compat.c

   1 /* $OpenBSD: compat.c,v 1.76 2006/08/03 03:34:42 deraadt 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         debug("Enabling compatibility mode for protocol 2.0");
  49         compat20 = 1;
  50 }
  51 void
  52 enable_compat13(void)
  53 {
  54         debug("Enabling compatibility mode for protocol 1.3");
  55         compat13 = 1;
  56 }
  57 /* datafellows bug compatibility */
  58 void
  59 compat_datafellows(const char *version)
  60 {
  61         int i;
  62         static struct {
  63                 char    *pat;
  64                 int     bugs;
  65         } check[] = {
  66                 { "OpenSSH-2.0*,"
  67                   "OpenSSH-2.1*,"
  68                   "OpenSSH_2.1*,"
  69                   "OpenSSH_2.2*",       SSH_OLD_SESSIONID|SSH_BUG_BANNER|
  70                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  71                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  72                 { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
  73                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  74                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  75                 { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  76                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  77                                         SSH_OLD_FORWARD_ADDR},
  78                 { "OpenSSH_2.5.0p1*,"
  79                   "OpenSSH_2.5.1p1*",
  80                                         SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  81                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  82                                         SSH_OLD_FORWARD_ADDR},
  83                 { "OpenSSH_2.5.0*,"
  84                   "OpenSSH_2.5.1*,"
  85                   "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  86                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  87                 { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  88                                         SSH_OLD_FORWARD_ADDR},
  89                 { "OpenSSH_2.*,"
  90                   "OpenSSH_3.0*,"
  91                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  92                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR },
  93                 { "Sun_SSH_1.0*",       SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
  94                 { "OpenSSH*",           0 },
  95                 { "*MindTerm*",         0 },
  96                 { "2.1.0*",             SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
  97                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
  98                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
  99                                         SSH_BUG_FIRSTKEX },
 100                 { "2.1 *",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 101                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 102                                         SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
 103                                         SSH_BUG_FIRSTKEX },
 104                 { "2.0.13*,"
 105                   "2.0.14*,"
 106                   "2.0.15*,"
 107                   "2.0.16*,"
 108                   "2.0.17*,"
 109                   "2.0.18*,"
 110                   "2.0.19*",            SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 111                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 112                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 113                                         SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
 114                                         SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
 115                                         SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 116                 { "2.0.11*,"
 117                   "2.0.12*",            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_DUMMYCHAN|SSH_BUG_FIRSTKEX },
 123                 { "2.0.*",              SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
 124                                         SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
 125                                         SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
 126                                         SSH_BUG_PKAUTH|SSH_BUG_PKOK|
 127                                         SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
 128                                         SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
 129                                         SSH_BUG_FIRSTKEX },
 130                 { "2.2.0*,"
 131                   "2.3.0*",             SSH_BUG_HMAC|SSH_BUG_DEBUG|
 132                                         SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
 133                 { "2.3.*",              SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
 134                                         SSH_BUG_FIRSTKEX },
 135                 { "2.4",                SSH_OLD_SESSIONID },    /* Van Dyke */
 136                 { "2.*",                SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX },
 137                 { "3.0.*",              SSH_BUG_DEBUG },
 138                 { "3.0 SecureCRT*",     SSH_OLD_SESSIONID },
 139                 { "1.7 SecureFX*",      SSH_OLD_SESSIONID },
 140                 { "1.2.18*,"
 141                   "1.2.19*,"
 142                   "1.2.20*,"
 143                   "1.2.21*,"
 144                   "1.2.22*",            SSH_BUG_IGNOREMSG },
 145                 { "1.3.2*",             /* F-Secure */
 146                                         SSH_BUG_IGNOREMSG },
 147                 { "*SSH Compatible Server*",                    /* Netscreen */
 148                                         SSH_BUG_PASSWORDPAD },
 149                 { "*OSU_0*,"
 150                   "OSU_1.0*,"
 151                   "OSU_1.1*,"
 152                   "OSU_1.2*,"
 153                   "OSU_1.3*,"
 154                   "OSU_1.4*,"
 155                   "OSU_1.5alpha1*,"
 156                   "OSU_1.5alpha2*,"
 157                   "OSU_1.5alpha3*",     SSH_BUG_PASSWORDPAD },
 158                 { "*SSH_Version_Mapper*",
 159                                         SSH_BUG_SCANNER },
 160                 { "Probe-*",
 161                                         SSH_BUG_PROBE },
 162                 { NULL,                 0 }
 163         };
 164
 165         /* process table, return first match */
 166         for (i = 0; check[i].pat; i++) {
 167                 if (match_pattern_list(version, check[i].pat,
 168                     strlen(check[i].pat), 0) == 1) {
 169                         debug("match: %s pat %s", version, check[i].pat);
 170                         datafellows = check[i].bugs;
 171                         return;
 172                 }
 173         }
 174         debug("no match: %s", version);
 175 }
 176
 177 #define SEP     ","
 178 int
 179 proto_spec(const char *spec)
 180 {
 181         char *s, *p, *q;
 182         int ret = SSH_PROTO_UNKNOWN;
 183
 184         if (spec == NULL)
 185                 return ret;
 186         q = s = xstrdup(spec);
 187         for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
 188                 switch (atoi(p)) {
 189                 case 1:
 190                         if (ret == SSH_PROTO_UNKNOWN)
 191                                 ret |= SSH_PROTO_1_PREFERRED;
 192                         ret |= SSH_PROTO_1;
 193                         break;
 194                 case 2:
 195                         ret |= SSH_PROTO_2;
 196                         break;
 197                 default:
 198                         logit("ignoring bad proto spec: '%s'.", p);
 199                         break;
 200                 }
 201         }
 202         xfree(s);
 203         return ret;
 204 }
 205
 206 char *
 207 compat_cipher_proposal(char *cipher_prop)
 208 {
 209         Buffer b;
 210         char *orig_prop, *fix_ciphers;
 211         char *cp, *tmp;
 212
 213         if (!(datafellows & SSH_BUG_BIGENDIANAES))
 214                 return(cipher_prop);
 215
 216         buffer_init(&b);
 217         tmp = orig_prop = xstrdup(cipher_prop);
 218         while ((cp = strsep(&tmp, ",")) != NULL) {
 219                 if (strncmp(cp, "aes", 3) != 0) {
 220                         if (buffer_len(&b) > 0)
 221                                 buffer_append(&b, ",", 1);
 222                         buffer_append(&b, cp, strlen(cp));
 223                 }
 224         }
 225         buffer_append(&b, "\0", 1);
 226         fix_ciphers = xstrdup(buffer_ptr(&b));
 227         buffer_free(&b);
 228         xfree(orig_prop);
 229         debug2("Original cipher proposal: %s", cipher_prop);
 230         debug2("Compat cipher proposal: %s", fix_ciphers);
 231         if (!*fix_ciphers)
 232                 fatal("No available ciphers found.");
 233
 234         return(fix_ciphers);
 235 }