1 /* $OpenBSD: compat.c,v 1.82 2013/12/30 23:52:27 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 <sys/types.h> 27 28 #include <stdlib.h> 29 #include <string.h> 30 #include <stdarg.h> 31 32 #include "xmalloc.h" 33 #include "buffer.h" 34 #include "packet.h" 35 #include "compat.h" 36 #include "log.h" 37 #include "match.h" 38 39 int compat13 = 0; 40 int compat20 = 0; 41 int datafellows = 0; 42 43 void 44 enable_compat20(void) 45 { 46 if (compat20) 47 return; 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_4*", 0 }, 95 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, 96 { "OpenSSH*", SSH_NEW_OPENSSH }, 97 { "*MindTerm*", 0 }, 98 { "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 99 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 100 SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| 101 SSH_BUG_FIRSTKEX }, 102 { "2.1 *", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 103 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 104 SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| 105 SSH_BUG_FIRSTKEX }, 106 { "2.0.13*," 107 "2.0.14*," 108 "2.0.15*," 109 "2.0.16*," 110 "2.0.17*," 111 "2.0.18*," 112 "2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 113 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 114 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 115 SSH_BUG_PKOK|SSH_BUG_RSASIGMD5| 116 SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE| 117 SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 118 { "2.0.11*," 119 "2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 120 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 121 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 122 SSH_BUG_PKAUTH|SSH_BUG_PKOK| 123 SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 124 SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 125 { "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 126 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 127 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 128 SSH_BUG_PKAUTH|SSH_BUG_PKOK| 129 SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 130 SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN| 131 SSH_BUG_FIRSTKEX }, 132 { "2.2.0*," 133 "2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG| 134 SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX }, 135 { "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5| 136 SSH_BUG_FIRSTKEX }, 137 { "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */ 138 { "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX| 139 SSH_BUG_RFWD_ADDR }, 140 { "3.0.*", SSH_BUG_DEBUG }, 141 { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 142 { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 143 { "1.2.18*," 144 "1.2.19*," 145 "1.2.20*," 146 "1.2.21*," 147 "1.2.22*", SSH_BUG_IGNOREMSG }, 148 { "1.3.2*", /* F-Secure */ 149 SSH_BUG_IGNOREMSG }, 150 { "*SSH Compatible Server*", /* Netscreen */ 151 SSH_BUG_PASSWORDPAD }, 152 { "*OSU_0*," 153 "OSU_1.0*," 154 "OSU_1.1*," 155 "OSU_1.2*," 156 "OSU_1.3*," 157 "OSU_1.4*," 158 "OSU_1.5alpha1*," 159 "OSU_1.5alpha2*," 160 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 161 { "*SSH_Version_Mapper*", 162 SSH_BUG_SCANNER }, 163 { "Probe-*", 164 SSH_BUG_PROBE }, 165 { NULL, 0 } 166 }; 167 168 /* process table, return first match */ 169 for (i = 0; check[i].pat; i++) { 170 if (match_pattern_list(version, check[i].pat, 171 strlen(check[i].pat), 0) == 1) { 172 datafellows = check[i].bugs; 173 debug("match: %s pat %s compat 0x%08x", 174 version, check[i].pat, datafellows); 175 return; 176 } 177 } 178 debug("no match: %s", version); 179 } 180 181 #define SEP "," 182 int 183 proto_spec(const char *spec) 184 { 185 char *s, *p, *q; 186 int ret = SSH_PROTO_UNKNOWN; 187 188 if (spec == NULL) 189 return ret; 190 q = s = xstrdup(spec); 191 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 192 switch (atoi(p)) { 193 case 1: 194 if (ret == SSH_PROTO_UNKNOWN) 195 ret |= SSH_PROTO_1_PREFERRED; 196 ret |= SSH_PROTO_1; 197 break; 198 case 2: 199 ret |= SSH_PROTO_2; 200 break; 201 default: 202 logit("ignoring bad proto spec: '%s'.", p); 203 break; 204 } 205 } 206 free(s); 207 return ret; 208 } 209 210 /* 211 * Filters a proposal string, excluding any algorithm matching the 'filter' 212 * pattern list. 213 */ 214 static char * 215 filter_proposal(char *proposal, const char *filter) 216 { 217 Buffer b; 218 char *orig_prop, *fix_prop; 219 char *cp, *tmp; 220 221 buffer_init(&b); 222 tmp = orig_prop = xstrdup(proposal); 223 while ((cp = strsep(&tmp, ",")) != NULL) { 224 if (match_pattern_list(cp, filter, strlen(cp), 0) != 1) { 225 if (buffer_len(&b) > 0) 226 buffer_append(&b, ",", 1); 227 buffer_append(&b, cp, strlen(cp)); 228 } else 229 debug2("Compat: skipping algorithm \"%s\"", cp); 230 } 231 buffer_append(&b, "\0", 1); 232 fix_prop = xstrdup(buffer_ptr(&b)); 233 buffer_free(&b); 234 free(orig_prop); 235 236 return fix_prop; 237 } 238 239 char * 240 compat_cipher_proposal(char *cipher_prop) 241 { 242 if (!(datafellows & SSH_BUG_BIGENDIANAES)) 243 return cipher_prop; 244 debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 245 cipher_prop = filter_proposal(cipher_prop, "aes*"); 246 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 247 if (*cipher_prop == '\0') 248 fatal("No supported ciphers found"); 249 return cipher_prop; 250 } 251 252 253 char * 254 compat_pkalg_proposal(char *pkalg_prop) 255 { 256 if (!(datafellows & SSH_BUG_RSASIGMD5)) 257 return pkalg_prop; 258 debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 259 pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa"); 260 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 261 if (*pkalg_prop == '\0') 262 fatal("No supported PK algorithms found"); 263 return pkalg_prop; 264 } 265 266