kssl.c

	if (keyblk == NULL)
                {
		printf("%s, keyblk==0\n", label);
		return;
		}
#ifdef KRB5_HEIMDAL
	printf("%s\n\t[et%d:%d]: ", label, keyblk->keytype,
					   keyblk->keyvalue->length);
	for (i=0; i < (int)keyblk->keyvalue->length; i++)
                {
		printf("%02x",(unsigned char *)(keyblk->keyvalue->contents)[i]);
		}
	printf("\n");
#else
	printf("%s\n\t[et%d:%d]: ", label, keyblk->enctype, keyblk->length);
	for (i=0; i < (int)keyblk->length; i++)
                {
		printf("%02x",keyblk->contents[i]);
		}
	printf("\n");
#endif
        }


/*	Display contents of krb5_principal_data struct, for debugging
**	(krb5_principal is typedef'd == krb5_principal_data *)
*/
static void
print_krb5_princ(char *label, krb5_principal_data *princ)
        {
	int i, ui, uj;

	printf("%s principal Realm: ", label);
	if (princ == NULL)  return;
	for (ui=0; ui < (int)princ->realm.length; ui++)  putchar(princ->realm.data[ui]);
	printf(" (nametype %d) has %d strings:\n", princ->type,princ->length);
	for (i=0; i < (int)princ->length; i++)
                {
		printf("\t%d [%d]: ", i, princ->data[i].length);
		for (uj=0; uj < (int)princ->data[i].length; uj++)  {
			putchar(princ->data[i].data[uj]);
			}
		printf("\n");
		}
	return;
        }


/*	Given krb5 service (typically "kssl") and hostname in kssl_ctx,
**	Return encrypted Kerberos ticket for service @ hostname.
**	If authenp is non-NULL, also return encrypted authenticator,
**	whose data should be freed by caller.
**	(Originally was: Create Kerberos AP_REQ message for SSL Client.)
**
**	19990628	VRS 	Started; Returns Kerberos AP_REQ message.
**	20010409	VRS 	Modified for RFC2712; Returns enc tkt.
**	20010606	VRS 	May also return optional authenticator.
*/
krb5_error_code
kssl_cget_tkt(	/* UPDATE */	KSSL_CTX *kssl_ctx,
                /* OUT    */	krb5_data **enc_ticketp,
                /* UPDATE */	krb5_data *authenp,
                /* OUT    */	KSSL_ERR *kssl_err)
	{
	krb5_error_code		krb5rc = KRB5KRB_ERR_GENERIC;
	krb5_context		krb5context = NULL;
	krb5_auth_context	krb5auth_context = NULL;
	krb5_ccache 		krb5ccdef = NULL;
	krb5_creds		krb5creds, *krb5credsp = NULL;
	krb5_data		krb5_app_req;

	kssl_err_set(kssl_err, 0, "");
	memset((char *)&krb5creds, 0, sizeof(krb5creds));

	if (!kssl_ctx)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "No kssl_ctx defined.\n");
		goto err;
		}
	else if (!kssl_ctx->service_host)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "kssl_ctx service_host undefined.\n");
		goto err;
		}

	if ((krb5rc = krb5_init_context(&krb5context)) != 0)
                {
		BIO_snprintf(kssl_err->text,KSSL_ERR_MAX,
                        "krb5_init_context() fails: %d\n", krb5rc);
		kssl_err->reason = SSL_R_KRB5_C_INIT;
		goto err;
		}

	if ((krb5rc = krb5_sname_to_principal(krb5context,
                kssl_ctx->service_host,
                (kssl_ctx->service_name)? kssl_ctx->service_name: KRB5SVC,
                KRB5_NT_SRV_HST, &krb5creds.server)) != 0)
                {
		BIO_snprintf(kssl_err->text,KSSL_ERR_MAX,
                        "krb5_sname_to_principal() fails for %s/%s\n",
                        kssl_ctx->service_host,
                        (kssl_ctx->service_name)? kssl_ctx->service_name:
						  KRB5SVC);
		kssl_err->reason = SSL_R_KRB5_C_INIT;
		goto err;
		}

	if ((krb5rc = krb5_cc_default(krb5context, &krb5ccdef)) != 0)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_C_CC_PRINC,
                        "krb5_cc_default fails.\n");
		goto err;
		}

	if ((krb5rc = krb5_cc_get_principal(krb5context, krb5ccdef,
                &krb5creds.client)) != 0)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_C_CC_PRINC,
                        "krb5_cc_get_principal() fails.\n");
		goto err;
		}

	if ((krb5rc = krb5_get_credentials(krb5context, 0, krb5ccdef,
                &krb5creds, &krb5credsp)) != 0)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_C_GET_CRED,
                        "krb5_get_credentials() fails.\n");
		goto err;
		}

	*enc_ticketp = &krb5credsp->ticket;
#ifdef KRB5_HEIMDAL
	kssl_ctx->enctype = krb5credsp->session.keytype;
#else
	kssl_ctx->enctype = krb5credsp->keyblock.enctype;
#endif

	krb5rc = KRB5KRB_ERR_GENERIC;
	/*	caller should free data of krb5_app_req  */
	/*  20010406 VRS deleted for real KerberosWrapper
	**  20010605 VRS reinstated to offer Authenticator to KerberosWrapper
	*/
	krb5_app_req.length = 0;
	if (authenp)
                {
		krb5_data	krb5in_data;
		const unsigned char	*p;
		long		arlen;
		KRB5_APREQBODY	*ap_req;

		authenp->length = 0;
		krb5in_data.data = NULL;
		krb5in_data.length = 0;
		if ((krb5rc = krb5_mk_req_extended(krb5context,
			&krb5auth_context, 0, &krb5in_data, krb5credsp,
			&krb5_app_req)) != 0)
			{
			kssl_err_set(kssl_err, SSL_R_KRB5_C_MK_REQ,
				"krb5_mk_req_extended() fails.\n");
			goto err;
			}

		arlen = krb5_app_req.length;
		p = (unsigned char *)krb5_app_req.data;
		ap_req = (KRB5_APREQBODY *) d2i_KRB5_APREQ(NULL, &p, arlen);
		if (ap_req)
			{
			authenp->length = i2d_KRB5_ENCDATA(
					ap_req->authenticator, NULL);
			if (authenp->length  && 
				(authenp->data = malloc(authenp->length)))
				{
				unsigned char	*adp = (unsigned char *)authenp->data;
				authenp->length = i2d_KRB5_ENCDATA(
						ap_req->authenticator, &adp);
				}
			}

		if (ap_req)  KRB5_APREQ_free((KRB5_APREQ *) ap_req);
		if (krb5_app_req.length)  
                        kssl_krb5_free_data_contents(krb5context,&krb5_app_req);
		}
#ifdef KRB5_HEIMDAL
	if (kssl_ctx_setkey(kssl_ctx, &krb5credsp->session))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_C_INIT,
                        "kssl_ctx_setkey() fails.\n");
		}
#else
	if (kssl_ctx_setkey(kssl_ctx, &krb5credsp->keyblock))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_C_INIT,
                        "kssl_ctx_setkey() fails.\n");
		}
#endif
	else	krb5rc = 0;

 err:
#ifdef KSSL_DEBUG
	kssl_ctx_show(kssl_ctx);
#endif	/* KSSL_DEBUG */

	if (krb5creds.client)	krb5_free_principal(krb5context,
							krb5creds.client);
	if (krb5creds.server)	krb5_free_principal(krb5context,
							krb5creds.server);
	if (krb5auth_context)	krb5_auth_con_free(krb5context,
							krb5auth_context);
	if (krb5context)	krb5_free_context(krb5context);
	return (krb5rc);
	}


/*  Given d2i_-decoded asn1ticket, allocate and return a new krb5_ticket.
**  Return Kerberos error code and kssl_err struct on error.
**  Allocates krb5_ticket and krb5_principal; caller should free these.
**
**	20010410	VRS	Implemented krb5_decode_ticket() as
**				old_krb5_decode_ticket(). Missing from MIT1.0.6.
**	20010615	VRS 	Re-cast as openssl/asn1 d2i_*() functions.
**				Re-used some of the old krb5_decode_ticket()
**				code here.  This tkt should alloc/free just
**				like the real thing.
*/
static krb5_error_code
kssl_TKT2tkt(	/* IN     */	krb5_context	krb5context,
		/* IN     */	KRB5_TKTBODY	*asn1ticket,
		/* OUT    */	krb5_ticket	**krb5ticket,
		/* OUT    */	KSSL_ERR *kssl_err  )
        {
        krb5_error_code			krb5rc = KRB5KRB_ERR_GENERIC;
	krb5_ticket 			*new5ticket = NULL;
	ASN1_GENERALSTRING		*gstr_svc, *gstr_host;

	*krb5ticket = NULL;

	if (asn1ticket == NULL  ||  asn1ticket->realm == NULL  ||
		asn1ticket->sname == NULL  || 
		sk_ASN1_GENERALSTRING_num(asn1ticket->sname->namestring) < 2)
		{
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"Null field in asn1ticket.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		return KRB5KRB_ERR_GENERIC;
		}

	if ((new5ticket = (krb5_ticket *) calloc(1, sizeof(krb5_ticket)))==NULL)
		{
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"Unable to allocate new krb5_ticket.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		return ENOMEM;		/*  or  KRB5KRB_ERR_GENERIC;	*/
		}

	gstr_svc  = sk_ASN1_GENERALSTRING_value(asn1ticket->sname->namestring, 0);
	gstr_host = sk_ASN1_GENERALSTRING_value(asn1ticket->sname->namestring, 1);

	if ((krb5rc = kssl_build_principal_2(krb5context,
			&new5ticket->server,
			asn1ticket->realm->length, (char *)asn1ticket->realm->data,
			gstr_svc->length,  (char *)gstr_svc->data,
			gstr_host->length, (char *)gstr_host->data)) != 0)
		{
		free(new5ticket);
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"Error building ticket server principal.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		return krb5rc;		/*  or  KRB5KRB_ERR_GENERIC;	*/
		}

	krb5_princ_type(krb5context, new5ticket->server) =
			asn1ticket->sname->nametype->data[0];
	new5ticket->enc_part.enctype = asn1ticket->encdata->etype->data[0];
	new5ticket->enc_part.kvno = asn1ticket->encdata->kvno->data[0];
	new5ticket->enc_part.ciphertext.length =
			asn1ticket->encdata->cipher->length;
	if ((new5ticket->enc_part.ciphertext.data =
		calloc(1, asn1ticket->encdata->cipher->length)) == NULL)
		{
		free(new5ticket);
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"Error allocating cipher in krb5ticket.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		return KRB5KRB_ERR_GENERIC;
		}
	else
		{
		memcpy(new5ticket->enc_part.ciphertext.data,
			asn1ticket->encdata->cipher->data,
			asn1ticket->encdata->cipher->length);
		}

	*krb5ticket = new5ticket;
	return 0;
	}


/*	Given krb5 service name in KSSL_CTX *kssl_ctx (typically "kssl"),
**		and krb5 AP_REQ message & message length,
**	Return Kerberos session key and client principle
**		to SSL Server in KSSL_CTX *kssl_ctx.
**
**	19990702	VRS 	Started.
*/
krb5_error_code
kssl_sget_tkt(	/* UPDATE */	KSSL_CTX		*kssl_ctx,
		/* IN     */	krb5_data		*indata,
		/* OUT    */	krb5_ticket_times	*ttimes,
		/* OUT    */	KSSL_ERR		*kssl_err  )
        {
        krb5_error_code			krb5rc = KRB5KRB_ERR_GENERIC;
        static krb5_context		krb5context = NULL;
	static krb5_auth_context	krb5auth_context = NULL;
	krb5_ticket 			*krb5ticket = NULL;
	KRB5_TKTBODY 			*asn1ticket = NULL;
	const unsigned char		*p;
	krb5_keytab 			krb5keytab = NULL;
	krb5_keytab_entry		kt_entry;
	krb5_principal			krb5server;
        krb5_rcache                     rcache = NULL;

	kssl_err_set(kssl_err, 0, "");

	if (!kssl_ctx)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
			"No kssl_ctx defined.\n");
		goto err;
		}

#ifdef KSSL_DEBUG
	printf("in kssl_sget_tkt(%s)\n", kstring(kssl_ctx->service_name));
#endif	/* KSSL_DEBUG */

	if (!krb5context  &&  (krb5rc = krb5_init_context(&krb5context)))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "krb5_init_context() fails.\n");
		goto err;
		}
	if (krb5auth_context  &&
		(krb5rc = krb5_auth_con_free(krb5context, krb5auth_context)))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "krb5_auth_con_free() fails.\n");
		goto err;
		}
	else  krb5auth_context = NULL;
	if (!krb5auth_context  &&
		(krb5rc = krb5_auth_con_init(krb5context, &krb5auth_context)))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "krb5_auth_con_init() fails.\n");
		goto err;
		}

 
	if ((krb5rc = krb5_auth_con_getrcache(krb5context, krb5auth_context,
		&rcache)))
		{
 		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
			"krb5_auth_con_getrcache() fails.\n");
 		goto err;
		}
 
	if ((krb5rc = krb5_sname_to_principal(krb5context, NULL,
                (kssl_ctx->service_name)? kssl_ctx->service_name: KRB5SVC,
                KRB5_NT_SRV_HST, &krb5server)) != 0)
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                        "krb5_sname_to_principal() fails.\n");
		goto err;
		}

	if (rcache == NULL) 
                {
                if ((krb5rc = krb5_get_server_rcache(krb5context,
			krb5_princ_component(krb5context, krb5server, 0),
			&rcache)))
                        {
		        kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
                                "krb5_get_server_rcache() fails.\n");
                  	goto err;
                        }
                }

        if ((krb5rc = krb5_auth_con_setrcache(krb5context, krb5auth_context, rcache)))
                {
                kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
			"krb5_auth_con_setrcache() fails.\n");
                goto err;
                }


	/*	kssl_ctx->keytab_file == NULL ==> use Kerberos default
	*/
	if (kssl_ctx->keytab_file)
		{
		krb5rc = krb5_kt_resolve(krb5context, kssl_ctx->keytab_file,
                        &krb5keytab);
		if (krb5rc)
			{
			kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT,
				"krb5_kt_resolve() fails.\n");
			goto err;
			}
		}
	else
		{
                krb5rc = krb5_kt_default(krb5context,&krb5keytab);
                if (krb5rc)
			{
			kssl_err_set(kssl_err, SSL_R_KRB5_S_INIT, 
				"krb5_kt_default() fails.\n");
			goto err;
			}
		}

	/*	Actual Kerberos5 krb5_recvauth() has initial conversation here
	**	o	check KRB5_SENDAUTH_BADAUTHVERS
	**		unless KRB5_RECVAUTH_SKIP_VERSION
	**	o	check KRB5_SENDAUTH_BADAPPLVERS
	**	o	send "0" msg if all OK
	*/

	/*  20010411 was using AP_REQ instead of true KerberosWrapper
	**
	**  if ((krb5rc = krb5_rd_req(krb5context, &krb5auth_context,
	**			&krb5in_data, krb5server, krb5keytab,
	**			&ap_option, &krb5ticket)) != 0)  { Error }
	*/

	p = (unsigned char *)indata->data;
	if ((asn1ticket = (KRB5_TKTBODY *) d2i_KRB5_TICKET(NULL, &p,
						(long) indata->length)) == NULL)
		{
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"d2i_KRB5_TICKET() ASN.1 decode failure.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		goto err;
		}
	
	/* Was:  krb5rc = krb5_decode_ticket(krb5in_data,&krb5ticket)) != 0) */
	if ((krb5rc = kssl_TKT2tkt(krb5context, asn1ticket, &krb5ticket,
					kssl_err)) != 0)
		{
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"Error converting ASN.1 ticket to krb5_ticket.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		goto err;
		}

	if (! krb5_principal_compare(krb5context, krb5server,
						  krb5ticket->server))  {
		krb5rc = KRB5_PRINC_NOMATCH;
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"server principal != ticket principal\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		goto err;
		}
	if ((krb5rc = krb5_kt_get_entry(krb5context, krb5keytab,
			krb5ticket->server, krb5ticket->enc_part.kvno,
			krb5ticket->enc_part.enctype, &kt_entry)) != 0)  {
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"krb5_kt_get_entry() fails with %x.\n", krb5rc);
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		goto err;
		}
	if ((krb5rc = krb5_decrypt_tkt_part(krb5context, &kt_entry.key,
			krb5ticket)) != 0)  {
		BIO_snprintf(kssl_err->text, KSSL_ERR_MAX,
			"krb5_decrypt_tkt_part() failed.\n");
		kssl_err->reason = SSL_R_KRB5_S_RD_REQ;
		goto err;
		}
	else  {
		krb5_kt_free_entry(krb5context, &kt_entry);
#ifdef KSSL_DEBUG
		{
		int i; krb5_address **paddr = krb5ticket->enc_part2->caddrs;
		printf("Decrypted ticket fields:\n");
		printf("\tflags: %X, transit-type: %X",
			krb5ticket->enc_part2->flags,
			krb5ticket->enc_part2->transited.tr_type);
		print_krb5_data("\ttransit-data: ",
			&(krb5ticket->enc_part2->transited.tr_contents));
		printf("\tcaddrs: %p, authdata: %p\n",
			krb5ticket->enc_part2->caddrs,
			krb5ticket->enc_part2->authorization_data);
		if (paddr)
			{
			printf("\tcaddrs:\n");
			for (i=0; paddr[i] != NULL; i++)
				{
				krb5_data d;
				d.length=paddr[i]->length;
				d.data=paddr[i]->contents;
				print_krb5_data("\t\tIP: ", &d);
				}
			}
		printf("\tstart/auth/end times: %d / %d / %d\n",
			krb5ticket->enc_part2->times.starttime,
			krb5ticket->enc_part2->times.authtime,
			krb5ticket->enc_part2->times.endtime);
		}
#endif	/* KSSL_DEBUG */
		}

	krb5rc = KRB5_NO_TKT_SUPPLIED;
	if (!krb5ticket  ||	!krb5ticket->enc_part2  ||
                !krb5ticket->enc_part2->client  ||
                !krb5ticket->enc_part2->client->data  ||
                !krb5ticket->enc_part2->session)
                {
                kssl_err_set(kssl_err, SSL_R_KRB5_S_BAD_TICKET,
                        "bad ticket from krb5_rd_req.\n");
		}
	else if (kssl_ctx_setprinc(kssl_ctx, KSSL_CLIENT,
		 &krb5ticket->enc_part2->client->realm,
		 krb5ticket->enc_part2->client->data,
		 krb5ticket->enc_part2->client->length))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_BAD_TICKET,
                        "kssl_ctx_setprinc() fails.\n");
		}
	else if (kssl_ctx_setkey(kssl_ctx, krb5ticket->enc_part2->session))
                {
		kssl_err_set(kssl_err, SSL_R_KRB5_S_BAD_TICKET,
                        "kssl_ctx_setkey() fails.\n");
		}
	else if (krb5ticket->enc_part2->flags & TKT_FLG_INVALID)
                {
		krb5rc = KRB5KRB_AP_ERR_TKT_INVALID;
                kssl_err_set(kssl_err, SSL_R_KRB5_S_BAD_TICKET,
                        "invalid ticket from krb5_rd_req.\n");
		}
	else	krb5rc = 0;

	kssl_ctx->enctype	= krb5ticket->enc_part.enctype;
	ttimes->authtime	= krb5ticket->enc_part2->times.authtime;
	ttimes->starttime	= krb5ticket->enc_part2->times.starttime;
	ttimes->endtime 	= krb5ticket->enc_part2->times.endtime;
	ttimes->renew_till	= krb5ticket->enc_part2->times.renew_till;

 err:
#ifdef KSSL_DEBUG
	kssl_ctx_show(kssl_ctx);
#endif	/* KSSL_DEBUG */

	if (asn1ticket) 	KRB5_TICKET_free((KRB5_TICKET *) asn1ticket);
        if (krb5keytab)         krb5_kt_close(krb5context, krb5keytab);
	if (krb5ticket) 	krb5_free_ticket(krb5context, krb5ticket);
	if (krb5server) 	krb5_free_principal(krb5context, krb5server);
	return (krb5rc);
        }


/*	Allocate & return a new kssl_ctx struct.
*/
KSSL_CTX	*
kssl_ctx_new(void)
        {
	return ((KSSL_CTX *) kssl_calloc(1, sizeof(KSSL_CTX)));
        }


/*	Frees a kssl_ctx struct and any allocated memory it holds.
**	Returns NULL.
*/
KSSL_CTX	*
kssl_ctx_free(KSSL_CTX *kssl_ctx)
        {
	if (kssl_ctx == NULL)  return kssl_ctx;

	if (kssl_ctx->key)  		OPENSSL_cleanse(kssl_ctx->key,
							      kssl_ctx->length);
	if (kssl_ctx->key)  		kssl_free(kssl_ctx->key);
	if (kssl_ctx->client_princ) 	kssl_free(kssl_ctx->client_princ);
	if (kssl_ctx->service_host) 	kssl_free(kssl_ctx->service_host);
	if (kssl_ctx->service_name) 	kssl_free(kssl_ctx->service_name);
	if (kssl_ctx->keytab_file) 	kssl_free(kssl_ctx->keytab_file);

	kssl_free(kssl_ctx);
	return (KSSL_CTX *) NULL;
        }


/*	Given an array of (krb5_data *) entity (and optional realm),
**	set the plain (char *) client_princ or service_host member
**	of the kssl_ctx struct.
*/
krb5_error_code
kssl_ctx_setprinc(KSSL_CTX *kssl_ctx, int which,
        krb5_data *realm, krb5_data *entity, int nentities)
        {
	char	**princ;
	int 	length;
	int i;

	if (kssl_ctx == NULL  ||  entity == NULL)  return KSSL_CTX_ERR;

	switch (which)
                {
        case KSSL_CLIENT:	princ = &kssl_ctx->client_princ;	break;
        case KSSL_SERVER:	princ = &kssl_ctx->service_host;	break;
        default:		return KSSL_CTX_ERR;			break;
		}
	if (*princ)  kssl_free(*princ);

	/* Add up all the entity->lengths */
	length = 0;
	for (i=0; i < nentities; i++)
		{
		length += entity[i].length;
		}
	/* Add in space for the '/' character(s) (if any) */
	length += nentities-1;
	/* Space for the ('@'+realm+NULL | NULL) */
	length += ((realm)? realm->length + 2: 1);

	if ((*princ = kssl_calloc(1, length)) == NULL)
		return KSSL_CTX_ERR;
	else
		{
		for (i = 0; i < nentities; i++)
			{
			strncat(*princ, entity[i].data, entity[i].length);
			if (i < nentities-1)
				{
				strcat (*princ, "/");
				}
			}
		if (realm)
                        {
			strcat (*princ, "@");
			(void) strncat(*princ, realm->data, realm->length);
			}
		}

	return KSSL_CTX_OK;
        }


/*	Set one of the plain (char *) string members of the kssl_ctx struct.
**	Default values should be:
**		which == KSSL_SERVICE	=>	"khost" (KRB5SVC)
**		which == KSSL_KEYTAB	=>	"/etc/krb5.keytab" (KRB5KEYTAB)
*/
krb5_error_code
kssl_ctx_setstring(KSSL_CTX *kssl_ctx, int which, char *text)
        {
	char	**string;

	if (!kssl_ctx)  return KSSL_CTX_ERR;

	switch (which)
                {
        case KSSL_SERVICE:	string = &kssl_ctx->service_name;	break;
        case KSSL_SERVER:	string = &kssl_ctx->service_host;	break;
        case KSSL_CLIENT:	string = &kssl_ctx->client_princ;	break;
        case KSSL_KEYTAB:	string = &kssl_ctx->keytab_file;	break;
        default:		return KSSL_CTX_ERR;			break;
		}
	if (*string)  kssl_free(*string);

	if (!text)
                {
		*string = '\0';
		return KSSL_CTX_OK;
		}

	if ((*string = kssl_calloc(1, strlen(text) + 1)) == NULL)
		return KSSL_CTX_ERR;
	else
		strcpy(*string, text);

	return KSSL_CTX_OK;
        }


/*	Copy the Kerberos session key from a (krb5_keyblock *) to a kssl_ctx
**	struct.  Clear kssl_ctx->key if Kerberos session key is NULL.
*/
krb5_error_code
kssl_ctx_setkey(KSSL_CTX *kssl_ctx, krb5_keyblock *session)
        {
	int 		length;
	krb5_enctype	enctype;
	krb5_octet FAR	*contents = NULL;

	if (!kssl_ctx)  return KSSL_CTX_ERR;

	if (kssl_ctx->key)
                {
		OPENSSL_cleanse(kssl_ctx->key, kssl_ctx->length);
		kssl_free(kssl_ctx->key);
		}

	if (session)
                {

#ifdef KRB5_HEIMDAL
		length = session->keyvalue->length;
		enctype = session->keytype;
		contents = session->keyvalue->contents;
#else
		length = session->length;
		enctype = session->enctype;
		contents = session->contents;
#endif
		kssl_ctx->enctype = enctype;
		kssl_ctx->length  = length;
		}
	else
                {
		kssl_ctx->enctype = ENCTYPE_UNKNOWN;
		kssl_ctx->length  = 0;
		return KSSL_CTX_OK;
		}

	if ((kssl_ctx->key =
                (krb5_octet FAR *) kssl_calloc(1, kssl_ctx->length)) == NULL)
                {
		kssl_ctx->length  = 0;
		return KSSL_CTX_ERR;
		}
	else
		memcpy(kssl_ctx->key, contents, length);

	return KSSL_CTX_OK;
        }


/*	Display contents of kssl_ctx struct
*/
void
kssl_ctx_show(KSSL_CTX *kssl_ctx)
        {
	int 	i;

	printf("kssl_ctx: ");
	if (kssl_ctx == NULL)
                {
		printf("NULL\n");
		return;
		}
	else
		printf("%p\n", (void *)kssl_ctx);

	printf("\tservice:\t%s\n",
                (kssl_ctx->service_name)? kssl_ctx->service_name: "NULL");
	printf("\tclient:\t%s\n",
                (kssl_ctx->client_princ)? kssl_ctx->client_princ: "NULL");
	printf("\tserver:\t%s\n",
                (kssl_ctx->service_host)? kssl_ctx->service_host: "NULL");
	printf("\tkeytab:\t%s\n",
                (kssl_ctx->keytab_file)? kssl_ctx->keytab_file: "NULL");
	printf("\tkey [%d:%d]:\t",
                kssl_ctx->enctype, kssl_ctx->length);

	for (i=0; i < kssl_ctx->length  &&  kssl_ctx->key; i++)
                {
		printf("%02x", kssl_ctx->key[i]);
		}
	printf("\n");
	return;
        }

    int 
    kssl_keytab_is_available(KSSL_CTX *kssl_ctx)
{
    krb5_context		krb5context = NULL;
    krb5_keytab 		krb5keytab = NULL;
    krb5_keytab_entry           entry;
    krb5_principal              princ = NULL;
    krb5_error_code  		krb5rc = KRB5KRB_ERR_GENERIC;
    int rc = 0;

    if ((krb5rc = krb5_init_context(&krb5context)))
        return(0);

    /*	kssl_ctx->keytab_file == NULL ==> use Kerberos default
    */
    if (kssl_ctx->keytab_file)
    {
        krb5rc = krb5_kt_resolve(krb5context, kssl_ctx->keytab_file,
                                  &krb5keytab);
        if (krb5rc)
            goto exit;
    }
    else
    {
        krb5rc = krb5_kt_default(krb5context,&krb5keytab);
        if (krb5rc)
            goto exit;
    }

    /* the host key we are looking for */
    krb5rc = krb5_sname_to_principal(krb5context, NULL, 
                                     kssl_ctx->service_name ? kssl_ctx->service_name: KRB5SVC,
                                     KRB5_NT_SRV_HST, &princ);

    if (krb5rc)
	goto exit;

    krb5rc = krb5_kt_get_entry(krb5context, krb5keytab, 
                                princ,
                                0 /* IGNORE_VNO */,
                                0 /* IGNORE_ENCTYPE */,
                                &entry);
    if ( krb5rc == KRB5_KT_NOTFOUND ) {
        rc = 1;
        goto exit;
    } else if ( krb5rc )
        goto exit;
    
    krb5_kt_free_entry(krb5context, &entry);
    rc = 1;

  exit:
    if (krb5keytab)     krb5_kt_close(krb5context, krb5keytab);
    if (princ)          krb5_free_principal(krb5context, princ);
    if (krb5context)	krb5_free_context(krb5context);
    return(rc);
}

int 
kssl_tgt_is_available(KSSL_CTX *kssl_ctx)
        {
        krb5_error_code		krb5rc = KRB5KRB_ERR_GENERIC;
        krb5_context		krb5context = NULL;
        krb5_ccache 		krb5ccdef = NULL;
        krb5_creds		krb5creds, *krb5credsp = NULL;
        int                     rc = 0;

        memset((char *)&krb5creds, 0, sizeof(krb5creds));

        if (!kssl_ctx)
            return(0);

        if (!kssl_ctx->service_host)
            return(0);

        if ((krb5rc = krb5_init_context(&krb5context)) != 0)
            goto err;

        if ((krb5rc = krb5_sname_to_principal(krb5context,
                                              kssl_ctx->service_host,
                                              (kssl_ctx->service_name)? kssl_ctx->service_name: KRB5SVC,
                                              KRB5_NT_SRV_HST, &krb5creds.server)) != 0)
            goto err;

        if ((krb5rc = krb5_cc_default(krb5context, &krb5ccdef)) != 0)
            goto err;

        if ((krb5rc = krb5_cc_get_principal(krb5context, krb5ccdef,
                                             &krb5creds.client)) != 0)
            goto err;

        if ((krb5rc = krb5_get_credentials(krb5context, 0, krb5ccdef,
                                            &krb5creds, &krb5credsp)) != 0)
            goto err;

        rc = 1;

      err:
#ifdef KSSL_DEBUG
	kssl_ctx_show(kssl_ctx);
#endif	/* KSSL_DEBUG */

	if (krb5creds.client)	krb5_free_principal(krb5context, krb5creds.client);
	if (krb5creds.server)	krb5_free_principal(krb5context, krb5creds.server);
	if (krb5context)	krb5_free_context(krb5context);
        return(rc);
	}

#if !defined(OPENSSL_SYS_WINDOWS) && !defined(OPENSSL_SYS_WIN32)
void kssl_krb5_free_data_contents(krb5_context context, krb5_data *data)
	{
#ifdef KRB5_HEIMDAL
	data->length = 0;
        if (data->data)
            free(data->data);
#elif defined(KRB5_MIT_OLD11)
	if (data->data)  {
		krb5_xfree(data->data);
		data->data = 0;
		}
#else
	krb5_free_data_contents(NULL, data);
#endif
	}
#endif /* !OPENSSL_SYS_WINDOWS && !OPENSSL_SYS_WIN32 */


/*  Given pointers to KerberosTime and struct tm structs, convert the
**  KerberosTime string to struct tm.  Note that KerberosTime is a
**  ASN1_GENERALIZEDTIME value, constrained to GMT with no fractional
**  seconds as defined in RFC 1510.
**  Return pointer to the (partially) filled in struct tm on success,
**  return NULL on failure.
*/
static struct tm *k_gmtime(ASN1_GENERALIZEDTIME *gtime, struct tm *k_tm)
	{
	char 		c, *p;

	if (!k_tm)  return NULL;
	if (gtime == NULL  ||  gtime->length < 14)  return NULL;
	if (gtime->data == NULL)  return NULL;

	p = (char *)&gtime->data[14];

	c = *p;	 *p = '\0';  p -= 2;  k_tm->tm_sec  = atoi(p);      *(p+2) = c;
	c = *p;	 *p = '\0';  p -= 2;  k_tm->tm_min  = atoi(p);      *(p+2) = c;
	c = *p;	 *p = '\0';  p -= 2;  k_tm->tm_hour = atoi(p);      *(p+2) = c;
	c = *p;	 *p = '\0';  p -= 2;  k_tm->tm_mday = atoi(p);      *(p+2) = c;
	c = *p;	 *p = '\0';  p -= 2;  k_tm->tm_mon  = atoi(p)-1;    *(p+2) = c;
	c = *p;	 *p = '\0';  p -= 4;  k_tm->tm_year = atoi(p)-1900; *(p+4) = c;

	return k_tm;
	}


/*  Helper function for kssl_validate_times().
**  We need context->clockskew, but krb5_context is an opaque struct.
**  So we try to sneek the clockskew out through the replay cache.
**	If that fails just return a likely default (300 seconds).
*/
static krb5_deltat get_rc_clockskew(krb5_context context)
	{
	krb5_rcache 	rc;
	krb5_deltat 	clockskew;

	if (krb5_rc_default(context, &rc))  return KSSL_CLOCKSKEW;
	if (krb5_rc_initialize(context, rc, 0))  return KSSL_CLOCKSKEW;
	if (krb5_rc_get_lifespan(context, rc, &clockskew))  {
		clockskew = KSSL_CLOCKSKEW;
		}
	(void) krb5_rc_destroy(context, rc);
	return clockskew;
	}


/*  kssl_validate_times() combines (and more importantly exposes)
**  the MIT KRB5 internal function krb5_validate_times() and the
**  in_clock_skew() macro.  The authenticator client time is checked
**  to be within clockskew secs of the current time and the current
**  time is checked to be within the ticket start and expire times.
**  Either check may be omitted by supplying a NULL value.
**  Returns 0 for valid times, SSL_R_KRB5* error codes otherwise.
**  See Also: (Kerberos source)/krb5/lib/krb5/krb/valid_times.c
**  20010420 VRS
*/
krb5_error_code  kssl_validate_times(	krb5_timestamp atime,
					krb5_ticket_times *ttimes)
	{
	krb5_deltat 	skew;
	krb5_timestamp	start, now;
	krb5_error_code	rc;
	krb5_context	context;

	if ((rc = krb5_init_context(&context)))	 return SSL_R_KRB5_S_BAD_TICKET;
	skew = get_rc_clockskew(context); 
	if ((rc = krb5_timeofday(context,&now))) return SSL_R_KRB5_S_BAD_TICKET;
	krb5_free_context(context);

	if (atime  &&  labs(atime - now) >= skew)  return SSL_R_KRB5_S_TKT_SKEW;

	if (! ttimes)  return 0;

	start = (ttimes->starttime != 0)? ttimes->starttime: ttimes->authtime;
	if (start - now > skew)  return SSL_R_KRB5_S_TKT_NYV;
	if ((now - ttimes->endtime) > skew)  return SSL_R_KRB5_S_TKT_EXPIRED;

#ifdef KSSL_DEBUG
	printf("kssl_validate_times: %d |<-  | %d - %d | < %d  ->| %d\n",
		start, atime, now, skew, ttimes->endtime);
#endif	/* KSSL_DEBUG */

	return 0;
	}


/*  Decode and decrypt given DER-encoded authenticator, then pass
**  authenticator ctime back in *atimep (or 0 if time unavailable).
**  Returns krb5_error_code and kssl_err on error.  A NULL 
**  authenticator (authentp->length == 0) is not considered an error.
**  Note that kssl_check_authent() makes use of the KRB5 session key;
**  you must call kssl_sget_tkt() to get the key before calling this routine.
*/
krb5_error_code  kssl_check_authent(
			/* IN     */	KSSL_CTX	*kssl_ctx,
                        /* IN     */   	krb5_data	*authentp,
			/* OUT    */	krb5_timestamp	*atimep,
			/* OUT    */    KSSL_ERR	*kssl_err  )
	{
        krb5_error_code		krb5rc = 0;