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diff --git a/doc/api/ssl.rst b/doc/api/ssl.rst new file mode 100644 index 0000000..1eed876 --- /dev/null +++ b/doc/api/ssl.rst @@ -0,0 +1,677 @@ +.. _openssl-ssl: + +:py:mod:`SSL` --- An interface to the SSL-specific parts of OpenSSL +=================================================================== + +.. py:module:: OpenSSL.SSL + :synopsis: An interface to the SSL-specific parts of OpenSSL + + +This module handles things specific to SSL. There are two objects defined: +Context, Connection. + +.. py:data:: SSLv2_METHOD + SSLv3_METHOD + SSLv23_METHOD + TLSv1_METHOD + + These constants represent the different SSL methods to use when creating a + context object. + + +.. py:data:: VERIFY_NONE + VERIFY_PEER + VERIFY_FAIL_IF_NO_PEER_CERT + + These constants represent the verification mode used by the Context + object's :py:meth:`set_verify` method. + + +.. py:data:: FILETYPE_PEM + FILETYPE_ASN1 + + File type constants used with the :py:meth:`use_certificate_file` and + :py:meth:`use_privatekey_file` methods of Context objects. + + +.. py:data:: OP_SINGLE_DH_USE + OP_EPHEMERAL_RSA + OP_NO_SSLv2 + OP_NO_SSLv3 + OP_NO_TLSv1 + OP_NO_TICKET + OP_NO_COMPRESSION + + Constants used with :py:meth:`set_options` of Context objects. + + :py:const:`OP_SINGLE_DH_USE` means to always create a new key when using + ephemeral Diffie-Hellman. :py:const:`OP_EPHEMERAL_RSA` means to always use + ephemeral RSA keys when doing RSA operations. :py:const:`OP_NO_SSLv2`, + :py:const:`OP_NO_SSLv3` and :py:const:`OP_NO_TLSv1` means to disable those + specific protocols. This is interesting if you're using e.g. + :py:const:`SSLv23_METHOD` to get an SSLv2-compatible handshake, but don't want + to use SSLv2. + + +.. py:data:: MODE_NO_COMPRESSION + + Constant used with :py:meth:`set_mode` of Context objects to disable + automatic compression of application traffic. + + +.. py:data:: SSLEAY_VERSION + SSLEAY_CFLAGS + SSLEAY_BUILT_ON + SSLEAY_PLATFORM + SSLEAY_DIR + + Constants used with :py:meth:`SSLeay_version` to specify what OpenSSL version + information to retrieve. See the man page for the :py:func:`SSLeay_version` C + API for details. + + +.. py:data:: OPENSSL_VERSION_NUMBER + + An integer giving the version number of the OpenSSL library used to build this + version of pyOpenSSL. See the man page for the :py:func:`SSLeay_version` C API + for details. + + +.. py:function:: SSLeay_version(type) + + Retrieve a string describing some aspect of the underlying OpenSSL version. The + type passed in should be one of the :py:const:`SSLEAY_*` constants defined in + this module. + + +.. py:data:: ContextType + + See :py:class:`Context`. + + +.. py:class:: Context(method) + + A class representing SSL contexts. Contexts define the parameters of one or + more SSL connections. + + *method* should be :py:const:`SSLv2_METHOD`, :py:const:`SSLv3_METHOD`, + :py:const:`SSLv23_METHOD` or :py:const:`TLSv1_METHOD`. + + +.. py:data:: ConnectionType + + See :py:class:`Connection`. + + +.. py:class:: Connection(context, socket) + + A class representing SSL connections. + + *context* should be an instance of :py:class:`Context` and *socket* + should be a socket [#connection-context-socket]_ object. *socket* may be + *None*; in this case, the Connection is created with a memory BIO: see + the :py:meth:`bio_read`, :py:meth:`bio_write`, and :py:meth:`bio_shutdown` + methods. + +.. py:exception:: Error + + This exception is used as a base class for the other SSL-related + exceptions, but may also be raised directly. + + Whenever this exception is raised directly, it has a list of error messages + from the OpenSSL error queue, where each item is a tuple *(lib, function, + reason)*. Here *lib*, *function* and *reason* are all strings, describing + where and what the problem is. See :manpage:`err(3)` for more information. + + +.. py:exception:: ZeroReturnError + + This exception matches the error return code + :py:data:`SSL_ERROR_ZERO_RETURN`, and is raised when the SSL Connection has + been closed. In SSL 3.0 and TLS 1.0, this only occurs if a closure alert has + occurred in the protocol, i.e. the connection has been closed cleanly. Note + that this does not necessarily mean that the transport layer (e.g. a socket) + has been closed. + + It may seem a little strange that this is an exception, but it does match an + :py:data:`SSL_ERROR` code, and is very convenient. + + +.. py:exception:: WantReadError + + The operation did not complete; the same I/O method should be called again + later, with the same arguments. Any I/O method can lead to this since new + handshakes can occur at any time. + + The wanted read is for **dirty** data sent over the network, not the + **clean** data inside the tunnel. For a socket based SSL connection, + **read** means data coming at us over the network. Until that read + succeeds, the attempted :py:meth:`OpenSSL.SSL.Connection.recv`, + :py:meth:`OpenSSL.SSL.Connection.send`, or + :py:meth:`OpenSSL.SSL.Connection.do_handshake` is prevented or incomplete. You + probably want to :py:meth:`select()` on the socket before trying again. + + +.. py:exception:: WantWriteError + + See :py:exc:`WantReadError`. The socket send buffer may be too full to + write more data. + + +.. py:exception:: WantX509LookupError + + The operation did not complete because an application callback has asked to be + called again. The I/O method should be called again later, with the same + arguments. + + .. note:: This won't occur in this version, as there are no such + callbacks in this version. + + +.. py:exception:: SysCallError + + The :py:exc:`SysCallError` occurs when there's an I/O error and OpenSSL's + error queue does not contain any information. This can mean two things: An + error in the transport protocol, or an end of file that violates the protocol. + The parameter to the exception is always a pair *(errnum, + errstr)*. + + + +.. _openssl-context: + +Context objects +--------------- + +Context objects have the following methods: + +.. :py:class:: OpenSSL.SSL.Context + +.. py:method:: Context.check_privatekey() + + Check if the private key (loaded with :py:meth:`use_privatekey`) matches the + certificate (loaded with :py:meth:`use_certificate`). Returns + :py:data:`None` if they match, raises :py:exc:`Error` otherwise. + + +.. py:method:: Context.get_app_data() + + Retrieve application data as set by :py:meth:`set_app_data`. + + +.. py:method:: Context.get_cert_store() + + Retrieve the certificate store (a X509Store object) that the context uses. + This can be used to add "trusted" certificates without using the. + :py:meth:`load_verify_locations` method. + + +.. py:method:: Context.get_timeout() + + Retrieve session timeout, as set by :py:meth:`set_timeout`. The default is 300 + seconds. + + +.. py:method:: Context.get_verify_depth() + + Retrieve the Context object's verify depth, as set by + :py:meth:`set_verify_depth`. + + +.. py:method:: Context.get_verify_mode() + + Retrieve the Context object's verify mode, as set by :py:meth:`set_verify`. + + +.. py:method:: Context.load_client_ca(pemfile) + + Read a file with PEM-formatted certificates that will be sent to the client + when requesting a client certificate. + + +.. py:method:: Context.set_client_ca_list(certificate_authorities) + + Replace the current list of preferred certificate signers that would be + sent to the client when requesting a client certificate with the + *certificate_authorities* sequence of :py:class:`OpenSSL.crypto.X509Name`'s. + + .. versionadded:: 0.10 + + +.. py:method:: Context.add_client_ca(certificate_authority) + + Extract a :py:class:`OpenSSL.crypto.X509Name` from the *certificate_authority* + :py:class:`OpenSSL.crypto.X509` certificate and add it to the list of preferred + certificate signers sent to the client when requesting a client certificate. + + .. versionadded:: 0.10 + + +.. py:method:: Context.load_verify_locations(pemfile, capath) + + Specify where CA certificates for verification purposes are located. These + are trusted certificates. Note that the certificates have to be in PEM + format. If capath is passed, it must be a directory prepared using the + ``c_rehash`` tool included with OpenSSL. Either, but not both, of + *pemfile* or *capath* may be :py:data:`None`. + + +.. py:method:: Context.set_default_verify_paths() + + Specify that the platform provided CA certificates are to be used for + verification purposes. This method may not work properly on OS X. + + +.. py:method:: Context.load_tmp_dh(dhfile) + + Load parameters for Ephemeral Diffie-Hellman from *dhfile*. + + +.. py:method:: Context.set_app_data(data) + + Associate *data* with this Context object. *data* can be retrieved + later using the :py:meth:`get_app_data` method. + + +.. py:method:: Context.set_cipher_list(ciphers) + + Set the list of ciphers to be used in this context. See the OpenSSL manual for + more information (e.g. :manpage:`ciphers(1)`) + + +.. py:method:: Context.set_info_callback(callback) + + Set the information callback to *callback*. This function will be called + from time to time during SSL handshakes. + + *callback* should take three arguments: a Connection object and two integers. + The first integer specifies where in the SSL handshake the function was + called, and the other the return code from a (possibly failed) internal + function call. + + +.. py:method:: Context.set_options(options) + + Add SSL options. Options you have set before are not cleared! + This method should be used with the :py:const:`OP_*` constants. + + +.. py:method:: Context.set_mode(mode) + + Add SSL mode. Modes you have set before are not cleared! This method should + be used with the :py:const:`MODE_*` constants. + + +.. py:method:: Context.set_passwd_cb(callback[, userdata]) + + Set the passphrase callback to *callback*. This function will be called + when a private key with a passphrase is loaded. *callback* must accept + three positional arguments. First, an integer giving the maximum length of + the passphrase it may return. If the returned passphrase is longer than + this, it will be truncated. Second, a boolean value which will be true if + the user should be prompted for the passphrase twice and the callback should + verify that the two values supplied are equal. Third, the value given as the + *userdata* parameter to :py:meth:`set_passwd_cb`. If an error occurs, + *callback* should return a false value (e.g. an empty string). + + +.. py:method:: Context.set_session_id(name) + + Set the context *name* within which a session can be reused for this + Context object. This is needed when doing session resumption, because there is + no way for a stored session to know which Context object it is associated with. + *name* may be any binary data. + + +.. py:method:: Context.set_timeout(timeout) + + Set the timeout for newly created sessions for this Context object to + *timeout*. *timeout* must be given in (whole) seconds. The default + value is 300 seconds. See the OpenSSL manual for more information (e.g. + :manpage:`SSL_CTX_set_timeout(3)`). + + +.. py:method:: Context.set_verify(mode, callback) + + Set the verification flags for this Context object to *mode* and specify + that *callback* should be used for verification callbacks. *mode* should be + one of :py:const:`VERIFY_NONE` and :py:const:`VERIFY_PEER`. If + :py:const:`VERIFY_PEER` is used, *mode* can be OR:ed with + :py:const:`VERIFY_FAIL_IF_NO_PEER_CERT` and :py:const:`VERIFY_CLIENT_ONCE` + to further control the behaviour. + + *callback* should take five arguments: A Connection object, an X509 object, + and three integer variables, which are in turn potential error number, error + depth and return code. *callback* should return true if verification passes + and false otherwise. + + +.. py:method:: Context.set_verify_depth(depth) + + Set the maximum depth for the certificate chain verification that shall be + allowed for this Context object. + + +.. py:method:: Context.use_certificate(cert) + + Use the certificate *cert* which has to be a X509 object. + + +.. py:method:: Context.add_extra_chain_cert(cert) + + Adds the certificate *cert*, which has to be a X509 object, to the + certificate chain presented together with the certificate. + + +.. py:method:: Context.use_certificate_chain_file(file) + + Load a certificate chain from *file* which must be PEM encoded. + + +.. py:method:: Context.use_privatekey(pkey) + + Use the private key *pkey* which has to be a PKey object. + + +.. py:method:: Context.use_certificate_file(file[, format]) + + Load the first certificate found in *file*. The certificate must be in the + format specified by *format*, which is either :py:const:`FILETYPE_PEM` or + :py:const:`FILETYPE_ASN1`. The default is :py:const:`FILETYPE_PEM`. + + +.. py:method:: Context.use_privatekey_file(file[, format]) + + Load the first private key found in *file*. The private key must be in the + format specified by *format*, which is either :py:const:`FILETYPE_PEM` or + :py:const:`FILETYPE_ASN1`. The default is :py:const:`FILETYPE_PEM`. + + +.. py:method:: Context.set_tlsext_servername_callback(callback) + + Specify a one-argument callable to use as the TLS extension server name + callback. When a connection using the server name extension is made using + this context, the callback will be invoked with the :py:class:`Connection` + instance. + + .. versionadded:: 0.13 + + +.. _openssl-connection: + +Connection objects +------------------ + +Connection objects have the following methods: + +.. py:method:: Connection.accept() + + Call the :py:meth:`accept` method of the underlying socket and set up SSL on the + returned socket, using the Context object supplied to this Connection object at + creation. Returns a pair *(conn, address)*. where *conn* is the new + Connection object created, and *address* is as returned by the socket's + :py:meth:`accept`. + + +.. py:method:: Connection.bind(address) + + Call the :py:meth:`bind` method of the underlying socket. + + +.. py:method:: Connection.close() + + Call the :py:meth:`close` method of the underlying socket. Note: If you want + correct SSL closure, you need to call the :py:meth:`shutdown` method first. + + +.. py:method:: Connection.connect(address) + + Call the :py:meth:`connect` method of the underlying socket and set up SSL on the + socket, using the Context object supplied to this Connection object at + creation. + + +.. py:method:: Connection.connect_ex(address) + + Call the :py:meth:`connect_ex` method of the underlying socket and set up SSL on + the socket, using the Context object supplied to this Connection object at + creation. Note that if the :py:meth:`connect_ex` method of the socket doesn't + return 0, SSL won't be initialized. + + +.. py:method:: Connection.do_handshake() + + Perform an SSL handshake (usually called after :py:meth:`renegotiate` or one of + :py:meth:`set_accept_state` or :py:meth:`set_accept_state`). This can raise the + same exceptions as :py:meth:`send` and :py:meth:`recv`. + + +.. py:method:: Connection.fileno() + + Retrieve the file descriptor number for the underlying socket. + + +.. py:method:: Connection.listen(backlog) + + Call the :py:meth:`listen` method of the underlying socket. + + +.. py:method:: Connection.get_app_data() + + Retrieve application data as set by :py:meth:`set_app_data`. + + +.. py:method:: Connection.get_cipher_list() + + Retrieve the list of ciphers used by the Connection object. WARNING: This API + has changed. It used to take an optional parameter and just return a string, + but not it returns the entire list in one go. + + +.. py:method:: Connection.get_client_ca_list() + + Retrieve the list of preferred client certificate issuers sent by the server + as :py:class:`OpenSSL.crypto.X509Name` objects. + + If this is a client :py:class:`Connection`, the list will be empty until the + connection with the server is established. + + If this is a server :py:class:`Connection`, return the list of certificate + authorities that will be sent or has been sent to the client, as controlled + by this :py:class:`Connection`'s :py:class:`Context`. + + .. versionadded:: 0.10 + + +.. py:method:: Connection.get_context() + + Retrieve the Context object associated with this Connection. + + +.. py:method:: Connection.set_context(context) + + Specify a replacement Context object for this Connection. + + +.. py:method:: Connection.get_peer_certificate() + + Retrieve the other side's certificate (if any) + + +.. py:method:: Connection.get_peer_cert_chain() + + Retrieve the tuple of the other side's certificate chain (if any) + + +.. py:method:: Connection.getpeername() + + Call the :py:meth:`getpeername` method of the underlying socket. + + +.. py:method:: Connection.getsockname() + + Call the :py:meth:`getsockname` method of the underlying socket. + + +.. py:method:: Connection.getsockopt(level, optname[, buflen]) + + Call the :py:meth:`getsockopt` method of the underlying socket. + + +.. py:method:: Connection.pending() + + Retrieve the number of bytes that can be safely read from the SSL buffer + (**not** the underlying transport buffer). + + +.. py:method:: Connection.recv(bufsize) + + Receive data from the Connection. The return value is a string representing the + data received. The maximum amount of data to be received at once, is specified + by *bufsize*. + + +.. py:method:: Connection.bio_write(bytes) + + If the Connection was created with a memory BIO, this method can be used to add + bytes to the read end of that memory BIO. The Connection can then read the + bytes (for example, in response to a call to :py:meth:`recv`). + + +.. py:method:: Connection.renegotiate() + + Renegotiate the SSL session. Call this if you wish to change cipher suites or + anything like that. + + +.. py:method:: Connection.send(string) + + Send the *string* data to the Connection. + + +.. py:method:: Connection.bio_read(bufsize) + + If the Connection was created with a memory BIO, this method can be used to + read bytes from the write end of that memory BIO. Many Connection methods will + add bytes which must be read in this manner or the buffer will eventually fill + up and the Connection will be able to take no further actions. + + +.. py:method:: Connection.sendall(string) + + Send all of the *string* data to the Connection. This calls :py:meth:`send` + repeatedly until all data is sent. If an error occurs, it's impossible to tell + how much data has been sent. + + +.. py:method:: Connection.set_accept_state() + + Set the connection to work in server mode. The handshake will be handled + automatically by read/write. + + +.. py:method:: Connection.set_app_data(data) + + Associate *data* with this Connection object. *data* can be retrieved + later using the :py:meth:`get_app_data` method. + + +.. py:method:: Connection.set_connect_state() + + Set the connection to work in client mode. The handshake will be handled + automatically by read/write. + + +.. py:method:: Connection.setblocking(flag) + + Call the :py:meth:`setblocking` method of the underlying socket. + + +.. py:method:: Connection.setsockopt(level, optname, value) + + Call the :py:meth:`setsockopt` method of the underlying socket. + + +.. py:method:: Connection.shutdown() + + Send the shutdown message to the Connection. Returns true if the shutdown + message exchange is completed and false otherwise (in which case you call + :py:meth:`recv` or :py:meth:`send` when the connection becomes + readable/writeable. + + +.. py:method:: Connection.get_shutdown() + + Get the shutdown state of the Connection. Returns a bitvector of either or + both of *SENT_SHUTDOWN* and *RECEIVED_SHUTDOWN*. + + +.. py:method:: Connection.set_shutdown(state) + + Set the shutdown state of the Connection. *state* is a bitvector of + either or both of *SENT_SHUTDOWN* and *RECEIVED_SHUTDOWN*. + + +.. py:method:: Connection.sock_shutdown(how) + + Call the :py:meth:`shutdown` method of the underlying socket. + + +.. py:method:: Connection.bio_shutdown() + + If the Connection was created with a memory BIO, this method can be used to + indicate that *end of file* has been reached on the read end of that memory + BIO. + + +.. py:method:: Connection.state_string() + + Retrieve a verbose string detailing the state of the Connection. + + +.. py:method:: Connection.client_random() + + Retrieve the random value used with the client hello message. + + +.. py:method:: Connection.server_random() + + Retrieve the random value used with the server hello message. + + +.. py:method:: Connection.master_key() + + Retrieve the value of the master key for this session. + + +.. py:method:: Connection.want_read() + + Checks if more data has to be read from the transport layer to complete an + operation. + + +.. py:method:: Connection.want_write() + + Checks if there is data to write to the transport layer to complete an + operation. + + +.. py:method:: Connection.set_tlsext_host_name(name) + + Specify the byte string to send as the server name in the client hello message. + + .. versionadded:: 0.13 + + +.. py:method:: Connection.get_servername() + + Get the value of the server name received in the client hello message. + + .. versionadded:: 0.13 + + +.. Rubric:: Footnotes + +.. [#connection-context-socket] Actually, all that is required is an object that + **behaves** like a socket, you could even use files, even though it'd be + tricky to get the handshakes right! |