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Fixes #148 #149

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Mar 21, 2023
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18 changes: 13 additions & 5 deletions src/pytds/tls.py
Original file line number Diff line number Diff line change
Expand Up @@ -105,11 +105,19 @@ def validate_host(cert, name):
ext = cert.get_extension(i)
if ext.get_short_name() == b'subjectAltName':
s = str(ext)
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Please refactor this code: extract logic inside this if branch into its own method is_san_matching(san: str, host_name: str): bool.

Also add unit tests for that method for following conditions:

  • exact SAN match
  • wildcard SAN match
  • SAN mismatch

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I added a number of tests in tls_san_test.py, I hope thats correct this way?

# SANs are usually have form like: DNS:hostname
if s.startswith('DNS:') and s[4:] == s_name:
return True

# TODO handle wildcards
items = s.split(',')
for item in items:
dnsentry = item.strip()
# SANs are usually have form like: DNS:hostname
if dnsentry.startswith('DNS:') and s[4:] == s_name:
return True
if dnsentry.startswith('DNS:*.'): # support for wildcards, but only at the first position
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It would be better to extract SAN host name suffix before previous condition, and then check host name for exact match and for wildcard match. Instead of checking for DNS: prefix twice

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@aersam aersam Mar 21, 2023

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I did that refactoring, hope it's fine now

afterstar_parts = dnsentry[6:]
afterstar_parts_sname = '.'.join(s_name.split('.')[1:]) # remove first part of dns name
if afterstar_parts == afterstar_parts_sname:
return True

# TODO check if wildcard is needed in CN as well
return False


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