/* * Copyright (c) 2007, Cameron Rich * * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions are met: * * * Redistributions of source code must retain the above copyright notice, * this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright notice, * this list of conditions and the following disclaimer in the documentation * and/or other materials provided with the distribution. * * Neither the name of the axTLS project nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ /** * @mainpage axTLS API * * @image html axolotl.jpg * * The axTLS library has features such as: * - The TLSv1 SSL client/server protocol * - No requirement to use any openssl libraries. * - A choice between AES block (128/256 bit) and RC4 (128 bit) stream ciphers. * - RSA encryption/decryption with variable sized keys (up to 4096 bits). * - Certificate chaining and peer authentication. * - Session resumption, session renegotiation. * - ASN.1, X.509, PKCS#8, PKCS#12 keys/certificates with DER/PEM encoding. * - Highly configurable compile time options. * - Portable across many platforms (written in ANSI C), and has language * bindings in C, C#, VB.NET, Java, Perl and Lua. * - Partial openssl API compatibility (via a wrapper). * - A very small footprint (around 50-60kB for the library in 'server-only' * mode). * - No dependencies on sockets - can use serial connections for example. * - A very simple API - ~ 20 functions/methods. * * A list of these functions/methods are described below. * * @ref c_api * * @ref bigint_api * * @ref csharp_api * * @ref java_api */ #ifndef HEADER_SSL_H #define HEADER_SSL_H #ifdef __cplusplus extern "C" { #endif #include /* need to predefine before ssl_lib.h gets to it */ #define SSL_SESSION_ID_SIZE 32 #include "tls1.h" /* The optional parameters that can be given to the client/server SSL engine */ #define SSL_CLIENT_AUTHENTICATION 0x00010000 #define SSL_SERVER_VERIFY_LATER 0x00020000 #define SSL_NO_DEFAULT_KEY 0x00040000 #define SSL_DISPLAY_STATES 0x00080000 #define SSL_DISPLAY_BYTES 0x00100000 #define SSL_DISPLAY_CERTS 0x00200000 #define SSL_DISPLAY_RSA 0x00400000 #define SSL_CONNECT_IN_PARTS 0x00800000 /* errors that can be generated */ #define SSL_OK 0 #define SSL_NOT_OK -1 #define SSL_ERROR_DEAD -2 #define SSL_CLOSE_NOTIFY -3 #define SSL_TIMEDOUT -4 #define SSL_ERROR_CONN_LOST -256 #define SSL_ERROR_SOCK_SETUP_FAILURE -258 #define SSL_ERROR_INVALID_HANDSHAKE -260 #define SSL_ERROR_INVALID_PROT_MSG -261 #define SSL_ERROR_INVALID_HMAC -262 #define SSL_ERROR_INVALID_VERSION -263 #define SSL_ERROR_INVALID_SESSION -265 #define SSL_ERROR_NO_CIPHER -266 #define SSL_ERROR_BAD_CERTIFICATE -268 #define SSL_ERROR_INVALID_KEY -269 #define SSL_ERROR_FINISHED_INVALID -271 #define SSL_ERROR_NO_CERT_DEFINED -272 #define SSL_ERROR_NO_CLIENT_RENOG -273 #define SSL_ERROR_NOT_SUPPORTED -274 #define SSL_X509_OFFSET -512 #define SSL_X509_ERROR(A) (SSL_X509_OFFSET+A) /* alert types that are recognized */ #define SSL_ALERT_TYPE_WARNING 1 #define SLL_ALERT_TYPE_FATAL 2 /* these are all the alerts that are recognized */ #define SSL_ALERT_CLOSE_NOTIFY 0 #define SSL_ALERT_UNEXPECTED_MESSAGE 10 #define SSL_ALERT_BAD_RECORD_MAC 20 #define SSL_ALERT_HANDSHAKE_FAILURE 40 #define SSL_ALERT_BAD_CERTIFICATE 42 #define SSL_ALERT_ILLEGAL_PARAMETER 47 #define SSL_ALERT_DECODE_ERROR 50 #define SSL_ALERT_DECRYPT_ERROR 51 #define SSL_ALERT_INVALID_VERSION 70 #define SSL_ALERT_NO_RENEGOTIATION 100 /* The ciphers that are supported */ #define SSL_AES128_SHA 0x2f #define SSL_AES256_SHA 0x35 #define SSL_RC4_128_SHA 0x05 #define SSL_RC4_128_MD5 0x04 /* build mode ids' */ #define SSL_BUILD_SKELETON_MODE 0x01 #define SSL_BUILD_SERVER_ONLY 0x02 #define SSL_BUILD_ENABLE_VERIFICATION 0x03 #define SSL_BUILD_ENABLE_CLIENT 0x04 #define SSL_BUILD_FULL_MODE 0x05 /* offsets to retrieve configuration information */ #define SSL_BUILD_MODE 0 #define SSL_MAX_CERT_CFG_OFFSET 1 #define SSL_MAX_CA_CERT_CFG_OFFSET 2 #define SSL_HAS_PEM 3 /* default session sizes */ #define SSL_DEFAULT_SVR_SESS 5 #define SSL_DEFAULT_CLNT_SESS 1 /* X.509/X.520 distinguished name types */ #define SSL_X509_CERT_COMMON_NAME 0 #define SSL_X509_CERT_ORGANIZATION 1 #define SSL_X509_CERT_ORGANIZATIONAL_NAME 2 #define SSL_X509_CA_CERT_COMMON_NAME 3 #define SSL_X509_CA_CERT_ORGANIZATION 4 #define SSL_X509_CA_CERT_ORGANIZATIONAL_NAME 5 /* SSL object loader types */ #define SSL_OBJ_X509_CERT 1 #define SSL_OBJ_X509_CACERT 2 #define SSL_OBJ_RSA_KEY 3 #define SSL_OBJ_PKCS8 4 #define SSL_OBJ_PKCS12 5 /** * @defgroup c_api Standard C API * @brief The standard interface in C. * @{ */ /** * @brief Establish a new client/server context. * * This function is called before any client/server SSL connections are made. * * Each new connection will use the this context's private key and * certificate chain. If a different certificate chain is required, then a * different context needs to be be used. * * There are two threading models supported - a single thread with one * SSL_CTX can support any number of SSL connections - and multiple threads can * support one SSL_CTX object each (the default). But if a single SSL_CTX * object uses many SSL objects in individual threads, then the * CONFIG_SSL_CTX_MUTEXING option needs to be configured. * * @param options [in] Any particular options. At present the options * supported are: * - SSL_SERVER_VERIFY_LATER (client only): Don't stop a handshake if the server * authentication fails. The certificate can be authenticated later with a * call to ssl_verify_cert(). * - SSL_CLIENT_AUTHENTICATION (server only): Enforce client authentication * i.e. each handshake will include a "certificate request" message from the * server. Only available if verification has been enabled. * - SSL_DISPLAY_BYTES (full mode build only): Display the byte sequences * during the handshake. * - SSL_DISPLAY_STATES (full mode build only): Display the state changes * during the handshake. * - SSL_DISPLAY_CERTS (full mode build only): Display the certificates that * are passed during a handshake. * - SSL_DISPLAY_RSA (full mode build only): Display the RSA key details that * are passed during a handshake. * - SSL_CONNECT_IN_PARTS (client only): To use a non-blocking version of * ssl_client_new(). * @param num_sessions [in] The number of sessions to be used for session * caching. If this value is 0, then there is no session caching. This option * is not used in skeleton mode. * @return A client/server context. */ EXP_FUNC SSL_CTX * STDCALL ssl_ctx_new(uint32_t options, int num_sessions); /** * @brief Remove a client/server context. * * Frees any used resources used by this context. Each connection will be * sent a "Close Notify" alert (if possible). * @param ssl_ctx [in] The client/server context. */ EXP_FUNC void STDCALL ssl_ctx_free(SSL_CTX *ssl_ctx); /** * @brief (server only) Establish a new SSL connection to an SSL client. * * It is up to the application to establish the logical connection (whether it * is a socket, serial connection etc). * @param ssl_ctx [in] The server context. * @param client_fd [in] The client's file descriptor. * @return An SSL object reference. */ EXP_FUNC SSL * STDCALL ssl_server_new(SSL_CTX *ssl_ctx, int client_fd); /** * @brief (client only) Establish a new SSL connection to an SSL server. * * It is up to the application to establish the initial logical connection * (whether it is a socket, serial connection etc). * * This is a normally a blocking call - it will finish when the handshake is * complete (or has failed). To use in non-blocking mode, set * SSL_CONNECT_IN_PARTS in ssl_ctx_new(). * @param ssl_ctx [in] The client context. * @param client_fd [in] The client's file descriptor. * @param session_id [in] A 32 byte session id for session resumption. This * can be null if no session resumption is being used or required. This option * is not used in skeleton mode. * @param sess_id_size The size of the session id (max 32) * @return An SSL object reference. Use ssl_handshake_status() to check * if a handshake succeeded. */ EXP_FUNC SSL * STDCALL ssl_client_new(SSL_CTX *ssl_ctx, int client_fd, const uint8_t *session_id, uint8_t sess_id_size); /** * @brief Free any used resources on this connection. * A "Close Notify" message is sent on this connection (if possible). It is up * to the application to close the socket or file descriptor. * @param ssl [in] The ssl object reference. */ EXP_FUNC void STDCALL ssl_free(SSL *ssl); /** * @brief Read the SSL data stream. * If the socket is non-blocking and data is blocked then SSO_OK will be * returned. * @param ssl [in] An SSL object reference. * @param in_data [out] If the read was successful, a pointer to the read * buffer will be here. Do NOT ever free this memory as this buffer is used in * sucessive calls. If the call was unsuccessful, this value will be null. * @return The number of decrypted bytes: * - if > 0, then the handshaking is complete and we are returning the number * of decrypted bytes. * - SSL_OK if the handshaking stage is successful (but not yet complete). * - < 0 if an error. * @see ssl.h for the error code list. * @note Use in_data before doing any successive ssl calls. */ EXP_FUNC int STDCALL ssl_read(SSL *ssl, uint8_t **in_data); /* Synchronous internal version of above used for protocol negotiation */ EXP_FUNC int STDCALL ssl_readi(SSL *ssl, uint8_t **in_data); /** * @brief Write to the SSL data stream. * if the socket is non-blocking and data is blocked then a check is made * to ensure that all data is sent (i.e. blocked mode is forced). * @param ssl [in] An SSL obect reference. * @param out_data [in] The data to be written * @param out_len [in] The number of bytes to be written. * @return The number of bytes sent, or if < 0 if an error. * @see ssl.h for the error code list. */ EXP_FUNC int STDCALL ssl_write(SSL *ssl, const uint8_t *out_data, int out_len); /** * @brief Find an ssl object based on a file descriptor. * * Goes through the list of SSL objects maintained in a client/server context * to look for a file descriptor match. * @param ssl_ctx [in] The client/server context. * @param client_fd [in] The file descriptor. * @return A reference to the SSL object. Returns null if the object could not * be found. */ EXP_FUNC SSL * STDCALL ssl_find(SSL_CTX *ssl_ctx, int client_fd); /** * @brief Get the session id for a handshake. * * This will be a 32 byte sequence and is available after the first * handshaking messages are sent. * @param ssl [in] An SSL object reference. * @return The session id as a 32 byte sequence. * @note A SSLv23 handshake may have only 16 valid bytes. */ EXP_FUNC const uint8_t * STDCALL ssl_get_session_id(const SSL *ssl); /** * @brief Get the session id size for a handshake. * * This will normally be 32 but could be 0 (no session id) or something else. * @param ssl [in] An SSL object reference. * @return The size of the session id. */ EXP_FUNC uint8_t STDCALL ssl_get_session_id_size(const SSL *ssl); /** * @brief Return the cipher id (in the SSL form). * @param ssl [in] An SSL object reference. * @return The cipher id. This will be one of the following: * - SSL_AES128_SHA (0x2f) * - SSL_AES256_SHA (0x35) * - SSL_RC4_128_SHA (0x05) * - SSL_RC4_128_MD5 (0x04) */ EXP_FUNC uint8_t STDCALL ssl_get_cipher_id(const SSL *ssl); /** * @brief Return the status of the handshake. * @param ssl [in] An SSL object reference. * @return SSL_OK if the handshake is complete and ok. * @see ssl.h for the error code list. */ EXP_FUNC int STDCALL ssl_handshake_status(const SSL *ssl); /** * @brief Retrieve various parameters about the axTLS engine. * @param offset [in] The configuration offset. It will be one of the following: * - SSL_BUILD_MODE The build mode. This will be one of the following: * - SSL_BUILD_SERVER_ONLY (basic server mode) * - SSL_BUILD_ENABLE_VERIFICATION (server can do client authentication) * - SSL_BUILD_ENABLE_CLIENT (client/server capabilties) * - SSL_BUILD_FULL_MODE (client/server with diagnostics) * - SSL_BUILD_SKELETON_MODE (skeleton mode) * - SSL_MAX_CERT_CFG_OFFSET The maximum number of certificates allowed. * - SSL_MAX_CA_CERT_CFG_OFFSET The maximum number of CA certificates allowed. * - SSL_HAS_PEM 1 if supported * @return The value of the requested parameter. */ EXP_FUNC int STDCALL ssl_get_config(int offset); /** * @brief Return a string explaining why the handshake failed. * * This call is can be used by diagnostics elsewhere. * @param error_code [in] An error code. * @return The appropriate string, which may be static. * @see ssl.h for the error code list. */ EXP_FUNC const char * STDCALL ssl_error_string(int error_code); /** * @brief Display why the handshake failed. * * This call is only useful in a 'full mode' build. The output is to stdout. * @param error_code [in] An error code. * @see ssl.h for the error code list. */ EXP_FUNC void STDCALL ssl_display_error(int error_code); /** * @brief Authenticate a received certificate. * * This call is usually made by a client after a handshake is complete and the * context is in SSL_SERVER_VERIFY_LATER mode. * @param ssl [in] An SSL object reference. * @return SSL_OK if the certificate is verified. */ EXP_FUNC int STDCALL ssl_verify_cert(const SSL *ssl); /** * @brief Retrieve an X.509 distinguished name component. * * When a handshake is complete and a certificate has been exchanged, then the * details of the remote certificate can be retrieved. * * This will usually be used by a client to check that the server's common * name matches the URL. * * @param ssl [in] An SSL object reference. * @param component [in] one of: * - SSL_X509_CERT_COMMON_NAME * - SSL_X509_CERT_ORGANIZATION * - SSL_X509_CERT_ORGANIZATIONAL_NAME * - SSL_X509_CA_CERT_COMMON_NAME * - SSL_X509_CA_CERT_ORGANIZATION * - SSL_X509_CA_CERT_ORGANIZATIONAL_NAME * @return The appropriate string (or null if not defined) * @note Verification build mode must be enabled. */ EXP_FUNC const char * STDCALL ssl_get_cert_dn(const SSL *ssl, int component); /** * @brief Retrieve a Subject Alternative DNSName * * When a handshake is complete and a certificate has been exchanged, then the * details of the remote certificate can be retrieved. * * This will usually be used by a client to check that the server's DNS * name matches the URL. * * @param ssl [in] An SSL object reference. * @param dnsindex [in] The index of the DNS name to retrieve. * @return The appropriate string (or null if not defined) * @note Verification build mode must be enabled. */ EXP_FUNC const char * STDCALL ssl_get_cert_subject_alt_dnsname(const SSL *ssl, int dnsindex); /** * @brief Force the client to perform its handshake again. * * For a client this involves sending another "client hello" message. * For the server is means sending a "hello request" message. * * This is a blocking call on the client (until the handshake completes). * * @param ssl [in] An SSL object reference. * @return SSL_OK if renegotiation instantiation was ok */ EXP_FUNC int STDCALL ssl_renegotiate(SSL *ssl); /** * @brief Process a file that is in binary DER or ASCII PEM format. * * These are temporary objects that are used to load private keys, * certificates etc into memory. * @param ssl_ctx [in] The client/server context. * @param obj_type [in] The format of the file. Can be one of: * - SSL_OBJ_X509_CERT (no password required) * - SSL_OBJ_X509_CACERT (no password required) * - SSL_OBJ_RSA_KEY (AES128/AES256 PEM encryption supported) * - SSL_OBJ_PKCS8 (RC4-128 encrypted data supported) * - SSL_OBJ_PKCS12 (RC4-128 encrypted data supported) * * PEM files are automatically detected (if supported). The object type is * also detected, and so is not relevant for these types of files. * @param filename [in] The location of a file in DER/PEM format. * @param password [in] The password used. Can be null if not required. * @return SSL_OK if all ok * @note Not available in skeleton build mode. */ EXP_FUNC int STDCALL ssl_obj_load(SSL_CTX *ssl_ctx, int obj_type, const char *filename, const char *password); /** * @brief Process binary data. * * These are temporary objects that are used to load private keys, * certificates etc into memory. * @param ssl_ctx [in] The client/server context. * @param obj_type [in] The format of the memory data. * @param data [in] The binary data to be loaded. * @param len [in] The amount of data to be loaded. * @param password [in] The password used. Can be null if not required. * @return SSL_OK if all ok * @see ssl_obj_load for more details on obj_type. */ EXP_FUNC int STDCALL ssl_obj_memory_load(SSL_CTX *ssl_ctx, int obj_type, const uint8_t *data, int len, const char *password); #ifdef CONFIG_SSL_GENERATE_X509_CERT /** * @brief Create an X.509 certificate. * * This certificate is a self-signed v1 cert with a fixed start/stop validity * times. It is signed with an internal private key in ssl_ctx. * * @param ssl_ctx [in] The client/server context. * @param options [in] Not used yet. * @param dn [in] An array of distinguished name strings. The array is defined * by: * - SSL_X509_CERT_COMMON_NAME (0) * - If SSL_X509_CERT_COMMON_NAME is empty or not defined, then the * hostname will be used. * - SSL_X509_CERT_ORGANIZATION (1) * - If SSL_X509_CERT_ORGANIZATION is empty or not defined, then $USERNAME * will be used. * - SSL_X509_CERT_ORGANIZATIONAL_NAME (2) * - SSL_X509_CERT_ORGANIZATIONAL_NAME is optional. * @param cert_data [out] The certificate as a sequence of bytes. * @return < 0 if an error, or the size of the certificate in bytes. * @note cert_data must be freed when there is no more need for it. */ EXP_FUNC int STDCALL ssl_x509_create(SSL_CTX *ssl_ctx, uint32_t options, const char * dn[], uint8_t **cert_data); #endif /** * @brief Return the axTLS library version as a string. */ EXP_FUNC const char * STDCALL ssl_version(void); /** @} */ #ifdef __cplusplus } #endif #endif