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bpo-30566: Fix IndexError when using punycode codec #18632

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Merged
berkerpeksag merged 1 commit into from
Feb 25, 2020
Merged

bpo-30566: Fix IndexError when using punycode codec #18632

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bpo-30566: Fix IndexError when using punycode codec 
Trying to decode an invalid string with the punycode codec
shoud raise UnicodeError.
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@berkerpeksag
berkerpeksag committed Feb 24, 2020
commit d860957dcef3cd09cca6db29bb074eca87defeed
2 changes: 1 addition & 1 deletion Lib/encodings/punycode.py
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Original file line number Diff line number Diff line change
Expand Up @@ -143,7 +143,7 @@ def decode_generalized_number(extended, extpos, bias, errors):
digit = char - 22 # 0x30-26
elif errors == "strict":
raise UnicodeError("Invalid extended code point '%s'"
% extended[extpos])
% extended[extpos-1])
else:
return extpos, None
t = T(j, bias)
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12 changes: 12 additions & 0 deletions Lib/test/test_codecs.py
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Expand Up @@ -1343,6 +1343,18 @@ def test_decode(self):
puny = puny.decode("ascii").encode("ascii")
self.assertEqual(uni, puny.decode("punycode"))

def test_decode_invalid(self):
testcases = [
(b"xn--w&", "strict", UnicodeError()),
(b"xn--w&", "ignore", "xn-"),
]
for puny, errors, expected in testcases:
with self.subTest(puny=puny, errors=errors):
if isinstance(expected, Exception):
self.assertRaises(UnicodeError, puny.decode, "punycode", errors)
else:
self.assertEqual(puny.decode("punycode", errors), expected)


# From http://www.gnu.org/software/libidn/draft-josefsson-idn-test-vectors.html
nameprep_tests = [
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2 changes: 2 additions & 0 deletions Misc/NEWS.d/next/Library/2020-02-24-03-45-28.bpo-30566.qROxty.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1,2 @@
Fix :exc:`IndexError` when trying to decode an invalid string with punycode
codec.