Antoine Pitrou | e1bc898 | 2011-01-02 22:12:22 +0000 | [diff] [blame] | 1 | :mod:`ssl` --- TLS/SSL wrapper for socket objects |
| 2 | ================================================= |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 3 | |
| 4 | .. module:: ssl |
Antoine Pitrou | e1bc898 | 2011-01-02 22:12:22 +0000 | [diff] [blame] | 5 | :synopsis: TLS/SSL wrapper for socket objects |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 6 | |
| 7 | .. moduleauthor:: Bill Janssen <bill.janssen@gmail.com> |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 8 | .. sectionauthor:: Bill Janssen <bill.janssen@gmail.com> |
| 9 | |
Terry Jan Reedy | fa089b9 | 2016-06-11 15:02:54 -0400 | [diff] [blame] | 10 | **Source code:** :source:`Lib/ssl.py` |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 11 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 12 | .. index:: single: OpenSSL; (use in module ssl) |
| 13 | |
| 14 | .. index:: TLS, SSL, Transport Layer Security, Secure Sockets Layer |
| 15 | |
Raymond Hettinger | 469271d | 2011-01-27 20:38:46 +0000 | [diff] [blame] | 16 | -------------- |
| 17 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 18 | This module provides access to Transport Layer Security (often known as "Secure |
| 19 | Sockets Layer") encryption and peer authentication facilities for network |
| 20 | sockets, both client-side and server-side. This module uses the OpenSSL |
| 21 | library. It is available on all modern Unix systems, Windows, Mac OS X, and |
| 22 | probably additional platforms, as long as OpenSSL is installed on that platform. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 23 | |
| 24 | .. note:: |
| 25 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 26 | Some behavior may be platform dependent, since calls are made to the |
| 27 | operating system socket APIs. The installed version of OpenSSL may also |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 28 | cause variations in behavior. For example, TLSv1.1 and TLSv1.2 come with |
| 29 | openssl version 1.0.1. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 30 | |
Christian Heimes | 3046fe4 | 2013-10-29 21:08:56 +0100 | [diff] [blame] | 31 | .. warning:: |
Antoine Pitrou | 9eefe91 | 2013-11-17 15:35:33 +0100 | [diff] [blame] | 32 | Don't use this module without reading the :ref:`ssl-security`. Doing so |
| 33 | may lead to a false sense of security, as the default settings of the |
| 34 | ssl module are not necessarily appropriate for your application. |
Christian Heimes | 3046fe4 | 2013-10-29 21:08:56 +0100 | [diff] [blame] | 35 | |
Christian Heimes | 3046fe4 | 2013-10-29 21:08:56 +0100 | [diff] [blame] | 36 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 37 | This section documents the objects and functions in the ``ssl`` module; for more |
| 38 | general information about TLS, SSL, and certificates, the reader is referred to |
| 39 | the documents in the "See Also" section at the bottom. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 40 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 41 | This module provides a class, :class:`ssl.SSLSocket`, which is derived from the |
| 42 | :class:`socket.socket` type, and provides a socket-like wrapper that also |
| 43 | encrypts and decrypts the data going over the socket with SSL. It supports |
Antoine Pitrou | dab6426 | 2010-09-19 13:31:06 +0000 | [diff] [blame] | 44 | additional methods such as :meth:`getpeercert`, which retrieves the |
| 45 | certificate of the other side of the connection, and :meth:`cipher`,which |
| 46 | retrieves the cipher being used for the secure connection. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 47 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 48 | For more sophisticated applications, the :class:`ssl.SSLContext` class |
| 49 | helps manage settings and certificates, which can then be inherited |
| 50 | by SSL sockets created through the :meth:`SSLContext.wrap_socket` method. |
| 51 | |
Mayank Singhal | 9ef1b06 | 2018-06-05 19:44:37 +0530 | [diff] [blame] | 52 | .. versionchanged:: 3.5.3 |
| 53 | Updated to support linking with OpenSSL 1.1.0 |
| 54 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 55 | .. versionchanged:: 3.6 |
| 56 | |
| 57 | OpenSSL 0.9.8, 1.0.0 and 1.0.1 are deprecated and no longer supported. |
| 58 | In the future the ssl module will require at least OpenSSL 1.0.2 or |
| 59 | 1.1.0. |
| 60 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 61 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 62 | Functions, Constants, and Exceptions |
| 63 | ------------------------------------ |
| 64 | |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 65 | |
| 66 | Socket creation |
| 67 | ^^^^^^^^^^^^^^^ |
| 68 | |
| 69 | Since Python 3.2 and 2.7.9, it is recommended to use the |
| 70 | :meth:`SSLContext.wrap_socket` of an :class:`SSLContext` instance to wrap |
| 71 | sockets as :class:`SSLSocket` objects. The helper functions |
| 72 | :func:`create_default_context` returns a new context with secure default |
| 73 | settings. The old :func:`wrap_socket` function is deprecated since it is |
| 74 | both inefficient and has no support for server name indication (SNI) and |
| 75 | hostname matching. |
| 76 | |
| 77 | Client socket example with default context and IPv4/IPv6 dual stack:: |
| 78 | |
| 79 | import socket |
| 80 | import ssl |
| 81 | |
| 82 | hostname = 'www.python.org' |
| 83 | context = ssl.create_default_context() |
| 84 | |
| 85 | with socket.create_connection((hostname, 443)) as sock: |
| 86 | with context.wrap_socket(sock, server_hostname=hostname) as ssock: |
| 87 | print(ssock.version()) |
| 88 | |
| 89 | |
| 90 | Client socket example with custom context and IPv4:: |
| 91 | |
| 92 | hostname = 'www.python.org' |
| 93 | # PROTOCOL_TLS_CLIENT requires valid cert chain and hostname |
| 94 | context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) |
| 95 | context.load_verify_locations('path/to/cabundle.pem') |
| 96 | |
| 97 | with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock: |
| 98 | with context.wrap_socket(sock, server_hostname=hostname) as ssock: |
| 99 | print(ssock.version()) |
| 100 | |
| 101 | |
| 102 | Server socket example listening on localhost IPv4:: |
| 103 | |
| 104 | context = ssl.SSLContext(ssl.PROTOCOL_TLS_SERVER) |
| 105 | context.load_cert_chain('/path/to/certchain.pem', '/path/to/private.key') |
| 106 | |
| 107 | with socket.socket(socket.AF_INET, socket.SOCK_STREAM, 0) as sock: |
| 108 | sock.bind(('127.0.0.1', 8443)) |
| 109 | sock.listen(5) |
| 110 | with context.wrap_socket(sock, server_side=True) as ssock: |
| 111 | conn, addr = ssock.accept() |
| 112 | ... |
| 113 | |
| 114 | |
| 115 | Context creation |
| 116 | ^^^^^^^^^^^^^^^^ |
| 117 | |
| 118 | A convenience function helps create :class:`SSLContext` objects for common |
| 119 | purposes. |
| 120 | |
| 121 | .. function:: create_default_context(purpose=Purpose.SERVER_AUTH, cafile=None, capath=None, cadata=None) |
| 122 | |
| 123 | Return a new :class:`SSLContext` object with default settings for |
| 124 | the given *purpose*. The settings are chosen by the :mod:`ssl` module, |
| 125 | and usually represent a higher security level than when calling the |
| 126 | :class:`SSLContext` constructor directly. |
| 127 | |
| 128 | *cafile*, *capath*, *cadata* represent optional CA certificates to |
| 129 | trust for certificate verification, as in |
| 130 | :meth:`SSLContext.load_verify_locations`. If all three are |
| 131 | :const:`None`, this function can choose to trust the system's default |
| 132 | CA certificates instead. |
| 133 | |
| 134 | The settings are: :data:`PROTOCOL_TLS`, :data:`OP_NO_SSLv2`, and |
| 135 | :data:`OP_NO_SSLv3` with high encryption cipher suites without RC4 and |
| 136 | without unauthenticated cipher suites. Passing :data:`~Purpose.SERVER_AUTH` |
| 137 | as *purpose* sets :data:`~SSLContext.verify_mode` to :data:`CERT_REQUIRED` |
| 138 | and either loads CA certificates (when at least one of *cafile*, *capath* or |
| 139 | *cadata* is given) or uses :meth:`SSLContext.load_default_certs` to load |
| 140 | default CA certificates. |
| 141 | |
| 142 | .. note:: |
| 143 | The protocol, options, cipher and other settings may change to more |
| 144 | restrictive values anytime without prior deprecation. The values |
| 145 | represent a fair balance between compatibility and security. |
| 146 | |
| 147 | If your application needs specific settings, you should create a |
| 148 | :class:`SSLContext` and apply the settings yourself. |
| 149 | |
| 150 | .. note:: |
| 151 | If you find that when certain older clients or servers attempt to connect |
| 152 | with a :class:`SSLContext` created by this function that they get an error |
| 153 | stating "Protocol or cipher suite mismatch", it may be that they only |
| 154 | support SSL3.0 which this function excludes using the |
| 155 | :data:`OP_NO_SSLv3`. SSL3.0 is widely considered to be `completely broken |
| 156 | <https://en.wikipedia.org/wiki/POODLE>`_. If you still wish to continue to |
| 157 | use this function but still allow SSL 3.0 connections you can re-enable |
| 158 | them using:: |
| 159 | |
| 160 | ctx = ssl.create_default_context(Purpose.CLIENT_AUTH) |
| 161 | ctx.options &= ~ssl.OP_NO_SSLv3 |
| 162 | |
| 163 | .. versionadded:: 3.4 |
| 164 | |
| 165 | .. versionchanged:: 3.4.4 |
| 166 | |
| 167 | RC4 was dropped from the default cipher string. |
| 168 | |
| 169 | .. versionchanged:: 3.6 |
| 170 | |
| 171 | ChaCha20/Poly1305 was added to the default cipher string. |
| 172 | |
| 173 | 3DES was dropped from the default cipher string. |
| 174 | |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 175 | |
| 176 | Exceptions |
| 177 | ^^^^^^^^^^ |
| 178 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 179 | .. exception:: SSLError |
| 180 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 181 | Raised to signal an error from the underlying SSL implementation |
| 182 | (currently provided by the OpenSSL library). This signifies some |
| 183 | problem in the higher-level encryption and authentication layer that's |
| 184 | superimposed on the underlying network connection. This error |
Antoine Pitrou | 5574c30 | 2011-10-12 17:53:43 +0200 | [diff] [blame] | 185 | is a subtype of :exc:`OSError`. The error code and message of |
| 186 | :exc:`SSLError` instances are provided by the OpenSSL library. |
| 187 | |
| 188 | .. versionchanged:: 3.3 |
| 189 | :exc:`SSLError` used to be a subtype of :exc:`socket.error`. |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 190 | |
Antoine Pitrou | 3b36fb1 | 2012-06-22 21:11:52 +0200 | [diff] [blame] | 191 | .. attribute:: library |
| 192 | |
| 193 | A string mnemonic designating the OpenSSL submodule in which the error |
| 194 | occurred, such as ``SSL``, ``PEM`` or ``X509``. The range of possible |
| 195 | values depends on the OpenSSL version. |
| 196 | |
| 197 | .. versionadded:: 3.3 |
| 198 | |
| 199 | .. attribute:: reason |
| 200 | |
| 201 | A string mnemonic designating the reason this error occurred, for |
| 202 | example ``CERTIFICATE_VERIFY_FAILED``. The range of possible |
| 203 | values depends on the OpenSSL version. |
| 204 | |
| 205 | .. versionadded:: 3.3 |
| 206 | |
Antoine Pitrou | 41032a6 | 2011-10-27 23:56:55 +0200 | [diff] [blame] | 207 | .. exception:: SSLZeroReturnError |
| 208 | |
| 209 | A subclass of :exc:`SSLError` raised when trying to read or write and |
| 210 | the SSL connection has been closed cleanly. Note that this doesn't |
| 211 | mean that the underlying transport (read TCP) has been closed. |
| 212 | |
| 213 | .. versionadded:: 3.3 |
| 214 | |
| 215 | .. exception:: SSLWantReadError |
| 216 | |
| 217 | A subclass of :exc:`SSLError` raised by a :ref:`non-blocking SSL socket |
| 218 | <ssl-nonblocking>` when trying to read or write data, but more data needs |
| 219 | to be received on the underlying TCP transport before the request can be |
| 220 | fulfilled. |
| 221 | |
| 222 | .. versionadded:: 3.3 |
| 223 | |
| 224 | .. exception:: SSLWantWriteError |
| 225 | |
| 226 | A subclass of :exc:`SSLError` raised by a :ref:`non-blocking SSL socket |
| 227 | <ssl-nonblocking>` when trying to read or write data, but more data needs |
| 228 | to be sent on the underlying TCP transport before the request can be |
| 229 | fulfilled. |
| 230 | |
| 231 | .. versionadded:: 3.3 |
| 232 | |
| 233 | .. exception:: SSLSyscallError |
| 234 | |
| 235 | A subclass of :exc:`SSLError` raised when a system error was encountered |
| 236 | while trying to fulfill an operation on a SSL socket. Unfortunately, |
| 237 | there is no easy way to inspect the original errno number. |
| 238 | |
| 239 | .. versionadded:: 3.3 |
| 240 | |
| 241 | .. exception:: SSLEOFError |
| 242 | |
| 243 | A subclass of :exc:`SSLError` raised when the SSL connection has been |
Antoine Pitrou | f3dc2d7 | 2011-10-28 00:01:03 +0200 | [diff] [blame] | 244 | terminated abruptly. Generally, you shouldn't try to reuse the underlying |
Antoine Pitrou | 41032a6 | 2011-10-27 23:56:55 +0200 | [diff] [blame] | 245 | transport when this error is encountered. |
| 246 | |
| 247 | .. versionadded:: 3.3 |
| 248 | |
Christian Heimes | b3ad0e5 | 2017-09-08 12:00:19 -0700 | [diff] [blame] | 249 | .. exception:: SSLCertVerificationError |
| 250 | |
| 251 | A subclass of :exc:`SSLError` raised when certificate validation has |
| 252 | failed. |
| 253 | |
| 254 | .. versionadded:: 3.7 |
| 255 | |
| 256 | .. attribute:: verify_code |
| 257 | |
| 258 | A numeric error number that denotes the verification error. |
| 259 | |
| 260 | .. attribute:: verify_message |
| 261 | |
| 262 | A human readable string of the verification error. |
| 263 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 264 | .. exception:: CertificateError |
| 265 | |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 266 | An alias for :exc:`SSLCertVerificationError`. |
| 267 | |
| 268 | .. versionchanged:: 3.7 |
| 269 | The exception is now an alias for :exc:`SSLCertVerificationError`. |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 270 | |
| 271 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 272 | Random generation |
| 273 | ^^^^^^^^^^^^^^^^^ |
| 274 | |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 275 | .. function:: RAND_bytes(num) |
| 276 | |
Benjamin Peterson | 1c69c3e | 2015-04-11 07:42:42 -0400 | [diff] [blame] | 277 | Return *num* cryptographically strong pseudo-random bytes. Raises an |
Victor Stinner | a675206 | 2011-05-25 11:27:40 +0200 | [diff] [blame] | 278 | :class:`SSLError` if the PRNG has not been seeded with enough data or if the |
| 279 | operation is not supported by the current RAND method. :func:`RAND_status` |
| 280 | can be used to check the status of the PRNG and :func:`RAND_add` can be used |
| 281 | to seed the PRNG. |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 282 | |
Berker Peksag | eb7a97c | 2015-04-10 16:19:13 +0300 | [diff] [blame] | 283 | For almost all applications :func:`os.urandom` is preferable. |
| 284 | |
Victor Stinner | 19fb53c | 2011-05-24 21:32:40 +0200 | [diff] [blame] | 285 | Read the Wikipedia article, `Cryptographically secure pseudorandom number |
Victor Stinner | a675206 | 2011-05-25 11:27:40 +0200 | [diff] [blame] | 286 | generator (CSPRNG) |
Georg Brandl | 5d94134 | 2016-02-26 19:37:12 +0100 | [diff] [blame] | 287 | <https://en.wikipedia.org/wiki/Cryptographically_secure_pseudorandom_number_generator>`_, |
Victor Stinner | 19fb53c | 2011-05-24 21:32:40 +0200 | [diff] [blame] | 288 | to get the requirements of a cryptographically generator. |
| 289 | |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 290 | .. versionadded:: 3.3 |
| 291 | |
| 292 | .. function:: RAND_pseudo_bytes(num) |
| 293 | |
Benjamin Peterson | 1c69c3e | 2015-04-11 07:42:42 -0400 | [diff] [blame] | 294 | Return (bytes, is_cryptographic): bytes are *num* pseudo-random bytes, |
Serhiy Storchaka | fbc1c26 | 2013-11-29 12:17:13 +0200 | [diff] [blame] | 295 | is_cryptographic is ``True`` if the bytes generated are cryptographically |
Victor Stinner | a675206 | 2011-05-25 11:27:40 +0200 | [diff] [blame] | 296 | strong. Raises an :class:`SSLError` if the operation is not supported by the |
| 297 | current RAND method. |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 298 | |
Victor Stinner | 19fb53c | 2011-05-24 21:32:40 +0200 | [diff] [blame] | 299 | Generated pseudo-random byte sequences will be unique if they are of |
| 300 | sufficient length, but are not necessarily unpredictable. They can be used |
| 301 | for non-cryptographic purposes and for certain purposes in cryptographic |
| 302 | protocols, but usually not for key generation etc. |
| 303 | |
Berker Peksag | eb7a97c | 2015-04-10 16:19:13 +0300 | [diff] [blame] | 304 | For almost all applications :func:`os.urandom` is preferable. |
| 305 | |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 306 | .. versionadded:: 3.3 |
| 307 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 308 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 309 | |
| 310 | OpenSSL has deprecated :func:`ssl.RAND_pseudo_bytes`, use |
| 311 | :func:`ssl.RAND_bytes` instead. |
| 312 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 313 | .. function:: RAND_status() |
| 314 | |
Benjamin Peterson | 1c69c3e | 2015-04-11 07:42:42 -0400 | [diff] [blame] | 315 | Return ``True`` if the SSL pseudo-random number generator has been seeded |
| 316 | with 'enough' randomness, and ``False`` otherwise. You can use |
| 317 | :func:`ssl.RAND_egd` and :func:`ssl.RAND_add` to increase the randomness of |
| 318 | the pseudo-random number generator. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 319 | |
| 320 | .. function:: RAND_egd(path) |
| 321 | |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 322 | If you are running an entropy-gathering daemon (EGD) somewhere, and *path* |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 323 | is the pathname of a socket connection open to it, this will read 256 bytes |
| 324 | of randomness from the socket, and add it to the SSL pseudo-random number |
| 325 | generator to increase the security of generated secret keys. This is |
| 326 | typically only necessary on systems without better sources of randomness. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 327 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 328 | See http://egd.sourceforge.net/ or http://prngd.sourceforge.net/ for sources |
| 329 | of entropy-gathering daemons. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 330 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 331 | Availability: not available with LibreSSL and OpenSSL > 1.1.0 |
Victor Stinner | 3ce67a9 | 2015-01-06 13:53:09 +0100 | [diff] [blame] | 332 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 333 | .. function:: RAND_add(bytes, entropy) |
| 334 | |
Benjamin Peterson | 1c69c3e | 2015-04-11 07:42:42 -0400 | [diff] [blame] | 335 | Mix the given *bytes* into the SSL pseudo-random number generator. The |
Victor Stinner | 99c8b16 | 2011-05-24 12:05:19 +0200 | [diff] [blame] | 336 | parameter *entropy* (a float) is a lower bound on the entropy contained in |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 337 | string (so you can always use :const:`0.0`). See :rfc:`1750` for more |
| 338 | information on sources of entropy. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 339 | |
Georg Brandl | 8c16cb9 | 2016-02-25 20:17:45 +0100 | [diff] [blame] | 340 | .. versionchanged:: 3.5 |
Serhiy Storchaka | 8490f5a | 2015-03-20 09:00:36 +0200 | [diff] [blame] | 341 | Writable :term:`bytes-like object` is now accepted. |
| 342 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 343 | Certificate handling |
| 344 | ^^^^^^^^^^^^^^^^^^^^ |
| 345 | |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 346 | .. testsetup:: |
| 347 | |
| 348 | import ssl |
| 349 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 350 | .. function:: match_hostname(cert, hostname) |
| 351 | |
| 352 | Verify that *cert* (in decoded format as returned by |
| 353 | :meth:`SSLSocket.getpeercert`) matches the given *hostname*. The rules |
| 354 | applied are those for checking the identity of HTTPS servers as outlined |
Chandan Kumar | 63c2c8a | 2017-06-09 15:13:58 +0530 | [diff] [blame] | 355 | in :rfc:`2818`, :rfc:`5280` and :rfc:`6125`. In addition to HTTPS, this |
| 356 | function should be suitable for checking the identity of servers in |
| 357 | various SSL-based protocols such as FTPS, IMAPS, POPS and others. |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 358 | |
| 359 | :exc:`CertificateError` is raised on failure. On success, the function |
| 360 | returns nothing:: |
| 361 | |
| 362 | >>> cert = {'subject': ((('commonName', 'example.com'),),)} |
| 363 | >>> ssl.match_hostname(cert, "example.com") |
| 364 | >>> ssl.match_hostname(cert, "example.org") |
| 365 | Traceback (most recent call last): |
| 366 | File "<stdin>", line 1, in <module> |
| 367 | File "/home/py3k/Lib/ssl.py", line 130, in match_hostname |
| 368 | ssl.CertificateError: hostname 'example.org' doesn't match 'example.com' |
| 369 | |
| 370 | .. versionadded:: 3.2 |
| 371 | |
Georg Brandl | 72c98d3 | 2013-10-27 07:16:53 +0100 | [diff] [blame] | 372 | .. versionchanged:: 3.3.3 |
| 373 | The function now follows :rfc:`6125`, section 6.4.3 and does neither |
| 374 | match multiple wildcards (e.g. ``*.*.com`` or ``*a*.example.org``) nor |
| 375 | a wildcard inside an internationalized domain names (IDN) fragment. |
| 376 | IDN A-labels such as ``www*.xn--pthon-kva.org`` are still supported, |
| 377 | but ``x*.python.org`` no longer matches ``xn--tda.python.org``. |
| 378 | |
Antoine Pitrou | c481bfb | 2015-02-15 18:12:20 +0100 | [diff] [blame] | 379 | .. versionchanged:: 3.5 |
| 380 | Matching of IP addresses, when present in the subjectAltName field |
| 381 | of the certificate, is now supported. |
| 382 | |
Mandeep Singh | ede2ac9 | 2017-11-27 04:01:27 +0530 | [diff] [blame] | 383 | .. versionchanged:: 3.7 |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 384 | The function is no longer used to TLS connections. Hostname matching |
| 385 | is now performed by OpenSSL. |
| 386 | |
Mandeep Singh | ede2ac9 | 2017-11-27 04:01:27 +0530 | [diff] [blame] | 387 | Allow wildcard when it is the leftmost and the only character |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 388 | in that segment. Partial wildcards like ``www*.example.com`` are no |
| 389 | longer supported. |
| 390 | |
| 391 | .. deprecated:: 3.7 |
Mandeep Singh | ede2ac9 | 2017-11-27 04:01:27 +0530 | [diff] [blame] | 392 | |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 393 | .. function:: cert_time_to_seconds(cert_time) |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 394 | |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 395 | Return the time in seconds since the Epoch, given the ``cert_time`` |
| 396 | string representing the "notBefore" or "notAfter" date from a |
| 397 | certificate in ``"%b %d %H:%M:%S %Y %Z"`` strptime format (C |
| 398 | locale). |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 399 | |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 400 | Here's an example: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 401 | |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 402 | .. doctest:: newcontext |
| 403 | |
| 404 | >>> import ssl |
| 405 | >>> timestamp = ssl.cert_time_to_seconds("Jan 5 09:34:43 2018 GMT") |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 406 | >>> timestamp # doctest: +SKIP |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 407 | 1515144883 |
| 408 | >>> from datetime import datetime |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 409 | >>> print(datetime.utcfromtimestamp(timestamp)) # doctest: +SKIP |
Antoine Pitrou | c695c95 | 2014-04-28 20:57:36 +0200 | [diff] [blame] | 410 | 2018-01-05 09:34:43 |
| 411 | |
| 412 | "notBefore" or "notAfter" dates must use GMT (:rfc:`5280`). |
| 413 | |
| 414 | .. versionchanged:: 3.5 |
| 415 | Interpret the input time as a time in UTC as specified by 'GMT' |
| 416 | timezone in the input string. Local timezone was used |
| 417 | previously. Return an integer (no fractions of a second in the |
| 418 | input format) |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 419 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 420 | .. function:: get_server_certificate(addr, ssl_version=PROTOCOL_TLS, ca_certs=None) |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 421 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 422 | Given the address ``addr`` of an SSL-protected server, as a (*hostname*, |
| 423 | *port-number*) pair, fetches the server's certificate, and returns it as a |
| 424 | PEM-encoded string. If ``ssl_version`` is specified, uses that version of |
| 425 | the SSL protocol to attempt to connect to the server. If ``ca_certs`` is |
| 426 | specified, it should be a file containing a list of root certificates, the |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 427 | same format as used for the same parameter in |
| 428 | :meth:`SSLContext.wrap_socket`. The call will attempt to validate the |
| 429 | server certificate against that set of root certificates, and will fail |
| 430 | if the validation attempt fails. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 431 | |
Antoine Pitrou | 15399c3 | 2011-04-28 19:23:55 +0200 | [diff] [blame] | 432 | .. versionchanged:: 3.3 |
| 433 | This function is now IPv6-compatible. |
| 434 | |
Antoine Pitrou | 94a5b66 | 2014-04-16 18:56:28 +0200 | [diff] [blame] | 435 | .. versionchanged:: 3.5 |
| 436 | The default *ssl_version* is changed from :data:`PROTOCOL_SSLv3` to |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 437 | :data:`PROTOCOL_TLS` for maximum compatibility with modern servers. |
Antoine Pitrou | 94a5b66 | 2014-04-16 18:56:28 +0200 | [diff] [blame] | 438 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 439 | .. function:: DER_cert_to_PEM_cert(DER_cert_bytes) |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 440 | |
| 441 | Given a certificate as a DER-encoded blob of bytes, returns a PEM-encoded |
| 442 | string version of the same certificate. |
| 443 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 444 | .. function:: PEM_cert_to_DER_cert(PEM_cert_string) |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 445 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 446 | Given a certificate as an ASCII PEM string, returns a DER-encoded sequence of |
| 447 | bytes for that same certificate. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 448 | |
Christian Heimes | 6d7ad13 | 2013-06-09 18:02:55 +0200 | [diff] [blame] | 449 | .. function:: get_default_verify_paths() |
| 450 | |
| 451 | Returns a named tuple with paths to OpenSSL's default cafile and capath. |
| 452 | The paths are the same as used by |
| 453 | :meth:`SSLContext.set_default_verify_paths`. The return value is a |
| 454 | :term:`named tuple` ``DefaultVerifyPaths``: |
| 455 | |
Serhiy Storchaka | ecf41da | 2016-10-19 16:29:26 +0300 | [diff] [blame] | 456 | * :attr:`cafile` - resolved path to cafile or ``None`` if the file doesn't exist, |
| 457 | * :attr:`capath` - resolved path to capath or ``None`` if the directory doesn't exist, |
Christian Heimes | 6d7ad13 | 2013-06-09 18:02:55 +0200 | [diff] [blame] | 458 | * :attr:`openssl_cafile_env` - OpenSSL's environment key that points to a cafile, |
| 459 | * :attr:`openssl_cafile` - hard coded path to a cafile, |
| 460 | * :attr:`openssl_capath_env` - OpenSSL's environment key that points to a capath, |
| 461 | * :attr:`openssl_capath` - hard coded path to a capath directory |
| 462 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 463 | Availability: LibreSSL ignores the environment vars |
| 464 | :attr:`openssl_cafile_env` and :attr:`openssl_capath_env` |
| 465 | |
Christian Heimes | 6d7ad13 | 2013-06-09 18:02:55 +0200 | [diff] [blame] | 466 | .. versionadded:: 3.4 |
| 467 | |
Christian Heimes | 44109d7 | 2013-11-22 01:51:30 +0100 | [diff] [blame] | 468 | .. function:: enum_certificates(store_name) |
Christian Heimes | 46bebee | 2013-06-09 19:03:31 +0200 | [diff] [blame] | 469 | |
| 470 | Retrieve certificates from Windows' system cert store. *store_name* may be |
| 471 | one of ``CA``, ``ROOT`` or ``MY``. Windows may provide additional cert |
Christian Heimes | 44109d7 | 2013-11-22 01:51:30 +0100 | [diff] [blame] | 472 | stores, too. |
Christian Heimes | 46bebee | 2013-06-09 19:03:31 +0200 | [diff] [blame] | 473 | |
Christian Heimes | 44109d7 | 2013-11-22 01:51:30 +0100 | [diff] [blame] | 474 | The function returns a list of (cert_bytes, encoding_type, trust) tuples. |
| 475 | The encoding_type specifies the encoding of cert_bytes. It is either |
| 476 | :const:`x509_asn` for X.509 ASN.1 data or :const:`pkcs_7_asn` for |
| 477 | PKCS#7 ASN.1 data. Trust specifies the purpose of the certificate as a set |
| 478 | of OIDS or exactly ``True`` if the certificate is trustworthy for all |
| 479 | purposes. |
| 480 | |
| 481 | Example:: |
| 482 | |
| 483 | >>> ssl.enum_certificates("CA") |
| 484 | [(b'data...', 'x509_asn', {'1.3.6.1.5.5.7.3.1', '1.3.6.1.5.5.7.3.2'}), |
| 485 | (b'data...', 'x509_asn', True)] |
Christian Heimes | 46bebee | 2013-06-09 19:03:31 +0200 | [diff] [blame] | 486 | |
| 487 | Availability: Windows. |
| 488 | |
| 489 | .. versionadded:: 3.4 |
Christian Heimes | 6d7ad13 | 2013-06-09 18:02:55 +0200 | [diff] [blame] | 490 | |
Christian Heimes | 44109d7 | 2013-11-22 01:51:30 +0100 | [diff] [blame] | 491 | .. function:: enum_crls(store_name) |
| 492 | |
| 493 | Retrieve CRLs from Windows' system cert store. *store_name* may be |
| 494 | one of ``CA``, ``ROOT`` or ``MY``. Windows may provide additional cert |
| 495 | stores, too. |
| 496 | |
| 497 | The function returns a list of (cert_bytes, encoding_type, trust) tuples. |
| 498 | The encoding_type specifies the encoding of cert_bytes. It is either |
| 499 | :const:`x509_asn` for X.509 ASN.1 data or :const:`pkcs_7_asn` for |
| 500 | PKCS#7 ASN.1 data. |
| 501 | |
| 502 | Availability: Windows. |
| 503 | |
| 504 | .. versionadded:: 3.4 |
| 505 | |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 506 | .. function:: wrap_socket(sock, keyfile=None, certfile=None, \ |
| 507 | server_side=False, cert_reqs=CERT_NONE, ssl_version=PROTOCOL_TLS, \ |
| 508 | ca_certs=None, do_handshake_on_connect=True, \ |
| 509 | suppress_ragged_eofs=True, ciphers=None) |
| 510 | |
| 511 | Takes an instance ``sock`` of :class:`socket.socket`, and returns an instance |
| 512 | of :class:`ssl.SSLSocket`, a subtype of :class:`socket.socket`, which wraps |
| 513 | the underlying socket in an SSL context. ``sock`` must be a |
| 514 | :data:`~socket.SOCK_STREAM` socket; other socket types are unsupported. |
| 515 | |
| 516 | Internally, function creates a :class:`SSLContext` with protocol |
| 517 | *ssl_version* and :attr:`SSLContext.options` set to *cert_reqs*. If |
| 518 | parameters *keyfile*, *certfile*, *ca_certs* or *ciphers* are set, then |
| 519 | the values are passed to :meth:`SSLContext.load_cert_chain`, |
| 520 | :meth:`SSLContext.load_verify_locations`, and |
| 521 | :meth:`SSLContext.set_ciphers`. |
| 522 | |
| 523 | The arguments *server_side*, *do_handshake_on_connect*, and |
| 524 | *suppress_ragged_eofs* have the same meaning as |
| 525 | :meth:`SSLContext.wrap_socket`. |
| 526 | |
| 527 | .. deprecated:: 3.7 |
| 528 | |
| 529 | Since Python 3.2 and 2.7.9, it is recommended to use the |
| 530 | :meth:`SSLContext.wrap_socket` instead of :func:`wrap_socket`. The |
| 531 | top-level function is limited and creates an insecure client socket |
| 532 | without server name indication or hostname matching. |
Christian Heimes | 44109d7 | 2013-11-22 01:51:30 +0100 | [diff] [blame] | 533 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 534 | Constants |
| 535 | ^^^^^^^^^ |
| 536 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 537 | All constants are now :class:`enum.IntEnum` or :class:`enum.IntFlag` collections. |
| 538 | |
| 539 | .. versionadded:: 3.6 |
| 540 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 541 | .. data:: CERT_NONE |
| 542 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 543 | Possible value for :attr:`SSLContext.verify_mode`, or the ``cert_reqs`` |
Christian Heimes | ef24b6c | 2018-06-12 00:59:45 +0200 | [diff] [blame] | 544 | parameter to :func:`wrap_socket`. Except for :const:`PROTOCOL_TLS_CLIENT`, |
| 545 | it is the default mode. With client-side sockets, just about any |
| 546 | cert is accepted. Validation errors, such as untrusted or expired cert, |
| 547 | are ignored and do not abort the TLS/SSL handshake. |
| 548 | |
| 549 | In server mode, no certificate is requested from the client, so the client |
| 550 | does not send any for client cert authentication. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 551 | |
| 552 | See the discussion of :ref:`ssl-security` below. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 553 | |
| 554 | .. data:: CERT_OPTIONAL |
| 555 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 556 | Possible value for :attr:`SSLContext.verify_mode`, or the ``cert_reqs`` |
Christian Heimes | ef24b6c | 2018-06-12 00:59:45 +0200 | [diff] [blame] | 557 | parameter to :func:`wrap_socket`. In client mode, :const:`CERT_OPTIONAL` |
| 558 | has the same meaning as :const:`CERT_REQUIRED`. It is recommended to |
| 559 | use :const:`CERT_REQUIRED` for client-side sockets instead. |
| 560 | |
| 561 | In server mode, a client certificate request is sent to the client. The |
| 562 | client may either ignore the request or send a certificate in order |
| 563 | perform TLS client cert authentication. If the client chooses to send |
| 564 | a certificate, it is verified. Any verification error immediately aborts |
| 565 | the TLS handshake. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 566 | |
| 567 | Use of this setting requires a valid set of CA certificates to |
| 568 | be passed, either to :meth:`SSLContext.load_verify_locations` or as a |
| 569 | value of the ``ca_certs`` parameter to :func:`wrap_socket`. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 570 | |
| 571 | .. data:: CERT_REQUIRED |
| 572 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 573 | Possible value for :attr:`SSLContext.verify_mode`, or the ``cert_reqs`` |
| 574 | parameter to :func:`wrap_socket`. In this mode, certificates are |
| 575 | required from the other side of the socket connection; an :class:`SSLError` |
| 576 | will be raised if no certificate is provided, or if its validation fails. |
Christian Heimes | ef24b6c | 2018-06-12 00:59:45 +0200 | [diff] [blame] | 577 | This mode is **not** sufficient to verify a certificate in client mode as |
| 578 | it does not match hostnames. :attr:`~SSLContext.check_hostname` must be |
| 579 | enabled as well to verify the authenticity of a cert. |
| 580 | :const:`PROTOCOL_TLS_CLIENT` uses :const:`CERT_REQUIRED` and |
| 581 | enables :attr:`~SSLContext.check_hostname` by default. |
| 582 | |
| 583 | With server socket, this mode provides mandatory TLS client cert |
| 584 | authentication. A client certificate request is sent to the client and |
| 585 | the client must provide a valid and trusted certificate. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 586 | |
| 587 | Use of this setting requires a valid set of CA certificates to |
| 588 | be passed, either to :meth:`SSLContext.load_verify_locations` or as a |
| 589 | value of the ``ca_certs`` parameter to :func:`wrap_socket`. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 590 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 591 | .. class:: VerifyMode |
| 592 | |
| 593 | :class:`enum.IntEnum` collection of CERT_* constants. |
| 594 | |
| 595 | .. versionadded:: 3.6 |
| 596 | |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 597 | .. data:: VERIFY_DEFAULT |
| 598 | |
Benjamin Peterson | 990fcaa | 2015-03-04 22:49:41 -0500 | [diff] [blame] | 599 | Possible value for :attr:`SSLContext.verify_flags`. In this mode, certificate |
| 600 | revocation lists (CRLs) are not checked. By default OpenSSL does neither |
| 601 | require nor verify CRLs. |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 602 | |
| 603 | .. versionadded:: 3.4 |
| 604 | |
| 605 | .. data:: VERIFY_CRL_CHECK_LEAF |
| 606 | |
| 607 | Possible value for :attr:`SSLContext.verify_flags`. In this mode, only the |
| 608 | peer cert is check but non of the intermediate CA certificates. The mode |
| 609 | requires a valid CRL that is signed by the peer cert's issuer (its direct |
| 610 | ancestor CA). If no proper has been loaded |
| 611 | :attr:`SSLContext.load_verify_locations`, validation will fail. |
| 612 | |
| 613 | .. versionadded:: 3.4 |
| 614 | |
| 615 | .. data:: VERIFY_CRL_CHECK_CHAIN |
| 616 | |
| 617 | Possible value for :attr:`SSLContext.verify_flags`. In this mode, CRLs of |
| 618 | all certificates in the peer cert chain are checked. |
| 619 | |
| 620 | .. versionadded:: 3.4 |
| 621 | |
| 622 | .. data:: VERIFY_X509_STRICT |
| 623 | |
| 624 | Possible value for :attr:`SSLContext.verify_flags` to disable workarounds |
| 625 | for broken X.509 certificates. |
| 626 | |
| 627 | .. versionadded:: 3.4 |
| 628 | |
Benjamin Peterson | 990fcaa | 2015-03-04 22:49:41 -0500 | [diff] [blame] | 629 | .. data:: VERIFY_X509_TRUSTED_FIRST |
| 630 | |
| 631 | Possible value for :attr:`SSLContext.verify_flags`. It instructs OpenSSL to |
| 632 | prefer trusted certificates when building the trust chain to validate a |
| 633 | certificate. This flag is enabled by default. |
| 634 | |
Benjamin Peterson | c835827 | 2015-03-08 09:42:25 -0400 | [diff] [blame] | 635 | .. versionadded:: 3.4.4 |
Benjamin Peterson | 990fcaa | 2015-03-04 22:49:41 -0500 | [diff] [blame] | 636 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 637 | .. class:: VerifyFlags |
| 638 | |
| 639 | :class:`enum.IntFlag` collection of VERIFY_* constants. |
| 640 | |
| 641 | .. versionadded:: 3.6 |
| 642 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 643 | .. data:: PROTOCOL_TLS |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 644 | |
| 645 | Selects the highest protocol version that both the client and server support. |
Nathaniel J. Smith | d4069de | 2017-05-01 22:43:31 -0700 | [diff] [blame] | 646 | Despite the name, this option can select both "SSL" and "TLS" protocols. |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 647 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 648 | .. versionadded:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 649 | |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 650 | .. data:: PROTOCOL_TLS_CLIENT |
| 651 | |
Nathaniel J. Smith | d4069de | 2017-05-01 22:43:31 -0700 | [diff] [blame] | 652 | Auto-negotiate the highest protocol version like :data:`PROTOCOL_TLS`, |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 653 | but only support client-side :class:`SSLSocket` connections. The protocol |
| 654 | enables :data:`CERT_REQUIRED` and :attr:`~SSLContext.check_hostname` by |
| 655 | default. |
| 656 | |
| 657 | .. versionadded:: 3.6 |
| 658 | |
| 659 | .. data:: PROTOCOL_TLS_SERVER |
| 660 | |
Nathaniel J. Smith | d4069de | 2017-05-01 22:43:31 -0700 | [diff] [blame] | 661 | Auto-negotiate the highest protocol version like :data:`PROTOCOL_TLS`, |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 662 | but only support server-side :class:`SSLSocket` connections. |
| 663 | |
| 664 | .. versionadded:: 3.6 |
| 665 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 666 | .. data:: PROTOCOL_SSLv23 |
| 667 | |
| 668 | Alias for data:`PROTOCOL_TLS`. |
| 669 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 670 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 671 | |
Berker Peksag | d93c4de | 2017-02-06 13:37:19 +0300 | [diff] [blame] | 672 | Use :data:`PROTOCOL_TLS` instead. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 673 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 674 | .. data:: PROTOCOL_SSLv2 |
| 675 | |
| 676 | Selects SSL version 2 as the channel encryption protocol. |
| 677 | |
Benjamin Peterson | b92fd01 | 2014-12-06 11:36:32 -0500 | [diff] [blame] | 678 | This protocol is not available if OpenSSL is compiled with the |
| 679 | ``OPENSSL_NO_SSL2`` flag. |
Victor Stinner | 3de4919 | 2011-05-09 00:42:58 +0200 | [diff] [blame] | 680 | |
Antoine Pitrou | 8eac60d | 2010-05-16 14:19:41 +0000 | [diff] [blame] | 681 | .. warning:: |
| 682 | |
| 683 | SSL version 2 is insecure. Its use is highly discouraged. |
| 684 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 685 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 686 | |
| 687 | OpenSSL has removed support for SSLv2. |
| 688 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 689 | .. data:: PROTOCOL_SSLv3 |
| 690 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 691 | Selects SSL version 3 as the channel encryption protocol. |
| 692 | |
Benjamin Peterson | b92fd01 | 2014-12-06 11:36:32 -0500 | [diff] [blame] | 693 | This protocol is not be available if OpenSSL is compiled with the |
| 694 | ``OPENSSL_NO_SSLv3`` flag. |
| 695 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 696 | .. warning:: |
| 697 | |
| 698 | SSL version 3 is insecure. Its use is highly discouraged. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 699 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 700 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 701 | |
| 702 | OpenSSL has deprecated all version specific protocols. Use the default |
Berker Peksag | d93c4de | 2017-02-06 13:37:19 +0300 | [diff] [blame] | 703 | protocol :data:`PROTOCOL_TLS` with flags like :data:`OP_NO_SSLv3` instead. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 704 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 705 | .. data:: PROTOCOL_TLSv1 |
| 706 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 707 | Selects TLS version 1.0 as the channel encryption protocol. |
| 708 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 709 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 710 | |
| 711 | OpenSSL has deprecated all version specific protocols. Use the default |
Berker Peksag | d93c4de | 2017-02-06 13:37:19 +0300 | [diff] [blame] | 712 | protocol :data:`PROTOCOL_TLS` with flags like :data:`OP_NO_SSLv3` instead. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 713 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 714 | .. data:: PROTOCOL_TLSv1_1 |
| 715 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 716 | Selects TLS version 1.1 as the channel encryption protocol. |
| 717 | Available only with openssl version 1.0.1+. |
| 718 | |
| 719 | .. versionadded:: 3.4 |
| 720 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 721 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 722 | |
| 723 | OpenSSL has deprecated all version specific protocols. Use the default |
Berker Peksag | d93c4de | 2017-02-06 13:37:19 +0300 | [diff] [blame] | 724 | protocol :data:`PROTOCOL_TLS` with flags like :data:`OP_NO_SSLv3` instead. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 725 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 726 | .. data:: PROTOCOL_TLSv1_2 |
| 727 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 728 | Selects TLS version 1.2 as the channel encryption protocol. This is the |
| 729 | most modern version, and probably the best choice for maximum protection, |
| 730 | if both sides can speak it. Available only with openssl version 1.0.1+. |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 731 | |
| 732 | .. versionadded:: 3.4 |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 733 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 734 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 735 | |
| 736 | OpenSSL has deprecated all version specific protocols. Use the default |
Berker Peksag | d93c4de | 2017-02-06 13:37:19 +0300 | [diff] [blame] | 737 | protocol :data:`PROTOCOL_TLS` with flags like :data:`OP_NO_SSLv3` instead. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 738 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 739 | .. data:: OP_ALL |
| 740 | |
| 741 | Enables workarounds for various bugs present in other SSL implementations. |
Antoine Pitrou | 9f6b02e | 2012-01-27 10:02:55 +0100 | [diff] [blame] | 742 | This option is set by default. It does not necessarily set the same |
| 743 | flags as OpenSSL's ``SSL_OP_ALL`` constant. |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 744 | |
| 745 | .. versionadded:: 3.2 |
| 746 | |
| 747 | .. data:: OP_NO_SSLv2 |
| 748 | |
| 749 | Prevents an SSLv2 connection. This option is only applicable in |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 750 | conjunction with :const:`PROTOCOL_TLS`. It prevents the peers from |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 751 | choosing SSLv2 as the protocol version. |
| 752 | |
| 753 | .. versionadded:: 3.2 |
| 754 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 755 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 756 | |
| 757 | SSLv2 is deprecated |
| 758 | |
| 759 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 760 | .. data:: OP_NO_SSLv3 |
| 761 | |
| 762 | Prevents an SSLv3 connection. This option is only applicable in |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 763 | conjunction with :const:`PROTOCOL_TLS`. It prevents the peers from |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 764 | choosing SSLv3 as the protocol version. |
| 765 | |
| 766 | .. versionadded:: 3.2 |
| 767 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 768 | .. deprecated:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 769 | |
| 770 | SSLv3 is deprecated |
| 771 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 772 | .. data:: OP_NO_TLSv1 |
| 773 | |
| 774 | Prevents a TLSv1 connection. This option is only applicable in |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 775 | conjunction with :const:`PROTOCOL_TLS`. It prevents the peers from |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 776 | choosing TLSv1 as the protocol version. |
| 777 | |
| 778 | .. versionadded:: 3.2 |
| 779 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 780 | .. deprecated:: 3.7 |
| 781 | The option is deprecated since OpenSSL 1.1.0, use the new |
| 782 | :attr:`SSLContext.minimum_version` and |
| 783 | :attr:`SSLContext.maximum_version` instead. |
| 784 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 785 | .. data:: OP_NO_TLSv1_1 |
| 786 | |
| 787 | Prevents a TLSv1.1 connection. This option is only applicable in conjunction |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 788 | with :const:`PROTOCOL_TLS`. It prevents the peers from choosing TLSv1.1 as |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 789 | the protocol version. Available only with openssl version 1.0.1+. |
| 790 | |
| 791 | .. versionadded:: 3.4 |
| 792 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 793 | .. deprecated:: 3.7 |
| 794 | The option is deprecated since OpenSSL 1.1.0. |
| 795 | |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 796 | .. data:: OP_NO_TLSv1_2 |
| 797 | |
| 798 | Prevents a TLSv1.2 connection. This option is only applicable in conjunction |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 799 | with :const:`PROTOCOL_TLS`. It prevents the peers from choosing TLSv1.2 as |
Antoine Pitrou | 2463e5f | 2013-03-28 22:24:43 +0100 | [diff] [blame] | 800 | the protocol version. Available only with openssl version 1.0.1+. |
| 801 | |
| 802 | .. versionadded:: 3.4 |
| 803 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 804 | .. deprecated:: 3.7 |
| 805 | The option is deprecated since OpenSSL 1.1.0. |
| 806 | |
Christian Heimes | cb5b68a | 2017-09-07 18:07:00 -0700 | [diff] [blame] | 807 | .. data:: OP_NO_TLSv1_3 |
| 808 | |
| 809 | Prevents a TLSv1.3 connection. This option is only applicable in conjunction |
| 810 | with :const:`PROTOCOL_TLS`. It prevents the peers from choosing TLSv1.3 as |
| 811 | the protocol version. TLS 1.3 is available with OpenSSL 1.1.1 or later. |
| 812 | When Python has been compiled against an older version of OpenSSL, the |
| 813 | flag defaults to *0*. |
| 814 | |
| 815 | .. versionadded:: 3.7 |
| 816 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 817 | .. deprecated:: 3.7 |
| 818 | The option is deprecated since OpenSSL 1.1.0. It was added to 2.7.15, |
| 819 | 3.6.3 and 3.7.0 for backwards compatibility with OpenSSL 1.0.2. |
| 820 | |
Christian Heimes | 67c4801 | 2018-05-15 16:25:40 -0400 | [diff] [blame] | 821 | .. data:: OP_NO_RENEGOTIATION |
| 822 | |
| 823 | Disable all renegotiation in TLSv1.2 and earlier. Do not send |
| 824 | HelloRequest messages, and ignore renegotiation requests via ClientHello. |
| 825 | |
| 826 | This option is only available with OpenSSL 1.1.0h and later. |
| 827 | |
| 828 | .. versionadded:: 3.7 |
| 829 | |
Antoine Pitrou | 6db4944 | 2011-12-19 13:27:11 +0100 | [diff] [blame] | 830 | .. data:: OP_CIPHER_SERVER_PREFERENCE |
| 831 | |
| 832 | Use the server's cipher ordering preference, rather than the client's. |
| 833 | This option has no effect on client sockets and SSLv2 server sockets. |
| 834 | |
| 835 | .. versionadded:: 3.3 |
| 836 | |
Antoine Pitrou | 0e576f1 | 2011-12-22 10:03:38 +0100 | [diff] [blame] | 837 | .. data:: OP_SINGLE_DH_USE |
| 838 | |
| 839 | Prevents re-use of the same DH key for distinct SSL sessions. This |
| 840 | improves forward secrecy but requires more computational resources. |
| 841 | This option only applies to server sockets. |
| 842 | |
| 843 | .. versionadded:: 3.3 |
| 844 | |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 845 | .. data:: OP_SINGLE_ECDH_USE |
| 846 | |
Antoine Pitrou | 0e576f1 | 2011-12-22 10:03:38 +0100 | [diff] [blame] | 847 | Prevents re-use of the same ECDH key for distinct SSL sessions. This |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 848 | improves forward secrecy but requires more computational resources. |
| 849 | This option only applies to server sockets. |
| 850 | |
| 851 | .. versionadded:: 3.3 |
| 852 | |
Christian Heimes | 05d9fe3 | 2018-02-27 08:55:39 +0100 | [diff] [blame] | 853 | .. data:: OP_ENABLE_MIDDLEBOX_COMPAT |
| 854 | |
| 855 | Send dummy Change Cipher Spec (CCS) messages in TLS 1.3 handshake to make |
| 856 | a TLS 1.3 connection look more like a TLS 1.2 connection. |
| 857 | |
| 858 | This option is only available with OpenSSL 1.1.1 and later. |
| 859 | |
| 860 | .. versionadded:: 3.8 |
| 861 | |
Antoine Pitrou | 8abdb8a | 2011-12-20 10:13:40 +0100 | [diff] [blame] | 862 | .. data:: OP_NO_COMPRESSION |
| 863 | |
| 864 | Disable compression on the SSL channel. This is useful if the application |
| 865 | protocol supports its own compression scheme. |
| 866 | |
| 867 | This option is only available with OpenSSL 1.0.0 and later. |
| 868 | |
| 869 | .. versionadded:: 3.3 |
| 870 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 871 | .. class:: Options |
| 872 | |
| 873 | :class:`enum.IntFlag` collection of OP_* constants. |
| 874 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 875 | .. data:: OP_NO_TICKET |
| 876 | |
| 877 | Prevent client side from requesting a session ticket. |
| 878 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 879 | .. versionadded:: 3.6 |
| 880 | |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 881 | .. data:: HAS_ALPN |
| 882 | |
| 883 | Whether the OpenSSL library has built-in support for the *Application-Layer |
| 884 | Protocol Negotiation* TLS extension as described in :rfc:`7301`. |
| 885 | |
| 886 | .. versionadded:: 3.5 |
| 887 | |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 888 | .. data:: HAS_NEVER_CHECK_COMMON_NAME |
| 889 | |
| 890 | Whether the OpenSSL library has built-in support not checking subject |
| 891 | common name and :attr:`SSLContext.hostname_checks_common_name` is |
| 892 | writeable. |
| 893 | |
| 894 | .. versionadded:: 3.7 |
| 895 | |
Antoine Pitrou | 501da61 | 2011-12-21 09:27:41 +0100 | [diff] [blame] | 896 | .. data:: HAS_ECDH |
| 897 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 898 | Whether the OpenSSL library has built-in support for the Elliptic Curve-based |
Antoine Pitrou | 501da61 | 2011-12-21 09:27:41 +0100 | [diff] [blame] | 899 | Diffie-Hellman key exchange. This should be true unless the feature was |
| 900 | explicitly disabled by the distributor. |
| 901 | |
| 902 | .. versionadded:: 3.3 |
| 903 | |
Antoine Pitrou | d532321 | 2010-10-22 18:19:07 +0000 | [diff] [blame] | 904 | .. data:: HAS_SNI |
| 905 | |
| 906 | Whether the OpenSSL library has built-in support for the *Server Name |
Chandan Kumar | 63c2c8a | 2017-06-09 15:13:58 +0530 | [diff] [blame] | 907 | Indication* extension (as defined in :rfc:`6066`). |
Antoine Pitrou | d532321 | 2010-10-22 18:19:07 +0000 | [diff] [blame] | 908 | |
| 909 | .. versionadded:: 3.2 |
| 910 | |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 911 | .. data:: HAS_NPN |
| 912 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 913 | Whether the OpenSSL library has built-in support for the *Next Protocol |
Sanyam Khurana | 338cd83 | 2018-01-20 05:55:37 +0530 | [diff] [blame] | 914 | Negotiation* as described in the `Application Layer Protocol |
| 915 | Negotiation <https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation>`_. |
| 916 | When true, you can use the :meth:`SSLContext.set_npn_protocols` method to advertise |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 917 | which protocols you want to support. |
| 918 | |
| 919 | .. versionadded:: 3.3 |
| 920 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 921 | .. data:: HAS_SSLv2 |
| 922 | |
| 923 | Whether the OpenSSL library has built-in support for the SSL 2.0 protocol. |
| 924 | |
| 925 | .. versionadded:: 3.7 |
| 926 | |
| 927 | .. data:: HAS_SSLv3 |
| 928 | |
| 929 | Whether the OpenSSL library has built-in support for the SSL 3.0 protocol. |
| 930 | |
| 931 | .. versionadded:: 3.7 |
| 932 | |
| 933 | .. data:: HAS_TLSv1 |
| 934 | |
| 935 | Whether the OpenSSL library has built-in support for the TLS 1.0 protocol. |
| 936 | |
| 937 | .. versionadded:: 3.7 |
| 938 | |
| 939 | .. data:: HAS_TLSv1_1 |
| 940 | |
| 941 | Whether the OpenSSL library has built-in support for the TLS 1.1 protocol. |
| 942 | |
| 943 | .. versionadded:: 3.7 |
| 944 | |
| 945 | .. data:: HAS_TLSv1_2 |
| 946 | |
| 947 | Whether the OpenSSL library has built-in support for the TLS 1.2 protocol. |
| 948 | |
| 949 | .. versionadded:: 3.7 |
| 950 | |
Christian Heimes | cb5b68a | 2017-09-07 18:07:00 -0700 | [diff] [blame] | 951 | .. data:: HAS_TLSv1_3 |
| 952 | |
| 953 | Whether the OpenSSL library has built-in support for the TLS 1.3 protocol. |
| 954 | |
| 955 | .. versionadded:: 3.7 |
| 956 | |
Antoine Pitrou | d649480 | 2011-07-21 01:11:30 +0200 | [diff] [blame] | 957 | .. data:: CHANNEL_BINDING_TYPES |
| 958 | |
| 959 | List of supported TLS channel binding types. Strings in this list |
| 960 | can be used as arguments to :meth:`SSLSocket.get_channel_binding`. |
| 961 | |
| 962 | .. versionadded:: 3.3 |
| 963 | |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 964 | .. data:: OPENSSL_VERSION |
| 965 | |
| 966 | The version string of the OpenSSL library loaded by the interpreter:: |
| 967 | |
| 968 | >>> ssl.OPENSSL_VERSION |
Alex Gaynor | 275104e | 2017-03-02 05:23:19 -0500 | [diff] [blame] | 969 | 'OpenSSL 1.0.2k 26 Jan 2017' |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 970 | |
Antoine Pitrou | 43a94c31 | 2010-04-05 21:44:48 +0000 | [diff] [blame] | 971 | .. versionadded:: 3.2 |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 972 | |
| 973 | .. data:: OPENSSL_VERSION_INFO |
| 974 | |
| 975 | A tuple of five integers representing version information about the |
| 976 | OpenSSL library:: |
| 977 | |
| 978 | >>> ssl.OPENSSL_VERSION_INFO |
Alex Gaynor | 275104e | 2017-03-02 05:23:19 -0500 | [diff] [blame] | 979 | (1, 0, 2, 11, 15) |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 980 | |
Antoine Pitrou | 43a94c31 | 2010-04-05 21:44:48 +0000 | [diff] [blame] | 981 | .. versionadded:: 3.2 |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 982 | |
| 983 | .. data:: OPENSSL_VERSION_NUMBER |
| 984 | |
| 985 | The raw version number of the OpenSSL library, as a single integer:: |
| 986 | |
| 987 | >>> ssl.OPENSSL_VERSION_NUMBER |
Alex Gaynor | 275104e | 2017-03-02 05:23:19 -0500 | [diff] [blame] | 988 | 268443839 |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 989 | >>> hex(ssl.OPENSSL_VERSION_NUMBER) |
Alex Gaynor | 275104e | 2017-03-02 05:23:19 -0500 | [diff] [blame] | 990 | '0x100020bf' |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 991 | |
Antoine Pitrou | 43a94c31 | 2010-04-05 21:44:48 +0000 | [diff] [blame] | 992 | .. versionadded:: 3.2 |
Antoine Pitrou | 04f6a32 | 2010-04-05 21:40:07 +0000 | [diff] [blame] | 993 | |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 994 | .. data:: ALERT_DESCRIPTION_HANDSHAKE_FAILURE |
| 995 | ALERT_DESCRIPTION_INTERNAL_ERROR |
| 996 | ALERT_DESCRIPTION_* |
| 997 | |
| 998 | Alert Descriptions from :rfc:`5246` and others. The `IANA TLS Alert Registry |
Serhiy Storchaka | 6dff020 | 2016-05-07 10:49:07 +0300 | [diff] [blame] | 999 | <https://www.iana.org/assignments/tls-parameters/tls-parameters.xml#tls-parameters-6>`_ |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1000 | contains this list and references to the RFCs where their meaning is defined. |
| 1001 | |
| 1002 | Used as the return value of the callback function in |
| 1003 | :meth:`SSLContext.set_servername_callback`. |
| 1004 | |
| 1005 | .. versionadded:: 3.4 |
| 1006 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1007 | .. class:: AlertDescription |
| 1008 | |
| 1009 | :class:`enum.IntEnum` collection of ALERT_DESCRIPTION_* constants. |
| 1010 | |
| 1011 | .. versionadded:: 3.6 |
| 1012 | |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1013 | .. data:: Purpose.SERVER_AUTH |
| 1014 | |
Antoine Pitrou | 5bef410 | 2013-11-23 16:16:29 +0100 | [diff] [blame] | 1015 | Option for :func:`create_default_context` and |
| 1016 | :meth:`SSLContext.load_default_certs`. This value indicates that the |
| 1017 | context may be used to authenticate Web servers (therefore, it will |
| 1018 | be used to create client-side sockets). |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1019 | |
| 1020 | .. versionadded:: 3.4 |
| 1021 | |
Christian Heimes | 6b2ff98 | 2013-11-23 14:42:01 +0100 | [diff] [blame] | 1022 | .. data:: Purpose.CLIENT_AUTH |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1023 | |
Antoine Pitrou | 5bef410 | 2013-11-23 16:16:29 +0100 | [diff] [blame] | 1024 | Option for :func:`create_default_context` and |
| 1025 | :meth:`SSLContext.load_default_certs`. This value indicates that the |
| 1026 | context may be used to authenticate Web clients (therefore, it will |
| 1027 | be used to create server-side sockets). |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1028 | |
| 1029 | .. versionadded:: 3.4 |
| 1030 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1031 | .. class:: SSLErrorNumber |
| 1032 | |
| 1033 | :class:`enum.IntEnum` collection of SSL_ERROR_* constants. |
| 1034 | |
| 1035 | .. versionadded:: 3.6 |
| 1036 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 1037 | .. class:: TLSVersion |
| 1038 | |
| 1039 | :class:`enum.IntEnum` collection of SSL and TLS versions for |
| 1040 | :attr:`SSLContext.maximum_version` and :attr:`SSLContext.minimum_version`. |
| 1041 | |
| 1042 | .. versionadded:: 3.7 |
| 1043 | |
| 1044 | .. attribute:: TLSVersion.MINIMUM_SUPPORTED |
| 1045 | .. attribute:: TLSVersion.MAXIMUM_SUPPORTED |
| 1046 | |
| 1047 | The minimum or maximum supported SSL or TLS version. These are magic |
| 1048 | constants. Their values don't reflect the lowest and highest available |
| 1049 | TLS/SSL versions. |
| 1050 | |
| 1051 | .. attribute:: TLSVersion.SSLv3 |
| 1052 | .. attribute:: TLSVersion.TLSv1 |
| 1053 | .. attribute:: TLSVersion.TLSv1_1 |
| 1054 | .. attribute:: TLSVersion.TLSv1_2 |
| 1055 | .. attribute:: TLSVersion.TLSv1_3 |
| 1056 | |
| 1057 | SSL 3.0 to TLS 1.3. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 1058 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1059 | SSL Sockets |
| 1060 | ----------- |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1061 | |
Victor Stinner | 3c3d3c7 | 2014-10-10 12:06:51 +0200 | [diff] [blame] | 1062 | .. class:: SSLSocket(socket.socket) |
Antoine Pitrou | 792ff3e | 2010-09-19 13:19:21 +0000 | [diff] [blame] | 1063 | |
Victor Stinner | 3c3d3c7 | 2014-10-10 12:06:51 +0200 | [diff] [blame] | 1064 | SSL sockets provide the following methods of :ref:`socket-objects`: |
Zachary Ware | ba9fb0d | 2014-06-11 15:02:25 -0500 | [diff] [blame] | 1065 | |
Victor Stinner | 3c3d3c7 | 2014-10-10 12:06:51 +0200 | [diff] [blame] | 1066 | - :meth:`~socket.socket.accept()` |
| 1067 | - :meth:`~socket.socket.bind()` |
| 1068 | - :meth:`~socket.socket.close()` |
| 1069 | - :meth:`~socket.socket.connect()` |
| 1070 | - :meth:`~socket.socket.detach()` |
| 1071 | - :meth:`~socket.socket.fileno()` |
| 1072 | - :meth:`~socket.socket.getpeername()`, :meth:`~socket.socket.getsockname()` |
| 1073 | - :meth:`~socket.socket.getsockopt()`, :meth:`~socket.socket.setsockopt()` |
| 1074 | - :meth:`~socket.socket.gettimeout()`, :meth:`~socket.socket.settimeout()`, |
| 1075 | :meth:`~socket.socket.setblocking()` |
| 1076 | - :meth:`~socket.socket.listen()` |
| 1077 | - :meth:`~socket.socket.makefile()` |
| 1078 | - :meth:`~socket.socket.recv()`, :meth:`~socket.socket.recv_into()` |
| 1079 | (but passing a non-zero ``flags`` argument is not allowed) |
| 1080 | - :meth:`~socket.socket.send()`, :meth:`~socket.socket.sendall()` (with |
| 1081 | the same limitation) |
Victor Stinner | 92127a5 | 2014-10-10 12:43:17 +0200 | [diff] [blame] | 1082 | - :meth:`~socket.socket.sendfile()` (but :mod:`os.sendfile` will be used |
| 1083 | for plain-text sockets only, else :meth:`~socket.socket.send()` will be used) |
Victor Stinner | 3c3d3c7 | 2014-10-10 12:06:51 +0200 | [diff] [blame] | 1084 | - :meth:`~socket.socket.shutdown()` |
Zachary Ware | ba9fb0d | 2014-06-11 15:02:25 -0500 | [diff] [blame] | 1085 | |
Victor Stinner | 3c3d3c7 | 2014-10-10 12:06:51 +0200 | [diff] [blame] | 1086 | However, since the SSL (and TLS) protocol has its own framing atop |
| 1087 | of TCP, the SSL sockets abstraction can, in certain respects, diverge from |
| 1088 | the specification of normal, OS-level sockets. See especially the |
| 1089 | :ref:`notes on non-blocking sockets <ssl-nonblocking>`. |
Antoine Pitrou | e1f2f30 | 2010-09-19 13:56:11 +0000 | [diff] [blame] | 1090 | |
Christian Heimes | 9d50ab5 | 2018-02-27 10:17:30 +0100 | [diff] [blame] | 1091 | Instances of :class:`SSLSocket` must be created using the |
Alex Gaynor | 1cf2a80 | 2017-02-28 22:26:56 -0500 | [diff] [blame] | 1092 | :meth:`SSLContext.wrap_socket` method. |
Victor Stinner | d28fe8c | 2014-10-10 12:07:19 +0200 | [diff] [blame] | 1093 | |
Victor Stinner | 92127a5 | 2014-10-10 12:43:17 +0200 | [diff] [blame] | 1094 | .. versionchanged:: 3.5 |
| 1095 | The :meth:`sendfile` method was added. |
| 1096 | |
Victor Stinner | 1469070 | 2015-04-06 22:46:13 +0200 | [diff] [blame] | 1097 | .. versionchanged:: 3.5 |
| 1098 | The :meth:`shutdown` does not reset the socket timeout each time bytes |
| 1099 | are received or sent. The socket timeout is now to maximum total duration |
| 1100 | of the shutdown. |
| 1101 | |
Christian Heimes | d048637 | 2016-09-10 23:23:33 +0200 | [diff] [blame] | 1102 | .. deprecated:: 3.6 |
| 1103 | It is deprecated to create a :class:`SSLSocket` instance directly, use |
| 1104 | :meth:`SSLContext.wrap_socket` to wrap a socket. |
| 1105 | |
Christian Heimes | 9d50ab5 | 2018-02-27 10:17:30 +0100 | [diff] [blame] | 1106 | .. versionchanged:: 3.7 |
| 1107 | :class:`SSLSocket` instances must to created with |
| 1108 | :meth:`~SSLContext.wrap_socket`. In earlier versions, it was possible |
| 1109 | to create instances directly. This was never documented or officially |
| 1110 | supported. |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 1111 | |
| 1112 | SSL sockets also have the following additional methods and attributes: |
Antoine Pitrou | 792ff3e | 2010-09-19 13:19:21 +0000 | [diff] [blame] | 1113 | |
Martin Panter | f6b1d66 | 2016-03-28 00:22:09 +0000 | [diff] [blame] | 1114 | .. method:: SSLSocket.read(len=1024, buffer=None) |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1115 | |
| 1116 | Read up to *len* bytes of data from the SSL socket and return the result as |
| 1117 | a ``bytes`` instance. If *buffer* is specified, then read into the buffer |
| 1118 | instead, and return the number of bytes read. |
| 1119 | |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1120 | Raise :exc:`SSLWantReadError` or :exc:`SSLWantWriteError` if the socket is |
Victor Stinner | cfb2a0a | 2014-10-10 12:45:10 +0200 | [diff] [blame] | 1121 | :ref:`non-blocking <ssl-nonblocking>` and the read would block. |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1122 | |
| 1123 | As at any time a re-negotiation is possible, a call to :meth:`read` can also |
| 1124 | cause write operations. |
| 1125 | |
Victor Stinner | 1469070 | 2015-04-06 22:46:13 +0200 | [diff] [blame] | 1126 | .. versionchanged:: 3.5 |
| 1127 | The socket timeout is no more reset each time bytes are received or sent. |
| 1128 | The socket timeout is now to maximum total duration to read up to *len* |
| 1129 | bytes. |
| 1130 | |
Christian Heimes | d048637 | 2016-09-10 23:23:33 +0200 | [diff] [blame] | 1131 | .. deprecated:: 3.6 |
| 1132 | Use :meth:`~SSLSocket.recv` instead of :meth:`~SSLSocket.read`. |
| 1133 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1134 | .. method:: SSLSocket.write(buf) |
| 1135 | |
| 1136 | Write *buf* to the SSL socket and return the number of bytes written. The |
| 1137 | *buf* argument must be an object supporting the buffer interface. |
| 1138 | |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1139 | Raise :exc:`SSLWantReadError` or :exc:`SSLWantWriteError` if the socket is |
Victor Stinner | cfb2a0a | 2014-10-10 12:45:10 +0200 | [diff] [blame] | 1140 | :ref:`non-blocking <ssl-nonblocking>` and the write would block. |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1141 | |
| 1142 | As at any time a re-negotiation is possible, a call to :meth:`write` can |
| 1143 | also cause read operations. |
| 1144 | |
Victor Stinner | 1469070 | 2015-04-06 22:46:13 +0200 | [diff] [blame] | 1145 | .. versionchanged:: 3.5 |
| 1146 | The socket timeout is no more reset each time bytes are received or sent. |
| 1147 | The socket timeout is now to maximum total duration to write *buf*. |
| 1148 | |
Christian Heimes | d048637 | 2016-09-10 23:23:33 +0200 | [diff] [blame] | 1149 | .. deprecated:: 3.6 |
| 1150 | Use :meth:`~SSLSocket.send` instead of :meth:`~SSLSocket.write`. |
| 1151 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1152 | .. note:: |
| 1153 | |
| 1154 | The :meth:`~SSLSocket.read` and :meth:`~SSLSocket.write` methods are the |
| 1155 | low-level methods that read and write unencrypted, application-level data |
Martin Panter | 1f1177d | 2015-10-31 11:48:53 +0000 | [diff] [blame] | 1156 | and decrypt/encrypt it to encrypted, wire-level data. These methods |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1157 | require an active SSL connection, i.e. the handshake was completed and |
| 1158 | :meth:`SSLSocket.unwrap` was not called. |
| 1159 | |
| 1160 | Normally you should use the socket API methods like |
| 1161 | :meth:`~socket.socket.recv` and :meth:`~socket.socket.send` instead of these |
| 1162 | methods. |
| 1163 | |
Bill Janssen | 48dc27c | 2007-12-05 03:38:10 +0000 | [diff] [blame] | 1164 | .. method:: SSLSocket.do_handshake() |
| 1165 | |
Antoine Pitrou | b3593ca | 2011-07-11 01:39:19 +0200 | [diff] [blame] | 1166 | Perform the SSL setup handshake. |
Bill Janssen | 48dc27c | 2007-12-05 03:38:10 +0000 | [diff] [blame] | 1167 | |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1168 | .. versionchanged:: 3.4 |
Zachary Ware | 88a1977 | 2014-07-25 13:30:50 -0500 | [diff] [blame] | 1169 | The handshake method also performs :func:`match_hostname` when the |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1170 | :attr:`~SSLContext.check_hostname` attribute of the socket's |
| 1171 | :attr:`~SSLSocket.context` is true. |
| 1172 | |
Victor Stinner | 1469070 | 2015-04-06 22:46:13 +0200 | [diff] [blame] | 1173 | .. versionchanged:: 3.5 |
| 1174 | The socket timeout is no more reset each time bytes are received or sent. |
| 1175 | The socket timeout is now to maximum total duration of the handshake. |
| 1176 | |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 1177 | .. versionchanged:: 3.7 |
| 1178 | Hostname or IP address is matched by OpenSSL during handshake. The |
| 1179 | function :func:`match_hostname` is no longer used. In case OpenSSL |
| 1180 | refuses a hostname or IP address, the handshake is aborted early and |
| 1181 | a TLS alert message is send to the peer. |
| 1182 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1183 | .. method:: SSLSocket.getpeercert(binary_form=False) |
| 1184 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1185 | If there is no certificate for the peer on the other end of the connection, |
Antoine Pitrou | 20b8555 | 2013-09-29 19:50:53 +0200 | [diff] [blame] | 1186 | return ``None``. If the SSL handshake hasn't been done yet, raise |
| 1187 | :exc:`ValueError`. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1188 | |
Antoine Pitrou | d34941a | 2013-04-16 20:27:17 +0200 | [diff] [blame] | 1189 | If the ``binary_form`` parameter is :const:`False`, and a certificate was |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1190 | received from the peer, this method returns a :class:`dict` instance. If the |
| 1191 | certificate was not validated, the dict is empty. If the certificate was |
Antoine Pitrou | b7c6c81 | 2012-08-16 22:14:43 +0200 | [diff] [blame] | 1192 | validated, it returns a dict with several keys, amongst them ``subject`` |
| 1193 | (the principal for which the certificate was issued) and ``issuer`` |
| 1194 | (the principal issuing the certificate). If a certificate contains an |
| 1195 | instance of the *Subject Alternative Name* extension (see :rfc:`3280`), |
| 1196 | there will also be a ``subjectAltName`` key in the dictionary. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1197 | |
Antoine Pitrou | b7c6c81 | 2012-08-16 22:14:43 +0200 | [diff] [blame] | 1198 | The ``subject`` and ``issuer`` fields are tuples containing the sequence |
| 1199 | of relative distinguished names (RDNs) given in the certificate's data |
| 1200 | structure for the respective fields, and each RDN is a sequence of |
| 1201 | name-value pairs. Here is a real-world example:: |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1202 | |
Antoine Pitrou | b7c6c81 | 2012-08-16 22:14:43 +0200 | [diff] [blame] | 1203 | {'issuer': ((('countryName', 'IL'),), |
| 1204 | (('organizationName', 'StartCom Ltd.'),), |
| 1205 | (('organizationalUnitName', |
| 1206 | 'Secure Digital Certificate Signing'),), |
| 1207 | (('commonName', |
| 1208 | 'StartCom Class 2 Primary Intermediate Server CA'),)), |
| 1209 | 'notAfter': 'Nov 22 08:15:19 2013 GMT', |
| 1210 | 'notBefore': 'Nov 21 03:09:52 2011 GMT', |
| 1211 | 'serialNumber': '95F0', |
| 1212 | 'subject': ((('description', '571208-SLe257oHY9fVQ07Z'),), |
| 1213 | (('countryName', 'US'),), |
| 1214 | (('stateOrProvinceName', 'California'),), |
| 1215 | (('localityName', 'San Francisco'),), |
| 1216 | (('organizationName', 'Electronic Frontier Foundation, Inc.'),), |
| 1217 | (('commonName', '*.eff.org'),), |
| 1218 | (('emailAddress', 'hostmaster@eff.org'),)), |
| 1219 | 'subjectAltName': (('DNS', '*.eff.org'), ('DNS', 'eff.org')), |
| 1220 | 'version': 3} |
| 1221 | |
| 1222 | .. note:: |
Larry Hastings | 3732ed2 | 2014-03-15 21:13:56 -0700 | [diff] [blame] | 1223 | |
Antoine Pitrou | b7c6c81 | 2012-08-16 22:14:43 +0200 | [diff] [blame] | 1224 | To validate a certificate for a particular service, you can use the |
| 1225 | :func:`match_hostname` function. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1226 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1227 | If the ``binary_form`` parameter is :const:`True`, and a certificate was |
| 1228 | provided, this method returns the DER-encoded form of the entire certificate |
| 1229 | as a sequence of bytes, or :const:`None` if the peer did not provide a |
Antoine Pitrou | d34941a | 2013-04-16 20:27:17 +0200 | [diff] [blame] | 1230 | certificate. Whether the peer provides a certificate depends on the SSL |
| 1231 | socket's role: |
| 1232 | |
| 1233 | * for a client SSL socket, the server will always provide a certificate, |
| 1234 | regardless of whether validation was required; |
| 1235 | |
| 1236 | * for a server SSL socket, the client will only provide a certificate |
| 1237 | when requested by the server; therefore :meth:`getpeercert` will return |
| 1238 | :const:`None` if you used :const:`CERT_NONE` (rather than |
| 1239 | :const:`CERT_OPTIONAL` or :const:`CERT_REQUIRED`). |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1240 | |
Antoine Pitrou | fb04691 | 2010-11-09 20:21:19 +0000 | [diff] [blame] | 1241 | .. versionchanged:: 3.2 |
| 1242 | The returned dictionary includes additional items such as ``issuer`` |
| 1243 | and ``notBefore``. |
| 1244 | |
Antoine Pitrou | 20b8555 | 2013-09-29 19:50:53 +0200 | [diff] [blame] | 1245 | .. versionchanged:: 3.4 |
| 1246 | :exc:`ValueError` is raised when the handshake isn't done. |
Christian Heimes | bd3a7f9 | 2013-11-21 03:40:15 +0100 | [diff] [blame] | 1247 | The returned dictionary includes additional X509v3 extension items |
Larry Hastings | 3732ed2 | 2014-03-15 21:13:56 -0700 | [diff] [blame] | 1248 | such as ``crlDistributionPoints``, ``caIssuers`` and ``OCSP`` URIs. |
Christian Heimes | bd3a7f9 | 2013-11-21 03:40:15 +0100 | [diff] [blame] | 1249 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1250 | .. method:: SSLSocket.cipher() |
| 1251 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1252 | Returns a three-value tuple containing the name of the cipher being used, the |
| 1253 | version of the SSL protocol that defines its use, and the number of secret |
| 1254 | bits being used. If no connection has been established, returns ``None``. |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1255 | |
Benjamin Peterson | 4cb1781 | 2015-01-07 11:14:26 -0600 | [diff] [blame] | 1256 | .. method:: SSLSocket.shared_ciphers() |
| 1257 | |
| 1258 | Return the list of ciphers shared by the client during the handshake. Each |
| 1259 | entry of the returned list is a three-value tuple containing the name of the |
| 1260 | cipher, the version of the SSL protocol that defines its use, and the number |
| 1261 | of secret bits the cipher uses. :meth:`~SSLSocket.shared_ciphers` returns |
| 1262 | ``None`` if no connection has been established or the socket is a client |
| 1263 | socket. |
| 1264 | |
| 1265 | .. versionadded:: 3.5 |
| 1266 | |
Antoine Pitrou | 8abdb8a | 2011-12-20 10:13:40 +0100 | [diff] [blame] | 1267 | .. method:: SSLSocket.compression() |
| 1268 | |
| 1269 | Return the compression algorithm being used as a string, or ``None`` |
| 1270 | if the connection isn't compressed. |
| 1271 | |
| 1272 | If the higher-level protocol supports its own compression mechanism, |
| 1273 | you can use :data:`OP_NO_COMPRESSION` to disable SSL-level compression. |
| 1274 | |
| 1275 | .. versionadded:: 3.3 |
| 1276 | |
Antoine Pitrou | d649480 | 2011-07-21 01:11:30 +0200 | [diff] [blame] | 1277 | .. method:: SSLSocket.get_channel_binding(cb_type="tls-unique") |
| 1278 | |
| 1279 | Get channel binding data for current connection, as a bytes object. Returns |
| 1280 | ``None`` if not connected or the handshake has not been completed. |
| 1281 | |
| 1282 | The *cb_type* parameter allow selection of the desired channel binding |
| 1283 | type. Valid channel binding types are listed in the |
| 1284 | :data:`CHANNEL_BINDING_TYPES` list. Currently only the 'tls-unique' channel |
| 1285 | binding, defined by :rfc:`5929`, is supported. :exc:`ValueError` will be |
| 1286 | raised if an unsupported channel binding type is requested. |
| 1287 | |
| 1288 | .. versionadded:: 3.3 |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1289 | |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1290 | .. method:: SSLSocket.selected_alpn_protocol() |
| 1291 | |
| 1292 | Return the protocol that was selected during the TLS handshake. If |
| 1293 | :meth:`SSLContext.set_alpn_protocols` was not called, if the other party does |
Benjamin Peterson | 8861502 | 2015-01-23 17:30:26 -0500 | [diff] [blame] | 1294 | not support ALPN, if this socket does not support any of the client's |
| 1295 | proposed protocols, or if the handshake has not happened yet, ``None`` is |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1296 | returned. |
| 1297 | |
| 1298 | .. versionadded:: 3.5 |
| 1299 | |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 1300 | .. method:: SSLSocket.selected_npn_protocol() |
| 1301 | |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1302 | Return the higher-level protocol that was selected during the TLS/SSL |
Antoine Pitrou | 47e4042 | 2014-09-04 21:00:10 +0200 | [diff] [blame] | 1303 | handshake. If :meth:`SSLContext.set_npn_protocols` was not called, or |
| 1304 | if the other party does not support NPN, or if the handshake has not yet |
| 1305 | happened, this will return ``None``. |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 1306 | |
| 1307 | .. versionadded:: 3.3 |
| 1308 | |
Benjamin Peterson | 4aeec04 | 2008-08-19 21:42:13 +0000 | [diff] [blame] | 1309 | .. method:: SSLSocket.unwrap() |
| 1310 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1311 | Performs the SSL shutdown handshake, which removes the TLS layer from the |
| 1312 | underlying socket, and returns the underlying socket object. This can be |
| 1313 | used to go from encrypted operation over a connection to unencrypted. The |
| 1314 | returned socket should always be used for further communication with the |
| 1315 | other side of the connection, rather than the original socket. |
Benjamin Peterson | 4aeec04 | 2008-08-19 21:42:13 +0000 | [diff] [blame] | 1316 | |
Antoine Pitrou | 47e4042 | 2014-09-04 21:00:10 +0200 | [diff] [blame] | 1317 | .. method:: SSLSocket.version() |
| 1318 | |
| 1319 | Return the actual SSL protocol version negotiated by the connection |
| 1320 | as a string, or ``None`` is no secure connection is established. |
| 1321 | As of this writing, possible return values include ``"SSLv2"``, |
| 1322 | ``"SSLv3"``, ``"TLSv1"``, ``"TLSv1.1"`` and ``"TLSv1.2"``. |
| 1323 | Recent OpenSSL versions may define more return values. |
| 1324 | |
| 1325 | .. versionadded:: 3.5 |
| 1326 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1327 | .. method:: SSLSocket.pending() |
| 1328 | |
| 1329 | Returns the number of already decrypted bytes available for read, pending on |
| 1330 | the connection. |
| 1331 | |
Antoine Pitrou | ec883db | 2010-05-24 21:20:20 +0000 | [diff] [blame] | 1332 | .. attribute:: SSLSocket.context |
| 1333 | |
| 1334 | The :class:`SSLContext` object this SSL socket is tied to. If the SSL |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 1335 | socket was created using the deprecated :func:`wrap_socket` function |
Antoine Pitrou | ec883db | 2010-05-24 21:20:20 +0000 | [diff] [blame] | 1336 | (rather than :meth:`SSLContext.wrap_socket`), this is a custom context |
| 1337 | object created for this SSL socket. |
| 1338 | |
| 1339 | .. versionadded:: 3.2 |
| 1340 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1341 | .. attribute:: SSLSocket.server_side |
| 1342 | |
| 1343 | A boolean which is ``True`` for server-side sockets and ``False`` for |
| 1344 | client-side sockets. |
| 1345 | |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1346 | .. versionadded:: 3.2 |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1347 | |
| 1348 | .. attribute:: SSLSocket.server_hostname |
| 1349 | |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1350 | Hostname of the server: :class:`str` type, or ``None`` for server-side |
| 1351 | socket or if the hostname was not specified in the constructor. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1352 | |
Victor Stinner | 41f92c2 | 2014-10-10 12:05:56 +0200 | [diff] [blame] | 1353 | .. versionadded:: 3.2 |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 1354 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1355 | .. versionchanged:: 3.7 |
| 1356 | The attribute is now always ASCII text. When ``server_hostname`` is |
| 1357 | an internationalized domain name (IDN), this attribute now stores the |
| 1358 | A-label form (``"xn--pythn-mua.org"``), rather than the U-label form |
| 1359 | (``"pythön.org"``). |
| 1360 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1361 | .. attribute:: SSLSocket.session |
| 1362 | |
| 1363 | The :class:`SSLSession` for this SSL connection. The session is available |
| 1364 | for client and server side sockets after the TLS handshake has been |
| 1365 | performed. For client sockets the session can be set before |
| 1366 | :meth:`~SSLSocket.do_handshake` has been called to reuse a session. |
| 1367 | |
| 1368 | .. versionadded:: 3.6 |
| 1369 | |
| 1370 | .. attribute:: SSLSocket.session_reused |
| 1371 | |
| 1372 | .. versionadded:: 3.6 |
| 1373 | |
Antoine Pitrou | ec883db | 2010-05-24 21:20:20 +0000 | [diff] [blame] | 1374 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1375 | SSL Contexts |
| 1376 | ------------ |
| 1377 | |
Antoine Pitrou | cafaad4 | 2010-05-24 15:58:43 +0000 | [diff] [blame] | 1378 | .. versionadded:: 3.2 |
| 1379 | |
Antoine Pitrou | b0182c8 | 2010-10-12 20:09:02 +0000 | [diff] [blame] | 1380 | An SSL context holds various data longer-lived than single SSL connections, |
| 1381 | such as SSL configuration options, certificate(s) and private key(s). |
| 1382 | It also manages a cache of SSL sessions for server-side sockets, in order |
| 1383 | to speed up repeated connections from the same clients. |
| 1384 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 1385 | .. class:: SSLContext(protocol=PROTOCOL_TLS) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1386 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 1387 | Create a new SSL context. You may pass *protocol* which must be one |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 1388 | of the ``PROTOCOL_*`` constants defined in this module. The parameter |
| 1389 | specifies which version of the SSL protocol to use. Typically, the |
| 1390 | server chooses a particular protocol version, and the client must adapt |
| 1391 | to the server's choice. Most of the versions are not interoperable |
| 1392 | with the other versions. If not specified, the default is |
| 1393 | :data:`PROTOCOL_TLS`; it provides the most compatibility with other |
| 1394 | versions. |
| 1395 | |
| 1396 | Here's a table showing which versions in a client (down the side) can connect |
| 1397 | to which versions in a server (along the top): |
| 1398 | |
| 1399 | .. table:: |
| 1400 | |
| 1401 | ======================== ============ ============ ============= ========= =========== =========== |
| 1402 | *client* / **server** **SSLv2** **SSLv3** **TLS** [3]_ **TLSv1** **TLSv1.1** **TLSv1.2** |
| 1403 | ------------------------ ------------ ------------ ------------- --------- ----------- ----------- |
| 1404 | *SSLv2* yes no no [1]_ no no no |
| 1405 | *SSLv3* no yes no [2]_ no no no |
| 1406 | *TLS* (*SSLv23*) [3]_ no [1]_ no [2]_ yes yes yes yes |
| 1407 | *TLSv1* no no yes yes no no |
| 1408 | *TLSv1.1* no no yes no yes no |
| 1409 | *TLSv1.2* no no yes no no yes |
| 1410 | ======================== ============ ============ ============= ========= =========== =========== |
| 1411 | |
| 1412 | .. rubric:: Footnotes |
| 1413 | .. [1] :class:`SSLContext` disables SSLv2 with :data:`OP_NO_SSLv2` by default. |
| 1414 | .. [2] :class:`SSLContext` disables SSLv3 with :data:`OP_NO_SSLv3` by default. |
| 1415 | .. [3] TLS 1.3 protocol will be available with :data:`PROTOCOL_TLS` in |
| 1416 | OpenSSL >= 1.1.1. There is no dedicated PROTOCOL constant for just |
| 1417 | TLS 1.3. |
Antoine Pitrou | 5bef410 | 2013-11-23 16:16:29 +0100 | [diff] [blame] | 1418 | |
| 1419 | .. seealso:: |
| 1420 | :func:`create_default_context` lets the :mod:`ssl` module choose |
| 1421 | security settings for a given purpose. |
Antoine Pitrou | b0182c8 | 2010-10-12 20:09:02 +0000 | [diff] [blame] | 1422 | |
Christian Heimes | 01113fa | 2016-09-05 23:23:24 +0200 | [diff] [blame] | 1423 | .. versionchanged:: 3.6 |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 1424 | |
Christian Heimes | 358cfd4 | 2016-09-10 22:43:48 +0200 | [diff] [blame] | 1425 | The context is created with secure default values. The options |
| 1426 | :data:`OP_NO_COMPRESSION`, :data:`OP_CIPHER_SERVER_PREFERENCE`, |
| 1427 | :data:`OP_SINGLE_DH_USE`, :data:`OP_SINGLE_ECDH_USE`, |
| 1428 | :data:`OP_NO_SSLv2` (except for :data:`PROTOCOL_SSLv2`), |
| 1429 | and :data:`OP_NO_SSLv3` (except for :data:`PROTOCOL_SSLv3`) are |
| 1430 | set by default. The initial cipher suite list contains only ``HIGH`` |
| 1431 | ciphers, no ``NULL`` ciphers and no ``MD5`` ciphers (except for |
| 1432 | :data:`PROTOCOL_SSLv2`). |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 1433 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1434 | |
| 1435 | :class:`SSLContext` objects have the following methods and attributes: |
| 1436 | |
Christian Heimes | 9a5395a | 2013-06-17 15:44:12 +0200 | [diff] [blame] | 1437 | .. method:: SSLContext.cert_store_stats() |
| 1438 | |
| 1439 | Get statistics about quantities of loaded X.509 certificates, count of |
| 1440 | X.509 certificates flagged as CA certificates and certificate revocation |
| 1441 | lists as dictionary. |
| 1442 | |
| 1443 | Example for a context with one CA cert and one other cert:: |
| 1444 | |
| 1445 | >>> context.cert_store_stats() |
| 1446 | {'crl': 0, 'x509_ca': 1, 'x509': 2} |
| 1447 | |
| 1448 | .. versionadded:: 3.4 |
| 1449 | |
Christian Heimes | efff706 | 2013-11-21 03:35:02 +0100 | [diff] [blame] | 1450 | |
Antoine Pitrou | 4fd1e6a | 2011-08-25 14:39:44 +0200 | [diff] [blame] | 1451 | .. method:: SSLContext.load_cert_chain(certfile, keyfile=None, password=None) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1452 | |
| 1453 | Load a private key and the corresponding certificate. The *certfile* |
| 1454 | string must be the path to a single file in PEM format containing the |
| 1455 | certificate as well as any number of CA certificates needed to establish |
| 1456 | the certificate's authenticity. The *keyfile* string, if present, must |
| 1457 | point to a file containing the private key in. Otherwise the private |
| 1458 | key will be taken from *certfile* as well. See the discussion of |
| 1459 | :ref:`ssl-certificates` for more information on how the certificate |
| 1460 | is stored in the *certfile*. |
| 1461 | |
Antoine Pitrou | 4fd1e6a | 2011-08-25 14:39:44 +0200 | [diff] [blame] | 1462 | The *password* argument may be a function to call to get the password for |
| 1463 | decrypting the private key. It will only be called if the private key is |
| 1464 | encrypted and a password is necessary. It will be called with no arguments, |
| 1465 | and it should return a string, bytes, or bytearray. If the return value is |
| 1466 | a string it will be encoded as UTF-8 before using it to decrypt the key. |
| 1467 | Alternatively a string, bytes, or bytearray value may be supplied directly |
| 1468 | as the *password* argument. It will be ignored if the private key is not |
| 1469 | encrypted and no password is needed. |
| 1470 | |
| 1471 | If the *password* argument is not specified and a password is required, |
| 1472 | OpenSSL's built-in password prompting mechanism will be used to |
| 1473 | interactively prompt the user for a password. |
| 1474 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1475 | An :class:`SSLError` is raised if the private key doesn't |
| 1476 | match with the certificate. |
| 1477 | |
Antoine Pitrou | 4fd1e6a | 2011-08-25 14:39:44 +0200 | [diff] [blame] | 1478 | .. versionchanged:: 3.3 |
| 1479 | New optional argument *password*. |
| 1480 | |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1481 | .. method:: SSLContext.load_default_certs(purpose=Purpose.SERVER_AUTH) |
| 1482 | |
| 1483 | Load a set of default "certification authority" (CA) certificates from |
| 1484 | default locations. On Windows it loads CA certs from the ``CA`` and |
| 1485 | ``ROOT`` system stores. On other systems it calls |
| 1486 | :meth:`SSLContext.set_default_verify_paths`. In the future the method may |
| 1487 | load CA certificates from other locations, too. |
| 1488 | |
| 1489 | The *purpose* flag specifies what kind of CA certificates are loaded. The |
| 1490 | default settings :data:`Purpose.SERVER_AUTH` loads certificates, that are |
| 1491 | flagged and trusted for TLS web server authentication (client side |
Christian Heimes | 6b2ff98 | 2013-11-23 14:42:01 +0100 | [diff] [blame] | 1492 | sockets). :data:`Purpose.CLIENT_AUTH` loads CA certificates for client |
Christian Heimes | 72d2850 | 2013-11-23 13:56:58 +0100 | [diff] [blame] | 1493 | certificate verification on the server side. |
| 1494 | |
| 1495 | .. versionadded:: 3.4 |
| 1496 | |
Christian Heimes | efff706 | 2013-11-21 03:35:02 +0100 | [diff] [blame] | 1497 | .. method:: SSLContext.load_verify_locations(cafile=None, capath=None, cadata=None) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1498 | |
| 1499 | Load a set of "certification authority" (CA) certificates used to validate |
| 1500 | other peers' certificates when :data:`verify_mode` is other than |
| 1501 | :data:`CERT_NONE`. At least one of *cafile* or *capath* must be specified. |
| 1502 | |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 1503 | This method can also load certification revocation lists (CRLs) in PEM or |
Donald Stufft | 8b852f1 | 2014-05-20 12:58:38 -0400 | [diff] [blame] | 1504 | DER format. In order to make use of CRLs, :attr:`SSLContext.verify_flags` |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 1505 | must be configured properly. |
| 1506 | |
Christian Heimes | 3e738f9 | 2013-06-09 18:07:16 +0200 | [diff] [blame] | 1507 | The *cafile* string, if present, is the path to a file of concatenated |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1508 | CA certificates in PEM format. See the discussion of |
| 1509 | :ref:`ssl-certificates` for more information about how to arrange the |
| 1510 | certificates in this file. |
| 1511 | |
| 1512 | The *capath* string, if present, is |
| 1513 | the path to a directory containing several CA certificates in PEM format, |
| 1514 | following an `OpenSSL specific layout |
Sanyam Khurana | 338cd83 | 2018-01-20 05:55:37 +0530 | [diff] [blame] | 1515 | <https://www.openssl.org/docs/manmaster/man3/SSL_CTX_load_verify_locations.html>`_. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1516 | |
Christian Heimes | efff706 | 2013-11-21 03:35:02 +0100 | [diff] [blame] | 1517 | The *cadata* object, if present, is either an ASCII string of one or more |
Serhiy Storchaka | b757c83 | 2014-12-05 22:25:22 +0200 | [diff] [blame] | 1518 | PEM-encoded certificates or a :term:`bytes-like object` of DER-encoded |
Christian Heimes | efff706 | 2013-11-21 03:35:02 +0100 | [diff] [blame] | 1519 | certificates. Like with *capath* extra lines around PEM-encoded |
| 1520 | certificates are ignored but at least one certificate must be present. |
| 1521 | |
| 1522 | .. versionchanged:: 3.4 |
| 1523 | New optional argument *cadata* |
| 1524 | |
Christian Heimes | 9a5395a | 2013-06-17 15:44:12 +0200 | [diff] [blame] | 1525 | .. method:: SSLContext.get_ca_certs(binary_form=False) |
| 1526 | |
| 1527 | Get a list of loaded "certification authority" (CA) certificates. If the |
| 1528 | ``binary_form`` parameter is :const:`False` each list |
| 1529 | entry is a dict like the output of :meth:`SSLSocket.getpeercert`. Otherwise |
| 1530 | the method returns a list of DER-encoded certificates. The returned list |
| 1531 | does not contain certificates from *capath* unless a certificate was |
| 1532 | requested and loaded by a SSL connection. |
| 1533 | |
Antoine Pitrou | 97aa953 | 2015-04-13 21:06:15 +0200 | [diff] [blame] | 1534 | .. note:: |
| 1535 | Certificates in a capath directory aren't loaded unless they have |
| 1536 | been used at least once. |
| 1537 | |
Larry Hastings | d36fc43 | 2013-08-03 02:49:53 -0700 | [diff] [blame] | 1538 | .. versionadded:: 3.4 |
Christian Heimes | 9a5395a | 2013-06-17 15:44:12 +0200 | [diff] [blame] | 1539 | |
Christian Heimes | 25bfcd5 | 2016-09-06 00:04:45 +0200 | [diff] [blame] | 1540 | .. method:: SSLContext.get_ciphers() |
| 1541 | |
| 1542 | Get a list of enabled ciphers. The list is in order of cipher priority. |
| 1543 | See :meth:`SSLContext.set_ciphers`. |
| 1544 | |
| 1545 | Example:: |
| 1546 | |
| 1547 | >>> ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23) |
| 1548 | >>> ctx.set_ciphers('ECDHE+AESGCM:!ECDSA') |
| 1549 | >>> ctx.get_ciphers() # OpenSSL 1.0.x |
| 1550 | [{'alg_bits': 256, |
| 1551 | 'description': 'ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA ' |
| 1552 | 'Enc=AESGCM(256) Mac=AEAD', |
| 1553 | 'id': 50380848, |
| 1554 | 'name': 'ECDHE-RSA-AES256-GCM-SHA384', |
| 1555 | 'protocol': 'TLSv1/SSLv3', |
| 1556 | 'strength_bits': 256}, |
| 1557 | {'alg_bits': 128, |
| 1558 | 'description': 'ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA ' |
| 1559 | 'Enc=AESGCM(128) Mac=AEAD', |
| 1560 | 'id': 50380847, |
| 1561 | 'name': 'ECDHE-RSA-AES128-GCM-SHA256', |
| 1562 | 'protocol': 'TLSv1/SSLv3', |
| 1563 | 'strength_bits': 128}] |
| 1564 | |
| 1565 | On OpenSSL 1.1 and newer the cipher dict contains additional fields:: |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 1566 | |
Christian Heimes | 25bfcd5 | 2016-09-06 00:04:45 +0200 | [diff] [blame] | 1567 | >>> ctx.get_ciphers() # OpenSSL 1.1+ |
| 1568 | [{'aead': True, |
| 1569 | 'alg_bits': 256, |
| 1570 | 'auth': 'auth-rsa', |
| 1571 | 'description': 'ECDHE-RSA-AES256-GCM-SHA384 TLSv1.2 Kx=ECDH Au=RSA ' |
| 1572 | 'Enc=AESGCM(256) Mac=AEAD', |
| 1573 | 'digest': None, |
| 1574 | 'id': 50380848, |
| 1575 | 'kea': 'kx-ecdhe', |
| 1576 | 'name': 'ECDHE-RSA-AES256-GCM-SHA384', |
| 1577 | 'protocol': 'TLSv1.2', |
| 1578 | 'strength_bits': 256, |
| 1579 | 'symmetric': 'aes-256-gcm'}, |
| 1580 | {'aead': True, |
| 1581 | 'alg_bits': 128, |
| 1582 | 'auth': 'auth-rsa', |
| 1583 | 'description': 'ECDHE-RSA-AES128-GCM-SHA256 TLSv1.2 Kx=ECDH Au=RSA ' |
| 1584 | 'Enc=AESGCM(128) Mac=AEAD', |
| 1585 | 'digest': None, |
| 1586 | 'id': 50380847, |
| 1587 | 'kea': 'kx-ecdhe', |
| 1588 | 'name': 'ECDHE-RSA-AES128-GCM-SHA256', |
| 1589 | 'protocol': 'TLSv1.2', |
| 1590 | 'strength_bits': 128, |
| 1591 | 'symmetric': 'aes-128-gcm'}] |
| 1592 | |
| 1593 | Availability: OpenSSL 1.0.2+ |
| 1594 | |
| 1595 | .. versionadded:: 3.6 |
| 1596 | |
Antoine Pitrou | 664c2d1 | 2010-11-17 20:29:42 +0000 | [diff] [blame] | 1597 | .. method:: SSLContext.set_default_verify_paths() |
| 1598 | |
| 1599 | Load a set of default "certification authority" (CA) certificates from |
| 1600 | a filesystem path defined when building the OpenSSL library. Unfortunately, |
| 1601 | there's no easy way to know whether this method succeeds: no error is |
| 1602 | returned if no certificates are to be found. When the OpenSSL library is |
| 1603 | provided as part of the operating system, though, it is likely to be |
| 1604 | configured properly. |
| 1605 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1606 | .. method:: SSLContext.set_ciphers(ciphers) |
| 1607 | |
| 1608 | Set the available ciphers for sockets created with this context. |
| 1609 | It should be a string in the `OpenSSL cipher list format |
Marcin Niemira | 9c5ba09 | 2018-07-08 00:24:20 +0200 | [diff] [blame] | 1610 | <https://www.openssl.org/docs/manmaster/man1/ciphers.html>`_. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1611 | If no cipher can be selected (because compile-time options or other |
| 1612 | configuration forbids use of all the specified ciphers), an |
| 1613 | :class:`SSLError` will be raised. |
| 1614 | |
| 1615 | .. note:: |
| 1616 | when connected, the :meth:`SSLSocket.cipher` method of SSL sockets will |
| 1617 | give the currently selected cipher. |
| 1618 | |
Christian Heimes | e8eb6cb | 2018-05-22 22:50:12 +0200 | [diff] [blame] | 1619 | OpenSSL 1.1.1 has TLS 1.3 cipher suites enabled by default. The suites |
| 1620 | cannot be disabled with :meth:`~SSLContext.set_ciphers`. |
| 1621 | |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1622 | .. method:: SSLContext.set_alpn_protocols(protocols) |
| 1623 | |
| 1624 | Specify which protocols the socket should advertise during the SSL/TLS |
| 1625 | handshake. It should be a list of ASCII strings, like ``['http/1.1', |
| 1626 | 'spdy/2']``, ordered by preference. The selection of a protocol will happen |
| 1627 | during the handshake, and will play out according to :rfc:`7301`. After a |
| 1628 | successful handshake, the :meth:`SSLSocket.selected_alpn_protocol` method will |
| 1629 | return the agreed-upon protocol. |
| 1630 | |
| 1631 | This method will raise :exc:`NotImplementedError` if :data:`HAS_ALPN` is |
| 1632 | False. |
| 1633 | |
Christian Heimes | 7b40cb7 | 2017-08-15 10:33:43 +0200 | [diff] [blame] | 1634 | OpenSSL 1.1.0 to 1.1.0e will abort the handshake and raise :exc:`SSLError` |
| 1635 | when both sides support ALPN but cannot agree on a protocol. 1.1.0f+ |
| 1636 | behaves like 1.0.2, :meth:`SSLSocket.selected_alpn_protocol` returns None. |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 1637 | |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1638 | .. versionadded:: 3.5 |
| 1639 | |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 1640 | .. method:: SSLContext.set_npn_protocols(protocols) |
| 1641 | |
R David Murray | c7f7579 | 2013-06-26 15:11:12 -0400 | [diff] [blame] | 1642 | Specify which protocols the socket should advertise during the SSL/TLS |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 1643 | handshake. It should be a list of strings, like ``['http/1.1', 'spdy/2']``, |
| 1644 | ordered by preference. The selection of a protocol will happen during the |
Sanyam Khurana | 338cd83 | 2018-01-20 05:55:37 +0530 | [diff] [blame] | 1645 | handshake, and will play out according to the `Application Layer Protocol Negotiation |
| 1646 | <https://en.wikipedia.org/wiki/Application-Layer_Protocol_Negotiation>`_. After a |
Antoine Pitrou | d5d17eb | 2012-03-22 00:23:03 +0100 | [diff] [blame] | 1647 | successful handshake, the :meth:`SSLSocket.selected_npn_protocol` method will |
| 1648 | return the agreed-upon protocol. |
| 1649 | |
| 1650 | This method will raise :exc:`NotImplementedError` if :data:`HAS_NPN` is |
| 1651 | False. |
| 1652 | |
| 1653 | .. versionadded:: 3.3 |
| 1654 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1655 | .. attribute:: SSLContext.sni_callback |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1656 | |
| 1657 | Register a callback function that will be called after the TLS Client Hello |
| 1658 | handshake message has been received by the SSL/TLS server when the TLS client |
| 1659 | specifies a server name indication. The server name indication mechanism |
| 1660 | is specified in :rfc:`6066` section 3 - Server Name Indication. |
| 1661 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1662 | Only one callback can be set per ``SSLContext``. If *sni_callback* |
| 1663 | is set to ``None`` then the callback is disabled. Calling this function a |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1664 | subsequent time will disable the previously registered callback. |
| 1665 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1666 | The callback function will be called with three |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1667 | arguments; the first being the :class:`ssl.SSLSocket`, the second is a string |
| 1668 | that represents the server name that the client is intending to communicate |
Antoine Pitrou | 50b24d0 | 2013-04-11 20:48:42 +0200 | [diff] [blame] | 1669 | (or :const:`None` if the TLS Client Hello does not contain a server name) |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1670 | and the third argument is the original :class:`SSLContext`. The server name |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1671 | argument is text. For internationalized domain name, the server |
| 1672 | name is an IDN A-label (``"xn--pythn-mua.org"``). |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1673 | |
| 1674 | A typical use of this callback is to change the :class:`ssl.SSLSocket`'s |
| 1675 | :attr:`SSLSocket.context` attribute to a new object of type |
| 1676 | :class:`SSLContext` representing a certificate chain that matches the server |
| 1677 | name. |
| 1678 | |
| 1679 | Due to the early negotiation phase of the TLS connection, only limited |
| 1680 | methods and attributes are usable like |
Benjamin Peterson | cca2732 | 2015-01-23 16:35:37 -0500 | [diff] [blame] | 1681 | :meth:`SSLSocket.selected_alpn_protocol` and :attr:`SSLSocket.context`. |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1682 | :meth:`SSLSocket.getpeercert`, :meth:`SSLSocket.getpeercert`, |
| 1683 | :meth:`SSLSocket.cipher` and :meth:`SSLSocket.compress` methods require that |
| 1684 | the TLS connection has progressed beyond the TLS Client Hello and therefore |
| 1685 | will not contain return meaningful values nor can they be called safely. |
| 1686 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1687 | The *sni_callback* function must return ``None`` to allow the |
Terry Jan Reedy | 8e7586b | 2013-03-11 18:38:13 -0400 | [diff] [blame] | 1688 | TLS negotiation to continue. If a TLS failure is required, a constant |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1689 | :const:`ALERT_DESCRIPTION_* <ALERT_DESCRIPTION_INTERNAL_ERROR>` can be |
| 1690 | returned. Other return values will result in a TLS fatal error with |
| 1691 | :const:`ALERT_DESCRIPTION_INTERNAL_ERROR`. |
| 1692 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1693 | If an exception is raised from the *sni_callback* function the TLS |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1694 | connection will terminate with a fatal TLS alert message |
| 1695 | :const:`ALERT_DESCRIPTION_HANDSHAKE_FAILURE`. |
| 1696 | |
| 1697 | This method will raise :exc:`NotImplementedError` if the OpenSSL library |
| 1698 | had OPENSSL_NO_TLSEXT defined when it was built. |
| 1699 | |
Christian Heimes | 11a1493 | 2018-02-24 02:35:08 +0100 | [diff] [blame] | 1700 | .. versionadded:: 3.7 |
| 1701 | |
| 1702 | .. attribute:: SSLContext.set_servername_callback(server_name_callback) |
| 1703 | |
| 1704 | This is a legacy API retained for backwards compatibility. When possible, |
| 1705 | you should use :attr:`sni_callback` instead. The given *server_name_callback* |
| 1706 | is similar to *sni_callback*, except that when the server hostname is an |
| 1707 | IDN-encoded internationalized domain name, the *server_name_callback* |
| 1708 | receives a decoded U-label (``"pythön.org"``). |
| 1709 | |
| 1710 | If there is an decoding error on the server name, the TLS connection will |
| 1711 | terminate with an :const:`ALERT_DESCRIPTION_INTERNAL_ERROR` fatal TLS |
| 1712 | alert message to the client. |
| 1713 | |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 1714 | .. versionadded:: 3.4 |
| 1715 | |
Antoine Pitrou | 0e576f1 | 2011-12-22 10:03:38 +0100 | [diff] [blame] | 1716 | .. method:: SSLContext.load_dh_params(dhfile) |
| 1717 | |
Matt Eaton | 9cf8c42 | 2018-03-10 19:00:04 -0600 | [diff] [blame] | 1718 | Load the key generation parameters for Diffie-Hellman (DH) key exchange. |
Antoine Pitrou | 0e576f1 | 2011-12-22 10:03:38 +0100 | [diff] [blame] | 1719 | Using DH key exchange improves forward secrecy at the expense of |
| 1720 | computational resources (both on the server and on the client). |
| 1721 | The *dhfile* parameter should be the path to a file containing DH |
| 1722 | parameters in PEM format. |
| 1723 | |
| 1724 | This setting doesn't apply to client sockets. You can also use the |
| 1725 | :data:`OP_SINGLE_DH_USE` option to further improve security. |
| 1726 | |
| 1727 | .. versionadded:: 3.3 |
| 1728 | |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 1729 | .. method:: SSLContext.set_ecdh_curve(curve_name) |
| 1730 | |
Antoine Pitrou | 0e576f1 | 2011-12-22 10:03:38 +0100 | [diff] [blame] | 1731 | Set the curve name for Elliptic Curve-based Diffie-Hellman (ECDH) key |
| 1732 | exchange. ECDH is significantly faster than regular DH while arguably |
| 1733 | as secure. The *curve_name* parameter should be a string describing |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 1734 | a well-known elliptic curve, for example ``prime256v1`` for a widely |
| 1735 | supported curve. |
| 1736 | |
| 1737 | This setting doesn't apply to client sockets. You can also use the |
| 1738 | :data:`OP_SINGLE_ECDH_USE` option to further improve security. |
| 1739 | |
Serhiy Storchaka | 4adf01c | 2016-10-19 18:30:05 +0300 | [diff] [blame] | 1740 | This method is not available if :data:`HAS_ECDH` is ``False``. |
Antoine Pitrou | 501da61 | 2011-12-21 09:27:41 +0100 | [diff] [blame] | 1741 | |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 1742 | .. versionadded:: 3.3 |
| 1743 | |
| 1744 | .. seealso:: |
Sanyam Khurana | 1b4587a | 2017-12-06 22:09:33 +0530 | [diff] [blame] | 1745 | `SSL/TLS & Perfect Forward Secrecy <https://vincent.bernat.im/en/blog/2011-ssl-perfect-forward-secrecy>`_ |
Antoine Pitrou | 923df6f | 2011-12-19 17:16:51 +0100 | [diff] [blame] | 1746 | Vincent Bernat. |
| 1747 | |
Antoine Pitrou | d532321 | 2010-10-22 18:19:07 +0000 | [diff] [blame] | 1748 | .. method:: SSLContext.wrap_socket(sock, server_side=False, \ |
| 1749 | do_handshake_on_connect=True, suppress_ragged_eofs=True, \ |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1750 | server_hostname=None, session=None) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1751 | |
Christian Heimes | 4df60f1 | 2017-09-15 20:26:05 +0200 | [diff] [blame] | 1752 | Wrap an existing Python socket *sock* and return an instance of |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 1753 | :attr:`SSLContext.sslsocket_class` (default :class:`SSLSocket`). The |
| 1754 | returned SSL socket is tied to the context, its settings and certificates. |
| 1755 | *sock* must be a :data:`~socket.SOCK_STREAM` socket; other |
| 1756 | socket types are unsupported. |
Antoine Pitrou | 3e86ba4 | 2013-12-28 17:26:33 +0100 | [diff] [blame] | 1757 | |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 1758 | The parameter ``server_side`` is a boolean which identifies whether |
| 1759 | server-side or client-side behavior is desired from this socket. |
| 1760 | |
| 1761 | For client-side sockets, the context construction is lazy; if the |
| 1762 | underlying socket isn't connected yet, the context construction will be |
| 1763 | performed after :meth:`connect` is called on the socket. For |
| 1764 | server-side sockets, if the socket has no remote peer, it is assumed |
| 1765 | to be a listening socket, and the server-side SSL wrapping is |
| 1766 | automatically performed on client connections accepted via the |
| 1767 | :meth:`accept` method. The method may raise :exc:`SSLError`. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1768 | |
Antoine Pitrou | d532321 | 2010-10-22 18:19:07 +0000 | [diff] [blame] | 1769 | On client connections, the optional parameter *server_hostname* specifies |
| 1770 | the hostname of the service which we are connecting to. This allows a |
| 1771 | single server to host multiple SSL-based services with distinct certificates, |
Benjamin Peterson | 7243b57 | 2014-11-23 17:04:34 -0600 | [diff] [blame] | 1772 | quite similarly to HTTP virtual hosts. Specifying *server_hostname* will |
| 1773 | raise a :exc:`ValueError` if *server_side* is true. |
| 1774 | |
Christian Heimes | 90f05a5 | 2018-02-27 09:21:34 +0100 | [diff] [blame] | 1775 | The parameter ``do_handshake_on_connect`` specifies whether to do the SSL |
| 1776 | handshake automatically after doing a :meth:`socket.connect`, or whether the |
| 1777 | application program will call it explicitly, by invoking the |
| 1778 | :meth:`SSLSocket.do_handshake` method. Calling |
| 1779 | :meth:`SSLSocket.do_handshake` explicitly gives the program control over the |
| 1780 | blocking behavior of the socket I/O involved in the handshake. |
| 1781 | |
| 1782 | The parameter ``suppress_ragged_eofs`` specifies how the |
| 1783 | :meth:`SSLSocket.recv` method should signal unexpected EOF from the other end |
| 1784 | of the connection. If specified as :const:`True` (the default), it returns a |
| 1785 | normal EOF (an empty bytes object) in response to unexpected EOF errors |
| 1786 | raised from the underlying socket; if :const:`False`, it will raise the |
| 1787 | exceptions back to the caller. |
| 1788 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1789 | *session*, see :attr:`~SSLSocket.session`. |
| 1790 | |
Benjamin Peterson | 7243b57 | 2014-11-23 17:04:34 -0600 | [diff] [blame] | 1791 | .. versionchanged:: 3.5 |
| 1792 | Always allow a server_hostname to be passed, even if OpenSSL does not |
| 1793 | have SNI. |
Antoine Pitrou | d532321 | 2010-10-22 18:19:07 +0000 | [diff] [blame] | 1794 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1795 | .. versionchanged:: 3.6 |
| 1796 | *session* argument was added. |
| 1797 | |
Christian Heimes | 4df60f1 | 2017-09-15 20:26:05 +0200 | [diff] [blame] | 1798 | .. versionchanged:: 3.7 |
| 1799 | The method returns on instance of :attr:`SSLContext.sslsocket_class` |
| 1800 | instead of hard-coded :class:`SSLSocket`. |
| 1801 | |
| 1802 | .. attribute:: SSLContext.sslsocket_class |
| 1803 | |
| 1804 | The return type of :meth:`SSLContext.wrap_sockets`, defaults to |
| 1805 | :class:`SSLSocket`. The attribute can be overridden on instance of class |
| 1806 | in order to return a custom subclass of :class:`SSLSocket`. |
| 1807 | |
| 1808 | .. versionadded:: 3.7 |
| 1809 | |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 1810 | .. method:: SSLContext.wrap_bio(incoming, outgoing, server_side=False, \ |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1811 | server_hostname=None, session=None) |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 1812 | |
Christian Heimes | 4df60f1 | 2017-09-15 20:26:05 +0200 | [diff] [blame] | 1813 | Wrap the BIO objects *incoming* and *outgoing* and return an instance of |
| 1814 | attr:`SSLContext.sslobject_class` (default :class:`SSLObject`). The SSL |
| 1815 | routines will read input data from the incoming BIO and write data to the |
| 1816 | outgoing BIO. |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 1817 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 1818 | The *server_side*, *server_hostname* and *session* parameters have the |
| 1819 | same meaning as in :meth:`SSLContext.wrap_socket`. |
| 1820 | |
| 1821 | .. versionchanged:: 3.6 |
| 1822 | *session* argument was added. |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 1823 | |
Christian Heimes | 4df60f1 | 2017-09-15 20:26:05 +0200 | [diff] [blame] | 1824 | .. versionchanged:: 3.7 |
| 1825 | The method returns on instance of :attr:`SSLContext.sslobject_class` |
| 1826 | instead of hard-coded :class:`SSLObject`. |
| 1827 | |
| 1828 | .. attribute:: SSLContext.sslobject_class |
| 1829 | |
| 1830 | The return type of :meth:`SSLContext.wrap_bio`, defaults to |
| 1831 | :class:`SSLObject`. The attribute can be overridden on instance of class |
| 1832 | in order to return a custom subclass of :class:`SSLObject`. |
| 1833 | |
| 1834 | .. versionadded:: 3.7 |
| 1835 | |
Antoine Pitrou | b0182c8 | 2010-10-12 20:09:02 +0000 | [diff] [blame] | 1836 | .. method:: SSLContext.session_stats() |
| 1837 | |
| 1838 | Get statistics about the SSL sessions created or managed by this context. |
Sanyam Khurana | 338cd83 | 2018-01-20 05:55:37 +0530 | [diff] [blame] | 1839 | A dictionary is returned which maps the names of each `piece of information <https://www.openssl.org/docs/man1.1.0/ssl/SSL_CTX_sess_number.html>`_ to their |
Antoine Pitrou | b0182c8 | 2010-10-12 20:09:02 +0000 | [diff] [blame] | 1840 | numeric values. For example, here is the total number of hits and misses |
| 1841 | in the session cache since the context was created:: |
| 1842 | |
| 1843 | >>> stats = context.session_stats() |
| 1844 | >>> stats['hits'], stats['misses'] |
| 1845 | (0, 0) |
| 1846 | |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1847 | .. attribute:: SSLContext.check_hostname |
| 1848 | |
Berker Peksag | 315e104 | 2015-05-19 01:36:55 +0300 | [diff] [blame] | 1849 | Whether to match the peer cert's hostname with :func:`match_hostname` in |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1850 | :meth:`SSLSocket.do_handshake`. The context's |
| 1851 | :attr:`~SSLContext.verify_mode` must be set to :data:`CERT_OPTIONAL` or |
| 1852 | :data:`CERT_REQUIRED`, and you must pass *server_hostname* to |
Christian Heimes | e82c034 | 2017-09-15 20:29:57 +0200 | [diff] [blame] | 1853 | :meth:`~SSLContext.wrap_socket` in order to match the hostname. Enabling |
| 1854 | hostname checking automatically sets :attr:`~SSLContext.verify_mode` from |
| 1855 | :data:`CERT_NONE` to :data:`CERT_REQUIRED`. It cannot be set back to |
| 1856 | :data:`CERT_NONE` as long as hostname checking is enabled. |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1857 | |
| 1858 | Example:: |
| 1859 | |
| 1860 | import socket, ssl |
| 1861 | |
Benjamin Peterson | e9edee0 | 2018-02-20 21:55:01 -0800 | [diff] [blame] | 1862 | context = ssl.SSLContext() |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1863 | context.verify_mode = ssl.CERT_REQUIRED |
| 1864 | context.check_hostname = True |
| 1865 | context.load_default_certs() |
| 1866 | |
| 1867 | s = socket.socket(socket.AF_INET, socket.SOCK_STREAM) |
Berker Peksag | 38bf87c | 2014-07-17 05:00:36 +0300 | [diff] [blame] | 1868 | ssl_sock = context.wrap_socket(s, server_hostname='www.verisign.com') |
| 1869 | ssl_sock.connect(('www.verisign.com', 443)) |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1870 | |
| 1871 | .. versionadded:: 3.4 |
| 1872 | |
Christian Heimes | e82c034 | 2017-09-15 20:29:57 +0200 | [diff] [blame] | 1873 | .. versionchanged:: 3.7 |
| 1874 | |
| 1875 | :attr:`~SSLContext.verify_mode` is now automatically changed |
| 1876 | to :data:`CERT_REQUIRED` when hostname checking is enabled and |
| 1877 | :attr:`~SSLContext.verify_mode` is :data:`CERT_NONE`. Previously |
| 1878 | the same operation would have failed with a :exc:`ValueError`. |
| 1879 | |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 1880 | .. note:: |
| 1881 | |
| 1882 | This features requires OpenSSL 0.9.8f or newer. |
| 1883 | |
Christian Heimes | 698dde1 | 2018-02-27 11:54:43 +0100 | [diff] [blame] | 1884 | .. attribute:: SSLContext.maximum_version |
| 1885 | |
| 1886 | A :class:`TLSVersion` enum member representing the highest supported |
| 1887 | TLS version. The value defaults to :attr:`TLSVersion.MAXIMUM_SUPPORTED`. |
| 1888 | The attribute is read-only for protocols other than :attr:`PROTOCOL_TLS`, |
| 1889 | :attr:`PROTOCOL_TLS_CLIENT`, and :attr:`PROTOCOL_TLS_SERVER`. |
| 1890 | |
| 1891 | The attributes :attr:`~SSLContext.maximum_version`, |
| 1892 | :attr:`~SSLContext.minimum_version` and |
| 1893 | :attr:`SSLContext.options` all affect the supported SSL |
| 1894 | and TLS versions of the context. The implementation does not prevent |
| 1895 | invalid combination. For example a context with |
| 1896 | :attr:`OP_NO_TLSv1_2` in :attr:`~SSLContext.options` and |
| 1897 | :attr:`~SSLContext.maximum_version` set to :attr:`TLSVersion.TLSv1_2` |
| 1898 | will not be able to establish a TLS 1.2 connection. |
| 1899 | |
| 1900 | .. note:: |
| 1901 | |
| 1902 | This attribute is not available unless the ssl module is compiled |
| 1903 | with OpenSSL 1.1.0g or newer. |
| 1904 | |
| 1905 | .. attribute:: SSLContext.minimum_version |
| 1906 | |
| 1907 | Like :attr:`SSLContext.maximum_version` except it is the lowest |
| 1908 | supported version or :attr:`TLSVersion.MINIMUM_SUPPORTED`. |
| 1909 | |
| 1910 | .. note:: |
| 1911 | |
| 1912 | This attribute is not available unless the ssl module is compiled |
| 1913 | with OpenSSL 1.1.0g or newer. |
| 1914 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 1915 | .. attribute:: SSLContext.options |
| 1916 | |
| 1917 | An integer representing the set of SSL options enabled on this context. |
| 1918 | The default value is :data:`OP_ALL`, but you can specify other options |
| 1919 | such as :data:`OP_NO_SSLv2` by ORing them together. |
| 1920 | |
| 1921 | .. note:: |
| 1922 | With versions of OpenSSL older than 0.9.8m, it is only possible |
| 1923 | to set options, not to clear them. Attempting to clear an option |
| 1924 | (by resetting the corresponding bits) will raise a ``ValueError``. |
| 1925 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1926 | .. versionchanged:: 3.6 |
| 1927 | :attr:`SSLContext.options` returns :class:`Options` flags: |
| 1928 | |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 1929 | >>> ssl.create_default_context().options # doctest: +SKIP |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1930 | <Options.OP_ALL|OP_NO_SSLv3|OP_NO_SSLv2|OP_NO_COMPRESSION: 2197947391> |
| 1931 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1932 | .. attribute:: SSLContext.protocol |
| 1933 | |
| 1934 | The protocol version chosen when constructing the context. This attribute |
| 1935 | is read-only. |
| 1936 | |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 1937 | .. attribute:: SSLContext.hostname_checks_common_name |
| 1938 | |
| 1939 | Whether :attr:`~SSLContext.check_hostname` falls back to verify the cert's |
| 1940 | subject common name in the absence of a subject alternative name |
| 1941 | extension (default: true). |
| 1942 | |
| 1943 | .. versionadded:: 3.7 |
| 1944 | |
| 1945 | .. note:: |
| 1946 | Only writeable with OpenSSL 1.1.0 or higher. |
| 1947 | |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 1948 | .. attribute:: SSLContext.verify_flags |
| 1949 | |
| 1950 | The flags for certificate verification operations. You can set flags like |
| 1951 | :data:`VERIFY_CRL_CHECK_LEAF` by ORing them together. By default OpenSSL |
| 1952 | does neither require nor verify certificate revocation lists (CRLs). |
Christian Heimes | 2427b50 | 2013-11-23 11:24:32 +0100 | [diff] [blame] | 1953 | Available only with openssl version 0.9.8+. |
Christian Heimes | 2258779 | 2013-11-21 23:56:13 +0100 | [diff] [blame] | 1954 | |
| 1955 | .. versionadded:: 3.4 |
| 1956 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1957 | .. versionchanged:: 3.6 |
| 1958 | :attr:`SSLContext.verify_flags` returns :class:`VerifyFlags` flags: |
| 1959 | |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 1960 | >>> ssl.create_default_context().verify_flags # doctest: +SKIP |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1961 | <VerifyFlags.VERIFY_X509_TRUSTED_FIRST: 32768> |
| 1962 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1963 | .. attribute:: SSLContext.verify_mode |
| 1964 | |
| 1965 | Whether to try to verify other peers' certificates and how to behave |
| 1966 | if verification fails. This attribute must be one of |
| 1967 | :data:`CERT_NONE`, :data:`CERT_OPTIONAL` or :data:`CERT_REQUIRED`. |
| 1968 | |
Christian Heimes | 3aeacad | 2016-09-10 00:19:35 +0200 | [diff] [blame] | 1969 | .. versionchanged:: 3.6 |
| 1970 | :attr:`SSLContext.verify_mode` returns :class:`VerifyMode` enum: |
| 1971 | |
| 1972 | >>> ssl.create_default_context().verify_mode |
| 1973 | <VerifyMode.CERT_REQUIRED: 2> |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 1974 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 1975 | .. index:: single: certificates |
| 1976 | |
| 1977 | .. index:: single: X509 certificate |
| 1978 | |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 1979 | .. _ssl-certificates: |
| 1980 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 1981 | Certificates |
| 1982 | ------------ |
| 1983 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1984 | Certificates in general are part of a public-key / private-key system. In this |
| 1985 | system, each *principal*, (which may be a machine, or a person, or an |
| 1986 | organization) is assigned a unique two-part encryption key. One part of the key |
| 1987 | is public, and is called the *public key*; the other part is kept secret, and is |
| 1988 | called the *private key*. The two parts are related, in that if you encrypt a |
| 1989 | message with one of the parts, you can decrypt it with the other part, and |
| 1990 | **only** with the other part. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 1991 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1992 | A certificate contains information about two principals. It contains the name |
| 1993 | of a *subject*, and the subject's public key. It also contains a statement by a |
Andrés Delfino | 5092439 | 2018-06-18 01:34:30 -0300 | [diff] [blame] | 1994 | second principal, the *issuer*, that the subject is who they claim to be, and |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 1995 | that this is indeed the subject's public key. The issuer's statement is signed |
| 1996 | with the issuer's private key, which only the issuer knows. However, anyone can |
| 1997 | verify the issuer's statement by finding the issuer's public key, decrypting the |
| 1998 | statement with it, and comparing it to the other information in the certificate. |
| 1999 | The certificate also contains information about the time period over which it is |
| 2000 | valid. This is expressed as two fields, called "notBefore" and "notAfter". |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2001 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2002 | In the Python use of certificates, a client or server can use a certificate to |
| 2003 | prove who they are. The other side of a network connection can also be required |
| 2004 | to produce a certificate, and that certificate can be validated to the |
| 2005 | satisfaction of the client or server that requires such validation. The |
| 2006 | connection attempt can be set to raise an exception if the validation fails. |
| 2007 | Validation is done automatically, by the underlying OpenSSL framework; the |
| 2008 | application need not concern itself with its mechanics. But the application |
| 2009 | does usually need to provide sets of certificates to allow this process to take |
| 2010 | place. |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2011 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2012 | Python uses files to contain certificates. They should be formatted as "PEM" |
| 2013 | (see :rfc:`1422`), which is a base-64 encoded form wrapped with a header line |
| 2014 | and a footer line:: |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2015 | |
| 2016 | -----BEGIN CERTIFICATE----- |
| 2017 | ... (certificate in base64 PEM encoding) ... |
| 2018 | -----END CERTIFICATE----- |
| 2019 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2020 | Certificate chains |
| 2021 | ^^^^^^^^^^^^^^^^^^ |
| 2022 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2023 | The Python files which contain certificates can contain a sequence of |
| 2024 | certificates, sometimes called a *certificate chain*. This chain should start |
| 2025 | with the specific certificate for the principal who "is" the client or server, |
| 2026 | and then the certificate for the issuer of that certificate, and then the |
| 2027 | certificate for the issuer of *that* certificate, and so on up the chain till |
| 2028 | you get to a certificate which is *self-signed*, that is, a certificate which |
| 2029 | has the same subject and issuer, sometimes called a *root certificate*. The |
| 2030 | certificates should just be concatenated together in the certificate file. For |
| 2031 | example, suppose we had a three certificate chain, from our server certificate |
| 2032 | to the certificate of the certification authority that signed our server |
| 2033 | certificate, to the root certificate of the agency which issued the |
| 2034 | certification authority's certificate:: |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2035 | |
| 2036 | -----BEGIN CERTIFICATE----- |
| 2037 | ... (certificate for your server)... |
| 2038 | -----END CERTIFICATE----- |
| 2039 | -----BEGIN CERTIFICATE----- |
| 2040 | ... (the certificate for the CA)... |
| 2041 | -----END CERTIFICATE----- |
| 2042 | -----BEGIN CERTIFICATE----- |
| 2043 | ... (the root certificate for the CA's issuer)... |
| 2044 | -----END CERTIFICATE----- |
| 2045 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2046 | CA certificates |
| 2047 | ^^^^^^^^^^^^^^^ |
| 2048 | |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2049 | If you are going to require validation of the other side of the connection's |
| 2050 | certificate, you need to provide a "CA certs" file, filled with the certificate |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2051 | chains for each issuer you are willing to trust. Again, this file just contains |
| 2052 | these chains concatenated together. For validation, Python will use the first |
Donald Stufft | 4137465 | 2014-03-24 19:26:03 -0400 | [diff] [blame] | 2053 | chain it finds in the file which matches. The platform's certificates file can |
| 2054 | be used by calling :meth:`SSLContext.load_default_certs`, this is done |
| 2055 | automatically with :func:`.create_default_context`. |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2056 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2057 | Combined key and certificate |
| 2058 | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ |
| 2059 | |
| 2060 | Often the private key is stored in the same file as the certificate; in this |
| 2061 | case, only the ``certfile`` parameter to :meth:`SSLContext.load_cert_chain` |
| 2062 | and :func:`wrap_socket` needs to be passed. If the private key is stored |
| 2063 | with the certificate, it should come before the first certificate in |
| 2064 | the certificate chain:: |
| 2065 | |
| 2066 | -----BEGIN RSA PRIVATE KEY----- |
| 2067 | ... (private key in base64 encoding) ... |
| 2068 | -----END RSA PRIVATE KEY----- |
| 2069 | -----BEGIN CERTIFICATE----- |
| 2070 | ... (certificate in base64 PEM encoding) ... |
| 2071 | -----END CERTIFICATE----- |
| 2072 | |
| 2073 | Self-signed certificates |
| 2074 | ^^^^^^^^^^^^^^^^^^^^^^^^ |
| 2075 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2076 | If you are going to create a server that provides SSL-encrypted connection |
| 2077 | services, you will need to acquire a certificate for that service. There are |
| 2078 | many ways of acquiring appropriate certificates, such as buying one from a |
| 2079 | certification authority. Another common practice is to generate a self-signed |
| 2080 | certificate. The simplest way to do this is with the OpenSSL package, using |
| 2081 | something like the following:: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2082 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 2083 | % openssl req -new -x509 -days 365 -nodes -out cert.pem -keyout cert.pem |
| 2084 | Generating a 1024 bit RSA private key |
| 2085 | .......++++++ |
| 2086 | .............................++++++ |
| 2087 | writing new private key to 'cert.pem' |
| 2088 | ----- |
| 2089 | You are about to be asked to enter information that will be incorporated |
| 2090 | into your certificate request. |
| 2091 | What you are about to enter is what is called a Distinguished Name or a DN. |
| 2092 | There are quite a few fields but you can leave some blank |
| 2093 | For some fields there will be a default value, |
| 2094 | If you enter '.', the field will be left blank. |
| 2095 | ----- |
| 2096 | Country Name (2 letter code) [AU]:US |
| 2097 | State or Province Name (full name) [Some-State]:MyState |
| 2098 | Locality Name (eg, city) []:Some City |
| 2099 | Organization Name (eg, company) [Internet Widgits Pty Ltd]:My Organization, Inc. |
| 2100 | Organizational Unit Name (eg, section) []:My Group |
| 2101 | Common Name (eg, YOUR name) []:myserver.mygroup.myorganization.com |
| 2102 | Email Address []:ops@myserver.mygroup.myorganization.com |
| 2103 | % |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2104 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2105 | The disadvantage of a self-signed certificate is that it is its own root |
| 2106 | certificate, and no one else will have it in their cache of known (and trusted) |
| 2107 | root certificates. |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2108 | |
| 2109 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2110 | Examples |
| 2111 | -------- |
| 2112 | |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2113 | Testing for SSL support |
| 2114 | ^^^^^^^^^^^^^^^^^^^^^^^ |
| 2115 | |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2116 | To test for the presence of SSL support in a Python installation, user code |
| 2117 | should use the following idiom:: |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2118 | |
| 2119 | try: |
Georg Brandl | 8a7e5da | 2011-01-02 19:07:51 +0000 | [diff] [blame] | 2120 | import ssl |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2121 | except ImportError: |
Georg Brandl | 8a7e5da | 2011-01-02 19:07:51 +0000 | [diff] [blame] | 2122 | pass |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2123 | else: |
Serhiy Storchaka | dba9039 | 2016-05-10 12:01:23 +0300 | [diff] [blame] | 2124 | ... # do something that requires SSL support |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2125 | |
| 2126 | Client-side operation |
| 2127 | ^^^^^^^^^^^^^^^^^^^^^ |
| 2128 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2129 | This example creates a SSL context with the recommended security settings |
| 2130 | for client sockets, including automatic certificate verification:: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2131 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2132 | >>> context = ssl.create_default_context() |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2133 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2134 | If you prefer to tune security settings yourself, you might create |
| 2135 | a context from scratch (but beware that you might not get the settings |
| 2136 | right):: |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2137 | |
Benjamin Peterson | e9edee0 | 2018-02-20 21:55:01 -0800 | [diff] [blame] | 2138 | >>> context = ssl.SSLContext() |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2139 | >>> context.verify_mode = ssl.CERT_REQUIRED |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2140 | >>> context.check_hostname = True |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2141 | >>> context.load_verify_locations("/etc/ssl/certs/ca-bundle.crt") |
| 2142 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2143 | (this snippet assumes your operating system places a bundle of all CA |
| 2144 | certificates in ``/etc/ssl/certs/ca-bundle.crt``; if not, you'll get an |
| 2145 | error and have to adjust the location) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2146 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2147 | When you use the context to connect to a server, :const:`CERT_REQUIRED` |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2148 | validates the server certificate: it ensures that the server certificate |
| 2149 | was signed with one of the CA certificates, and checks the signature for |
| 2150 | correctness:: |
| 2151 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2152 | >>> conn = context.wrap_socket(socket.socket(socket.AF_INET), |
| 2153 | ... server_hostname="www.python.org") |
| 2154 | >>> conn.connect(("www.python.org", 443)) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2155 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2156 | You may then fetch the certificate:: |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2157 | |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2158 | >>> cert = conn.getpeercert() |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2159 | |
| 2160 | Visual inspection shows that the certificate does identify the desired service |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2161 | (that is, the HTTPS host ``www.python.org``):: |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2162 | |
| 2163 | >>> pprint.pprint(cert) |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2164 | {'OCSP': ('http://ocsp.digicert.com',), |
| 2165 | 'caIssuers': ('http://cacerts.digicert.com/DigiCertSHA2ExtendedValidationServerCA.crt',), |
| 2166 | 'crlDistributionPoints': ('http://crl3.digicert.com/sha2-ev-server-g1.crl', |
| 2167 | 'http://crl4.digicert.com/sha2-ev-server-g1.crl'), |
| 2168 | 'issuer': ((('countryName', 'US'),), |
| 2169 | (('organizationName', 'DigiCert Inc'),), |
| 2170 | (('organizationalUnitName', 'www.digicert.com'),), |
| 2171 | (('commonName', 'DigiCert SHA2 Extended Validation Server CA'),)), |
| 2172 | 'notAfter': 'Sep 9 12:00:00 2016 GMT', |
| 2173 | 'notBefore': 'Sep 5 00:00:00 2014 GMT', |
| 2174 | 'serialNumber': '01BB6F00122B177F36CAB49CEA8B6B26', |
| 2175 | 'subject': ((('businessCategory', 'Private Organization'),), |
| 2176 | (('1.3.6.1.4.1.311.60.2.1.3', 'US'),), |
| 2177 | (('1.3.6.1.4.1.311.60.2.1.2', 'Delaware'),), |
| 2178 | (('serialNumber', '3359300'),), |
| 2179 | (('streetAddress', '16 Allen Rd'),), |
| 2180 | (('postalCode', '03894-4801'),), |
| 2181 | (('countryName', 'US'),), |
| 2182 | (('stateOrProvinceName', 'NH'),), |
| 2183 | (('localityName', 'Wolfeboro,'),), |
| 2184 | (('organizationName', 'Python Software Foundation'),), |
| 2185 | (('commonName', 'www.python.org'),)), |
| 2186 | 'subjectAltName': (('DNS', 'www.python.org'), |
| 2187 | ('DNS', 'python.org'), |
Stéphane Wirtel | 19177fb | 2018-05-15 20:58:35 +0200 | [diff] [blame] | 2188 | ('DNS', 'pypi.org'), |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2189 | ('DNS', 'docs.python.org'), |
Stéphane Wirtel | 19177fb | 2018-05-15 20:58:35 +0200 | [diff] [blame] | 2190 | ('DNS', 'testpypi.org'), |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2191 | ('DNS', 'bugs.python.org'), |
| 2192 | ('DNS', 'wiki.python.org'), |
| 2193 | ('DNS', 'hg.python.org'), |
| 2194 | ('DNS', 'mail.python.org'), |
| 2195 | ('DNS', 'packaging.python.org'), |
| 2196 | ('DNS', 'pythonhosted.org'), |
| 2197 | ('DNS', 'www.pythonhosted.org'), |
| 2198 | ('DNS', 'test.pythonhosted.org'), |
| 2199 | ('DNS', 'us.pycon.org'), |
| 2200 | ('DNS', 'id.python.org')), |
Antoine Pitrou | 441ae04 | 2012-01-06 20:06:15 +0100 | [diff] [blame] | 2201 | 'version': 3} |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2202 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2203 | Now the SSL channel is established and the certificate verified, you can |
| 2204 | proceed to talk with the server:: |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2205 | |
Antoine Pitrou | dab6426 | 2010-09-19 13:31:06 +0000 | [diff] [blame] | 2206 | >>> conn.sendall(b"HEAD / HTTP/1.0\r\nHost: linuxfr.org\r\n\r\n") |
| 2207 | >>> pprint.pprint(conn.recv(1024).split(b"\r\n")) |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2208 | [b'HTTP/1.1 200 OK', |
| 2209 | b'Date: Sat, 18 Oct 2014 18:27:20 GMT', |
| 2210 | b'Server: nginx', |
| 2211 | b'Content-Type: text/html; charset=utf-8', |
| 2212 | b'X-Frame-Options: SAMEORIGIN', |
| 2213 | b'Content-Length: 45679', |
| 2214 | b'Accept-Ranges: bytes', |
| 2215 | b'Via: 1.1 varnish', |
| 2216 | b'Age: 2188', |
| 2217 | b'X-Served-By: cache-lcy1134-LCY', |
| 2218 | b'X-Cache: HIT', |
| 2219 | b'X-Cache-Hits: 11', |
| 2220 | b'Vary: Cookie', |
| 2221 | b'Strict-Transport-Security: max-age=63072000; includeSubDomains', |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2222 | b'Connection: close', |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2223 | b'', |
| 2224 | b''] |
| 2225 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2226 | See the discussion of :ref:`ssl-security` below. |
| 2227 | |
| 2228 | |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2229 | Server-side operation |
| 2230 | ^^^^^^^^^^^^^^^^^^^^^ |
| 2231 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2232 | For server operation, typically you'll need to have a server certificate, and |
| 2233 | private key, each in a file. You'll first create a context holding the key |
| 2234 | and the certificate, so that clients can check your authenticity. Then |
| 2235 | you'll open a socket, bind it to a port, call :meth:`listen` on it, and start |
| 2236 | waiting for clients to connect:: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2237 | |
| 2238 | import socket, ssl |
| 2239 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2240 | context = ssl.create_default_context(ssl.Purpose.CLIENT_AUTH) |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2241 | context.load_cert_chain(certfile="mycertfile", keyfile="mykeyfile") |
| 2242 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2243 | bindsocket = socket.socket() |
| 2244 | bindsocket.bind(('myaddr.mydomain.com', 10023)) |
| 2245 | bindsocket.listen(5) |
| 2246 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2247 | When a client connects, you'll call :meth:`accept` on the socket to get the |
| 2248 | new socket from the other end, and use the context's :meth:`SSLContext.wrap_socket` |
| 2249 | method to create a server-side SSL socket for the connection:: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2250 | |
| 2251 | while True: |
Georg Brandl | 8a7e5da | 2011-01-02 19:07:51 +0000 | [diff] [blame] | 2252 | newsocket, fromaddr = bindsocket.accept() |
| 2253 | connstream = context.wrap_socket(newsocket, server_side=True) |
| 2254 | try: |
| 2255 | deal_with_client(connstream) |
| 2256 | finally: |
Antoine Pitrou | b205d58 | 2011-01-02 22:09:27 +0000 | [diff] [blame] | 2257 | connstream.shutdown(socket.SHUT_RDWR) |
Georg Brandl | 8a7e5da | 2011-01-02 19:07:51 +0000 | [diff] [blame] | 2258 | connstream.close() |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2259 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2260 | Then you'll read data from the ``connstream`` and do something with it till you |
Georg Brandl | 7f01a13 | 2009-09-16 15:58:14 +0000 | [diff] [blame] | 2261 | are finished with the client (or the client is finished with you):: |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2262 | |
| 2263 | def deal_with_client(connstream): |
Georg Brandl | 8a7e5da | 2011-01-02 19:07:51 +0000 | [diff] [blame] | 2264 | data = connstream.recv(1024) |
| 2265 | # empty data means the client is finished with us |
| 2266 | while data: |
| 2267 | if not do_something(connstream, data): |
| 2268 | # we'll assume do_something returns False |
| 2269 | # when we're finished with client |
| 2270 | break |
| 2271 | data = connstream.recv(1024) |
| 2272 | # finished with client |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2273 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2274 | And go back to listening for new client connections (of course, a real server |
| 2275 | would probably handle each client connection in a separate thread, or put |
Victor Stinner | 2961145 | 2014-10-10 12:52:43 +0200 | [diff] [blame] | 2276 | the sockets in :ref:`non-blocking mode <ssl-nonblocking>` and use an event loop). |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2277 | |
| 2278 | |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2279 | .. _ssl-nonblocking: |
| 2280 | |
| 2281 | Notes on non-blocking sockets |
| 2282 | ----------------------------- |
| 2283 | |
Antoine Pitrou | b4bebda | 2014-04-29 10:03:28 +0200 | [diff] [blame] | 2284 | SSL sockets behave slightly different than regular sockets in |
| 2285 | non-blocking mode. When working with non-blocking sockets, there are |
| 2286 | thus several things you need to be aware of: |
| 2287 | |
| 2288 | - Most :class:`SSLSocket` methods will raise either |
| 2289 | :exc:`SSLWantWriteError` or :exc:`SSLWantReadError` instead of |
| 2290 | :exc:`BlockingIOError` if an I/O operation would |
| 2291 | block. :exc:`SSLWantReadError` will be raised if a read operation on |
| 2292 | the underlying socket is necessary, and :exc:`SSLWantWriteError` for |
| 2293 | a write operation on the underlying socket. Note that attempts to |
| 2294 | *write* to an SSL socket may require *reading* from the underlying |
| 2295 | socket first, and attempts to *read* from the SSL socket may require |
| 2296 | a prior *write* to the underlying socket. |
| 2297 | |
| 2298 | .. versionchanged:: 3.5 |
| 2299 | |
| 2300 | In earlier Python versions, the :meth:`!SSLSocket.send` method |
| 2301 | returned zero instead of raising :exc:`SSLWantWriteError` or |
| 2302 | :exc:`SSLWantReadError`. |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2303 | |
| 2304 | - Calling :func:`~select.select` tells you that the OS-level socket can be |
| 2305 | read from (or written to), but it does not imply that there is sufficient |
| 2306 | data at the upper SSL layer. For example, only part of an SSL frame might |
| 2307 | have arrived. Therefore, you must be ready to handle :meth:`SSLSocket.recv` |
| 2308 | and :meth:`SSLSocket.send` failures, and retry after another call to |
| 2309 | :func:`~select.select`. |
| 2310 | |
Antoine Pitrou | 75e0338 | 2014-05-18 00:55:13 +0200 | [diff] [blame] | 2311 | - Conversely, since the SSL layer has its own framing, a SSL socket may |
| 2312 | still have data available for reading without :func:`~select.select` |
| 2313 | being aware of it. Therefore, you should first call |
| 2314 | :meth:`SSLSocket.recv` to drain any potentially available data, and then |
| 2315 | only block on a :func:`~select.select` call if still necessary. |
| 2316 | |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2317 | (of course, similar provisions apply when using other primitives such as |
Antoine Pitrou | 75e0338 | 2014-05-18 00:55:13 +0200 | [diff] [blame] | 2318 | :func:`~select.poll`, or those in the :mod:`selectors` module) |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2319 | |
| 2320 | - The SSL handshake itself will be non-blocking: the |
| 2321 | :meth:`SSLSocket.do_handshake` method has to be retried until it returns |
| 2322 | successfully. Here is a synopsis using :func:`~select.select` to wait for |
| 2323 | the socket's readiness:: |
| 2324 | |
| 2325 | while True: |
| 2326 | try: |
| 2327 | sock.do_handshake() |
| 2328 | break |
Antoine Pitrou | 873bf26 | 2011-10-27 23:59:03 +0200 | [diff] [blame] | 2329 | except ssl.SSLWantReadError: |
| 2330 | select.select([sock], [], []) |
| 2331 | except ssl.SSLWantWriteError: |
| 2332 | select.select([], [sock], []) |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2333 | |
Victor Stinner | cfb2a0a | 2014-10-10 12:45:10 +0200 | [diff] [blame] | 2334 | .. seealso:: |
| 2335 | |
Victor Stinner | 2961145 | 2014-10-10 12:52:43 +0200 | [diff] [blame] | 2336 | The :mod:`asyncio` module supports :ref:`non-blocking SSL sockets |
| 2337 | <ssl-nonblocking>` and provides a |
Victor Stinner | cfb2a0a | 2014-10-10 12:45:10 +0200 | [diff] [blame] | 2338 | higher level API. It polls for events using the :mod:`selectors` module and |
| 2339 | handles :exc:`SSLWantWriteError`, :exc:`SSLWantReadError` and |
| 2340 | :exc:`BlockingIOError` exceptions. It runs the SSL handshake asynchronously |
| 2341 | as well. |
| 2342 | |
Antoine Pitrou | 6f5dcb1 | 2011-07-11 01:35:48 +0200 | [diff] [blame] | 2343 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2344 | Memory BIO Support |
| 2345 | ------------------ |
| 2346 | |
| 2347 | .. versionadded:: 3.5 |
| 2348 | |
| 2349 | Ever since the SSL module was introduced in Python 2.6, the :class:`SSLSocket` |
| 2350 | class has provided two related but distinct areas of functionality: |
| 2351 | |
| 2352 | - SSL protocol handling |
| 2353 | - Network IO |
| 2354 | |
| 2355 | The network IO API is identical to that provided by :class:`socket.socket`, |
| 2356 | from which :class:`SSLSocket` also inherits. This allows an SSL socket to be |
| 2357 | used as a drop-in replacement for a regular socket, making it very easy to add |
| 2358 | SSL support to an existing application. |
| 2359 | |
| 2360 | Combining SSL protocol handling and network IO usually works well, but there |
| 2361 | are some cases where it doesn't. An example is async IO frameworks that want to |
| 2362 | use a different IO multiplexing model than the "select/poll on a file |
| 2363 | descriptor" (readiness based) model that is assumed by :class:`socket.socket` |
| 2364 | and by the internal OpenSSL socket IO routines. This is mostly relevant for |
| 2365 | platforms like Windows where this model is not efficient. For this purpose, a |
| 2366 | reduced scope variant of :class:`SSLSocket` called :class:`SSLObject` is |
| 2367 | provided. |
| 2368 | |
| 2369 | .. class:: SSLObject |
| 2370 | |
| 2371 | A reduced-scope variant of :class:`SSLSocket` representing an SSL protocol |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2372 | instance that does not contain any network IO methods. This class is |
| 2373 | typically used by framework authors that want to implement asynchronous IO |
| 2374 | for SSL through memory buffers. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2375 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2376 | This class implements an interface on top of a low-level SSL object as |
| 2377 | implemented by OpenSSL. This object captures the state of an SSL connection |
| 2378 | but does not provide any network IO itself. IO needs to be performed through |
| 2379 | separate "BIO" objects which are OpenSSL's IO abstraction layer. |
| 2380 | |
Christian Heimes | 9d50ab5 | 2018-02-27 10:17:30 +0100 | [diff] [blame] | 2381 | This class has no public constructor. An :class:`SSLObject` instance |
| 2382 | must be created using the :meth:`~SSLContext.wrap_bio` method. This |
| 2383 | method will create the :class:`SSLObject` instance and bind it to a |
| 2384 | pair of BIOs. The *incoming* BIO is used to pass data from Python to the |
| 2385 | SSL protocol instance, while the *outgoing* BIO is used to pass data the |
| 2386 | other way around. |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2387 | |
| 2388 | The following methods are available: |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2389 | |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 2390 | - :attr:`~SSLSocket.context` |
| 2391 | - :attr:`~SSLSocket.server_side` |
| 2392 | - :attr:`~SSLSocket.server_hostname` |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 2393 | - :attr:`~SSLSocket.session` |
| 2394 | - :attr:`~SSLSocket.session_reused` |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 2395 | - :meth:`~SSLSocket.read` |
| 2396 | - :meth:`~SSLSocket.write` |
| 2397 | - :meth:`~SSLSocket.getpeercert` |
| 2398 | - :meth:`~SSLSocket.selected_npn_protocol` |
| 2399 | - :meth:`~SSLSocket.cipher` |
Benjamin Peterson | 4cb1781 | 2015-01-07 11:14:26 -0600 | [diff] [blame] | 2400 | - :meth:`~SSLSocket.shared_ciphers` |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 2401 | - :meth:`~SSLSocket.compression` |
| 2402 | - :meth:`~SSLSocket.pending` |
| 2403 | - :meth:`~SSLSocket.do_handshake` |
| 2404 | - :meth:`~SSLSocket.unwrap` |
| 2405 | - :meth:`~SSLSocket.get_channel_binding` |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2406 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2407 | When compared to :class:`SSLSocket`, this object lacks the following |
| 2408 | features: |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2409 | |
Benjamin Peterson | fdfca5f | 2017-06-11 00:24:38 -0700 | [diff] [blame] | 2410 | - Any form of network IO; ``recv()`` and ``send()`` read and write only to |
| 2411 | the underlying :class:`MemoryBIO` buffers. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2412 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2413 | - There is no *do_handshake_on_connect* machinery. You must always manually |
| 2414 | call :meth:`~SSLSocket.do_handshake` to start the handshake. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2415 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2416 | - There is no handling of *suppress_ragged_eofs*. All end-of-file conditions |
| 2417 | that are in violation of the protocol are reported via the |
| 2418 | :exc:`SSLEOFError` exception. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2419 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2420 | - The method :meth:`~SSLSocket.unwrap` call does not return anything, |
| 2421 | unlike for an SSL socket where it returns the underlying socket. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2422 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2423 | - The *server_name_callback* callback passed to |
| 2424 | :meth:`SSLContext.set_servername_callback` will get an :class:`SSLObject` |
| 2425 | instance instead of a :class:`SSLSocket` instance as its first parameter. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2426 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2427 | Some notes related to the use of :class:`SSLObject`: |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2428 | |
Victor Stinner | 2debf15 | 2014-10-10 13:04:08 +0200 | [diff] [blame] | 2429 | - All IO on an :class:`SSLObject` is :ref:`non-blocking <ssl-nonblocking>`. |
| 2430 | This means that for example :meth:`~SSLSocket.read` will raise an |
| 2431 | :exc:`SSLWantReadError` if it needs more data than the incoming BIO has |
| 2432 | available. |
| 2433 | |
| 2434 | - There is no module-level ``wrap_bio()`` call like there is for |
| 2435 | :meth:`~SSLContext.wrap_socket`. An :class:`SSLObject` is always created |
| 2436 | via an :class:`SSLContext`. |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2437 | |
Christian Heimes | 9d50ab5 | 2018-02-27 10:17:30 +0100 | [diff] [blame] | 2438 | .. versionchanged:: 3.7 |
| 2439 | :class:`SSLObject` instances must to created with |
| 2440 | :meth:`~SSLContext.wrap_bio`. In earlier versions, it was possible to |
| 2441 | create instances directly. This was never documented or officially |
| 2442 | supported. |
| 2443 | |
Victor Stinner | 805b262 | 2014-10-10 12:49:08 +0200 | [diff] [blame] | 2444 | An SSLObject communicates with the outside world using memory buffers. The |
| 2445 | class :class:`MemoryBIO` provides a memory buffer that can be used for this |
| 2446 | purpose. It wraps an OpenSSL memory BIO (Basic IO) object: |
| 2447 | |
| 2448 | .. class:: MemoryBIO |
| 2449 | |
| 2450 | A memory buffer that can be used to pass data between Python and an SSL |
| 2451 | protocol instance. |
| 2452 | |
| 2453 | .. attribute:: MemoryBIO.pending |
| 2454 | |
| 2455 | Return the number of bytes currently in the memory buffer. |
| 2456 | |
| 2457 | .. attribute:: MemoryBIO.eof |
| 2458 | |
| 2459 | A boolean indicating whether the memory BIO is current at the end-of-file |
| 2460 | position. |
| 2461 | |
| 2462 | .. method:: MemoryBIO.read(n=-1) |
| 2463 | |
| 2464 | Read up to *n* bytes from the memory buffer. If *n* is not specified or |
| 2465 | negative, all bytes are returned. |
| 2466 | |
| 2467 | .. method:: MemoryBIO.write(buf) |
| 2468 | |
| 2469 | Write the bytes from *buf* to the memory BIO. The *buf* argument must be an |
| 2470 | object supporting the buffer protocol. |
| 2471 | |
| 2472 | The return value is the number of bytes written, which is always equal to |
| 2473 | the length of *buf*. |
| 2474 | |
| 2475 | .. method:: MemoryBIO.write_eof() |
| 2476 | |
| 2477 | Write an EOF marker to the memory BIO. After this method has been called, it |
| 2478 | is illegal to call :meth:`~MemoryBIO.write`. The attribute :attr:`eof` will |
| 2479 | become true after all data currently in the buffer has been read. |
| 2480 | |
Antoine Pitrou | b1fdf47 | 2014-10-05 20:41:53 +0200 | [diff] [blame] | 2481 | |
Christian Heimes | 99a6570 | 2016-09-10 23:44:53 +0200 | [diff] [blame] | 2482 | SSL session |
| 2483 | ----------- |
| 2484 | |
| 2485 | .. versionadded:: 3.6 |
| 2486 | |
| 2487 | .. class:: SSLSession |
| 2488 | |
| 2489 | Session object used by :attr:`~SSLSocket.session`. |
| 2490 | |
| 2491 | .. attribute:: id |
| 2492 | .. attribute:: time |
| 2493 | .. attribute:: timeout |
| 2494 | .. attribute:: ticket_lifetime_hint |
| 2495 | .. attribute:: has_ticket |
| 2496 | |
| 2497 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2498 | .. _ssl-security: |
| 2499 | |
| 2500 | Security considerations |
| 2501 | ----------------------- |
| 2502 | |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2503 | Best defaults |
| 2504 | ^^^^^^^^^^^^^ |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2505 | |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2506 | For **client use**, if you don't have any special requirements for your |
| 2507 | security policy, it is highly recommended that you use the |
| 2508 | :func:`create_default_context` function to create your SSL context. |
| 2509 | It will load the system's trusted CA certificates, enable certificate |
Antoine Pitrou | f8cbbbb | 2014-03-23 16:31:08 +0100 | [diff] [blame] | 2510 | validation and hostname checking, and try to choose reasonably secure |
| 2511 | protocol and cipher settings. |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2512 | |
| 2513 | For example, here is how you would use the :class:`smtplib.SMTP` class to |
| 2514 | create a trusted, secure connection to a SMTP server:: |
| 2515 | |
| 2516 | >>> import ssl, smtplib |
| 2517 | >>> smtp = smtplib.SMTP("mail.python.org", port=587) |
| 2518 | >>> context = ssl.create_default_context() |
| 2519 | >>> smtp.starttls(context=context) |
| 2520 | (220, b'2.0.0 Ready to start TLS') |
| 2521 | |
| 2522 | If a client certificate is needed for the connection, it can be added with |
| 2523 | :meth:`SSLContext.load_cert_chain`. |
| 2524 | |
| 2525 | By contrast, if you create the SSL context by calling the :class:`SSLContext` |
Antoine Pitrou | f8cbbbb | 2014-03-23 16:31:08 +0100 | [diff] [blame] | 2526 | constructor yourself, it will not have certificate validation nor hostname |
| 2527 | checking enabled by default. If you do so, please read the paragraphs below |
| 2528 | to achieve a good security level. |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2529 | |
| 2530 | Manual settings |
| 2531 | ^^^^^^^^^^^^^^^ |
| 2532 | |
| 2533 | Verifying certificates |
| 2534 | '''''''''''''''''''''' |
| 2535 | |
Donald Stufft | 8b852f1 | 2014-05-20 12:58:38 -0400 | [diff] [blame] | 2536 | When calling the :class:`SSLContext` constructor directly, |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2537 | :const:`CERT_NONE` is the default. Since it does not authenticate the other |
| 2538 | peer, it can be insecure, especially in client mode where most of time you |
| 2539 | would like to ensure the authenticity of the server you're talking to. |
| 2540 | Therefore, when in client mode, it is highly recommended to use |
| 2541 | :const:`CERT_REQUIRED`. However, it is in itself not sufficient; you also |
Antoine Pitrou | 59fdd67 | 2010-10-08 10:37:08 +0000 | [diff] [blame] | 2542 | have to check that the server certificate, which can be obtained by calling |
| 2543 | :meth:`SSLSocket.getpeercert`, matches the desired service. For many |
| 2544 | protocols and applications, the service can be identified by the hostname; |
Christian Heimes | 1aa9a75 | 2013-12-02 02:41:19 +0100 | [diff] [blame] | 2545 | in this case, the :func:`match_hostname` function can be used. This common |
| 2546 | check is automatically performed when :attr:`SSLContext.check_hostname` is |
| 2547 | enabled. |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2548 | |
Christian Heimes | 61d478c | 2018-01-27 15:51:38 +0100 | [diff] [blame] | 2549 | .. versionchanged:: 3.7 |
| 2550 | Hostname matchings is now performed by OpenSSL. Python no longer uses |
| 2551 | :func:`match_hostname`. |
| 2552 | |
Antoine Pitrou | 152efa2 | 2010-05-16 18:19:27 +0000 | [diff] [blame] | 2553 | In server mode, if you want to authenticate your clients using the SSL layer |
| 2554 | (rather than using a higher-level authentication mechanism), you'll also have |
| 2555 | to specify :const:`CERT_REQUIRED` and similarly check the client certificate. |
| 2556 | |
Thomas Wouters | ed03b41 | 2007-08-28 21:37:11 +0000 | [diff] [blame] | 2557 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 2558 | Protocol versions |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2559 | ''''''''''''''''' |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 2560 | |
Antoine Pitrou | 4b4ddb2 | 2014-10-21 00:14:39 +0200 | [diff] [blame] | 2561 | SSL versions 2 and 3 are considered insecure and are therefore dangerous to |
| 2562 | use. If you want maximum compatibility between clients and servers, it is |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 2563 | recommended to use :const:`PROTOCOL_TLS_CLIENT` or |
| 2564 | :const:`PROTOCOL_TLS_SERVER` as the protocol version. SSLv2 and SSLv3 are |
| 2565 | disabled by default. |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 2566 | |
Marco Buttu | 7b2491a | 2017-04-13 16:17:59 +0200 | [diff] [blame] | 2567 | :: |
| 2568 | |
Christian Heimes | c4d2e50 | 2016-09-12 01:14:35 +0200 | [diff] [blame] | 2569 | >>> client_context = ssl.SSLContext(ssl.PROTOCOL_TLS_CLIENT) |
| 2570 | >>> client_context.options |= ssl.OP_NO_TLSv1 |
| 2571 | >>> client_context.options |= ssl.OP_NO_TLSv1_1 |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 2572 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 2573 | |
Christian Heimes | 598894f | 2016-09-05 23:19:05 +0200 | [diff] [blame] | 2574 | The SSL context created above will only allow TLSv1.2 and later (if |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 2575 | supported by your system) connections to a server. :const:`PROTOCOL_TLS_CLIENT` |
| 2576 | implies certificate validation and hostname checks by default. You have to |
| 2577 | load certificates into the context. |
| 2578 | |
Antoine Pitrou | b521877 | 2010-05-21 09:56:06 +0000 | [diff] [blame] | 2579 | |
Antoine Pitrou | b7ffed8 | 2012-01-04 02:53:44 +0100 | [diff] [blame] | 2580 | Cipher selection |
Antoine Pitrou | c5e075f | 2014-03-22 18:19:11 +0100 | [diff] [blame] | 2581 | '''''''''''''''' |
Antoine Pitrou | b7ffed8 | 2012-01-04 02:53:44 +0100 | [diff] [blame] | 2582 | |
| 2583 | If you have advanced security requirements, fine-tuning of the ciphers |
| 2584 | enabled when negotiating a SSL session is possible through the |
| 2585 | :meth:`SSLContext.set_ciphers` method. Starting from Python 3.2.3, the |
| 2586 | ssl module disables certain weak ciphers by default, but you may want |
Donald Stufft | 79ccaa2 | 2014-03-21 21:33:34 -0400 | [diff] [blame] | 2587 | to further restrict the cipher choice. Be sure to read OpenSSL's documentation |
Sanyam Khurana | 338cd83 | 2018-01-20 05:55:37 +0530 | [diff] [blame] | 2588 | about the `cipher list format <https://www.openssl.org/docs/manmaster/man1/ciphers.html#CIPHER-LIST-FORMAT>`_. |
Christian Heimes | 5fe668c | 2016-09-12 00:01:11 +0200 | [diff] [blame] | 2589 | If you want to check which ciphers are enabled by a given cipher list, use |
| 2590 | :meth:`SSLContext.get_ciphers` or the ``openssl ciphers`` command on your |
| 2591 | system. |
Antoine Pitrou | b7ffed8 | 2012-01-04 02:53:44 +0100 | [diff] [blame] | 2592 | |
Antoine Pitrou | 9eefe91 | 2013-11-17 15:35:33 +0100 | [diff] [blame] | 2593 | Multi-processing |
| 2594 | ^^^^^^^^^^^^^^^^ |
| 2595 | |
| 2596 | If using this module as part of a multi-processed application (using, |
| 2597 | for example the :mod:`multiprocessing` or :mod:`concurrent.futures` modules), |
| 2598 | be aware that OpenSSL's internal random number generator does not properly |
| 2599 | handle forked processes. Applications must change the PRNG state of the |
| 2600 | parent process if they use any SSL feature with :func:`os.fork`. Any |
| 2601 | successful call of :func:`~ssl.RAND_add`, :func:`~ssl.RAND_bytes` or |
| 2602 | :func:`~ssl.RAND_pseudo_bytes` is sufficient. |
| 2603 | |
Georg Brandl | 48310cd | 2009-01-03 21:18:54 +0000 | [diff] [blame] | 2604 | |
Christian Heimes | 529525f | 2018-05-23 22:24:45 +0200 | [diff] [blame] | 2605 | .. _ssl-tlsv1_3: |
| 2606 | |
| 2607 | TLS 1.3 |
| 2608 | ------- |
| 2609 | |
| 2610 | .. versionadded:: 3.7 |
| 2611 | |
| 2612 | Python has provisional and experimental support for TLS 1.3 with OpenSSL |
| 2613 | 1.1.1. The new protocol behaves slightly differently than previous version |
| 2614 | of TLS/SSL. Some new TLS 1.3 features are not yet available. |
| 2615 | |
| 2616 | - TLS 1.3 uses a disjunct set of cipher suites. All AES-GCM and |
| 2617 | ChaCha20 cipher suites are enabled by default. The method |
| 2618 | :meth:`SSLContext.set_ciphers` cannot enable or disable any TLS 1.3 |
| 2619 | ciphers yet, but :meth:`SSLContext.get_cipers` returns them. |
| 2620 | - Session tickets are no longer sent as part of the initial handshake and |
| 2621 | are handled differently. :attr:`SSLSocket.session` and :class:`SSLSession` |
| 2622 | are not compatible with TLS 1.3. |
| 2623 | - Client-side certificates are also no longer verified during the initial |
| 2624 | handshake. A server can request a certificate at any time. Clients |
| 2625 | process certificate requests while they send or receive application data |
| 2626 | from the server. |
| 2627 | - TLS 1.3 features like early data, deferred TLS client cert request, |
| 2628 | signature algorithm configuration, and rekeying are not supported yet. |
| 2629 | |
| 2630 | |
| 2631 | .. _ssl-libressl: |
Christian Heimes | 6cdb795 | 2018-02-24 22:12:40 +0100 | [diff] [blame] | 2632 | |
| 2633 | LibreSSL support |
| 2634 | ---------------- |
| 2635 | |
| 2636 | LibreSSL is a fork of OpenSSL 1.0.1. The ssl module has limited support for |
| 2637 | LibreSSL. Some features are not available when the ssl module is compiled |
| 2638 | with LibreSSL. |
| 2639 | |
| 2640 | * LibreSSL >= 2.6.1 no longer supports NPN. The methods |
| 2641 | :meth:`SSLContext.set_npn_protocols` and |
| 2642 | :meth:`SSLSocket.selected_npn_protocol` are not available. |
| 2643 | * :meth:`SSLContext.set_default_verify_paths` ignores the env vars |
| 2644 | :envvar:`SSL_CERT_FILE` and :envvar:`SSL_CERT_PATH` although |
| 2645 | :func:`get_default_verify_paths` still reports them. |
| 2646 | |
| 2647 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 2648 | .. seealso:: |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2649 | |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 2650 | Class :class:`socket.socket` |
Georg Brandl | 4a6cf6c | 2013-10-06 18:20:31 +0200 | [diff] [blame] | 2651 | Documentation of underlying :mod:`socket` class |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2652 | |
Georg Brandl | 5d94134 | 2016-02-26 19:37:12 +0100 | [diff] [blame] | 2653 | `SSL/TLS Strong Encryption: An Introduction <https://httpd.apache.org/docs/trunk/en/ssl/ssl_intro.html>`_ |
Matt Eaton | 9cf8c42 | 2018-03-10 19:00:04 -0600 | [diff] [blame] | 2654 | Intro from the Apache HTTP Server documentation |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2655 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2656 | :rfc:`RFC 1422: Privacy Enhancement for Internet Electronic Mail: Part II: Certificate-Based Key Management <1422>` |
Thomas Wouters | 1b7f891 | 2007-09-19 03:06:30 +0000 | [diff] [blame] | 2657 | Steve Kent |
Thomas Wouters | 47b49bf | 2007-08-30 22:15:33 +0000 | [diff] [blame] | 2658 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2659 | :rfc:`RFC 4086: Randomness Requirements for Security <4086>` |
Chandan Kumar | 63c2c8a | 2017-06-09 15:13:58 +0530 | [diff] [blame] | 2660 | Donald E., Jeffrey I. Schiller |
Thomas Wouters | 89d996e | 2007-09-08 17:39:28 +0000 | [diff] [blame] | 2661 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2662 | :rfc:`RFC 5280: Internet X.509 Public Key Infrastructure Certificate and Certificate Revocation List (CRL) Profile <5280>` |
Chandan Kumar | 63c2c8a | 2017-06-09 15:13:58 +0530 | [diff] [blame] | 2663 | D. Cooper |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 2664 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2665 | :rfc:`RFC 5246: The Transport Layer Security (TLS) Protocol Version 1.2 <5246>` |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 2666 | T. Dierks et. al. |
| 2667 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2668 | :rfc:`RFC 6066: Transport Layer Security (TLS) Extensions <6066>` |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 2669 | D. Eastlake |
| 2670 | |
Serhiy Storchaka | 6dff020 | 2016-05-07 10:49:07 +0300 | [diff] [blame] | 2671 | `IANA TLS: Transport Layer Security (TLS) Parameters <https://www.iana.org/assignments/tls-parameters/tls-parameters.xml>`_ |
Antoine Pitrou | 58ddc9d | 2013-01-05 21:20:29 +0100 | [diff] [blame] | 2672 | IANA |
Christian Heimes | ad0ffa0 | 2017-09-06 16:19:56 -0700 | [diff] [blame] | 2673 | |
Serhiy Storchaka | 0a36ac1 | 2018-05-31 07:39:00 +0300 | [diff] [blame] | 2674 | :rfc:`RFC 7525: Recommendations for Secure Use of Transport Layer Security (TLS) and Datagram Transport Layer Security (DTLS) <7525>` |
Christian Heimes | ad0ffa0 | 2017-09-06 16:19:56 -0700 | [diff] [blame] | 2675 | IETF |
| 2676 | |
| 2677 | `Mozilla's Server Side TLS recommendations <https://wiki.mozilla.org/Security/Server_Side_TLS>`_ |
| 2678 | Mozilla |