326 lines
9.1 KiB
C
326 lines
9.1 KiB
C
/* $OpenBSD: compat.c,v 1.99 2016/05/24 02:31:57 dtucker Exp $ */
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/*
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* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <stdlib.h>
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#include <string.h>
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#include <stdarg.h>
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#include "xmalloc.h"
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#include "buffer.h"
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#include "packet.h"
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#include "compat.h"
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#include "log.h"
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#include "match.h"
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int compat13 = 0;
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int compat20 = 0;
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int datafellows = 0;
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void
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enable_compat20(void)
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{
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if (compat20)
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return;
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debug("Enabling compatibility mode for protocol 2.0");
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compat20 = 1;
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}
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void
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enable_compat13(void)
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{
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debug("Enabling compatibility mode for protocol 1.3");
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compat13 = 1;
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}
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/* datafellows bug compatibility */
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u_int
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compat_datafellows(const char *version)
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{
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int i;
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static struct {
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char *pat;
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int bugs;
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} check[] = {
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{ "OpenSSH-2.0*,"
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"OpenSSH-2.1*,"
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"OpenSSH_2.1*,"
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"OpenSSH_2.2*", SSH_OLD_SESSIONID|SSH_BUG_BANNER|
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SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
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SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.3.0*", SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
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SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
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SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
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SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
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SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.5.0p1*,"
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"OpenSSH_2.5.1p1*",
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SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
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SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
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SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.5.0*,"
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"OpenSSH_2.5.1*,"
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"OpenSSH_2.5.2*", SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
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SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.5.3*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
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SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_2.*,"
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"OpenSSH_3.0*,"
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"OpenSSH_3.1*", SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
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{ "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR },
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{ "Sun_SSH_1.0*", SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
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{ "OpenSSH_4*", 0 },
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{ "OpenSSH_5*", SSH_NEW_OPENSSH|SSH_BUG_DYNAMIC_RPORT},
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{ "OpenSSH_6.6.1*", SSH_NEW_OPENSSH},
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{ "OpenSSH_6.5*,"
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"OpenSSH_6.6*", SSH_NEW_OPENSSH|SSH_BUG_CURVE25519PAD},
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{ "OpenSSH*", SSH_NEW_OPENSSH },
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{ "*MindTerm*", 0 },
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{ "2.1.0*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
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SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
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SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
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SSH_BUG_FIRSTKEX },
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{ "2.1 *", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
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SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
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SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
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SSH_BUG_FIRSTKEX },
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{ "2.0.13*,"
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"2.0.14*,"
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"2.0.15*,"
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"2.0.16*,"
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"2.0.17*,"
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"2.0.18*,"
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"2.0.19*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
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SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
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SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
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SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
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SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
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SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
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{ "2.0.11*,"
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"2.0.12*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
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SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
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SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
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SSH_BUG_PKAUTH|SSH_BUG_PKOK|
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SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
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SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
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{ "2.0.*", SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
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SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
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SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
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SSH_BUG_PKAUTH|SSH_BUG_PKOK|
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SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
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SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
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SSH_BUG_FIRSTKEX },
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{ "2.2.0*,"
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"2.3.0*", SSH_BUG_HMAC|SSH_BUG_DEBUG|
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SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
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{ "2.3.*", SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
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SSH_BUG_FIRSTKEX },
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{ "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */
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{ "2.*", SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
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SSH_BUG_RFWD_ADDR },
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{ "3.0.*", SSH_BUG_DEBUG },
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{ "3.0 SecureCRT*", SSH_OLD_SESSIONID },
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{ "1.7 SecureFX*", SSH_OLD_SESSIONID },
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{ "1.2.18*,"
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"1.2.19*,"
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"1.2.20*,"
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"1.2.21*,"
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"1.2.22*", SSH_BUG_IGNOREMSG },
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{ "1.3.2*", /* F-Secure */
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SSH_BUG_IGNOREMSG },
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{ "Cisco-1.*", SSH_BUG_DHGEX_LARGE|
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SSH_BUG_HOSTKEYS },
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{ "*SSH Compatible Server*", /* Netscreen */
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SSH_BUG_PASSWORDPAD },
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{ "*OSU_0*,"
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"OSU_1.0*,"
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"OSU_1.1*,"
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"OSU_1.2*,"
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"OSU_1.3*,"
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"OSU_1.4*,"
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"OSU_1.5alpha1*,"
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"OSU_1.5alpha2*,"
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"OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
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{ "*SSH_Version_Mapper*",
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SSH_BUG_SCANNER },
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{ "PuTTY_Local:*," /* dev versions < Sep 2014 */
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"PuTTY-Release-0.5*," /* 0.50-0.57, DH-GEX in >=0.52 */
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"PuTTY_Release_0.5*," /* 0.58-0.59 */
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"PuTTY_Release_0.60*,"
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"PuTTY_Release_0.61*,"
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"PuTTY_Release_0.62*,"
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"PuTTY_Release_0.63*,"
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"PuTTY_Release_0.64*",
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SSH_OLD_DHGEX },
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{ "FuTTY*", SSH_OLD_DHGEX }, /* Putty Fork */
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{ "Probe-*",
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SSH_BUG_PROBE },
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{ "TeraTerm SSH*,"
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"TTSSH/1.5.*,"
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"TTSSH/2.1*,"
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"TTSSH/2.2*,"
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"TTSSH/2.3*,"
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"TTSSH/2.4*,"
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"TTSSH/2.5*,"
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"TTSSH/2.6*,"
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"TTSSH/2.70*,"
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"TTSSH/2.71*,"
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"TTSSH/2.72*", SSH_BUG_HOSTKEYS },
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{ "WinSCP_release_4*,"
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"WinSCP_release_5.0*,"
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"WinSCP_release_5.1*,"
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"WinSCP_release_5.5*,"
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"WinSCP_release_5.6*,"
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"WinSCP_release_5.7,"
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"WinSCP_release_5.7.1,"
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"WinSCP_release_5.7.2,"
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"WinSCP_release_5.7.3,"
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"WinSCP_release_5.7.4",
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SSH_OLD_DHGEX },
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{ NULL, 0 }
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};
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/* process table, return first match */
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for (i = 0; check[i].pat; i++) {
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if (match_pattern_list(version, check[i].pat, 0) == 1) {
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debug("match: %s pat %s compat 0x%08x",
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version, check[i].pat, check[i].bugs);
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datafellows = check[i].bugs; /* XXX for now */
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return check[i].bugs;
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}
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}
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debug("no match: %s", version);
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return 0;
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}
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#define SEP ","
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int
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proto_spec(const char *spec)
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{
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char *s, *p, *q;
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int ret = SSH_PROTO_UNKNOWN;
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if (spec == NULL)
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return ret;
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q = s = strdup(spec);
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if (s == NULL)
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return ret;
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for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
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switch (atoi(p)) {
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case 1:
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#ifdef WITH_SSH1
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if (ret == SSH_PROTO_UNKNOWN)
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ret |= SSH_PROTO_1_PREFERRED;
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ret |= SSH_PROTO_1;
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#endif
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break;
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case 2:
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ret |= SSH_PROTO_2;
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break;
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default:
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logit("ignoring bad proto spec: '%s'.", p);
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break;
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}
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}
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free(s);
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return ret;
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}
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/*
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* Filters a proposal string, excluding any algorithm matching the 'filter'
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* pattern list.
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*/
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static char *
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filter_proposal(char *proposal, const char *filter)
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{
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Buffer b;
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char *orig_prop, *fix_prop;
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char *cp, *tmp;
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buffer_init(&b);
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tmp = orig_prop = xstrdup(proposal);
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while ((cp = strsep(&tmp, ",")) != NULL) {
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if (match_pattern_list(cp, filter, 0) != 1) {
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if (buffer_len(&b) > 0)
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buffer_append(&b, ",", 1);
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buffer_append(&b, cp, strlen(cp));
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} else
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debug2("Compat: skipping algorithm \"%s\"", cp);
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}
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buffer_append(&b, "\0", 1);
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fix_prop = xstrdup((char *)buffer_ptr(&b));
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buffer_free(&b);
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free(orig_prop);
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return fix_prop;
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}
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char *
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compat_cipher_proposal(char *cipher_prop)
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{
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if (!(datafellows & SSH_BUG_BIGENDIANAES))
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return cipher_prop;
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debug2("%s: original cipher proposal: %s", __func__, cipher_prop);
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cipher_prop = filter_proposal(cipher_prop, "aes*");
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debug2("%s: compat cipher proposal: %s", __func__, cipher_prop);
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if (*cipher_prop == '\0')
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fatal("No supported ciphers found");
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return cipher_prop;
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}
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char *
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compat_pkalg_proposal(char *pkalg_prop)
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{
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if (!(datafellows & SSH_BUG_RSASIGMD5))
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return pkalg_prop;
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debug2("%s: original public key proposal: %s", __func__, pkalg_prop);
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pkalg_prop = filter_proposal(pkalg_prop, "ssh-rsa");
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debug2("%s: compat public key proposal: %s", __func__, pkalg_prop);
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if (*pkalg_prop == '\0')
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fatal("No supported PK algorithms found");
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return pkalg_prop;
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}
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char *
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compat_kex_proposal(char *p)
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{
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if ((datafellows & (SSH_BUG_CURVE25519PAD|SSH_OLD_DHGEX)) == 0)
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return p;
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debug2("%s: original KEX proposal: %s", __func__, p);
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if ((datafellows & SSH_BUG_CURVE25519PAD) != 0)
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p = filter_proposal(p, "curve25519-sha256@libssh.org");
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if ((datafellows & SSH_OLD_DHGEX) != 0) {
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p = filter_proposal(p, "diffie-hellman-group-exchange-sha256");
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p = filter_proposal(p, "diffie-hellman-group-exchange-sha1");
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}
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debug2("%s: compat KEX proposal: %s", __func__, p);
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if (*p == '\0')
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fatal("No supported key exchange algorithms found");
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return p;
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}
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