xref: /freebsd/crypto/openssh/compat.c (revision d3d381b2b194b4d24853e92eecef55f262688d1a)
1 /* $OpenBSD: compat.c,v 1.106 2018/02/16 04:43:11 dtucker 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 #include "kex.h"
41 
42 int datafellows = 0;
43 
44 /* datafellows bug compatibility */
45 u_int
46 compat_datafellows(const char *version)
47 {
48 	int i;
49 	static struct {
50 		char	*pat;
51 		int	bugs;
52 	} check[] = {
53 		{ "OpenSSH_2.*,"
54 		  "OpenSSH_3.0*,"
55 		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
56 		{ "OpenSSH_3.*",	SSH_OLD_FORWARD_ADDR },
57 		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
58 		{ "OpenSSH_2*,"
59 		  "OpenSSH_3*,"
60 		  "OpenSSH_4*",		0 },
61 		{ "OpenSSH_5*",		SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
62 		{ "OpenSSH_6.6.1*",	SSH_NEW_OPENSSH},
63 		{ "OpenSSH_6.5*,"
64 		  "OpenSSH_6.6*",	SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
65 		{ "OpenSSH*",		SSH_NEW_OPENSSH },
66 		{ "*MindTerm*",		0 },
67 		{ "3.0.*",		SSH_BUG_DEBUG },
68 		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
69 		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
70 		{ "1.2.18*,"
71 		  "1.2.19*,"
72 		  "1.2.20*,"
73 		  "1.2.21*,"
74 		  "1.2.22*",		SSH_BUG_IGNOREMSG },
75 		{ "1.3.2*",		/* F-Secure */
76 					SSH_BUG_IGNOREMSG },
77 		{ "Cisco-1.*",		SSH_BUG_DHGEX_LARGE|
78 					SSH_BUG_HOSTKEYS },
79 		{ "*SSH Compatible Server*",			/* Netscreen */
80 					SSH_BUG_PASSWORDPAD },
81 		{ "*OSU_0*,"
82 		  "OSU_1.0*,"
83 		  "OSU_1.1*,"
84 		  "OSU_1.2*,"
85 		  "OSU_1.3*,"
86 		  "OSU_1.4*,"
87 		  "OSU_1.5alpha1*,"
88 		  "OSU_1.5alpha2*,"
89 		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
90 		{ "*SSH_Version_Mapper*",
91 					SSH_BUG_SCANNER },
92 		{ "PuTTY_Local:*,"	/* dev versions < Sep 2014 */
93 		  "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
94 		  "PuTTY_Release_0.5*,"	/* 0.58-0.59 */
95 		  "PuTTY_Release_0.60*,"
96 		  "PuTTY_Release_0.61*,"
97 		  "PuTTY_Release_0.62*,"
98 		  "PuTTY_Release_0.63*,"
99 		  "PuTTY_Release_0.64*",
100 					SSH_OLD_DHGEX },
101 		{ "FuTTY*",		SSH_OLD_DHGEX }, /* Putty Fork */
102 		{ "Probe-*",
103 					SSH_BUG_PROBE },
104 		{ "TeraTerm SSH*,"
105 		  "TTSSH/1.5.*,"
106 		  "TTSSH/2.1*,"
107 		  "TTSSH/2.2*,"
108 		  "TTSSH/2.3*,"
109 		  "TTSSH/2.4*,"
110 		  "TTSSH/2.5*,"
111 		  "TTSSH/2.6*,"
112 		  "TTSSH/2.70*,"
113 		  "TTSSH/2.71*,"
114 		  "TTSSH/2.72*",	SSH_BUG_HOSTKEYS },
115 		{ "WinSCP_release_4*,"
116 		  "WinSCP_release_5.0*,"
117 		  "WinSCP_release_5.1,"
118 		  "WinSCP_release_5.1.*,"
119 		  "WinSCP_release_5.5,"
120 		  "WinSCP_release_5.5.*,"
121 		  "WinSCP_release_5.6,"
122 		  "WinSCP_release_5.6.*,"
123 		  "WinSCP_release_5.7,"
124 		  "WinSCP_release_5.7.1,"
125 		  "WinSCP_release_5.7.2,"
126 		  "WinSCP_release_5.7.3,"
127 		  "WinSCP_release_5.7.4",
128 					SSH_OLD_DHGEX },
129 		{ "ConfD-*",
130 					SSH_BUG_UTF8TTYMODE },
131 		{ NULL,			0 }
132 	};
133 
134 	/* process table, return first match */
135 	for (i = 0; check[i].pat; i++) {
136 		if (match_pattern_list(version, check[i].pat, 0) == 1) {
137 			debug("match: %s pat %s compat 0x%08x",
138 			    version, check[i].pat, check[i].bugs);
139 			datafellows = check[i].bugs;	/* XXX for now */
140 			return check[i].bugs;
141 		}
142 	}
143 	debug("no match: %s", version);
144 	return 0;
145 }
146 
147 #define	SEP	","
148 int
149 proto_spec(const char *spec)
150 {
151 	char *s, *p, *q;
152 	int ret = SSH_PROTO_UNKNOWN;
153 
154 	if (spec == NULL)
155 		return ret;
156 	q = s = strdup(spec);
157 	if (s == NULL)
158 		return ret;
159 	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
160 		switch (atoi(p)) {
161 		case 2:
162 			ret |= SSH_PROTO_2;
163 			break;
164 		default:
165 			logit("ignoring bad proto spec: '%s'.", p);
166 			break;
167 		}
168 	}
169 	free(s);
170 	return ret;
171 }
172 
173 char *
174 compat_cipher_proposal(char *cipher_prop)
175 {
176 	if (!(datafellows & SSH_BUG_BIGENDIANAES))
177 		return cipher_prop;
178 	debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
179 	if ((cipher_prop = match_filter_list(cipher_prop, "aes*")) == NULL)
180 		fatal("match_filter_list failed");
181 	debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
182 	if (*cipher_prop == '\0')
183 		fatal("No supported ciphers found");
184 	return cipher_prop;
185 }
186 
187 char *
188 compat_pkalg_proposal(char *pkalg_prop)
189 {
190 	if (!(datafellows & SSH_BUG_RSASIGMD5))
191 		return pkalg_prop;
192 	debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
193 	if ((pkalg_prop = match_filter_list(pkalg_prop, "ssh-rsa")) == NULL)
194 		fatal("match_filter_list failed");
195 	debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
196 	if (*pkalg_prop == '\0')
197 		fatal("No supported PK algorithms found");
198 	return pkalg_prop;
199 }
200 
201 char *
202 compat_kex_proposal(char *p)
203 {
204 	if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
205 		return p;
206 	debug2("%s: original KEX proposal: %s", __func__, p);
207 	if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
208 		if ((p = match_filter_list(p,
209 		    "curve25519-sha256@libssh.org")) == NULL)
210 			fatal("match_filter_list failed");
211 	if ((datafellows & SSH_OLD_DHGEX) != 0) {
212 		if ((p = match_filter_list(p,
213 		    "diffie-hellman-group-exchange-sha256,"
214 		    "diffie-hellman-group-exchange-sha1")) == NULL)
215 			fatal("match_filter_list failed");
216 	}
217 	debug2("%s: compat KEX proposal: %s", __func__, p);
218 	if (*p == '\0')
219 		fatal("No supported key exchange algorithms found");
220 	return p;
221 }
222 
223