1 /* $OpenBSD: compat.c,v 1.106 2018/02/16 04:43:11 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 "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 #include "kex.h" 41 42 int datafellows = 0; 43 44 /* datafellows bug compatibility */ 45 u_int 46 compat_datafellows(const char *version) 47 { 48 int i; 49 static struct { 50 char *pat; 51 int bugs; 52 } check[] = { 53 { "OpenSSH_2.*," 54 "OpenSSH_3.0*," 55 "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 56 { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR }, 57 { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF}, 58 { "OpenSSH_2*," 59 "OpenSSH_3*," 60 "OpenSSH_4*", 0 }, 61 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, 62 { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH}, 63 { "OpenSSH_6.5*," 64 "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD}, 65 { "OpenSSH*", SSH_NEW_OPENSSH }, 66 { "*MindTerm*", 0 }, 67 { "3.0.*", SSH_BUG_DEBUG }, 68 { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 69 { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 70 { "1.2.18*," 71 "1.2.19*," 72 "1.2.20*," 73 "1.2.21*," 74 "1.2.22*", SSH_BUG_IGNOREMSG }, 75 { "1.3.2*", /* F-Secure */ 76 SSH_BUG_IGNOREMSG }, 77 { "Cisco-1.*", SSH_BUG_DHGEX_LARGE| 78 SSH_BUG_HOSTKEYS }, 79 { "*SSH Compatible Server*", /* Netscreen */ 80 SSH_BUG_PASSWORDPAD }, 81 { "*OSU_0*," 82 "OSU_1.0*," 83 "OSU_1.1*," 84 "OSU_1.2*," 85 "OSU_1.3*," 86 "OSU_1.4*," 87 "OSU_1.5alpha1*," 88 "OSU_1.5alpha2*," 89 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 90 { "*SSH_Version_Mapper*", 91 SSH_BUG_SCANNER }, 92 { "PuTTY_Local:*," /* dev versions < Sep 2014 */ 93 "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */ 94 "PuTTY_Release_0.5*," /* 0.58-0.59 */ 95 "PuTTY_Release_0.60*," 96 "PuTTY_Release_0.61*," 97 "PuTTY_Release_0.62*," 98 "PuTTY_Release_0.63*," 99 "PuTTY_Release_0.64*", 100 SSH_OLD_DHGEX }, 101 { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */ 102 { "Probe-*", 103 SSH_BUG_PROBE }, 104 { "TeraTerm SSH*," 105 "TTSSH/1.5.*," 106 "TTSSH/2.1*," 107 "TTSSH/2.2*," 108 "TTSSH/2.3*," 109 "TTSSH/2.4*," 110 "TTSSH/2.5*," 111 "TTSSH/2.6*," 112 "TTSSH/2.70*," 113 "TTSSH/2.71*," 114 "TTSSH/2.72*", SSH_BUG_HOSTKEYS }, 115 { "WinSCP_release_4*," 116 "WinSCP_release_5.0*," 117 "WinSCP_release_5.1," 118 "WinSCP_release_5.1.*," 119 "WinSCP_release_5.5," 120 "WinSCP_release_5.5.*," 121 "WinSCP_release_5.6," 122 "WinSCP_release_5.6.*," 123 "WinSCP_release_5.7," 124 "WinSCP_release_5.7.1," 125 "WinSCP_release_5.7.2," 126 "WinSCP_release_5.7.3," 127 "WinSCP_release_5.7.4", 128 SSH_OLD_DHGEX }, 129 { "ConfD-*", 130 SSH_BUG_UTF8TTYMODE }, 131 { NULL, 0 } 132 }; 133 134 /* process table, return first match */ 135 for (i = 0; check[i].pat; i++) { 136 if (match_pattern_list(version, check[i].pat, 0) == 1) { 137 debug("match: %s pat %s compat 0x%08x", 138 version, check[i].pat, check[i].bugs); 139 datafellows = check[i].bugs; /* XXX for now */ 140 return check[i].bugs; 141 } 142 } 143 debug("no match: %s", version); 144 return 0; 145 } 146 147 #define SEP "," 148 int 149 proto_spec(const char *spec) 150 { 151 char *s, *p, *q; 152 int ret = SSH_PROTO_UNKNOWN; 153 154 if (spec == NULL) 155 return ret; 156 q = s = strdup(spec); 157 if (s == NULL) 158 return ret; 159 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 160 switch (atoi(p)) { 161 case 2: 162 ret |= SSH_PROTO_2; 163 break; 164 default: 165 logit("ignoring bad proto spec: '%s'.", p); 166 break; 167 } 168 } 169 free(s); 170 return ret; 171 } 172 173 char * 174 compat_cipher_proposal(char *cipher_prop) 175 { 176 if (!(datafellows & SSH_BUG_BIGENDIANAES)) 177 return cipher_prop; 178 debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 179 if ((cipher_prop = match_filter_list(cipher_prop, "aes*")) == NULL) 180 fatal("match_filter_list failed"); 181 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 182 if (*cipher_prop == '\0') 183 fatal("No supported ciphers found"); 184 return cipher_prop; 185 } 186 187 char * 188 compat_pkalg_proposal(char *pkalg_prop) 189 { 190 if (!(datafellows & SSH_BUG_RSASIGMD5)) 191 return pkalg_prop; 192 debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 193 if ((pkalg_prop = match_filter_list(pkalg_prop, "ssh-rsa")) == NULL) 194 fatal("match_filter_list failed"); 195 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 196 if (*pkalg_prop == '\0') 197 fatal("No supported PK algorithms found"); 198 return pkalg_prop; 199 } 200 201 char * 202 compat_kex_proposal(char *p) 203 { 204 if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) 205 return p; 206 debug2("%s: original KEX proposal: %s", __func__, p); 207 if ((datafellows & SSH_BUG_CURVE25519PAD) != 0) 208 if ((p = match_filter_list(p, 209 "curve25519-sha256@libssh.org")) == NULL) 210 fatal("match_filter_list failed"); 211 if ((datafellows & SSH_OLD_DHGEX) != 0) { 212 if ((p = match_filter_list(p, 213 "diffie-hellman-group-exchange-sha256," 214 "diffie-hellman-group-exchange-sha1")) == NULL) 215 fatal("match_filter_list failed"); 216 } 217 debug2("%s: compat KEX proposal: %s", __func__, p); 218 if (*p == '\0') 219 fatal("No supported key exchange algorithms found"); 220 return p; 221 } 222 223