1 /** 2 * \file ssl_ticket.h 3 * 4 * \brief TLS server ticket callbacks implementation 5 */ 6 /* 7 * Copyright (C) 2006-2015, ARM Limited, All Rights Reserved 8 * SPDX-License-Identifier: Apache-2.0 9 * 10 * Licensed under the Apache License, Version 2.0 (the "License"); you may 11 * not use this file except in compliance with the License. 12 * You may obtain a copy of the License at 13 * 14 * http://www.apache.org/licenses/LICENSE-2.0 15 * 16 * Unless required by applicable law or agreed to in writing, software 17 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 18 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 19 * See the License for the specific language governing permissions and 20 * limitations under the License. 21 * 22 * This file is part of mbed TLS (https://tls.mbed.org) 23 */ 24 #ifndef MBEDTLS_SSL_TICKET_H 25 #define MBEDTLS_SSL_TICKET_H 26 27 /* 28 * This implementation of the session ticket callbacks includes key 29 * management, rotating the keys periodically in order to preserve forward 30 * secrecy, when MBEDTLS_HAVE_TIME is defined. 31 */ 32 33 #include "ssl.h" 34 #include "cipher.h" 35 36 #if defined(MBEDTLS_THREADING_C) 37 #include "threading.h" 38 #endif 39 40 #ifdef __cplusplus 41 extern "C" { 42 #endif 43 44 /** 45 * \brief Information for session ticket protection 46 */ 47 typedef struct mbedtls_ssl_ticket_key 48 { 49 unsigned char name[4]; /*!< random key identifier */ 50 uint32_t generation_time; /*!< key generation timestamp (seconds) */ 51 mbedtls_cipher_context_t ctx; /*!< context for auth enc/decryption */ 52 } 53 mbedtls_ssl_ticket_key; 54 55 /** 56 * \brief Context for session ticket handling functions 57 */ 58 typedef struct mbedtls_ssl_ticket_context 59 { 60 mbedtls_ssl_ticket_key keys[2]; /*!< ticket protection keys */ 61 unsigned char active; /*!< index of the currently active key */ 62 63 uint32_t ticket_lifetime; /*!< lifetime of tickets in seconds */ 64 65 /** Callback for getting (pseudo-)random numbers */ 66 int (*f_rng)(void *, unsigned char *, size_t); 67 void *p_rng; /*!< context for the RNG function */ 68 69 #if defined(MBEDTLS_THREADING_C) 70 mbedtls_threading_mutex_t mutex; 71 #endif 72 } 73 mbedtls_ssl_ticket_context; 74 75 /** 76 * \brief Initialize a ticket context. 77 * (Just make it ready for mbedtls_ssl_ticket_setup() 78 * or mbedtls_ssl_ticket_free().) 79 * 80 * \param ctx Context to be initialized 81 */ 82 void mbedtls_ssl_ticket_init( mbedtls_ssl_ticket_context *ctx ); 83 84 /** 85 * \brief Prepare context to be actually used 86 * 87 * \param ctx Context to be set up 88 * \param f_rng RNG callback function 89 * \param p_rng RNG callback context 90 * \param cipher AEAD cipher to use for ticket protection. 91 * Recommended value: MBEDTLS_CIPHER_AES_256_GCM. 92 * \param lifetime Tickets lifetime in seconds 93 * Recommended value: 86400 (one day). 94 * 95 * \note It is highly recommended to select a cipher that is at 96 * least as strong as the the strongest ciphersuite 97 * supported. Usually that means a 256-bit key. 98 * 99 * \note The lifetime of the keys is twice the lifetime of tickets. 100 * It is recommended to pick a reasonnable lifetime so as not 101 * to negate the benefits of forward secrecy. 102 * 103 * \return 0 if successful, 104 * or a specific MBEDTLS_ERR_XXX error code 105 */ 106 int mbedtls_ssl_ticket_setup( mbedtls_ssl_ticket_context *ctx, 107 int (*f_rng)(void *, unsigned char *, size_t), void *p_rng, 108 mbedtls_cipher_type_t cipher, 109 uint32_t lifetime ); 110 111 /** 112 * \brief Implementation of the ticket write callback 113 * 114 * \note See \c mbedlts_ssl_ticket_write_t for description 115 */ 116 mbedtls_ssl_ticket_write_t mbedtls_ssl_ticket_write; 117 118 /** 119 * \brief Implementation of the ticket parse callback 120 * 121 * \note See \c mbedlts_ssl_ticket_parse_t for description 122 */ 123 mbedtls_ssl_ticket_parse_t mbedtls_ssl_ticket_parse; 124 125 /** 126 * \brief Free a context's content and zeroize it. 127 * 128 * \param ctx Context to be cleaned up 129 */ 130 void mbedtls_ssl_ticket_free( mbedtls_ssl_ticket_context *ctx ); 131 132 #ifdef __cplusplus 133 } 134 #endif 135 136 #endif /* ssl_ticket.h */ 137