1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
|
<?xml version="1.0" encoding="utf-8" ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="generator" content="Docutils 0.15b.dev: http://docutils.sourceforge.net/" />
<meta name="version" content="S5 1.1" />
<title>Wounded hero revived</title>
<style type="text/css">
/*
:Author: David Goodger (goodger@python.org)
:Id: $Id$
:Copyright: This stylesheet has been placed in the public domain.
Default cascading style sheet for the HTML output of Docutils.
See http://docutils.sf.net/docs/howto/html-stylesheets.html for how to
customize this style sheet.
*/
/* used to remove borders from tables and images */
.borderless, table.borderless td, table.borderless th {
border: 0 }
table.borderless td, table.borderless th {
/* Override padding for "table.docutils td" with "! important".
The right padding separates the table cells. */
padding: 0 0.5em 0 0 ! important }
.first {
/* Override more specific margin styles with "! important". */
margin-top: 0 ! important }
.last, .with-subtitle {
margin-bottom: 0 ! important }
.hidden {
display: none }
.subscript {
vertical-align: sub;
font-size: smaller }
.superscript {
vertical-align: super;
font-size: smaller }
a.toc-backref {
text-decoration: none ;
color: black }
blockquote.epigraph {
margin: 2em 5em ; }
dl.docutils dd {
margin-bottom: 0.5em }
object[type="image/svg+xml"], object[type="application/x-shockwave-flash"] {
overflow: hidden;
}
/* Uncomment (and remove this text!) to get bold-faced definition list terms
dl.docutils dt {
font-weight: bold }
*/
div.abstract {
margin: 2em 5em }
div.abstract p.topic-title {
font-weight: bold ;
text-align: center }
div.admonition, div.attention, div.caution, div.danger, div.error,
div.hint, div.important, div.note, div.tip, div.warning {
margin: 2em ;
border: medium outset ;
padding: 1em }
div.admonition p.admonition-title, div.hint p.admonition-title,
div.important p.admonition-title, div.note p.admonition-title,
div.tip p.admonition-title {
font-weight: bold ;
font-family: sans-serif }
div.attention p.admonition-title, div.caution p.admonition-title,
div.danger p.admonition-title, div.error p.admonition-title,
div.warning p.admonition-title, .code .error {
color: red ;
font-weight: bold ;
font-family: sans-serif }
/* Uncomment (and remove this text!) to get reduced vertical space in
compound paragraphs.
div.compound .compound-first, div.compound .compound-middle {
margin-bottom: 0.5em }
div.compound .compound-last, div.compound .compound-middle {
margin-top: 0.5em }
*/
div.dedication {
margin: 2em 5em ;
text-align: center ;
font-style: italic }
div.dedication p.topic-title {
font-weight: bold ;
font-style: normal }
div.figure {
margin-left: 2em ;
margin-right: 2em }
div.footer, div.header {
clear: both;
font-size: smaller }
div.line-block {
display: block ;
margin-top: 1em ;
margin-bottom: 1em }
div.line-block div.line-block {
margin-top: 0 ;
margin-bottom: 0 ;
margin-left: 1.5em }
div.sidebar {
margin: 0 0 0.5em 1em ;
border: medium outset ;
padding: 1em ;
background-color: #ffffee ;
width: 40% ;
float: right ;
clear: right }
div.sidebar p.rubric {
font-family: sans-serif ;
font-size: medium }
div.system-messages {
margin: 5em }
div.system-messages h1 {
color: red }
div.system-message {
border: medium outset ;
padding: 1em }
div.system-message p.system-message-title {
color: red ;
font-weight: bold }
div.topic {
margin: 2em }
h1.section-subtitle, h2.section-subtitle, h3.section-subtitle,
h4.section-subtitle, h5.section-subtitle, h6.section-subtitle {
margin-top: 0.4em }
h1.title {
text-align: center }
h2.subtitle {
text-align: center }
hr.docutils {
width: 75% }
img.align-left, .figure.align-left, object.align-left, table.align-left {
clear: left ;
float: left ;
margin-right: 1em }
img.align-right, .figure.align-right, object.align-right, table.align-right {
clear: right ;
float: right ;
margin-left: 1em }
img.align-center, .figure.align-center, object.align-center {
display: block;
margin-left: auto;
margin-right: auto;
}
table.align-center {
margin-left: auto;
margin-right: auto;
}
.align-left {
text-align: left }
.align-center {
clear: both ;
text-align: center }
.align-right {
text-align: right }
/* reset inner alignment in figures */
div.align-right {
text-align: inherit }
/* div.align-center * { */
/* text-align: left } */
.align-top {
vertical-align: top }
.align-middle {
vertical-align: middle }
.align-bottom {
vertical-align: bottom }
ol.simple, ul.simple {
margin-bottom: 1em }
ol.arabic {
list-style: decimal }
ol.loweralpha {
list-style: lower-alpha }
ol.upperalpha {
list-style: upper-alpha }
ol.lowerroman {
list-style: lower-roman }
ol.upperroman {
list-style: upper-roman }
p.attribution {
text-align: right ;
margin-left: 50% }
p.caption {
font-style: italic }
p.credits {
font-style: italic ;
font-size: smaller }
p.label {
white-space: nowrap }
p.rubric {
font-weight: bold ;
font-size: larger ;
color: maroon ;
text-align: center }
p.sidebar-title {
font-family: sans-serif ;
font-weight: bold ;
font-size: larger }
p.sidebar-subtitle {
font-family: sans-serif ;
font-weight: bold }
p.topic-title {
font-weight: bold }
pre.address {
margin-bottom: 0 ;
margin-top: 0 ;
font: inherit }
pre.literal-block, pre.doctest-block, pre.math, pre.code {
margin-left: 2em ;
margin-right: 2em }
pre.code .ln { color: grey; } /* line numbers */
pre.code, code { background-color: #eeeeee }
pre.code .comment, code .comment { color: #5C6576 }
pre.code .keyword, code .keyword { color: #3B0D06; font-weight: bold }
pre.code .literal.string, code .literal.string { color: #0C5404 }
pre.code .name.builtin, code .name.builtin { color: #352B84 }
pre.code .deleted, code .deleted { background-color: #DEB0A1}
pre.code .inserted, code .inserted { background-color: #A3D289}
span.classifier {
font-family: sans-serif ;
font-style: oblique }
span.classifier-delimiter {
font-family: sans-serif ;
font-weight: bold }
span.interpreted {
font-family: sans-serif }
span.option {
white-space: nowrap }
span.pre {
white-space: pre }
span.problematic {
color: red }
span.section-subtitle {
/* font-size relative to parent (h1..h6 element) */
font-size: 80% }
table.citation {
border-left: solid 1px gray;
margin-left: 1px }
table.docinfo {
margin: 2em 4em }
table.docutils {
margin-top: 0.5em ;
margin-bottom: 0.5em }
table.footnote {
border-left: solid 1px black;
margin-left: 1px }
table.docutils td, table.docutils th,
table.docinfo td, table.docinfo th {
padding-left: 0.5em ;
padding-right: 0.5em ;
vertical-align: top }
table.docutils th.field-name, table.docinfo th.docinfo-name {
font-weight: bold ;
text-align: left ;
white-space: nowrap ;
padding-left: 0 }
/* "booktabs" style (no vertical lines) */
table.docutils.booktabs {
border: 0px;
border-top: 2px solid;
border-bottom: 2px solid;
border-collapse: collapse;
}
table.docutils.booktabs * {
border: 0px;
}
table.docutils.booktabs th {
border-bottom: thin solid;
text-align: left;
}
h1 tt.docutils, h2 tt.docutils, h3 tt.docutils,
h4 tt.docutils, h5 tt.docutils, h6 tt.docutils {
font-size: 100% }
ul.auto-toc {
list-style-type: none }
</style>
<!-- configuration parameters -->
<meta name="defaultView" content="slideshow" />
<meta name="controlVis" content="hidden" />
<!-- style sheet links -->
<script src="ui/small-black/slides.js" type="text/javascript"></script>
<link rel="stylesheet" href="ui/small-black/slides.css"
type="text/css" media="projection" id="slideProj" />
<link rel="stylesheet" href="ui/small-black/outline.css"
type="text/css" media="screen" id="outlineStyle" />
<link rel="stylesheet" href="ui/small-black/print.css"
type="text/css" media="print" id="slidePrint" />
<link rel="stylesheet" href="ui/small-black/opera.css"
type="text/css" media="projection" id="operaFix" />
</head>
<body>
<div class="layout">
<div id="controls"></div>
<div id="currentSlide"></div>
<div id="header">
</div>
<div id="footer">
<h1>Wounded hero revived</h1>
</div>
</div>
<div class="presentation">
<div class="slide" id="slide0">
<h1 class="title">Wounded hero revived</h1>
<p>Lessons learned from porting M2Crypto to Py3k</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">Author:</th><td class="field-body">Matěj Cepl <<a class="reference external" href="mailto:mcepl%40cepl.eu">mcepl<span>@</span>cepl<span>.</span>eu</a>></td>
</tr>
</tbody>
</table>
</div>
<div class="slide" id="origins">
<h1>Origins</h1>
<ul class="simple">
<li>Mitch Kapor sold Lotus to IBM and decided to perpetrate good.
One of his projects was <a class="reference external" href="https://en.wikipedia.org/wiki/Chandler_(software)">Chandler</a>.</li>
<li>Project is <a class="reference external" href="https://gitlab.com/mcepl/chandler">gone</a> The only remainder of the project is
<a class="reference external" href="https://gitlab.com/m2crypto/m2crypto/">M2Crypto</a>, full Python binding for OpenSSL.</li>
</ul>
<p class="handout">Once upon a time, one Mitch Kapor, who sold Lotus to IBM, and
with money he got decided to perpetrate good. He did many
truly good things for the computer world, was co-founder of
EFF, helped with Mozilla Foundation, but he also founded
rather unsuccessful project, a Python-based universal PIM,
called <a class="reference external" href="https://en.wikipedia.org/wiki/Chandler_(software)">Chandler</a>.</p>
<p class="handout">Subversion of the project has been mirrored couple of times,
one by me.</p>
</div>
<div class="slide" id="id1">
<h1>M2Crypto</h1>
<ul class="simple">
<li>M2Crypto was maintained by <a class="reference external" href="https://www.heikkitoivonen.net/">Heikki Toivonen</a> few years after
Chandler folded, but his last release 0.21.1 was from 2011.</li>
<li>Maintenaned in Red Hat by <a class="reference external" href="https://github.com/mtrmac">Miloslav Trmač</a>.</li>
<li>I took over the project in May 2015.</li>
</ul>
<p class="handout">Maintenaned in Red Hat by <a class="reference external" href="https://github.com/mtrmac">Miloslav Trmač</a>, who collected
all patches in RHEL package.</p>
<p class="handout">I took over the project in May 2015 with the intention just
to publish all patches and be a point of contact for any
issue reports. I haven’t expected much activity, because
package was very silent in RHEL.</p>
</div>
<div class="slide" id="strengths-and-weaknesses">
<h1>Strengths and weaknesses</h1>
<!-- Strengths -->
<ul class="simple">
<li>Backed up by stable C library</li>
<li>Rather large coverage of OpenSSL API</li>
<li>Surprisingly widespread use</li>
<li>Large test suite</li>
</ul>
<!-- Weakness -->
<ul class="simple">
<li>Unknown issues</li>
<li>Python 3</li>
<li>M2Crypto API copies OpenSSL too closely</li>
<li>Support for Mac OS X and Windows (not mentioning <tt class="docutils literal">*BSD</tt>) was
broken.</li>
</ul>
<p class="handout">Backed by … comparing to PyCrypto and other horrors.</p>
</div>
<div class="slide" id="opportunities-threats">
<h1>Opportunities & Threats</h1>
<!-- Opportunities -->
<ul class="simple">
<li>Satisfying current user base</li>
<li>Replacing horrors like PyCrypto</li>
<li>Goal of maitenance is to maintain API</li>
<li>Extend support on non-Linux platforms</li>
</ul>
<!-- Threats -->
<ul class="simple">
<li>Python <tt class="docutils literal">ssl</tt> module</li>
<li>Python <a class="reference external" href="https://github.com/pyca/cryptography">cryptography</a></li>
</ul>
<p class="handout">Distribution bug tracker (especially an enterprise one) is
not a good measure of the real state of use and quality of
package.</p>
<p class="handout">There are apparently many programmers for custom software,
who use M2Crypto (still it is one of the most complete
bindings for OpenSSL).</p>
<p class="handout">Threats as a “competing” projects, which may replace
M2Crypto.</p>
</div>
<div class="slide" id="unicode">
<h1>Unicode</h1>
<ul class="simple">
<li>The biggest problem of all Python 2 programs: complete
confusion between py2k <tt class="docutils literal">str</tt> means py3k <tt class="docutils literal">str</tt> and when
<tt class="docutils literal">bytes</tt>.</li>
<li>There are numerous uses of both in M2Crypto, because of course
both strings and binary data are present in all functions of
OpenSSL.</li>
</ul>
</div>
<div class="slide" id="strategy">
<h1>Strategy</h1>
<ul class="simple">
<li>Type Hints</li>
<li>CI</li>
<li>Extension of platform support</li>
</ul>
</div>
<div class="slide" id="type-hints">
<h1>Type Hints</h1>
<ul>
<li><p class="first"><a class="reference external" href="https://www.python.org/dev/peps/pep-0484/">PEP 484</a> providing <strong>optional</strong> type annotations. Quite
controversial, but clearly very useful for libraries</p>
</li>
<li><p class="first">Native for Python >= 3.5, but supports py2k compatible syntax:</p>
<pre class="literal-block">
def sum(x, y):
# type: (int, int) -> int
return x + y
</pre>
</li>
<li><p class="first">Especially useful for our situation: marking types helps us to
analyze what invidivual py2k <tt class="docutils literal">str</tt> actually mean.</p>
</li>
</ul>
</div>
<div class="slide" id="c-api">
<h1>C API</h1>
<ul class="simple">
<li>All Unicode/bytes translation happens on C level as well</li>
<li>Based on <tt class="docutils literal">swig</tt>, which fortunately natively supports
<tt class="docutils literal"><span class="pre">--py3</span></tt>.</li>
<li>Also need to support two versions of OpenSSL API, 1.1 and
older.</li>
<li>Minimize use of <tt class="docutils literal">#ifdef</tt> s and rather use included shims
for missing functions.</li>
</ul>
</div>
<div class="slide" id="c-shims-of-missing-functions">
<h1>C shims of missing functions</h1>
<ul class="simple">
<li>For OpenSSL < 1.1</li>
<li>For Python 2<ul>
<li><tt class="docutils literal">PyLong_FromLong()</tt> and <tt class="docutils literal">PyUnicode_AsUTF8()</tt> just simple
<tt class="docutils literal">#define</tt> s.</li>
<li>All Pythons >= 2.6 contain whole set of Py3k function stubs
in <tt class="docutils literal">bytesobject.h</tt>.</li>
</ul>
</li>
<li>For Python 3<ul>
<li><tt class="docutils literal">PyFile_AsFile()</tt> I have no idea, why it was removed from
py3k API</li>
</ul>
</li>
</ul>
</div>
</div>
</body>
</html>
|
