1 /* $OpenBSD: compat.c,v 1.113 2018/08/13 02:41:05 djm 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 "packet.h"
36 #include "compat.h"
37 #include "log.h"
38 #include "match.h"
39 #include "kex.h"
40
41 int datafellows = 0;
42
43 /* datafellows bug compatibility */
44 u_int
compat_datafellows(const char * version)45 compat_datafellows(const char *version)
46 {
47 int i;
48 static struct {
49 char *pat;
50 int bugs;
51 } check[] = {
52 { "OpenSSH_2.*,"
53 "OpenSSH_3.0*,"
54 "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR|
55 SSH_BUG_SIGTYPE},
56 { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE },
57 { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
58 SSH_BUG_SIGTYPE},
59 { "OpenSSH_2*,"
60 "OpenSSH_3*,"
61 "OpenSSH_4*", SSH_BUG_SIGTYPE },
62 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT|
63 SSH_BUG_SIGTYPE},
64 { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
65 { "OpenSSH_6.5*,"
66 "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD|
67 SSH_BUG_SIGTYPE},
68 { "OpenSSH_7.0*,"
69 "OpenSSH_7.1*,"
70 "OpenSSH_7.2*,"
71 "OpenSSH_7.3*,"
72 "OpenSSH_7.4*,"
73 "OpenSSH_7.5*,"
74 "OpenSSH_7.6*,"
75 "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE},
76 { "OpenSSH*", SSH_NEW_OPENSSH },
77 { "*MindTerm*", 0 },
78 { "3.0.*", SSH_BUG_DEBUG },
79 { "3.0 SecureCRT*", SSH_OLD_SESSIONID },
80 { "1.7 SecureFX*", SSH_OLD_SESSIONID },
81 { "1.2.18*,"
82 "1.2.19*,"
83 "1.2.20*,"
84 "1.2.21*,"
85 "1.2.22*", SSH_BUG_IGNOREMSG },
86 { "1.3.2*", /* F-Secure */
87 SSH_BUG_IGNOREMSG },
88 { "Cisco-1.*", SSH_BUG_DHGEX_LARGE|
89 SSH_BUG_HOSTKEYS },
90 { "*SSH Compatible Server*", /* Netscreen */
91 SSH_BUG_PASSWORDPAD },
92 { "*OSU_0*,"
93 "OSU_1.0*,"
94 "OSU_1.1*,"
95 "OSU_1.2*,"
96 "OSU_1.3*,"
97 "OSU_1.4*,"
98 "OSU_1.5alpha1*,"
99 "OSU_1.5alpha2*,"
100 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
101 { "*SSH_Version_Mapper*",
102 SSH_BUG_SCANNER },
103 { "PuTTY_Local:*," /* dev versions < Sep 2014 */
104 "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
105 "PuTTY_Release_0.5*," /* 0.58-0.59 */
106 "PuTTY_Release_0.60*,"
107 "PuTTY_Release_0.61*,"
108 "PuTTY_Release_0.62*,"
109 "PuTTY_Release_0.63*,"
110 "PuTTY_Release_0.64*",
111 SSH_OLD_DHGEX },
112 { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */
113 { "Probe-*",
114 SSH_BUG_PROBE },
115 { "TeraTerm SSH*,"
116 "TTSSH/1.5.*,"
117 "TTSSH/2.1*,"
118 "TTSSH/2.2*,"
119 "TTSSH/2.3*,"
120 "TTSSH/2.4*,"
121 "TTSSH/2.5*,"
122 "TTSSH/2.6*,"
123 "TTSSH/2.70*,"
124 "TTSSH/2.71*,"
125 "TTSSH/2.72*", SSH_BUG_HOSTKEYS },
126 { "WinSCP_release_4*,"
127 "WinSCP_release_5.0*,"
128 "WinSCP_release_5.1,"
129 "WinSCP_release_5.1.*,"
130 "WinSCP_release_5.5,"
131 "WinSCP_release_5.5.*,"
132 "WinSCP_release_5.6,"
133 "WinSCP_release_5.6.*,"
134 "WinSCP_release_5.7,"
135 "WinSCP_release_5.7.1,"
136 "WinSCP_release_5.7.2,"
137 "WinSCP_release_5.7.3,"
138 "WinSCP_release_5.7.4",
139 SSH_OLD_DHGEX },
140 { "ConfD-*",
141 SSH_BUG_UTF8TTYMODE },
142 { "Twisted_*", 0 },
143 { "Twisted*", SSH_BUG_DEBUG },
144 { NULL, 0 }
145 };
146
147 /* process table, return first match */
148 for (i = 0; check[i].pat; i++) {
149 if (match_pattern_list(version, check[i].pat, 0) == 1) {
150 debug("match: %s pat %s compat 0x%08x",
151 version, check[i].pat, check[i].bugs);
152 datafellows = check[i].bugs; /* XXX for now */
153 return check[i].bugs;
154 }
155 }
156 debug("no match: %s", version);
157 return 0;
158 }
159
160 #define SEP ","
161 int
proto_spec(const char * spec)162 proto_spec(const char *spec)
163 {
164 char *s, *p, *q;
165 int ret = SSH_PROTO_UNKNOWN;
166
167 if (spec == NULL)
168 return ret;
169 q = s = strdup(spec);
170 if (s == NULL)
171 return ret;
172 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
173 switch (atoi(p)) {
174 case 2:
175 ret |= SSH_PROTO_2;
176 break;
177 default:
178 logit("ignoring bad proto spec: '%s'.", p);
179 break;
180 }
181 }
182 free(s);
183 return ret;
184 }
185
186 char *
compat_cipher_proposal(char * cipher_prop)187 compat_cipher_proposal(char *cipher_prop)
188 {
189 if (!(datafellows & SSH_BUG_BIGENDIANAES))
190 return cipher_prop;
191 debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
192 if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL)
193 fatal("match_filter_blacklist failed");
194 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
195 if (*cipher_prop == '\0')
196 fatal("No supported ciphers found");
197 return cipher_prop;
198 }
199
200 char *
compat_pkalg_proposal(char * pkalg_prop)201 compat_pkalg_proposal(char *pkalg_prop)
202 {
203 if (!(datafellows & SSH_BUG_RSASIGMD5))
204 return pkalg_prop;
205 debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
206 if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL)
207 fatal("match_filter_blacklist failed");
208 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
209 if (*pkalg_prop == '\0')
210 fatal("No supported PK algorithms found");
211 return pkalg_prop;
212 }
213
214 char *
compat_kex_proposal(char * p)215 compat_kex_proposal(char *p)
216 {
217 if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
218 return p;
219 debug2("%s: original KEX proposal: %s", __func__, p);
220 if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
221 if ((p = match_filter_blacklist(p,
222 "curve25519-sha256@libssh.org")) == NULL)
223 fatal("match_filter_blacklist failed");
224 if ((datafellows & SSH_OLD_DHGEX) != 0) {
225 if ((p = match_filter_blacklist(p,
226 "diffie-hellman-group-exchange-sha256,"
227 "diffie-hellman-group-exchange-sha1")) == NULL)
228 fatal("match_filter_blacklist failed");
229 }
230 debug2("%s: compat KEX proposal: %s", __func__, p);
231 if (*p == '\0')
232 fatal("No supported key exchange algorithms found");
233 return p;
234 }
235
236