/* * SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD * * SPDX-License-Identifier: Apache-2.0 */ #ifndef _ESP_TLS_H_ #define _ESP_TLS_H_ #include #include #include #include "esp_err.h" #include "esp_tls_errors.h" #ifdef CONFIG_ESP_TLS_USING_MBEDTLS #include "mbedtls/platform.h" #include "mbedtls/net_sockets.h" #include "mbedtls/esp_debug.h" #include "mbedtls/ssl.h" #include "mbedtls/entropy.h" #include "mbedtls/ctr_drbg.h" #include "mbedtls/error.h" #include "mbedtls/certs.h" #elif CONFIG_ESP_TLS_USING_WOLFSSL #include "wolfssl/wolfcrypt/settings.h" #include "wolfssl/ssl.h" #endif #ifdef __cplusplus extern "C" { #endif /** * @brief ESP-TLS Connection State */ typedef enum esp_tls_conn_state { ESP_TLS_INIT = 0, ESP_TLS_CONNECTING, ESP_TLS_HANDSHAKE, ESP_TLS_FAIL, ESP_TLS_DONE, } esp_tls_conn_state_t; typedef enum esp_tls_role { ESP_TLS_CLIENT = 0, ESP_TLS_SERVER, } esp_tls_role_t; /** * @brief ESP-TLS preshared key and hint structure */ typedef struct psk_key_hint { const uint8_t* key; /*!< key in PSK authentication mode in binary format */ const size_t key_size; /*!< length of the key */ const char* hint; /*!< hint in PSK authentication mode in string format */ } psk_hint_key_t; /** * @brief Keep alive parameters structure */ typedef struct tls_keep_alive_cfg { bool keep_alive_enable; /*!< Enable keep-alive timeout */ int keep_alive_idle; /*!< Keep-alive idle time (second) */ int keep_alive_interval; /*!< Keep-alive interval time (second) */ int keep_alive_count; /*!< Keep-alive packet retry send count */ } tls_keep_alive_cfg_t; /** * @brief ESP-TLS configuration parameters * * @note Note about format of certificates: * - This structure includes certificates of a Certificate Authority, of client or server as well * as private keys, which may be of PEM or DER format. In case of PEM format, the buffer must be * NULL terminated (with NULL character included in certificate size). * - Certificate Authority's certificate may be a chain of certificates in case of PEM format, * but could be only one certificate in case of DER format * - Variables names of certificates and private key buffers and sizes are defined as unions providing * backward compatibility for legacy *_pem_buf and *_pem_bytes names which suggested only PEM format * was supported. It is encouraged to use generic names such as cacert_buf and cacert_bytes. */ typedef struct esp_tls_cfg { const char **alpn_protos; /*!< Application protocols required for HTTP2. If HTTP2/ALPN support is required, a list of protocols that should be negotiated. The format is length followed by protocol name. For the most common cases the following is ok: const char **alpn_protos = { "h2", NULL }; - where 'h2' is the protocol name */ union { const unsigned char *cacert_buf; /*!< Certificate Authority's certificate in a buffer. Format may be PEM or DER, depending on mbedtls-support This buffer should be NULL terminated in case of PEM */ const unsigned char *cacert_pem_buf; /*!< CA certificate buffer legacy name */ }; union { unsigned int cacert_bytes; /*!< Size of Certificate Authority certificate pointed to by cacert_buf (including NULL-terminator in case of PEM format) */ unsigned int cacert_pem_bytes; /*!< Size of Certificate Authority certificate legacy name */ }; union { const unsigned char *clientcert_buf; /*!< Client certificate in a buffer Format may be PEM or DER, depending on mbedtls-support This buffer should be NULL terminated in case of PEM */ const unsigned char *clientcert_pem_buf; /*!< Client certificate legacy name */ }; union { unsigned int clientcert_bytes; /*!< Size of client certificate pointed to by clientcert_pem_buf (including NULL-terminator in case of PEM format) */ unsigned int clientcert_pem_bytes; /*!< Size of client certificate legacy name */ }; union { const unsigned char *clientkey_buf; /*!< Client key in a buffer Format may be PEM or DER, depending on mbedtls-support This buffer should be NULL terminated in case of PEM */ const unsigned char *clientkey_pem_buf; /*!< Client key legacy name */ }; union { unsigned int clientkey_bytes; /*!< Size of client key pointed to by clientkey_pem_buf (including NULL-terminator in case of PEM format) */ unsigned int clientkey_pem_bytes; /*!< Size of client key legacy name */ }; const unsigned char *clientkey_password;/*!< Client key decryption password string */ unsigned int clientkey_password_len; /*!< String length of the password pointed to by clientkey_password */ bool non_block; /*!< Configure non-blocking mode. If set to true the underneath socket will be configured in non blocking mode after tls session is established */ bool use_secure_element; /*!< Enable this option to use secure element or atecc608a chip ( Integrated with ESP32-WROOM-32SE ) */ int timeout_ms; /*!< Network timeout in milliseconds */ bool use_global_ca_store; /*!< Use a global ca_store for all the connections in which this bool is set. */ const char *common_name; /*!< If non-NULL, server certificate CN must match this name. If NULL, server certificate CN must match hostname. */ bool skip_common_name; /*!< Skip any validation of server certificate CN field */ tls_keep_alive_cfg_t *keep_alive_cfg; /*!< Enable TCP keep-alive timeout for SSL connection */ const psk_hint_key_t* psk_hint_key; /*!< Pointer to PSK hint and key. if not NULL (and certificates are NULL) then PSK authentication is enabled with configured setup. Important note: the pointer must be valid for connection */ esp_err_t (*crt_bundle_attach)(void *conf); /*!< Function pointer to esp_crt_bundle_attach. Enables the use of certification bundle for server verification, must be enabled in menuconfig */ void *ds_data; /*!< Pointer for digital signature peripheral context */ bool is_plain_tcp; /*!< Use non-TLS connection: When set to true, the esp-tls uses plain TCP transport rather then TLS/SSL connection. Note, that it is possible to connect using a plain tcp transport directly with esp_tls_plain_tcp_connect() API */ struct ifreq *if_name; /*!< The name of interface for data to go through. Use the default interface without setting */ } esp_tls_cfg_t; #ifdef CONFIG_ESP_TLS_SERVER typedef struct esp_tls_cfg_server { const char **alpn_protos; /*!< Application protocols required for HTTP2. If HTTP2/ALPN support is required, a list of protocols that should be negotiated. The format is length followed by protocol name. For the most common cases the following is ok: const char **alpn_protos = { "h2", NULL }; - where 'h2' is the protocol name */ union { const unsigned char *cacert_buf; /*!< Client CA certificate in a buffer. This buffer should be NULL terminated */ const unsigned char *cacert_pem_buf; /*!< Client CA certificate legacy name */ }; union { unsigned int cacert_bytes; /*!< Size of client CA certificate pointed to by cacert_pem_buf */ unsigned int cacert_pem_bytes; /*!< Size of client CA certificate legacy name */ }; union { const unsigned char *servercert_buf; /*!< Server certificate in a buffer This buffer should be NULL terminated */ const unsigned char *servercert_pem_buf; /*!< Server certificate legacy name */ }; union { unsigned int servercert_bytes; /*!< Size of server certificate pointed to by servercert_pem_buf */ unsigned int servercert_pem_bytes; /*!< Size of server certificate legacy name */ }; union { const unsigned char *serverkey_buf; /*!< Server key in a buffer This buffer should be NULL terminated */ const unsigned char *serverkey_pem_buf; /*!< Server key legacy name */ }; union { unsigned int serverkey_bytes; /*!< Size of server key pointed to by serverkey_pem_buf */ unsigned int serverkey_pem_bytes; /*!< Size of server key legacy name */ }; const unsigned char *serverkey_password; /*!< Server key decryption password string */ unsigned int serverkey_password_len; /*!< String length of the password pointed to by serverkey_password */ } esp_tls_cfg_server_t; #endif /* ! CONFIG_ESP_TLS_SERVER */ /** * @brief ESP-TLS Connection Handle */ typedef struct esp_tls { #ifdef CONFIG_ESP_TLS_USING_MBEDTLS mbedtls_ssl_context ssl; /*!< TLS/SSL context */ mbedtls_entropy_context entropy; /*!< mbedTLS entropy context structure */ mbedtls_ctr_drbg_context ctr_drbg; /*!< mbedTLS ctr drbg context structure. CTR_DRBG is deterministic random bit generation based on AES-256 */ mbedtls_ssl_config conf; /*!< TLS/SSL configuration to be shared between mbedtls_ssl_context structures */ mbedtls_net_context server_fd; /*!< mbedTLS wrapper type for sockets */ mbedtls_x509_crt cacert; /*!< Container for the X.509 CA certificate */ mbedtls_x509_crt *cacert_ptr; /*!< Pointer to the cacert being used. */ mbedtls_x509_crt clientcert; /*!< Container for the X.509 client certificate */ mbedtls_pk_context clientkey; /*!< Container for the private key of the client certificate */ #ifdef CONFIG_ESP_TLS_SERVER mbedtls_x509_crt servercert; /*!< Container for the X.509 server certificate */ mbedtls_pk_context serverkey; /*!< Container for the private key of the server certificate */ #endif #elif CONFIG_ESP_TLS_USING_WOLFSSL void *priv_ctx; void *priv_ssl; #endif int sockfd; /*!< Underlying socket file descriptor. */ ssize_t (*read)(struct esp_tls *tls, char *data, size_t datalen); /*!< Callback function for reading data from TLS/SSL connection. */ ssize_t (*write)(struct esp_tls *tls, const char *data, size_t datalen); /*!< Callback function for writing data to TLS/SSL connection. */ esp_tls_conn_state_t conn_state; /*!< ESP-TLS Connection state */ fd_set rset; /*!< read file descriptors */ fd_set wset; /*!< write file descriptors */ bool is_tls; /*!< indicates connection type (TLS or NON-TLS) */ esp_tls_role_t role; /*!< esp-tls role - ESP_TLS_CLIENT - ESP_TLS_SERVER */ esp_tls_error_handle_t error_handle; /*!< handle to error descriptor */ } esp_tls_t; /** * @brief Create TLS connection * * This function allocates and initializes esp-tls structure handle. * * @return tls Pointer to esp-tls as esp-tls handle if successfully initialized, * NULL if allocation error */ esp_tls_t *esp_tls_init(void); /** * @brief Create a new blocking TLS/SSL connection * * This function establishes a TLS/SSL connection with the specified host in blocking manner. * * Note: This API is present for backward compatibility reasons. Alternative function * with the same functionality is `esp_tls_conn_new_sync` (and its asynchronous version * `esp_tls_conn_new_async`) * * @param[in] hostname Hostname of the host. * @param[in] hostlen Length of hostname. * @param[in] port Port number of the host. * @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open * non-TLS connection, keep this NULL. For TLS connection, * a pass pointer to esp_tls_cfg_t. At a minimum, this * structure should be zero-initialized. * * @return pointer to esp_tls_t, or NULL if connection couldn't be opened. */ esp_tls_t *esp_tls_conn_new(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg) __attribute__ ((deprecated)); /** * @brief Create a new blocking TLS/SSL connection * * This function establishes a TLS/SSL connection with the specified host in blocking manner. * * @param[in] hostname Hostname of the host. * @param[in] hostlen Length of hostname. * @param[in] port Port number of the host. * @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open * non-TLS connection, keep this NULL. For TLS connection, * a pass pointer to esp_tls_cfg_t. At a minimum, this * structure should be zero-initialized. * @param[in] tls Pointer to esp-tls as esp-tls handle. * * @return * - -1 If connection establishment fails. * - 1 If connection establishment is successful. * - 0 If connection state is in progress. */ int esp_tls_conn_new_sync(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls); /** * @brief Create a new blocking TLS/SSL connection with a given "HTTP" url * * The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url. * * @param[in] url url of host. * @param[in] cfg TLS configuration as esp_tls_cfg_t. If you wish to open * non-TLS connection, keep this NULL. For TLS connection, * a pass pointer to 'esp_tls_cfg_t'. At a minimum, this * structure should be zero-initialized. * @return pointer to esp_tls_t, or NULL if connection couldn't be opened. */ esp_tls_t *esp_tls_conn_http_new(const char *url, const esp_tls_cfg_t *cfg); /** * @brief Create a new non-blocking TLS/SSL connection * * This function initiates a non-blocking TLS/SSL connection with the specified host, but due to * its non-blocking nature, it doesn't wait for the connection to get established. * * @param[in] hostname Hostname of the host. * @param[in] hostlen Length of hostname. * @param[in] port Port number of the host. * @param[in] cfg TLS configuration as esp_tls_cfg_t. `non_block` member of * this structure should be set to be true. * @param[in] tls pointer to esp-tls as esp-tls handle. * * @return * - -1 If connection establishment fails. * - 0 If connection establishment is in progress. * - 1 If connection establishment is successful. */ int esp_tls_conn_new_async(const char *hostname, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_t *tls); /** * @brief Create a new non-blocking TLS/SSL connection with a given "HTTP" url * * The behaviour is same as esp_tls_conn_new() API. However this API accepts host's url. * * @param[in] url url of host. * @param[in] cfg TLS configuration as esp_tls_cfg_t. * @param[in] tls pointer to esp-tls as esp-tls handle. * * @return * - -1 If connection establishment fails. * - 0 If connection establishment is in progress. * - 1 If connection establishment is successful. */ int esp_tls_conn_http_new_async(const char *url, const esp_tls_cfg_t *cfg, esp_tls_t *tls); /** * @brief Write from buffer 'data' into specified tls connection. * * @param[in] tls pointer to esp-tls as esp-tls handle. * @param[in] data Buffer from which data will be written. * @param[in] datalen Length of data buffer. * * @return * - >=0 if write operation was successful, the return value is the number * of bytes actually written to the TLS/SSL connection. * - <0 if write operation was not successful, because either an * error occured or an action must be taken by the calling process. */ static inline ssize_t esp_tls_conn_write(esp_tls_t *tls, const void *data, size_t datalen) { return tls->write(tls, (char *)data, datalen); } /** * @brief Read from specified tls connection into the buffer 'data'. * * @param[in] tls pointer to esp-tls as esp-tls handle. * @param[in] data Buffer to hold read data. * @param[in] datalen Length of data buffer. * * @return * - >0 if read operation was successful, the return value is the number * of bytes actually read from the TLS/SSL connection. * - 0 if read operation was not successful. The underlying * connection was closed. * - <0 if read operation was not successful, because either an * error occured or an action must be taken by the calling process. */ static inline ssize_t esp_tls_conn_read(esp_tls_t *tls, void *data, size_t datalen) { return tls->read(tls, (char *)data, datalen); } /** * @brief Compatible version of esp_tls_conn_destroy() to close the TLS/SSL connection * * @note This API will be removed in IDFv5.0 * * @param[in] tls pointer to esp-tls as esp-tls handle. */ void esp_tls_conn_delete(esp_tls_t *tls); /** * @brief Close the TLS/SSL connection and free any allocated resources. * * This function should be called to close each tls connection opened with esp_tls_conn_new() or * esp_tls_conn_http_new() APIs. * * @param[in] tls pointer to esp-tls as esp-tls handle. * * @return - 0 on success * - -1 if socket error or an invalid argument */ int esp_tls_conn_destroy(esp_tls_t *tls); /** * @brief Return the number of application data bytes remaining to be * read from the current record * * This API is a wrapper over mbedtls's mbedtls_ssl_get_bytes_avail() API. * * @param[in] tls pointer to esp-tls as esp-tls handle. * * @return * - -1 in case of invalid arg * - bytes available in the application data * record read buffer */ ssize_t esp_tls_get_bytes_avail(esp_tls_t *tls); /** * @brief Returns the connection socket file descriptor from esp_tls session * * @param[in] tls handle to esp_tls context * * @param[out] sockfd int pointer to sockfd value. * * @return - ESP_OK on success and value of sockfd will be updated with socket file descriptor for connection * - ESP_ERR_INVALID_ARG if (tls == NULL || sockfd == NULL) */ esp_err_t esp_tls_get_conn_sockfd(esp_tls_t *tls, int *sockfd); /** * @brief Create a global CA store, initially empty. * * This function should be called if the application wants to use the same CA store for multiple connections. * This function initialises the global CA store which can be then set by calling esp_tls_set_global_ca_store(). * To be effective, this function must be called before any call to esp_tls_set_global_ca_store(). * * @return * - ESP_OK if creating global CA store was successful. * - ESP_ERR_NO_MEM if an error occured when allocating the mbedTLS resources. */ esp_err_t esp_tls_init_global_ca_store(void); /** * @brief Set the global CA store with the buffer provided in pem format. * * This function should be called if the application wants to set the global CA store for * multiple connections i.e. to add the certificates in the provided buffer to the certificate chain. * This function implicitly calls esp_tls_init_global_ca_store() if it has not already been called. * The application must call this function before calling esp_tls_conn_new(). * * @param[in] cacert_pem_buf Buffer which has certificates in pem format. This buffer * is used for creating a global CA store, which can be used * by other tls connections. * @param[in] cacert_pem_bytes Length of the buffer. * * @return * - ESP_OK if adding certificates was successful. * - Other if an error occured or an action must be taken by the calling process. */ esp_err_t esp_tls_set_global_ca_store(const unsigned char *cacert_pem_buf, const unsigned int cacert_pem_bytes); /** * @brief Free the global CA store currently being used. * * The memory being used by the global CA store to store all the parsed certificates is * freed up. The application can call this API if it no longer needs the global CA store. */ void esp_tls_free_global_ca_store(void); /** * @brief Returns last error in esp_tls with detailed mbedtls related error codes. * The error information is cleared internally upon return * * @param[in] h esp-tls error handle. * @param[out] esp_tls_code last error code returned from mbedtls api (set to zero if none) * This pointer could be NULL if caller does not care about esp_tls_code * @param[out] esp_tls_flags last certification verification flags (set to zero if none) * This pointer could be NULL if caller does not care about esp_tls_code * * @return * - ESP_ERR_INVALID_STATE if invalid parameters * - ESP_OK (0) if no error occurred * - specific error code (based on ESP_ERR_ESP_TLS_BASE) otherwise */ esp_err_t esp_tls_get_and_clear_last_error(esp_tls_error_handle_t h, int *esp_tls_code, int *esp_tls_flags); /** * @brief Returns the last error captured in esp_tls of a specific type * The error information is cleared internally upon return * * @param[in] h esp-tls error handle. * @param[in] err_type specific error type * @param[out] error_code last error code returned from mbedtls api (set to zero if none) * This pointer could be NULL if caller does not care about esp_tls_code * @return * - ESP_ERR_INVALID_STATE if invalid parameters * - ESP_OK if a valid error returned and was cleared */ esp_err_t esp_tls_get_and_clear_error_type(esp_tls_error_handle_t h, esp_tls_error_type_t err_type, int *error_code); #if CONFIG_ESP_TLS_USING_MBEDTLS /** * @brief Get the pointer to the global CA store currently being used. * * The application must first call esp_tls_set_global_ca_store(). Then the same * CA store could be used by the application for APIs other than esp_tls. * * @note Modifying the pointer might cause a failure in verifying the certificates. * * @return * - Pointer to the global CA store currently being used if successful. * - NULL if there is no global CA store set. */ mbedtls_x509_crt *esp_tls_get_global_ca_store(void); #endif /* CONFIG_ESP_TLS_USING_MBEDTLS */ #ifdef CONFIG_ESP_TLS_SERVER /** * @brief Create TLS/SSL server session * * This function creates a TLS/SSL server context for already accepted client connection * and performs TLS/SSL handshake with the client * * @param[in] cfg Pointer to esp_tls_cfg_server_t * @param[in] sockfd FD of accepted connection * @param[out] tls Pointer to allocated esp_tls_t * * @return * - 0 if successful * - <0 in case of error * */ int esp_tls_server_session_create(esp_tls_cfg_server_t *cfg, int sockfd, esp_tls_t *tls); /** * @brief Close the server side TLS/SSL connection and free any allocated resources. * * This function should be called to close each tls connection opened with esp_tls_server_session_create() * * @param[in] tls pointer to esp_tls_t */ void esp_tls_server_session_delete(esp_tls_t *tls); #endif /* ! CONFIG_ESP_TLS_SERVER */ /** * @brief Creates a plain TCP connection, returning a valid socket fd on success or an error handle * * @param[in] host Hostname of the host. * @param[in] hostlen Length of hostname. * @param[in] port Port number of the host. * @param[in] cfg ESP-TLS configuration as esp_tls_cfg_t. * @param[out] error_handle ESP-TLS error handle holding potential errors occurred during connection * @param[out] sockfd Socket descriptor if successfully connected on TCP layer * @return ESP_OK on success * ESP_ERR_INVALID_ARG if invalid output parameters * ESP-TLS based error codes on failure */ esp_err_t esp_tls_plain_tcp_connect(const char *host, int hostlen, int port, const esp_tls_cfg_t *cfg, esp_tls_error_handle_t error_handle, int *sockfd); #ifdef __cplusplus } #endif #endif /* ! _ESP_TLS_H_ */