ssl_ticket.h

00001 /**
00002  * \file ssl_ticket.h
00003  *
00004  * \brief TLS server ticket callbacks implementation
00005  */
00006 /*
00007  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00008  *  SPDX-License-Identifier: Apache-2.0
00009  *
00010  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00011  *  not use this file except in compliance with the License.
00012  *  You may obtain a copy of the License at
00013  *
00014  *  http://www.apache.org/licenses/LICENSE-2.0
00015  *
00016  *  Unless required by applicable law or agreed to in writing, software
00017  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00018  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00019  *  See the License for the specific language governing permissions and
00020  *  limitations under the License.
00021  *
00022  *  This file is part of mbed TLS (https://tls.mbed.org)
00023  */
00024 #ifndef MBEDTLS_SSL_TICKET_H
00025 #define MBEDTLS_SSL_TICKET_H
00026 
00027 /*
00028  * This implementation of the session ticket callbacks includes key
00029  * management, rotating the keys periodically in order to preserve forward
00030  * secrecy, when MBEDTLS_HAVE_TIME is defined.
00031  */
00032 
00033 #include "ssl.h"
00034 #include "cipher.h"
00035 
00036 #if defined(MBEDTLS_THREADING_C)
00037 #include "threading.h"
00038 #endif
00039 
00040 #ifdef __cplusplus
00041 extern "C" {
00042 #endif
00043 
00044 /**
00045  * \brief   Information for session ticket protection
00046  */
00047 typedef struct
00048 {
00049     unsigned char name[4];          /*!< random key identifier              */
00050     uint32_t generation_time ;       /*!< key generation timestamp (seconds) */
00051     mbedtls_cipher_context_t ctx ;   /*!< context for auth enc/decryption    */
00052 }
00053 mbedtls_ssl_ticket_key;
00054 
00055 /**
00056  * \brief   Context for session ticket handling functions
00057  */
00058 typedef struct
00059 {
00060     mbedtls_ssl_ticket_key keys[2]; /*!< ticket protection keys             */
00061     unsigned char active ;           /*!< index of the currently active key  */
00062 
00063     uint32_t ticket_lifetime ;       /*!< lifetime of tickets in seconds     */
00064 
00065     /** Callback for getting (pseudo-)random numbers                        */
00066     int  (*f_rng)(void *, unsigned char *, size_t);
00067     void *p_rng ;                    /*!< context for the RNG function       */
00068 
00069 #if defined(MBEDTLS_THREADING_C)
00070     mbedtls_threading_mutex_t mutex;
00071 #endif
00072 }
00073 mbedtls_ssl_ticket_context;
00074 
00075 /**
00076  * \brief           Initialize a ticket context.
00077  *                  (Just make it ready for mbedtls_ssl_ticket_setup()
00078  *                  or mbedtls_ssl_ticket_free().)
00079  *
00080  * \param ctx       Context to be initialized
00081  */
00082 void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx );
00083 
00084 /**
00085  * \brief           Prepare context to be actually used
00086  *
00087  * \param ctx       Context to be set up
00088  * \param f_rng     RNG callback function
00089  * \param p_rng     RNG callback context
00090  * \param cipher    AEAD cipher to use for ticket protection.
00091  *                  Recommended value: MBEDTLS_CIPHER_AES_256_GCM.
00092  * \param lifetime  Tickets lifetime in seconds
00093  *                  Recommended value: 86400 (one day).
00094  *
00095  * \note            It is highly recommended to select a cipher that is at
00096  *                  least as strong as the the strongest ciphersuite
00097  *                  supported. Usually that means a 256-bit key.
00098  *
00099  * \note            The lifetime of the keys is twice the lifetime of tickets.
00100  *                  It is recommended to pick a reasonnable lifetime so as not
00101  *                  to negate the benefits of forward secrecy.
00102  *
00103  * \return          0 if successful,
00104  *                  or a specific MBEDTLS_ERR_XXX error code
00105  */
00106 int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx,
00107     int (*f_rng)(void *, unsigned char *, size_t), void *p_rng,
00108     mbedtls_cipher_type_t cipher,
00109     uint32_t lifetime );
00110 
00111 /**
00112  * \brief           Implementation of the ticket write callback
00113  *
00114  * \note            See \c mbedlts_ssl_ticket_write_t for description
00115  */
00116 mbedtls_ssl_ticket_write_t mbedtls_ssl_ticket_write;
00117 
00118 /**
00119  * \brief           Implementation of the ticket parse callback
00120  *
00121  * \note            See \c mbedlts_ssl_ticket_parse_t for description
00122  */
00123 mbedtls_ssl_ticket_parse_t mbedtls_ssl_ticket_parse;
00124 
00125 /**
00126  * \brief           Free a context's content and zeroize it.
00127  *
00128  * \param ctx       Context to be cleaned up
00129  */
00130 void mbedtls_ssl_ticket_free( mbedtls_ssl_ticket_context *ctx );
00131 
00132 #ifdef __cplusplus
00133 }
00134 #endif
00135 
00136 #endif /* ssl_ticket.h */