sslutil: synchronize hostname matching logic with CPython
sslutil contains its own hostname matching logic. CPython has code
for the same intent. However, it is only available to Python 2.7.9+
(or distributions that have backported 2.7.9's ssl module
improvements).
This patch effectively imports CPython's hostname matching code
from its ssl.py into sslutil.py. The hostname matching code itself
is pretty similar. However, the DNS name matching code is much more
robust and spec conformant.
As the test changes show, this changes some behavior around
wildcard handling and IDNA matching. The new behavior allows
wildcards in the middle of words (e.g. 'f*.com' matches 'foo.com')
This is spec compliant according to RFC 6125 Section 6.5.3 item 3.
There is one test where the matcher is more strict. Before,
'*.a.com' matched '.a.com'. Now it doesn't match. Strictly speaking
this is a security vulnerability.
# See http://EditorConfig.org for the specification
root = true
[*.py]
indent_size = 4
indent_style = space
trim_trailing_whitespace = true
[*.{c,h}]
indent_size = 8
indent_style = tab
trim_trailing_whitespace = true