compat.c

   1 /*
   2  * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  *
  13  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  14  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  15  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  16  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  17  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  18  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  19  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  20  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  21  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  22  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  23  */
  24
  25 #include "includes.h"
  26 RCSID("$OpenBSD: compat.c,v 1.68 2003/08/22 10:56:09 markus Exp $");
  27
  28 #include "buffer.h"
  29 #include "packet.h"
  30 #include "xmalloc.h"
  31 #include "compat.h"
  32 #include "log.h"
  33 #include "match.h"
  34
  35 int compat13 = 0;
  36 int compat20 = 0;
  37 int datafellows = 0;
  38
  39 void
  40 enable_compat20(void)
  41 {
  42         debug("Enabling compatibility mode for protocol 2.0");
  43         compat20 = 1;
  44 }
  45 void
  46 enable_compat13(void)
  47 {
  48         debug("Enabling compatibility mode for protocol 1.3");
  49         compat13 = 1;
  50 }
  51 /* datafellows bug compatibility */
  52 void
  53 compat_datafellows(const char *version)
  54 {
  55         int i;
  56         static struct {
  57                 char    *pat;
  58                 int     bugs;
  59         } check[] = {
  60                 { "OpenSSH-2.0*,"
  61                   "OpenSSH-2.1*,"
  62                   "OpenSSH_2.1*,"
  63                   "OpenSSH_2.2*",       SSH_OLD_SESSIONID|SSH_BUG_BANNER|
  64                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  65                                         SSH_BUG_EXTEOF},
  66                 { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
  67                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  68                                         SSH_BUG_EXTEOF},
  69                 { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  70                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  71                 { "OpenSSH_2.5.0p1*,"
  72                   "OpenSSH_2.5.1p1*",
  73                                         SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  74                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  75                 { "OpenSSH_2.5.0*,"
  76                   "OpenSSH_2.5.1*,"
  77                   "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  78                                         SSH_BUG_EXTEOF},
  79                 { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  80                 { "OpenSSH_2.*,"
  81                   "OpenSSH_3.0*,"
  82                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_BUG_GSSAPI_BER},
  83                 { "OpenSSH_3.2*,"
  84                   "OpenSSH_3.3*,"
  85                   "OpenSSH_3.4*,"
  86                   "OpenSSH_3.5*",       SSH_BUG_GSSAPI_BER},
  87                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  88                 { "OpenSSH*",           0 },
  89                 { "*MindTerm*",         0 },
  90                 { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
  91                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
  92                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
  93                                         SSH_BUG_FIRSTKEX },
  94                 { "2.1 *",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
  95                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
  96                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
  97                                         SSH_BUG_FIRSTKEX },
  98                 { "2.0.13*,"
  99                   "2.0.14*,"
 100                   "2.0.15*,"
 101                   "2.0.16*,"
 102                   "2.0.17*,"
 103                   "2.0.18*,"
 104                   "2.0.19*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 105                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 106                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 107                                         SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
 108                                         SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
 109                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 110                 { "2.0.11*,"
 111                   "2.0.12*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 112                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 113                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 114                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 115                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
 116                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 117                 { "2.0.*",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 118                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 119                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 120                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 121                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
 122                                         SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
 123                                         SSH_BUG_FIRSTKEX },
 124                 { "2.2.0*,"
 125                   "2.3.0*",             SSH_BUG_HMAC|SSH_BUG_DEBUG|
 126                                         SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
 127                 { "2.3.*",              SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
 128                                         SSH_BUG_FIRSTKEX },
 129                 { "2.4",                SSH_OLD_SESSIONID },    /* Van Dyke */
 130                 { "2.*",                SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX },
 131                 { "3.0.*",              SSH_BUG_DEBUG },
 132                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
 133                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
 134                 { "1.2.18*,"
 135                   "1.2.19*,"
 136                   "1.2.20*,"
 137                   "1.2.21*,"
 138                   "1.2.22*",            SSH_BUG_IGNOREMSG|SSH_BUG_K5USER },
 139                 { "1.3.2*",             /* F-Secure */
 140                                         SSH_BUG_IGNOREMSG|SSH_BUG_K5USER },
 141                 { "1.2.1*,"
 142                   "1.2.2*,"
 143                   "1.2.3*",             SSH_BUG_K5USER },
 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 }