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Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001\documentclass{howto}
2
3\title{Python OpenSSL Manual}
4
Jean-Paul Calderone71ff3682009-04-25 08:30:11 -04005\release{0.9}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05006
Jean-Paul Calderone0ebe45a2009-04-25 10:40:31 -04007\author{Jean-Paul Calderone}
8\authoraddress{\email{exarkun@twistedmatrix.com}}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05009
10\usepackage[english]{babel}
11\usepackage[T1]{fontenc}
12
13\begin{document}
14
15\maketitle
16
17\begin{abstract}
18\noindent
19This module is a rather thin wrapper around (a subset of) the OpenSSL library.
20With thin wrapper I mean that a lot of the object methods do nothing more than
21calling a corresponding function in the OpenSSL library.
22\end{abstract}
23
24\tableofcontents
25
26
27\section{Introduction \label{intro}}
28
Jean-Paul Calderone9450d5b2008-09-01 12:04:20 -040029The reason pyOpenSSL was created is that the SSL support in the socket module
30in Python 2.1 (the contemporary version of Python when the pyOpenSSL project
31was begun) was severely limited. Other OpenSSL wrappers for Python at the time
32were also limited, though in different ways. Unfortunately, Python's standard
33library SSL support has remained weak, although other packages (such as
34M2Crypto\footnote{See \url{http://chandlerproject.org/Projects/MeTooCrypto}})
35have made great advances and now equal or exceed pyOpenSSL's functionality.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -050036
Jean-Paul Calderone9450d5b2008-09-01 12:04:20 -040037The reason pyOpenSSL continues to be maintained is that there is a significant
38user community around it, as well as a large amount of software which depends
39on it. It is a great benefit to many people for pyOpenSSL to continue to exist
40and advance.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -050041
42\section{Building and Installing \label{building}}
43
44These instructions can also be found in the file \verb|INSTALL|.
45
46I have tested this on Debian Linux systems (woody and sid), Solaris 2.6 and
472.7. Others have successfully compiled it on Windows and NT.
48
49\subsection{Building the Module on a Unix System \label{building-unix}}
50
51pyOpenSSL uses distutils, so there really shouldn't be any problems. To build
52the library:
53\begin{verbatim}
54python setup.py build
55\end{verbatim}
56
57If your OpenSSL header files aren't in \verb|/usr/include|, you may need to
58supply the \verb|-I| flag to let the setup script know where to look. The same
59goes for the libraries of course, use the \verb|-L| flag. Note that
60\verb|build| won't accept these flags, so you have to run first
61\verb|build_ext| and then \verb|build|! Example:
62\begin{verbatim}
63python setup.py build_ext -I/usr/local/ssl/include -L/usr/local/ssl/lib
64python setup.py build
65\end{verbatim}
66
67Now you should have a directory called \verb|OpenSSL| that contains e.g.
68\verb|SSL.so| and \verb|__init__.py| somewhere in the build dicrectory,
69so just:
70\begin{verbatim}
71python setup.py install
72\end{verbatim}
73
74If you, for some arcane reason, don't want the module to appear in the
75\verb|site-packages| directory, use the \verb|--prefix| option.
76
77You can, of course, do
78\begin{verbatim}
79python setup.py --help
80\end{verbatim}
81
82to find out more about how to use the script.
83
84\subsection{Building the Module on a Windows System \label{building-windows}}
85
86Big thanks to Itamar Shtull-Trauring and Oleg Orlov for their help with
87Windows build instructions. Same as for Unix systems, we have to separate
88the \verb|build_ext| and the \verb|build|.
89
90Building the library:
91
92\begin{verbatim}
93setup.py build_ext -I ...\openssl\inc32 -L ...\openssl\out32dll
94setup.py build
95\end{verbatim}
96
97Where \verb|...\openssl| is of course the location of your OpenSSL installation.
98
99Installation is the same as for Unix systems:
100\begin{verbatim}
101setup.py install
102\end{verbatim}
103
104And similarily, you can do
105\begin{verbatim}
106setup.py --help
107\end{verbatim}
108
109to get more information.
110
111
112\section{\module{OpenSSL} --- Python interface to OpenSSL \label{openssl}}
113
114\declaremodule{extension}{OpenSSL}
115\modulesynopsis{Python interface to OpenSSL}
116
117This package provides a high-level interface to the functions in the
118OpenSSL library. The following modules are defined:
119
120\begin{datadesc}{crypto}
121Generic cryptographic module. Note that if anything is incomplete, this module is!
122\end{datadesc}
123
124\begin{datadesc}{rand}
125An interface to the OpenSSL pseudo random number generator.
126\end{datadesc}
127
128\begin{datadesc}{SSL}
129An interface to the SSL-specific parts of OpenSSL.
130\end{datadesc}
131
132
133% % % crypto moduleOpenSSL
134
135\subsection{\module{crypto} --- Generic cryptographic module \label{openssl-crypto}}
136
137\declaremodule{extension}{crypto}
138\modulesynopsis{Generic cryptographic module}
139
140\begin{datadesc}{X509Type}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400141See \class{X509}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500142\end{datadesc}
143
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400144\begin{classdesc}{X509}{}
145A class representing X.509 certificates.
146\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500147
148\begin{datadesc}{X509NameType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400149See \class{X509Name}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500150\end{datadesc}
151
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400152\begin{classdesc}{X509Name}{x509name}
153A class representing X.509 Distinguished Names.
154
155This constructor creates a copy of \var{x509name} which should be an
156instance of \class{X509Name}.
157\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500158
159\begin{datadesc}{X509ReqType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400160See \class{X509Req}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500161\end{datadesc}
162
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400163\begin{classdesc}{X509Req}{}
164A class representing X.509 certificate requests.
165\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500166
167\begin{datadesc}{X509StoreType}
168A Python type object representing the X509Store object type.
169\end{datadesc}
170
171\begin{datadesc}{PKeyType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400172See \class{PKey}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500173\end{datadesc}
174
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400175\begin{classdesc}{PKey}{}
176A class representing DSA or RSA keys.
177\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500178
179\begin{datadesc}{PKCS7Type}
180A Python type object representing the PKCS7 object type.
181\end{datadesc}
182
183\begin{datadesc}{PKCS12Type}
184A Python type object representing the PKCS12 object type.
185\end{datadesc}
186
187\begin{datadesc}{X509ExtensionType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400188See \class{X509Extension}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500189\end{datadesc}
190
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400191\begin{classdesc}{X509Extension}{typename, critical, value}
192A class representing an X.509 v3 certificate extensions.
193\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500194
195\begin{datadesc}{NetscapeSPKIType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400196See \class{NetscapeSPKI}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500197\end{datadesc}
198
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400199\begin{classdesc}{NetscapeSPKI}{\optional{enc}}
200A class representing Netscape SPKI objects.
201
202If the \var{enc} argument is present, it should be a base64-encoded string
203representing a NetscapeSPKI object, as returned by the \method{b64_encode}
204method.
205\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500206
207\begin{datadesc}{FILETYPE_PEM}
208\dataline{FILETYPE_ASN1}
209File type constants.
210\end{datadesc}
211
212\begin{datadesc}{TYPE_RSA}
213\dataline{TYPE_DSA}
214Key type constants.
215\end{datadesc}
216
217\begin{excdesc}{Error}
218Generic exception used in the \module{crypto} module.
219\end{excdesc}
220
221\begin{funcdesc}{dump_certificate}{type, cert}
222Dump the certificate \var{cert} into a buffer string encoded with the type
223\var{type}.
224\end{funcdesc}
225
226\begin{funcdesc}{dump_certificate_request}{type, req}
227Dump the certificate request \var{req} into a buffer string encoded with the
228type \var{type}.
229\end{funcdesc}
230
231\begin{funcdesc}{dump_privatekey}{type, pkey\optional{, cipher, passphrase}}
232Dump the private key \var{pkey} into a buffer string encoded with the type
233\var{type}, optionally (if \var{type} is \constant{FILETYPE_PEM}) encrypting it
234using \var{cipher} and \var{passphrase}.
235
236\var{passphrase} must be either a string or a callback for providing the
237pass phrase.
238\end{funcdesc}
239
240\begin{funcdesc}{load_certificate}{type, buffer}
241Load a certificate (X509) from the string \var{buffer} encoded with the
242type \var{type}.
243\end{funcdesc}
244
245\begin{funcdesc}{load_certificate_request}{type, buffer}
246Load a certificate request (X509Req) from the string \var{buffer} encoded with
247the type \var{type}.
248\end{funcdesc}
249
250\begin{funcdesc}{load_privatekey}{type, buffer\optional{, passphrase}}
251Load a private key (PKey) from the string \var{buffer} encoded with
252the type \var{type} (must be one of \constant{FILETYPE_PEM} and
253\constant{FILETYPE_ASN1}).
254
255\var{passphrase} must be either a string or a callback for providing the
256pass phrase.
257\end{funcdesc}
258
259\begin{funcdesc}{load_pkcs7_data}{type, buffer}
260Load pkcs7 data from the string \var{buffer} encoded with the type \var{type}.
261\end{funcdesc}
262
263\begin{funcdesc}{load_pkcs12}{buffer\optional{, passphrase}}
264Load pkcs12 data from the string \var{buffer}. If the pkcs12 structure is
Rick Deanf94096c2009-07-18 14:23:06 -0500265encrypted, a \var{passphrase} must be included. The MAC is always
Rick Dean42d69e12009-07-20 11:36:08 -0500266checked and thus required.
267
268See also the man page for the C function \function{PKCS12_parse}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500269\end{funcdesc}
270
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500271\subsubsection{X509 objects \label{openssl-x509}}
272
273X509 objects have the following methods:
274
275\begin{methoddesc}[X509]{get_issuer}{}
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500276Return an X509Name object representing the issuer of the certificate.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500277\end{methoddesc}
278
279\begin{methoddesc}[X509]{get_pubkey}{}
280Return a PKey object representing the public key of the certificate.
281\end{methoddesc}
282
283\begin{methoddesc}[X509]{get_serial_number}{}
284Return the certificate serial number.
285\end{methoddesc}
286
287\begin{methoddesc}[X509]{get_subject}{}
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500288Return an X509Name object representing the subject of the certificate.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500289\end{methoddesc}
290
291\begin{methoddesc}[X509]{get_version}{}
292Return the certificate version.
293\end{methoddesc}
294
Jean-Paul Calderone525ef802008-03-09 20:39:42 -0400295\begin{methoddesc}[X509]{get_notBefore}{}
296Return a string giving the time before which the certificate is not valid. The
297string is formatted as an ASN1 GENERALIZEDTIME:
298\begin{verbatim}
299 YYYYMMDDhhmmssZ
300 YYYYMMDDhhmmss+hhmm
301 YYYYMMDDhhmmss-hhmm
302\end{verbatim}
Jean-Paul Calderonee0615b52008-03-09 21:44:46 -0400303If no value exists for this field, \code{None} is returned.
Jean-Paul Calderone525ef802008-03-09 20:39:42 -0400304\end{methoddesc}
305
306\begin{methoddesc}[X509]{get_notAfter}{}
307Return a string giving the time after which the certificate is not valid. The
308string is formatted as an ASN1 GENERALIZEDTIME:
309\begin{verbatim}
310 YYYYMMDDhhmmssZ
311 YYYYMMDDhhmmss+hhmm
312 YYYYMMDDhhmmss-hhmm
313\end{verbatim}
Jean-Paul Calderonee0615b52008-03-09 21:44:46 -0400314If no value exists for this field, \code{None} is returned.
Jean-Paul Calderone525ef802008-03-09 20:39:42 -0400315\end{methoddesc}
316
317\begin{methoddesc}[X509]{set_notBefore}{when}
318Change the time before which the certificate is not valid. \var{when} is a
319string formatted as an ASN1 GENERALIZEDTIME:
320\begin{verbatim}
321 YYYYMMDDhhmmssZ
322 YYYYMMDDhhmmss+hhmm
323 YYYYMMDDhhmmss-hhmm
324\end{verbatim}
325\end{methoddesc}
326
327\begin{methoddesc}[X509]{set_notAfter}{when}
328Change the time after which the certificate is not valid. \var{when} is a
329string formatted as an ASN1 GENERALIZEDTIME:
330\begin{verbatim}
331 YYYYMMDDhhmmssZ
332 YYYYMMDDhhmmss+hhmm
333 YYYYMMDDhhmmss-hhmm
334\end{verbatim}
335\end{methoddesc}
336
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500337\begin{methoddesc}[X509]{gmtime_adj_notBefore}{time}
338Adjust the timestamp (in GMT) when the certificate starts being valid.
339\end{methoddesc}
340
341\begin{methoddesc}[X509]{gmtime_adj_notAfter}{time}
342Adjust the timestamp (in GMT) when the certificate stops being valid.
343\end{methoddesc}
344
345\begin{methoddesc}[X509]{has_expired}{}
346Checks the certificate's time stamp against current time. Returns true if the
347certificate has expired and false otherwise.
348\end{methoddesc}
349
350\begin{methoddesc}[X509]{set_issuer}{issuer}
351Set the issuer of the certificate to \var{issuer}.
352\end{methoddesc}
353
354\begin{methoddesc}[X509]{set_pubkey}{pkey}
355Set the public key of the certificate to \var{pkey}.
356\end{methoddesc}
357
358\begin{methoddesc}[X509]{set_serial_number}{serialno}
359Set the serial number of the certificate to \var{serialno}.
360\end{methoddesc}
361
362\begin{methoddesc}[X509]{set_subject}{subject}
363Set the subject of the certificate to \var{subject}.
364\end{methoddesc}
365
366\begin{methoddesc}[X509]{set_version}{version}
367Set the certificate version to \var{version}.
368\end{methoddesc}
369
370\begin{methoddesc}[X509]{sign}{pkey, digest}
371Sign the certificate, using the key \var{pkey} and the message digest algorithm
372identified by the string \var{digest}.
373\end{methoddesc}
374
375\begin{methoddesc}[X509]{subject_name_hash}{}
376Return the hash of the certificate subject.
377\end{methoddesc}
378
379\begin{methoddesc}[X509]{digest}{digest_name}
380Return a digest of the certificate, using the \var{digest_name} method.
Jean-Paul Calderoneb6f0d602008-12-28 21:20:01 -0500381\var{digest_name} must be a string describing a digest algorithm supported
382by OpenSSL (by EVP_get_digestbyname, specifically). For example,
383\constant{"md5"} or \constant{"sha1"}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500384\end{methoddesc}
385
386\begin{methoddesc}[X509]{add_extensions}{extensions}
387Add the extensions in the sequence \var{extensions} to the certificate.
388\end{methoddesc}
389
390\subsubsection{X509Name objects \label{openssl-x509name}}
391
Jean-Paul Calderone2dd8ff52008-03-24 17:43:58 -0400392X509Name objects have the following methods:
393
394\begin{methoddesc}[X509Name]{hash}{}
395Return an integer giving the first four bytes of the MD5 digest of the DER
396representation of the name.
397\end{methoddesc}
398
Jean-Paul Calderonea6edbf82008-03-25 15:19:11 -0400399\begin{methoddesc}[X509Name]{der}{}
400Return a string giving the DER representation of the name.
401\end{methoddesc}
402
Jean-Paul Calderonec54cc182008-03-26 21:11:07 -0400403\begin{methoddesc}[X509Name]{get_components}{}
404Return a list of two-tuples of strings giving the components of the name.
405\end{methoddesc}
406
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500407X509Name objects have the following members:
408
409\begin{memberdesc}[X509Name]{countryName}
410The country of the entity. \code{C} may be used as an alias for
411\code{countryName}.
412\end{memberdesc}
413
414\begin{memberdesc}[X509Name]{stateOrProvinceName}
415The state or province of the entity. \code{ST} may be used as an alias for
416\code{stateOrProvinceName}·
417\end{memberdesc}
418
419\begin{memberdesc}[X509Name]{localityName}
420The locality of the entity. \code{L} may be used as an alias for
421\code{localityName}.
422\end{memberdesc}
423
424\begin{memberdesc}[X509Name]{organizationName}
425The organization name of the entity. \code{O} may be used as an alias for
426\code{organizationName}.
427\end{memberdesc}
428
429\begin{memberdesc}[X509Name]{organizationalUnitName}
430The organizational unit of the entity. \code{OU} may be used as an alias for
431\code{organizationalUnitName}.
432\end{memberdesc}
433
434\begin{memberdesc}[X509Name]{commonName}
435The common name of the entity. \code{CN} may be used as an alias for
436\code{commonName}.
437\end{memberdesc}
438
439\begin{memberdesc}[X509Name]{emailAddress}
440The e-mail address of the entity.
441\end{memberdesc}
442
443\subsubsection{X509Req objects \label{openssl-x509req}}
444
445X509Req objects have the following methods:
446
447\begin{methoddesc}[X509Req]{get_pubkey}{}
448Return a PKey object representing the public key of the certificate request.
449\end{methoddesc}
450
451\begin{methoddesc}[X509Req]{get_subject}{}
Jean-Paul Calderone2aa2b332008-03-06 21:43:14 -0500452Return an X509Name object representing the subject of the certificate.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500453\end{methoddesc}
454
455\begin{methoddesc}[X509Req]{set_pubkey}{pkey}
456Set the public key of the certificate request to \var{pkey}.
457\end{methoddesc}
458
459\begin{methoddesc}[X509Req]{sign}{pkey, digest}
460Sign the certificate request, using the key \var{pkey} and the message digest
461algorithm identified by the string \var{digest}.
462\end{methoddesc}
463
464\begin{methoddesc}[X509Req]{verify}{pkey}
465Verify a certificate request using the public key \var{pkey}.
466\end{methoddesc}
467
Jean-Paul Calderone8dd19b82008-12-28 20:41:16 -0500468\begin{methoddesc}[X509Req]{set_version}{version}
469Set the version (RFC 2459, 4.1.2.1) of the certificate request to
470\var{version}.
471\end{methoddesc}
472
473\begin{methoddesc}[X509Req]{get_version}{}
474Get the version (RFC 2459, 4.1.2.1) of the certificate request.
475\end{methoddesc}
476
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500477\subsubsection{X509Store objects \label{openssl-x509store}}
478
479The X509Store object has currently just one method:
480
481\begin{methoddesc}[X509Store]{add_cert}{cert}
482Add the certificate \var{cert} to the certificate store.
483\end{methoddesc}
484
485\subsubsection{PKey objects \label{openssl-pkey}}
486
487The PKey object has the following methods:
488
489\begin{methoddesc}[PKey]{bits}{}
490Return the number of bits of the key.
491\end{methoddesc}
492
493\begin{methoddesc}[PKey]{generate_key}{type, bits}
494Generate a public/private key pair of the type \var{type} (one of
495\constant{TYPE_RSA} and \constant{TYPE_DSA}) with the size \var{bits}.
496\end{methoddesc}
497
498\begin{methoddesc}[PKey]{type}{}
499Return the type of the key.
500\end{methoddesc}
501
502\subsubsection{PKCS7 objects \label{openssl-pkcs7}}
503
504PKCS7 objects have the following methods:
505
506\begin{methoddesc}[PKCS7]{type_is_signed}{}
507FIXME
508\end{methoddesc}
509
510\begin{methoddesc}[PKCS7]{type_is_enveloped}{}
511FIXME
512\end{methoddesc}
513
514\begin{methoddesc}[PKCS7]{type_is_signedAndEnveloped}{}
515FIXME
516\end{methoddesc}
517
518\begin{methoddesc}[PKCS7]{type_is_data}{}
519FIXME
520\end{methoddesc}
521
522\begin{methoddesc}[PKCS7]{get_type_name}{}
523Get the type name of the PKCS7.
524\end{methoddesc}
525
526\subsubsection{PKCS12 objects \label{openssl-pkcs12}}
527
528PKCS12 objects have the following methods:
529
Rick Dean42d69e12009-07-20 11:36:08 -0500530\begin{methoddesc}[PKCS12]{export}{\optional{passphrase=None}\optional{, iter=2048}\optional{, maciter=1}}
Rick Deane182f482009-07-17 14:49:48 -0500531Returns a PKCS12 object as a string.
532
533The optional \var{passphrase} must be a string not a callback.
534
535See also the man page for the C function \function{PKCS12_create}.
536\end{methoddesc}
537
538\begin{methoddesc}[PKCS12]{get_ca_certificates}{}
539Return CA certificates within the PKCS12 object as a tuple. Returns
540\constant{None} if no CA certificates are present.
541\end{methoddesc}
542
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500543\begin{methoddesc}[PKCS12]{get_certificate}{}
544Return certificate portion of the PKCS12 structure.
545\end{methoddesc}
546
Rick Dean42d69e12009-07-20 11:36:08 -0500547\begin{methoddesc}[PKCS12]{get_friendlyname}{}
548Return friendlyName portion of the PKCS12 structure.
549\end{methoddesc}
550
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500551\begin{methoddesc}[PKCS12]{get_privatekey}{}
552Return private key portion of the PKCS12 structure
553\end{methoddesc}
554
Rick Deane182f482009-07-17 14:49:48 -0500555\begin{methoddesc}[PKCS12]{set_ca_certificates}{cacerts}
556Replace or set the CA certificates within the PKCS12 object with the sequence \var{cacerts}.
557
558Set \var{cacerts} to \constant{None} to remove all CA certificates.
559\end{methoddesc}
560
561\begin{methoddesc}[PKCS12]{set_certificate}{cert}
562Replace or set the certificate portion of the PKCS12 structure.
563\end{methoddesc}
564
Rick Dean42d69e12009-07-20 11:36:08 -0500565\begin{methoddesc}[PKCS12]{set_friendlyname}{name}
566Replace or set the friendlyName portion of the PKCS12 structure.
567\end{methoddesc}
568
Rick Deane182f482009-07-17 14:49:48 -0500569\begin{methoddesc}[PKCS12]{set_privatekey}{pkey}
570Replace or set private key portion of the PKCS12 structure
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500571\end{methoddesc}
572
573\subsubsection{X509Extension objects \label{openssl-509ext}}
574
Jean-Paul Calderonef8c5fab2008-12-31 15:53:48 -0500575X509Extension objects have several methods:
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500576
577\begin{methoddesc}[X509Extension]{get_critical}{}
578Return the critical field of the extension object.
579\end{methoddesc}
580
Jean-Paul Calderonef8c5fab2008-12-31 15:53:48 -0500581\begin{methoddesc}[X509Extension]{get_short_name}{}
582Return the short type name of the extension object.
583\end{methoddesc}
584
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500585\subsubsection{NetscapeSPKI objects \label{openssl-netscape-spki}}
586
587NetscapeSPKI objects have the following methods:
588
589\begin{methoddesc}[NetscapeSPKI]{b64_encode}{}
590Return a base64-encoded string representation of the object.
591\end{methoddesc}
592
593\begin{methoddesc}[NetscapeSPKI]{get_pubkey}{}
594Return the public key of object.
595\end{methoddesc}
596
597\begin{methoddesc}[NetscapeSPKI]{set_pubkey}{key}
598Set the public key of the object to \var{key}.
599\end{methoddesc}
600
601\begin{methoddesc}[NetscapeSPKI]{sign}{key, digest_name}
Jean-Paul Calderoneb6f0d602008-12-28 21:20:01 -0500602Sign the NetscapeSPKI object using the given \var{key} and
603\var{digest_name}. \var{digest_name} must be a string describing a digest
604algorithm supported by OpenSSL (by EVP_get_digestbyname, specifically). For
605example, \constant{"md5"} or \constant{"sha1"}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500606\end{methoddesc}
607
608\begin{methoddesc}[NetscapeSPKI]{verify}{key}
609Verify the NetscapeSPKI object using the given \var{key}.
610\end{methoddesc}
611
612
613% % % rand module
614
615\subsection{\module{rand} --- An interface to the OpenSSL pseudo random number generator \label{openssl-rand}}
616
617\declaremodule{extension}{rand}
618\modulesynopsis{An interface to the OpenSSL pseudo random number generator}
619
620This module handles the OpenSSL pseudo random number generator (PRNG) and
621declares the following:
622
623\begin{funcdesc}{add}{string, entropy}
624Mix bytes from \var{string} into the PRNG state. The \var{entropy} argument is
625(the lower bound of) an estimate of how much randomness is contained in
626\var{string}, measured in bytes. For more information, see e.g. \rfc{1750}.
627\end{funcdesc}
628
Rick Dean4fd5a4e2009-07-08 12:06:10 -0500629\begin{funcdesc}{bytes}{num_bytes}
Jean-Paul Calderonea45e2b92009-07-08 13:29:58 -0400630Get some random bytes from the PRNG as a string.
631
632This is a wrapper for the C function \function{RAND_bytes}.
Rick Dean4fd5a4e2009-07-08 12:06:10 -0500633\end{funcdesc}
634
Rick Dean433dc642009-07-07 13:11:55 -0500635\begin{funcdesc}{cleanup}{}
Jean-Paul Calderone427c0b32009-07-07 15:43:27 -0400636Erase the memory used by the PRNG.
637
638This is a wrapper for the C function \function{RAND_cleanup}.
Rick Dean433dc642009-07-07 13:11:55 -0500639\end{funcdesc}
640
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500641\begin{funcdesc}{egd}{path\optional{, bytes}}
642Query the Entropy Gathering Daemon\footnote{See
643\url{http://www.lothar.com/tech/crypto/}} on socket \var{path} for \var{bytes}
644bytes of random data and and uses \function{add} to seed the PRNG. The default
645value of \var{bytes} is 255.
646\end{funcdesc}
647
648\begin{funcdesc}{load_file}{path\optional{, bytes}}
649Read \var{bytes} bytes (or all of it, if \var{bytes} is negative) of data from
650the file \var{path} to seed the PRNG. The default value of \var{bytes} is -1.
651\end{funcdesc}
652
653\begin{funcdesc}{screen}{}
654Add the current contents of the screen to the PRNG state.
655Availability: Windows.
656\end{funcdesc}
657
658\begin{funcdesc}{seed}{string}
659This is equivalent to calling \function{add} with \var{entropy} as the length
660of the string.
661\end{funcdesc}
662
663\begin{funcdesc}{status}{}
664Returns true if the PRNG has been seeded with enough data, and false otherwise.
665\end{funcdesc}
666
667\begin{funcdesc}{write_file}{path}
668Write a number of random bytes (currently 1024) to the file \var{path}. This
669file can then be used with \function{load_file} to seed the PRNG again.
670\end{funcdesc}
671
Rick Deanfc69c812009-07-08 11:03:47 -0500672\begin{excdesc}{Error}
673If the current RAND method supports any errors, this is raised when needed.
674The default method does not raise this when the entropy pool is depleted.
675
676Whenever this exception is raised directly, it has a list of error messages
677from the OpenSSL error queue, where each item is a tuple \code{(\var{lib},
678\var{function}, \var{reason})}. Here \var{lib}, \var{function} and \var{reason}
679are all strings, describing where and what the problem is. See \manpage{err}{3}
680for more information.
681\end{excdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500682
683
684% % % SSL module
685
686\subsection{\module{SSL} --- An interface to the SSL-specific parts of OpenSSL \label{openssl-ssl}}
687
688\declaremodule{extension}{SSL}
689\modulesynopsis{An interface to the SSL-specific parts of OpenSSL}
690
691This module handles things specific to SSL. There are two objects defined:
692Context, Connection.
693
694\begin{datadesc}{SSLv2_METHOD}
695\dataline{SSLv3_METHOD}
696\dataline{SSLv23_METHOD}
697\dataline{TLSv1_METHOD}
698These constants represent the different SSL methods to use when creating a
699context object.
700\end{datadesc}
701
702\begin{datadesc}{VERIFY_NONE}
703\dataline{VERIFY_PEER}
704\dataline{VERIFY_FAIL_IF_NO_PEER_CERT}
705These constants represent the verification mode used by the Context
706object's \method{set_verify} method.
707\end{datadesc}
708
709\begin{datadesc}{FILETYPE_PEM}
710\dataline{FILETYPE_ASN1}
711File type constants used with the \method{use_certificate_file} and
712\method{use_privatekey_file} methods of Context objects.
713\end{datadesc}
714
715\begin{datadesc}{OP_SINGLE_DH_USE}
716\dataline{OP_EPHEMERAL_RSA}
717\dataline{OP_NO_SSLv2}
718\dataline{OP_NO_SSLv3}
719\dataline{OP_NO_TLSv1}
720Constants used with \method{set_options} of Context objects.
721\constant{OP_SINGLE_DH_USE} means to always create a new key when using ephemeral
722Diffie-Hellman. \constant{OP_EPHEMERAL_RSA} means to always use ephemeral RSA keys
723when doing RSA operations. \constant{OP_NO_SSLv2}, \constant{OP_NO_SSLv3} and
724\constant{OP_NO_TLSv1} means to disable those specific protocols. This is
725interesting if you're using e.g. \constant{SSLv23_METHOD} to get an SSLv2-compatible
726handshake, but don't want to use SSLv2.
727\end{datadesc}
728
729\begin{datadesc}{ContextType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400730See \class{Context}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500731\end{datadesc}
732
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400733\begin{classdesc}{Context}{method}
734A class representing SSL contexts. Contexts define the parameters of one or
735more SSL connections.
736
737\var{method} should be \constant{SSLv2_METHOD}, \constant{SSLv3_METHOD},
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500738\constant{SSLv23_METHOD} or \constant{TLSv1_METHOD}.
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400739\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500740
741\begin{datadesc}{ConnectionType}
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400742See \class{Connection}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500743\end{datadesc}
744
Jean-Paul Calderonefc4abd02009-07-04 16:15:36 -0400745\begin{classdesc}{Connection}{context, socket}
746A class representing SSL connections.
747
748\var{context} should be an instance of \class{Context} and \var{socket}
749should be a socket \footnote{Actually, all that is required is an object
750that \emph{behaves} like a socket, you could even use files, even though
751it'd be tricky to get the handshakes right!} object. \var{socket} may be
752\var{None}; in this case, the Connection is created with a memory BIO: see
753the \method{bio_read}, \method{bio_write}, and \method{bio_shutdown}
754methods.
755\end{classdesc}
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500756
757\begin{excdesc}{Error}
758This exception is used as a base class for the other SSL-related
759exceptions, but may also be raised directly.
760
761Whenever this exception is raised directly, it has a list of error messages
762from the OpenSSL error queue, where each item is a tuple \code{(\var{lib},
763\var{function}, \var{reason})}. Here \var{lib}, \var{function} and \var{reason}
764are all strings, describing where and what the problem is. See \manpage{err}{3}
765for more information.
766\end{excdesc}
767
768\begin{excdesc}{ZeroReturnError}
769This exception matches the error return code \code{SSL_ERROR_ZERO_RETURN}, and
770is raised when the SSL Connection has been closed. In SSL 3.0 and TLS 1.0, this
771only occurs if a closure alert has occurred in the protocol, i.e. the
772connection has been closed cleanly. Note that this does not necessarily
773mean that the transport layer (e.g. a socket) has been closed.
774
775It may seem a little strange that this is an exception, but it does match an
776\code{SSL_ERROR} code, and is very convenient.
777\end{excdesc}
778
779\begin{excdesc}{WantReadError}
780The operation did not complete; the same I/O method should be called again
781later, with the same arguments. Any I/O method can lead to this since new
782handshakes can occur at any time.
Rick Dean71fa0962009-07-09 23:56:39 -0500783
Jean-Paul Calderonecc787d52009-07-16 12:08:41 -0400784The wanted read is for \emph{dirty} data sent over the network, not the
785\emph{clean} data inside the tunnel. For a socket based SSL connection,
786\emph{read} means data coming at us over the network. Until that read
787succeeds, the attempted \method{OpenSSL.SSL.Connection.recv},
Rick Dean71fa0962009-07-09 23:56:39 -0500788\method{OpenSSL.SSL.Connection.send}, or
Jean-Paul Calderonecc787d52009-07-16 12:08:41 -0400789\method{OpenSSL.SSL.Connection.do_handshake} is prevented or incomplete. You
790probably want to \method{select()} on the socket before trying again.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500791\end{excdesc}
792
793\begin{excdesc}{WantWriteError}
Jean-Paul Calderonecc787d52009-07-16 12:08:41 -0400794See \exception{WantReadError}. The socket send buffer may be too full to
Rick Dean71fa0962009-07-09 23:56:39 -0500795write more data.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500796\end{excdesc}
797
798\begin{excdesc}{WantX509LookupError}
799The operation did not complete because an application callback has asked to be
800called again. The I/O method should be called again later, with the same
801arguments. Note: This won't occur in this version, as there are no such
802callbacks in this version.
803\end{excdesc}
804
805\begin{excdesc}{SysCallError}
806The \exception{SysCallError} occurs when there's an I/O error and OpenSSL's
807error queue does not contain any information. This can mean two things: An
808error in the transport protocol, or an end of file that violates the protocol.
809The parameter to the exception is always a pair \code{(\var{errnum},
810\var{errstr})}.
811\end{excdesc}
812
813
814\subsubsection{Context objects \label{openssl-context}}
815
816Context objects have the following methods:
817
818\begin{methoddesc}[Context]{check_privatekey}{}
819Check if the private key (loaded with \method{use_privatekey\optional{_file}})
820matches the certificate (loaded with \method{use_certificate\optional{_file}}).
Jean-Paul Calderonef05fbbe2008-03-06 21:52:35 -0500821Returns \code{None} if they match, raises \exception{Error} otherwise.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500822\end{methoddesc}
823
824\begin{methoddesc}[Context]{get_app_data}{}
825Retrieve application data as set by \method{set_app_data}.
826\end{methoddesc}
827
828\begin{methoddesc}[Context]{get_cert_store}{}
829Retrieve the certificate store (a X509Store object) that the context uses.
830This can be used to add "trusted" certificates without using the.
831\method{load_verify_locations()} method.
832\end{methoddesc}
833
834\begin{methoddesc}[Context]{get_timeout}{}
835Retrieve session timeout, as set by \method{set_timeout}. The default is 300
836seconds.
837\end{methoddesc}
838
839\begin{methoddesc}[Context]{get_verify_depth}{}
840Retrieve the Context object's verify depth, as set by
841\method{set_verify_depth}.
842\end{methoddesc}
843
844\begin{methoddesc}[Context]{get_verify_mode}{}
Jean-Paul Calderoneae4238d2008-12-28 21:13:50 -0500845Retrieve the Context object's verify mode, as set by \method{set_verify}.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500846\end{methoddesc}
847
848\begin{methoddesc}[Context]{load_client_ca}{pemfile}
849Read a file with PEM-formatted certificates that will be sent to the client
850when requesting a client certificate.
851\end{methoddesc}
852
Jean-Paul Calderone5601c242008-09-07 21:06:52 -0400853\begin{methoddesc}[Context]{load_verify_locations}{pemfile, capath}
854Specify where CA certificates for verification purposes are located. These
855are trusted certificates. Note that the certificates have to be in PEM
856format. If capath is passed, it must be a directory prepared using the
857\code{c_rehash} tool included with OpenSSL. Either, but not both, of
858\var{pemfile} or \var{capath} may be \code{None}.
859\end{methoddesc}
860
861\begin{methoddesc}[Context]{set_default_verify_paths}{}
862Specify that the platform provided CA certificates are to be used for
Jean-Paul Calderone1d287e52009-03-07 09:09:07 -0500863verification purposes. This method may not work properly on OS X.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500864\end{methoddesc}
865
866\begin{methoddesc}[Context]{load_tmp_dh}{dhfile}
867Load parameters for Ephemeral Diffie-Hellman from \var{dhfile}.
868\end{methoddesc}
869
870\begin{methoddesc}[Context]{set_app_data}{data}
871Associate \var{data} with this Context object. \var{data} can be retrieved
872later using the \method{get_app_data} method.
873\end{methoddesc}
874
875\begin{methoddesc}[Context]{set_cipher_list}{ciphers}
876Set the list of ciphers to be used in this context. See the OpenSSL manual for
877more information (e.g. ciphers(1))
878\end{methoddesc}
879
880\begin{methoddesc}[Context]{set_info_callback}{callback}
881Set the information callback to \var{callback}. This function will be called
882from time to time during SSL handshakes.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500883\var{callback} should take three arguments: a Connection object and two
884integers. The first integer specifies where in the SSL handshake the function
885was called, and the other the return code from a (possibly failed) internal
886function call.
887\end{methoddesc}
888
889\begin{methoddesc}[Context]{set_options}{options}
890Add SSL options. Options you have set before are not cleared!
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500891This method should be used with the \constant{OP_*} constants.
892\end{methoddesc}
893
894\begin{methoddesc}[Context]{set_passwd_cb}{callback\optional{, userdata}}
895Set the passphrase callback to \var{callback}. This function will be called
Jean-Paul Calderone1eeb29e2008-10-19 11:50:53 -0400896when a private key with a passphrase is loaded. \var{callback} must accept
897three positional arguments. First, an integer giving the maximum length of
898the passphrase it may return. If the returned passphrase is longer than
899this, it will be truncated. Second, a boolean value which will be true if
900the user should be prompted for the passphrase twice and the callback should
901verify that the two values supplied are equal. Third, the value given as the
902\var{userdata} parameter to \method{set_passwd_cb}. If an error occurs,
903\var{callback} should return a false value (e.g. an empty string).
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500904\end{methoddesc}
905
906\begin{methoddesc}[Context]{set_session_id}{name}
907Set the context \var{name} within which a session can be reused for this
908Context object. This is needed when doing session resumption, because there is
909no way for a stored session to know which Context object it is associated with.
910\var{name} may be any binary data.
911\end{methoddesc}
912
913\begin{methoddesc}[Context]{set_timeout}{timeout}
914Set the timeout for newly created sessions for this Context object to
915\var{timeout}. \var{timeout} must be given in (whole) seconds. The default
916value is 300 seconds. See the OpenSSL manual for more information (e.g.
917SSL_CTX_set_timeout(3)).
918\end{methoddesc}
919
920\begin{methoddesc}[Context]{set_verify}{mode, callback}
921Set the verification flags for this Context object to \var{mode} and specify
922that \var{callback} should be used for verification callbacks. \var{mode}
923should be one of \constant{VERIFY_NONE} and \constant{VERIFY_PEER}. If
924\constant{VERIFY_PEER} is used, \var{mode} can be OR:ed with
925\constant{VERIFY_FAIL_IF_NO_PEER_CERT} and \constant{VERIFY_CLIENT_ONCE} to
926further control the behaviour.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500927\var{callback} should take five arguments: A Connection object, an X509 object,
928and three integer variables, which are in turn potential error number, error
929depth and return code. \var{callback} should return true if verification passes
930and false otherwise.
931\end{methoddesc}
932
933\begin{methoddesc}[Context]{set_verify_depth}{depth}
934Set the maximum depth for the certificate chain verification that shall be
935allowed for this Context object.
936\end{methoddesc}
937
938\begin{methoddesc}[Context]{use_certificate}{cert}
939Use the certificate \var{cert} which has to be a X509 object.
940\end{methoddesc}
941
Jean-Paul Calderone87b40602008-02-19 21:13:25 -0500942\begin{methoddesc}[Context]{add_extra_chain_cert}{cert}
943Adds the certificate \var{cert}, which has to be a X509 object, to the
944certificate chain presented together with the certificate.
945\end{methoddesc}
946
Jean-Paul Calderone897bc252008-02-18 20:50:23 -0500947\begin{methoddesc}[Context]{use_certificate_chain_file}{file}
948Load a certificate chain from \var{file} which must be PEM encoded.
949\end{methoddesc}
950
951\begin{methoddesc}[Context]{use_privatekey}{pkey}
952Use the private key \var{pkey} which has to be a PKey object.
953\end{methoddesc}
954
955\begin{methoddesc}[Context]{use_certificate_file}{file\optional{, format}}
956Load the first certificate found in \var{file}. The certificate must be in the
957format specified by \var{format}, which is either \constant{FILETYPE_PEM} or
958\constant{FILETYPE_ASN1}. The default is \constant{FILETYPE_PEM}.
959\end{methoddesc}
960
961\begin{methoddesc}[Context]{use_privatekey_file}{file\optional{, format}}
962Load the first private key found in \var{file}. The private key must be in the
963format specified by \var{format}, which is either \constant{FILETYPE_PEM} or
964\constant{FILETYPE_ASN1}. The default is \constant{FILETYPE_PEM}.
965\end{methoddesc}
966
967
968\subsubsection{Connection objects \label{openssl-connection}}
969
970Connection objects have the following methods:
971
972\begin{methoddesc}[Connection]{accept}{}
973Call the \method{accept} method of the underlying socket and set up SSL on the
974returned socket, using the Context object supplied to this Connection object at
975creation. Returns a pair \code{(\var{conn}, \var{address})}. where \var{conn}
976is the new Connection object created, and \var{address} is as returned by the
977socket's \method{accept}.
978\end{methoddesc}
979
980\begin{methoddesc}[Connection]{bind}{address}
981Call the \method{bind} method of the underlying socket.
982\end{methoddesc}
983
984\begin{methoddesc}[Connection]{close}{}
985Call the \method{close} method of the underlying socket. Note: If you want
986correct SSL closure, you need to call the \method{shutdown} method first.
987\end{methoddesc}
988
989\begin{methoddesc}[Connection]{connect}{address}
990Call the \method{connect} method of the underlying socket and set up SSL on the
991socket, using the Context object supplied to this Connection object at
992creation.
993\end{methoddesc}
994
995\begin{methoddesc}[Connection]{connect_ex}{address}
996Call the \method{connect_ex} method of the underlying socket and set up SSL on
997the socket, using the Context object supplied to this Connection object at
998creation. Note that if the \method{connect_ex} method of the socket doesn't
999return 0, SSL won't be initialized.
1000\end{methoddesc}
1001
1002\begin{methoddesc}[Connection]{do_handshake}{}
1003Perform an SSL handshake (usually called after \method{renegotiate} or one of
1004\method{set_accept_state} or \method{set_accept_state}). This can raise the
1005same exceptions as \method{send} and \method{recv}.
1006\end{methoddesc}
1007
1008\begin{methoddesc}[Connection]{fileno}{}
1009Retrieve the file descriptor number for the underlying socket.
1010\end{methoddesc}
1011
1012\begin{methoddesc}[Connection]{listen}{backlog}
1013Call the \method{listen} method of the underlying socket.
1014\end{methoddesc}
1015
1016\begin{methoddesc}[Connection]{get_app_data}{}
1017Retrieve application data as set by \method{set_app_data}.
1018\end{methoddesc}
1019
1020\begin{methoddesc}[Connection]{get_cipher_list}{}
1021Retrieve the list of ciphers used by the Connection object. WARNING: This API
1022has changed. It used to take an optional parameter and just return a string,
1023but not it returns the entire list in one go.
1024\end{methoddesc}
1025
1026\begin{methoddesc}[Connection]{get_context}{}
1027Retrieve the Context object associated with this Connection.
1028\end{methoddesc}
1029
1030\begin{methoddesc}[Connection]{get_peer_certificate}{}
1031Retrieve the other side's certificate (if any)
1032\end{methoddesc}
1033
1034\begin{methoddesc}[Connection]{getpeername}{}
1035Call the \method{getpeername} method of the underlying socket.
1036\end{methoddesc}
1037
1038\begin{methoddesc}[Connection]{getsockname}{}
1039Call the \method{getsockname} method of the underlying socket.
1040\end{methoddesc}
1041
1042\begin{methoddesc}[Connection]{getsockopt}{level, optname\optional{, buflen}}
1043Call the \method{getsockopt} method of the underlying socket.
1044\end{methoddesc}
1045
1046\begin{methoddesc}[Connection]{pending}{}
Jean-Paul Calderoneb6f57be2008-03-06 21:22:16 -05001047Retrieve the number of bytes that can be safely read from the SSL buffer
1048(\emph{not} the underlying transport buffer).
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001049\end{methoddesc}
1050
1051\begin{methoddesc}[Connection]{recv}{bufsize}
1052Receive data from the Connection. The return value is a string representing the
1053data received. The maximum amount of data to be received at once, is specified
1054by \var{bufsize}.
1055\end{methoddesc}
1056
Jean-Paul Calderoneb6b17122009-05-01 16:36:11 -04001057\begin{methoddesc}[Connection]{bio_write}{bytes}
1058If the Connection was created with a memory BIO, this method can be used to add
1059bytes to the read end of that memory BIO. The Connection can then read the
1060bytes (for example, in response to a call to \method{recv}).
1061\end{methoddesc}
1062
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001063\begin{methoddesc}[Connection]{renegotiate}{}
1064Renegotiate the SSL session. Call this if you wish to change cipher suites or
1065anything like that.
1066\end{methoddesc}
1067
1068\begin{methoddesc}[Connection]{send}{string}
1069Send the \var{string} data to the Connection.
1070\end{methoddesc}
1071
Jean-Paul Calderoneb6b17122009-05-01 16:36:11 -04001072\begin{methoddesc}[Connection]{bio_read}{bufsize}
1073If the Connection was created with a memory BIO, this method can be used to
1074read bytes from the write end of that memory BIO. Many Connection methods will
1075add bytes which must be read in this manner or the buffer will eventually fill
1076up and the Connection will be able to take no further actions.
1077\end{methoddesc}
1078
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001079\begin{methoddesc}[Connection]{sendall}{string}
1080Send all of the \var{string} data to the Connection. This calls \method{send}
1081repeatedly until all data is sent. If an error occurs, it's impossible to tell
1082how much data has been sent.
1083\end{methoddesc}
1084
1085\begin{methoddesc}[Connection]{set_accept_state}{}
1086Set the connection to work in server mode. The handshake will be handled
1087automatically by read/write.
1088\end{methoddesc}
1089
1090\begin{methoddesc}[Connection]{set_app_data}{data}
1091Associate \var{data} with this Connection object. \var{data} can be retrieved
1092later using the \method{get_app_data} method.
1093\end{methoddesc}
1094
1095\begin{methoddesc}[Connection]{set_connect_state}{}
1096Set the connection to work in client mode. The handshake will be handled
1097automatically by read/write.
1098\end{methoddesc}
1099
1100\begin{methoddesc}[Connection]{setblocking}{flag}
1101Call the \method{setblocking} method of the underlying socket.
1102\end{methoddesc}
1103
1104\begin{methoddesc}[Connection]{setsockopt}{level, optname, value}
1105Call the \method{setsockopt} method of the underlying socket.
1106\end{methoddesc}
1107
1108\begin{methoddesc}[Connection]{shutdown}{}
1109Send the shutdown message to the Connection. Returns true if the shutdown
1110message exchange is completed and false otherwise (in which case you call
1111\method{recv()} or \method{send()} when the connection becomes
1112readable/writeable.
1113\end{methoddesc}
1114
Jean-Paul Calderone72b8f0f2008-02-21 23:57:40 -05001115\begin{methoddesc}[Connection]{get_shutdown}{}
1116Get the shutdown state of the Connection. Returns a bitvector of either or
1117both of \var{SENT_SHUTDOWN} and \var{RECEIVED_SHUTDOWN}.
1118\end{methoddesc}
1119
1120\begin{methoddesc}[Connection]{set_shutdown}{state}
1121Set the shutdown state of the Connection. \var{state} is a bitvector of
1122either or both of \var{SENT_SHUTDOWN} and \var{RECEIVED_SHUTDOWN}.
1123\end{methoddesc}
1124
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001125\begin{methoddesc}[Connection]{sock_shutdown}{how}
1126Call the \method{shutdown} method of the underlying socket.
1127\end{methoddesc}
1128
Jean-Paul Calderoneb6b17122009-05-01 16:36:11 -04001129\begin{methoddesc}[Connection]{bio_shutdown}{}
1130If the Connection was created with a memory BIO, this method can be used to
1131indicate that ``end of file'' has been reached on the read end of that memory
1132BIO.
1133\end{methoddesc}
1134
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001135\begin{methoddesc}[Connection]{state_string}{}
1136Retrieve a verbose string detailing the state of the Connection.
1137\end{methoddesc}
1138
Jean-Paul Calderonefd236f32009-05-03 19:45:07 -04001139\begin{methoddesc}[Connection]{client_random}{}
1140Retrieve the random value used with the client hello message.
1141\end{methoddesc}
1142
1143\begin{methoddesc}[Connection]{server_random}{}
1144Retrieve the random value used with the server hello message.
1145\end{methoddesc}
1146
1147\begin{methoddesc}[Connection]{master_key}{}
1148Retrieve the value of the master key for this session.
1149\end{methoddesc}
1150
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001151\begin{methoddesc}[Connection]{want_read}{}
1152Checks if more data has to be read from the transport layer to complete an
1153operation.
1154\end{methoddesc}
1155
1156\begin{methoddesc}[Connection]{want_write}{}
1157Checks if there is data to write to the transport layer to complete an
1158operation.
1159\end{methoddesc}
1160
1161
1162
1163\section{Internals \label{internals}}
1164
1165We ran into three main problems developing this: Exceptions, callbacks and
1166accessing socket methods. This is what this chapter is about.
1167
1168\subsection{Exceptions \label{exceptions}}
1169
1170We realized early that most of the exceptions would be raised by the I/O
1171functions of OpenSSL, so it felt natural to mimic OpenSSL's error code system,
1172translating them into Python exceptions. This naturally gives us the exceptions
1173\exception{SSL.ZeroReturnError}, \exception{SSL.WantReadError},
1174\exception{SSL.WantWriteError}, \exception{SSL.WantX509LookupError} and
1175\exception{SSL.SysCallError}.
1176
1177For more information about this, see section \ref{openssl-ssl}.
1178
1179
1180\subsection{Callbacks \label{callbacks}}
1181
1182There are a number of problems with callbacks. First of all, OpenSSL is written
1183as a C library, it's not meant to have Python callbacks, so a way around that
1184is needed. Another problem is thread support. A lot of the OpenSSL I/O
1185functions can block if the socket is in blocking mode, and then you want other
1186Python threads to be able to do other things. The real trouble is if you've
Jean-Paul Calderoneb7d6db22008-09-21 18:57:56 -04001187released the global CPython interpreter lock to do a potentially blocking
1188operation, and the operation calls a callback. Then we must take the GIL back,
1189since calling Python APIs without holding it is not allowed.
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001190
1191There are two solutions to the first problem, both of which are necessary. The
1192first solution to use is if the C callback allows ''userdata'' to be passed to
1193it (an arbitrary pointer normally). This is great! We can set our Python
1194function object as the real userdata and emulate userdata for the Python
1195function in another way. The other solution can be used if an object with an
1196''app_data'' system always is passed to the callback. For example, the SSL
1197object in OpenSSL has app_data functions and in e.g. the verification
1198callbacks, you can retrieve the related SSL object. What we do is to set our
1199wrapper \class{Connection} object as app_data for the SSL object, and we can
1200easily find the Python callback.
1201
Jean-Paul Calderoneb7d6db22008-09-21 18:57:56 -04001202The other problem is solved using thread local variables. Whenever the GIL is
1203released before calling into an OpenSSL API, the PyThreadState pointer returned
1204by \cfunction{PyEval_SaveState} is stored in a global thread local variable
1205(using Python's own TLS API, \cfunction{PyThread_set_key_value}). When it is
1206necessary to re-acquire the GIL, either after the OpenSSL API returns or in a C
1207callback invoked by that OpenSSL API, the value of the thread local variable is
1208retrieved (\cfunction{PyThread_get_key_value}) and used to re-acquire the GIL.
1209This allows Python threads to execute while OpenSSL APIs are running and allows
1210use of any particular pyOpenSSL object from any Python thread, since there is
1211no per-thread state associated with any of these objects and since OpenSSL is
1212threadsafe (as long as properly initialized, as pyOpenSSL initializes it).
Jean-Paul Calderone897bc252008-02-18 20:50:23 -05001213
1214
1215\subsection{Acessing Socket Methods \label{socket-methods}}
1216
1217We quickly saw the benefit of wrapping socket methods in the
1218\class{SSL.Connection} class, for an easy transition into using SSL. The
1219problem here is that the \module{socket} module lacks a C API, and all the
1220methods are declared static. One approach would be to have \module{OpenSSL} as
1221a submodule to the \module{socket} module, placing all the code in
1222\file{socketmodule.c}, but this is obviously not a good solution, since you
1223might not want to import tonnes of extra stuff you're not going to use when
1224importing the \module{socket} module. The other approach is to somehow get a
1225pointer to the method to be called, either the C function, or a callable Python
1226object. This is not really a good solution either, since there's a lot of
1227lookups involved.
1228
1229The way it works is that you have to supply a ``\class{socket}-like'' transport
1230object to the \class{SSL.Connection}. The only requirement of this object is
1231that it has a \method{fileno()} method that returns a file descriptor that's
1232valid at the C level (i.e. you can use the system calls read and write). If you
1233want to use the \method{connect()} or \method{accept()} methods of the
1234\class{SSL.Connection} object, the transport object has to supply such
1235methods too. Apart from them, any method lookups in the \class{SSL.Connection}
1236object that fail are passed on to the underlying transport object.
1237
1238Future changes might be to allow Python-level transport objects, that instead
1239of having \method{fileno()} methods, have \method{read()} and \method{write()}
1240methods, so more advanced features of Python can be used. This would probably
1241entail some sort of OpenSSL ``BIOs'', but converting Python strings back and
1242forth is expensive, so this shouldn't be used unless necessary. Other nice
1243things would be to be able to pass in different transport objects for reading
1244and writing, but then the \method{fileno()} method of \class{SSL.Connection}
1245becomes virtually useless. Also, should the method resolution be used on the
1246read-transport or the write-transport?
1247
1248
1249\end{document}