[gssapi-openssh.git] / openssh / compat.c

/* $OpenBSD: compat.c,v 1.77 2006/12/12 03:58:42 djm Exp $ */
/*
 * Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"

#include <sys/types.h>

#include <stdlib.h>
#include <string.h>
#include <stdarg.h>

#include "xmalloc.h"
#include "buffer.h"
#include "packet.h"
#include "compat.h"
#include "log.h"
#include "match.h"

int compat13 = 0;
int compat20 = 0;
int datafellows = 0;

void
enable_compat20(void)
{
	debug("Enabling compatibility mode for protocol 2.0");
	compat20 = 1;
}
void
enable_compat13(void)
{
	debug("Enabling compatibility mode for protocol 1.3");
	compat13 = 1;
}
/* datafellows bug compatibility */
void
compat_datafellows(const char *version)
{
	int i;
	static struct {
		char	*pat;
		int	bugs;
	} check[] = {
		{ "OpenSSH-2.0*,"
		  "OpenSSH-2.1*,"
		  "OpenSSH_2.1*,"
		  "OpenSSH_2.2*",	SSH_OLD_SESSIONID|SSH_BUG_BANNER|
					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.3.0*",	SSH_BUG_BANNER|SSH_BUG_BIGENDIANAES|
					SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.3.*",	SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
					SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.5.0p1*,"
		  "OpenSSH_2.5.1p1*",
					SSH_BUG_BIGENDIANAES|SSH_OLD_DHGEX|
					SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
					SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.5.0*,"
		  "OpenSSH_2.5.1*,"
		  "OpenSSH_2.5.2*",	SSH_OLD_DHGEX|SSH_BUG_NOREKEY|
					SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.5.3*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF|
					SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_2.*,"
		  "OpenSSH_3.0*,"
		  "OpenSSH_3.1*",	SSH_BUG_EXTEOF|SSH_OLD_FORWARD_ADDR},
		{ "OpenSSH_3.*",	SSH_OLD_FORWARD_ADDR },
		{ "Sun_SSH_1.0*",	SSH_BUG_NOREKEY|SSH_BUG_EXTEOF},
		{ "OpenSSH*",		0 },
		{ "*MindTerm*",		0 },
		{ "2.1.0*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
					SSH_BUG_FIRSTKEX },
		{ "2.1 *",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
					SSH_BUG_RSASIGMD5|SSH_BUG_HBSERVICE|
					SSH_BUG_FIRSTKEX },
		{ "2.0.13*,"
		  "2.0.14*,"
		  "2.0.15*,"
		  "2.0.16*,"
		  "2.0.17*,"
		  "2.0.18*,"
		  "2.0.19*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
					SSH_BUG_PKOK|SSH_BUG_RSASIGMD5|
					SSH_BUG_HBSERVICE|SSH_BUG_OPENFAILURE|
					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
		{ "2.0.11*,"
		  "2.0.12*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
					SSH_BUG_DUMMYCHAN|SSH_BUG_FIRSTKEX },
		{ "2.0.*",		SSH_BUG_SIGBLOB|SSH_BUG_HMAC|
					SSH_OLD_SESSIONID|SSH_BUG_DEBUG|
					SSH_BUG_PKSERVICE|SSH_BUG_X11FWD|
					SSH_BUG_PKAUTH|SSH_BUG_PKOK|
					SSH_BUG_RSASIGMD5|SSH_BUG_OPENFAILURE|
					SSH_BUG_DERIVEKEY|SSH_BUG_DUMMYCHAN|
					SSH_BUG_FIRSTKEX },
		{ "2.2.0*,"
		  "2.3.0*",		SSH_BUG_HMAC|SSH_BUG_DEBUG|
					SSH_BUG_RSASIGMD5|SSH_BUG_FIRSTKEX },
		{ "2.3.*",		SSH_BUG_DEBUG|SSH_BUG_RSASIGMD5|
					SSH_BUG_FIRSTKEX },
		{ "2.4",		SSH_OLD_SESSIONID },	/* Van Dyke */
		{ "2.*",		SSH_BUG_DEBUG|SSH_BUG_FIRSTKEX|
					SSH_BUG_RFWD_ADDR },
		{ "3.0.*",		SSH_BUG_DEBUG },
		{ "3.0 SecureCRT*",	SSH_OLD_SESSIONID },
		{ "1.7 SecureFX*",	SSH_OLD_SESSIONID },
		{ "1.2.18*,"
		  "1.2.19*,"
		  "1.2.20*,"
		  "1.2.21*,"
		  "1.2.22*",		SSH_BUG_IGNOREMSG },
		{ "1.3.2*",		/* F-Secure */
					SSH_BUG_IGNOREMSG },
		{ "*SSH Compatible Server*",			/* Netscreen */
					SSH_BUG_PASSWORDPAD },
		{ "*OSU_0*,"
		  "OSU_1.0*,"
		  "OSU_1.1*,"
		  "OSU_1.2*,"
		  "OSU_1.3*,"
		  "OSU_1.4*,"
		  "OSU_1.5alpha1*,"
		  "OSU_1.5alpha2*,"
		  "OSU_1.5alpha3*",	SSH_BUG_PASSWORDPAD },
		{ "*SSH_Version_Mapper*",
					SSH_BUG_SCANNER },
		{ "Probe-*",
					SSH_BUG_PROBE },
		{ NULL,			0 }
	};

	/* process table, return first match */
	for (i = 0; check[i].pat; i++) {
		if (match_pattern_list(version, check[i].pat,
		    strlen(check[i].pat), 0) == 1) {
			debug("match: %s pat %s", version, check[i].pat);
			datafellows = check[i].bugs;
			/* Check to see if the remote side is OpenSSH and not HPN */
			if(strstr(version,"OpenSSH") != NULL)
			{
				if (strstr(version,"hpn") == NULL)
				{
					datafellows |= SSH_BUG_LARGEWINDOW;
					debug("Remote is NON-HPN aware");
				}
			}
			return;
		}
	}
	debug("no match: %s", version);
}

#define	SEP	","
int
proto_spec(const char *spec)
{
	char *s, *p, *q;
	int ret = SSH_PROTO_UNKNOWN;

	if (spec == NULL)
		return ret;
	q = s = xstrdup(spec);
	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
		switch (atoi(p)) {
		case 1:
			if (ret == SSH_PROTO_UNKNOWN)
				ret |= SSH_PROTO_1_PREFERRED;
			ret |= SSH_PROTO_1;
			break;
		case 2:
			ret |= SSH_PROTO_2;
			break;
		default:
			logit("ignoring bad proto spec: '%s'.", p);
			break;
		}
	}
	xfree(s);
	return ret;
}

char *
compat_cipher_proposal(char *cipher_prop)
{
	Buffer b;
	char *orig_prop, *fix_ciphers;
	char *cp, *tmp;

	if (!(datafellows & SSH_BUG_BIGENDIANAES))
		return(cipher_prop);

	buffer_init(&b);
	tmp = orig_prop = xstrdup(cipher_prop);
	while ((cp = strsep(&tmp, ",")) != NULL) {
		if (strncmp(cp, "aes", 3) != 0) {
			if (buffer_len(&b) > 0)
				buffer_append(&b, ",", 1);
			buffer_append(&b, cp, strlen(cp));
		}
	}
	buffer_append(&b, "\0", 1);
	fix_ciphers = xstrdup(buffer_ptr(&b));
	buffer_free(&b);
	xfree(orig_prop);
	debug2("Original cipher proposal: %s", cipher_prop);
	debug2("Compat cipher proposal: %s", fix_ciphers);
	if (!*fix_ciphers)
		fatal("No available ciphers found.");

	return(fix_ciphers);
}
Commit	Line	Data
0b90ac93	1	/* $OpenBSD: compat.c,v 1.77 2006/12/12 03:58:42 djm Exp $ */
3c0ef626	2	/*
1e608e42	3	* Copyright (c) 1999, 2000, 2001, 2002 Markus Friedl. All rights reserved.
3c0ef626	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 "includes.h"
3c0ef626	27
30460aeb	28	#include <sys/types.h>
	29
	30	#include <stdlib.h>
	31	#include <string.h>
	32	#include <stdarg.h>
	33
	34	#include "xmalloc.h"
1e608e42	35	#include "buffer.h"
3c0ef626	36	#include "packet.h"
3c0ef626	37	#include "compat.h"
3c0ef626	38	#include "log.h"
1e608e42	39	#include "match.h"
3c0ef626	40
	41	int compat13 = 0;
	42	int compat20 = 0;
	43	int datafellows = 0;
	44
	45	void
	46	enable_compat20(void)
	47	{
d03f4262	48	debug("Enabling compatibility mode for protocol 2.0");
3c0ef626	49	compat20 = 1;
	50	}
	51	void
	52	enable_compat13(void)
	53	{
d03f4262	54	debug("Enabling compatibility mode for protocol 1.3");
3c0ef626	55	compat13 = 1;
	56	}
	57	/* datafellows bug compatibility */
	58	void
	59	compat_datafellows(const char *version)
	60	{
1e608e42	61	int i;
3c0ef626	62	static struct {
	63	char *pat;
	64	int bugs;
	65	} check[] = {
1e608e42	66	{ "OpenSSH-2.0*,"
	67	"OpenSSH-2.1*,"
	68	"OpenSSH_2.1*,"
	69	"OpenSSH_2.2*", SSH_OLD_SESSIONID\|SSH_BUG_BANNER\|
510132b6	70	SSH_OLD_DHGEX\|SSH_BUG_NOREKEY\|
dfddba3d	71	SSH_BUG_EXTEOF\|SSH_OLD_FORWARD_ADDR},
1e608e42	72	{ "OpenSSH_2.3.0*", SSH_BUG_BANNER\|SSH_BUG_BIGENDIANAES\|
510132b6	73	SSH_OLD_DHGEX\|SSH_BUG_NOREKEY\|
dfddba3d	74	SSH_BUG_EXTEOF\|SSH_OLD_FORWARD_ADDR},
1e608e42	75	{ "OpenSSH_2.3.*", SSH_BUG_BIGENDIANAES\|SSH_OLD_DHGEX\|
dfddba3d	76	SSH_BUG_NOREKEY\|SSH_BUG_EXTEOF\|
dfddba3d	77	SSH_OLD_FORWARD_ADDR},
1e608e42	78	{ "OpenSSH_2.5.0p1*,"
1e608e42	79	"OpenSSH_2.5.1p1*",
3c0ef626	80	SSH_BUG_BIGENDIANAES\|SSH_OLD_DHGEX\|
510132b6	81	SSH_BUG_NOREKEY\|SSH_BUG_EXTEOF\|
dfddba3d	82	SSH_OLD_FORWARD_ADDR},
1e608e42	83	{ "OpenSSH_2.5.0*,"
1e608e42	84	"OpenSSH_2.5.1*,"
510132b6	85	"OpenSSH_2.5.2*", SSH_OLD_DHGEX\|SSH_BUG_NOREKEY\|
dfddba3d	86	SSH_BUG_EXTEOF\|SSH_OLD_FORWARD_ADDR},
	87	{ "OpenSSH_2.5.3*", SSH_BUG_NOREKEY\|SSH_BUG_EXTEOF\|
	88	SSH_OLD_FORWARD_ADDR},
510132b6	89	{ "OpenSSH_2.*,"
510132b6	90	"OpenSSH_3.0*,"
dfddba3d	91	"OpenSSH_3.1*", SSH_BUG_EXTEOF\|SSH_OLD_FORWARD_ADDR},
dfddba3d	92	{ "OpenSSH_3.*", SSH_OLD_FORWARD_ADDR },
510132b6	93	{ "Sun_SSH_1.0*", SSH_BUG_NOREKEY\|SSH_BUG_EXTEOF},
1e608e42	94	{ "OpenSSH*", 0 },
	95	{ "MindTerm", 0 },
	96	{ "2.1.0*", SSH_BUG_SIGBLOB\|SSH_BUG_HMAC\|
3c0ef626	97	SSH_OLD_SESSIONID\|SSH_BUG_DEBUG\|
bfe49944	98	SSH_BUG_RSASIGMD5\|SSH_BUG_HBSERVICE\|
bfe49944	99	SSH_BUG_FIRSTKEX },
1e608e42	100	{ "2.1 *", SSH_BUG_SIGBLOB\|SSH_BUG_HMAC\|
3c0ef626	101	SSH_OLD_SESSIONID\|SSH_BUG_DEBUG\|
bfe49944	102	SSH_BUG_RSASIGMD5\|SSH_BUG_HBSERVICE\|
bfe49944	103	SSH_BUG_FIRSTKEX },
1e608e42	104	{ "2.0.13*,"
	105	"2.0.14*,"
	106	"2.0.15*,"
	107	"2.0.16*,"
	108	"2.0.17*,"
	109	"2.0.18*,"
	110	"2.0.19*", SSH_BUG_SIGBLOB\|SSH_BUG_HMAC\|
3c0ef626	111	SSH_OLD_SESSIONID\|SSH_BUG_DEBUG\|
	112	SSH_BUG_PKSERVICE\|SSH_BUG_X11FWD\|
	113	SSH_BUG_PKOK\|SSH_BUG_RSASIGMD5\|
	114	SSH_BUG_HBSERVICE\|SSH_BUG_OPENFAILURE\|
bfe49944	115	SSH_BUG_DUMMYCHAN\|SSH_BUG_FIRSTKEX },
1e608e42	116	{ "2.0.11*,"
1e608e42	117	"2.0.12*", SSH_BUG_SIGBLOB\|SSH_BUG_HMAC\|
3c0ef626	118	SSH_OLD_SESSIONID\|SSH_BUG_DEBUG\|
	119	SSH_BUG_PKSERVICE\|SSH_BUG_X11FWD\|
	120	SSH_BUG_PKAUTH\|SSH_BUG_PKOK\|
	121	SSH_BUG_RSASIGMD5\|SSH_BUG_OPENFAILURE\|
bfe49944	122	SSH_BUG_DUMMYCHAN\|SSH_BUG_FIRSTKEX },
1e608e42	123	{ "2.0.*", SSH_BUG_SIGBLOB\|SSH_BUG_HMAC\|
3c0ef626	124	SSH_OLD_SESSIONID\|SSH_BUG_DEBUG\|
	125	SSH_BUG_PKSERVICE\|SSH_BUG_X11FWD\|
	126	SSH_BUG_PKAUTH\|SSH_BUG_PKOK\|
	127	SSH_BUG_RSASIGMD5\|SSH_BUG_OPENFAILURE\|
bfe49944	128	SSH_BUG_DERIVEKEY\|SSH_BUG_DUMMYCHAN\|
bfe49944	129	SSH_BUG_FIRSTKEX },
1e608e42	130	{ "2.2.0*,"
1e608e42	131	"2.3.0*", SSH_BUG_HMAC\|SSH_BUG_DEBUG\|
bfe49944	132	SSH_BUG_RSASIGMD5\|SSH_BUG_FIRSTKEX },
	133	{ "2.3.*", SSH_BUG_DEBUG\|SSH_BUG_RSASIGMD5\|
	134	SSH_BUG_FIRSTKEX },
1e608e42	135	{ "2.4", SSH_OLD_SESSIONID }, /* Van Dyke */
0b90ac93	136	{ "2.*", SSH_BUG_DEBUG\|SSH_BUG_FIRSTKEX\|
0b90ac93	137	SSH_BUG_RFWD_ADDR },
1e608e42	138	{ "3.0.*", SSH_BUG_DEBUG },
	139	{ "3.0 SecureCRT*", SSH_OLD_SESSIONID },
	140	{ "1.7 SecureFX*", SSH_OLD_SESSIONID },
	141	{ "1.2.18*,"
	142	"1.2.19*,"
	143	"1.2.20*,"
	144	"1.2.21*,"
7cac2b65	145	"1.2.22*", SSH_BUG_IGNOREMSG },
510132b6	146	{ "1.3.2", / F-Secure */
7cac2b65	147	SSH_BUG_IGNOREMSG },
1e608e42	148	{ "SSH Compatible Server", /* Netscreen */
3c0ef626	149	SSH_BUG_PASSWORDPAD },
1e608e42	150	{ "OSU_0,"
	151	"OSU_1.0*,"
	152	"OSU_1.1*,"
	153	"OSU_1.2*,"
	154	"OSU_1.3*,"
	155	"OSU_1.4*,"
	156	"OSU_1.5alpha1*,"
	157	"OSU_1.5alpha2*,"
	158	"OSU_1.5alpha3*", SSH_BUG_PASSWORDPAD },
	159	{ "SSH_Version_Mapper",
3c0ef626	160	SSH_BUG_SCANNER },
d03f4262	161	{ "Probe-*",
d03f4262	162	SSH_BUG_PROBE },
3c0ef626	163	{ NULL, 0 }
3c0ef626	164	};
1e608e42	165
3c0ef626	166	/* process table, return first match */
3c0ef626	167	for (i = 0; check[i].pat; i++) {
1e608e42	168	if (match_pattern_list(version, check[i].pat,
1e608e42	169	strlen(check[i].pat), 0) == 1) {
3c0ef626	170	debug("match: %s pat %s", version, check[i].pat);
3c0ef626	171	datafellows = check[i].bugs;
473db5ab	172	/* Check to see if the remote side is OpenSSH and not HPN */
	173	if(strstr(version,"OpenSSH") != NULL)
	174	{
	175	if (strstr(version,"hpn") == NULL)
	176	{
	177	datafellows \|= SSH_BUG_LARGEWINDOW;
f713db99	178	debug("Remote is NON-HPN aware");
473db5ab	179	}
473db5ab	180	}
3c0ef626	181	return;
	182	}
	183	}
	184	debug("no match: %s", version);
	185	}
	186
	187	#define SEP ","
	188	int
	189	proto_spec(const char *spec)
	190	{
	191	char s, p, *q;
	192	int ret = SSH_PROTO_UNKNOWN;
	193
	194	if (spec == NULL)
	195	return ret;
	196	q = s = xstrdup(spec);
	197	for ((p = strsep(&q, SEP)); p && *p != '\0'; (p = strsep(&q, SEP))) {
1e608e42	198	switch (atoi(p)) {
3c0ef626	199	case 1:
	200	if (ret == SSH_PROTO_UNKNOWN)
	201	ret \|= SSH_PROTO_1_PREFERRED;
	202	ret \|= SSH_PROTO_1;
	203	break;
	204	case 2:
	205	ret \|= SSH_PROTO_2;
	206	break;
	207	default:
7cac2b65	208	logit("ignoring bad proto spec: '%s'.", p);
3c0ef626	209	break;
	210	}
	211	}
	212	xfree(s);
	213	return ret;
	214	}
	215
	216	char *
	217	compat_cipher_proposal(char *cipher_prop)
	218	{
1e608e42	219	Buffer b;
3c0ef626	220	char orig_prop, fix_ciphers;
3c0ef626	221	char cp, tmp;
3c0ef626	222
	223	if (!(datafellows & SSH_BUG_BIGENDIANAES))
	224	return(cipher_prop);
	225
1e608e42	226	buffer_init(&b);
3c0ef626	227	tmp = orig_prop = xstrdup(cipher_prop);
1e608e42	228	while ((cp = strsep(&tmp, ",")) != NULL) {
	229	if (strncmp(cp, "aes", 3) != 0) {
	230	if (buffer_len(&b) > 0)
	231	buffer_append(&b, ",", 1);
	232	buffer_append(&b, cp, strlen(cp));
3c0ef626	233	}
3c0ef626	234	}
1e608e42	235	buffer_append(&b, "\0", 1);
	236	fix_ciphers = xstrdup(buffer_ptr(&b));
	237	buffer_free(&b);
3c0ef626	238	xfree(orig_prop);
	239	debug2("Original cipher proposal: %s", cipher_prop);
	240	debug2("Compat cipher proposal: %s", fix_ciphers);
	241	if (!*fix_ciphers)
	242	fatal("No available ciphers found.");
	243
	244	return(fix_ciphers);
	245	}