xref: /openbsd-src/usr.bin/ssh/compat.c (revision 3a3fbb3f2e2521ab7c4a56b7ff7462ebd9095ec5)
1 /*
2  * Copyright (c) 1999, 2000, 2001 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"
26 RCSID("$OpenBSD: compat.c,v 1.56 2001/12/19 07:18:56 deraadt Exp $");
27 
28 #include "packet.h"
29 #include "xmalloc.h"
30 #include "compat.h"
31 #include "log.h"
32 #include "match.h"
33 
34 int compat13 = 0;
35 int compat20 = 0;
36 int datafellows = 0;
37 
38 void
39 enable_compat20(void)
40 {
41 	verbose("Enabling compatibility mode for protocol 2.0");
42 	compat20 = 1;
43 }
44 void
45 enable_compat13(void)
46 {
47 	verbose("Enabling compatibility mode for protocol 1.3");
48 	compat13 = 1;
49 }
50 /* datafellows bug compatibility */
51 void
52 compat_datafellows(const char *version)
53 {
54 	int i;
55 	static struct {
56 		char	*pat;
57 		int	bugs;
58 	} check[] = {
59 		{ "OpenSSH-2.0*,"
60 		  "OpenSSH-2.1*,"
61 		  "OpenSSH_2.1*,"
62 		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
63 					SSH_OLD_DHGEX|SSH_BUG_NOREKEY },
64 		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
65 					SSH_OLD_DHGEX|SSH_BUG_NOREKEY},
66 		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
67 					SSH_BUG_NOREKEY},
68 		{ "OpenSSH_2.5.0p1*,"
69 		  "OpenSSH_2.5.1p1*",
70 					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
71 					SSH_BUG_NOREKEY },
72 		{ "OpenSSH_2.5.0*,"
73 		  "OpenSSH_2.5.1*,"
74 		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY },
75 		{ "OpenSSH_2.5.3*",
76 					SSH_BUG_NOREKEY },
77 		{ "OpenSSH*",		0 },
78 		{ "*MindTerm*",		0 },
79 		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
80 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
81 					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE },
82 		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
83 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
84 					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE },
85 		{ "2.0.13*,"
86 		  "2.0.14*,"
87 		  "2.0.15*,"
88 		  "2.0.16*,"
89 		  "2.0.17*,"
90 		  "2.0.18*,"
91 		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
92 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
93 					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
94 					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
95 					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
96 					SSH_BUG_DUMMYCHAN },
97 		{ "2.0.11*,"
98 		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
99 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
100 					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
101 					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
102 					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
103 					SSH_BUG_DUMMYCHAN },
104 		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
105 					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
106 					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
107 					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
108 					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
109 					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN },
110 		{ "2.2.0*,"
111 		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
112 					SSH_BUG_RSASIGMD5 },
113 		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5 },
114 		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
115 		{ "2.*",		SSH_BUG_DEBUG },
116 		{ "3.0.*",		SSH_BUG_DEBUG },
117 		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
118 		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
119 		{ "1.2.18*,"
120 		  "1.2.19*,"
121 		  "1.2.20*,"
122 		  "1.2.21*,"
123 		  "1.2.22*",		SSH_BUG_IGNOREMSG },
124 		{ "1.3.2*",		SSH_BUG_IGNOREMSG },	/* f-secure */
125 		{ "*SSH Compatible Server*",			/* Netscreen */
126 					SSH_BUG_PASSWORDPAD },
127 		{ "*OSU_0*,"
128 		  "OSU_1.0*,"
129 		  "OSU_1.1*,"
130 		  "OSU_1.2*,"
131 		  "OSU_1.3*,"
132 		  "OSU_1.4*,"
133 		  "OSU_1.5alpha1*,"
134 		  "OSU_1.5alpha2*,"
135 		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
136 		{ "*SSH_Version_Mapper*",
137 					SSH_BUG_SCANNER },
138 		{ NULL,			0 }
139 	};
140 
141 	/* process table, return first match */
142 	for (i = 0; check[i].pat; i++) {
143 		if (match_pattern_list(version, check[i].pat,
144 		    strlen(check[i].pat), 0) == 1) {
145 			debug("match: %s pat %s", version, check[i].pat);
146 			datafellows = check[i].bugs;
147 			return;
148 		}
149 	}
150 	debug("no match: %s", version);
151 }
152 
153 #define	SEP	","
154 int
155 proto_spec(const char *spec)
156 {
157 	char *s, *p, *q;
158 	int ret = SSH_PROTO_UNKNOWN;
159 
160 	if (spec == NULL)
161 		return ret;
162 	q = s = xstrdup(spec);
163 	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
164 		switch (atoi(p)) {
165 		case 1:
166 			if (ret == SSH_PROTO_UNKNOWN)
167 				ret |= SSH_PROTO_1_PREFERRED;
168 			ret |= SSH_PROTO_1;
169 			break;
170 		case 2:
171 			ret |= SSH_PROTO_2;
172 			break;
173 		default:
174 			log("ignoring bad proto spec: '%s'.", p);
175 			break;
176 		}
177 	}
178 	xfree(s);
179 	return ret;
180 }
181 
182 char *
183 compat_cipher_proposal(char *cipher_prop)
184 {
185 	char *orig_prop, *fix_ciphers;
186 	char *cp, *tmp;
187 	size_t len;
188 
189 	if (!(datafellows & SSH_BUG_BIGENDIANAES))
190 		return(cipher_prop);
191 
192 	len = strlen(cipher_prop) + 1;
193 	fix_ciphers = xmalloc(len);
194 	*fix_ciphers = '\0';
195 	tmp = orig_prop = xstrdup(cipher_prop);
196 	while ((cp = strsep(&tmp, ",")) != NULL) {
197 		if (strncmp(cp, "aes", 3) && strncmp(cp, "rijndael", 8)) {
198 			if (*fix_ciphers)
199 				strlcat(fix_ciphers, ",", len);
200 			strlcat(fix_ciphers, cp, len);
201 		}
202 	}
203 	xfree(orig_prop);
204 	debug2("Original cipher proposal: %s", cipher_prop);
205 	debug2("Compat cipher proposal: %s", fix_ciphers);
206 	if (!*fix_ciphers)
207 		fatal("No available ciphers found.");
208 
209 	return(fix_ciphers);
210 }
211