xref: /freebsd/crypto/openssh/compat.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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 __RCSID("$FreeBSD$");
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 
42 int compat13 = 0;
43 int compat20 = 0;
44 int datafellows = 0;
45 
46 void
47 enable_compat20(void)
48 {
49 	debug("Enabling compatibility mode for protocol 2.0");
50 	compat20 = 1;
51 }
52 void
53 enable_compat13(void)
54 {
55 	debug("Enabling compatibility mode for protocol 1.3");
56 	compat13 = 1;
57 }
58 /* datafellows bug compatibility */
59 void
60 compat_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*",		0 },
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 		{ "3.0.*",		SSH_BUG_DEBUG },
139 		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
140 		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
141 		{ "1.2.18*,"
142 		  "1.2.19*,"
143 		  "1.2.20*,"
144 		  "1.2.21*,"
145 		  "1.2.22*",		SSH_BUG_IGNOREMSG },
146 		{ "1.3.2*",		/* F-Secure */
147 					SSH_BUG_IGNOREMSG },
148 		{ "*SSH Compatible Server*",			/* Netscreen */
149 					SSH_BUG_PASSWORDPAD },
150 		{ "*OSU_0*,"
151 		  "OSU_1.0*,"
152 		  "OSU_1.1*,"
153 		  "OSU_1.2*,"
154 		  "OSU_1.3*,"
155 		  "OSU_1.4*,"
156 		  "OSU_1.5alpha1*,"
157 		  "OSU_1.5alpha2*,"
158 		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
159 		{ "*SSH_Version_Mapper*",
160 					SSH_BUG_SCANNER },
161 		{ "Probe-*",
162 					SSH_BUG_PROBE },
163 		{ NULL,			0 }
164 	};
165 
166 	/* process table, return first match */
167 	for (i = 0; check[i].pat; i++) {
168 		if (match_pattern_list(version, check[i].pat,
169 		    strlen(check[i].pat), 0) == 1) {
170 			debug("match: %s pat %s", version, check[i].pat);
171 			datafellows = check[i].bugs;
172 			return;
173 		}
174 	}
175 	debug("no match: %s", version);
176 }
177 
178 #define	SEP	","
179 int
180 proto_spec(const char *spec)
181 {
182 	char *s, *p, *q;
183 	int ret = SSH_PROTO_UNKNOWN;
184 
185 	if (spec == NULL)
186 		return ret;
187 	q = s = xstrdup(spec);
188 	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
189 		switch (atoi(p)) {
190 		case 1:
191 			if (ret == SSH_PROTO_UNKNOWN)
192 				ret |= SSH_PROTO_1_PREFERRED;
193 			ret |= SSH_PROTO_1;
194 			break;
195 		case 2:
196 			ret |= SSH_PROTO_2;
197 			break;
198 		default:
199 			logit("ignoring bad proto spec: '%s'.", p);
200 			break;
201 		}
202 	}
203 	xfree(s);
204 	return ret;
205 }
206 
207 char *
208 compat_cipher_proposal(char *cipher_prop)
209 {
210 	Buffer b;
211 	char *orig_prop, *fix_ciphers;
212 	char *cp, *tmp;
213 
214 	if (!(datafellows & SSH_BUG_BIGENDIANAES))
215 		return(cipher_prop);
216 
217 	buffer_init(&b);
218 	tmp = orig_prop = xstrdup(cipher_prop);
219 	while ((cp = strsep(&tmp, ",")) != NULL) {
220 		if (strncmp(cp, "aes", 3) != 0) {
221 			if (buffer_len(&b) > 0)
222 				buffer_append(&b, ",", 1);
223 			buffer_append(&b, cp, strlen(cp));
224 		}
225 	}
226 	buffer_append(&b, "\0", 1);
227 	fix_ciphers = xstrdup(buffer_ptr(&b));
228 	buffer_free(&b);
229 	xfree(orig_prop);
230 	debug2("Original cipher proposal: %s", cipher_prop);
231 	debug2("Compat cipher proposal: %s", fix_ciphers);
232 	if (!*fix_ciphers)
233 		fatal("No available ciphers found.");
234 
235 	return(fix_ciphers);
236 }
237