compat.c

   1 /* $OpenBSD: compat.c,v 1.73 2006/03/25 13:17:01 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 "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|SSH_OLD_FORWARD_ADDR},
  66                 { "OpenSSH_2.3.0*",     SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
  67                                         SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  68                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  69                 { "OpenSSH_2.3.*",      SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  70                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  71                                         SSH_OLD_FORWARD_ADDR},
  72                 { "OpenSSH_2.5.0p1*,"
  73                   "OpenSSH_2.5.1p1*",
  74                                         SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
  75                                         SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  76                                         SSH_OLD_FORWARD_ADDR},
  77                 { "OpenSSH_2.5.0*,"
  78                   "OpenSSH_2.5.1*,"
  79                   "OpenSSH_2.5.2*",     SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
  80                                         SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  81                 { "OpenSSH_2.5.3*",     SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
  82                                         SSH_OLD_FORWARD_ADDR},
  83                 { "OpenSSH_2.*,"
  84                   "OpenSSH_3.0*,"
  85                   "OpenSSH_3.1*",       SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
  86                 { "OpenSSH_3.*",        SSH_OLD_FORWARD_ADDR },
  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 },
 139                 { "1.3.2*",             /* F-Secure */
 140                                         SSH_BUG_IGNOREMSG },
 141                 { "*SSH Compatible Server*",                    /* Netscreen */
 142                                         SSH_BUG_PASSWORDPAD },
 143                 { "*OSU_0*,"
 144                   "OSU_1.0*,"
 145                   "OSU_1.1*,"
 146                   "OSU_1.2*,"
 147                   "OSU_1.3*,"
 148                   "OSU_1.4*,"
 149                   "OSU_1.5alpha1*,"
 150                   "OSU_1.5alpha2*,"
 151                   "OSU_1.5alpha3*",     SSH_BUG_PASSWORDPAD },
 152                 { "*SSH_Version_Mapper*",
 153                                         SSH_BUG_SCANNER },
 154                 { "Probe-*",
 155                                         SSH_BUG_PROBE },
 156                 { NULL,                 0 }
 157         };
 158
 159         /* process table, return first match */
 160         for (i = 0; check[i].pat; i++) {
 161                 if (match_pattern_list(version, check[i].pat,
 162                     strlen(check[i].pat), 0) == 1) {
 163                         debug("match: %s pat %s", version, check[i].pat);
 164                         datafellows = check[i].bugs;
 165                         return;
 166                 }
 167         }
 168         debug("no match: %s", version);
 169 }
 170
 171 #define SEP     ","
 172 int
 173 proto_spec(const char *spec)
 174 {
 175         char *s, *p, *q;
 176         int ret = SSH_PROTO_UNKNOWN;
 177
 178         if (spec == NULL)
 179                 return ret;
 180         q = s = xstrdup(spec);
 181         for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
 182                 switch (atoi(p)) {
 183                 case 1:
 184                         if (ret == SSH_PROTO_UNKNOWN)
 185                                 ret |= SSH_PROTO_1_PREFERRED;
 186                         ret |= SSH_PROTO_1;
 187                         break;
 188                 case 2:
 189                         ret |= SSH_PROTO_2;
 190                         break;
 191                 default:
 192                         logit("ignoring bad proto spec: '%s'.", p);
 193                         break;
 194                 }
 195         }
 196         xfree(s);
 197         return ret;
 198 }
 199
 200 char *
 201 compat_cipher_proposal(char *cipher_prop)
 202 {
 203         Buffer b;
 204         char *orig_prop, *fix_ciphers;
 205         char *cp, *tmp;
 206
 207         if (!(datafellows & SSH_BUG_BIGENDIANAES))
 208                 return(cipher_prop);
 209
 210         buffer_init(&b);
 211         tmp = orig_prop = xstrdup(cipher_prop);
 212         while ((cp = strsep(&tmp, ",")) != NULL) {
 213                 if (strncmp(cp, "aes", 3) != 0) {
 214                         if (buffer_len(&b) > 0)
 215                                 buffer_append(&b, ",", 1);
 216                         buffer_append(&b, cp, strlen(cp));
 217                 }
 218         }
 219         buffer_append(&b, "\0", 1);
 220         fix_ciphers = xstrdup(buffer_ptr(&b));
 221         buffer_free(&b);
 222         xfree(orig_prop);
 223         debug2("Original cipher proposal: %s", cipher_prop);
 224         debug2("Compat cipher proposal: %s", fix_ciphers);
 225         if (!*fix_ciphers)
 226                 fatal("No available ciphers found.");
 227
 228         return(fix_ciphers);
 229 }