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