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/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef BR_BEARSSL_SSL_H__
#define BR_BEARSSL_SSL_H__
#include <stddef.h>
#include <stdint.h>
#include "bearssl_block.h"
#include "bearssl_hash.h"
#include "bearssl_hmac.h"
#include "bearssl_prf.h"
#include "bearssl_rand.h"
#include "bearssl_x509.h"
#ifdef __cplusplus
extern "C" {
#endif
/** \file bearssl_ssl.h
*
* # SSL
*
* For an overview of the SSL/TLS API, see [the BearSSL Web
* site](https://www.bearssl.org/api1.html).
*
* The `BR_TLS_*` constants correspond to the standard cipher suites and
* their values in the [IANA
* registry](http://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-4).
*
* The `BR_ALERT_*` constants are for standard TLS alert messages. When
* a fatal alert message is sent of received, then the SSL engine context
* status is set to the sum of that alert value (an integer in the 0..255
* range) and a fixed offset (`BR_ERR_SEND_FATAL_ALERT` for a sent alert,
* `BR_ERR_RECV_FATAL_ALERT` for a received alert).
*/
/** \brief Optimal input buffer size. */
#define BR_SSL_BUFSIZE_INPUT (16384 + 325)
/** \brief Optimal output buffer size. */
#define BR_SSL_BUFSIZE_OUTPUT (16384 + 85)
/** \brief Optimal buffer size for monodirectional engine
(shared input/output buffer). */
#define BR_SSL_BUFSIZE_MONO BR_SSL_BUFSIZE_INPUT
/** \brief Optimal buffer size for bidirectional engine
(single buffer split into two separate input/output buffers). */
#define BR_SSL_BUFSIZE_BIDI (BR_SSL_BUFSIZE_INPUT + BR_SSL_BUFSIZE_OUTPUT)
/*
* Constants for known SSL/TLS protocol versions (SSL 3.0, TLS 1.0, TLS 1.1
* and TLS 1.2). Note that though there is a constant for SSL 3.0, that
* protocol version is not actually supported.
*/
/** \brief Protocol version: SSL 3.0 (unsupported). */
#define BR_SSL30 0x0300
/** \brief Protocol version: TLS 1.0. */
#define BR_TLS10 0x0301
/** \brief Protocol version: TLS 1.1. */
#define BR_TLS11 0x0302
/** \brief Protocol version: TLS 1.2. */
#define BR_TLS12 0x0303
/*
* Error constants. They are used to report the reason why a context has
* been marked as failed.
*
* Implementation note: SSL-level error codes should be in the 1..31
* range. The 32..63 range is for certificate decoding and validation
* errors. Received fatal alerts imply an error code in the 256..511 range.
*/
/** \brief SSL status: no error so far (0). */
#define BR_ERR_OK 0
/** \brief SSL status: caller-provided parameter is incorrect. */
#define BR_ERR_BAD_PARAM 1
/** \brief SSL status: operation requested by the caller cannot be applied
with the current context state (e.g. reading data while outgoing data
is waiting to be sent). */
#define BR_ERR_BAD_STATE 2
/** \brief SSL status: incoming protocol or record version is unsupported. */
#define BR_ERR_UNSUPPORTED_VERSION 3
/** \brief SSL status: incoming record version does not match the expected
version. */
#define BR_ERR_BAD_VERSION 4
/** \brief SSL status: incoming record length is invalid. */
#define BR_ERR_BAD_LENGTH 5
/** \brief SSL status: incoming record is too large to be processed, or
buffer is too small for the handshake message to send. */
#define BR_ERR_TOO_LARGE 6
/** \brief SSL status: decryption found an invalid padding, or the record
MAC is not correct. */
#define BR_ERR_BAD_MAC 7
/** \brief SSL status: no initial entropy was provided, and none can be
obtained from the OS. */
#define BR_ERR_NO_RANDOM 8
/** \brief SSL status: incoming record type is unknown. */
#define BR_ERR_UNKNOWN_TYPE 9
/** \brief SSL status: incoming record or message has wrong type with
regards to the current engine state. */
#define BR_ERR_UNEXPECTED 10
/** \brief SSL status: ChangeCipherSpec message from the peer has invalid
contents. */
#define BR_ERR_BAD_CCS 12
/** \brief SSL status: alert message from the peer has invalid contents
(odd length). */
#define BR_ERR_BAD_ALERT 13
/** \brief SSL status: incoming handshake message decoding failed. */
#define BR_ERR_BAD_HANDSHAKE 14
/** \brief SSL status: ServerHello contains a session ID which is larger
than 32 bytes. */
#define BR_ERR_OVERSIZED_ID 15
/** \brief SSL status: server wants to use a cipher suite that we did
not claim to support. This is also reported if we tried to advertise
a cipher suite that we do not support. */
#define BR_ERR_BAD_CIPHER_SUITE 16
/** \brief SSL status: server wants to use a compression that we did not
claim to support. */
#define BR_ERR_BAD_COMPRESSION 17
/** \brief SSL status: server's max fragment length does not match
client's. */
#define BR_ERR_BAD_FRAGLEN 18
/** \brief SSL status: secure renegotiation failed. */
#define BR_ERR_BAD_SECRENEG 19
/** \brief SSL status: server sent an extension type that we did not
announce, or used the same extension type several times in a single
ServerHello. */
#define BR_ERR_EXTRA_EXTENSION 20
/** \brief SSL status: invalid Server Name Indication contents (when
used by the server, this extension shall be empty). */
#define BR_ERR_BAD_SNI 21
/** \brief SSL status: invalid ServerHelloDone from the server (length
is not 0). */
#define BR_ERR_BAD_HELLO_DONE 22
/** \brief SSL status: internal limit exceeded (e.g. server's public key
is too large). */
#define BR_ERR_LIMIT_EXCEEDED 23
/** \brief SSL status: Finished message from peer does not match the
expected value. */
#define BR_ERR_BAD_FINISHED 24
/** \brief SSL status: session resumption attempt with distinct version
or cipher suite. */
#define BR_ERR_RESUME_MISMATCH 25
/** \brief SSL status: unsupported or invalid algorithm (ECDHE curve,
signature algorithm, hash function). */
#define BR_ERR_INVALID_ALGORITHM 26
/** \brief SSL status: invalid signature (on ServerKeyExchange from
server, or in CertificateVerify from client). */
#define BR_ERR_BAD_SIGNATURE 27
/** \brief SSL status: peer's public key does not have the proper type
or is not allowed for requested operation. */
#define BR_ERR_WRONG_KEY_USAGE 28
/** \brief SSL status: client did not send a certificate upon request,
or the client certificate could not be validated. */
#define BR_ERR_NO_CLIENT_AUTH 29
/** \brief SSL status: I/O error or premature close on underlying
transport stream. This error code is set only by the simplified
I/O API ("br_sslio_*"). */
#define BR_ERR_IO 31
/** \brief SSL status: base value for a received fatal alert.
When a fatal alert is received from the peer, the alert value
is added to this constant. */
#define BR_ERR_RECV_FATAL_ALERT 256
/** \brief SSL status: base value for a sent fatal alert.
When a fatal alert is sent to the peer, the alert value is added
to this constant. */
#define BR_ERR_SEND_FATAL_ALERT 512
/* ===================================================================== */
/**
* \brief Decryption engine for SSL.
*
* When processing incoming records, the SSL engine will use a decryption
* engine that uses a specific context structure, and has a set of
* methods (a vtable) that follows this template.
*
* The decryption engine is responsible for applying decryption, verifying
* MAC, and keeping track of the record sequence number.
*/
typedef struct br_sslrec_in_class_ br_sslrec_in_class;
struct br_sslrec_in_class_ {
/**
* \brief Context size (in bytes).
*/
size_t context_size;
/**
* \brief Test validity of the incoming record length.
*
* This function returns 1 if the announced length for an
* incoming record is valid, 0 otherwise,
*
* \param ctx decryption engine context.
* \param record_len incoming record length.
* \return 1 of a valid length, 0 otherwise.
*/
int (*check_length)(const br_sslrec_in_class *const *ctx,
size_t record_len);
/**
* \brief Decrypt the incoming record.
*
* This function may assume that the record length is valid
* (it has been previously tested with `check_length()`).
* Decryption is done in place; `*len` is updated with the
* cleartext length, and the address of the first plaintext
* byte is returned. If the record is correct but empty, then
* `*len` is set to 0 and a non-`NULL` pointer is returned.
*
* On decryption/MAC error, `NULL` is returned.
*
* \param ctx decryption engine context.
* \param record_type record type (23 for application data, etc).
* \param version record version.
* \param payload address of encrypted payload.
* \param len pointer to payload length (updated).
* \return pointer to plaintext, or `NULL` on error.
*/
unsigned char *(*decrypt)(const br_sslrec_in_class **ctx,
int record_type, unsigned version,
void *payload, size_t *len);
};
/**
* \brief Encryption engine for SSL.
*
* When building outgoing records, the SSL engine will use an encryption
* engine that uses a specific context structure, and has a set of
* methods (a vtable) that follows this template.
*
* The encryption engine is responsible for applying encryption and MAC,
* and keeping track of the record sequence number.
*/
typedef struct br_sslrec_out_class_ br_sslrec_out_class;
struct br_sslrec_out_class_ {
/**
* \brief Context size (in bytes).
*/
size_t context_size;
/**
* \brief Compute maximum plaintext sizes and offsets.
*
* When this function is called, the `*start` and `*end`
* values contain offsets designating the free area in the
* outgoing buffer for plaintext data; that free area is
* preceded by a 5-byte space which will receive the record
* header.
*
* The `max_plaintext()` function is responsible for adjusting
* both `*start` and `*end` to make room for any record-specific
* header, MAC, padding, and possible split.
*
* \param ctx encryption engine context.
* \param start pointer to start of plaintext offset (updated).
* \param end pointer to start of plaintext offset (updated).
*/
void (*max_plaintext)(const br_sslrec_out_class *const *ctx,
size_t *start, size_t *end);
/**
* \brief Perform record encryption.
*
* This function encrypts the record. The plaintext address and
* length are provided. Returned value is the start of the
* encrypted record (or sequence of records, if a split was
* performed), _including_ the 5-byte header, and `*len` is
* adjusted to the total size of the record(s), there again
* including the header(s).
*
* \param ctx decryption engine context.
* \param record_type record type (23 for application data, etc).
* \param version record version.
* \param plaintext address of plaintext.
* \param len pointer to plaintext length (updated).
* \return pointer to start of built record.
*/
unsigned char *(*encrypt)(const br_sslrec_out_class **ctx,
int record_type, unsigned version,
void *plaintext, size_t *len);
};
/**
* \brief Context for a no-encryption engine.
*
* The no-encryption engine processes outgoing records during the initial
* handshake, before encryption is applied.
*/
typedef struct {
/** \brief No-encryption engine vtable. */
const br_sslrec_out_class *vtable;
} br_sslrec_out_clear_context;
/** \brief Static, constant vtable for the no-encryption engine. */
extern const br_sslrec_out_class br_sslrec_out_clear_vtable;
/* ===================================================================== */
/**
* \brief Record decryption engine class, for CBC mode.
*
* This class type extends the decryption engine class with an
* initialisation method that receives the parameters needed
* for CBC processing: block cipher implementation, block cipher key,
* HMAC parameters (hash function, key, MAC length), and IV. If the
* IV is `NULL`, then a per-record IV will be used (TLS 1.1+).
*/
typedef struct br_sslrec_in_cbc_class_ br_sslrec_in_cbc_class;
struct br_sslrec_in_cbc_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_in_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CBC decryption).
* \param bc_key block cipher key.
* \param bc_key_len block cipher key length (in bytes).
* \param dig_impl hash function for HMAC.
* \param mac_key HMAC key.
* \param mac_key_len HMAC key length (in bytes).
* \param mac_out_len HMAC output length (in bytes).
* \param iv initial IV (or `NULL`).
*/
void (*init)(const br_sslrec_in_cbc_class **ctx,
const br_block_cbcdec_class *bc_impl,
const void *bc_key, size_t bc_key_len,
const br_hash_class *dig_impl,
const void *mac_key, size_t mac_key_len, size_t mac_out_len,
const void *iv);
};
/**
* \brief Record encryption engine class, for CBC mode.
*
* This class type extends the encryption engine class with an
* initialisation method that receives the parameters needed
* for CBC processing: block cipher implementation, block cipher key,
* HMAC parameters (hash function, key, MAC length), and IV. If the
* IV is `NULL`, then a per-record IV will be used (TLS 1.1+).
*/
typedef struct br_sslrec_out_cbc_class_ br_sslrec_out_cbc_class;
struct br_sslrec_out_cbc_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_out_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CBC encryption).
* \param bc_key block cipher key.
* \param bc_key_len block cipher key length (in bytes).
* \param dig_impl hash function for HMAC.
* \param mac_key HMAC key.
* \param mac_key_len HMAC key length (in bytes).
* \param mac_out_len HMAC output length (in bytes).
* \param iv initial IV (or `NULL`).
*/
void (*init)(const br_sslrec_out_cbc_class **ctx,
const br_block_cbcenc_class *bc_impl,
const void *bc_key, size_t bc_key_len,
const br_hash_class *dig_impl,
const void *mac_key, size_t mac_key_len, size_t mac_out_len,
const void *iv);
};
/**
* \brief Context structure for decrypting incoming records with
* CBC + HMAC.
*
* The first field points to the vtable. The other fields are opaque
* and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_sslrec_in_cbc_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
uint64_t seq;
union {
const br_block_cbcdec_class *vtable;
br_aes_gen_cbcdec_keys aes;
br_des_gen_cbcdec_keys des;
} bc;
br_hmac_key_context mac;
size_t mac_len;
unsigned char iv[16];
int explicit_IV;
#endif
} br_sslrec_in_cbc_context;
/**
* \brief Static, constant vtable for record decryption with CBC.
*/
extern const br_sslrec_in_cbc_class br_sslrec_in_cbc_vtable;
/**
* \brief Context structure for encrypting outgoing records with
* CBC + HMAC.
*
* The first field points to the vtable. The other fields are opaque
* and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_sslrec_out_cbc_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
uint64_t seq;
union {
const br_block_cbcenc_class *vtable;
br_aes_gen_cbcenc_keys aes;
br_des_gen_cbcenc_keys des;
} bc;
br_hmac_key_context mac;
size_t mac_len;
unsigned char iv[16];
int explicit_IV;
#endif
} br_sslrec_out_cbc_context;
/**
* \brief Static, constant vtable for record encryption with CBC.
*/
extern const br_sslrec_out_cbc_class br_sslrec_out_cbc_vtable;
/* ===================================================================== */
/**
* \brief Record decryption engine class, for GCM mode.
*
* This class type extends the decryption engine class with an
* initialisation method that receives the parameters needed
* for GCM processing: block cipher implementation, block cipher key,
* GHASH implementation, and 4-byte IV.
*/
typedef struct br_sslrec_in_gcm_class_ br_sslrec_in_gcm_class;
struct br_sslrec_in_gcm_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_in_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CTR).
* \param key block cipher key.
* \param key_len block cipher key length (in bytes).
* \param gh_impl GHASH implementation.
* \param iv static IV (4 bytes).
*/
void (*init)(const br_sslrec_in_gcm_class **ctx,
const br_block_ctr_class *bc_impl,
const void *key, size_t key_len,
br_ghash gh_impl,
const void *iv);
};
/**
* \brief Record encryption engine class, for GCM mode.
*
* This class type extends the encryption engine class with an
* initialisation method that receives the parameters needed
* for GCM processing: block cipher implementation, block cipher key,
* GHASH implementation, and 4-byte IV.
*/
typedef struct br_sslrec_out_gcm_class_ br_sslrec_out_gcm_class;
struct br_sslrec_out_gcm_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_out_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CTR).
* \param key block cipher key.
* \param key_len block cipher key length (in bytes).
* \param gh_impl GHASH implementation.
* \param iv static IV (4 bytes).
*/
void (*init)(const br_sslrec_out_gcm_class **ctx,
const br_block_ctr_class *bc_impl,
const void *key, size_t key_len,
br_ghash gh_impl,
const void *iv);
};
/**
* \brief Context structure for processing records with GCM.
*
* The same context structure is used for encrypting and decrypting.
*
* The first field points to the vtable. The other fields are opaque
* and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
union {
const void *gen;
const br_sslrec_in_gcm_class *in;
const br_sslrec_out_gcm_class *out;
} vtable;
#ifndef BR_DOXYGEN_IGNORE
uint64_t seq;
union {
const br_block_ctr_class *vtable;
br_aes_gen_ctr_keys aes;
} bc;
br_ghash gh;
unsigned char iv[4];
unsigned char h[16];
#endif
} br_sslrec_gcm_context;
/**
* \brief Static, constant vtable for record decryption with GCM.
*/
extern const br_sslrec_in_gcm_class br_sslrec_in_gcm_vtable;
/**
* \brief Static, constant vtable for record encryption with GCM.
*/
extern const br_sslrec_out_gcm_class br_sslrec_out_gcm_vtable;
/* ===================================================================== */
/**
* \brief Record decryption engine class, for ChaCha20+Poly1305.
*
* This class type extends the decryption engine class with an
* initialisation method that receives the parameters needed
* for ChaCha20+Poly1305 processing: ChaCha20 implementation,
* Poly1305 implementation, key, and 12-byte IV.
*/
typedef struct br_sslrec_in_chapol_class_ br_sslrec_in_chapol_class;
struct br_sslrec_in_chapol_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_in_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param ichacha ChaCha20 implementation.
* \param ipoly Poly1305 implementation.
* \param key secret key (32 bytes).
* \param iv static IV (12 bytes).
*/
void (*init)(const br_sslrec_in_chapol_class **ctx,
br_chacha20_run ichacha,
br_poly1305_run ipoly,
const void *key, const void *iv);
};
/**
* \brief Record encryption engine class, for ChaCha20+Poly1305.
*
* This class type extends the encryption engine class with an
* initialisation method that receives the parameters needed
* for ChaCha20+Poly1305 processing: ChaCha20 implementation,
* Poly1305 implementation, key, and 12-byte IV.
*/
typedef struct br_sslrec_out_chapol_class_ br_sslrec_out_chapol_class;
struct br_sslrec_out_chapol_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_out_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param ichacha ChaCha20 implementation.
* \param ipoly Poly1305 implementation.
* \param key secret key (32 bytes).
* \param iv static IV (12 bytes).
*/
void (*init)(const br_sslrec_out_chapol_class **ctx,
br_chacha20_run ichacha,
br_poly1305_run ipoly,
const void *key, const void *iv);
};
/**
* \brief Context structure for processing records with ChaCha20+Poly1305.
*
* The same context structure is used for encrypting and decrypting.
*
* The first field points to the vtable. The other fields are opaque
* and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
union {
const void *gen;
const br_sslrec_in_chapol_class *in;
const br_sslrec_out_chapol_class *out;
} vtable;
#ifndef BR_DOXYGEN_IGNORE
uint64_t seq;
unsigned char key[32];
unsigned char iv[12];
br_chacha20_run ichacha;
br_poly1305_run ipoly;
#endif
} br_sslrec_chapol_context;
/**
* \brief Static, constant vtable for record decryption with ChaCha20+Poly1305.
*/
extern const br_sslrec_in_chapol_class br_sslrec_in_chapol_vtable;
/**
* \brief Static, constant vtable for record encryption with ChaCha20+Poly1305.
*/
extern const br_sslrec_out_chapol_class br_sslrec_out_chapol_vtable;
/* ===================================================================== */
/**
* \brief Record decryption engine class, for CCM mode.
*
* This class type extends the decryption engine class with an
* initialisation method that receives the parameters needed
* for CCM processing: block cipher implementation, block cipher key,
* and 4-byte IV.
*/
typedef struct br_sslrec_in_ccm_class_ br_sslrec_in_ccm_class;
struct br_sslrec_in_ccm_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_in_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CTR+CBC).
* \param key block cipher key.
* \param key_len block cipher key length (in bytes).
* \param iv static IV (4 bytes).
* \param tag_len tag length (in bytes)
*/
void (*init)(const br_sslrec_in_ccm_class **ctx,
const br_block_ctrcbc_class *bc_impl,
const void *key, size_t key_len,
const void *iv, size_t tag_len);
};
/**
* \brief Record encryption engine class, for CCM mode.
*
* This class type extends the encryption engine class with an
* initialisation method that receives the parameters needed
* for CCM processing: block cipher implementation, block cipher key,
* and 4-byte IV.
*/
typedef struct br_sslrec_out_ccm_class_ br_sslrec_out_ccm_class;
struct br_sslrec_out_ccm_class_ {
/**
* \brief Superclass, as first vtable field.
*/
br_sslrec_out_class inner;
/**
* \brief Engine initialisation method.
*
* This method sets the vtable field in the context.
*
* \param ctx context to initialise.
* \param bc_impl block cipher implementation (CTR+CBC).
* \param key block cipher key.
* \param key_len block cipher key length (in bytes).
* \param iv static IV (4 bytes).
* \param tag_len tag length (in bytes)
*/
void (*init)(const br_sslrec_out_ccm_class **ctx,
const br_block_ctrcbc_class *bc_impl,
const void *key, size_t key_len,
const void *iv, size_t tag_len);
};
/**
* \brief Context structure for processing records with CCM.
*
* The same context structure is used for encrypting and decrypting.
*
* The first field points to the vtable. The other fields are opaque
* and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
union {
const void *gen;
const br_sslrec_in_ccm_class *in;
const br_sslrec_out_ccm_class *out;
} vtable;
#ifndef BR_DOXYGEN_IGNORE
uint64_t seq;
union {
const br_block_ctrcbc_class *vtable;
br_aes_gen_ctrcbc_keys aes;
} bc;
unsigned char iv[4];
size_t tag_len;
#endif
} br_sslrec_ccm_context;
/**
* \brief Static, constant vtable for record decryption with CCM.
*/
extern const br_sslrec_in_ccm_class br_sslrec_in_ccm_vtable;
/**
* \brief Static, constant vtable for record encryption with CCM.
*/
extern const br_sslrec_out_ccm_class br_sslrec_out_ccm_vtable;
/* ===================================================================== */
/**
* \brief Type for session parameters, to be saved for session resumption.
*/
typedef struct {
/** \brief Session ID buffer. */
unsigned char session_id[32];
/** \brief Session ID length (in bytes, at most 32). */
unsigned char session_id_len;
/** \brief Protocol version. */
uint16_t version;
/** \brief Cipher suite. */
uint16_t cipher_suite;
/** \brief Master secret. */
unsigned char master_secret[48];
} br_ssl_session_parameters;
#ifndef BR_DOXYGEN_IGNORE
/*
* Maximum number of cipher suites supported by a client or server.
*/
#define BR_MAX_CIPHER_SUITES 48
#endif
/**
* \brief Context structure for SSL engine.
*
* This strucuture is common to the client and server; both the client
* context (`br_ssl_client_context`) and the server context
* (`br_ssl_server_context`) include a `br_ssl_engine_context` as their
* first field.
*
* The engine context manages records, including alerts, closures, and
* transitions to new encryption/MAC algorithms. Processing of handshake
* records is delegated to externally provided code. This structure
* should not be used directly.
*
* Structure contents are opaque and shall not be accessed directly.
*/
typedef struct {
#ifndef BR_DOXYGEN_IGNORE
/*
* The error code. When non-zero, then the state is "failed" and
* no I/O may occur until reset.
*/
int err;
/*
* Configured I/O buffers. They are either disjoint, or identical.
*/
unsigned char *ibuf, *obuf;
size_t ibuf_len, obuf_len;
/*
* Maximum fragment length applies to outgoing records; incoming
* records can be processed as long as they fit in the input
* buffer. It is guaranteed that incoming records at least as big
* as max_frag_len can be processed.
*/
uint16_t max_frag_len;
unsigned char log_max_frag_len;
unsigned char peer_log_max_frag_len;
/*
* Buffering management registers.
*/
size_t ixa, ixb, ixc;
size_t oxa, oxb, oxc;
unsigned char iomode;
unsigned char incrypt;
/*
* Shutdown flag: when set to non-zero, incoming record bytes
* will not be accepted anymore. This is used after a close_notify
* has been received: afterwards, the engine no longer claims that
* it could receive bytes from the transport medium.
*/
unsigned char shutdown_recv;
/*
* 'record_type_in' is set to the incoming record type when the
* record header has been received.
* 'record_type_out' is used to make the next outgoing record
* header when it is ready to go.
*/
unsigned char record_type_in, record_type_out;
/*
* When a record is received, its version is extracted:
* -- if 'version_in' is 0, then it is set to the received version;
* -- otherwise, if the received version is not identical to
* the 'version_in' contents, then a failure is reported.
*
* This implements the SSL requirement that all records shall
* use the negotiated protocol version, once decided (in the
* ServerHello). It is up to the handshake handler to adjust this
* field when necessary.
*/
uint16_t version_in;
/*
* 'version_out' is used when the next outgoing record is ready
* to go.
*/
uint16_t version_out;
/*
* Record handler contexts.
*/
union {
const br_sslrec_in_class *vtable;
br_sslrec_in_cbc_context cbc;
br_sslrec_gcm_context gcm;
br_sslrec_chapol_context chapol;
br_sslrec_ccm_context ccm;
} in;
union {
const br_sslrec_out_class *vtable;
br_sslrec_out_clear_context clear;
br_sslrec_out_cbc_context cbc;
br_sslrec_gcm_context gcm;
br_sslrec_chapol_context chapol;
br_sslrec_ccm_context ccm;
} out;
/*
* The "application data" flag. Value:
* 0 handshake is in process, no application data acceptable
* 1 application data can be sent and received
* 2 closing, no application data can be sent, but some
* can still be received (and discarded)
*/
unsigned char application_data;
/*
* Context RNG.
*
* rng_init_done is initially 0. It is set to 1 when the
* basic structure of the RNG is set, and 2 when some
* entropy has been pushed in. The value 2 marks the RNG
* as "properly seeded".
*
* rng_os_rand_done is initially 0. It is set to 1 when
* some seeding from the OS or hardware has been attempted.
*/
br_hmac_drbg_context rng;
int rng_init_done;
int rng_os_rand_done;
/*
* Supported minimum and maximum versions, and cipher suites.
*/
uint16_t version_min;
uint16_t version_max;
uint16_t suites_buf[BR_MAX_CIPHER_SUITES];
unsigned char suites_num;
/*
* For clients, the server name to send as a SNI extension. For
* servers, the name received in the SNI extension (if any).
*/
char server_name[256];
/*
* "Security parameters". These are filled by the handshake
* handler, and used when switching encryption state.
*/
unsigned char client_random[32];
unsigned char server_random[32];
br_ssl_session_parameters session;
/*
* ECDHE elements: curve and point from the peer. The server also
* uses that buffer for the point to send to the client.
*/
unsigned char ecdhe_curve;
unsigned char ecdhe_point[133];
unsigned char ecdhe_point_len;
/*
* Secure renegotiation (RFC 5746): 'reneg' can be:
* 0 first handshake (server support is not known)
* 1 peer does not support secure renegotiation
* 2 peer supports secure renegotiation
*
* The saved_finished buffer contains the client and the
* server "Finished" values from the last handshake, in
* that order (12 bytes each).
*/
unsigned char reneg;
unsigned char saved_finished[24];
/*
* Behavioural flags.
*/
uint32_t flags;
/*
* Context variables for the handshake processor. The 'pad' must
* be large enough to accommodate an RSA-encrypted pre-master
* secret, or an RSA signature; since we want to support up to
* RSA-4096, this means at least 512 bytes. (Other pad usages
* require its length to be at least 256.)
*/
struct {
uint32_t *dp;
uint32_t *rp;
const unsigned char *ip;
} cpu;
uint32_t dp_stack[32];
uint32_t rp_stack[32];
unsigned char pad[512];
unsigned char *hbuf_in, *hbuf_out, *saved_hbuf_out;
size_t hlen_in, hlen_out;
void (*hsrun)(void *ctx);
/*
* The 'action' value communicates OOB information between the
* engine and the handshake processor.
*
* From the engine:
* 0 invocation triggered by I/O
* 1 invocation triggered by explicit close
* 2 invocation triggered by explicit renegotiation
*/
unsigned char action;
/*
* State for alert messages. Value is either 0, or the value of
* the alert level byte (level is either 1 for warning, or 2 for
* fatal; we convert all other values to 'fatal').
*/
unsigned char alert;
/*
* Closure flags. This flag is set when a close_notify has been
* received from the peer.
*/
unsigned char close_received;
/*
* Multi-hasher for the handshake messages. The handshake handler
* is responsible for resetting it when appropriate.
*/
br_multihash_context mhash;
/*
* Pointer to the X.509 engine. The engine is supposed to be
* already initialized. It is used to validate the peer's
* certificate.
*/
const br_x509_class **x509ctx;
/*
* Certificate chain to send. This is used by both client and
* server, when they send their respective Certificate messages.
* If chain_len is 0, then chain may be NULL.
*/
const br_x509_certificate *chain;
size_t chain_len;
const unsigned char *cert_cur;
size_t cert_len;
/*
* List of supported protocol names (ALPN extension). If unset,
* (number of names is 0), then:
* - the client sends no ALPN extension;
* - the server ignores any incoming ALPN extension.
*
* Otherwise:
* - the client sends an ALPN extension with all the names;
* - the server selects the first protocol in its list that
* the client also supports, or fails (fatal alert 120)
* if the client sends an ALPN extension and there is no
* match.
*
* The 'selected_protocol' field contains 1+n if the matching
* name has index n in the list (the value is 0 if no match was
* performed, e.g. the peer did not send an ALPN extension).
*/
const char **protocol_names;
uint16_t protocol_names_num;
uint16_t selected_protocol;
/*
* Pointers to implementations; left to NULL for unsupported
* functions. For the raw hash functions, implementations are
* referenced from the multihasher (mhash field).
*/
br_tls_prf_impl prf10;
br_tls_prf_impl prf_sha256;
br_tls_prf_impl prf_sha384;
const br_block_cbcenc_class *iaes_cbcenc;
const br_block_cbcdec_class *iaes_cbcdec;
const br_block_ctr_class *iaes_ctr;
const br_block_ctrcbc_class *iaes_ctrcbc;
const br_block_cbcenc_class *ides_cbcenc;
const br_block_cbcdec_class *ides_cbcdec;
br_ghash ighash;
br_chacha20_run ichacha;
br_poly1305_run ipoly;
const br_sslrec_in_cbc_class *icbc_in;
const br_sslrec_out_cbc_class *icbc_out;
const br_sslrec_in_gcm_class *igcm_in;
const br_sslrec_out_gcm_class *igcm_out;
const br_sslrec_in_chapol_class *ichapol_in;
const br_sslrec_out_chapol_class *ichapol_out;
const br_sslrec_in_ccm_class *iccm_in;
const br_sslrec_out_ccm_class *iccm_out;
const br_ec_impl *iec;
br_rsa_pkcs1_vrfy irsavrfy;
br_ecdsa_vrfy iecdsa;
#endif
} br_ssl_engine_context;
/**
* \brief Get currently defined engine behavioural flags.
*
* \param cc SSL engine context.
* \return the flags.
*/
static inline uint32_t
br_ssl_engine_get_flags(br_ssl_engine_context *cc)
{
return cc->flags;
}
/**
* \brief Set all engine behavioural flags.
*
* \param cc SSL engine context.
* \param flags new value for all flags.
*/
static inline void
br_ssl_engine_set_all_flags(br_ssl_engine_context *cc, uint32_t flags)
{
cc->flags = flags;
}
/**
* \brief Set some engine behavioural flags.
*
* The flags set in the `flags` parameter are set in the context; other
* flags are untouched.
*
* \param cc SSL engine context.
* \param flags additional set flags.
*/
static inline void
br_ssl_engine_add_flags(br_ssl_engine_context *cc, uint32_t flags)
{
cc->flags |= flags;
}
/**
* \brief Clear some engine behavioural flags.
*
* The flags set in the `flags` parameter are cleared from the context; other
* flags are untouched.
*
* \param cc SSL engine context.
* \param flags flags to remove.
*/
static inline void
br_ssl_engine_remove_flags(br_ssl_engine_context *cc, uint32_t flags)
{
cc->flags &= ~flags;
}
/**
* \brief Behavioural flag: enforce server preferences.
*
* If this flag is set, then the server will enforce its own cipher suite
* preference order; otherwise, it follows the client preferences.
*/
#define BR_OPT_ENFORCE_SERVER_PREFERENCES ((uint32_t)1 << 0)
/**
* \brief Behavioural flag: disable renegotiation.
*
* If this flag is set, then renegotiations are rejected unconditionally:
* they won't be honoured if asked for programmatically, and requests from
* the peer are rejected.
*/
#define BR_OPT_NO_RENEGOTIATION ((uint32_t)1 << 1)
/**
* \brief Behavioural flag: tolerate lack of client authentication.
*
* If this flag is set in a server and the server requests a client
* certificate, but the authentication fails (the client does not send
* a certificate, or the client's certificate chain cannot be validated),
* then the connection keeps on. Without this flag, a failed client
* authentication terminates the connection.
*
* Notes:
*
* - If the client's certificate can be validated and its public key is
* supported, then a wrong signature value terminates the connection
* regardless of that flag.
*
* - If using full-static ECDH, then a failure to validate the client's
* certificate prevents the handshake from succeeding.
*/
#define BR_OPT_TOLERATE_NO_CLIENT_AUTH ((uint32_t)1 << 2)
/**
* \brief Behavioural flag: fail on application protocol mismatch.
*
* The ALPN extension ([RFC 7301](https://tools.ietf.org/html/rfc7301))
* allows the client to send a list of application protocol names, and
* the server to select one. A mismatch is one of the following occurrences:
*
* - On the client: the client sends a list of names, the server
* responds with a protocol name which is _not_ part of the list of
* names sent by the client.
*
* - On the server: the client sends a list of names, and the server
* is also configured with a list of names, but there is no common
* protocol name between the two lists.
*
* Normal behaviour in case of mismatch is to report no matching name
* (`br_ssl_engine_get_selected_protocol()` returns `NULL`) and carry on.
* If the flag is set, then a mismatch implies a protocol failure (if
* the mismatch is detected by the server, it will send a fatal alert).
*
* Note: even with this flag, `br_ssl_engine_get_selected_protocol()`
* may still return `NULL` if the client or the server does not send an
* ALPN extension at all.
*/
#define BR_OPT_FAIL_ON_ALPN_MISMATCH ((uint32_t)1 << 3)
/**
* \brief Set the minimum and maximum supported protocol versions.
*
* The two provided versions MUST be supported by the implementation
* (i.e. TLS 1.0, 1.1 and 1.2), and `version_max` MUST NOT be lower
* than `version_min`.
*
* \param cc SSL engine context.
* \param version_min minimum supported TLS version.
* \param version_max maximum supported TLS version.
*/
static inline void
br_ssl_engine_set_versions(br_ssl_engine_context *cc,
unsigned version_min, unsigned version_max)
{
cc->version_min = version_min;
cc->version_max = version_max;
}
/**
* \brief Set the list of cipher suites advertised by this context.
*
* The provided array is copied into the context. It is the caller
* responsibility to ensure that all provided suites will be supported
* by the context. The engine context has enough room to receive _all_
* suites supported by the implementation. The provided array MUST NOT
* contain duplicates.
*
* If the engine is for a client, the "signaling" pseudo-cipher suite
* `TLS_FALLBACK_SCSV` can be added at the end of the list, if the
* calling application is performing a voluntary downgrade (voluntary
* downgrades are not recommended, but if such a downgrade is done, then
* adding the fallback pseudo-suite is a good idea).
*
* \param cc SSL engine context.
* \param suites cipher suites.
* \param suites_num number of cipher suites.
*/
void br_ssl_engine_set_suites(br_ssl_engine_context *cc,
const uint16_t *suites, size_t suites_num);
/**
* \brief Set the X.509 engine.
*
* The caller shall ensure that the X.509 engine is properly initialised.
*
* \param cc SSL engine context.
* \param x509ctx X.509 certificate validation context.
*/
static inline void
br_ssl_engine_set_x509(br_ssl_engine_context *cc, const br_x509_class **x509ctx)
{
cc->x509ctx = x509ctx;
}
/**
* \brief Set the supported protocol names.
*
* Protocol names are part of the ALPN extension ([RFC
* 7301](https://tools.ietf.org/html/rfc7301)). Each protocol name is a
* character string, containing no more than 255 characters (256 with the
* terminating zero). When names are set, then:
*
* - The client will send an ALPN extension, containing the names. If
* the server responds with an ALPN extension, the client will verify
* that the response contains one of its name, and report that name
* through `br_ssl_engine_get_selected_protocol()`.
*
* - The server will parse incoming ALPN extension (from clients), and
* try to find a common protocol; if none is found, the connection
* is aborted with a fatal alert. On match, a response ALPN extension
* is sent, and name is reported through
* `br_ssl_engine_get_selected_protocol()`.
*
* The provided array is linked in, and must remain valid while the
* connection is live.
*
* Names MUST NOT be empty. Names MUST NOT be longer than 255 characters
* (excluding the terminating 0).
*
* \param ctx SSL engine context.
* \param names list of protocol names (zero-terminated).
* \param num number of protocol names (MUST be 1 or more).
*/
static inline void
br_ssl_engine_set_protocol_names(br_ssl_engine_context *ctx,
const char **names, size_t num)
{
ctx->protocol_names = names;
ctx->protocol_names_num = num;
}
/**
* \brief Get the selected protocol.
*
* If this context was initialised with a non-empty list of protocol
* names, and both client and server sent ALPN extensions during the
* handshake, and a common name was found, then that name is returned.
* Otherwise, `NULL` is returned.
*
* The returned pointer is one of the pointers provided to the context
* with `br_ssl_engine_set_protocol_names()`.
*
* \return the selected protocol, or `NULL`.
*/
static inline const char *
br_ssl_engine_get_selected_protocol(br_ssl_engine_context *ctx)
{
unsigned k;
k = ctx->selected_protocol;
return (k == 0 || k == 0xFFFF) ? NULL : ctx->protocol_names[k - 1];
}
/**
* \brief Set a hash function implementation (by ID).
*
* Hash functions set with this call will be used for SSL/TLS specific
* usages, not X.509 certificate validation. Only "standard" hash functions
* may be set (MD5, SHA-1, SHA-224, SHA-256, SHA-384, SHA-512). If `impl`
* is `NULL`, then the hash function support is removed, not added.
*
* \param ctx SSL engine context.
* \param id hash function identifier.
* \param impl hash function implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_hash(br_ssl_engine_context *ctx,
int id, const br_hash_class *impl)
{
br_multihash_setimpl(&ctx->mhash, id, impl);
}
/**
* \brief Get a hash function implementation (by ID).
*
* This function retrieves a hash function implementation which was
* set with `br_ssl_engine_set_hash()`.
*
* \param ctx SSL engine context.
* \param id hash function identifier.
* \return the hash function implementation (or `NULL`).
*/
static inline const br_hash_class *
br_ssl_engine_get_hash(br_ssl_engine_context *ctx, int id)
{
return br_multihash_getimpl(&ctx->mhash, id);
}
/**
* \brief Set the PRF implementation (for TLS 1.0 and 1.1).
*
* This function sets (or removes, if `impl` is `NULL`) the implementation
* for the PRF used in TLS 1.0 and 1.1.
*
* \param cc SSL engine context.
* \param impl PRF implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_prf10(br_ssl_engine_context *cc, br_tls_prf_impl impl)
{
cc->prf10 = impl;
}
/**
* \brief Set the PRF implementation with SHA-256 (for TLS 1.2).
*
* This function sets (or removes, if `impl` is `NULL`) the implementation
* for the SHA-256 variant of the PRF used in TLS 1.2.
*
* \param cc SSL engine context.
* \param impl PRF implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_prf_sha256(br_ssl_engine_context *cc, br_tls_prf_impl impl)
{
cc->prf_sha256 = impl;
}
/**
* \brief Set the PRF implementation with SHA-384 (for TLS 1.2).
*
* This function sets (or removes, if `impl` is `NULL`) the implementation
* for the SHA-384 variant of the PRF used in TLS 1.2.
*
* \param cc SSL engine context.
* \param impl PRF implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_prf_sha384(br_ssl_engine_context *cc, br_tls_prf_impl impl)
{
cc->prf_sha384 = impl;
}
/**
* \brief Set the AES/CBC implementations.
*
* \param cc SSL engine context.
* \param impl_enc AES/CBC encryption implementation (or `NULL`).
* \param impl_dec AES/CBC decryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_aes_cbc(br_ssl_engine_context *cc,
const br_block_cbcenc_class *impl_enc,
const br_block_cbcdec_class *impl_dec)
{
cc->iaes_cbcenc = impl_enc;
cc->iaes_cbcdec = impl_dec;
}
/**
* \brief Set the "default" AES/CBC implementations.
*
* This function configures in the engine the AES implementations that
* should provide best runtime performance on the local system, while
* still being safe (in particular, constant-time). It also sets the
* handlers for CBC records.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_aes_cbc(br_ssl_engine_context *cc);
/**
* \brief Set the AES/CTR implementation.
*
* \param cc SSL engine context.
* \param impl AES/CTR encryption/decryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_aes_ctr(br_ssl_engine_context *cc,
const br_block_ctr_class *impl)
{
cc->iaes_ctr = impl;
}
/**
* \brief Set the "default" implementations for AES/GCM (AES/CTR + GHASH).
*
* This function configures in the engine the AES/CTR and GHASH
* implementation that should provide best runtime performance on the local
* system, while still being safe (in particular, constant-time). It also
* sets the handlers for GCM records.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_aes_gcm(br_ssl_engine_context *cc);
/**
* \brief Set the DES/CBC implementations.
*
* \param cc SSL engine context.
* \param impl_enc DES/CBC encryption implementation (or `NULL`).
* \param impl_dec DES/CBC decryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_des_cbc(br_ssl_engine_context *cc,
const br_block_cbcenc_class *impl_enc,
const br_block_cbcdec_class *impl_dec)
{
cc->ides_cbcenc = impl_enc;
cc->ides_cbcdec = impl_dec;
}
/**
* \brief Set the "default" DES/CBC implementations.
*
* This function configures in the engine the DES implementations that
* should provide best runtime performance on the local system, while
* still being safe (in particular, constant-time). It also sets the
* handlers for CBC records.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_des_cbc(br_ssl_engine_context *cc);
/**
* \brief Set the GHASH implementation (used in GCM mode).
*
* \param cc SSL engine context.
* \param impl GHASH implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_ghash(br_ssl_engine_context *cc, br_ghash impl)
{
cc->ighash = impl;
}
/**
* \brief Set the ChaCha20 implementation.
*
* \param cc SSL engine context.
* \param ichacha ChaCha20 implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_chacha20(br_ssl_engine_context *cc,
br_chacha20_run ichacha)
{
cc->ichacha = ichacha;
}
/**
* \brief Set the Poly1305 implementation.
*
* \param cc SSL engine context.
* \param ipoly Poly1305 implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_poly1305(br_ssl_engine_context *cc,
br_poly1305_run ipoly)
{
cc->ipoly = ipoly;
}
/**
* \brief Set the "default" ChaCha20 and Poly1305 implementations.
*
* This function configures in the engine the ChaCha20 and Poly1305
* implementations that should provide best runtime performance on the
* local system, while still being safe (in particular, constant-time).
* It also sets the handlers for ChaCha20+Poly1305 records.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_chapol(br_ssl_engine_context *cc);
/**
* \brief Set the AES/CTR+CBC implementation.
*
* \param cc SSL engine context.
* \param impl AES/CTR+CBC encryption/decryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_aes_ctrcbc(br_ssl_engine_context *cc,
const br_block_ctrcbc_class *impl)
{
cc->iaes_ctrcbc = impl;
}
/**
* \brief Set the "default" implementations for AES/CCM.
*
* This function configures in the engine the AES/CTR+CBC
* implementation that should provide best runtime performance on the local
* system, while still being safe (in particular, constant-time). It also
* sets the handlers for CCM records.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_aes_ccm(br_ssl_engine_context *cc);
/**
* \brief Set the record encryption and decryption engines for CBC + HMAC.
*
* \param cc SSL engine context.
* \param impl_in record CBC decryption implementation (or `NULL`).
* \param impl_out record CBC encryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_cbc(br_ssl_engine_context *cc,
const br_sslrec_in_cbc_class *impl_in,
const br_sslrec_out_cbc_class *impl_out)
{
cc->icbc_in = impl_in;
cc->icbc_out = impl_out;
}
/**
* \brief Set the record encryption and decryption engines for GCM.
*
* \param cc SSL engine context.
* \param impl_in record GCM decryption implementation (or `NULL`).
* \param impl_out record GCM encryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_gcm(br_ssl_engine_context *cc,
const br_sslrec_in_gcm_class *impl_in,
const br_sslrec_out_gcm_class *impl_out)
{
cc->igcm_in = impl_in;
cc->igcm_out = impl_out;
}
/**
* \brief Set the record encryption and decryption engines for CCM.
*
* \param cc SSL engine context.
* \param impl_in record CCM decryption implementation (or `NULL`).
* \param impl_out record CCM encryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_ccm(br_ssl_engine_context *cc,
const br_sslrec_in_ccm_class *impl_in,
const br_sslrec_out_ccm_class *impl_out)
{
cc->iccm_in = impl_in;
cc->iccm_out = impl_out;
}
/**
* \brief Set the record encryption and decryption engines for
* ChaCha20+Poly1305.
*
* \param cc SSL engine context.
* \param impl_in record ChaCha20 decryption implementation (or `NULL`).
* \param impl_out record ChaCha20 encryption implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_chapol(br_ssl_engine_context *cc,
const br_sslrec_in_chapol_class *impl_in,
const br_sslrec_out_chapol_class *impl_out)
{
cc->ichapol_in = impl_in;
cc->ichapol_out = impl_out;
}
/**
* \brief Set the EC implementation.
*
* The elliptic curve implementation will be used for ECDH and ECDHE
* cipher suites, and for ECDSA support.
*
* \param cc SSL engine context.
* \param iec EC implementation (or `NULL`).
*/
static inline void
br_ssl_engine_set_ec(br_ssl_engine_context *cc, const br_ec_impl *iec)
{
cc->iec = iec;
}
/**
* \brief Set the "default" EC implementation.
*
* This function sets the elliptic curve implementation for ECDH and
* ECDHE cipher suites, and for ECDSA support. It selects the fastest
* implementation on the current system.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_ec(br_ssl_engine_context *cc);
/**
* \brief Get the EC implementation configured in the provided engine.
*
* \param cc SSL engine context.
* \return the EC implementation.
*/
static inline const br_ec_impl *
br_ssl_engine_get_ec(br_ssl_engine_context *cc)
{
return cc->iec;
}
/**
* \brief Set the RSA signature verification implementation.
*
* On the client, this is used to verify the server's signature on its
* ServerKeyExchange message (for ECDHE_RSA cipher suites). On the server,
* this is used to verify the client's CertificateVerify message (if a
* client certificate is requested, and that certificate contains a RSA key).
*
* \param cc SSL engine context.
* \param irsavrfy RSA signature verification implementation.
*/
static inline void
br_ssl_engine_set_rsavrfy(br_ssl_engine_context *cc, br_rsa_pkcs1_vrfy irsavrfy)
{
cc->irsavrfy = irsavrfy;
}
/**
* \brief Set the "default" RSA implementation (signature verification).
*
* This function sets the RSA implementation (signature verification)
* to the fastest implementation available on the current platform.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_rsavrfy(br_ssl_engine_context *cc);
/**
* \brief Get the RSA implementation (signature verification) configured
* in the provided engine.
*
* \param cc SSL engine context.
* \return the RSA signature verification implementation.
*/
static inline br_rsa_pkcs1_vrfy
br_ssl_engine_get_rsavrfy(br_ssl_engine_context *cc)
{
return cc->irsavrfy;
}
/*
* \brief Set the ECDSA implementation (signature verification).
*
* On the client, this is used to verify the server's signature on its
* ServerKeyExchange message (for ECDHE_ECDSA cipher suites). On the server,
* this is used to verify the client's CertificateVerify message (if a
* client certificate is requested, that certificate contains an EC key,
* and full-static ECDH is not used).
*
* The ECDSA implementation will use the EC core implementation configured
* in the engine context.
*
* \param cc client context.
* \param iecdsa ECDSA verification implementation.
*/
static inline void
br_ssl_engine_set_ecdsa(br_ssl_engine_context *cc, br_ecdsa_vrfy iecdsa)
{
cc->iecdsa = iecdsa;
}
/**
* \brief Set the "default" ECDSA implementation (signature verification).
*
* This function sets the ECDSA implementation (signature verification)
* to the fastest implementation available on the current platform. This
* call also sets the elliptic curve implementation itself, there again
* to the fastest EC implementation available.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_set_default_ecdsa(br_ssl_engine_context *cc);
/**
* \brief Get the ECDSA implementation (signature verification) configured
* in the provided engine.
*
* \param cc SSL engine context.
* \return the ECDSA signature verification implementation.
*/
static inline br_ecdsa_vrfy
br_ssl_engine_get_ecdsa(br_ssl_engine_context *cc)
{
return cc->iecdsa;
}
/**
* \brief Set the I/O buffer for the SSL engine.
*
* Once this call has been made, `br_ssl_client_reset()` or
* `br_ssl_server_reset()` MUST be called before using the context.
*
* The provided buffer will be used as long as the engine context is
* used. The caller is responsible for keeping it available.
*
* If `bidi` is 0, then the engine will operate in half-duplex mode
* (it won't be able to send data while there is unprocessed incoming
* data in the buffer, and it won't be able to receive data while there
* is unsent data in the buffer). The optimal buffer size in half-duplex
* mode is `BR_SSL_BUFSIZE_MONO`; if the buffer is larger, then extra
* bytes are ignored. If the buffer is smaller, then this limits the
* capacity of the engine to support all allowed record sizes.
*
* If `bidi` is 1, then the engine will split the buffer into two
* parts, for separate handling of outgoing and incoming data. This
* enables full-duplex processing, but requires more RAM. The optimal
* buffer size in full-duplex mode is `BR_SSL_BUFSIZE_BIDI`; if the
* buffer is larger, then extra bytes are ignored. If the buffer is
* smaller, then the split will favour the incoming part, so that
* interoperability is maximised.
*
* \param cc SSL engine context
* \param iobuf I/O buffer.
* \param iobuf_len I/O buffer length (in bytes).
* \param bidi non-zero for full-duplex mode.
*/
void br_ssl_engine_set_buffer(br_ssl_engine_context *cc,
void *iobuf, size_t iobuf_len, int bidi);
/**
* \brief Set the I/O buffers for the SSL engine.
*
* Once this call has been made, `br_ssl_client_reset()` or
* `br_ssl_server_reset()` MUST be called before using the context.
*
* This function is similar to `br_ssl_engine_set_buffer()`, except
* that it enforces full-duplex mode, and the two I/O buffers are
* provided as separate chunks.
*
* The macros `BR_SSL_BUFSIZE_INPUT` and `BR_SSL_BUFSIZE_OUTPUT`
* evaluate to the optimal (maximum) sizes for the input and output
* buffer, respectively.
*
* \param cc SSL engine context
* \param ibuf input buffer.
* \param ibuf_len input buffer length (in bytes).
* \param obuf output buffer.
* \param obuf_len output buffer length (in bytes).
*/
void br_ssl_engine_set_buffers_bidi(br_ssl_engine_context *cc,
void *ibuf, size_t ibuf_len, void *obuf, size_t obuf_len);
/**
* \brief Inject some "initial entropy" in the context.
*
* This entropy will be added to what can be obtained from the
* underlying operating system, if that OS is supported.
*
* This function may be called several times; all injected entropy chunks
* are cumulatively mixed.
*
* If entropy gathering from the OS is supported and compiled in, then this
* step is optional. Otherwise, it is mandatory to inject randomness, and
* the caller MUST take care to push (as one or several successive calls)
* enough entropy to achieve cryptographic resistance (at least 80 bits,
* preferably 128 or more). The engine will report an error if no entropy
* was provided and none can be obtained from the OS.
*
* Take care that this function cannot assess the cryptographic quality of
* the provided bytes.
*
* In all generality, "entropy" must here be considered to mean "that
* which the attacker cannot predict". If your OS/architecture does not
* have a suitable source of randomness, then you can make do with the
* combination of a large enough secret value (possibly a copy of an
* asymmetric private key that you also store on the system) AND a
* non-repeating value (e.g. current time, provided that the local clock
* cannot be reset or altered by the attacker).
*
* \param cc SSL engine context.
* \param data extra entropy to inject.
* \param len length of the extra data (in bytes).
*/
void br_ssl_engine_inject_entropy(br_ssl_engine_context *cc,
const void *data, size_t len);
/**
* \brief Get the "server name" in this engine.
*
* For clients, this is the name provided with `br_ssl_client_reset()`;
* for servers, this is the name received from the client as part of the
* ClientHello message. If there is no such name (e.g. the client did
* not send an SNI extension) then the returned string is empty
* (returned pointer points to a byte of value 0).
*
* The returned pointer refers to a buffer inside the context, which may
* be overwritten as part of normal SSL activity (even within the same
* connection, if a renegotiation occurs).
*
* \param cc SSL engine context.
* \return the server name (possibly empty).
*/
static inline const char *
br_ssl_engine_get_server_name(const br_ssl_engine_context *cc)
{
return cc->server_name;
}
/**
* \brief Get the protocol version.
*
* This function returns the protocol version that is used by the
* engine. That value is set after sending (for a server) or receiving
* (for a client) the ServerHello message.
*
* \param cc SSL engine context.
* \return the protocol version.
*/
static inline unsigned
br_ssl_engine_get_version(const br_ssl_engine_context *cc)
{
return cc->session.version;
}
/**
* \brief Get a copy of the session parameters.
*
* The session parameters are filled during the handshake, so this
* function shall not be called before completion of the handshake.
* The initial handshake is completed when the context first allows
* application data to be injected.
*
* This function copies the current session parameters into the provided
* structure. Beware that the session parameters include the master
* secret, which is sensitive data, to handle with great care.
*
* \param cc SSL engine context.
* \param pp destination structure for the session parameters.
*/
static inline void
br_ssl_engine_get_session_parameters(const br_ssl_engine_context *cc,
br_ssl_session_parameters *pp)
{
memcpy(pp, &cc->session, sizeof *pp);
}
/**
* \brief Set the session parameters to the provided values.
*
* This function is meant to be used in the client, before doing a new
* handshake; a session resumption will be attempted with these
* parameters. In the server, this function has no effect.
*
* \param cc SSL engine context.
* \param pp source structure for the session parameters.
*/
static inline void
br_ssl_engine_set_session_parameters(br_ssl_engine_context *cc,
const br_ssl_session_parameters *pp)
{
memcpy(&cc->session, pp, sizeof *pp);
}
/**
* \brief Get identifier for the curve used for key exchange.
*
* If the cipher suite uses ECDHE, then this function returns the
* identifier for the curve used for transient parameters. This is
* defined during the course of the handshake, when the ServerKeyExchange
* is sent (on the server) or received (on the client). If the
* cipher suite does not use ECDHE (e.g. static ECDH, or RSA key
* exchange), then this value is indeterminate.
*
* @param cc SSL engine context.
* @return the ECDHE curve identifier.
*/
static inline int
br_ssl_engine_get_ecdhe_curve(br_ssl_engine_context *cc)
{
return cc->ecdhe_curve;
}
/**
* \brief Get the current engine state.
*
* An SSL engine (client or server) has, at any time, a state which is
* the combination of zero, one or more of these flags:
*
* - `BR_SSL_CLOSED`
*
* Engine is finished, no more I/O (until next reset).
*
* - `BR_SSL_SENDREC`
*
* Engine has some bytes to send to the peer.
*
* - `BR_SSL_RECVREC`
*
* Engine expects some bytes from the peer.
*
* - `BR_SSL_SENDAPP`
*
* Engine may receive application data to send (or flush).
*
* - `BR_SSL_RECVAPP`
*
* Engine has obtained some application data from the peer,
* that should be read by the caller.
*
* If no flag at all is set (state value is 0), then the engine is not
* fully initialised yet.
*
* The `BR_SSL_CLOSED` flag is exclusive; when it is set, no other flag
* is set. To distinguish between a normal closure and an error, use
* `br_ssl_engine_last_error()`.
*
* Generally speaking, `BR_SSL_SENDREC` and `BR_SSL_SENDAPP` are mutually
* exclusive: the input buffer, at any point, either accumulates
* plaintext data, or contains an assembled record that is being sent.
* Similarly, `BR_SSL_RECVREC` and `BR_SSL_RECVAPP` are mutually exclusive.
* This may change in a future library version.
*
* \param cc SSL engine context.
* \return the current engine state.
*/
unsigned br_ssl_engine_current_state(const br_ssl_engine_context *cc);
/** \brief SSL engine state: closed or failed. */
#define BR_SSL_CLOSED 0x0001
/** \brief SSL engine state: record data is ready to be sent to the peer. */
#define BR_SSL_SENDREC 0x0002
/** \brief SSL engine state: engine may receive records from the peer. */
#define BR_SSL_RECVREC 0x0004
/** \brief SSL engine state: engine may accept application data to send. */
#define BR_SSL_SENDAPP 0x0008
/** \brief SSL engine state: engine has received application data. */
#define BR_SSL_RECVAPP 0x0010
/**
* \brief Get the engine error indicator.
*
* The error indicator is `BR_ERR_OK` (0) if no error was encountered
* since the last call to `br_ssl_client_reset()` or
* `br_ssl_server_reset()`. Other status values are "sticky": they
* remain set, and prevent all I/O activity, until cleared. Only the
* reset calls clear the error indicator.
*
* \param cc SSL engine context.
* \return 0, or a non-zero error code.
*/
static inline int
br_ssl_engine_last_error(const br_ssl_engine_context *cc)
{
return cc->err;
}
/*
* There are four I/O operations, each identified by a symbolic name:
*
* sendapp inject application data in the engine
* recvapp retrieving application data from the engine
* sendrec sending records on the transport medium
* recvrec receiving records from the transport medium
*
* Terminology works thus: in a layered model where the SSL engine sits
* between the application and the network, "send" designates operations
* where bytes flow from application to network, and "recv" for the
* reverse operation. Application data (the plaintext that is to be
* conveyed through SSL) is "app", while encrypted records are "rec".
* Note that from the SSL engine point of view, "sendapp" and "recvrec"
* designate bytes that enter the engine ("inject" operation), while
* "recvapp" and "sendrec" designate bytes that exit the engine
* ("extract" operation).
*
* For the operation 'xxx', two functions are defined:
*
* br_ssl_engine_xxx_buf
* Returns a pointer and length to the buffer to use for that
* operation. '*len' is set to the number of bytes that may be read
* from the buffer (extract operation) or written to the buffer
* (inject operation). If no byte may be exchanged for that operation
* at that point, then '*len' is set to zero, and NULL is returned.
* The engine state is unmodified by this call.
*
* br_ssl_engine_xxx_ack
* Informs the engine that 'len' bytes have been read from the buffer
* (extract operation) or written to the buffer (inject operation).
* The 'len' value MUST NOT be zero. The 'len' value MUST NOT exceed
* that which was obtained from a preceding br_ssl_engine_xxx_buf()
* call.
*/
/**
* \brief Get buffer for application data to send.
*
* If the engine is ready to accept application data to send to the
* peer, then this call returns a pointer to the buffer where such
* data shall be written, and its length is written in `*len`.
* Otherwise, `*len` is set to 0 and `NULL` is returned.
*
* \param cc SSL engine context.
* \param len receives the application data output buffer length, or 0.
* \return the application data output buffer, or `NULL`.
*/
unsigned char *br_ssl_engine_sendapp_buf(
const br_ssl_engine_context *cc, size_t *len);
/**
* \brief Inform the engine of some new application data.
*
* After writing `len` bytes in the buffer returned by
* `br_ssl_engine_sendapp_buf()`, the application shall call this
* function to trigger any relevant processing. The `len` parameter
* MUST NOT be 0, and MUST NOT exceed the value obtained in the
* `br_ssl_engine_sendapp_buf()` call.
*
* \param cc SSL engine context.
* \param len number of bytes pushed (not zero).
*/
void br_ssl_engine_sendapp_ack(br_ssl_engine_context *cc, size_t len);
/**
* \brief Get buffer for received application data.
*
* If the engine has received application data from the peer, hen this
* call returns a pointer to the buffer from where such data shall be
* read, and its length is written in `*len`. Otherwise, `*len` is set
* to 0 and `NULL` is returned.
*
* \param cc SSL engine context.
* \param len receives the application data input buffer length, or 0.
* \return the application data input buffer, or `NULL`.
*/
unsigned char *br_ssl_engine_recvapp_buf(
const br_ssl_engine_context *cc, size_t *len);
/**
* \brief Acknowledge some received application data.
*
* After reading `len` bytes from the buffer returned by
* `br_ssl_engine_recvapp_buf()`, the application shall call this
* function to trigger any relevant processing. The `len` parameter
* MUST NOT be 0, and MUST NOT exceed the value obtained in the
* `br_ssl_engine_recvapp_buf()` call.
*
* \param cc SSL engine context.
* \param len number of bytes read (not zero).
*/
void br_ssl_engine_recvapp_ack(br_ssl_engine_context *cc, size_t len);
/**
* \brief Get buffer for record data to send.
*
* If the engine has prepared some records to send to the peer, then this
* call returns a pointer to the buffer from where such data shall be
* read, and its length is written in `*len`. Otherwise, `*len` is set
* to 0 and `NULL` is returned.
*
* \param cc SSL engine context.
* \param len receives the record data output buffer length, or 0.
* \return the record data output buffer, or `NULL`.
*/
unsigned char *br_ssl_engine_sendrec_buf(
const br_ssl_engine_context *cc, size_t *len);
/**
* \brief Acknowledge some sent record data.
*
* After reading `len` bytes from the buffer returned by
* `br_ssl_engine_sendrec_buf()`, the application shall call this
* function to trigger any relevant processing. The `len` parameter
* MUST NOT be 0, and MUST NOT exceed the value obtained in the
* `br_ssl_engine_sendrec_buf()` call.
*
* \param cc SSL engine context.
* \param len number of bytes read (not zero).
*/
void br_ssl_engine_sendrec_ack(br_ssl_engine_context *cc, size_t len);
/**
* \brief Get buffer for incoming records.
*
* If the engine is ready to accept records from the peer, then this
* call returns a pointer to the buffer where such data shall be
* written, and its length is written in `*len`. Otherwise, `*len` is
* set to 0 and `NULL` is returned.
*
* \param cc SSL engine context.
* \param len receives the record data input buffer length, or 0.
* \return the record data input buffer, or `NULL`.
*/
unsigned char *br_ssl_engine_recvrec_buf(
const br_ssl_engine_context *cc, size_t *len);
/**
* \brief Inform the engine of some new record data.
*
* After writing `len` bytes in the buffer returned by
* `br_ssl_engine_recvrec_buf()`, the application shall call this
* function to trigger any relevant processing. The `len` parameter
* MUST NOT be 0, and MUST NOT exceed the value obtained in the
* `br_ssl_engine_recvrec_buf()` call.
*
* \param cc SSL engine context.
* \param len number of bytes pushed (not zero).
*/
void br_ssl_engine_recvrec_ack(br_ssl_engine_context *cc, size_t len);
/**
* \brief Flush buffered application data.
*
* If some application data has been buffered in the engine, then wrap
* it into a record and mark it for sending. If no application data has
* been buffered but the engine would be ready to accept some, AND the
* `force` parameter is non-zero, then an empty record is assembled and
* marked for sending. In all other cases, this function does nothing.
*
* Empty records are technically legal, but not all existing SSL/TLS
* implementations support them. Empty records can be useful as a
* transparent "keep-alive" mechanism to maintain some low-level
* network activity.
*
* \param cc SSL engine context.
* \param force non-zero to force sending an empty record.
*/
void br_ssl_engine_flush(br_ssl_engine_context *cc, int force);
/**
* \brief Initiate a closure.
*
* If, at that point, the context is open and in ready state, then a
* `close_notify` alert is assembled and marked for sending; this
* triggers the closure protocol. Otherwise, no such alert is assembled.
*
* \param cc SSL engine context.
*/
void br_ssl_engine_close(br_ssl_engine_context *cc);
/**
* \brief Initiate a renegotiation.
*
* If the engine is failed or closed, or if the peer is known not to
* support secure renegotiation (RFC 5746), or if renegotiations have
* been disabled with the `BR_OPT_NO_RENEGOTIATION` flag, or if there
* is buffered incoming application data, then this function returns 0
* and nothing else happens.
*
* Otherwise, this function returns 1, and a renegotiation attempt is
* triggered (if a handshake is already ongoing at that point, then
* no new handshake is triggered).
*
* \param cc SSL engine context.
* \return 1 on success, 0 on error.
*/
int br_ssl_engine_renegotiate(br_ssl_engine_context *cc);
/**
* \brief Export key material from a connected SSL engine (RFC 5705).
*
* This calls compute a secret key of arbitrary length from the master
* secret of a connected SSL engine. If the provided context is not
* currently in "application data" state (initial handshake is not
* finished, another handshake is ongoing, or the connection failed or
* was closed), then this function returns 0. Otherwise, a secret key of
* length `len` bytes is computed and written in the buffer pointed to
* by `dst`, and 1 is returned.
*
* The computed key follows the specification described in RFC 5705.
* That RFC includes two key computations, with and without a "context
* value". If `context` is `NULL`, then the variant without context is
* used; otherwise, the `context_len` bytes located at the address
* pointed to by `context` are used in the computation. Note that it
* is possible to have a "with context" key with a context length of
* zero bytes, by setting `context` to a non-`NULL` value but
* `context_len` to 0.
*
* When context bytes are used, the context length MUST NOT exceed
* 65535 bytes.
*
* \param cc SSL engine context.
* \param dst destination buffer for exported key.
* \param len exported key length (in bytes).
* \param label disambiguation label.
* \param context context value (or `NULL`).
* \param context_len context length (in bytes).
* \return 1 on success, 0 on error.
*/
int br_ssl_key_export(br_ssl_engine_context *cc,
void *dst, size_t len, const char *label,
const void *context, size_t context_len);
/*
* Pre-declaration for the SSL client context.
*/
typedef struct br_ssl_client_context_ br_ssl_client_context;
/**
* \brief Type for the client certificate, if requested by the server.
*/
typedef struct {
/**
* \brief Authentication type.
*
* This is either `BR_AUTH_RSA` (RSA signature), `BR_AUTH_ECDSA`
* (ECDSA signature), or `BR_AUTH_ECDH` (static ECDH key exchange).
*/
int auth_type;
/**
* \brief Hash function for computing the CertificateVerify.
*
* This is the symbolic identifier for the hash function that
* will be used to produce the hash of handshake messages, to
* be signed into the CertificateVerify. For full static ECDH
* (client and server certificates are both EC in the same
* curve, and static ECDH is used), this value is set to -1.
*
* Take care that with TLS 1.0 and 1.1, that value MUST match
* the protocol requirements: value must be 0 (MD5+SHA-1) for
* a RSA signature, or 2 (SHA-1) for an ECDSA signature. Only
* TLS 1.2 allows for other hash functions.
*/
int hash_id;
/**
* \brief Certificate chain to send to the server.
*
* This is an array of `br_x509_certificate` objects, each
* normally containing a DER-encoded certificate. The client
* code does not try to decode these elements. If there is no
* chain to send to the server, then this pointer shall be
* set to `NULL`.
*/
const br_x509_certificate *chain;
/**
* \brief Certificate chain length (number of certificates).
*
* If there is no chain to send to the server, then this value
* shall be set to 0.
*/
size_t chain_len;
} br_ssl_client_certificate;
/*
* Note: the constants below for signatures match the TLS constants.
*/
/** \brief Client authentication type: static ECDH. */
#define BR_AUTH_ECDH 0
/** \brief Client authentication type: RSA signature. */
#define BR_AUTH_RSA 1
/** \brief Client authentication type: ECDSA signature. */
#define BR_AUTH_ECDSA 3
/**
* \brief Class type for a certificate handler (client side).
*
* A certificate handler selects a client certificate chain to send to
* the server, upon explicit request from that server. It receives
* the list of trust anchor DN from the server, and supported types
* of certificates and signatures, and returns the chain to use. It
* is also invoked to perform the corresponding private key operation
* (a signature, or an ECDH computation).
*
* The SSL client engine will first push the trust anchor DN with
* `start_name_list()`, `start_name()`, `append_name()`, `end_name()`
* and `end_name_list()`. Then it will call `choose()`, to select the
* actual chain (and signature/hash algorithms). Finally, it will call
* either `do_sign()` or `do_keyx()`, depending on the algorithm choices.
*/
typedef struct br_ssl_client_certificate_class_ br_ssl_client_certificate_class;
struct br_ssl_client_certificate_class_ {
/**
* \brief Context size (in bytes).
*/
size_t context_size;
/**
* \brief Begin reception of a list of trust anchor names. This
* is called while parsing the incoming CertificateRequest.
*
* \param pctx certificate handler context.
*/
void (*start_name_list)(const br_ssl_client_certificate_class **pctx);
/**
* \brief Begin reception of a new trust anchor name.
*
* The total encoded name length is provided; it is less than
* 65535 bytes.
*
* \param pctx certificate handler context.
* \param len encoded name length (in bytes).
*/
void (*start_name)(const br_ssl_client_certificate_class **pctx,
size_t len);
/**
* \brief Receive some more bytes for the current trust anchor name.
*
* The provided reference (`data`) points to a transient buffer
* they may be reused as soon as this function returns. The chunk
* length (`len`) is never zero.
*
* \param pctx certificate handler context.
* \param data anchor name chunk.
* \param len anchor name chunk length (in bytes).
*/
void (*append_name)(const br_ssl_client_certificate_class **pctx,
const unsigned char *data, size_t len);
/**
* \brief End current trust anchor name.
*
* This function is called when all the encoded anchor name data
* has been provided.
*
* \param pctx certificate handler context.
*/
void (*end_name)(const br_ssl_client_certificate_class **pctx);
/**
* \brief End list of trust anchor names.
*
* This function is called when all the anchor names in the
* CertificateRequest message have been obtained.
*
* \param pctx certificate handler context.
*/
void (*end_name_list)(const br_ssl_client_certificate_class **pctx);
/**
* \brief Select client certificate and algorithms.
*
* This callback function shall fill the provided `choices`
* structure with the selected algorithms and certificate chain.
* The `hash_id`, `chain` and `chain_len` fields must be set. If
* the client cannot or does not wish to send a certificate,
* then it shall set `chain` to `NULL` and `chain_len` to 0.
*
* The `auth_types` parameter describes the authentication types,
* signature algorithms and hash functions that are supported by
* both the client context and the server, and compatible with
* the current protocol version. This is a bit field with the
* following contents:
*
* - If RSA signatures with hash function x are supported, then
* bit x is set.
*
* - If ECDSA signatures with hash function x are supported,
* then bit 8+x is set.
*
* - If static ECDH is supported, with a RSA-signed certificate,
* then bit 16 is set.
*
* - If static ECDH is supported, with an ECDSA-signed certificate,
* then bit 17 is set.
*
* Notes:
*
* - When using TLS 1.0 or 1.1, the hash function for RSA
* signatures is always the special MD5+SHA-1 (id 0), and the
* hash function for ECDSA signatures is always SHA-1 (id 2).
*
* - When using TLS 1.2, the list of hash functions is trimmed
* down to include only hash functions that the client context
* can support. The actual server list can be obtained with
* `br_ssl_client_get_server_hashes()`; that list may be used
* to select the certificate chain to send to the server.
*
* \param pctx certificate handler context.
* \param cc SSL client context.
* \param auth_types supported authentication types and algorithms.
* \param choices destination structure for the policy choices.
*/
void (*choose)(const br_ssl_client_certificate_class **pctx,
const br_ssl_client_context *cc, uint32_t auth_types,
br_ssl_client_certificate *choices);
/**
* \brief Perform key exchange (client part).
*
* This callback is invoked in case of a full static ECDH key
* exchange:
*
* - the cipher suite uses `ECDH_RSA` or `ECDH_ECDSA`;
*
* - the server requests a client certificate;
*
* - the client has, and sends, a client certificate that
* uses an EC key in the same curve as the server's key,
* and chooses static ECDH (the `hash_id` field in the choice
* structure was set to -1).
*
* In that situation, this callback is invoked to compute the
* client-side ECDH: the provided `data` (of length `*len` bytes)
* is the server's public key point (as decoded from its
* certificate), and the client shall multiply that point with
* its own private key, and write back the X coordinate of the
* resulting point in the same buffer, starting at offset 0.
* The `*len` value shall be modified to designate the actual
* length of the X coordinate.
*
* The callback must uphold the following:
*
* - If the input array does not have the proper length for
* an encoded curve point, then an error (0) shall be reported.
*
* - If the input array has the proper length, then processing
* MUST be constant-time, even if the data is not a valid
* encoded point.
*
* - This callback MUST check that the input point is valid.
*
* Returned value is 1 on success, 0 on error.
*
* \param pctx certificate handler context.
* \param data server public key point.
* \param len public key point length / X coordinate length.
* \return 1 on success, 0 on error.
*/
uint32_t (*do_keyx)(const br_ssl_client_certificate_class **pctx,
unsigned char *data, size_t *len);
/**
* \brief Perform a signature (client authentication).
*
* This callback is invoked when a client certificate was sent,
* and static ECDH is not used. It shall compute a signature,
* using the client's private key, over the provided hash value
* (which is the hash of all previous handshake messages).
*
* On input, the hash value to sign is in `data`, of size
* `hv_len`; the involved hash function is identified by
* `hash_id`. The signature shall be computed and written
* back into `data`; the total size of that buffer is `len`
* bytes.
*
* This callback shall verify that the signature length does not
* exceed `len` bytes, and abstain from writing the signature if
* it does not fit.
*
* For RSA signatures, the `hash_id` may be 0, in which case
* this is the special header-less signature specified in TLS 1.0
* and 1.1, with a 36-byte hash value. Otherwise, normal PKCS#1
* v1.5 signatures shall be computed.
*
* For ECDSA signatures, the signature value shall use the ASN.1
* based encoding.
*
* Returned value is the signature length (in bytes), or 0 on error.
*
* \param pctx certificate handler context.
* \param hash_id hash function identifier.
* \param hv_len hash value length (in bytes).
* \param data input/output buffer (hash value, then signature).
* \param len total buffer length (in bytes).
* \return signature length (in bytes) on success, or 0 on error.
*/
size_t (*do_sign)(const br_ssl_client_certificate_class **pctx,
int hash_id, size_t hv_len, unsigned char *data, size_t len);
};
/**
* \brief A single-chain RSA client certificate handler.
*
* This handler uses a single certificate chain, with a RSA
* signature. The list of trust anchor DN is ignored.
*
* Apart from the first field (vtable pointer), its contents are
* opaque and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_ssl_client_certificate_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
const br_x509_certificate *chain;
size_t chain_len;
const br_rsa_private_key *sk;
br_rsa_pkcs1_sign irsasign;
#endif
} br_ssl_client_certificate_rsa_context;
/**
* \brief A single-chain EC client certificate handler.
*
* This handler uses a single certificate chain, with a RSA
* signature. The list of trust anchor DN is ignored.
*
* This handler may support both static ECDH, and ECDSA signatures
* (either usage may be selectively disabled).
*
* Apart from the first field (vtable pointer), its contents are
* opaque and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_ssl_client_certificate_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
const br_x509_certificate *chain;
size_t chain_len;
const br_ec_private_key *sk;
unsigned allowed_usages;
unsigned issuer_key_type;
const br_multihash_context *mhash;
const br_ec_impl *iec;
br_ecdsa_sign iecdsa;
#endif
} br_ssl_client_certificate_ec_context;
/**
* \brief Context structure for a SSL client.
*
* The first field (called `eng`) is the SSL engine; all functions that
* work on a `br_ssl_engine_context` structure shall take as parameter
* a pointer to that field. The other structure fields are opaque and
* must not be accessed directly.
*/
struct br_ssl_client_context_ {
/**
* \brief The encapsulated engine context.
*/
br_ssl_engine_context eng;
#ifndef BR_DOXYGEN_IGNORE
/*
* Minimum ClientHello length; padding with an extension (RFC
* 7685) is added if necessary to match at least that length.
* Such padding is nominally unnecessary, but it has been used
* to work around some server implementation bugs.
*/
uint16_t min_clienthello_len;
/*
* Bit field for algoithms (hash + signature) supported by the
* server when requesting a client certificate.
*/
uint32_t hashes;
/*
* Server's public key curve.
*/
int server_curve;
/*
* Context for certificate handler.
*/
const br_ssl_client_certificate_class **client_auth_vtable;
/*
* Client authentication type.
*/
unsigned char auth_type;
/*
* Hash function to use for the client signature. This is 0xFF
* if static ECDH is used.
*/
unsigned char hash_id;
/*
* For the core certificate handlers, thus avoiding (in most
* cases) the need for an externally provided policy context.
*/
union {
const br_ssl_client_certificate_class *vtable;
br_ssl_client_certificate_rsa_context single_rsa;
br_ssl_client_certificate_ec_context single_ec;
} client_auth;
/*
* Implementations.
*/
br_rsa_public irsapub;
#endif
};
/**
* \brief Get the hash functions and signature algorithms supported by
* the server.
*
* This value is a bit field:
*
* - If RSA (PKCS#1 v1.5) is supported with hash function of ID `x`,
* then bit `x` is set (hash function ID is 0 for the special MD5+SHA-1,
* or 2 to 6 for the SHA family).
*
* - If ECDSA is supported with hash function of ID `x`, then bit `8+x`
* is set.
*
* - Newer algorithms are symbolic 16-bit identifiers that do not
* represent signature algorithm and hash function separately. If
* the TLS-level identifier is `0x0800+x` for a `x` in the 0..15
* range, then bit `16+x` is set.
*
* "New algorithms" are currently defined only in draft documents, so
* this support is subject to possible change. Right now (early 2017),
* this maps ed25519 (EdDSA on Curve25519) to bit 23, and ed448 (EdDSA
* on Curve448) to bit 24. If the identifiers on the wire change in
* future document, then the decoding mechanism in BearSSL will be
* amended to keep mapping ed25519 and ed448 on bits 23 and 24,
* respectively. Mapping of other new algorithms (e.g. RSA/PSS) is not
* guaranteed yet.
*
* \param cc client context.
* \return the server-supported hash functions and signature algorithms.
*/
static inline uint32_t
br_ssl_client_get_server_hashes(const br_ssl_client_context *cc)
{
return cc->hashes;
}
/**
* \brief Get the server key curve.
*
* This function returns the ID for the curve used by the server's public
* key. This is set when the server's certificate chain is processed;
* this value is 0 if the server's key is not an EC key.
*
* \return the server's public key curve ID, or 0.
*/
static inline int
br_ssl_client_get_server_curve(const br_ssl_client_context *cc)
{
return cc->server_curve;
}
/*
* Each br_ssl_client_init_xxx() function sets the list of supported
* cipher suites and used implementations, as specified by the profile
* name 'xxx'. Defined profile names are:
*
* full all supported versions and suites; constant-time implementations
* TODO: add other profiles
*/
/**
* \brief SSL client profile: full.
*
* This function initialises the provided SSL client context with
* all supported algorithms and cipher suites. It also initialises
* a companion X.509 validation engine with all supported algorithms,
* and the provided trust anchors; the X.509 engine will be used by
* the client context to validate the server's certificate.
*
* \param cc client context to initialise.
* \param xc X.509 validation context to initialise.
* \param trust_anchors trust anchors to use.
* \param trust_anchors_num number of trust anchors.
*/
void br_ssl_client_init_full(br_ssl_client_context *cc,
br_x509_minimal_context *xc,
const br_x509_trust_anchor *trust_anchors, size_t trust_anchors_num);
/**
* \brief Clear the complete contents of a SSL client context.
*
* Everything is cleared, including the reference to the configured buffer,
* implementations, cipher suites and state. This is a preparatory step
* to assembling a custom profile.
*
* \param cc client context to clear.
*/
void br_ssl_client_zero(br_ssl_client_context *cc);
/**
* \brief Set an externally provided client certificate handler context.
*
* The handler's methods are invoked when the server requests a client
* certificate.
*
* \param cc client context.
* \param pctx certificate handler context (pointer to its vtable field).
*/
static inline void
br_ssl_client_set_client_certificate(br_ssl_client_context *cc,
const br_ssl_client_certificate_class **pctx)
{
cc->client_auth_vtable = pctx;
}
/**
* \brief Set the RSA public-key operations implementation.
*
* This will be used to encrypt the pre-master secret with the server's
* RSA public key (RSA-encryption cipher suites only).
*
* \param cc client context.
* \param irsapub RSA public-key encryption implementation.
*/
static inline void
br_ssl_client_set_rsapub(br_ssl_client_context *cc, br_rsa_public irsapub)
{
cc->irsapub = irsapub;
}
/**
* \brief Set the "default" RSA implementation for public-key operations.
*
* This sets the RSA implementation in the client context (for encrypting
* the pre-master secret, in `TLS_RSA_*` cipher suites) to the fastest
* available on the current platform.
*
* \param cc client context.
*/
void br_ssl_client_set_default_rsapub(br_ssl_client_context *cc);
/**
* \brief Set the minimum ClientHello length (RFC 7685 padding).
*
* If this value is set and the ClientHello would be shorter, then
* the Pad ClientHello extension will be added with enough padding bytes
* to reach the target size. Because of the extension header, the resulting
* size will sometimes be slightly more than `len` bytes if the target
* size cannot be exactly met.
*
* The target length relates to the _contents_ of the ClientHello, not
* counting its 4-byte header. For instance, if `len` is set to 512,
* then the padding will bring the ClientHello size to 516 bytes with its
* header, and 521 bytes when counting the 5-byte record header.
*
* \param cc client context.
* \param len minimum ClientHello length (in bytes).
*/
static inline void
br_ssl_client_set_min_clienthello_len(br_ssl_client_context *cc, uint16_t len)
{
cc->min_clienthello_len = len;
}
/**
* \brief Prepare or reset a client context for a new connection.
*
* The `server_name` parameter is used to fill the SNI extension; the
* X.509 "minimal" engine will also match that name against the server
* names included in the server's certificate. If the parameter is
* `NULL` then no SNI extension will be sent, and the X.509 "minimal"
* engine (if used for server certificate validation) will not check
* presence of any specific name in the received certificate.
*
* Therefore, setting the `server_name` to `NULL` shall be reserved
* to cases where alternate or additional methods are used to ascertain
* that the right server public key is used (e.g. a "known key" model).
*
* If `resume_session` is non-zero and the context was previously used
* then the session parameters may be reused (depending on whether the
* server previously sent a non-empty session ID, and accepts the session
* resumption). The session parameters for session resumption can also
* be set explicitly with `br_ssl_engine_set_session_parameters()`.
*
* On failure, the context is marked as failed, and this function
* returns 0. A possible failure condition is when no initial entropy
* was injected, and none could be obtained from the OS (either OS
* randomness gathering is not supported, or it failed).
*
* \param cc client context.
* \param server_name target server name, or `NULL`.
* \param resume_session non-zero to try session resumption.
* \return 0 on failure, 1 on success.
*/
int br_ssl_client_reset(br_ssl_client_context *cc,
const char *server_name, int resume_session);
/**
* \brief Forget any session in the context.
*
* This means that the next handshake that uses this context will
* necessarily be a full handshake (this applies both to new connections
* and to renegotiations).
*
* \param cc client context.
*/
static inline void
br_ssl_client_forget_session(br_ssl_client_context *cc)
{
cc->eng.session.session_id_len = 0;
}
/**
* \brief Set client certificate chain and key (single RSA case).
*
* This function sets a client certificate chain, that the client will
* send to the server whenever a client certificate is requested. This
* certificate uses an RSA public key; the corresponding private key is
* invoked for authentication. Trust anchor names sent by the server are
* ignored.
*
* The provided chain and private key are linked in the client context;
* they must remain valid as long as they may be used, i.e. normally
* for the duration of the connection, since they might be invoked
* again upon renegotiations.
*
* \param cc SSL client context.
* \param chain client certificate chain (SSL order: EE comes first).
* \param chain_len client chain length (number of certificates).
* \param sk client private key.
* \param irsasign RSA signature implementation (PKCS#1 v1.5).
*/
void br_ssl_client_set_single_rsa(br_ssl_client_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk, br_rsa_pkcs1_sign irsasign);
/*
* \brief Set the client certificate chain and key (single EC case).
*
* This function sets a client certificate chain, that the client will
* send to the server whenever a client certificate is requested. This
* certificate uses an EC public key; the corresponding private key is
* invoked for authentication. Trust anchor names sent by the server are
* ignored.
*
* The provided chain and private key are linked in the client context;
* they must remain valid as long as they may be used, i.e. normally
* for the duration of the connection, since they might be invoked
* again upon renegotiations.
*
* The `allowed_usages` is a combination of usages, namely
* `BR_KEYTYPE_KEYX` and/or `BR_KEYTYPE_SIGN`. The `BR_KEYTYPE_KEYX`
* value allows full static ECDH, while the `BR_KEYTYPE_SIGN` value
* allows ECDSA signatures. If ECDSA signatures are used, then an ECDSA
* signature implementation must be provided; otherwise, the `iecdsa`
* parameter may be 0.
*
* The `cert_issuer_key_type` value is either `BR_KEYTYPE_RSA` or
* `BR_KEYTYPE_EC`; it is the type of the public key used the the CA
* that issued (signed) the client certificate. That value is used with
* full static ECDH: support of the certificate by the server depends
* on how the certificate was signed. (Note: when using TLS 1.2, this
* parameter is ignored; but its value matters for TLS 1.0 and 1.1.)
*
* \param cc server context.
* \param chain server certificate chain to send.
* \param chain_len chain length (number of certificates).
* \param sk server private key (EC).
* \param allowed_usages allowed private key usages.
* \param cert_issuer_key_type issuing CA's key type.
* \param iec EC core implementation.
* \param iecdsa ECDSA signature implementation ("asn1" format).
*/
void br_ssl_client_set_single_ec(br_ssl_client_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk, unsigned allowed_usages,
unsigned cert_issuer_key_type,
const br_ec_impl *iec, br_ecdsa_sign iecdsa);
/**
* \brief Type for a "translated cipher suite", as an array of two
* 16-bit integers.
*
* The first element is the cipher suite identifier (as used on the wire).
* The second element is the concatenation of four 4-bit elements which
* characterise the cipher suite contents. In most to least significant
* order, these 4-bit elements are:
*
* - Bits 12 to 15: key exchange + server key type
*
* | val | symbolic constant | suite type | details |
* | :-- | :----------------------- | :---------- | :----------------------------------------------- |
* | 0 | `BR_SSLKEYX_RSA` | RSA | RSA key exchange, key is RSA (encryption) |
* | 1 | `BR_SSLKEYX_ECDHE_RSA` | ECDHE_RSA | ECDHE key exchange, key is RSA (signature) |
* | 2 | `BR_SSLKEYX_ECDHE_ECDSA` | ECDHE_ECDSA | ECDHE key exchange, key is EC (signature) |
* | 3 | `BR_SSLKEYX_ECDH_RSA` | ECDH_RSA | Key is EC (key exchange), cert signed with RSA |
* | 4 | `BR_SSLKEYX_ECDH_ECDSA` | ECDH_ECDSA | Key is EC (key exchange), cert signed with ECDSA |
*
* - Bits 8 to 11: symmetric encryption algorithm
*
* | val | symbolic constant | symmetric encryption | key strength (bits) |
* | :-- | :--------------------- | :------------------- | :------------------ |
* | 0 | `BR_SSLENC_3DES_CBC` | 3DES/CBC | 168 |
* | 1 | `BR_SSLENC_AES128_CBC` | AES-128/CBC | 128 |
* | 2 | `BR_SSLENC_AES256_CBC` | AES-256/CBC | 256 |
* | 3 | `BR_SSLENC_AES128_GCM` | AES-128/GCM | 128 |
* | 4 | `BR_SSLENC_AES256_GCM` | AES-256/GCM | 256 |
* | 5 | `BR_SSLENC_CHACHA20` | ChaCha20/Poly1305 | 256 |
*
* - Bits 4 to 7: MAC algorithm
*
* | val | symbolic constant | MAC type | details |
* | :-- | :----------------- | :----------- | :------------------------------------ |
* | 0 | `BR_SSLMAC_AEAD` | AEAD | No dedicated MAC (encryption is AEAD) |
* | 2 | `BR_SSLMAC_SHA1` | HMAC/SHA-1 | Value matches `br_sha1_ID` |
* | 4 | `BR_SSLMAC_SHA256` | HMAC/SHA-256 | Value matches `br_sha256_ID` |
* | 5 | `BR_SSLMAC_SHA384` | HMAC/SHA-384 | Value matches `br_sha384_ID` |
*
* - Bits 0 to 3: hash function for PRF when used with TLS-1.2
*
* | val | symbolic constant | hash function | details |
* | :-- | :----------------- | :------------ | :----------------------------------- |
* | 4 | `BR_SSLPRF_SHA256` | SHA-256 | Value matches `br_sha256_ID` |
* | 5 | `BR_SSLPRF_SHA384` | SHA-384 | Value matches `br_sha384_ID` |
*
* For instance, cipher suite `TLS_RSA_WITH_AES_128_GCM_SHA256` has
* standard identifier 0x009C, and is translated to 0x0304, for, in
* that order: RSA key exchange (0), AES-128/GCM (3), AEAD integrity (0),
* SHA-256 in the TLS PRF (4).
*/
typedef uint16_t br_suite_translated[2];
#ifndef BR_DOXYGEN_IGNORE
/*
* Constants are already documented in the br_suite_translated type.
*/
#define BR_SSLKEYX_RSA 0
#define BR_SSLKEYX_ECDHE_RSA 1
#define BR_SSLKEYX_ECDHE_ECDSA 2
#define BR_SSLKEYX_ECDH_RSA 3
#define BR_SSLKEYX_ECDH_ECDSA 4
#define BR_SSLENC_3DES_CBC 0
#define BR_SSLENC_AES128_CBC 1
#define BR_SSLENC_AES256_CBC 2
#define BR_SSLENC_AES128_GCM 3
#define BR_SSLENC_AES256_GCM 4
#define BR_SSLENC_CHACHA20 5
#define BR_SSLMAC_AEAD 0
#define BR_SSLMAC_SHA1 br_sha1_ID
#define BR_SSLMAC_SHA256 br_sha256_ID
#define BR_SSLMAC_SHA384 br_sha384_ID
#define BR_SSLPRF_SHA256 br_sha256_ID
#define BR_SSLPRF_SHA384 br_sha384_ID
#endif
/*
* Pre-declaration for the SSL server context.
*/
typedef struct br_ssl_server_context_ br_ssl_server_context;
/**
* \brief Type for the server policy choices, taken after analysis of
* the client message (ClientHello).
*/
typedef struct {
/**
* \brief Cipher suite to use with that client.
*/
uint16_t cipher_suite;
/**
* \brief Hash function or algorithm for signing the ServerKeyExchange.
*
* This parameter is ignored for `TLS_RSA_*` and `TLS_ECDH_*`
* cipher suites; it is used only for `TLS_ECDHE_*` suites, in
* which the server _signs_ the ephemeral EC Diffie-Hellman
* parameters sent to the client.
*
* This identifier must be one of the following values:
*
* - `0xFF00 + id`, where `id` is a hash function identifier
* (0 for MD5+SHA-1, or 2 to 6 for one of the SHA functions);
*
* - a full 16-bit identifier, lower than `0xFF00`.
*
* If the first option is used, then the SSL engine will
* compute the hash of the data that is to be signed, with the
* designated hash function. The `do_sign()` method will be
* invoked with that hash value provided in the the `data`
* buffer.
*
* If the second option is used, then the SSL engine will NOT
* compute a hash on the data; instead, it will provide the
* to-be-signed data itself in `data`, i.e. the concatenation of
* the client random, server random, and encoded ECDH
* parameters. Furthermore, with TLS-1.2 and later, the 16-bit
* identifier will be used "as is" in the protocol, in the
* SignatureAndHashAlgorithm; for instance, `0x0401` stands for
* RSA PKCS#1 v1.5 signature (the `01`) with SHA-256 as hash
* function (the `04`).
*
* Take care that with TLS 1.0 and 1.1, the hash function is
* constrainted by the protocol: RSA signature must use
* MD5+SHA-1 (so use `0xFF00`), while ECDSA must use SHA-1
* (`0xFF02`). Since TLS 1.0 and 1.1 don't include a
* SignatureAndHashAlgorithm field in their ServerKeyExchange
* messages, any value below `0xFF00` will be usable to send the
* raw ServerKeyExchange data to the `do_sign()` callback, but
* that callback must still follow the protocol requirements
* when generating the signature.
*/
unsigned algo_id;
/**
* \brief Certificate chain to send to the client.
*
* This is an array of `br_x509_certificate` objects, each
* normally containing a DER-encoded certificate. The server
* code does not try to decode these elements.
*/
const br_x509_certificate *chain;
/**
* \brief Certificate chain length (number of certificates).
*/
size_t chain_len;
} br_ssl_server_choices;
/**
* \brief Class type for a policy handler (server side).
*
* A policy handler selects the policy parameters for a connection
* (cipher suite and other algorithms, and certificate chain to send to
* the client); it also performs the server-side computations involving
* its permanent private key.
*
* The SSL server engine will invoke first `choose()`, once the
* ClientHello message has been received, then either `do_keyx()`
* `do_sign()`, depending on the cipher suite.
*/
typedef struct br_ssl_server_policy_class_ br_ssl_server_policy_class;
struct br_ssl_server_policy_class_ {
/**
* \brief Context size (in bytes).
*/
size_t context_size;
/**
* \brief Select algorithms and certificates for this connection.
*
* This callback function shall fill the provided `choices`
* structure with the policy choices for this connection. This
* entails selecting the cipher suite, hash function for signing
* the ServerKeyExchange (applicable only to ECDHE cipher suites),
* and certificate chain to send.
*
* The callback receives a pointer to the server context that
* contains the relevant data. In particular, the functions
* `br_ssl_server_get_client_suites()`,
* `br_ssl_server_get_client_hashes()` and
* `br_ssl_server_get_client_curves()` can be used to obtain
* the cipher suites, hash functions and elliptic curves
* supported by both the client and server, respectively. The
* `br_ssl_engine_get_version()` and `br_ssl_engine_get_server_name()`
* functions yield the protocol version and requested server name
* (SNI), respectively.
*
* This function may modify its context structure (`pctx`) in
* arbitrary ways to keep track of its own choices.
*
* This function shall return 1 if appropriate policy choices
* could be made, or 0 if this connection cannot be pursued.
*
* \param pctx policy context.
* \param cc SSL server context.
* \param choices destination structure for the policy choices.
* \return 1 on success, 0 on error.
*/
int (*choose)(const br_ssl_server_policy_class **pctx,
const br_ssl_server_context *cc,
br_ssl_server_choices *choices);
/**
* \brief Perform key exchange (server part).
*
* This callback is invoked to perform the server-side cryptographic
* operation for a key exchange that is not ECDHE. This callback
* uses the private key.
*
* **For RSA key exchange**, the provided `data` (of length `*len`
* bytes) shall be decrypted with the server's private key, and
* the 48-byte premaster secret copied back to the first 48 bytes
* of `data`.
*
* - The caller makes sure that `*len` is at least 59 bytes.
*
* - This callback MUST check that the provided length matches
* that of the key modulus; it shall report an error otherwise.
*
* - If the length matches that of the RSA key modulus, then
* processing MUST be constant-time, even if decryption fails,
* or the padding is incorrect, or the plaintext message length
* is not exactly 48 bytes.
*
* - This callback needs not check the two first bytes of the
* obtained pre-master secret (the caller will do that).
*
* - If an error is reported (0), then what the callback put
* in the first 48 bytes of `data` is unimportant (the caller
* will use random bytes instead).
*
* **For ECDH key exchange**, the provided `data` (of length `*len`
* bytes) is the elliptic curve point from the client. The
* callback shall multiply it with its private key, and store
* the resulting X coordinate in `data`, starting at offset 0,
* and set `*len` to the length of the X coordinate.
*
* - If the input array does not have the proper length for
* an encoded curve point, then an error (0) shall be reported.
*
* - If the input array has the proper length, then processing
* MUST be constant-time, even if the data is not a valid
* encoded point.
*
* - This callback MUST check that the input point is valid.
*
* Returned value is 1 on success, 0 on error.
*
* \param pctx policy context.
* \param data key exchange data from the client.
* \param len key exchange data length (in bytes).
* \return 1 on success, 0 on error.
*/
uint32_t (*do_keyx)(const br_ssl_server_policy_class **pctx,
unsigned char *data, size_t *len);
/**
* \brief Perform a signature (for a ServerKeyExchange message).
*
* This callback function is invoked for ECDHE cipher suites. On
* input, the hash value or message to sign is in `data`, of
* size `hv_len`; the involved hash function or algorithm is
* identified by `algo_id`. The signature shall be computed and
* written back into `data`; the total size of that buffer is
* `len` bytes.
*
* This callback shall verify that the signature length does not
* exceed `len` bytes, and abstain from writing the signature if
* it does not fit.
*
* The `algo_id` value matches that which was written in the
* `choices` structures by the `choose()` callback. This will be
* one of the following:
*
* - `0xFF00 + id` for a hash function identifier `id`. In
* that case, the `data` buffer contains a hash value
* already computed over the data that is to be signed,
* of length `hv_len`. The `id` may be 0 to designate the
* special MD5+SHA-1 concatenation (old-style RSA signing).
*
* - Another value, lower than `0xFF00`. The `data` buffer
* then contains the raw, non-hashed data to be signed
* (concatenation of the client and server randoms and
* ECDH parameters). The callback is responsible to apply
* any relevant hashing as part of the signing process.
*
* Returned value is the signature length (in bytes), or 0 on error.
*
* \param pctx policy context.
* \param algo_id hash function / algorithm identifier.
* \param data input/output buffer (message/hash, then signature).
* \param hv_len hash value or message length (in bytes).
* \param len total buffer length (in bytes).
* \return signature length (in bytes) on success, or 0 on error.
*/
size_t (*do_sign)(const br_ssl_server_policy_class **pctx,
unsigned algo_id,
unsigned char *data, size_t hv_len, size_t len);
};
/**
* \brief A single-chain RSA policy handler.
*
* This policy context uses a single certificate chain, and a RSA
* private key. The context can be restricted to only signatures or
* only key exchange.
*
* Apart from the first field (vtable pointer), its contents are
* opaque and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_ssl_server_policy_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
const br_x509_certificate *chain;
size_t chain_len;
const br_rsa_private_key *sk;
unsigned allowed_usages;
br_rsa_private irsacore;
br_rsa_pkcs1_sign irsasign;
#endif
} br_ssl_server_policy_rsa_context;
/**
* \brief A single-chain EC policy handler.
*
* This policy context uses a single certificate chain, and an EC
* private key. The context can be restricted to only signatures or
* only key exchange.
*
* Due to how TLS is defined, this context must be made aware whether
* the server certificate was itself signed with RSA or ECDSA. The code
* does not try to decode the certificate to obtain that information.
*
* Apart from the first field (vtable pointer), its contents are
* opaque and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_ssl_server_policy_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
const br_x509_certificate *chain;
size_t chain_len;
const br_ec_private_key *sk;
unsigned allowed_usages;
unsigned cert_issuer_key_type;
const br_multihash_context *mhash;
const br_ec_impl *iec;
br_ecdsa_sign iecdsa;
#endif
} br_ssl_server_policy_ec_context;
/**
* \brief Class type for a session parameter cache.
*
* Session parameters are saved in the cache with `save()`, and
* retrieved with `load()`. The cache implementation can apply any
* storage and eviction strategy that it sees fit. The SSL server
* context that performs the request is provided, so that its
* functionalities may be used by the implementation (e.g. hash
* functions or random number generation).
*/
typedef struct br_ssl_session_cache_class_ br_ssl_session_cache_class;
struct br_ssl_session_cache_class_ {
/**
* \brief Context size (in bytes).
*/
size_t context_size;
/**
* \brief Record a session.
*
* This callback should record the provided session parameters.
* The `params` structure is transient, so its contents shall
* be copied into the cache. The session ID has been randomly
* generated and always has length exactly 32 bytes.
*
* \param ctx session cache context.
* \param server_ctx SSL server context.
* \param params session parameters to save.
*/
void (*save)(const br_ssl_session_cache_class **ctx,
br_ssl_server_context *server_ctx,
const br_ssl_session_parameters *params);
/**
* \brief Lookup a session in the cache.
*
* The session ID to lookup is in `params` and always has length
* exactly 32 bytes. If the session parameters are found in the
* cache, then the parameters shall be copied into the `params`
* structure. Returned value is 1 on successful lookup, 0
* otherwise.
*
* \param ctx session cache context.
* \param server_ctx SSL server context.
* \param params destination for session parameters.
* \return 1 if found, 0 otherwise.
*/
int (*load)(const br_ssl_session_cache_class **ctx,
br_ssl_server_context *server_ctx,
br_ssl_session_parameters *params);
};
/**
* \brief Context for a basic cache system.
*
* The system stores session parameters in a buffer provided at
* initialisation time. Each entry uses exactly 100 bytes, and
* buffer sizes up to 4294967295 bytes are supported.
*
* Entries are evicted with a LRU (Least Recently Used) policy. A
* search tree is maintained to keep lookups fast even with large
* caches.
*
* Apart from the first field (vtable pointer), the structure
* contents are opaque and shall not be accessed directly.
*/
typedef struct {
/** \brief Pointer to vtable. */
const br_ssl_session_cache_class *vtable;
#ifndef BR_DOXYGEN_IGNORE
unsigned char *store;
size_t store_len, store_ptr;
unsigned char index_key[32];
const br_hash_class *hash;
int init_done;
uint32_t head, tail, root;
#endif
} br_ssl_session_cache_lru;
/**
* \brief Initialise a LRU session cache with the provided storage space.
*
* The provided storage space must remain valid as long as the cache
* is used. Arbitrary lengths are supported, up to 4294967295 bytes;
* each entry uses up exactly 100 bytes.
*
* \param cc session cache context.
* \param store storage space for cached entries.
* \param store_len storage space length (in bytes).
*/
void br_ssl_session_cache_lru_init(br_ssl_session_cache_lru *cc,
unsigned char *store, size_t store_len);
/**
* \brief Forget an entry in an LRU session cache.
*
* The session cache context must have been initialised. The entry
* with the provided session ID (of exactly 32 bytes) is looked for
* in the cache; if located, it is disabled.
*
* \param cc session cache context.
* \param id session ID to forget.
*/
void br_ssl_session_cache_lru_forget(
br_ssl_session_cache_lru *cc, const unsigned char *id);
/**
* \brief Context structure for a SSL server.
*
* The first field (called `eng`) is the SSL engine; all functions that
* work on a `br_ssl_engine_context` structure shall take as parameter
* a pointer to that field. The other structure fields are opaque and
* must not be accessed directly.
*/
struct br_ssl_server_context_ {
/**
* \brief The encapsulated engine context.
*/
br_ssl_engine_context eng;
#ifndef BR_DOXYGEN_IGNORE
/*
* Maximum version from the client.
*/
uint16_t client_max_version;
/*
* Session cache.
*/
const br_ssl_session_cache_class **cache_vtable;
/*
* Translated cipher suites supported by the client. The list
* is trimmed to include only the cipher suites that the
* server also supports; they are in the same order as in the
* client message.
*/
br_suite_translated client_suites[BR_MAX_CIPHER_SUITES];
unsigned char client_suites_num;
/*
* Hash functions supported by the client, with ECDSA and RSA
* (bit mask). For hash function with id 'x', set bit index is
* x for RSA, x+8 for ECDSA. For newer algorithms, with ID
* 0x08**, bit 16+k is set for algorithm 0x0800+k.
*/
uint32_t hashes;
/*
* Curves supported by the client (bit mask, for named curves).
*/
uint32_t curves;
/*
* Context for chain handler.
*/
const br_ssl_server_policy_class **policy_vtable;
uint16_t sign_hash_id;
/*
* For the core handlers, thus avoiding (in most cases) the
* need for an externally provided policy context.
*/
union {
const br_ssl_server_policy_class *vtable;
br_ssl_server_policy_rsa_context single_rsa;
br_ssl_server_policy_ec_context single_ec;
} chain_handler;
/*
* Buffer for the ECDHE private key.
*/
unsigned char ecdhe_key[70];
size_t ecdhe_key_len;
/*
* Trust anchor names for client authentication. "ta_names" and
* "tas" cannot be both non-NULL.
*/
const br_x500_name *ta_names;
const br_x509_trust_anchor *tas;
size_t num_tas;
size_t cur_dn_index;
const unsigned char *cur_dn;
size_t cur_dn_len;
/*
* Buffer for the hash value computed over all handshake messages
* prior to CertificateVerify, and identifier for the hash function.
*/
unsigned char hash_CV[64];
size_t hash_CV_len;
int hash_CV_id;
/*
* Server-specific implementations.
* (none for now)
*/
#endif
};
/*
* Each br_ssl_server_init_xxx() function sets the list of supported
* cipher suites and used implementations, as specified by the profile
* name 'xxx'. Defined profile names are:
*
* full_rsa all supported algorithm, server key type is RSA
* full_ec all supported algorithm, server key type is EC
* TODO: add other profiles
*
* Naming scheme for "minimal" profiles: min123
*
* -- character 1: key exchange
* r = RSA
* e = ECDHE_RSA
* f = ECDHE_ECDSA
* u = ECDH_RSA
* v = ECDH_ECDSA
* -- character 2: version / PRF
* 0 = TLS 1.0 / 1.1 with MD5+SHA-1
* 2 = TLS 1.2 with SHA-256
* 3 = TLS 1.2 with SHA-384
* -- character 3: encryption
* a = AES/CBC
* d = 3DES/CBC
* g = AES/GCM
* c = ChaCha20+Poly1305
*/
/**
* \brief SSL server profile: full_rsa.
*
* This function initialises the provided SSL server context with
* all supported algorithms and cipher suites that rely on a RSA
* key pair.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk RSA private key.
*/
void br_ssl_server_init_full_rsa(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk);
/**
* \brief SSL server profile: full_ec.
*
* This function initialises the provided SSL server context with
* all supported algorithms and cipher suites that rely on an EC
* key pair.
*
* The key type of the CA that issued the server's certificate must
* be provided, since it matters for ECDH cipher suites (ECDH_RSA
* suites require a RSA-powered CA). The key type is either
* `BR_KEYTYPE_RSA` or `BR_KEYTYPE_EC`.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len chain length (number of certificates).
* \param cert_issuer_key_type certificate issuer's key type.
* \param sk EC private key.
*/
void br_ssl_server_init_full_ec(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
unsigned cert_issuer_key_type, const br_ec_private_key *sk);
/**
* \brief SSL server profile: minr2g.
*
* This profile uses only TLS_RSA_WITH_AES_128_GCM_SHA256. Server key is
* RSA, and RSA key exchange is used (not forward secure, but uses little
* CPU in the client).
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk RSA private key.
*/
void br_ssl_server_init_minr2g(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk);
/**
* \brief SSL server profile: mine2g.
*
* This profile uses only TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256. Server key
* is RSA, and ECDHE key exchange is used. This suite provides forward
* security, with a higher CPU expense on the client, and a somewhat
* larger code footprint (compared to "minr2g").
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk RSA private key.
*/
void br_ssl_server_init_mine2g(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk);
/**
* \brief SSL server profile: minf2g.
*
* This profile uses only TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256.
* Server key is EC, and ECDHE key exchange is used. This suite provides
* forward security, with a higher CPU expense on the client and server
* (by a factor of about 3 to 4), and a somewhat larger code footprint
* (compared to "minu2g" and "minv2g").
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk EC private key.
*/
void br_ssl_server_init_minf2g(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk);
/**
* \brief SSL server profile: minu2g.
*
* This profile uses only TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256.
* Server key is EC, and ECDH key exchange is used; the issuing CA used
* a RSA key.
*
* The "minu2g" and "minv2g" profiles do not provide forward secrecy,
* but are the lightest on the server (for CPU usage), and are rather
* inexpensive on the client as well.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk EC private key.
*/
void br_ssl_server_init_minu2g(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk);
/**
* \brief SSL server profile: minv2g.
*
* This profile uses only TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256.
* Server key is EC, and ECDH key exchange is used; the issuing CA used
* an EC key.
*
* The "minu2g" and "minv2g" profiles do not provide forward secrecy,
* but are the lightest on the server (for CPU usage), and are rather
* inexpensive on the client as well.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk EC private key.
*/
void br_ssl_server_init_minv2g(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk);
/**
* \brief SSL server profile: mine2c.
*
* This profile uses only TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256.
* Server key is RSA, and ECDHE key exchange is used. This suite
* provides forward security.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk RSA private key.
*/
void br_ssl_server_init_mine2c(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk);
/**
* \brief SSL server profile: minf2c.
*
* This profile uses only TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256.
* Server key is EC, and ECDHE key exchange is used. This suite provides
* forward security.
*
* \param cc server context to initialise.
* \param chain server certificate chain.
* \param chain_len certificate chain length (number of certificate).
* \param sk EC private key.
*/
void br_ssl_server_init_minf2c(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk);
/**
* \brief Get the supported client suites.
*
* This function shall be called only after the ClientHello has been
* processed, typically from the policy engine. The returned array
* contains the cipher suites that are supported by both the client
* and the server; these suites are in client preference order, unless
* the `BR_OPT_ENFORCE_SERVER_PREFERENCES` flag was set, in which case
* they are in server preference order.
*
* The suites are _translated_, which means that each suite is given
* as two 16-bit integers: the standard suite identifier, and its
* translated version, broken down into its individual components,
* as explained with the `br_suite_translated` type.
*
* The returned array is allocated in the context and will be rewritten
* by each handshake.
*
* \param cc server context.
* \param num receives the array size (number of suites).
* \return the translated common cipher suites, in preference order.
*/
static inline const br_suite_translated *
br_ssl_server_get_client_suites(const br_ssl_server_context *cc, size_t *num)
{
*num = cc->client_suites_num;
return cc->client_suites;
}
/**
* \brief Get the hash functions and signature algorithms supported by
* the client.
*
* This value is a bit field:
*
* - If RSA (PKCS#1 v1.5) is supported with hash function of ID `x`,
* then bit `x` is set (hash function ID is 0 for the special MD5+SHA-1,
* or 2 to 6 for the SHA family).
*
* - If ECDSA is supported with hash function of ID `x`, then bit `8+x`
* is set.
*
* - Newer algorithms are symbolic 16-bit identifiers that do not
* represent signature algorithm and hash function separately. If
* the TLS-level identifier is `0x0800+x` for a `x` in the 0..15
* range, then bit `16+x` is set.
*
* "New algorithms" are currently defined only in draft documents, so
* this support is subject to possible change. Right now (early 2017),
* this maps ed25519 (EdDSA on Curve25519) to bit 23, and ed448 (EdDSA
* on Curve448) to bit 24. If the identifiers on the wire change in
* future document, then the decoding mechanism in BearSSL will be
* amended to keep mapping ed25519 and ed448 on bits 23 and 24,
* respectively. Mapping of other new algorithms (e.g. RSA/PSS) is not
* guaranteed yet.
*
* \param cc server context.
* \return the client-supported hash functions and signature algorithms.
*/
static inline uint32_t
br_ssl_server_get_client_hashes(const br_ssl_server_context *cc)
{
return cc->hashes;
}
/**
* \brief Get the elliptic curves supported by the client.
*
* This is a bit field (bit x is set if curve of ID x is supported).
*
* \param cc server context.
* \return the client-supported elliptic curves.
*/
static inline uint32_t
br_ssl_server_get_client_curves(const br_ssl_server_context *cc)
{
return cc->curves;
}
/**
* \brief Clear the complete contents of a SSL server context.
*
* Everything is cleared, including the reference to the configured buffer,
* implementations, cipher suites and state. This is a preparatory step
* to assembling a custom profile.
*
* \param cc server context to clear.
*/
void br_ssl_server_zero(br_ssl_server_context *cc);
/**
* \brief Set an externally provided policy context.
*
* The policy context's methods are invoked to decide the cipher suite
* and certificate chain, and to perform operations involving the server's
* private key.
*
* \param cc server context.
* \param pctx policy context (pointer to its vtable field).
*/
static inline void
br_ssl_server_set_policy(br_ssl_server_context *cc,
const br_ssl_server_policy_class **pctx)
{
cc->policy_vtable = pctx;
}
/**
* \brief Set the server certificate chain and key (single RSA case).
*
* This function uses a policy context included in the server context.
* It configures use of a single server certificate chain with a RSA
* private key. The `allowed_usages` is a combination of usages, namely
* `BR_KEYTYPE_KEYX` and/or `BR_KEYTYPE_SIGN`; this enables or disables
* the corresponding cipher suites (i.e. `TLS_RSA_*` use the RSA key for
* key exchange, while `TLS_ECDHE_RSA_*` use the RSA key for signatures).
*
* \param cc server context.
* \param chain server certificate chain to send to the client.
* \param chain_len chain length (number of certificates).
* \param sk server private key (RSA).
* \param allowed_usages allowed private key usages.
* \param irsacore RSA core implementation.
* \param irsasign RSA signature implementation (PKCS#1 v1.5).
*/
void br_ssl_server_set_single_rsa(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_rsa_private_key *sk, unsigned allowed_usages,
br_rsa_private irsacore, br_rsa_pkcs1_sign irsasign);
/**
* \brief Set the server certificate chain and key (single EC case).
*
* This function uses a policy context included in the server context.
* It configures use of a single server certificate chain with an EC
* private key. The `allowed_usages` is a combination of usages, namely
* `BR_KEYTYPE_KEYX` and/or `BR_KEYTYPE_SIGN`; this enables or disables
* the corresponding cipher suites (i.e. `TLS_ECDH_*` use the EC key for
* key exchange, while `TLS_ECDHE_ECDSA_*` use the EC key for signatures).
*
* In order to support `TLS_ECDH_*` cipher suites (non-ephemeral ECDH),
* the algorithm type of the key used by the issuing CA to sign the
* server's certificate must be provided, as `cert_issuer_key_type`
* parameter (this value is either `BR_KEYTYPE_RSA` or `BR_KEYTYPE_EC`).
*
* \param cc server context.
* \param chain server certificate chain to send.
* \param chain_len chain length (number of certificates).
* \param sk server private key (EC).
* \param allowed_usages allowed private key usages.
* \param cert_issuer_key_type issuing CA's key type.
* \param iec EC core implementation.
* \param iecdsa ECDSA signature implementation ("asn1" format).
*/
void br_ssl_server_set_single_ec(br_ssl_server_context *cc,
const br_x509_certificate *chain, size_t chain_len,
const br_ec_private_key *sk, unsigned allowed_usages,
unsigned cert_issuer_key_type,
const br_ec_impl *iec, br_ecdsa_sign iecdsa);
/**
* \brief Activate client certificate authentication.
*
* The trust anchor encoded X.500 names (DN) to send to the client are
* provided. A client certificate will be requested and validated through
* the X.509 validator configured in the SSL engine. If `num` is 0, then
* client certificate authentication is disabled.
*
* If the client does not send a certificate, or on validation failure,
* the handshake aborts. Unauthenticated clients can be tolerated by
* setting the `BR_OPT_TOLERATE_NO_CLIENT_AUTH` flag.
*
* The provided array is linked in, not copied, so that pointer must
* remain valid as long as anchor names may be used.
*
* \param cc server context.
* \param ta_names encoded trust anchor names.
* \param num number of encoded trust anchor names.
*/
static inline void
br_ssl_server_set_trust_anchor_names(br_ssl_server_context *cc,
const br_x500_name *ta_names, size_t num)
{
cc->ta_names = ta_names;
cc->tas = NULL;
cc->num_tas = num;
}
/**
* \brief Activate client certificate authentication.
*
* This is a variant for `br_ssl_server_set_trust_anchor_names()`: the
* trust anchor names are provided not as an array of stand-alone names
* (`br_x500_name` structures), but as an array of trust anchors
* (`br_x509_trust_anchor` structures). The server engine itself will
* only use the `dn` field of each trust anchor. This is meant to allow
* defining a single array of trust anchors, to be used here and in the
* X.509 validation engine itself.
*
* The provided array is linked in, not copied, so that pointer must
* remain valid as long as anchor names may be used.
*
* \param cc server context.
* \param tas trust anchors (only names are used).
* \param num number of trust anchors.
*/
static inline void
br_ssl_server_set_trust_anchor_names_alt(br_ssl_server_context *cc,
const br_x509_trust_anchor *tas, size_t num)
{
cc->ta_names = NULL;
cc->tas = tas;
cc->num_tas = num;
}
/**
* \brief Configure the cache for session parameters.
*
* The cache context is provided as a pointer to its first field (vtable
* pointer).
*
* \param cc server context.
* \param vtable session cache context.
*/
static inline void
br_ssl_server_set_cache(br_ssl_server_context *cc,
const br_ssl_session_cache_class **vtable)
{
cc->cache_vtable = vtable;
}
/**
* \brief Prepare or reset a server context for handling an incoming client.
*
* \param cc server context.
* \return 1 on success, 0 on error.
*/
int br_ssl_server_reset(br_ssl_server_context *cc);
/* ===================================================================== */
/*
* Context for the simplified I/O context. The transport medium is accessed
* through the low_read() and low_write() callback functions, each with
* its own opaque context pointer.
*
* low_read() read some bytes, at most 'len' bytes, into data[]. The
* returned value is the number of read bytes, or -1 on error.
* The 'len' parameter is guaranteed never to exceed 20000,
* so the length always fits in an 'int' on all platforms.
*
* low_write() write up to 'len' bytes, to be read from data[]. The
* returned value is the number of written bytes, or -1 on
* error. The 'len' parameter is guaranteed never to exceed
* 20000, so the length always fits in an 'int' on all
* parameters.
*
* A socket closure (if the transport medium is a socket) should be reported
* as an error (-1). The callbacks shall endeavour to block until at least
* one byte can be read or written; a callback returning 0 at times is
* acceptable, but this normally leads to the callback being immediately
* called again, so the callback should at least always try to block for
* some time if no I/O can take place.
*
* The SSL engine naturally applies some buffering, so the callbacks need
* not apply buffers of their own.
*/
/**
* \brief Context structure for the simplified SSL I/O wrapper.
*
* This structure is initialised with `br_sslio_init()`. Its contents
* are opaque and shall not be accessed directly.
*/
typedef struct {
#ifndef BR_DOXYGEN_IGNORE
br_ssl_engine_context *engine;
int (*low_read)(void *read_context,
unsigned char *data, size_t len);
void *read_context;
int (*low_write)(void *write_context,
const unsigned char *data, size_t len);
void *write_context;
#endif
} br_sslio_context;
/**
* \brief Initialise a simplified I/O wrapper context.
*
* The simplified I/O wrapper offers a simpler read/write API for a SSL
* engine (client or server), using the provided callback functions for
* reading data from, or writing data to, the transport medium.
*
* The callback functions have the following semantics:
*
* - Each callback receives an opaque context value (of type `void *`)
* that the callback may use arbitrarily (or possibly ignore).
*
* - `low_read()` reads at least one byte, at most `len` bytes, from
* the transport medium. Read bytes shall be written in `data`.
*
* - `low_write()` writes at least one byte, at most `len` bytes, unto
* the transport medium. The bytes to write are read from `data`.
*
* - The `len` parameter is never zero, and is always lower than 20000.
*
* - The number of processed bytes (read or written) is returned. Since
* that number is less than 20000, it always fits on an `int`.
*
* - On error, the callbacks return -1. Reaching end-of-stream is an
* error. Errors are permanent: the SSL connection is terminated.
*
* - Callbacks SHOULD NOT return 0. This is tolerated, as long as
* callbacks endeavour to block for some non-negligible amount of
* time until at least one byte can be sent or received (if a
* callback returns 0, then the wrapper invokes it again
* immediately).
*
* - Callbacks MAY return as soon as at least one byte is processed;
* they MAY also insist on reading or writing _all_ requested bytes.
* Since SSL is a self-terminated protocol (each record has a length
* header), this does not change semantics.
*
* - Callbacks need not apply any buffering (for performance) since SSL
* itself uses buffers.
*
* \param ctx wrapper context to initialise.
* \param engine SSL engine to wrap.
* \param low_read callback for reading data from the transport.
* \param read_context context pointer for `low_read()`.
* \param low_write callback for writing data on the transport.
* \param write_context context pointer for `low_write()`.
*/
void br_sslio_init(br_sslio_context *ctx,
br_ssl_engine_context *engine,
int (*low_read)(void *read_context,
unsigned char *data, size_t len),
void *read_context,
int (*low_write)(void *write_context,
const unsigned char *data, size_t len),
void *write_context);
/**
* \brief Read some application data from a SSL connection.
*
* If `len` is zero, then this function returns 0 immediately. In
* all other cases, it never returns 0.
*
* This call returns only when at least one byte has been obtained.
* Returned value is the number of bytes read, or -1 on error. The
* number of bytes always fits on an 'int' (data from a single SSL/TLS
* record is returned).
*
* On error or SSL closure, this function returns -1. The caller should
* inspect the error status on the SSL engine to distinguish between
* normal closure and error.
*
* \param cc SSL wrapper context.
* \param dst destination buffer for application data.
* \param len maximum number of bytes to obtain.
* \return number of bytes obtained, or -1 on error.
*/
int br_sslio_read(br_sslio_context *cc, void *dst, size_t len);
/**
* \brief Read application data from a SSL connection.
*
* This calls returns only when _all_ requested `len` bytes are read,
* or an error is reached. Returned value is 0 on success, -1 on error.
* A normal (verified) SSL closure before that many bytes are obtained
* is reported as an error by this function.
*
* \param cc SSL wrapper context.
* \param dst destination buffer for application data.
* \param len number of bytes to obtain.
* \return 0 on success, or -1 on error.
*/
int br_sslio_read_all(br_sslio_context *cc, void *dst, size_t len);
/**
* \brief Write some application data unto a SSL connection.
*
* If `len` is zero, then this function returns 0 immediately. In
* all other cases, it never returns 0.
*
* This call returns only when at least one byte has been written.
* Returned value is the number of bytes written, or -1 on error. The
* number of bytes always fits on an 'int' (less than 20000).
*
* On error or SSL closure, this function returns -1. The caller should
* inspect the error status on the SSL engine to distinguish between
* normal closure and error.
*
* **Important:** SSL is buffered; a "written" byte is a byte that was
* injected into the wrapped SSL engine, but this does not necessarily mean
* that it has been scheduled for sending. Use `br_sslio_flush()` to
* ensure that all pending data has been sent to the transport medium.
*
* \param cc SSL wrapper context.
* \param src source buffer for application data.
* \param len maximum number of bytes to write.
* \return number of bytes written, or -1 on error.
*/
int br_sslio_write(br_sslio_context *cc, const void *src, size_t len);
/**
* \brief Write application data unto a SSL connection.
*
* This calls returns only when _all_ requested `len` bytes have been
* written, or an error is reached. Returned value is 0 on success, -1
* on error. A normal (verified) SSL closure before that many bytes are
* written is reported as an error by this function.
*
* **Important:** SSL is buffered; a "written" byte is a byte that was
* injected into the wrapped SSL engine, but this does not necessarily mean
* that it has been scheduled for sending. Use `br_sslio_flush()` to
* ensure that all pending data has been sent to the transport medium.
*
* \param cc SSL wrapper context.
* \param src source buffer for application data.
* \param len number of bytes to write.
* \return 0 on success, or -1 on error.
*/
int br_sslio_write_all(br_sslio_context *cc, const void *src, size_t len);
/**
* \brief Flush pending data.
*
* This call makes sure that any buffered application data in the
* provided context (including the wrapped SSL engine) has been sent
* to the transport medium (i.e. accepted by the `low_write()` callback
* method). If there is no such pending data, then this function does
* nothing (and returns a success, i.e. 0).
*
* If the underlying transport medium has its own buffers, then it is
* up to the caller to ensure the corresponding flushing.
*
* Returned value is 0 on success, -1 on error.
*
* \param cc SSL wrapper context.
* \return 0 on success, or -1 on error.
*/
int br_sslio_flush(br_sslio_context *cc);
/**
* \brief Close the SSL connection.
*
* This call runs the SSL closure protocol (sending a `close_notify`,
* receiving the response `close_notify`). When it returns, the SSL
* connection is finished. It is still up to the caller to manage the
* possible transport-level termination, if applicable (alternatively,
* the underlying transport stream may be reused for non-SSL messages).
*
* Returned value is 0 on success, -1 on error. A failure by the peer
* to process the complete closure protocol (i.e. sending back the
* `close_notify`) is an error.
*
* \param cc SSL wrapper context.
* \return 0 on success, or -1 on error.
*/
int br_sslio_close(br_sslio_context *cc);
/* ===================================================================== */
/*
* Symbolic constants for cipher suites.
*/
/* From RFC 5246 */
#define BR_TLS_NULL_WITH_NULL_NULL 0x0000
#define BR_TLS_RSA_WITH_NULL_MD5 0x0001
#define BR_TLS_RSA_WITH_NULL_SHA 0x0002
#define BR_TLS_RSA_WITH_NULL_SHA256 0x003B
#define BR_TLS_RSA_WITH_RC4_128_MD5 0x0004
#define BR_TLS_RSA_WITH_RC4_128_SHA 0x0005
#define BR_TLS_RSA_WITH_3DES_EDE_CBC_SHA 0x000A
#define BR_TLS_RSA_WITH_AES_128_CBC_SHA 0x002F
#define BR_TLS_RSA_WITH_AES_256_CBC_SHA 0x0035
#define BR_TLS_RSA_WITH_AES_128_CBC_SHA256 0x003C
#define BR_TLS_RSA_WITH_AES_256_CBC_SHA256 0x003D
#define BR_TLS_DH_DSS_WITH_3DES_EDE_CBC_SHA 0x000D
#define BR_TLS_DH_RSA_WITH_3DES_EDE_CBC_SHA 0x0010
#define BR_TLS_DHE_DSS_WITH_3DES_EDE_CBC_SHA 0x0013
#define BR_TLS_DHE_RSA_WITH_3DES_EDE_CBC_SHA 0x0016
#define BR_TLS_DH_DSS_WITH_AES_128_CBC_SHA 0x0030
#define BR_TLS_DH_RSA_WITH_AES_128_CBC_SHA 0x0031
#define BR_TLS_DHE_DSS_WITH_AES_128_CBC_SHA 0x0032
#define BR_TLS_DHE_RSA_WITH_AES_128_CBC_SHA 0x0033
#define BR_TLS_DH_DSS_WITH_AES_256_CBC_SHA 0x0036
#define BR_TLS_DH_RSA_WITH_AES_256_CBC_SHA 0x0037
#define BR_TLS_DHE_DSS_WITH_AES_256_CBC_SHA 0x0038
#define BR_TLS_DHE_RSA_WITH_AES_256_CBC_SHA 0x0039
#define BR_TLS_DH_DSS_WITH_AES_128_CBC_SHA256 0x003E
#define BR_TLS_DH_RSA_WITH_AES_128_CBC_SHA256 0x003F
#define BR_TLS_DHE_DSS_WITH_AES_128_CBC_SHA256 0x0040
#define BR_TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 0x0067
#define BR_TLS_DH_DSS_WITH_AES_256_CBC_SHA256 0x0068
#define BR_TLS_DH_RSA_WITH_AES_256_CBC_SHA256 0x0069
#define BR_TLS_DHE_DSS_WITH_AES_256_CBC_SHA256 0x006A
#define BR_TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 0x006B
#define BR_TLS_DH_anon_WITH_RC4_128_MD5 0x0018
#define BR_TLS_DH_anon_WITH_3DES_EDE_CBC_SHA 0x001B
#define BR_TLS_DH_anon_WITH_AES_128_CBC_SHA 0x0034
#define BR_TLS_DH_anon_WITH_AES_256_CBC_SHA 0x003A
#define BR_TLS_DH_anon_WITH_AES_128_CBC_SHA256 0x006C
#define BR_TLS_DH_anon_WITH_AES_256_CBC_SHA256 0x006D
/* From RFC 4492 */
#define BR_TLS_ECDH_ECDSA_WITH_NULL_SHA 0xC001
#define BR_TLS_ECDH_ECDSA_WITH_RC4_128_SHA 0xC002
#define BR_TLS_ECDH_ECDSA_WITH_3DES_EDE_CBC_SHA 0xC003
#define BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA 0xC004
#define BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA 0xC005
#define BR_TLS_ECDHE_ECDSA_WITH_NULL_SHA 0xC006
#define BR_TLS_ECDHE_ECDSA_WITH_RC4_128_SHA 0xC007
#define BR_TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA 0xC008
#define BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA 0xC009
#define BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA 0xC00A
#define BR_TLS_ECDH_RSA_WITH_NULL_SHA 0xC00B
#define BR_TLS_ECDH_RSA_WITH_RC4_128_SHA 0xC00C
#define BR_TLS_ECDH_RSA_WITH_3DES_EDE_CBC_SHA 0xC00D
#define BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA 0xC00E
#define BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA 0xC00F
#define BR_TLS_ECDHE_RSA_WITH_NULL_SHA 0xC010
#define BR_TLS_ECDHE_RSA_WITH_RC4_128_SHA 0xC011
#define BR_TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA 0xC012
#define BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA 0xC013
#define BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA 0xC014
#define BR_TLS_ECDH_anon_WITH_NULL_SHA 0xC015
#define BR_TLS_ECDH_anon_WITH_RC4_128_SHA 0xC016
#define BR_TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA 0xC017
#define BR_TLS_ECDH_anon_WITH_AES_128_CBC_SHA 0xC018
#define BR_TLS_ECDH_anon_WITH_AES_256_CBC_SHA 0xC019
/* From RFC 5288 */
#define BR_TLS_RSA_WITH_AES_128_GCM_SHA256 0x009C
#define BR_TLS_RSA_WITH_AES_256_GCM_SHA384 0x009D
#define BR_TLS_DHE_RSA_WITH_AES_128_GCM_SHA256 0x009E
#define BR_TLS_DHE_RSA_WITH_AES_256_GCM_SHA384 0x009F
#define BR_TLS_DH_RSA_WITH_AES_128_GCM_SHA256 0x00A0
#define BR_TLS_DH_RSA_WITH_AES_256_GCM_SHA384 0x00A1
#define BR_TLS_DHE_DSS_WITH_AES_128_GCM_SHA256 0x00A2
#define BR_TLS_DHE_DSS_WITH_AES_256_GCM_SHA384 0x00A3
#define BR_TLS_DH_DSS_WITH_AES_128_GCM_SHA256 0x00A4
#define BR_TLS_DH_DSS_WITH_AES_256_GCM_SHA384 0x00A5
#define BR_TLS_DH_anon_WITH_AES_128_GCM_SHA256 0x00A6
#define BR_TLS_DH_anon_WITH_AES_256_GCM_SHA384 0x00A7
/* From RFC 5289 */
#define BR_TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 0xC023
#define BR_TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384 0xC024
#define BR_TLS_ECDH_ECDSA_WITH_AES_128_CBC_SHA256 0xC025
#define BR_TLS_ECDH_ECDSA_WITH_AES_256_CBC_SHA384 0xC026
#define BR_TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 0xC027
#define BR_TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 0xC028
#define BR_TLS_ECDH_RSA_WITH_AES_128_CBC_SHA256 0xC029
#define BR_TLS_ECDH_RSA_WITH_AES_256_CBC_SHA384 0xC02A
#define BR_TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 0xC02B
#define BR_TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384 0xC02C
#define BR_TLS_ECDH_ECDSA_WITH_AES_128_GCM_SHA256 0xC02D
#define BR_TLS_ECDH_ECDSA_WITH_AES_256_GCM_SHA384 0xC02E
#define BR_TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 0xC02F
#define BR_TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 0xC030
#define BR_TLS_ECDH_RSA_WITH_AES_128_GCM_SHA256 0xC031
#define BR_TLS_ECDH_RSA_WITH_AES_256_GCM_SHA384 0xC032
/* From RFC 6655 and 7251 */
#define BR_TLS_RSA_WITH_AES_128_CCM 0xC09C
#define BR_TLS_RSA_WITH_AES_256_CCM 0xC09D
#define BR_TLS_RSA_WITH_AES_128_CCM_8 0xC0A0
#define BR_TLS_RSA_WITH_AES_256_CCM_8 0xC0A1
#define BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM 0xC0AC
#define BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM 0xC0AD
#define BR_TLS_ECDHE_ECDSA_WITH_AES_128_CCM_8 0xC0AE
#define BR_TLS_ECDHE_ECDSA_WITH_AES_256_CCM_8 0xC0AF
/* From RFC 7905 */
#define BR_TLS_ECDHE_RSA_WITH_CHACHA20_POLY1305_SHA256 0xCCA8
#define BR_TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256 0xCCA9
#define BR_TLS_DHE_RSA_WITH_CHACHA20_POLY1305_SHA256 0xCCAA
#define BR_TLS_PSK_WITH_CHACHA20_POLY1305_SHA256 0xCCAB
#define BR_TLS_ECDHE_PSK_WITH_CHACHA20_POLY1305_SHA256 0xCCAC
#define BR_TLS_DHE_PSK_WITH_CHACHA20_POLY1305_SHA256 0xCCAD
#define BR_TLS_RSA_PSK_WITH_CHACHA20_POLY1305_SHA256 0xCCAE
/* From RFC 7507 */
#define BR_TLS_FALLBACK_SCSV 0x5600
/*
* Symbolic constants for alerts.
*/
#define BR_ALERT_CLOSE_NOTIFY 0
#define BR_ALERT_UNEXPECTED_MESSAGE 10
#define BR_ALERT_BAD_RECORD_MAC 20
#define BR_ALERT_RECORD_OVERFLOW 22
#define BR_ALERT_DECOMPRESSION_FAILURE 30
#define BR_ALERT_HANDSHAKE_FAILURE 40
#define BR_ALERT_BAD_CERTIFICATE 42
#define BR_ALERT_UNSUPPORTED_CERTIFICATE 43
#define BR_ALERT_CERTIFICATE_REVOKED 44
#define BR_ALERT_CERTIFICATE_EXPIRED 45
#define BR_ALERT_CERTIFICATE_UNKNOWN 46
#define BR_ALERT_ILLEGAL_PARAMETER 47
#define BR_ALERT_UNKNOWN_CA 48
#define BR_ALERT_ACCESS_DENIED 49
#define BR_ALERT_DECODE_ERROR 50
#define BR_ALERT_DECRYPT_ERROR 51
#define BR_ALERT_PROTOCOL_VERSION 70
#define BR_ALERT_INSUFFICIENT_SECURITY 71
#define BR_ALERT_INTERNAL_ERROR 80
#define BR_ALERT_USER_CANCELED 90
#define BR_ALERT_NO_RENEGOTIATION 100
#define BR_ALERT_UNSUPPORTED_EXTENSION 110
#define BR_ALERT_NO_APPLICATION_PROTOCOL 120
#ifdef __cplusplus
}
#endif
#endif
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