[gssapi-openssh.git] / openssh / gss-genr.c

/*	$OpenBSD: gss-genr.c,v 1.1 2003/08/22 10:56:09 markus Exp $	*/

/*
 * Copyright (c) 2001-2003 Simon Wilkinson. 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"

#ifdef GSSAPI

#include "ssh.h"
#include "ssh2.h"
#include "xmalloc.h"
#include "buffer.h"
#include "bufaux.h"
#include "packet.h"
#include "compat.h"
#include <openssl/evp.h>
#include "cipher.h"
#include "kex.h"
#include "log.h"
#include "compat.h"
#include "monitor_wrap.h"
#include "canohost.h"

#include <netdb.h>

#include "ssh-gss.h"

typedef struct {
	char *encoded;
	gss_OID oid;
} ssh_gss_kex_mapping;
	
static ssh_gss_kex_mapping *gss_enc2oid;

/* Return a list of the gss-group1-sha1-x mechanisms supported by this
 * program.
 *
 * On the client side, we don't need to worry about whether we 'know'
 * about the mechanism or not - we assume that any mechanism that we've been
 * linked against is suitable for inclusion.
 *
 * XXX - We might want to make this configurable in the future, so as to
 * XXX - allow the user control over which mechanisms to use.
 */
 
char * 
ssh_gssapi_client_mechanisms(char *host) {
	gss_OID_set 	supported;
	OM_uint32	min_status;
	Buffer		buf;
	int 		i = 0;
	char 		*mechs;
	char		*encoded;
	int		enclen;
	char		digest[EVP_MAX_MD_SIZE];
	char		deroid[2];
	const EVP_MD	*evp_md = EVP_md5();
	EVP_MD_CTX	md;
	int 		oidpos=0;
	
	if (datafellows & SSH_OLD_GSSAPI) return NULL;
	
	gss_indicate_mechs(&min_status,&supported);
	if (datafellows & SSH_BUG_GSSAPI_BER) {
		gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
					*((supported->count*2)+1));
	} else {
		gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
					*(supported->count+1));
	}
	
	buffer_init(&buf);


	for (i=0;i<supported->count;i++) {

		gss_enc2oid[oidpos].encoded=NULL;
		
		if (supported->elements[i].length<128 &&
		    ssh_gssapi_check_mechanism(&(supported->elements[i]),host)) {

			/* Earlier versions of this code interpreted the
			 * spec incorrectly with regard to OID encoding. They
			 * also mis-encoded the krb5 OID. The following
			 * _temporary_ code interfaces with these broken
			 * servers */

			if (datafellows & SSH_BUG_GSSAPI_BER) {
				char *bodge=NULL;
				gss_OID_desc krb5oid={9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"};
				gss_OID_desc gsioid={9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"};
				
				if (supported->elements[i].length==krb5oid.length &&
				    memcmp(supported->elements[i].elements,
				    	   krb5oid.elements, krb5oid.length)==0) {
					bodge="Se3H81ismmOC3OE+FwYCiQ==";
				}
				
				if (supported->elements[i].length==gsioid.length &&
				    memcmp(supported->elements[i].elements,
				    	   gsioid.elements, gsioid.length)==0) {
					bodge="N3+k7/4wGxHyuP8Yxi4RhA==";
				}

				if (bodge) {				
					if (oidpos!=0) {
						buffer_put_char(&buf,',');
					}
				
					buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
					buffer_append(&buf, bodge, strlen(bodge));

					gss_enc2oid[oidpos].oid=&(supported->elements[i]);
					gss_enc2oid[oidpos].encoded=bodge;
			
					oidpos++;
				}
			}
			
			/* Add the required DER encoding octets and MD5 hash */
			deroid[0]=0x06; /* Object Identifier */
			deroid[1]=supported->elements[i].length;

			EVP_DigestInit(&md, evp_md);
			EVP_DigestUpdate(&md,deroid,2);
			EVP_DigestUpdate(&md,
					 supported->elements[i].elements,
					 supported->elements[i].length);
			EVP_DigestFinal(&md, digest, NULL);
			
			/* Base64 encode it */
			encoded=xmalloc(EVP_MD_size(evp_md)*2);
			enclen=__b64_ntop(digest, EVP_MD_size(evp_md),
				          encoded,EVP_MD_size(evp_md)*2);
			if (oidpos!=0) {
				buffer_put_char(&buf,',');
			}	
			buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
			buffer_append(&buf, encoded, enclen);

			debug("Mechanism encoded as %s",encoded);

			gss_enc2oid[oidpos].oid=&(supported->elements[i]);
			gss_enc2oid[oidpos].encoded=encoded;			
			oidpos++;
		}
	}
	gss_enc2oid[oidpos].oid=NULL;
	gss_enc2oid[oidpos].encoded=NULL;
	
	buffer_put_char(&buf,'\0');
	
	mechs=xmalloc(buffer_len(&buf));
	buffer_get(&buf,mechs,buffer_len(&buf));
	buffer_free(&buf);
	if (strlen(mechs)==0)
		return(NULL);
	else
		return(mechs);
}

gss_OID
ssh_gssapi_client_id_kex(Gssctxt *ctx, char *name) {
	int i=0;
	
	if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
		return(NULL);
	}
	
	name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the ID string */
	
	while (gss_enc2oid[i].encoded!=NULL &&
	       	strcmp(name,gss_enc2oid[i].encoded)!=0) {
	      	i++;
	}
	
	if (gss_enc2oid[i].oid!=NULL) {
		ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
	}

	return gss_enc2oid[i].oid;
}

/* Check that the OID in a data stream matches that in the context */
int
ssh_gssapi_check_oid(Gssctxt *ctx, void *data, size_t len)
{
	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	    ctx->oid->length == len &&
	    memcmp(ctx->oid->elements, data, len) == 0);
}

/* Set the contexts OID from a data stream */
void
ssh_gssapi_set_oid_data(Gssctxt *ctx, void *data, size_t len)
{
	if (ctx->oid != GSS_C_NO_OID) {
		xfree(ctx->oid->elements);
		xfree(ctx->oid);
	}
	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	ctx->oid->length = len;
	ctx->oid->elements = xmalloc(len);
	memcpy(ctx->oid->elements, data, len);
}

/* Set the contexts OID */
void
ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
{
	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
}

/* All this effort to report an error ... */
void
ssh_gssapi_error(Gssctxt *ctxt)
{
	debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
}

char *
ssh_gssapi_last_error(Gssctxt *ctxt,
		      OM_uint32 *major_status, OM_uint32 *minor_status)
{
	OM_uint32 lmin;
	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	OM_uint32 ctx;
	Buffer b;
	char *ret;

	buffer_init(&b);

	if (major_status != NULL)
		*major_status = ctxt->major;
	if (minor_status != NULL)
		*minor_status = ctxt->minor;

	ctx = 0;
	/* The GSSAPI error */
	do {
		gss_display_status(&lmin, ctxt->major,
		    GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);

		buffer_append(&b, msg.value, msg.length);
		buffer_put_char(&b, '\n');

		gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	/* The mechanism specific error */
	do {
		gss_display_status(&lmin, ctxt->minor,
		    GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);

		buffer_append(&b, msg.value, msg.length);
		buffer_put_char(&b, '\n');

		gss_release_buffer(&lmin, &msg);
	} while (ctx != 0);

	buffer_put_char(&b, '\0');
	ret = xmalloc(buffer_len(&b));
	buffer_get(&b, ret, buffer_len(&b));
	buffer_free(&b);
	return (ret);
}

/*
 * Initialise our GSSAPI context. We use this opaque structure to contain all
 * of the data which both the client and server need to persist across
 * {accept,init}_sec_context calls, so that when we do it from the userauth
 * stuff life is a little easier
 */
void
ssh_gssapi_build_ctx(Gssctxt **ctx)
{
	*ctx = xmalloc(sizeof (Gssctxt));
	(*ctx)->major = 0;
	(*ctx)->minor = 0;
	(*ctx)->context = GSS_C_NO_CONTEXT;
	(*ctx)->name = GSS_C_NO_NAME;
	(*ctx)->oid = GSS_C_NO_OID;
	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	(*ctx)->client = GSS_C_NO_NAME;
	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
}

/* Delete our context, providing it has been built correctly */
void
ssh_gssapi_delete_ctx(Gssctxt **ctx)
{
#if !defined(MECHGLUE)
	OM_uint32 ms;
#endif

	if ((*ctx) == NULL)
		return;
#if !defined(MECHGLUE) /* mechglue has some memory management issues */
	if ((*ctx)->context != GSS_C_NO_CONTEXT)
		gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
	if ((*ctx)->name != GSS_C_NO_NAME)
		gss_release_name(&ms, &(*ctx)->name);
	if ((*ctx)->oid != GSS_C_NO_OID) {
		xfree((*ctx)->oid->elements);
		xfree((*ctx)->oid);
		(*ctx)->oid = GSS_C_NO_OID;
	}
	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
		gss_release_cred(&ms, &(*ctx)->creds);
	if ((*ctx)->client != GSS_C_NO_NAME)
		gss_release_name(&ms, &(*ctx)->client);
	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
		gss_release_cred(&ms, &(*ctx)->client_creds);
#endif

	xfree(*ctx);
	*ctx = NULL;
}

/*
 * Wrapper to init_sec_context
 * Requires that the context contains:
 *	oid
 *	server name (from ssh_gssapi_import_name)
 */
OM_uint32
ssh_gssapi_init_ctx(Gssctxt *ctx, int deleg_creds, gss_buffer_desc *recv_tok,
    gss_buffer_desc* send_tok, OM_uint32 *flags)
{
	int deleg_flag = 0;

	if (deleg_creds) {
		deleg_flag = GSS_C_DELEG_FLAG;
		debug("Delegating credentials");
	}

	ctx->major = gss_init_sec_context(&ctx->minor,
	    GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	    GSS_C_MUTUAL_FLAG | GSS_C_INTEG_FLAG | deleg_flag,
	    0, NULL, recv_tok, NULL, send_tok, flags, NULL);

	if (GSS_ERROR(ctx->major))
		ssh_gssapi_error(ctx);

	return (ctx->major);
}

/* Create a service name for the given host */
OM_uint32
ssh_gssapi_import_name(Gssctxt *ctx, const char *host)
{
	gss_buffer_desc gssbuf;
	char *xhost;

	/* Make a copy of the host name, in case it was returned by a
	 * previous call to gethostbyname(). */	
	xhost = xstrdup(host);

	/* Make sure we have the FQDN. Some GSSAPI implementations don't do
	 * this for us themselves */
	resolve_localhost(&xhost);
	
	gssbuf.length = sizeof("host@") + strlen(xhost);
	gssbuf.value = xmalloc(gssbuf.length);
	snprintf(gssbuf.value, gssbuf.length, "host@%s", host);

	if ((ctx->major = gss_import_name(&ctx->minor,
	    &gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
		ssh_gssapi_error(ctx);

	xfree(xhost);
	xfree(gssbuf.value);
	return (ctx->major);
}

/* Acquire credentials for a server running on the current host.
 * Requires that the context structure contains a valid OID
 */

/* Returns a GSSAPI error code */
OM_uint32
ssh_gssapi_acquire_cred(Gssctxt *ctx)
{
	OM_uint32 status;
	char lname[MAXHOSTNAMELEN];
	gss_OID_set oidset;

	gss_create_empty_oid_set(&status, &oidset);
	gss_add_oid_set_member(&status, ctx->oid, &oidset);

	if (gethostname(lname, MAXHOSTNAMELEN))
		return (-1);

	if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
		return (ctx->major);

	if ((ctx->major = gss_acquire_cred(&ctx->minor,
	    ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
		ssh_gssapi_error(ctx);

	gss_release_oid_set(&status, &oidset);
	return (ctx->major);
}

OM_uint32
ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
	if (*ctx)
		ssh_gssapi_delete_ctx(ctx);
	ssh_gssapi_build_ctx(ctx);
	ssh_gssapi_set_oid(*ctx, oid);
	return (ssh_gssapi_acquire_cred(*ctx));
}

OM_uint32
ssh_gssapi_sign(Gssctxt *ctx, gss_buffer_desc *buffer, gss_buffer_desc *hash) {
	
	if ((ctx->major=gss_get_mic(&ctx->minor,ctx->context,
				    GSS_C_QOP_DEFAULT, buffer, hash))) {
		ssh_gssapi_error(ctx);
	}
	
	return(ctx->major);
}

int
ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
	Gssctxt * ctx = NULL;
	gss_buffer_desc token;
	OM_uint32 major,minor;
	
	ssh_gssapi_build_ctx(&ctx);
	ssh_gssapi_set_oid(ctx,oid);
	ssh_gssapi_import_name(ctx,host);
	major=ssh_gssapi_init_ctx(ctx,0, GSS_C_NO_BUFFER, &token, NULL);
	gss_release_buffer(&minor,&token);
	ssh_gssapi_delete_ctx(&ctx);
	return(!GSS_ERROR(major));
}

#endif /* GSSAPI */
Commit	Line	Data
7cac2b65	1	/* $OpenBSD: gss-genr.c,v 1.1 2003/08/22 10:56:09 markus Exp $ */
7cac2b65	2
5598e598	3	/*
7cac2b65	4	* Copyright (c) 2001-2003 Simon Wilkinson. All rights reserved.
7cac2b65	5	*
5598e598	6	* Redistribution and use in source and binary forms, with or without
	7	* modification, are permitted provided that the following conditions
	8	* are met:
	9	* 1. Redistributions of source code must retain the above copyright
	10	* notice, this list of conditions and the following disclaimer.
	11	* 2. Redistributions in binary form must reproduce the above copyright
	12	* notice, this list of conditions and the following disclaimer in the
	13	* documentation and/or other materials provided with the distribution.
	14	*
	15	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR `AS IS'' AND ANY EXPRESS OR
	16	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	17	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	18	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	19	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	20	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	24	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	*/
	26
	27	#include "includes.h"
	28
	29	#ifdef GSSAPI
	30
	31	#include "ssh.h"
	32	#include "ssh2.h"
	33	#include "xmalloc.h"
	34	#include "buffer.h"
	35	#include "bufaux.h"
	36	#include "packet.h"
	37	#include "compat.h"
	38	#include <openssl/evp.h>
	39	#include "cipher.h"
	40	#include "kex.h"
	41	#include "log.h"
905081a4	42	#include "compat.h"
b59afbfe	43	#include "monitor_wrap.h"
4dd35ca9	44	#include "canohost.h"
5598e598	45
	46	#include <netdb.h>
	47
	48	#include "ssh-gss.h"
	49
23987cb8	50	typedef struct {
	51	char *encoded;
	52	gss_OID oid;
	53	} ssh_gss_kex_mapping;
	54
	55	static ssh_gss_kex_mapping *gss_enc2oid;
5598e598	56
	57	/* Return a list of the gss-group1-sha1-x mechanisms supported by this
	58	* program.
	59	*
23987cb8	60	* On the client side, we don't need to worry about whether we 'know'
	61	* about the mechanism or not - we assume that any mechanism that we've been
	62	* linked against is suitable for inclusion.
5598e598	63	*
23987cb8	64	* XXX - We might want to make this configurable in the future, so as to
23987cb8	65	* XXX - allow the user control over which mechanisms to use.
5598e598	66	*/
	67
	68	char *
23987cb8	69	ssh_gssapi_client_mechanisms(char *host) {
5598e598	70	gss_OID_set supported;
23987cb8	71	OM_uint32 min_status;
5598e598	72	Buffer buf;
5598e598	73	int i = 0;
23987cb8	74	char *mechs;
	75	char *encoded;
	76	int enclen;
	77	char digest[EVP_MAX_MD_SIZE];
	78	char deroid[2];
	79	const EVP_MD *evp_md = EVP_md5();
	80	EVP_MD_CTX md;
	81	int oidpos=0;
	82
905081a4	83	if (datafellows & SSH_OLD_GSSAPI) return NULL;
905081a4	84
23987cb8	85	gss_indicate_mechs(&min_status,&supported);
	86	if (datafellows & SSH_BUG_GSSAPI_BER) {
	87	gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
	88	((supported->count2)+1));
	89	} else {
	90	gss_enc2oid=xmalloc(sizeof(ssh_gss_kex_mapping)
	91	*(supported->count+1));
	92	}
5598e598	93
23987cb8	94	buffer_init(&buf);
	95
	96
	97	for (i=0;i<supported->count;i++) {
	98
	99	gss_enc2oid[oidpos].encoded=NULL;
	100
	101	if (supported->elements[i].length<128 &&
	102	ssh_gssapi_check_mechanism(&(supported->elements[i]),host)) {
	103
	104	/* Earlier versions of this code interpreted the
e23e524c	105	* spec incorrectly with regard to OID encoding. They
	106	* also mis-encoded the krb5 OID. The following
	107	* _temporary_ code interfaces with these broken
	108	* servers */
23987cb8	109
	110	if (datafellows & SSH_BUG_GSSAPI_BER) {
	111	char *bodge=NULL;
	112	gss_OID_desc krb5oid={9, "\x2A\x86\x48\x86\xF7\x12\x01\x02\x02"};
	113	gss_OID_desc gsioid={9, "\x2B\x06\x01\x04\x01\x9B\x50\x01\x01"};
	114
	115	if (supported->elements[i].length==krb5oid.length &&
	116	memcmp(supported->elements[i].elements,
	117	krb5oid.elements, krb5oid.length)==0) {
	118	bodge="Se3H81ismmOC3OE+FwYCiQ==";
	119	}
	120
	121	if (supported->elements[i].length==gsioid.length &&
	122	memcmp(supported->elements[i].elements,
	123	gsioid.elements, gsioid.length)==0) {
	124	bodge="N3+k7/4wGxHyuP8Yxi4RhA==";
	125	}
	126
	127	if (bodge) {
	128	if (oidpos!=0) {
	129	buffer_put_char(&buf,',');
	130	}
	131
	132	buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
	133	buffer_append(&buf, bodge, strlen(bodge));
	134
	135	gss_enc2oid[oidpos].oid=&(supported->elements[i]);
	136	gss_enc2oid[oidpos].encoded=bodge;
	137
	138	oidpos++;
d4ab470d	139	}
d4ab470d	140	}
23987cb8	141
	142	/* Add the required DER encoding octets and MD5 hash */
	143	deroid[0]=0x06; /* Object Identifier */
	144	deroid[1]=supported->elements[i].length;
	145
	146	EVP_DigestInit(&md, evp_md);
	147	EVP_DigestUpdate(&md,deroid,2);
	148	EVP_DigestUpdate(&md,
e23e524c	149	supported->elements[i].elements,
e23e524c	150	supported->elements[i].length);
23987cb8	151	EVP_DigestFinal(&md, digest, NULL);
	152
	153	/* Base64 encode it */
	154	encoded=xmalloc(EVP_MD_size(evp_md)*2);
	155	enclen=__b64_ntop(digest, EVP_MD_size(evp_md),
	156	encoded,EVP_MD_size(evp_md)*2);
	157	if (oidpos!=0) {
	158	buffer_put_char(&buf,',');
	159	}
	160	buffer_append(&buf, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1);
	161	buffer_append(&buf, encoded, enclen);
	162
	163	debug("Mechanism encoded as %s",encoded);
	164
	165	gss_enc2oid[oidpos].oid=&(supported->elements[i]);
	166	gss_enc2oid[oidpos].encoded=encoded;
	167	oidpos++;
d4ab470d	168	}
23987cb8	169	}
	170	gss_enc2oid[oidpos].oid=NULL;
	171	gss_enc2oid[oidpos].encoded=NULL;
5598e598	172
	173	buffer_put_char(&buf,'\0');
	174
	175	mechs=xmalloc(buffer_len(&buf));
	176	buffer_get(&buf,mechs,buffer_len(&buf));
	177	buffer_free(&buf);
	178	if (strlen(mechs)==0)
23987cb8	179	return(NULL);
5598e598	180	else
23987cb8	181	return(mechs);
	182	}
	183
	184	gss_OID
	185	ssh_gssapi_client_id_kex(Gssctxt ctx, char name) {
	186	int i=0;
	187
	188	if (strncmp(name, KEX_GSS_SHA1, sizeof(KEX_GSS_SHA1)-1) !=0) {
	189	return(NULL);
	190	}
	191
	192	name+=sizeof(KEX_GSS_SHA1)-1; /* Move to the start of the ID string */
	193
	194	while (gss_enc2oid[i].encoded!=NULL &&
	195	strcmp(name,gss_enc2oid[i].encoded)!=0) {
	196	i++;
	197	}
	198
	199	if (gss_enc2oid[i].oid!=NULL) {
	200	ssh_gssapi_set_oid(ctx,gss_enc2oid[i].oid);
	201	}
	202
	203	return gss_enc2oid[i].oid;
5598e598	204	}
5598e598	205
23987cb8	206	/* Check that the OID in a data stream matches that in the context */
7cac2b65	207	int
	208	ssh_gssapi_check_oid(Gssctxt ctx, void data, size_t len)
	209	{
	210	return (ctx != NULL && ctx->oid != GSS_C_NO_OID &&
	211	ctx->oid->length == len &&
	212	memcmp(ctx->oid->elements, data, len) == 0);
23987cb8	213	}
7cac2b65	214
5598e598	215	/* Set the contexts OID from a data stream */
7cac2b65	216	void
	217	ssh_gssapi_set_oid_data(Gssctxt ctx, void data, size_t len)
	218	{
	219	if (ctx->oid != GSS_C_NO_OID) {
	220	xfree(ctx->oid->elements);
	221	xfree(ctx->oid);
	222	}
	223	ctx->oid = xmalloc(sizeof(gss_OID_desc));
	224	ctx->oid->length = len;
	225	ctx->oid->elements = xmalloc(len);
	226	memcpy(ctx->oid->elements, data, len);
5598e598	227	}
	228
	229	/* Set the contexts OID */
7cac2b65	230	void
	231	ssh_gssapi_set_oid(Gssctxt *ctx, gss_OID oid)
	232	{
	233	ssh_gssapi_set_oid_data(ctx, oid->elements, oid->length);
5598e598	234	}
5598e598	235
23987cb8	236	/* All this effort to report an error ... */
23987cb8	237	void
7cac2b65	238	ssh_gssapi_error(Gssctxt *ctxt)
	239	{
	240	debug("%s", ssh_gssapi_last_error(ctxt, NULL, NULL));
5598e598	241	}
5598e598	242
23987cb8	243	char *
7cac2b65	244	ssh_gssapi_last_error(Gssctxt *ctxt,
	245	OM_uint32 major_status, OM_uint32 minor_status)
	246	{
23987cb8	247	OM_uint32 lmin;
7cac2b65	248	gss_buffer_desc msg = GSS_C_EMPTY_BUFFER;
	249	OM_uint32 ctx;
	250	Buffer b;
	251	char *ret;
	252
	253	buffer_init(&b);
	254
	255	if (major_status != NULL)
	256	*major_status = ctxt->major;
	257	if (minor_status != NULL)
	258	*minor_status = ctxt->minor;
	259
	260	ctx = 0;
5598e598	261	/* The GSSAPI error */
7cac2b65	262	do {
	263	gss_display_status(&lmin, ctxt->major,
	264	GSS_C_GSS_CODE, ctxt->oid, &ctx, &msg);
	265
	266	buffer_append(&b, msg.value, msg.length);
	267	buffer_put_char(&b, '\n');
	268
	269	gss_release_buffer(&lmin, &msg);
	270	} while (ctx != 0);
	271
	272	/* The mechanism specific error */
	273	do {
	274	gss_display_status(&lmin, ctxt->minor,
	275	GSS_C_MECH_CODE, ctxt->oid, &ctx, &msg);
	276
	277	buffer_append(&b, msg.value, msg.length);
	278	buffer_put_char(&b, '\n');
	279
	280	gss_release_buffer(&lmin, &msg);
	281	} while (ctx != 0);
	282
	283	buffer_put_char(&b, '\0');
	284	ret = xmalloc(buffer_len(&b));
	285	buffer_get(&b, ret, buffer_len(&b));
	286	buffer_free(&b);
	287	return (ret);
5598e598	288	}
5598e598	289
7cac2b65	290	/*
7cac2b65	291	* Initialise our GSSAPI context. We use this opaque structure to contain all
5598e598	292	* of the data which both the client and server need to persist across
	293	* {accept,init}_sec_context calls, so that when we do it from the userauth
	294	* stuff life is a little easier
	295	*/
	296	void
b59afbfe	297	ssh_gssapi_build_ctx(Gssctxt **ctx)
5598e598	298	{
7cac2b65	299	*ctx = xmalloc(sizeof (Gssctxt));
	300	(*ctx)->major = 0;
	301	(*ctx)->minor = 0;
	302	(*ctx)->context = GSS_C_NO_CONTEXT;
	303	(*ctx)->name = GSS_C_NO_NAME;
	304	(*ctx)->oid = GSS_C_NO_OID;
	305	(*ctx)->creds = GSS_C_NO_CREDENTIAL;
	306	(*ctx)->client = GSS_C_NO_NAME;
	307	(*ctx)->client_creds = GSS_C_NO_CREDENTIAL;
5598e598	308	}
	309
	310	/* Delete our context, providing it has been built correctly */
	311	void
b59afbfe	312	ssh_gssapi_delete_ctx(Gssctxt **ctx)
5598e598	313	{
9eeaa28e	314	#if !defined(MECHGLUE)
5598e598	315	OM_uint32 ms;
9eeaa28e	316	#endif
7cac2b65	317
7cac2b65	318	if ((*ctx) == NULL)
b59afbfe	319	return;
d4ab470d	320	#if !defined(MECHGLUE) /* mechglue has some memory management issues */
7cac2b65	321	if ((*ctx)->context != GSS_C_NO_CONTEXT)
7cac2b65	322	gss_delete_sec_context(&ms, &(*ctx)->context, GSS_C_NO_BUFFER);
b59afbfe	323	if ((*ctx)->name != GSS_C_NO_NAME)
7cac2b65	324	gss_release_name(&ms, &(*ctx)->name);
b59afbfe	325	if ((*ctx)->oid != GSS_C_NO_OID) {
	326	xfree((*ctx)->oid->elements);
	327	xfree((*ctx)->oid);
	328	(*ctx)->oid = GSS_C_NO_OID;
5598e598	329	}
b59afbfe	330	if ((*ctx)->creds != GSS_C_NO_CREDENTIAL)
7cac2b65	331	gss_release_cred(&ms, &(*ctx)->creds);
b59afbfe	332	if ((*ctx)->client != GSS_C_NO_NAME)
7cac2b65	333	gss_release_name(&ms, &(*ctx)->client);
b59afbfe	334	if ((*ctx)->client_creds != GSS_C_NO_CREDENTIAL)
7cac2b65	335	gss_release_cred(&ms, &(*ctx)->client_creds);
d4ab470d	336	#endif
7cac2b65	337
b59afbfe	338	xfree(*ctx);
7cac2b65	339	*ctx = NULL;
5598e598	340	}
5598e598	341
7cac2b65	342	/*
7cac2b65	343	* Wrapper to init_sec_context
5598e598	344	* Requires that the context contains:
5598e598	345	* oid
7cac2b65	346	* server name (from ssh_gssapi_import_name)
5598e598	347	*/
7cac2b65	348	OM_uint32
5598e598	349	ssh_gssapi_init_ctx(Gssctxt ctx, int deleg_creds, gss_buffer_desc recv_tok,
7cac2b65	350	gss_buffer_desc* send_tok, OM_uint32 *flags)
5598e598	351	{
5598e598	352	int deleg_flag = 0;
7cac2b65	353
5598e598	354	if (deleg_creds) {
7cac2b65	355	deleg_flag = GSS_C_DELEG_FLAG;
5598e598	356	debug("Delegating credentials");
5598e598	357	}
7cac2b65	358
	359	ctx->major = gss_init_sec_context(&ctx->minor,
	360	GSS_C_NO_CREDENTIAL, &ctx->context, ctx->name, ctx->oid,
	361	GSS_C_MUTUAL_FLAG \| GSS_C_INTEG_FLAG \| deleg_flag,
	362	0, NULL, recv_tok, NULL, send_tok, flags, NULL);
	363
	364	if (GSS_ERROR(ctx->major))
	365	ssh_gssapi_error(ctx);
	366
	367	return (ctx->major);
5598e598	368	}
5598e598	369
5598e598	370	/* Create a service name for the given host */
5598e598	371	OM_uint32
7cac2b65	372	ssh_gssapi_import_name(Gssctxt ctx, const char host)
7cac2b65	373	{
23987cb8	374	gss_buffer_desc gssbuf;
4dd35ca9	375	char *xhost;
7cac2b65	376
5598e598	377	/* Make a copy of the host name, in case it was returned by a
e23e524c	378	* previous call to gethostbyname(). */
5598e598	379	xhost = xstrdup(host);
5598e598	380
23987cb8	381	/* Make sure we have the FQDN. Some GSSAPI implementations don't do
e23e524c	382	* this for us themselves */
1df48666	383	resolve_localhost(&xhost);
23987cb8	384
7cac2b65	385	gssbuf.length = sizeof("host@") + strlen(xhost);
	386	gssbuf.value = xmalloc(gssbuf.length);
	387	snprintf(gssbuf.value, gssbuf.length, "host@%s", host);
	388
	389	if ((ctx->major = gss_import_name(&ctx->minor,
	390	&gssbuf, GSS_C_NT_HOSTBASED_SERVICE, &ctx->name)))
23987cb8	391	ssh_gssapi_error(ctx);
7cac2b65	392
1c828c5c	393	xfree(xhost);
5598e598	394	xfree(gssbuf.value);
7cac2b65	395	return (ctx->major);
5598e598	396	}
	397
	398	/* Acquire credentials for a server running on the current host.
	399	* Requires that the context structure contains a valid OID
b59afbfe	400	*/
7cac2b65	401
b59afbfe	402	/* Returns a GSSAPI error code */
5598e598	403	OM_uint32
7cac2b65	404	ssh_gssapi_acquire_cred(Gssctxt *ctx)
7cac2b65	405	{
23987cb8	406	OM_uint32 status;
5598e598	407	char lname[MAXHOSTNAMELEN];
5598e598	408	gss_OID_set oidset;
5598e598	409
7cac2b65	410	gss_create_empty_oid_set(&status, &oidset);
	411	gss_add_oid_set_member(&status, ctx->oid, &oidset);
	412
	413	if (gethostname(lname, MAXHOSTNAMELEN))
	414	return (-1);
	415
	416	if (GSS_ERROR(ssh_gssapi_import_name(ctx, lname)))
	417	return (ctx->major);
	418
	419	if ((ctx->major = gss_acquire_cred(&ctx->minor,
	420	ctx->name, 0, oidset, GSS_C_ACCEPT, &ctx->creds, NULL, NULL)))
23987cb8	421	ssh_gssapi_error(ctx);
7cac2b65	422
23987cb8	423	gss_release_oid_set(&status, &oidset);
7cac2b65	424	return (ctx->major);
	425	}
	426
	427	OM_uint32
	428	ssh_gssapi_server_ctx(Gssctxt **ctx, gss_OID oid) {
	429	if (*ctx)
	430	ssh_gssapi_delete_ctx(ctx);
	431	ssh_gssapi_build_ctx(ctx);
	432	ssh_gssapi_set_oid(*ctx, oid);
	433	return (ssh_gssapi_acquire_cred(*ctx));
5598e598	434	}
b59afbfe	435
	436	OM_uint32
	437	ssh_gssapi_sign(Gssctxt ctx, gss_buffer_desc buffer, gss_buffer_desc *hash) {
5598e598	438
23987cb8	439	if ((ctx->major=gss_get_mic(&ctx->minor,ctx->context,
b59afbfe	440	GSS_C_QOP_DEFAULT, buffer, hash))) {
23987cb8	441	ssh_gssapi_error(ctx);
b59afbfe	442	}
b59afbfe	443
23987cb8	444	return(ctx->major);
b59afbfe	445	}
b59afbfe	446
23987cb8	447	int
	448	ssh_gssapi_check_mechanism(gss_OID oid, char *host) {
	449	Gssctxt * ctx = NULL;
	450	gss_buffer_desc token;
	451	OM_uint32 major,minor;
	452
	453	ssh_gssapi_build_ctx(&ctx);
	454	ssh_gssapi_set_oid(ctx,oid);
	455	ssh_gssapi_import_name(ctx,host);
	456	major=ssh_gssapi_init_ctx(ctx,0, GSS_C_NO_BUFFER, &token, NULL);
b59afbfe	457	gss_release_buffer(&minor,&token);
23987cb8	458	ssh_gssapi_delete_ctx(&ctx);
23987cb8	459	return(!GSS_ERROR(major));
b59afbfe	460	}
f001f132	461
5598e598	462	#endif /* GSSAPI */