text: /* tls_g.c - Handle tls/ssl using GNUTLS. */
  /* $OpenLDAP$ */
  /* This work is part of OpenLDAP Software <http://www.openldap.org/>.
   *
   * Copyright 2008-2015 The OpenLDAP Foundation.
   * All rights reserved.
   *
   * Redistribution and use in source and binary forms, with or without
   * modification, are permitted only as authorized by the OpenLDAP
   * Public License.
   *
   * A copy of this license is available in the file LICENSE in the
   * top-level directory of the distribution or, alternatively, at
   * <http://www.OpenLDAP.org/license.html>.
   */
  /* ACKNOWLEDGEMENTS: GNUTLS support written by Howard Chu and
   * Emily Backes; sponsored by The Written Word (thewrittenword.com)
   * and Stanford University (stanford.edu).
   */
  
  #include "portable.h"
  
  #ifdef HAVE_GNUTLS
  
  #include "ldap_config.h"
  
  #include <stdio.h>
  
  #include <ac/stdlib.h>
  #include <ac/errno.h>
  #include <ac/socket.h>
  #include <ac/string.h>
  #include <ac/ctype.h>
  #include <ac/time.h>
  #include <ac/unistd.h>
  #include <ac/param.h>
  #include <ac/dirent.h>
  #include <sys/stat.h>
  #include <fcntl.h>
  
  #include "ldap-int.h"
  #include "ldap-tls.h"
  
  #include <gnutls/gnutls.h>
  #include <gnutls/x509.h>
  
  #define DH_BITS	(1024)
  
  typedef struct tlsg_ctx {
  	struct ldapoptions *lo;
  	gnutls_certificate_credentials_t cred;
  	gnutls_dh_params_t dh_params;
  	unsigned long verify_depth;
  	int refcount;
  	gnutls_priority_t prios;
  #ifdef LDAP_R_COMPILE
  	ldap_pvt_thread_mutex_t ref_mutex;
  #endif
  } tlsg_ctx;
  
  typedef struct tlsg_session {
  	gnutls_session_t session;
  	tlsg_ctx *ctx;
  	struct berval peer_der_dn;
  } tlsg_session;
  
  static int tlsg_parse_ciphers( tlsg_ctx *ctx, char *suites );
  static int tlsg_cert_verify( tlsg_session *s );
  
  #ifdef LDAP_R_COMPILE
  
  static int
  tlsg_mutex_init( void **priv )
  {
  	int err = 0;
  	ldap_pvt_thread_mutex_t *lock = LDAP_MALLOC( sizeof( ldap_pvt_thread_mutex_t ));
  
  	if ( !lock )
  		err = ENOMEM;
  	if ( !err ) {
  		err = ldap_pvt_thread_mutex_init( lock );
  		if ( err )
  			LDAP_FREE( lock );
  		else
  			*priv = lock;
  	}
  	return err;
  }
  
  static int
  tlsg_mutex_destroy( void **lock )
  {
  	int err = ldap_pvt_thread_mutex_destroy( *lock );
  	LDAP_FREE( *lock );
  	return err;
  }
  
  static int
  tlsg_mutex_lock( void **lock )
  {
  	return ldap_pvt_thread_mutex_lock( *lock );
  }
  
  static int
  tlsg_mutex_unlock( void **lock )
  {
  	return ldap_pvt_thread_mutex_unlock( *lock );
  }
  
  static void
  tlsg_thr_init( void )
  {
  	gnutls_global_set_mutex (tlsg_mutex_init,
  		tlsg_mutex_destroy,
  		tlsg_mutex_lock,
  		tlsg_mutex_unlock);
  }
  #endif /* LDAP_R_COMPILE */
  
  /*
   * Initialize TLS subsystem. Should be called only once.
   */
  static int
  tlsg_init( void )
  {
  	gnutls_global_init();
  	return 0;
  }
  
  /*
   * Tear down the TLS subsystem. Should only be called once.
   */
  static void
  tlsg_destroy( void )
  {
  	gnutls_global_deinit();
  }
  
  static tls_ctx *
  tlsg_ctx_new ( struct ldapoptions *lo )
  {
  	tlsg_ctx *ctx;
  
  	ctx = ber_memcalloc ( 1, sizeof (*ctx) );
  	if ( ctx ) {
  		ctx->lo = lo;
  		if ( gnutls_certificate_allocate_credentials( &ctx->cred )) {
  			ber_memfree( ctx );
  			return NULL;
  		}
  		ctx->refcount = 1;
  		gnutls_priority_init( &ctx->prios, "NORMAL", NULL );
  #ifdef LDAP_R_COMPILE
  		ldap_pvt_thread_mutex_init( &ctx->ref_mutex );
  #endif
  	}
  	return (tls_ctx *)ctx;
  }
  
  static void
  tlsg_ctx_ref( tls_ctx *ctx )
  {
  	tlsg_ctx *c = (tlsg_ctx *)ctx;
  	LDAP_MUTEX_LOCK( &c->ref_mutex );
  	c->refcount++;
  	LDAP_MUTEX_UNLOCK( &c->ref_mutex );
  }
  
  static void
  tlsg_ctx_free ( tls_ctx *ctx )
  {
  	tlsg_ctx *c = (tlsg_ctx *)ctx;
  	int refcount;
  
  	if ( !c ) return;
  
  	LDAP_MUTEX_LOCK( &c->ref_mutex );
  	refcount = --c->refcount;
  	LDAP_MUTEX_UNLOCK( &c->ref_mutex );
  	if ( refcount )
  		return;
  	gnutls_priority_deinit( c->prios );
  	gnutls_certificate_free_credentials( c->cred );
  	ber_memfree ( c );
  }
  
  static int
  tlsg_getfile( const char *path, gnutls_datum_t *buf )
  {
  	int rc = -1, fd;
  	struct stat st;
  
  	fd = open( path, O_RDONLY );
  	if ( fd >= 0 && fstat( fd, &st ) == 0 ) {
  		buf->size = st.st_size;
  		buf->data = LDAP_MALLOC( st.st_size + 1 );
  		if ( buf->data ) {
  			rc = read( fd, buf->data, st.st_size );
  			close( fd );
  			if ( rc < st.st_size )
  				rc = -1;
  			else
  				rc = 0;
  		}
  	}
  	return rc;
  }
  
  /* This is the GnuTLS default */
  #define	VERIFY_DEPTH	6
  
  /*
   * initialize a new TLS context
   */
  static int
  tlsg_ctx_init( struct ldapoptions *lo, struct ldaptls *lt, int is_server )
  {
  	tlsg_ctx *ctx = lo->ldo_tls_ctx;
  	int rc;
  
   	if ( lo->ldo_tls_ciphersuite &&
  		tlsg_parse_ciphers( ctx, lt->lt_ciphersuite )) {
   		Debug( LDAP_DEBUG_ANY,
   			   "TLS: could not set cipher list %s.\n",
   			   lo->ldo_tls_ciphersuite, 0, 0 );
  		return -1;
   	}
  
  	if (lo->ldo_tls_cacertdir != NULL) {
  		Debug( LDAP_DEBUG_ANY, 
  		       "TLS: warning: cacertdir not implemented for gnutls\n",
  		       NULL, NULL, NULL );
  	}
  
  	if (lo->ldo_tls_cacertfile != NULL) {
  		rc = gnutls_certificate_set_x509_trust_file( 
  			ctx->cred,
  			lt->lt_cacertfile,
  			GNUTLS_X509_FMT_PEM );
  		if ( rc < 0 ) return -1;
  	}
  
  	if ( lo->ldo_tls_certfile && lo->ldo_tls_keyfile ) {
  		gnutls_x509_privkey_t key;
  		gnutls_datum_t buf;
  		gnutls_x509_crt_t certs[VERIFY_DEPTH];
  		unsigned int max = VERIFY_DEPTH;
  
  		rc = gnutls_x509_privkey_init( &key );
  		if ( rc ) return -1;
  
  		/* OpenSSL builds the cert chain for us, but GnuTLS
  		 * expects it to be present in the certfile. If it's
  		 * not, we have to build it ourselves. So we have to
  		 * do some special checks here...
  		 */
  		rc = tlsg_getfile( lt->lt_keyfile, &buf );
  		if ( rc ) return -1;
  		rc = gnutls_x509_privkey_import( key, &buf,
  			GNUTLS_X509_FMT_PEM );
  		LDAP_FREE( buf.data );
  		if ( rc < 0 ) return rc;
  
  		rc = tlsg_getfile( lt->lt_certfile, &buf );
  		if ( rc ) return -1;
  		rc = gnutls_x509_crt_list_import( certs, &max, &buf,
  			GNUTLS_X509_FMT_PEM, 0 );
  		LDAP_FREE( buf.data );
  		if ( rc < 0 ) return rc;
  
  		/* If there's only one cert and it's not self-signed,
  		 * then we have to build the cert chain.
  		 */
  		if ( max == 1 && !gnutls_x509_crt_check_issuer( certs[0], certs[0] )) {
  			unsigned int i;
  			for ( i = 1; i<VERIFY_DEPTH; i++ ) {
  				if ( gnutls_certificate_get_issuer( ctx->cred, certs[i-1], &certs[i], 0 ))
  					break;
  				max++;
  				/* If this CA is self-signed, we're done */
  				if ( gnutls_x509_crt_check_issuer( certs[i], certs[i] ))
  					break;
  			}
  		}
  		rc = gnutls_certificate_set_x509_key( ctx->cred, certs, max, key );
  		if ( rc ) return -1;
  	} else if ( lo->ldo_tls_certfile || lo->ldo_tls_keyfile ) {
  		Debug( LDAP_DEBUG_ANY, 
  		       "TLS: only one of certfile and keyfile specified\n",
  		       NULL, NULL, NULL );
  		return -1;
  	}
  
  	if ( lo->ldo_tls_dhfile ) {
  		Debug( LDAP_DEBUG_ANY, 
  		       "TLS: warning: ignoring dhfile\n", 
  		       NULL, NULL, NULL );
  	}
  
  	if ( lo->ldo_tls_crlfile ) {
  		rc = gnutls_certificate_set_x509_crl_file( 
  			ctx->cred,
  			lt->lt_crlfile,
  			GNUTLS_X509_FMT_PEM );
  		if ( rc < 0 ) return -1;
  		rc = 0;
  	}
  
  	/* FIXME: ITS#5992 - this should go be configurable,
  	 * and V1 CA certs should be phased out ASAP.
  	 */
  	gnutls_certificate_set_verify_flags( ctx->cred,
  		GNUTLS_VERIFY_ALLOW_X509_V1_CA_CRT );
  
  	if ( is_server ) {
  		gnutls_dh_params_init(&ctx->dh_params);
  		gnutls_dh_params_generate2(ctx->dh_params, DH_BITS);
  	}
  	return 0;
  }
  
  static tls_session *
  tlsg_session_new ( tls_ctx * ctx, int is_server )
  {
  	tlsg_ctx *c = (tlsg_ctx *)ctx;
  	tlsg_session *session;
  
  	session = ber_memcalloc ( 1, sizeof (*session) );
  	if ( !session )
  		return NULL;
  
  	session->ctx = c;
  	gnutls_init( &session->session, is_server ? GNUTLS_SERVER : GNUTLS_CLIENT );
  	gnutls_priority_set( session->session, c->prios );
  	if ( c->cred )
  		gnutls_credentials_set( session->session, GNUTLS_CRD_CERTIFICATE, c->cred );
  	
  	if ( is_server ) {
  		int flag = 0;
  		if ( c->lo->ldo_tls_require_cert ) {
  			flag = GNUTLS_CERT_REQUEST;
  			if ( c->lo->ldo_tls_require_cert == LDAP_OPT_X_TLS_DEMAND ||
  				c->lo->ldo_tls_require_cert == LDAP_OPT_X_TLS_HARD )
  				flag = GNUTLS_CERT_REQUIRE;
  			gnutls_certificate_server_set_request( session->session, flag );
  		}
  	}
  	return (tls_session *)session;
  } 
  
  static int
  tlsg_session_accept( tls_session *session )
  {
  	tlsg_session *s = (tlsg_session *)session;
  	int rc;
  
  	rc = gnutls_handshake( s->session );
  	if ( rc == 0 && s->ctx->lo->ldo_tls_require_cert != LDAP_OPT_X_TLS_NEVER ) {
  		const gnutls_datum_t *peer_cert_list;
  		unsigned int list_size;
  
  		peer_cert_list = gnutls_certificate_get_peers( s->session, 
  						&list_size );
  		if ( !peer_cert_list && s->ctx->lo->ldo_tls_require_cert == LDAP_OPT_X_TLS_TRY ) 
  			rc = 0;
  		else {
  			rc = tlsg_cert_verify( s );
  			if ( rc && s->ctx->lo->ldo_tls_require_cert == LDAP_OPT_X_TLS_ALLOW )
  				rc = 0;
  		}
  	}
  	return rc;
  }
  
  static int
  tlsg_session_connect( LDAP *ld, tls_session *session )
  {
  	return tlsg_session_accept( session);
  }
  
  static int
  tlsg_session_upflags( Sockbuf *sb, tls_session *session, int rc )
  {
  	tlsg_session *s = (tlsg_session *)session;
  
  	if ( rc != GNUTLS_E_INTERRUPTED && rc != GNUTLS_E_AGAIN )
  		return 0;
  
  	switch (gnutls_record_get_direction (s->session)) {
  	case 0: 
  		sb->sb_trans_needs_read = 1;
  		return 1;
  	case 1:
  		sb->sb_trans_needs_write = 1;
  		return 1;
  	}
  	return 0;
  }
  
  static char *
  tlsg_session_errmsg( tls_session *sess, int rc, char *buf, size_t len )
  {
  	return (char *)gnutls_strerror( rc );
  }
  
  static void
  tlsg_x509_cert_dn( struct berval *cert, struct berval *dn, int get_subject )
  {
  	BerElementBuffer berbuf;
  	BerElement *ber = (BerElement *)&berbuf;
  	ber_tag_t tag;
  	ber_len_t len;
  	ber_int_t i;
  
  	ber_init2( ber, cert, LBER_USE_DER );
  	tag = ber_skip_tag( ber, &len );	/* Sequence */
  	tag = ber_skip_tag( ber, &len );	/* Sequence */
  	tag = ber_peek_tag( ber, &len );	/* Context + Constructed (version) */
  	if ( tag == 0xa0 ) {	/* Version is optional */
  		tag = ber_skip_tag( ber, &len );
  		tag = ber_get_int( ber, &i );	/* Int: Version */
  	}
  	tag = ber_skip_tag( ber, &len );	/* Int: Serial (can be longer than ber_int_t) */
  	ber_skip_data( ber, len );
  	tag = ber_skip_tag( ber, &len );	/* Sequence: Signature */
  	ber_skip_data( ber, len );
  	if ( !get_subject ) {
  		tag = ber_peek_tag( ber, &len );	/* Sequence: Issuer DN */
  	} else {
  		tag = ber_skip_tag( ber, &len );
  		ber_skip_data( ber, len );
  		tag = ber_skip_tag( ber, &len );	/* Sequence: Validity */
  		ber_skip_data( ber, len );
  		tag = ber_peek_tag( ber, &len );	/* Sequence: Subject DN */
  	}
  	len = ber_ptrlen( ber );
  	dn->bv_val = cert->bv_val + len;
  	dn->bv_len = cert->bv_len - len;
  }
  
  static int
  tlsg_session_my_dn( tls_session *session, struct berval *der_dn )
  {
  	tlsg_session *s = (tlsg_session *)session;
  	const gnutls_datum_t *x;
  	struct berval bv;
  
  	x = gnutls_certificate_get_ours( s->session );
  
  	if (!x) return LDAP_INVALID_CREDENTIALS;
  	
  	bv.bv_val = (char *) x->data;
  	bv.bv_len = x->size;
  
  	tlsg_x509_cert_dn( &bv, der_dn, 1 );
  	return 0;
  }
  
  static int
  tlsg_session_peer_dn( tls_session *session, struct berval *der_dn )
  {
  	tlsg_session *s = (tlsg_session *)session;
  	if ( !s->peer_der_dn.bv_val ) {
  		const gnutls_datum_t *peer_cert_list;
  		unsigned int list_size;
  		struct berval bv;
  
  		peer_cert_list = gnutls_certificate_get_peers( s->session, 
  							&list_size );
  		if ( !peer_cert_list ) return LDAP_INVALID_CREDENTIALS;
  
  		bv.bv_len = peer_cert_list->size;
  		bv.bv_val = (char *) peer_cert_list->data;
  
  		tlsg_x509_cert_dn( &bv, &s->peer_der_dn, 1 );
  	}
  	*der_dn = s->peer_der_dn;
  	return 0;
  }
  
  /* what kind of hostname were we given? */
  #define	IS_DNS	0
  #define	IS_IP4	1
  #define	IS_IP6	2
  
  #define	CN_OID	"2.5.4.3"
  
  static int
  tlsg_session_chkhost( LDAP *ld, tls_session *session, const char *name_in )
  {
  	tlsg_session *s = (tlsg_session *)session;
  	int i, ret;
  	const gnutls_datum_t *peer_cert_list;
  	unsigned int list_size;
  	char altname[NI_MAXHOST];
  	size_t altnamesize;
  
  	gnutls_x509_crt_t cert;
  	const char *name;
  	char *ptr;
  	char *domain = NULL;
  #ifdef LDAP_PF_INET6
  	struct in6_addr addr;
  #else
  	struct in_addr addr;
  #endif
  	int len1 = 0, len2 = 0;
  	int ntype = IS_DNS;
  
  	if( ldap_int_hostname &&
  		( !name_in || !strcasecmp( name_in, "localhost" ) ) )
  	{
  		name = ldap_int_hostname;
  	} else {
  		name = name_in;
  	}
  
  	peer_cert_list = gnutls_certificate_get_peers( s->session, 
  						&list_size );
  	if ( !peer_cert_list ) {
  		Debug( LDAP_DEBUG_ANY,
  			"TLS: unable to get peer certificate.\n",
  			0, 0, 0 );
  		/* If this was a fatal condition, things would have
  		 * aborted long before now.
  		 */
  		return LDAP_SUCCESS;
  	}
  	ret = gnutls_x509_crt_init( &cert );
  	if ( ret < 0 )
  		return LDAP_LOCAL_ERROR;
  	ret = gnutls_x509_crt_import( cert, peer_cert_list, GNUTLS_X509_FMT_DER );
  	if ( ret ) {
  		gnutls_x509_crt_deinit( cert );
  		return LDAP_LOCAL_ERROR;
  	}
  
  #ifdef LDAP_PF_INET6
  	if (inet_pton(AF_INET6, name, &addr)) {
  		ntype = IS_IP6;
  	} else 
  #endif
  	if ((ptr = strrchr(name, '.')) && isdigit((unsigned char)ptr[1])) {
  		if (inet_aton(name, (struct in_addr *)&addr)) ntype = IS_IP4;
  	}
  	
  	if (ntype == IS_DNS) {
  		len1 = strlen(name);
  		domain = strchr(name, '.');
  		if (domain) {
  			len2 = len1 - (domain-name);
  		}
  	}
  
  	for ( i=0, ret=0; ret >= 0; i++ ) {
  		altnamesize = sizeof(altname);
  		ret = gnutls_x509_crt_get_subject_alt_name( cert, i, 
  			altname, &altnamesize, NULL );
  		if ( ret < 0 ) break;
  
  		/* ignore empty */
  		if ( altnamesize == 0 ) continue;
  
  		if ( ret == GNUTLS_SAN_DNSNAME ) {
  			if (ntype != IS_DNS) continue;
  	
  			/* Is this an exact match? */
  			if ((len1 == altnamesize) && !strncasecmp(name, altname, len1)) {
  				break;
  			}
  
  			/* Is this a wildcard match? */
  			if (domain && (altname[0] == '*') && (altname[1] == '.') &&
  				(len2 == altnamesize-1) && !strncasecmp(domain, &altname[1], len2))
  			{
  				break;
  			}
  		} else if ( ret == GNUTLS_SAN_IPADDRESS ) {
  			if (ntype == IS_DNS) continue;
  
  #ifdef LDAP_PF_INET6
  			if (ntype == IS_IP6 && altnamesize != sizeof(struct in6_addr)) {
  				continue;
  			} else
  #endif
  			if (ntype == IS_IP4 && altnamesize != sizeof(struct in_addr)) {
  				continue;
  			}
  			if (!memcmp(altname, &addr, altnamesize)) {
  				break;
  			}
  		}
  	}
  	if ( ret >= 0 ) {
  		ret = LDAP_SUCCESS;
  	} else {
  		/* find the last CN */
  		i=0;
  		do {
  			altnamesize = 0;
  			ret = gnutls_x509_crt_get_dn_by_oid( cert, CN_OID,
  				i, 1, altname, &altnamesize );
  			if ( ret == GNUTLS_E_SHORT_MEMORY_BUFFER )
  				i++;
  			else
  				break;
  		} while ( 1 );
  
  		if ( i ) {
  			altnamesize = sizeof(altname);
  			ret = gnutls_x509_crt_get_dn_by_oid( cert, CN_OID,
  				i-1, 0, altname, &altnamesize );
  		}
  
  		if ( ret < 0 ) {
  			Debug( LDAP_DEBUG_ANY,
  				"TLS: unable to get common name from peer certificate.\n",
  				0, 0, 0 );
  			ret = LDAP_CONNECT_ERROR;
  			if ( ld->ld_error ) {
  				LDAP_FREE( ld->ld_error );
  			}
  			ld->ld_error = LDAP_STRDUP(
  				_("TLS: unable to get CN from peer certificate"));
  
  		} else {
  			ret = LDAP_LOCAL_ERROR;
  			if ( !len1 ) len1 = strlen( name );
  			if ( len1 == altnamesize && strncasecmp(name, altname, altnamesize) == 0 ) {
  				ret = LDAP_SUCCESS;
  
  			} else if (( altname[0] == '*' ) && ( altname[1] == '.' )) {
  					/* Is this a wildcard match? */
  				if( domain &&
  					(len2 == altnamesize-1) && !strncasecmp(domain, &altname[1], len2)) {
  					ret = LDAP_SUCCESS;
  				}
  			}
  		}
  
  		if( ret == LDAP_LOCAL_ERROR ) {
  			altname[altnamesize] = '\0';
  			Debug( LDAP_DEBUG_ANY, "TLS: hostname (%s) does not match "
  				"common name in certificate (%s).\n", 
  				name, altname, 0 );
  			ret = LDAP_CONNECT_ERROR;
  			if ( ld->ld_error ) {
  				LDAP_FREE( ld->ld_error );
  			}
  			ld->ld_error = LDAP_STRDUP(
  				_("TLS: hostname does not match CN in peer certificate"));
  		}
  	}
  	gnutls_x509_crt_deinit( cert );
  	return ret;
  }
  
  static int
  tlsg_session_strength( tls_session *session )
  {
  	tlsg_session *s = (tlsg_session *)session;
  	gnutls_cipher_algorithm_t c;
  
  	c = gnutls_cipher_get( s->session );
  	return gnutls_cipher_get_key_size( c ) * 8;
  }
  
  /* suites is a string of colon-separated cipher suite names. */
  static int
  tlsg_parse_ciphers( tlsg_ctx *ctx, char *suites )
  {
  	const char *err;
  	int rc = gnutls_priority_init( &ctx->prios, suites, &err );
  	if ( rc )
  		ctx->prios = NULL;
  	return rc;
  }
  
  /*
   * TLS support for LBER Sockbufs
   */
  
  struct tls_data {
  	tlsg_session		*session;
  	Sockbuf_IO_Desc		*sbiod;
  };
  
  static ssize_t
  tlsg_recv( gnutls_transport_ptr_t ptr, void *buf, size_t len )
  {
  	struct tls_data		*p;
  
  	if ( buf == NULL || len <= 0 ) return 0;
  
  	p = (struct tls_data *)ptr;
  
  	if ( p == NULL || p->sbiod == NULL ) {
  		return 0;
  	}
  
  	return LBER_SBIOD_READ_NEXT( p->sbiod, buf, len );
  }
  
  static ssize_t
  tlsg_send( gnutls_transport_ptr_t ptr, const void *buf, size_t len )
  {
  	struct tls_data		*p;
  	
  	if ( buf == NULL || len <= 0 ) return 0;
  	
  	p = (struct tls_data *)ptr;
  
  	if ( p == NULL || p->sbiod == NULL ) {
  		return 0;
  	}
  
  	return LBER_SBIOD_WRITE_NEXT( p->sbiod, (char *)buf, len );
  }
  
  static int
  tlsg_sb_setup( Sockbuf_IO_Desc *sbiod, void *arg )
  {
  	struct tls_data		*p;
  	tlsg_session	*session = arg;
  
  	assert( sbiod != NULL );
  
  	p = LBER_MALLOC( sizeof( *p ) );
  	if ( p == NULL ) {
  		return -1;
  	}
  	
  	gnutls_transport_set_ptr( session->session, (gnutls_transport_ptr)p );
  	gnutls_transport_set_pull_function( session->session, tlsg_recv );
  	gnutls_transport_set_push_function( session->session, tlsg_send );
  	p->session = session;
  	p->sbiod = sbiod;
  	sbiod->sbiod_pvt = p;
  	return 0;
  }
  
  static int
  tlsg_sb_remove( Sockbuf_IO_Desc *sbiod )
  {
  	struct tls_data		*p;
  	
  	assert( sbiod != NULL );
  	assert( sbiod->sbiod_pvt != NULL );
  
  	p = (struct tls_data *)sbiod->sbiod_pvt;
  	gnutls_deinit ( p->session->session );
  	LBER_FREE( p->session );
  	LBER_FREE( sbiod->sbiod_pvt );
  	sbiod->sbiod_pvt = NULL;
  	return 0;
  }
  
  static int
  tlsg_sb_close( Sockbuf_IO_Desc *sbiod )
  {
  	struct tls_data		*p;
  	
  	assert( sbiod != NULL );
  	assert( sbiod->sbiod_pvt != NULL );
  
  	p = (struct tls_data *)sbiod->sbiod_pvt;
  	gnutls_bye ( p->session->session, GNUTLS_SHUT_WR );
  	return 0;
  }
  
  static int
  tlsg_sb_ctrl( Sockbuf_IO_Desc *sbiod, int opt, void *arg )
  {
  	struct tls_data		*p;
  	
  	assert( sbiod != NULL );
  	assert( sbiod->sbiod_pvt != NULL );
  
  	p = (struct tls_data *)sbiod->sbiod_pvt;
  	
  	if ( opt == LBER_SB_OPT_GET_SSL ) {
  		*((tlsg_session **)arg) = p->session;
  		return 1;
  		
  	} else if ( opt == LBER_SB_OPT_DATA_READY ) {
  		if( gnutls_record_check_pending( p->session->session ) > 0 ) {
  			return 1;
  		}
  	}
  	
  	return LBER_SBIOD_CTRL_NEXT( sbiod, opt, arg );
  }
  
  static ber_slen_t
  tlsg_sb_read( Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len)
  {
  	struct tls_data		*p;
  	ber_slen_t		ret;
  
  	assert( sbiod != NULL );
  	assert( SOCKBUF_VALID( sbiod->sbiod_sb ) );
  
  	p = (struct tls_data *)sbiod->sbiod_pvt;
  
  	ret = gnutls_record_recv ( p->session->session, buf, len );
  	switch (ret) {
  	case GNUTLS_E_INTERRUPTED:
  	case GNUTLS_E_AGAIN:
  		sbiod->sbiod_sb->sb_trans_needs_read = 1;
  		sock_errset(EWOULDBLOCK);
  		ret = 0;
  		break;
  	case GNUTLS_E_REHANDSHAKE:
  		for ( ret = gnutls_handshake ( p->session->session );
  		      ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN;
  		      ret = gnutls_handshake ( p->session->session ) );
  		sbiod->sbiod_sb->sb_trans_needs_read = 1;
  		ret = 0;
  		break;
  	default:
  		sbiod->sbiod_sb->sb_trans_needs_read = 0;
  	}
  	return ret;
  }
  
  static ber_slen_t
  tlsg_sb_write( Sockbuf_IO_Desc *sbiod, void *buf, ber_len_t len)
  {
  	struct tls_data		*p;
  	ber_slen_t		ret;
  
  	assert( sbiod != NULL );
  	assert( SOCKBUF_VALID( sbiod->sbiod_sb ) );
  
  	p = (struct tls_data *)sbiod->sbiod_pvt;
  
  	ret = gnutls_record_send ( p->session->session, (char *)buf, len );
  
  	if ( ret == GNUTLS_E_INTERRUPTED || ret == GNUTLS_E_AGAIN ) {
  		sbiod->sbiod_sb->sb_trans_needs_write = 1;
  		sock_errset(EWOULDBLOCK);
  		ret = 0;
  	} else {
  		sbiod->sbiod_sb->sb_trans_needs_write = 0;
  	}
  	return ret;
  }
  
  static Sockbuf_IO tlsg_sbio =
  {
  	tlsg_sb_setup,		/* sbi_setup */
  	tlsg_sb_remove,		/* sbi_remove */
  	tlsg_sb_ctrl,		/* sbi_ctrl */
  	tlsg_sb_read,		/* sbi_read */
  	tlsg_sb_write,		/* sbi_write */
  	tlsg_sb_close		/* sbi_close */
  };
  
  /* Certs are not automatically varified during the handshake */
  static int
  tlsg_cert_verify( tlsg_session *ssl )
  {
  	unsigned int status = 0;
  	int err;
  	time_t now = time(0);
  	time_t peertime;
  
  	err = gnutls_certificate_verify_peers2( ssl->session, &status );
  	if ( err < 0 ) {
  		Debug( LDAP_DEBUG_ANY,"TLS: gnutls_certificate_verify_peers2 failed %d\n",
  			err,0,0 );
  		return -1;
  	}
  	if ( status ) {
  		Debug( LDAP_DEBUG_TRACE,"TLS: peer cert untrusted or revoked (0x%x)\n",
  			status, 0,0 );
  		return -1;
  	}
  	peertime = gnutls_certificate_expiration_time_peers( ssl->session );
  	if ( peertime == (time_t) -1 ) {
  		Debug( LDAP_DEBUG_ANY, "TLS: gnutls_certificate_expiration_time_peers failed\n",
  			0, 0, 0 );
  		return -1;
  	}
  	if ( peertime < now ) {
  		Debug( LDAP_DEBUG_ANY, "TLS: peer certificate is expired\n",
  			0, 0, 0 );
  		return -1;
  	}
  	peertime = gnutls_certificate_activation_time_peers( ssl->session );
  	if ( peertime == (time_t) -1 ) {
  		Debug( LDAP_DEBUG_ANY, "TLS: gnutls_certificate_activation_time_peers failed\n",
  			0, 0, 0 );
  		return -1;
  	}
  	if ( peertime > now ) {
  		Debug( LDAP_DEBUG_ANY, "TLS: peer certificate not yet active\n",
  			0, 0, 0 );
  		return -1;
  	}
  	return 0;
  }
  
  tls_impl ldap_int_tls_impl = {
  	"GnuTLS",
  
  	tlsg_init,
  	tlsg_destroy,
  
  	tlsg_ctx_new,
  	tlsg_ctx_ref,
  	tlsg_ctx_free,
  	tlsg_ctx_init,
  
  	tlsg_session_new,
  	tlsg_session_connect,
  	tlsg_session_accept,
  	tlsg_session_upflags,
  	tlsg_session_errmsg,
  	tlsg_session_my_dn,
  	tlsg_session_peer_dn,
  	tlsg_session_chkhost,
  	tlsg_session_strength,
  
  	&tlsg_sbio,
  
  #ifdef LDAP_R_COMPILE
  	tlsg_thr_init,
  #else
  	NULL,
  #endif
  
  	0
  };
  
  #endif /* HAVE_GNUTLS */
  