Merge branch 'vendor/OPENSSH'
[dragonfly.git] / crypto / openssh / compat.c
1 /* $OpenBSD: compat.c,v 1.85 2014/04/20 02:49:32 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 "buffer.h"
36 #include "packet.h"
37 #include "compat.h"
38 #include "log.h"
39 #include "match.h"
40
41 int compat13 = 0;
42 int compat20 = 0;
43 int datafellows = 0;
44
45 void
46 enable_compat20(void)
47 {
48         if (compat20)
49                 return;
50         debug("Enabling compatibility mode for protocol 2.0");
51         compat20 = 1;
52 }
53 void
54 enable_compat13(void)
55 {
56         debug("Enabling compatibility mode for protocol 1.3");
57         compat13 = 1;
58 }
59 /* datafellows bug compatibility */
60 void
61 compat_datafellows(const char *version)
62 {
63         int i;
64         static struct {
65                 char    *pat;
66                 int     bugs;
67         } check[] = {
68                 { "OpenSSH-2.0*,"
69                   "OpenSSH-2.1*,"
70                   "OpenSSH_2.1*,"
71                   "OpenSSH_2.2*",       SSH_OLD_SESSIONID|SSH_BUG_BANNER|
72                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
73                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
74                 { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
75                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
76                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
77                 { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
78                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
79                                         SSH_OLD_FORWARD_ADDR},
80                 { "OpenSSH_2.5.0p1*,"
81                   "OpenSSH_2.5.1p1*",
82                                         SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
83                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
84                                         SSH_OLD_FORWARD_ADDR},
85                 { "OpenSSH_2.5.0*,"
86                   "OpenSSH_2.5.1*,"
87                   "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
88                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
89                 { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
90                                         SSH_OLD_FORWARD_ADDR},
91                 { "OpenSSH_2.*,"
92                   "OpenSSH_3.0*,"
93                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
94                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR },
95                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
96                 { "OpenSSH_4*",         0 },
97                 { "OpenSSH_5*",         SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
98                 { "OpenSSH_6.6.1*",     SSH_NEW_OPENSSH},
99                 { "OpenSSH_6.5*,"
100                   "OpenSSH_6.6*",       SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
101                 { "OpenSSH*",           SSH_NEW_OPENSSH },
102                 { "*MindTerm*",         0 },
103                 { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
104                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
105                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
106                                         SSH_BUG_FIRSTKEX },
107                 { "2.1 *",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
108                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
109                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
110                                         SSH_BUG_FIRSTKEX },
111                 { "2.0.13*,"
112                   "2.0.14*,"
113                   "2.0.15*,"
114                   "2.0.16*,"
115                   "2.0.17*,"
116                   "2.0.18*,"
117                   "2.0.19*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
118                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
119                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
120                                         SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
121                                         SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
122                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
123                 { "2.0.11*,"
124                   "2.0.12*",            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_DUMMYCHAN|SSH_BUG_FIRSTKEX },
130                 { "2.0.*",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
131                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
132                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
133                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
134                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
135                                         SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
136                                         SSH_BUG_FIRSTKEX },
137                 { "2.2.0*,"
138                   "2.3.0*",             SSH_BUG_HMAC|SSH_BUG_DEBUG|
139                                         SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
140                 { "2.3.*",              SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
141                                         SSH_BUG_FIRSTKEX },
142                 { "2.4",                SSH_OLD_SESSIONID },    /* Van Dyke */
143                 { "2.*",                SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
144                                         SSH_BUG_RFWD_ADDR },
145                 { "3.0.*",              SSH_BUG_DEBUG },
146                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
147                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
148                 { "1.2.18*,"
149                   "1.2.19*,"
150                   "1.2.20*,"
151                   "1.2.21*,"
152                   "1.2.22*",            SSH_BUG_IGNOREMSG },
153                 { "1.3.2*",             /* F-Secure */
154                                         SSH_BUG_IGNOREMSG },
155                 { "*SSH Compatible Server*",                    /* Netscreen */
156                                         SSH_BUG_PASSWORDPAD },
157                 { "*OSU_0*,"
158                   "OSU_1.0*,"
159                   "OSU_1.1*,"
160                   "OSU_1.2*,"
161                   "OSU_1.3*,"
162                   "OSU_1.4*,"
163                   "OSU_1.5alpha1*,"
164                   "OSU_1.5alpha2*,"
165                   "OSU_1.5alpha3*",     SSH_BUG_PASSWORDPAD },
166                 { "*SSH_Version_Mapper*",
167                                         SSH_BUG_SCANNER },
168                 { "Probe-*",
169                                         SSH_BUG_PROBE },
170                 { NULL,                 0 }
171         };
172
173         /* process table, return first match */
174         for (i = 0; check[i].pat; i++) {
175                 if (match_pattern_list(version, check[i].pat,
176                     strlen(check[i].pat), 0) == 1) {
177                         datafellows = check[i].bugs;
178                         /* Check to see if the remote side is OpenSSH and not HPN */
179                         if(strstr(version,"OpenSSH") != NULL)
180                         {
181                                 if (strstr(version,"hpn") == NULL)
182                                 {
183                                         datafellows |= SSH_BUG_LARGEWINDOW;
184                                         debug("Remote is NON-HPN aware");
185                                 }
186                         }
187                         debug("match: %s pat %s compat 0x%08x",
188                             version, check[i].pat, datafellows);
189                         return;
190                 }
191         }
192         debug("no match: %s", version);
193 }
194
195 #define SEP     ","
196 int
197 proto_spec(const char *spec)
198 {
199         char *s, *p, *q;
200         int ret = SSH_PROTO_UNKNOWN;
201
202         if (spec == NULL)
203                 return ret;
204         q = s = xstrdup(spec);
205         for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
206                 switch (atoi(p)) {
207                 case 1:
208                         if (ret == SSH_PROTO_UNKNOWN)
209                                 ret |= SSH_PROTO_1_PREFERRED;
210                         ret |= SSH_PROTO_1;
211                         break;
212                 case 2:
213                         ret |= SSH_PROTO_2;
214                         break;
215                 default:
216                         logit("ignoring bad proto spec: '%s'.", p);
217                         break;
218                 }
219         }
220         free(s);
221         return ret;
222 }
223
224 /*
225  * Filters a proposal string, excluding any algorithm matching the 'filter'
226  * pattern list.
227  */
228 static char *
229 filter_proposal(char *proposal, const char *filter)
230 {
231         Buffer b;
232         char *orig_prop, *fix_prop;
233         char *cp, *tmp;
234
235         buffer_init(&b);
236         tmp = orig_prop = xstrdup(proposal);
237         while ((cp = strsep(&tmp, ",")) != NULL) {
238                 if (match_pattern_list(cp, filter, strlen(cp), 0) != 1) {
239                         if (buffer_len(&b) > 0)
240                                 buffer_append(&b, ",", 1);
241                         buffer_append(&b, cp, strlen(cp));
242                 } else
243                         debug2("Compat: skipping algorithm \"%s\"", cp);
244         }
245         buffer_append(&b, "\0", 1);
246         fix_prop = xstrdup(buffer_ptr(&b));
247         buffer_free(&b);
248         free(orig_prop);
249
250         return fix_prop;
251 }
252
253 char *
254 compat_cipher_proposal(char *cipher_prop)
255 {
256         if (!(datafellows & SSH_BUG_BIGENDIANAES))
257                 return cipher_prop;
258         debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
259         cipher_prop = filter_proposal(cipher_prop, "aes*");
260         debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
261         if (*cipher_prop == '\0')
262                 fatal("No supported ciphers found");
263         return cipher_prop;
264 }
265
266 char *
267 compat_pkalg_proposal(char *pkalg_prop)
268 {
269         if (!(datafellows & SSH_BUG_RSASIGMD5))
270                 return pkalg_prop;
271         debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
272         pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa");
273         debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
274         if (*pkalg_prop == '\0')
275                 fatal("No supported PK algorithms found");
276         return pkalg_prop;
277 }
278
279 char *
280 compat_kex_proposal(char *kex_prop)
281 {
282         if (!(datafellows & SSH_BUG_CURVE25519PAD))
283                 return kex_prop;
284         debug2("%s: original KEX proposal: %s", __func__, kex_prop);
285         kex_prop = filter_proposal(kex_prop, "curve25519-sha256@libssh.org");
286         debug2("%s: compat KEX proposal: %s", __func__, kex_prop);
287         if (*kex_prop == '\0')
288                 fatal("No supported key exchange algorithms found");
289         return kex_prop;
290 }
291