					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
107					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
108					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
109					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
110					SSH_BUG_DUMMYCHAN },
111		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
112					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
113					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
114					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
115					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
116					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN },
117		{ "2.2.0*,"
118		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
119					SSH_BUG_RSASIGMD5 },
120		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5 },
121		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
122		{ "2.*",		SSH_BUG_DEBUG },
123		{ "3.0.*",		SSH_BUG_DEBUG },
124		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
125		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
126		{ "1.2.18*,"
127		  "1.2.19*,"
128		  "1.2.20*,"
129		  "1.2.21*,"
130		  "1.2.22*",		SSH_BUG_IGNOREMSG|SSH_BUG_K5USER },
131		{ "1.3.2*",		/* F-Secure */
132					SSH_BUG_IGNOREMSG|SSH_BUG_K5USER },
133		{ "1.2.1*,"
134		  "1.2.2*,"
135		  "1.2.3*",		SSH_BUG_K5USER },
136		{ "*SSH Compatible Server*",			/* Netscreen */
137					SSH_BUG_PASSWORDPAD },
138		{ "*OSU_0*,"
139		  "OSU_1.0*,"
140		  "OSU_1.1*,"
141		  "OSU_1.2*,"
142		  "OSU_1.3*,"
143		  "OSU_1.4*,"
144		  "OSU_1.5alpha1*,"
145		  "OSU_1.5alpha2*,"
146		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
147		{ "*SSH_Version_Mapper*",
148					SSH_BUG_SCANNER },
149		{ NULL,			0 }
150	};
151
152	/* process table, return first match */
153	for (i = 0; check[i].pat; i++) {
154		if (match_pattern_list(version, check[i].pat,
155		    strlen(check[i].pat), 0) == 1) {
156			debug("match: %s pat %s", version, check[i].pat);
157			datafellows = check[i].bugs;
158			return;
159		}
160	}
161	debug("no match: %s", version);
162}
163
164#define	SEP	","
165int
166proto_spec(const char *spec)
167{
168	char *s, *p, *q;
169	int ret = SSH_PROTO_UNKNOWN;
170
171	if (spec == NULL)
172		return ret;
173	q = s = xstrdup(spec);
174	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
175		switch (atoi(p)) {
176		case 1:
177			if (ret == SSH_PROTO_UNKNOWN)
178				ret |= SSH_PROTO_1_PREFERRED;
179			ret |= SSH_PROTO_1;
180			break;
181		case 2:
182			ret |= SSH_PROTO_2;
183			break;
184		default:
185			log("ignoring bad proto spec: '%s'.", p);
186			break;
187		}
188	}
189	xfree(s);
190	return ret;
191}
192
193char *
194compat_cipher_proposal(char *cipher_prop)
195{
196	Buffer b;
197	char *orig_prop, *fix_ciphers;
198	char *cp, *tmp;
199
200	if (!(datafellows & SSH_BUG_BIGENDIANAES))
201		return(cipher_prop);
202
203	buffer_init(&b);
204	tmp = orig_prop = xstrdup(cipher_prop);
205	while ((cp = strsep(&tmp, ",")) != NULL) {
206		if (strncmp(cp, "aes", 3) != 0) {
207			if (buffer_len(&b) > 0)
208				buffer_append(&b, ",", 1);
209			buffer_append(&b, cp, strlen(cp));
210		}
211	}
212	buffer_append(&b, "\0", 1);
213	fix_ciphers = xstrdup(buffer_ptr(&b));
214	buffer_free(&b);
215	xfree(orig_prop);
216	debug2("Original cipher proposal: %s", cipher_prop);
217	debug2("Compat cipher proposal: %s", fix_ciphers);
218	if (!*fix_ciphers)
219		fatal("No available ciphers found.");
220
221	return(fix_ciphers);
222}
223