text: //
  // Context.h
  //
  // Library: NetSSL_OpenSSL
  // Package: SSLCore
  // Module:  Context
  //
  // Definition of the Context class.
  //
  // Copyright (c) 2006-2010, Applied Informatics Software Engineering GmbH.
  // and Contributors.
  //
  // SPDX-License-Identifier:	BSL-1.0
  //
  
  
  #ifndef NetSSL_Context_INCLUDED
  #define NetSSL_Context_INCLUDED
  
  
  #include "Poco/Net/NetSSL.h"
  #include "Poco/Net/SocketDefs.h"
  #include "Poco/Crypto/X509Certificate.h"
  #include "Poco/Crypto/EVPPKey.h"
  #include "Poco/Crypto/RSAKey.h"
  #include "Poco/RefCountedObject.h"
  #include "Poco/AutoPtr.h"
  #include <openssl/ssl.h>
  #include <cstdlib>
  
  
  namespace Poco {
  namespace Net {
  
  
  class NetSSL_API Context: public Poco::RefCountedObject
  	/// This class encapsulates context information for
  	/// an SSL server or client, such as the certificate
  	/// verification mode and the location of certificates
  	/// and private key files, as well as the list of
  	/// supported ciphers.
  	///
  	/// The Context class is also used to control
  	/// SSL session caching on the server and client side.
  	///
  	/// A Note Regarding TLSv1.3 Support:
  	///
  	/// TLSv1.3 support requires at least OpenSSL version 1.1.1.
  	/// Make sure that the TLSv1.3 cipher suites are enabled:
  	///
  	///   - TLS_AES_256_GCM_SHA384
  	///   - TLS_CHACHA20_POLY1305_SHA256
  	///   - TLS_AES_128_GCM_SHA256
  	///   - TLS_AES_128_CCM_8_SHA256
  	///   - TLS_AES_128_CCM_SHA256
  	///
  	/// The first three of the above cipher suites should be enabled
  	/// by default in OpenSSL if you do not provide an explicit
  	/// cipher configuration (cipherList).
  {
  public:
  	using Ptr = Poco::AutoPtr<Context>;
  
  	enum Usage
  	{
  		TLS_CLIENT_USE,     /// Context is used by a client for TLSv1 or higher. Use requireMinimumProtocol() or disableProtocols() to disable undesired older versions.
  		TLS_SERVER_USE,     /// Context is used by a client for TLSv1 or higher. Use requireMinimumProtocol() or disableProtocols() to disable undesired older versions.
  		CLIENT_USE, 	    /// DEPRECATED. Context is used by a client.
  		SERVER_USE,         /// DEPRECATED. Context is used by a server.
  		TLSV1_CLIENT_USE,   /// DEPRECATED. Context is used by a client requiring TLSv1.
  		TLSV1_SERVER_USE,   /// DEPRECATED. Context is used by a server requiring TLSv1.
  		TLSV1_1_CLIENT_USE, /// DEPRECATED. Context is used by a client requiring TLSv1.1 (OpenSSL 1.0.0 or newer).
  		TLSV1_1_SERVER_USE, /// DEPRECATED. Context is used by a server requiring TLSv1.1 (OpenSSL 1.0.0 or newer).
  		TLSV1_2_CLIENT_USE, /// DEPRECATED. Context is used by a client requiring TLSv1.2 (OpenSSL 1.0.1 or newer).
  		TLSV1_2_SERVER_USE, /// DEPRECATED. Context is used by a server requiring TLSv1.2 (OpenSSL 1.0.1 or newer).
  		TLSV1_3_CLIENT_USE, /// DEPRECATED. Context is used by a client requiring TLSv1.3 (OpenSSL 1.1.1 or newer).
  		TLSV1_3_SERVER_USE  /// DEPRECATED. Context is used by a server requiring TLSv1.3 (OpenSSL 1.1.1 or newer).
  	};
  
  	enum VerificationMode
  	{
  		VERIFY_NONE    = SSL_VERIFY_NONE,
  			/// Server: The server will not send a client certificate
  			/// request to the client, so the client will not send a certificate.
  			///
  			/// Client: If not using an anonymous cipher (by default disabled),
  			/// the server will send a certificate which will be checked, but
  			/// the result of the check will be ignored.
  
  		VERIFY_RELAXED = SSL_VERIFY_PEER,
  			/// Server: The server sends a client certificate request to the
  			/// client. The certificate returned (if any) is checked.
  			/// If the verification process fails, the TLS/SSL handshake is
  			/// immediately terminated with an alert message containing the
  			/// reason for the verification failure.
  			///
  			/// Client: The server certificate is verified, if one is provided.
  			/// If the verification process fails, the TLS/SSL handshake is
  			/// immediately terminated with an alert message containing the
  			/// reason for the verification failure.
  
  		VERIFY_STRICT  = SSL_VERIFY_PEER | SSL_VERIFY_FAIL_IF_NO_PEER_CERT,
  			/// Server: If the client did not return a certificate, the TLS/SSL
  			/// handshake is immediately terminated with a handshake failure
  			/// alert.
  			///
  			/// Client: Same as VERIFY_RELAXED.
  
  		VERIFY_ONCE    = SSL_VERIFY_PEER | SSL_VERIFY_CLIENT_ONCE
  			/// Server: Only request a client certificate on the initial
  			/// TLS/SSL handshake. Do not ask for a client certificate
  			/// again in case of a renegotiation.
  			///
  			/// Client: Same as VERIFY_RELAXED.
  	};
  
  	enum Protocols
  	{
  		PROTO_SSLV2   = 0x01,
  		PROTO_SSLV3   = 0x02,
  		PROTO_TLSV1   = 0x04,
  		PROTO_TLSV1_1 = 0x08,
  		PROTO_TLSV1_2 = 0x10,
  		PROTO_TLSV1_3 = 0x20
  	};
  
  	struct NetSSL_API Params
  	{
  		Params();
  			/// Initializes the struct with default values.
  
  		std::string privateKeyFile;
  			/// Path to the private key file used for encryption.
  			/// Can be empty if no private key file is used.
  
  		std::string certificateFile;
  			/// Path to the certificate file (in PEM format).
  			/// If the private key and the certificate are stored in the same file, this
  			/// can be empty if privateKeyFile is given.
  
  		std::string caLocation;
  			/// Path to the file or directory containing the CA/root certificates.
  			/// Can be empty if the OpenSSL builtin CA certificates
  			/// are used (see loadDefaultCAs).
  
  		VerificationMode verificationMode;
  			/// Specifies whether and how peer certificates are validated.
  			/// Defaults to VERIFY_RELAXED.
  
  		int verificationDepth;
  			/// Sets the upper limit for verification chain sizes. Verification
  			/// will fail if a certificate chain larger than this is encountered.
  			/// Defaults to 9.
  
  		bool loadDefaultCAs;
  			/// Specifies whether the builtin CA certificates from OpenSSL are used.
  			/// Defaults to false.
  
  		std::string cipherList;
  			/// Specifies the supported ciphers in OpenSSL notation.
  			/// Defaults to "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH".
  
  		std::string dhParamsFile;
  			/// Specifies a file containing Diffie-Hellman parameters.
  			/// If empty, the default parameters are used.
  
  		bool dhUse2048Bits;
  			/// If set to true, will use 2048-bit MODP Group with 256-bit
  			/// prime order subgroup (RFC5114) instead of 1024-bit for DH.
  
  		std::string ecdhCurve;
  			/// OpenSSL 1.0.1 and earlier:
  			///   Specifies the name of the curve to use for ECDH, based
  			///   on the curve names specified in RFC 4492.
  			///   Defaults to "prime256v1".
  			/// OpenSSL 1.0.2 to 1.1.0:
  			///   Specifies the colon-separated list of curves
  			///   to be used for ECDH, based on the curve names
  			///   defined by OpenSSL, such as
  			///   "X448:X25519:P-521:P-384:P-256"
  			///   Defaults to the subset supported by the OpenSSL version
  			///   among the above.
  			/// OpenSSL 1.1.1 and above:
  			///   Specifies the colon-separated list of groups
  			///   (some of which can be curves) to be used for ECDH
  			///   and other TLSv1.3 ephemeral key negotiation, based
  			///   on the group names defined by OpenSSL. Defaults to
  			///   "X448:X25519:ffdhe4096:ffdhe3072:ffdhe2048:ffdhe6144:ffdhe8192:P-521:P-384:P-256"
  	};
  
  	Context(Usage usage, const Params& params);
  		/// Creates a Context using the given parameters.
  		///
  		///   * usage specifies whether the context is used by a client or server.
  		///   * params specifies the context parameters.
  
  	Context(
  		Usage usage,
  		const std::string& privateKeyFile,
  		const std::string& certificateFile,
  		const std::string& caLocation,
  		VerificationMode verificationMode = VERIFY_RELAXED,
  		int verificationDepth = 9,
  		bool loadDefaultCAs = false,
  		const std::string& cipherList = "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
  		/// Creates a Context.
  		///
  		///   * usage specifies whether the context is used by a client or server.
  		///   * privateKeyFile contains the path to the private key file used for encryption.
  		///     Can be empty if no private key file is used.
  		///   * certificateFile contains the path to the certificate file (in PEM format).
  		///     If the private key and the certificate are stored in the same file, this
  		///     can be empty if privateKeyFile is given.
  		///   * caLocation contains the path to the file or directory containing the
  		///     CA/root certificates. Can be empty if the OpenSSL builtin CA certificates
  		///     are used (see loadDefaultCAs).
  		///   * verificationMode specifies whether and how peer certificates are validated.
  		///   * verificationDepth sets the upper limit for verification chain sizes. Verification
  		///     will fail if a certificate chain larger than this is encountered.
  		///   * loadDefaultCAs specifies whether the builtin CA certificates from OpenSSL are used.
  		///   * cipherList specifies the supported ciphers in OpenSSL notation.
  		///
  		/// Note: If the private key is protected by a passphrase, a PrivateKeyPassphraseHandler
  		/// must have been setup with the SSLManager, or the SSLManager's PrivateKeyPassphraseRequired
  		/// event must be handled.
  
  	Context(
  		Usage usage,
  		const std::string& caLocation,
  		VerificationMode verificationMode = VERIFY_RELAXED,
  		int verificationDepth = 9,
  		bool loadDefaultCAs = false,
  		const std::string& cipherList = "ALL:!ADH:!LOW:!EXP:!MD5:@STRENGTH");
  		/// Creates a Context.
  		///
  		///   * usage specifies whether the context is used by a client or server.
  		///   * caLocation contains the path to the file or directory containing the
  		///     CA/root certificates. Can be empty if the OpenSSL builtin CA certificates
  		///     are used (see loadDefaultCAs).
  		///   * verificationMode specifies whether and how peer certificates are validated.
  		///   * verificationDepth sets the upper limit for verification chain sizes. Verification
  		///     will fail if a certificate chain larger than this is encountered.
  		///   * loadDefaultCAs specifies whether the builtin CA certificates from OpenSSL are used.
  		///   * cipherList specifies the supported ciphers in OpenSSL notation.
  		///
  		/// Note that a private key and/or certificate must be specified with
  		/// usePrivateKey()/useCertificate() before the Context can be used.
  
  	~Context();
  		/// Destroys the Context.
  
  	void useCertificate(const Poco::Crypto::X509Certificate& certificate);
  		/// Sets the certificate to be used by the Context.
  		///
  		/// To set-up a complete certificate chain, it might be
  		/// necessary to call addChainCertificate() to specify
  		/// additional certificates.
  		///
  		/// Note that useCertificate() must always be called before
  		/// usePrivateKey().
  
  	void addChainCertificate(const Poco::Crypto::X509Certificate& certificate);
  		/// Adds a certificate for certificate chain validation.
  
  	void addCertificateAuthority(const Poco::Crypto::X509Certificate& certificate);
  		/// Add one trusted certification authority to be used by the Context.
  
  	void usePrivateKey(const Poco::Crypto::RSAKey& key);
  		/// Sets the private key to be used by the Context.
  		///
  		/// Note that useCertificate() must always be called before
  		/// usePrivateKey().
  		///
  		/// Note: If the private key is protected by a passphrase, a PrivateKeyPassphraseHandler
  		/// must have been setup with the SSLManager, or the SSLManager's PrivateKeyPassphraseRequired
  		/// event must be handled.
  
  	void usePrivateKey(const Poco::Crypto::EVPPKey &pkey);
  		/// Sets the private key to be used by the Context.
  		///
  		/// Note that useCertificate() must always be called before
  		/// usePrivateKey().
  		///
  		/// Note: If the private key is protected by a passphrase, a PrivateKeyPassphraseHandler
  		/// must have been setup with the SSLManager, or the SSLManager's PrivateKeyPassphraseRequired
  		/// event must be handled.
  
  	SSL_CTX* sslContext() const;
  		/// Returns the underlying OpenSSL SSL Context object.
  
  	Usage usage() const;
  		/// Returns whether the context is for use by a client or by a server
  		/// and whether TLSv1 is required.
  
  	bool isForServerUse() const;
  		/// Returns true iff the context is for use by a server.
  
  	Context::VerificationMode verificationMode() const;
  		/// Returns the verification mode.
  
  	void enableSessionCache(bool flag = true);
  		/// Enable or disable SSL/TLS session caching.
  		/// For session caching to work, it must be enabled
  		/// on the server, as well as on the client side.
  		///
  		/// The default is disabled session caching.
  		///
  		/// To enable session caching on the server side, use the
  		/// two-argument version of this method to specify
  		/// a session ID context.
  
  	void enableSessionCache(bool flag, const std::string& sessionIdContext);
  		/// Enables or disables SSL/TLS session caching on the server.
  		/// For session caching to work, it must be enabled
  		/// on the server, as well as on the client side.
  		///
  		/// SessionIdContext contains the application's unique
  		/// session ID context, which becomes part of each
  		/// session identifier generated by the server within this
  		/// context. SessionIdContext can be an arbitrary sequence
  		/// of bytes with a maximum length of SSL_MAX_SSL_SESSION_ID_LENGTH.
  		///
  		/// A non-empty sessionIdContext should be specified even if
  		/// session caching is disabled to avoid problems with clients
  		/// requesting to reuse a session (e.g. Firefox 3.6).
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	bool sessionCacheEnabled() const;
  		/// Returns true iff the session cache is enabled.
  
  	void setSessionCacheSize(std::size_t size);
  		/// Sets the maximum size of the server session cache, in number of
  		/// sessions. The default size (according to OpenSSL documentation)
  		/// is 1024*20, which may be too large for many applications,
  		/// especially on embedded platforms with limited memory.
  		///
  		/// Specifying a size of 0 will set an unlimited cache size.
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	std::size_t getSessionCacheSize() const;
  		/// Returns the current maximum size of the server session cache.
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	void setSessionTimeout(long seconds);
  		/// Sets the timeout (in seconds) of cached sessions on the server.
  		/// A cached session will be removed from the cache if it has
  		/// not been used for the given number of seconds.
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	long getSessionTimeout() const;
  		/// Returns the timeout (in seconds) of cached sessions on the server.
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	void flushSessionCache();
  		/// Flushes the SSL session cache on the server.
  		///
  		/// This method may only be called on SERVER_USE Context objects.
  
  	void enableExtendedCertificateVerification(bool flag = true);
  		/// Enable or disable the automatic post-connection
  		/// extended certificate verification.
  		///
  		/// See X509Certificate::verify() for more information.
  
  	bool extendedCertificateVerificationEnabled() const;
  		/// Returns true iff automatic extended certificate
  		/// verification is enabled.
  
  	void disableStatelessSessionResumption();
  		/// Newer versions of OpenSSL support RFC 4507 tickets for stateless
  		/// session resumption.
  		///
  		/// The feature can be disabled by calling this method.
  
  	void disableProtocols(int protocols);
  		/// Disables the given protocols.
  		///
  		/// The protocols to be disabled are specified by OR-ing
  		/// values from the Protocols enumeration, e.g.:
  		///
  		///   context.disableProtocols(PROTO_SSLV2 | PROTO_SSLV3);
  
  	void requireMinimumProtocol(Protocols protocol);
  		/// Disables all protocol version lower than the given one.
  		/// To require at least TLS 1.2 or later:
  		///
  		///   context.requireMinimumProtocol(PROTO_TLSV1_2);
  
  	void preferServerCiphers();
  		/// When choosing a cipher, use the server's preferences instead of the client
  		/// preferences. When not called, the SSL server will always follow the clients
  		/// preferences. When called, the SSL/TLS server will choose following its own
  		/// preferences.
  
  private:
  	void init(const Params& params);
  		/// Initializes the Context with the given parameters.
  
  	void initDH(bool use2048Bits, const std::string& dhFile);
  		/// Initializes the Context with Diffie-Hellman parameters.
  
  	void initECDH(const std::string& curve);
  		/// Initializes the Context with Elliptic-Curve Diffie-Hellman key
  		/// exchange curve parameters.
  
  	void createSSLContext();
  		/// Create a SSL_CTX object according to Context configuration.
  
  	Usage _usage;
  	VerificationMode _mode;
  	SSL_CTX* _pSSLContext;
  	bool _extendedCertificateVerification;
  };
  
  
  //
  // inlines
  //
  inline Context::Usage Context::usage() const
  {
  	return _usage;
  }
  
  
  inline bool Context::isForServerUse() const
  {
  	return _usage == SERVER_USE
  		|| _usage == TLS_SERVER_USE
  		|| _usage == TLSV1_SERVER_USE
  		|| _usage == TLSV1_1_SERVER_USE
  		|| _usage == TLSV1_2_SERVER_USE
  		|| _usage == TLSV1_3_SERVER_USE;
  }
  
  
  inline Context::VerificationMode Context::verificationMode() const
  {
  	return _mode;
  }
  
  
  inline SSL_CTX* Context::sslContext() const
  {
  	return _pSSLContext;
  }
  
  
  inline bool Context::extendedCertificateVerificationEnabled() const
  {
  	return _extendedCertificateVerification;
  }
  
  
  } } // namespace Poco::Net
  
  
  #endif // NetSSL_Context_INCLUDED
  