/*
* Copyright (C) 2000-2012 Free Software Foundation, Inc.
*
* Author: Nikos Mavrogiannopoulos
*
* This file is part of GnuTLS.
*
* The GnuTLS is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>
*
*/
/* This file contains functions that manipulate a database backend for
* resumed sessions.
*/
#include "gnutls_int.h"
#include "errors.h"
#include <db.h>
#include <session_pack.h>
#include <datum.h>
#include "ext/server_name.h"
#include <intprops.h>
/**
* gnutls_db_set_retrieve_function:
* @session: is a #gnutls_session_t type.
* @retr_func: is the function.
*
* Sets the function that will be used to retrieve data from the
* resumed sessions database. This function must return a
* gnutls_datum_t containing the data on success, or a gnutls_datum_t
* containing null and 0 on failure.
*
* The datum's data must be allocated using the function
* gnutls_malloc().
*
* The first argument to @retr_func will be null unless
* gnutls_db_set_ptr() has been called.
**/
void
gnutls_db_set_retrieve_function(gnutls_session_t session,
gnutls_db_retr_func retr_func)
{
session->internals.db_retrieve_func = retr_func;
}
/**
* gnutls_db_set_remove_function:
* @session: is a #gnutls_session_t type.
* @rem_func: is the function.
*
* Sets the function that will be used to remove data from the
* resumed sessions database. This function must return 0 on success.
*
* The first argument to @rem_func will be null unless
* gnutls_db_set_ptr() has been called.
**/
void
gnutls_db_set_remove_function(gnutls_session_t session,
gnutls_db_remove_func rem_func)
{
session->internals.db_remove_func = rem_func;
}
/**
* gnutls_db_set_store_function:
* @session: is a #gnutls_session_t type.
* @store_func: is the function
*
* Sets the function that will be used to store data in the resumed
* sessions database. This function must return 0 on success.
*
* The first argument to @store_func will be null unless
* gnutls_db_set_ptr() has been called.
**/
void
gnutls_db_set_store_function(gnutls_session_t session,
gnutls_db_store_func store_func)
{
session->internals.db_store_func = store_func;
}
/**
* gnutls_db_set_ptr:
* @session: is a #gnutls_session_t type.
* @ptr: is the pointer
*
* Sets the pointer that will be provided to db store, retrieve and
* delete functions, as the first argument.
**/
void gnutls_db_set_ptr(gnutls_session_t session, void *ptr)
{
session->internals.db_ptr = ptr;
}
/**
* gnutls_db_get_ptr:
* @session: is a #gnutls_session_t type.
*
* Get db function pointer.
*
* Returns: the pointer that will be sent to db store, retrieve and
* delete functions, as the first argument.
**/
void *gnutls_db_get_ptr(gnutls_session_t session)
{
return session->internals.db_ptr;
}
/**
* gnutls_db_set_cache_expiration:
* @session: is a #gnutls_session_t type.
* @seconds: is the number of seconds.
*
* Set the expiration time for resumed sessions. The default is 21600
* (6 hours) at the time of writing.
*
* The maximum value that can be set using this function is 604800
* (7 days).
*
**/
void gnutls_db_set_cache_expiration(gnutls_session_t session, int seconds)
{
session->internals.expire_time = seconds;
if (session->internals.expire_time > 604800)
session->internals.expire_time = 604800;
}
/**
* gnutls_db_get_default_cache_expiration:
*
* Returns the expiration time (in seconds) of stored sessions for resumption.
**/
unsigned gnutls_db_get_default_cache_expiration(void)
{
return DEFAULT_EXPIRE_TIME;
}
/**
* gnutls_db_check_entry:
* @session: is a #gnutls_session_t type.
* @session_entry: is the session data (not key)
*
* This function has no effect.
*
* Returns: Returns %GNUTLS_E_EXPIRED, if the database entry has
* expired or 0 otherwise.
*
* Deprecated: This function is deprecated.
**/
int
gnutls_db_check_entry(gnutls_session_t session,
gnutls_datum_t session_entry)
{
return 0;
}
/**
* gnutls_db_check_entry_time:
* @entry: is a pointer to a #gnutls_datum_t type.
*
* This function returns the time that this entry was active.
* It can be used for database entry expiration.
*
* Returns: The time this entry was created, or zero on error.
**/
time_t gnutls_db_check_entry_time(gnutls_datum_t * entry)
{
uint32_t t;
uint32_t magic;
if (entry->size < 8)
return gnutls_assert_val(0);
magic = _gnutls_read_uint32(entry->data);
if (magic != PACKED_SESSION_MAGIC)
return gnutls_assert_val(0);
t = _gnutls_read_uint32(&entry->data[4]);
return t;
}
/**
* gnutls_db_check_entry_expire_time:
* @entry: is a pointer to a #gnutls_datum_t type.
*
* This function returns the time that this entry will expire.
* It can be used for database entry expiration.
*
* Returns: The time this entry will expire, or zero on error.
*
* Since: 3.6.5
**/
time_t gnutls_db_check_entry_expire_time(gnutls_datum_t *entry)
{
uint32_t t;
uint32_t e;
uint32_t magic;
if (entry->size < 12)
return gnutls_assert_val(0);
magic = _gnutls_read_uint32(entry->data);
if (magic != PACKED_SESSION_MAGIC)
return gnutls_assert_val(0);
t = _gnutls_read_uint32(&entry->data[4]);
e = _gnutls_read_uint32(&entry->data[8]);
if (INT_ADD_OVERFLOW(t, e))
return gnutls_assert_val(0);
return t + e;
}
/* Checks if both db_store and db_retrieve functions have
* been set up.
*/
static int db_func_is_ok(gnutls_session_t session)
{
if (session->internals.db_store_func != NULL &&
session->internals.db_retrieve_func != NULL)
return 0;
else
return GNUTLS_E_DB_ERROR;
}
/* Stores session data to the db backend.
*/
static int
store_session(gnutls_session_t session,
gnutls_datum_t session_id, gnutls_datum_t session_data)
{
int ret = 0;
if (db_func_is_ok(session) != 0) {
return GNUTLS_E_DB_ERROR;
}
if (session_data.data == NULL || session_data.size == 0) {
gnutls_assert();
return GNUTLS_E_INVALID_SESSION;
}
/* if we can't read why bother writing? */
ret = session->internals.db_store_func(session->internals.db_ptr,
session_id, session_data);
return (ret == 0 ? ret : GNUTLS_E_DB_ERROR);
}
int _gnutls_server_register_current_session(gnutls_session_t session)
{
gnutls_datum_t key;
gnutls_datum_t content;
int ret = 0;
key.data = session->security_parameters.session_id;
key.size = session->security_parameters.session_id_size;
if (session->internals.resumable == RESUME_FALSE) {
gnutls_assert();
return GNUTLS_E_INVALID_SESSION;
}
if (session->security_parameters.session_id_size == 0) {
gnutls_assert();
return GNUTLS_E_INVALID_SESSION;
}
ret = _gnutls_session_pack(session, &content);
if (ret < 0) {
gnutls_assert();
return ret;
}
ret = store_session(session, key, content);
_gnutls_free_datum(&content);
return ret;
}
int _gnutls_check_resumed_params(gnutls_session_t session)
{
time_t timestamp = gnutls_time(0);
const version_entry_st *vers;
/* check whether the session is expired */
if (timestamp -
session->internals.resumed_security_parameters.timestamp >
session->internals.expire_time
|| session->internals.resumed_security_parameters.timestamp >
timestamp)
return gnutls_assert_val(GNUTLS_E_EXPIRED);
/* check various parameters applicable to resumption in TLS1.2 or earlier
*/
vers = get_version(session);
if (!vers || !vers->tls13_sem) {
if (session->internals.resumed_security_parameters.ext_master_secret !=
session->security_parameters.ext_master_secret)
return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
if (!_gnutls_server_name_matches_resumed(session))
return gnutls_assert_val(GNUTLS_E_INVALID_SESSION);
}
return 0;
}
int
_gnutls_server_restore_session(gnutls_session_t session,
uint8_t * session_id, int session_id_size)
{
gnutls_datum_t data;
gnutls_datum_t key;
int ret;
if (session_id == NULL || session_id_size == 0) {
gnutls_assert();
return GNUTLS_E_INVALID_REQUEST;
}
if (session->internals.premaster_set != 0) { /* hack for CISCO's DTLS-0.9 */
if (session_id_size ==
session->internals.resumed_security_parameters.
session_id_size
&& memcmp(session_id,
session->internals.
resumed_security_parameters.session_id,
session_id_size) == 0)
return 0;
}
key.data = session_id;
key.size = session_id_size;
if (db_func_is_ok(session) != 0) {
gnutls_assert();
return GNUTLS_E_INVALID_SESSION;
}
data =
session->internals.db_retrieve_func(session->internals.db_ptr,
key);
if (data.data == NULL) {
gnutls_assert();
return GNUTLS_E_INVALID_SESSION;
}
ret = gnutls_session_set_data(session, data.data, data.size);
gnutls_free(data.data);
if (ret < 0) {
gnutls_assert();
return ret;
}
/* expiration check is performed inside */
ret = _gnutls_check_resumed_params(session);
if (ret < 0)
return gnutls_assert_val(ret);
return 0;
}
/**
* gnutls_db_remove_session:
* @session: is a #gnutls_session_t type.
*
* This function will remove the current session data from the
* session database. This will prevent future handshakes reusing
* these session data. This function should be called if a session
* was terminated abnormally, and before gnutls_deinit() is called.
*
* Normally gnutls_deinit() will remove abnormally terminated
* sessions.
**/
void gnutls_db_remove_session(gnutls_session_t session)
{
gnutls_datum_t session_id;
int ret = 0;
session_id.data = session->security_parameters.session_id;
session_id.size = session->security_parameters.session_id_size;
if (session->internals.db_remove_func == NULL) {
gnutls_assert();
return /* GNUTLS_E_DB_ERROR */ ;
}
if (session_id.data == NULL || session_id.size == 0) {
gnutls_assert();
return /* GNUTLS_E_INVALID_SESSION */ ;
}
/* if we can't read why bother writing? */
ret = session->internals.db_remove_func(session->internals.db_ptr,
session_id);
if (ret != 0)
gnutls_assert();
}