Add scripts to generate simple test data for certificate verification.

net/data/verify_certificate_chain_unittest/openssl_conf.py

+#!/usr/bin/python
+# Copyright (c) 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+"""This file contains helpers for representing, manipulating, and writing
+OpenSSL configuration files [1]
+
+Configuration files are simply a collection of name=value "properties", which
+are grouped into "sections".
+
+[1] https://www.openssl.org/docs/manmaster/apps/config.html
+"""
+
+class Property(object):
+  """Represents a key/value pair in OpenSSL .cnf files.
+
+  Names and values are not quoted in any way, so callers need to pass the text
+  exactly as it should be written to the file (leading and trailing whitespace
+  doesn't matter).
+
+  For instance:
+      baseConstraints = critical, CA:false
+
+  Would be a property where:

[mattm, 2015/10/29 01:47:18]

I wasn't clear if this is just "property" in general or referring to the
Property class.
On my initial read it seemed that maybe should capitalize Property here, or even
just say:
Would be a Property('baseConstraints', 'critical, CA:false').
But maybe that was intentional.
(Similar comment for Section below.)

[eroman, 2015/10/31 00:34:25]

Done. Changed to:

 25   Could be represented by a Property where:
 26     name = 'baseConstraints'
 27     value = 'critical, CA:false'

And for Section I changed to:

 44   Could be represented by a Section where:
 45     name = 'CA_root'       
 46     properties = [Property('preserve', 'true')]

+    name = 'baseConstraints'
+    value='critical, CA:false'
+  """
+  def __init__(self, name, value):
+    self.name = name
+    self.value = value
+
+
+  def WriteTo(self, out):
+    """Outputs this property to .cnf file."""
+    out.write('%s = %s\n' % (self.name, self.value))
+
+
+class Section(object):
+  """Represents a section in OpenSSL. For instance:
+      [CA_root]
+      preserve = true
+
+  Is a section named 'CA_root' containing 1 property.
+  """
+  def __init__(self, name):
+    self.name = name
+    self.properties = []
+
+
+  def SetProperty(self, name, value):
+    """If value is None then the property is deleted. Otherwise overwrites or
+    adds it"""

[mattm, 2015/10/29 01:47:18]

Should define how this (and RemoveProperty) handle the case of duplicates.

[eroman, 2015/10/31 00:34:25]

Done, good point.

I have documented that duplicates are not allowed for SetProperties() and for
RemoveProperty(), and enforced it in the code (rather than doing something
arbitrary like changing the first property found):


 63   def SetProperty(self, name, value):
 64     """Replaces, adds, or removes a Property from the Section:
 65 
 66       - If |value| is None, then this is equivalent to calling
 67         RemoveProperty(name)
 68       - If there is an existing property matching |name| then its value is
 69         replaced with |value|
 70       - If there are no properties matching |name| then a new one is added
at
 71         the end of the section
 72       
 73     It is expected that there is AT MOST 1 property with the given name. If
 74     that is not the case then this function will raise an error."""

+    if value is None:
+      self.RemoveProperty(name)
+      return
+
+    for prop in self.properties:
+      if prop.name == name:
+        prop.value = value
+        return
+
+    self.AddProperty(name, value)
+
+
+  def AddProperty(self, name, value):
+    """Adds a property (allows duplicates)"""
+    self.properties.append(Property(name, value))
+
+
+  def RemoveProperty(self, name):
+    """Removes the property with the indicated name, if it exists."""
+    for i in range(len(self.properties)):
+      if self.properties[i].name == name:
+        self.properties.pop(i)
+        return
+
+
+  def WriteTo(self, out):
+    """Outputs the section in the format used by .cnf files"""
+    out.write('[%s]\n' % (self.name))
+    for prop in self.properties:
+      prop.WriteTo(out)
+    out.write('\n')
+
+
+class Config(object):
+  """Represents a .cnf (configuration) file in OpenSSL"""
+  def __init__(self):
+    self.sections = []
+
+
+  def GetSection(self, name):
+    """Gets or creates a section with the given name."""
+    for section in self.sections:
+      if section.name == name:
+        return section
+    new_section = Section(name)
+    self.sections.append(new_section)
+    return new_section
+
+
+  def WriteToFile(self, path):
+    """Outputs the Config to a .cnf files."""
+    with open(path, 'w') as out:
+      for section in self.sections:
+        section.WriteTo(out)