1 /* $OpenBSD: compat.c,v 1.113 2018/08/13 02:41:05 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 <sys/types.h> 29 30 #include <stdlib.h> 31 #include <string.h> 32 #include <stdarg.h> 33 34 #include "xmalloc.h" 35 #include "packet.h" 36 #include "compat.h" 37 #include "log.h" 38 #include "match.h" 39 #include "kex.h" 40 41 int datafellows = 0; 42 43 /* datafellows bug compatibility */ 44 u_int 45 compat_datafellows(const char *version) 46 { 47 int i; 48 static struct { 49 char *pat; 50 int bugs; 51 } check[] = { 52 { "OpenSSH_2.*," 53 "OpenSSH_3.0*," 54 "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR| 55 SSH_BUG_SIGTYPE}, 56 { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE }, 57 { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 58 SSH_BUG_SIGTYPE}, 59 { "OpenSSH_2*," 60 "OpenSSH_3*," 61 "OpenSSH_4*", SSH_BUG_SIGTYPE }, 62 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT| 63 SSH_BUG_SIGTYPE}, 64 { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, 65 { "OpenSSH_6.5*," 66 "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD| 67 SSH_BUG_SIGTYPE}, 68 { "OpenSSH_7.0*," 69 "OpenSSH_7.1*," 70 "OpenSSH_7.2*," 71 "OpenSSH_7.3*," 72 "OpenSSH_7.4*," 73 "OpenSSH_7.5*," 74 "OpenSSH_7.6*," 75 "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, 76 { "OpenSSH*", SSH_NEW_OPENSSH }, 77 { "*MindTerm*", 0 }, 78 { "3.0.*", SSH_BUG_DEBUG }, 79 { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 80 { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 81 { "1.2.18*," 82 "1.2.19*," 83 "1.2.20*," 84 "1.2.21*," 85 "1.2.22*", SSH_BUG_IGNOREMSG }, 86 { "1.3.2*", /* F-Secure */ 87 SSH_BUG_IGNOREMSG }, 88 { "Cisco-1.*", SSH_BUG_DHGEX_LARGE| 89 SSH_BUG_HOSTKEYS }, 90 { "*SSH Compatible Server*", /* Netscreen */ 91 SSH_BUG_PASSWORDPAD }, 92 { "*OSU_0*," 93 "OSU_1.0*," 94 "OSU_1.1*," 95 "OSU_1.2*," 96 "OSU_1.3*," 97 "OSU_1.4*," 98 "OSU_1.5alpha1*," 99 "OSU_1.5alpha2*," 100 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 101 { "*SSH_Version_Mapper*", 102 SSH_BUG_SCANNER }, 103 { "PuTTY_Local:*," /* dev versions < Sep 2014 */ 104 "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */ 105 "PuTTY_Release_0.5*," /* 0.58-0.59 */ 106 "PuTTY_Release_0.60*," 107 "PuTTY_Release_0.61*," 108 "PuTTY_Release_0.62*," 109 "PuTTY_Release_0.63*," 110 "PuTTY_Release_0.64*", 111 SSH_OLD_DHGEX }, 112 { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */ 113 { "Probe-*", 114 SSH_BUG_PROBE }, 115 { "TeraTerm SSH*," 116 "TTSSH/1.5.*," 117 "TTSSH/2.1*," 118 "TTSSH/2.2*," 119 "TTSSH/2.3*," 120 "TTSSH/2.4*," 121 "TTSSH/2.5*," 122 "TTSSH/2.6*," 123 "TTSSH/2.70*," 124 "TTSSH/2.71*," 125 "TTSSH/2.72*", SSH_BUG_HOSTKEYS }, 126 { "WinSCP_release_4*," 127 "WinSCP_release_5.0*," 128 "WinSCP_release_5.1," 129 "WinSCP_release_5.1.*," 130 "WinSCP_release_5.5," 131 "WinSCP_release_5.5.*," 132 "WinSCP_release_5.6," 133 "WinSCP_release_5.6.*," 134 "WinSCP_release_5.7," 135 "WinSCP_release_5.7.1," 136 "WinSCP_release_5.7.2," 137 "WinSCP_release_5.7.3," 138 "WinSCP_release_5.7.4", 139 SSH_OLD_DHGEX }, 140 { "ConfD-*", 141 SSH_BUG_UTF8TTYMODE }, 142 { "Twisted_*", 0 }, 143 { "Twisted*", SSH_BUG_DEBUG }, 144 { NULL, 0 } 145 }; 146 147 /* process table, return first match */ 148 for (i = 0; check[i].pat; i++) { 149 if (match_pattern_list(version, check[i].pat, 0) == 1) { 150 debug("match: %s pat %s compat 0x%08x", 151 version, check[i].pat, check[i].bugs); 152 datafellows = check[i].bugs; /* XXX for now */ 153 return check[i].bugs; 154 } 155 } 156 debug("no match: %s", version); 157 return 0; 158 } 159 160 #define SEP "," 161 int 162 proto_spec(const char *spec) 163 { 164 char *s, *p, *q; 165 int ret = SSH_PROTO_UNKNOWN; 166 167 if (spec == NULL) 168 return ret; 169 q = s = strdup(spec); 170 if (s == NULL) 171 return ret; 172 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 173 switch (atoi(p)) { 174 case 2: 175 ret |= SSH_PROTO_2; 176 break; 177 default: 178 logit("ignoring bad proto spec: '%s'.", p); 179 break; 180 } 181 } 182 free(s); 183 return ret; 184 } 185 186 char * 187 compat_cipher_proposal(char *cipher_prop) 188 { 189 if (!(datafellows & SSH_BUG_BIGENDIANAES)) 190 return cipher_prop; 191 debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 192 if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL) 193 fatal("match_filter_blacklist failed"); 194 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 195 if (*cipher_prop == '\0') 196 fatal("No supported ciphers found"); 197 return cipher_prop; 198 } 199 200 char * 201 compat_pkalg_proposal(char *pkalg_prop) 202 { 203 if (!(datafellows & SSH_BUG_RSASIGMD5)) 204 return pkalg_prop; 205 debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 206 if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL) 207 fatal("match_filter_blacklist failed"); 208 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 209 if (*pkalg_prop == '\0') 210 fatal("No supported PK algorithms found"); 211 return pkalg_prop; 212 } 213 214 char * 215 compat_kex_proposal(char *p) 216 { 217 if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) 218 return p; 219 debug2("%s: original KEX proposal: %s", __func__, p); 220 if ((datafellows & SSH_BUG_CURVE25519PAD) != 0) 221 if ((p = match_filter_blacklist(p, 222 "curve25519-sha256@libssh.org")) == NULL) 223 fatal("match_filter_blacklist failed"); 224 if ((datafellows & SSH_OLD_DHGEX) != 0) { 225 if ((p = match_filter_blacklist(p, 226 "diffie-hellman-group-exchange-sha256," 227 "diffie-hellman-group-exchange-sha1")) == NULL) 228 fatal("match_filter_blacklist failed"); 229 } 230 debug2("%s: compat KEX proposal: %s", __func__, p); 231 if (*p == '\0') 232 fatal("No supported key exchange algorithms found"); 233 return p; 234 } 235 236