compat.c revision 294328
1169689Skan/* $OpenBSD: compat.c,v 1.85 2014/04/20 02:49:32 djm Exp $ */ 2169689Skan/* 3169689Skan * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved. 4169689Skan * 5169689Skan * Redistribution and use in source and binary forms, with or without 6169689Skan * modification, are permitted provided that the following conditions 7169689Skan * are met: 8169689Skan * 1. Redistributions of source code must retain the above copyright 9169689Skan * notice, this list of conditions and the following disclaimer. 10169689Skan * 2. Redistributions in binary form must reproduce the above copyright 11169689Skan * notice, this list of conditions and the following disclaimer in the 12169689Skan * documentation and/or other materials provided with the distribution. 13169689Skan * 14169689Skan * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15169689Skan * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16169689Skan * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17169689Skan * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18169689Skan * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19169689Skan * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20169689Skan * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21169689Skan * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22169689Skan * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23169689Skan * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24169689Skan */ 25169689Skan 26169689Skan#include "includes.h" 27169689Skan__RCSID("$FreeBSD: head/crypto/openssh/compat.c 294328 2016-01-19 16:18:26Z des $"); 28169689Skan 29169689Skan#include <sys/types.h> 30169689Skan 31169689Skan#include <stdlib.h> 32169689Skan#include <string.h> 33169689Skan#include <stdarg.h> 34169689Skan 35169689Skan#include "xmalloc.h" 36169689Skan#include "buffer.h" 37169689Skan#include "packet.h" 38169689Skan#include "compat.h" 39169689Skan#include "log.h" 40169689Skan#include "match.h" 41169689Skan 42169689Skanint compat13 = 0; 43169689Skanint compat20 = 0; 44169689Skanint datafellows = 0; 45169689Skan 46169689Skanvoid 47169689Skanenable_compat20(void) 48169689Skan{ 49169689Skan if (compat20) 50169689Skan return; 51169689Skan debug("Enabling compatibility mode for protocol 2.0"); 52169689Skan compat20 = 1; 53169689Skan} 54169689Skanvoid 55169689Skanenable_compat13(void) 56169689Skan{ 57169689Skan debug("Enabling compatibility mode for protocol 1.3"); 58169689Skan compat13 = 1; 59169689Skan} 60169689Skan/* datafellows bug compatibility */ 61169689Skanvoid 62169689Skancompat_datafellows(const char *version) 63169689Skan{ 64169689Skan int i; 65169689Skan static struct { 66169689Skan char *pat; 67169689Skan int bugs; 68169689Skan } check[] = { 69169689Skan { "OpenSSH-2.0*," 70169689Skan "OpenSSH-2.1*," 71169689Skan "OpenSSH_2.1*," 72169689Skan "OpenSSH_2.2*", SSH_OLD_SESSIONID|SSH_BUG_BANNER| 73169689Skan SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 74169689Skan SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 75169689Skan { "OpenSSH_2.3.0*", SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES| 76169689Skan SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 77169689Skan SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 78169689Skan { "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| 79169689Skan SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 80169689Skan SSH_OLD_FORWARD_ADDR}, 81169689Skan { "OpenSSH_2.5.0p1*," 82169689Skan "OpenSSH_2.5.1p1*", 83169689Skan SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX| 84169689Skan SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 85169689Skan SSH_OLD_FORWARD_ADDR}, 86169689Skan { "OpenSSH_2.5.0*," 87169689Skan "OpenSSH_2.5.1*," 88169689Skan "OpenSSH_2.5.2*", SSH_OLD_DHGEX|SSH_BUG_NOREKEY| 89169689Skan SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 90169689Skan { "OpenSSH_2.5.3*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF| 91169689Skan SSH_OLD_FORWARD_ADDR}, 92169689Skan { "OpenSSH_2.*," 93169689Skan "OpenSSH_3.0*," 94169689Skan "OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR}, 95169689Skan { "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR }, 96169689Skan { "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF}, 97169689Skan { "OpenSSH_4*", 0 }, 98169689Skan { "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT}, 99169689Skan { "OpenSSH_6.6.1*", SSH_NEW_OPENSSH}, 100169689Skan { "OpenSSH_6.5*," 101169689Skan "OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD}, 102169689Skan { "OpenSSH*", SSH_NEW_OPENSSH }, 103169689Skan { "*MindTerm*", 0 }, 104169689Skan { "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 105169689Skan SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 106169689Skan SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| 107169689Skan SSH_BUG_FIRSTKEX }, 108169689Skan { "2.1 *", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 109169689Skan SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 110169689Skan SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE| 111169689Skan SSH_BUG_FIRSTKEX }, 112169689Skan { "2.0.13*," 113169689Skan "2.0.14*," 114169689Skan "2.0.15*," 115169689Skan "2.0.16*," 116169689Skan "2.0.17*," 117169689Skan "2.0.18*," 118169689Skan "2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 119169689Skan SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 120169689Skan SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 121169689Skan SSH_BUG_PKOK|SSH_BUG_RSASIGMD5| 122169689Skan SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE| 123169689Skan SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 124169689Skan { "2.0.11*," 125169689Skan "2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 126169689Skan SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 127169689Skan SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 128169689Skan SSH_BUG_PKAUTH|SSH_BUG_PKOK| 129169689Skan SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 130169689Skan SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX }, 131169689Skan { "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC| 132169689Skan SSH_OLD_SESSIONID|SSH_BUG_DEBUG| 133169689Skan SSH_BUG_PKSERVICE|SSH_BUG_X11FWD| 134169689Skan SSH_BUG_PKAUTH|SSH_BUG_PKOK| 135169689Skan SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE| 136169689Skan SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN| 137169689Skan SSH_BUG_FIRSTKEX }, 138169689Skan { "2.2.0*," 139169689Skan "2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG| 140169689Skan SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX }, 141169689Skan { "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5| 142169689Skan SSH_BUG_FIRSTKEX }, 143169689Skan { "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */ 144169689Skan { "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX| 145169689Skan SSH_BUG_RFWD_ADDR }, 146169689Skan { "3.0.*", SSH_BUG_DEBUG }, 147169689Skan { "3.0 SecureCRT*", SSH_OLD_SESSIONID }, 148169689Skan { "1.7 SecureFX*", SSH_OLD_SESSIONID }, 149169689Skan { "1.2.18*," 150169689Skan "1.2.19*," 151169689Skan "1.2.20*," 152169689Skan "1.2.21*," 153169689Skan "1.2.22*", SSH_BUG_IGNOREMSG }, 154169689Skan { "1.3.2*", /* F-Secure */ 155169689Skan SSH_BUG_IGNOREMSG }, 156169689Skan { "*SSH Compatible Server*", /* Netscreen */ 157169689Skan SSH_BUG_PASSWORDPAD }, 158169689Skan { "*OSU_0*," 159169689Skan "OSU_1.0*," 160169689Skan "OSU_1.1*," 161169689Skan "OSU_1.2*," 162169689Skan "OSU_1.3*," 163169689Skan "OSU_1.4*," 164169689Skan "OSU_1.5alpha1*," 165169689Skan "OSU_1.5alpha2*," 166169689Skan "OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD }, 167169689Skan { "*SSH_Version_Mapper*", 168169689Skan SSH_BUG_SCANNER }, 169169689Skan { "Probe-*", 170169689Skan SSH_BUG_PROBE }, 171169689Skan { NULL, 0 } 172169689Skan }; 173169689Skan 174169689Skan /* process table, return first match */ 175169689Skan for (i = 0; check[i].pat; i++) { 176169689Skan if (match_pattern_list(version, check[i].pat, 177169689Skan strlen(check[i].pat), 0) == 1) { 178169689Skan datafellows = check[i].bugs; 179169689Skan debug("match: %s pat %s compat 0x%08x", 180169689Skan version, check[i].pat, datafellows); 181169689Skan return; 182169689Skan } 183169689Skan } 184169689Skan debug("no match: %s", version); 185169689Skan} 186169689Skan 187169689Skan#define SEP "," 188169689Skanint 189169689Skanproto_spec(const char *spec) 190169689Skan{ 191169689Skan char *s, *p, *q; 192169689Skan int ret = SSH_PROTO_UNKNOWN; 193169689Skan 194169689Skan if (spec == NULL) 195169689Skan return ret; 196169689Skan q = s = xstrdup(spec); 197169689Skan for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) { 198169689Skan switch (atoi(p)) { 199169689Skan case 1: 200169689Skan if (ret == SSH_PROTO_UNKNOWN) 201169689Skan ret |= SSH_PROTO_1_PREFERRED; 202169689Skan ret |= SSH_PROTO_1; 203169689Skan break; 204169689Skan case 2: 205169689Skan ret |= SSH_PROTO_2; 206169689Skan break; 207169689Skan default: 208169689Skan logit("ignoring bad proto spec: '%s'.", p); 209169689Skan break; 210169689Skan } 211169689Skan } 212169689Skan free(s); 213169689Skan return ret; 214169689Skan} 215169689Skan 216169689Skan/* 217169689Skan * Filters a proposal string, excluding any algorithm matching the 'filter' 218169689Skan * pattern list. 219169689Skan */ 220169689Skanstatic char * 221169689Skanfilter_proposal(char *proposal, const char *filter) 222169689Skan{ 223169689Skan Buffer b; 224169689Skan char *orig_prop, *fix_prop; 225169689Skan char *cp, *tmp; 226169689Skan 227169689Skan buffer_init(&b); 228169689Skan tmp = orig_prop = xstrdup(proposal); 229169689Skan while ((cp = strsep(&tmp, ",")) != NULL) { 230169689Skan if (match_pattern_list(cp, filter, strlen(cp), 0) != 1) { 231169689Skan if (buffer_len(&b) > 0) 232169689Skan buffer_append(&b, ",", 1); 233169689Skan buffer_append(&b, cp, strlen(cp)); 234169689Skan } else 235169689Skan debug2("Compat: skipping algorithm \"%s\"", cp); 236169689Skan } 237169689Skan buffer_append(&b, "\0", 1); 238169689Skan fix_prop = xstrdup(buffer_ptr(&b)); 239169689Skan buffer_free(&b); 240169689Skan free(orig_prop); 241169689Skan 242169689Skan return fix_prop; 243169689Skan} 244169689Skan 245169689Skanchar * 246169689Skancompat_cipher_proposal(char *cipher_prop) 247169689Skan{ 248169689Skan if (!(datafellows & SSH_BUG_BIGENDIANAES)) 249169689Skan return cipher_prop; 250169689Skan debug2("%s: original cipher proposal: %s", __func__, cipher_prop); 251169689Skan cipher_prop = filter_proposal(cipher_prop, "aes*"); 252169689Skan debug2("%s: compat cipher proposal: %s", __func__, cipher_prop); 253169689Skan if (*cipher_prop == '\0') 254169689Skan fatal("No supported ciphers found"); 255169689Skan return cipher_prop; 256169689Skan} 257169689Skan 258169689Skanchar * 259169689Skancompat_pkalg_proposal(char *pkalg_prop) 260169689Skan{ 261169689Skan if (!(datafellows & SSH_BUG_RSASIGMD5)) 262169689Skan return pkalg_prop; 263169689Skan debug2("%s: original public key proposal: %s", __func__, pkalg_prop); 264169689Skan pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa"); 265169689Skan debug2("%s: compat public key proposal: %s", __func__, pkalg_prop); 266169689Skan if (*pkalg_prop == '\0') 267169689Skan fatal("No supported PK algorithms found"); 268169689Skan return pkalg_prop; 269169689Skan} 270169689Skan 271169689Skanchar * 272169689Skancompat_kex_proposal(char *kex_prop) 273169689Skan{ 274169689Skan if (!(datafellows & SSH_BUG_CURVE25519PAD)) 275169689Skan return kex_prop; 276169689Skan debug2("%s: original KEX proposal: %s", __func__, kex_prop); 277169689Skan kex_prop = filter_proposal(kex_prop, "curve25519-sha256@libssh.org"); 278169689Skan debug2("%s: compat KEX proposal: %s", __func__, kex_prop); 279169689Skan if (*kex_prop == '\0') 280169689Skan fatal("No supported key exchange algorithms found"); 281169689Skan return kex_prop; 282169689Skan} 283169689Skan 284169689Skan