_ Git - BearSSL/blob - inc/bearssl.h

   1 /*
   2  * Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining
   5  * a copy of this software and associated documentation files (the
   6  * "Software"), to deal in the Software without restriction, including
   7  * without limitation the rights to use, copy, modify, merge, publish,
   8  * distribute, sublicense, and/or sell copies of the Software, and to
   9  * permit persons to whom the Software is furnished to do so, subject to
  10  * the following conditions:
  11  *
  12  * The above copyright notice and this permission notice shall be
  13  * included in all copies or substantial portions of the Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  16  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  17  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  18  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  19  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  20  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  21  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  22  * SOFTWARE.
  23  */
  24
  25 #ifndef BR_BEARSSL_H__
  26 #define BR_BEARSSL_H__
  27
  28 #include <stddef.h>
  29 #include <stdint.h>
  30
  31 /** \mainpage BearSSL API
  32  *
  33  * # API Layout
  34  *
  35  * The functions and structures defined by the BearSSL API are located
  36  * in various header files:
  37  *
  38  * | Header file     | Elements                                          |
  39  * | :-------------- | :------------------------------------------------ |
  40  * | bearssl_hash.h  | Hash functions                                    |
  41  * | bearssl_hmac.h  | HMAC                                              |
  42  * | bearssl_kdf.h   | Key Derivation Functions                          |
  43  * | bearssl_rand.h  | Pseudorandom byte generators                      |
  44  * | bearssl_prf.h   | PRF implementations (for SSL/TLS)                 |
  45  * | bearssl_block.h | Symmetric encryption                              |
  46  * | bearssl_aead.h  | AEAD algorithms (combined encryption + MAC)       |
  47  * | bearssl_rsa.h   | RSA encryption and signatures                     |
  48  * | bearssl_ec.h    | Elliptic curves support (including ECDSA)         |
  49  * | bearssl_ssl.h   | SSL/TLS engine interface                          |
  50  * | bearssl_x509.h  | X.509 certificate decoding and validation         |
  51  * | bearssl_pem.h   | Base64/PEM decoding support functions             |
  52  *
  53  * Applications using BearSSL are supposed to simply include `bearssl.h`
  54  * as follows:
  55  *
  56  *     #include <bearssl.h>
  57  *
  58  * The `bearssl.h` file itself includes all the other header files. It is
  59  * possible to include specific header files, but it has no practical
  60  * advantage for the application. The API is separated into separate
  61  * header files only for documentation convenience.
  62  *
  63  *
  64  * # Conventions
  65  *
  66  * ## MUST and SHALL
  67  *
  68  * In all descriptions, the usual "MUST", "SHALL", "MAY",... terminology
  69  * is used. Failure to meet requirements expressed with a "MUST" or
  70  * "SHALL" implies undefined behaviour, which means that segmentation
  71  * faults, buffer overflows, and other similar adverse events, may occur.
  72  *
  73  * In general, BearSSL is not very forgiving of programming errors, and
  74  * does not include much failsafes or error reporting when the problem
  75  * does not arise from external transient conditions, and can be fixed
  76  * only in the application code. This is done so in order to make the
  77  * total code footprint lighter.
  78  *
  79  *
  80  * ## `NULL` values
  81  *
  82  * Function parameters with a pointer type shall not be `NULL` unless
  83  * explicitly authorised by the documentation. As an exception, when
  84  * the pointer aims at a sequence of bytes and is accompanied with
  85  * a length parameter, and the length is zero (meaning that there is
  86  * no byte at all to retrieve), then the pointer may be `NULL` even if
  87  * not explicitly allowed.
  88  *
  89  *
  90  * ## Memory Allocation
  91  *
  92  * BearSSL does not perform dynamic memory allocation. This implies that
  93  * for any functionality that requires a non-transient state, the caller
  94  * is responsible for allocating the relevant context structure. Such
  95  * allocation can be done in any appropriate area, including static data
  96  * segments, the heap, and the stack, provided that proper alignment is
  97  * respected. The header files define these context structures
  98  * (including size and contents), so the C compiler should handle
  99  * alignment automatically.
 100  *
 101  * Since there is no dynamic resource allocation, there is also nothing to
 102  * release. When the calling code is done with a BearSSL feature, it
 103  * may simple release the context structures it allocated itself, with
 104  * no "close function" to call. If the context structures were allocated
 105  * on the stack (as local variables), then even that release operation is
 106  * implicit.
 107  *
 108  *
 109  * ## Structure Contents
 110  *
 111  * Except when explicitly indicated, structure contents are opaque: they
 112  * are included in the header files so that calling code may know the
 113  * structure sizes and alignment requirements, but callers SHALL NOT
 114  * access individual fields directly. For fields that are supposed to
 115  * be read from or written to, the API defines accessor functions (the
 116  * simplest of these accessor functions are defined as `static inline`
 117  * functions, and the C compiler will optimise them away).
 118  *
 119  *
 120  * # API Usage
 121  *
 122  * BearSSL usage for running a SSL/TLS client or server is described
 123  * on the [BearSSL Web site](https://www.bearssl.org/api1.html). The
 124  * BearSSL source archive also comes with sample code.
 125  */
 126
 127 #include "bearssl_hash.h"
 128 #include "bearssl_hmac.h"
 129 #include "bearssl_kdf.h"
 130 #include "bearssl_rand.h"
 131 #include "bearssl_prf.h"
 132 #include "bearssl_block.h"
 133 #include "bearssl_aead.h"
 134 #include "bearssl_rsa.h"
 135 #include "bearssl_ec.h"
 136 #include "bearssl_ssl.h"
 137 #include "bearssl_x509.h"
 138 #include "bearssl_pem.h"
 139
 140 /** \brief Type for a configuration option.
 141  *
 142  * A "configuration option" is a value that is selected when the BearSSL
 143  * library itself is compiled. Most options are boolean; their value is
 144  * then either 1 (option is enabled) or 0 (option is disabled). Some
 145  * values have other integer values. Option names correspond to macro
 146  * names. Some of the options can be explicitly set in the internal
 147  * `"config.h"` file.
 148  */
 149 typedef struct {
 150         /** \brief Configurable option name. */
 151         const char *name;
 152         /** \brief Configurable option value. */
 153         long value;
 154 } br_config_option;
 155
 156 /** \brief Get configuration report.
 157  *
 158  * This function returns compiled configuration options, each as a
 159  * 'long' value. Names match internal macro names, in particular those
 160  * that can be set in the `"config.h"` inner file. For boolean options,
 161  * the numerical value is 1 if enabled, 0 if disabled. For maximum
 162  * key sizes, values are expressed in bits.
 163  *
 164  * The returned array is terminated by an entry whose `name` is `NULL`.
 165  *
 166  * \return  the configuration report.
 167  */
 168 const br_config_option *br_get_config(void);
 169
 170 #endif