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			326 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			326 lines
		
	
	
		
			9.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /* $OpenBSD: compat.c,v 1.97 2015/08/19 23:21:42 djm 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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| 
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| #include "includes.h"
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| 
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| #include <sys/types.h>
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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| 
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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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| /*
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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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| 
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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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| 
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| 	return fix_prop;
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| }
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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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| 
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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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| 
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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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| 
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