1 /* $NetBSD: compat.c,v 1.20 2019/01/27 02:08:33 pgoyette Exp $ */ 2 /* $OpenBSD: compat.c,v 1.113 2018/08/13 02:41:05 djm Exp $ */ 3 4 /* 5 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 18 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 19 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 20 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 21 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 22 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 23 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 24 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 25 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28 #include "includes.h" 29 __RCSID("$NetBSD: compat.c,v 1.20 2019/01/27 02:08:33 pgoyette Exp $"); 30 #include <sys/types.h> 31 32 #include <stdlib.h> 33 #include <string.h> 34 #include <stdarg.h> 35 36 #include "xmalloc.h" 37 #include "packet.h" 38 #include "compat.h" 39 #include "log.h" 40 #include "match.h" 41 #include "kex.h" 42 43 int datafellows = 0; 44 45 /* datafellows bug compatibility */ 46 u_int 47 compat_datafellows(const char *version) 48 { 49 int i; 50 static struct { 51 const char *pat; 52 int bugs; 53 } check[] = { 54 { "OpenSSH_2.*," 55 "OpenSSH_3.0*," 56 "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR| 57 SSH_BUG_SIGTYPE}, 58 { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR|SSH_BUG_SIGTYPE }, 59 { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 60 SSH_BUG_SIGTYPE}, 61 { "OpenSSH_2*," 62 "OpenSSH_3*," 63 "OpenSSH_4*", SSH_BUG_SIGTYPE }, 64 { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT| 65 SSH_BUG_SIGTYPE}, 66 { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, 67 { "OpenSSH_6.5*," 68 "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD| 69 SSH_BUG_SIGTYPE}, 70 { "OpenSSH_7.0*," 71 "OpenSSH_7.1*," 72 "OpenSSH_7.2*," 73 "OpenSSH_7.3*," 74 "OpenSSH_7.4*," 75 "OpenSSH_7.5*," 76 "OpenSSH_7.6*," 77 "OpenSSH_7.7*", SSH_NEW_OPENSSH|SSH_BUG_SIGTYPE}, 78 { "OpenSSH*", SSH_NEW_OPENSSH }, 79 { "*MindTerm*", 0 }, 80 { "3.0.*", SSH_BUG_DEBUG }, 81 { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 82 { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 83 { "1.2.18*," 84 "1.2.19*," 85 "1.2.20*," 86 "1.2.21*," 87 "1.2.22*", SSH_BUG_IGNOREMSG }, 88 { "1.3.2*", /* F-Secure */ 89 SSH_BUG_IGNOREMSG }, 90 { "Cisco-1.*", SSH_BUG_DHGEX_LARGE| 91 SSH_BUG_HOSTKEYS }, 92 { "*SSH Compatible Server*", /* Netscreen */ 93 SSH_BUG_PASSWORDPAD }, 94 { "*OSU_0*," 95 "OSU_1.0*," 96 "OSU_1.1*," 97 "OSU_1.2*," 98 "OSU_1.3*," 99 "OSU_1.4*," 100 "OSU_1.5alpha1*," 101 "OSU_1.5alpha2*," 102 "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 103 { "*SSH_Version_Mapper*", 104 SSH_BUG_SCANNER }, 105 { "PuTTY_Local:*," /* dev versions < Sep 2014 */ 106 "PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */ 107 "PuTTY_Release_0.5*," /* 0.58-0.59 */ 108 "PuTTY_Release_0.60*," 109 "PuTTY_Release_0.61*," 110 "PuTTY_Release_0.62*," 111 "PuTTY_Release_0.63*," 112 "PuTTY_Release_0.64*", 113 SSH_OLD_DHGEX }, 114 { "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */ 115 { "Probe-*", 116 SSH_BUG_PROBE }, 117 { "TeraTerm SSH*," 118 "TTSSH/1.5.*," 119 "TTSSH/2.1*," 120 "TTSSH/2.2*," 121 "TTSSH/2.3*," 122 "TTSSH/2.4*," 123 "TTSSH/2.5*," 124 "TTSSH/2.6*," 125 "TTSSH/2.70*," 126 "TTSSH/2.71*," 127 "TTSSH/2.72*", SSH_BUG_HOSTKEYS }, 128 { "WinSCP_release_4*," 129 "WinSCP_release_5.0*," 130 "WinSCP_release_5.1," 131 "WinSCP_release_5.1.*," 132 "WinSCP_release_5.5," 133 "WinSCP_release_5.5.*," 134 "WinSCP_release_5.6," 135 "WinSCP_release_5.6.*," 136 "WinSCP_release_5.7," 137 "WinSCP_release_5.7.1," 138 "WinSCP_release_5.7.2," 139 "WinSCP_release_5.7.3," 140 "WinSCP_release_5.7.4", 141 SSH_OLD_DHGEX }, 142 { "ConfD-*", 143 SSH_BUG_UTF8TTYMODE }, 144 { "Twisted_*", 0 }, 145 { "Twisted*", SSH_BUG_DEBUG }, 146 { NULL, 0 } 147 }; 148 149 /* process table, return first match */ 150 for (i = 0; check[i].pat; i++) { 151 if (match_pattern_list(version, check[i].pat, 0) == 1) { 152 debug("match: %s pat %s compat 0x%08x", 153 version, check[i].pat, check[i].bugs); 154 datafellows = check[i].bugs; /* XXX for now */ 155 /* Check to see if the remote side is OpenSSH and not HPN */ 156 if(strstr(version,"OpenSSH") != NULL) 157 { 158 if (strstr(version,"hpn") == NULL) 159 { 160 datafellows |= SSH_BUG_LARGEWINDOW; 161 debug("Remote is NON-HPN aware"); 162 } 163 } 164 return check[i].bugs; 165 } 166 } 167 debug("no match: %s", version); 168 return 0; 169 } 170 171 #define SEP "," 172 int 173 proto_spec(const char *spec) 174 { 175 char *s, *p, *q; 176 int ret = SSH_PROTO_UNKNOWN; 177 178 if (spec == NULL) 179 return ret; 180 q = s = strdup(spec); 181 if (s == NULL) 182 return ret; 183 for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 184 switch (atoi(p)) { 185 case 2: 186 ret |= SSH_PROTO_2; 187 break; 188 default: 189 logit("ignoring bad proto spec: '%s'.", p); 190 break; 191 } 192 } 193 free(s); 194 return ret; 195 } 196 197 const char * 198 compat_cipher_proposal(const char *cipher_prop) 199 { 200 if (!(datafellows & SSH_BUG_BIGENDIANAES)) 201 return cipher_prop; 202 debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 203 if ((cipher_prop = match_filter_blacklist(cipher_prop, "aes*")) == NULL) 204 fatal("match_filter_blacklist failed"); 205 debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 206 if (*cipher_prop == '\0') 207 fatal("No supported ciphers found"); 208 return cipher_prop; 209 } 210 211 char * 212 compat_pkalg_proposal(char *pkalg_prop) 213 { 214 if (!(datafellows & SSH_BUG_RSASIGMD5)) 215 return pkalg_prop; 216 debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 217 if ((pkalg_prop = match_filter_blacklist(pkalg_prop, "ssh-rsa")) == NULL) 218 fatal("match_filter_blacklist failed"); 219 debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 220 if (*pkalg_prop == '\0') 221 fatal("No supported PK algorithms found"); 222 return pkalg_prop; 223 } 224 225 const char * 226 compat_kex_proposal(const char *p) 227 { 228 if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0) 229 return p; 230 debug2("%s: original KEX proposal: %s", __func__, p); 231 if ((datafellows & SSH_BUG_CURVE25519PAD) != 0) 232 if ((p = match_filter_blacklist(p, 233 "curve25519-sha256@libssh.org")) == NULL) 234 fatal("match_filter_blacklist failed"); 235 if ((datafellows & SSH_OLD_DHGEX) != 0) { 236 if ((p = match_filter_blacklist(p, 237 "diffie-hellman-group-exchange-sha256," 238 "diffie-hellman-group-exchange-sha1")) == NULL) 239 fatal("match_filter_blacklist failed"); 240 } 241 debug2("%s: compat KEX proposal: %s", __func__, p); 242 if (*p == '\0') 243 fatal("No supported key exchange algorithms found"); 244 return p; 245 } 246 247