compat.c

   1 /* $OpenBSD: compat.c,v 1.75 2006/07/26 13:57:17 stevesk 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 <stdlib.h>
  29 #include <string.h>
  30
  31 #include "buffer.h"
  32 #include "packet.h"
  33 #include "xmalloc.h"
  34 #include "compat.h"
  35 #include "log.h"
  36 #include "match.h"
  37
  38 int compat13 = 0;
  39 int compat20 = 0;
  40 int datafellows = 0;
  41
  42 void
  43 enable_compat20(void)
  44 {
  45         debug("Enabling compatibility mode for protocol 2.0");
  46         compat20 = 1;
  47 }
  48 void
  49 enable_compat13(void)
  50 {
  51         debug("Enabling compatibility mode for protocol 1.3");
  52         compat13 = 1;
  53 }
  54 /* datafellows bug compatibility */
  55 void
  56 compat_datafellows(const char *version)
  57 {
  58         int i;
  59         static struct {
  60                 char    *pat;
  61                 int     bugs;
  62         } check[] = {
  63                 { "OpenSSH-2.0*,"
  64                   "OpenSSH-2.1*,"
  65                   "OpenSSH_2.1*,"
  66                   "OpenSSH_2.2*",       SSH_OLD_SESSIONID|SSH_BUG_BANNER|
  67                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  68                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  69                 { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
  70                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  71                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  72                 { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  73                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  74                                         SSH_OLD_FORWARD_ADDR},
  75                 { "OpenSSH_2.5.0p1*,"
  76                   "OpenSSH_2.5.1p1*",
  77                                         SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  78                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  79                                         SSH_OLD_FORWARD_ADDR},
  80                 { "OpenSSH_2.5.0*,"
  81                   "OpenSSH_2.5.1*,"
  82                   "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  83                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  84                 { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  85                                         SSH_OLD_FORWARD_ADDR},
  86                 { "OpenSSH_2.*,"
  87                   "OpenSSH_3.0*,"
  88                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  89                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR },
  90                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  91                 { "OpenSSH*",           0 },
  92                 { "*MindTerm*",         0 },
  93                 { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
  94                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
  95                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
  96                                         SSH_BUG_FIRSTKEX },
  97                 { "2.1 *",              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                 { "2.0.13*,"
 102                   "2.0.14*,"
 103                   "2.0.15*,"
 104                   "2.0.16*,"
 105                   "2.0.17*,"
 106                   "2.0.18*,"
 107                   "2.0.19*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 108                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 109                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 110                                         SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
 111                                         SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
 112                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 113                 { "2.0.11*,"
 114                   "2.0.12*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 115                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 116                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 117                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 118                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
 119                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 120                 { "2.0.*",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 121                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 122                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 123                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 124                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
 125                                         SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
 126                                         SSH_BUG_FIRSTKEX },
 127                 { "2.2.0*,"
 128                   "2.3.0*",             SSH_BUG_HMAC|SSH_BUG_DEBUG|
 129                                         SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
 130                 { "2.3.*",              SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
 131                                         SSH_BUG_FIRSTKEX },
 132                 { "2.4",                SSH_OLD_SESSIONID },    /* Van Dyke */
 133                 { "2.*",                SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX },
 134                 { "3.0.*",              SSH_BUG_DEBUG },
 135                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
 136                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
 137                 { "1.2.18*,"
 138                   "1.2.19*,"
 139                   "1.2.20*,"
 140                   "1.2.21*,"
 141                   "1.2.22*",            SSH_BUG_IGNOREMSG },
 142                 { "1.3.2*",             /* F-Secure */
 143                                         SSH_BUG_IGNOREMSG },
 144                 { "*SSH Compatible Server*",                    /* Netscreen */
 145                                         SSH_BUG_PASSWORDPAD },
 146                 { "*OSU_0*,"
 147                   "OSU_1.0*,"
 148                   "OSU_1.1*,"
 149                   "OSU_1.2*,"
 150                   "OSU_1.3*,"
 151                   "OSU_1.4*,"
 152                   "OSU_1.5alpha1*,"
 153                   "OSU_1.5alpha2*,"
 154                   "OSU_1.5alpha3*",     SSH_BUG_PASSWORDPAD },
 155                 { "*SSH_Version_Mapper*",
 156                                         SSH_BUG_SCANNER },
 157                 { "Probe-*",
 158                                         SSH_BUG_PROBE },
 159                 { NULL,                 0 }
 160         };
 161
 162         /* process table, return first match */
 163         for (i = 0; check[i].pat; i++) {
 164                 if (match_pattern_list(version, check[i].pat,
 165                     strlen(check[i].pat), 0) == 1) {
 166                         debug("match: %s pat %s", version, check[i].pat);
 167                         datafellows = check[i].bugs;
 168                         return;
 169                 }
 170         }
 171         debug("no match: %s", version);
 172 }
 173
 174 #define SEP     ","
 175 int
 176 proto_spec(const char *spec)
 177 {
 178         char *s, *p, *q;
 179         int ret = SSH_PROTO_UNKNOWN;
 180
 181         if (spec == NULL)
 182                 return ret;
 183         q = s = xstrdup(spec);
 184         for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
 185                 switch (atoi(p)) {
 186                 case 1:
 187                         if (ret == SSH_PROTO_UNKNOWN)
 188                                 ret |= SSH_PROTO_1_PREFERRED;
 189                         ret |= SSH_PROTO_1;
 190                         break;
 191                 case 2:
 192                         ret |= SSH_PROTO_2;
 193                         break;
 194                 default:
 195                         logit("ignoring bad proto spec: '%s'.", p);
 196                         break;
 197                 }
 198         }
 199         xfree(s);
 200         return ret;
 201 }
 202
 203 char *
 204 compat_cipher_proposal(char *cipher_prop)
 205 {
 206         Buffer b;
 207         char *orig_prop, *fix_ciphers;
 208         char *cp, *tmp;
 209
 210         if (!(datafellows & SSH_BUG_BIGENDIANAES))
 211                 return(cipher_prop);
 212
 213         buffer_init(&b);
 214         tmp = orig_prop = xstrdup(cipher_prop);
 215         while ((cp = strsep(&tmp, ",")) != NULL) {
 216                 if (strncmp(cp, "aes", 3) != 0) {
 217                         if (buffer_len(&b) > 0)
 218                                 buffer_append(&b, ",", 1);
 219                         buffer_append(&b, cp, strlen(cp));
 220                 }
 221         }
 222         buffer_append(&b, "\0", 1);
 223         fix_ciphers = xstrdup(buffer_ptr(&b));
 224         buffer_free(&b);
 225         xfree(orig_prop);
 226         debug2("Original cipher proposal: %s", cipher_prop);
 227         debug2("Compat cipher proposal: %s", fix_ciphers);
 228         if (!*fix_ciphers)
 229                 fatal("No available ciphers found.");
 230
 231         return(fix_ciphers);
 232 }