esp-idf/components/asio/port/mbedtls/include/mbedtls_engine.hpp

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//
// SPDX-FileCopyrightText: 2021-2022 Espressif Systems (Shanghai) CO LTD
//
// SPDX-License-Identifier: BSL-1.0
//
#pragma once
#include "mbedtls/ssl.h"
#include "mbedtls/entropy.h"
#include "mbedtls/ctr_drbg.h"
#include "mbedtls/error.h"
#include "mbedtls/esp_debug.h"
#include "esp_log.h"
namespace asio {
namespace ssl {
namespace mbedtls {
const char *error_message(int error_code)
{
static char error_buf[100];
mbedtls_strerror(error_code, error_buf, sizeof(error_buf));
return error_buf;
}
void throw_alloc_failure(const char* location)
{
asio::error_code ec( MBEDTLS_ERR_SSL_ALLOC_FAILED, asio::error::get_mbedtls_category());
asio::detail::throw_error(ec, location);
}
namespace error_codes {
bool is_error(int ret)
{
return ret < 0 && ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE;
}
static bool want_write(int ret)
{
return ret == MBEDTLS_ERR_SSL_WANT_WRITE;
}
static bool want_read(int ret)
{
return ret == MBEDTLS_ERR_SSL_WANT_READ;
}
} // namespace error_codes
enum rw_state {
IDLE, READING, WRITING, CLOSED
};
class engine {
public:
explicit engine(std::shared_ptr<context> ctx): ctx_(std::move(ctx)),
bio_(bio::new_pair("mbedtls-engine")), state_(IDLE), verify_mode_(0) {}
void set_verify_mode(asio::ssl::verify_mode mode)
{
verify_mode_ = mode;
}
bio* ext_bio() const
{
return bio_.second.get();
}
rw_state get_state() const
{
return state_;
}
int shutdown()
{
int ret = mbedtls_ssl_close_notify(&impl_.ssl_);
if (ret) {
impl::print_error("mbedtls_ssl_close_notify", ret);
}
state_ = CLOSED;
return ret;
}
int connect()
{
return handshake(true);
}
int accept()
{
return handshake(false);
}
int write(const void *buffer, int len)
{
int ret = impl_.write(buffer, len);
state_ = ret == len ? IDLE: WRITING;
return ret;
}
int read(void *buffer, int len)
{
int ret = impl_.read(buffer, len);
state_ = ret == len ? IDLE: READING;
return ret;
}
private:
int handshake(bool is_client_not_server)
{
if (impl_.before_handshake()) {
impl_.configure(ctx_.get(), is_client_not_server, impl_verify_mode(is_client_not_server));
}
return do_handshake();
}
static int bio_read(void *ctx, unsigned char *buf, size_t len)
{
auto bio = static_cast<BIO*>(ctx);
int read = bio->read(buf, len);
if (read <= 0 && bio->should_read()) {
return MBEDTLS_ERR_SSL_WANT_READ;
}
return read;
}
static int bio_write(void *ctx, const unsigned char *buf, size_t len)
{
auto bio = static_cast<BIO*>(ctx);
int written = bio->write(buf, len);
if (written <= 0 && bio->should_write()) {
return MBEDTLS_ERR_SSL_WANT_WRITE;
}
return written;
}
int do_handshake()
{
int ret = 0;
mbedtls_ssl_set_bio(&impl_.ssl_, bio_.first.get(), bio_write, bio_read, nullptr);
while (impl_.ssl_.MBEDTLS_PRIVATE(state) != MBEDTLS_SSL_HANDSHAKE_OVER) {
ret = mbedtls_ssl_handshake_step(&impl_.ssl_);
if (ret != 0) {
if (ret != MBEDTLS_ERR_SSL_WANT_READ && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
impl::print_error("mbedtls_ssl_handshake_step", ret);
}
if (ret == MBEDTLS_ERR_SSL_WANT_READ) {
state_ = READING;
} else if (ret == MBEDTLS_ERR_SSL_WANT_WRITE) {
state_ = WRITING;
}
break;
}
}
return ret;
}
// Converts OpenSSL verification mode to mbedtls enum
int impl_verify_mode(bool is_client_not_server) const
{
int mode = MBEDTLS_SSL_VERIFY_UNSET;
if (is_client_not_server) {
if (verify_mode_ & SSL_VERIFY_PEER)
mode = MBEDTLS_SSL_VERIFY_REQUIRED;
else if (verify_mode_ == SSL_VERIFY_NONE)
mode = MBEDTLS_SSL_VERIFY_NONE;
} else {
if (verify_mode_ & SSL_VERIFY_FAIL_IF_NO_PEER_CERT)
mode = MBEDTLS_SSL_VERIFY_REQUIRED;
else if (verify_mode_ & SSL_VERIFY_PEER)
mode = MBEDTLS_SSL_VERIFY_OPTIONAL;
else if (verify_mode_ == SSL_VERIFY_NONE)
mode = MBEDTLS_SSL_VERIFY_NONE;
}
return mode;
}
struct impl {
static void print_error(const char* function, int error_code)
{
constexpr const char *TAG="mbedtls-engine-impl";
ESP_LOGE(TAG, "%s() returned -0x%04X", function, -error_code);
ESP_LOGI(TAG, "-0x%04X: %s", -error_code, error_message(error_code));
}
bool before_handshake() const
{
return ssl_.MBEDTLS_PRIVATE(state) == 0;
}
int write(const void *buffer, int len)
{
int ret = mbedtls_ssl_write(&ssl_, static_cast<const unsigned char *>(buffer), len);
if (ret < 0 && ret != MBEDTLS_ERR_SSL_WANT_WRITE) {
print_error("mbedtls_ssl_write", ret);
}
return ret;
}
int read(void *buffer, int len)
{
int ret = mbedtls_ssl_read(&ssl_, static_cast<unsigned char *>(buffer), len);
if (ret < 0 && ret != MBEDTLS_ERR_SSL_WANT_READ) {
print_error("mbedtls_ssl_read", ret);
}
return ret;
}
impl()
{
const unsigned char pers[] = "asio ssl";
mbedtls_ssl_init(&ssl_);
mbedtls_ssl_config_init(&conf_);
mbedtls_ctr_drbg_init(&ctr_drbg_);
#ifdef CONFIG_MBEDTLS_DEBUG
mbedtls_esp_enable_debug_log(&conf_, CONFIG_MBEDTLS_DEBUG_LEVEL);
#endif
mbedtls_entropy_init(&entropy_);
mbedtls_ctr_drbg_seed(&ctr_drbg_, mbedtls_entropy_func, &entropy_, pers, sizeof(pers));
mbedtls_x509_crt_init(&public_cert_);
mbedtls_pk_init(&pk_key_);
mbedtls_x509_crt_init(&ca_cert_);
}
bool configure(context *ctx, bool is_client_not_server, int mbedtls_verify_mode)
{
mbedtls_x509_crt_init(&public_cert_);
mbedtls_pk_init(&pk_key_);
mbedtls_x509_crt_init(&ca_cert_);
int ret = mbedtls_ssl_config_defaults(&conf_, is_client_not_server ? MBEDTLS_SSL_IS_CLIENT: MBEDTLS_SSL_IS_SERVER,
MBEDTLS_SSL_TRANSPORT_STREAM, MBEDTLS_SSL_PRESET_DEFAULT);
if (ret) {
print_error("mbedtls_ssl_config_defaults", ret);
return false;
}
mbedtls_ssl_conf_rng(&conf_, mbedtls_ctr_drbg_random, &ctr_drbg_);
mbedtls_ssl_conf_authmode(&conf_, mbedtls_verify_mode);
if (ctx->cert_chain_.size() > 0 && ctx->private_key_.size() > 0) {
ret = mbedtls_x509_crt_parse(&public_cert_, ctx->data(container::CERT), ctx->size(container::CERT));
if (ret < 0) {
print_error("mbedtls_x509_crt_parse", ret);
return false;
}
ret = mbedtls_pk_parse_key(&pk_key_, ctx->data(container::PRIVKEY), ctx->size(container::PRIVKEY),
nullptr, 0, mbedtls_ctr_drbg_random, &ctr_drbg_);
if (ret < 0) {
print_error("mbedtls_pk_parse_keyfile", ret);
return false;
}
ret = mbedtls_ssl_conf_own_cert(&conf_, &public_cert_, &pk_key_);
if (ret) {
print_error("mbedtls_ssl_conf_own_cert", ret);
return false;
}
}
if (ctx->ca_cert_.size() > 0) {
ret = mbedtls_x509_crt_parse(&ca_cert_, ctx->data(container::CA_CERT), ctx->size(container::CA_CERT));
if (ret < 0) {
print_error("mbedtls_x509_crt_parse", ret);
return false;
}
mbedtls_ssl_conf_ca_chain(&conf_, &ca_cert_, nullptr);
} else {
mbedtls_ssl_conf_ca_chain(&conf_, nullptr, nullptr);
}
ret = mbedtls_ssl_setup(&ssl_, &conf_);
if (ret) {
print_error("mbedtls_ssl_setup", ret);
return false;
}
return true;
}
mbedtls_ssl_context ssl_{};
mbedtls_entropy_context entropy_{};
mbedtls_ctr_drbg_context ctr_drbg_{};
mbedtls_ssl_config conf_{};
mbedtls_x509_crt public_cert_{};
mbedtls_pk_context pk_key_{};
mbedtls_x509_crt ca_cert_{};
};
impl impl_{};
std::shared_ptr<context> ctx_;
std::pair<std::shared_ptr<bio>, std::shared_ptr<bio>> bio_;
enum rw_state state_;
asio::ssl::verify_mode verify_mode_;
};
} } } // namespace asio::ssl::mbedtls