/*
* SPDX-FileCopyrightText: 2017-2021 Espressif Systems (Shanghai) CO LTD
*
* SPDX-License-Identifier: Apache-2.0
*/
#ifndef _ESP_TLS_H_
#define _ESP_TLS_H_
#include <stdbool.h>
#include <sys/socket.h>
#include <fcntl.h>
#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_ */