Currently, esp-tls supports creation of SSL/TLS connection on the client side. This commit includes support for creating SSL/TLS connection on the server side.
408 lines
18 KiB
C
408 lines
18 KiB
C
// Copyright 2017-2018 Espressif Systems (Shanghai) PTE LTD
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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#ifndef _ESP_TLS_H_
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#define _ESP_TLS_H_
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#include <stdbool.h>
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#include <sys/socket.h>
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#include <fcntl.h>
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#include "mbedtls/platform.h"
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#include "mbedtls/net_sockets.h"
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#include "mbedtls/esp_debug.h"
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#include "mbedtls/ssl.h"
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#include "mbedtls/entropy.h"
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#include "mbedtls/ctr_drbg.h"
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#include "mbedtls/error.h"
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#include "mbedtls/certs.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief ESP-TLS Connection State
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*/
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typedef enum esp_tls_conn_state {
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ESP_TLS_INIT = 0,
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ESP_TLS_CONNECTING,
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ESP_TLS_HANDSHAKE,
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ESP_TLS_FAIL,
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ESP_TLS_DONE,
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} esp_tls_conn_state_t;
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typedef enum esp_tls_role {
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ESP_TLS_CLIENT = 0,
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ESP_TLS_SERVER,
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} esp_tls_role_t;
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/**
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* @brief ESP-TLS configuration parameters
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*/
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typedef struct esp_tls_cfg {
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const char **alpn_protos; /*!< Application protocols required for HTTP2.
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If HTTP2/ALPN support is required, a list
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of protocols that should be negotiated.
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The format is length followed by protocol
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name.
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For the most common cases the following is ok:
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const char **alpn_protos = { "h2", NULL };
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- where 'h2' is the protocol name */
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const unsigned char *cacert_pem_buf; /*!< Certificate Authority's certificate in a buffer.
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This buffer should be NULL terminated */
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unsigned int cacert_pem_bytes; /*!< Size of Certificate Authority certificate
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pointed to by cacert_pem_buf */
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const unsigned char *clientcert_pem_buf;/*!< Client certificate in a buffer
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This buffer should be NULL terminated */
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unsigned int clientcert_pem_bytes; /*!< Size of client certificate pointed to by
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clientcert_pem_buf */
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const unsigned char *clientkey_pem_buf; /*!< Client key in a buffer
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This buffer should be NULL terminated */
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unsigned int clientkey_pem_bytes; /*!< Size of client key pointed to by
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clientkey_pem_buf */
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const unsigned char *clientkey_password;/*!< Client key decryption password string */
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unsigned int clientkey_password_len; /*!< String length of the password pointed to by
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clientkey_password */
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bool non_block; /*!< Configure non-blocking mode. If set to true the
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underneath socket will be configured in non
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blocking mode after tls session is established */
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int timeout_ms; /*!< Network timeout in milliseconds */
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bool use_global_ca_store; /*!< Use a global ca_store for all the connections in which
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this bool is set. */
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const char *common_name; /*!< If non-NULL, server certificate CN must match this name.
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If NULL, server certificate CN must match hostname. */
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bool skip_common_name; /*!< Skip any validation of server certificate CN field */
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} esp_tls_cfg_t;
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#ifdef CONFIG_ESP_TLS_SERVER
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typedef struct esp_tls_cfg_server {
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const char **alpn_protos; /*!< Application protocols required for HTTP2.
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If HTTP2/ALPN support is required, a list
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of protocols that should be negotiated.
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The format is length followed by protocol
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name.
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For the most common cases the following is ok:
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const char **alpn_protos = { "h2", NULL };
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- where 'h2' is the protocol name */
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const unsigned char *cacert_pem_buf; /*!< Client CA certificate in a buffer.
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This buffer should be NULL terminated */
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unsigned int cacert_pem_bytes; /*!< Size of client CA certificate
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pointed to by cacert_pem_buf */
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const unsigned char *servercert_pem_buf; /*!< Server certificate in a buffer
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This buffer should be NULL terminated */
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unsigned int servercert_pem_bytes; /*!< Size of server certificate pointed to by
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servercert_pem_buf */
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const unsigned char *serverkey_pem_buf; /*!< Server key in a buffer
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This buffer should be NULL terminated */
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unsigned int serverkey_pem_bytes; /*!< Size of server key pointed to by
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serverkey_pem_buf */
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const unsigned char *serverkey_password; /*!< Server key decryption password string */
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unsigned int serverkey_password_len; /*!< String length of the password pointed to by
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serverkey_password */
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} esp_tls_cfg_server_t;
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#endif /* ! CONFIG_ESP_TLS_SERVER */
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/**
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* @brief ESP-TLS Connection Handle
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*/
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typedef struct esp_tls {
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mbedtls_ssl_context ssl; /*!< TLS/SSL context */
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mbedtls_entropy_context entropy; /*!< mbedTLS entropy context structure */
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mbedtls_ctr_drbg_context ctr_drbg; /*!< mbedTLS ctr drbg context structure.
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CTR_DRBG is deterministic random
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bit generation based on AES-256 */
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mbedtls_ssl_config conf; /*!< TLS/SSL configuration to be shared
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between mbedtls_ssl_context
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structures */
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mbedtls_net_context server_fd; /*!< mbedTLS wrapper type for sockets */
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mbedtls_x509_crt cacert; /*!< Container for the X.509 CA certificate */
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mbedtls_x509_crt *cacert_ptr; /*!< Pointer to the cacert being used. */
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mbedtls_x509_crt clientcert; /*!< Container for the X.509 client certificate */
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mbedtls_pk_context clientkey; /*!< Container for the private key of the client
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certificate */
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#ifdef CONFIG_ESP_TLS_SERVER
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mbedtls_x509_crt servercert; /*!< Container for the X.509 server certificate */
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mbedtls_pk_context serverkey; /*!< Container for the private key of the server
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certificate */
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#endif
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int sockfd; /*!< Underlying socket file descriptor. */
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ssize_t (*read)(struct esp_tls *tls, char *data, size_t datalen); /*!< Callback function for reading data from TLS/SSL
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connection. */
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ssize_t (*write)(struct esp_tls *tls, const char *data, size_t datalen); /*!< Callback function for writing data to TLS/SSL
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connection. */
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esp_tls_conn_state_t conn_state; /*!< ESP-TLS Connection state */
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fd_set rset; /*!< read file descriptors */
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fd_set wset; /*!< write file descriptors */
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bool is_tls; /*!< indicates connection type (TLS or NON-TLS) */
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esp_tls_role_t role; /*!< esp-tls role
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- ESP_TLS_CLIENT
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- ESP_TLS_SERVER */
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} esp_tls_t;
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/**
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* @brief Create a new blocking TLS/SSL connection
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*
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* This function establishes a TLS/SSL connection with the specified host in blocking manner.
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*
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* @param[in] hostname Hostname of the host.
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* @param[in] hostlen Length of hostname.
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* @param[in] port Port number of the host.
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* @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open
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* non-TLS connection, keep this NULL. For TLS connection,
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* a pass pointer to esp_tls_cfg_t. At a minimum, this
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* structure should be zero-initialized.
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* @return pointer to esp_tls_t, or NULL if connection couldn't be opened.
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*/
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esp_tls_t *esp_tls_conn_new(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg);
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/**
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* @brief Create a new blocking TLS/SSL connection with a given "HTTP" url
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*
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* The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url.
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*
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* @param[in] url url of host.
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* @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open
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* non-TLS connection, keep this NULL. For TLS connection,
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* a pass pointer to 'esp_tls_cfg_t'. At a minimum, this
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* structure should be zero-initialized.
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* @return pointer to esp_tls_t, or NULL if connection couldn't be opened.
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*/
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esp_tls_t *esp_tls_conn_http_new(const char *url, const esp_tls_cfg_t *cfg);
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/**
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* @brief Create a new non-blocking TLS/SSL connection
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*
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* This function initiates a non-blocking TLS/SSL connection with the specified host, but due to
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* its non-blocking nature, it doesn't wait for the connection to get established.
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*
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* @param[in] hostname Hostname of the host.
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* @param[in] hostlen Length of hostname.
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* @param[in] port Port number of the host.
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* @param[in] cfg TLS configuration as esp_tls_cfg_t. `non_block` member of
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* this structure should be set to be true.
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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*
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* @return
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* - -1 If connection establishment fails.
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* - 0 If connection establishment is in progress.
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* - 1 If connection establishment is successful.
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*/
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int esp_tls_conn_new_async(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls);
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/**
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* @brief Create a new non-blocking TLS/SSL connection with a given "HTTP" url
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*
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* The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url.
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*
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* @param[in] url url of host.
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* @param[in] cfg TLS configuration as esp_tls_cfg_t.
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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*
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* @return
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* - -1 If connection establishment fails.
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* - 0 If connection establishment is in progress.
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* - 1 If connection establishment is successful.
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*/
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int esp_tls_conn_http_new_async(const char *url, const esp_tls_cfg_t *cfg, esp_tls_t *tls);
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/**
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* @brief Write from buffer 'data' into specified tls connection.
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*
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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* @param[in] data Buffer from which data will be written.
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* @param[in] datalen Length of data buffer.
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*
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* @return
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* - >0 if write operation was successful, the return value is the number
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* of bytes actually written to the TLS/SSL connection.
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* - 0 if write operation was not successful. The underlying
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* connection was closed.
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* - <0 if write operation was not successful, because either an
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* error occured or an action must be taken by the calling process.
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*/
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static inline ssize_t esp_tls_conn_write(esp_tls_t *tls, const void *data, size_t datalen)
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{
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return tls->write(tls, (char *)data, datalen);
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}
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/**
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* @brief Read from specified tls connection into the buffer 'data'.
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*
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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* @param[in] data Buffer to hold read data.
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* @param[in] datalen Length of data buffer.
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*
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* @return
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* - >0 if read operation was successful, the return value is the number
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* of bytes actually read from the TLS/SSL connection.
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* - 0 if read operation was not successful. The underlying
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* connection was closed.
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* - <0 if read operation was not successful, because either an
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* error occured or an action must be taken by the calling process.
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*/
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static inline ssize_t esp_tls_conn_read(esp_tls_t *tls, void *data, size_t datalen)
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{
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return tls->read(tls, (char *)data, datalen);
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}
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/**
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* @brief Close the TLS/SSL connection and free any allocated resources.
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*
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* This function should be called to close each tls connection opened with esp_tls_conn_new() or
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* esp_tls_conn_http_new() APIs.
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*
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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*/
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void esp_tls_conn_delete(esp_tls_t *tls);
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/**
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* @brief Return the number of application data bytes remaining to be
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* read from the current record
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*
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* This API is a wrapper over mbedtls's mbedtls_ssl_get_bytes_avail() API.
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*
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* @param[in] tls pointer to esp-tls as esp-tls handle.
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*
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* @return
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* - -1 in case of invalid arg
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* - bytes available in the application data
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* record read buffer
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*/
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size_t esp_tls_get_bytes_avail(esp_tls_t *tls);
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/**
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* @brief Create a global CA store, initially empty.
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*
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* This function should be called if the application wants to use the same CA store for multiple connections.
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* This function initialises the global CA store which can be then set by calling esp_tls_set_global_ca_store().
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* To be effective, this function must be called before any call to esp_tls_set_global_ca_store().
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*
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* @return
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* - ESP_OK if creating global CA store was successful.
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* - ESP_ERR_NO_MEM if an error occured when allocating the mbedTLS resources.
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*/
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esp_err_t esp_tls_init_global_ca_store();
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/**
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* @brief Set the global CA store with the buffer provided in pem format.
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*
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* This function should be called if the application wants to set the global CA store for
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* multiple connections i.e. to add the certificates in the provided buffer to the certificate chain.
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* This function implicitly calls esp_tls_init_global_ca_store() if it has not already been called.
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* The application must call this function before calling esp_tls_conn_new().
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*
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* @param[in] cacert_pem_buf Buffer which has certificates in pem format. This buffer
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* is used for creating a global CA store, which can be used
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* by other tls connections.
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* @param[in] cacert_pem_bytes Length of the buffer.
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*
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* @return
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* - ESP_OK if adding certificates was successful.
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* - Other if an error occured or an action must be taken by the calling process.
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*/
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esp_err_t esp_tls_set_global_ca_store(const unsigned char *cacert_pem_buf, const unsigned int cacert_pem_bytes);
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/**
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* @brief Get the pointer to the global CA store currently being used.
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*
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* The application must first call esp_tls_set_global_ca_store(). Then the same
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* CA store could be used by the application for APIs other than esp_tls.
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*
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* @note Modifying the pointer might cause a failure in verifying the certificates.
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*
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* @return
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* - Pointer to the global CA store currently being used if successful.
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* - NULL if there is no global CA store set.
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*/
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mbedtls_x509_crt *esp_tls_get_global_ca_store();
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/**
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* @brief Free the global CA store currently being used.
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*
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* The memory being used by the global CA store to store all the parsed certificates is
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* freed up. The application can call this API if it no longer needs the global CA store.
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*/
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void esp_tls_free_global_ca_store();
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#ifdef CONFIG_ESP_TLS_SERVER
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/**
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* @brief Create TLS/SSL server session
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*
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* This function creates a TLS/SSL server context for already accepted client connection
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* and performs TLS/SSL handshake with the client
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*
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* @param[in] cfg Pointer to esp_tls_cfg_server_t
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* @param[in] sockfd FD of accepted connection
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* @param[out] tls Pointer to allocated esp_tls_t
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*
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* @return
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* - 0 if successful
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* - <0 in case of error
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*
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*/
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int esp_tls_server_session_create(esp_tls_cfg_server_t *cfg, int sockfd, esp_tls_t *tls);
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/**
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* @brief Close the server side TLS/SSL connection and free any allocated resources.
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*
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* This function should be called to close each tls connection opened with esp_tls_server_session_create()
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*
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* @param[in] tls pointer to esp_tls_t
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*/
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void esp_tls_server_session_delete(esp_tls_t *tls);
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#endif /* ! CONFIG_ESP_TLS_SERVER */
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#ifdef __cplusplus
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}
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#endif
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#endif /* ! _ESP_TLS_H_ */
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