1 /* $OpenBSD: compat.c,v 1.104 2017/07/25 09:22:25 dtucker 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 #include "kex.h" 39 40 int datafellows = 0; 41 42 /* datafellows bug compatibility */ 43 u_int 44 compat_datafellows(const char *version) 45 { 46 int i; 47 static struct { 48 char *pat; 49 int bugs; 50 } check[] = { 51 { "OpenSSH-2.0*," 52 "OpenSSH-2.1*," 53 "OpenSSH_2.1*," 54 "OpenSSH_2.2*", SSH_OLD_SESSIONID|SSH_BUG_BANNER| 55 SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 56 SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 57 { "OpenSSH_2.3.0*", SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES| 58 SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 59 SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 60 { "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| 61 SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 62 SSH_OLD_FORWARD_ADDR}, 63 { "OpenSSH_2.5.0p1*," 64 "OpenSSH_2.5.1p1*", 65 SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| 66 SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 67 SSH_OLD_FORWARD_ADDR}, 68 { "OpenSSH_2.5.0*," 69 "OpenSSH_2.5.1*," 70 "OpenSSH_2.5.2*", SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 71 SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 72 { "OpenSSH_2.5.3*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 73 SSH_OLD_FORWARD_ADDR}, 74 { "OpenSSH_2.*," 75 "OpenSSH_3.0*," 76 "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 77 { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR }, 78 { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF}, 79 { "OpenSSH_4*", 0 }, 80 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, 81 { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH}, 82 { "OpenSSH_6.5*," 83 "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD}, 84 { "OpenSSH*", SSH_NEW_OPENSSH }, 85 { "*MindTerm*", 0 }, 86 { "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 87 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 88 SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| 89 SSH_BUG_FIRSTKEX }, 90 { "2.1 *", 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 { "2.0.13*," 95 "2.0.14*," 96 "2.0.15*," 97 "2.0.16*," 98 "2.0.17*," 99 "2.0.18*," 100 "2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 101 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 102 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 103 SSH_BUG_PKOK|SSH_BUG_RSASIGMD5| 104 SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE| 105 SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 106 { "2.0.11*," 107 "2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 108 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 109 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 110 SSH_BUG_PKAUTH|SSH_BUG_PKOK| 111 SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 112 SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 113 { "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 114 SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 115 SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 116 SSH_BUG_PKAUTH|SSH_BUG_PKOK| 117 SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 118 SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN| 119 SSH_BUG_FIRSTKEX }, 120 { "2.2.0*," 121 "2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG| 122 SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX }, 123 { "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5| 124 SSH_BUG_FIRSTKEX }, 125 { "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */ 126 { "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX| 127 SSH_BUG_RFWD_ADDR }, 128 { "3.0.*", SSH_BUG_DEBUG }, 129 { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 130 { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 131 { "1.2.18*," 132 "1.2.19*," 133 "1.2.20*," 134 "1.2.21*," 135 "1.2.22*", SSH_BUG_IGNOREMSG }, 136 { "1.3.2*", /* F-Secure */ 137 SSH_BUG_IGNOREMSG }, 138 { "Cisco-1.*", SSH_BUG_DHGEX_LARGE| 139 SSH_BUG_HOSTKEYS }, 140 { "*SSH Compatible Server*", /* Netscreen */ 141 SSH_BUG_PASSWORDPAD }, 142 { "*OSU_0*," 143 "OSU_1.0*," 144 "OSU_1.1*," 145 "OSU_1.2*," 146 "OSU_1.3*," 147 "OSU_1.4*," 148 "OSU_1.5alpha1*," 149 "OSU_1.5alpha2*," 150 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 151 { "*SSH_Version_Mapper*", 152 SSH_BUG_SCANNER }, 153 { "PuTTY_Local:*," /* dev versions < Sep 2014 */ 154 "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */ 155 "PuTTY_Release_0.5*," /* 0.58-0.59 */ 156 "PuTTY_Release_0.60*," 157 "PuTTY_Release_0.61*," 158 "PuTTY_Release_0.62*," 159 "PuTTY_Release_0.63*," 160 "PuTTY_Release_0.64*", 161 SSH_OLD_DHGEX }, 162 { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */ 163 { "Probe-*", 164 SSH_BUG_PROBE }, 165 { "TeraTerm SSH*," 166 "TTSSH/1.5.*," 167 "TTSSH/2.1*," 168 "TTSSH/2.2*," 169 "TTSSH/2.3*," 170 "TTSSH/2.4*," 171 "TTSSH/2.5*," 172 "TTSSH/2.6*," 173 "TTSSH/2.70*," 174 "TTSSH/2.71*," 175 "TTSSH/2.72*", SSH_BUG_HOSTKEYS }, 176 { "WinSCP_release_4*," 177 "WinSCP_release_5.0*," 178 "WinSCP_release_5.1," 179 "WinSCP_release_5.1.*," 180 "WinSCP_release_5.5," 181 "WinSCP_release_5.5.*," 182 "WinSCP_release_5.6," 183 "WinSCP_release_5.6.*," 184 "WinSCP_release_5.7," 185 "WinSCP_release_5.7.1," 186 "WinSCP_release_5.7.2," 187 "WinSCP_release_5.7.3," 188 "WinSCP_release_5.7.4", 189 SSH_OLD_DHGEX }, 190 { NULL, 0 } 191 }; 192 193 /* process table, return first match */ 194 for (i = 0; check[i].pat; i++) { 195 if (match_pattern_list(version, check[i].pat, 0) == 1) { 196 debug("match: %s pat %s compat 0x%08x", 197 version, check[i].pat, check[i].bugs); 198 datafellows = check[i].bugs; /* XXX for now */ 199 return check[i].bugs; 200 } 201 } 202 debug("no match: %s", version); 203 return 0; 204 } 205 206 #define SEP "," 207 int 208 proto_spec(const char *spec) 209 { 210 char *s, *p, *q; 211 int ret = SSH_PROTO_UNKNOWN; 212 213 if (spec == NULL) 214 return ret; 215 q = s = strdup(spec); 216 if (s == NULL) 217 return ret; 218 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 219 switch (atoi(p)) { 220 case 2: 221 ret |= SSH_PROTO_2; 222 break; 223 default: 224 logit("ignoring bad proto spec: '%s'.", p); 225 break; 226 } 227 } 228 free(s); 229 return ret; 230 } 231 232 char * 233 compat_cipher_proposal(char *cipher_prop) 234 { 235 if (!(datafellows & SSH_BUG_BIGENDIANAES)) 236 return cipher_prop; 237 debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 238 if ((cipher_prop = match_filter_list(cipher_prop, "aes*")) == NULL) 239 fatal("match_filter_list failed"); 240 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 241 if (*cipher_prop == '\0') 242 fatal("No supported ciphers found"); 243 return cipher_prop; 244 } 245 246 char * 247 compat_pkalg_proposal(char *pkalg_prop) 248 { 249 if (!(datafellows & SSH_BUG_RSASIGMD5)) 250 return pkalg_prop; 251 debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 252 if ((pkalg_prop = match_filter_list(pkalg_prop, "ssh-rsa")) == NULL) 253 fatal("match_filter_list failed"); 254 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 255 if (*pkalg_prop == '\0') 256 fatal("No supported PK algorithms found"); 257 return pkalg_prop; 258 } 259 260 char * 261 compat_kex_proposal(char *p) 262 { 263 if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) 264 return p; 265 debug2("%s: original KEX proposal: %s", __func__, p); 266 if ((datafellows & SSH_BUG_CURVE25519PAD) != 0) 267 if ((p = match_filter_list(p, 268 "curve25519-sha256@libssh.org")) == NULL) 269 fatal("match_filter_list failed"); 270 if ((datafellows & SSH_OLD_DHGEX) != 0) { 271 if ((p = match_filter_list(p, 272 "diffie-hellman-group-exchange-sha256," 273 "diffie-hellman-group-exchange-sha1")) == NULL) 274 fatal("match_filter_list failed"); 275 } 276 debug2("%s: compat KEX proposal: %s", __func__, p); 277 if (*p == '\0') 278 fatal("No supported key exchange algorithms found"); 279 return p; 280 } 281 282