[Patches] [ python-Patches-1171487 ] Patch for [ 1170331 ] Error in base64.b32decode

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Patches item #1171487, was opened at 2005-03-27 14:46
Message generated for change (Comment added) made by akuchling
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>Category: Library (Lib)
>Group: Python 2.4
>Status: Closed
>Resolution: Accepted
Priority: 6
Submitted By: logistix (logistix)
>Assigned to: A.M. Kuchling (akuchling)
Summary: Patch for [ 1170331 ] Error in base64.b32decode

Initial Comment:
base64.b32decode didn't decode some things properly. 
Seems to have only impacted characters with a value <
32.  Attached is a fix and a new test.

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>Comment By: A.M. Kuchling (akuchling)
Date: 2005-06-08 18:53

Message:
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Applied; thanks!  I also added a test case that would have
caught the bug.


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Comment By: logistix (logistix)
Date: 2005-03-27 16:43

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Updated patch to reflect another fix.

I originally thought the bug was related to cleanup of a
partial quanta.  It will trigger on any quanta where the
initial hex value is < 0x10.  When this happens part of the
hex code disappears in the initial conversion and is
mistakenly swallowed.  The hex function that was originally
used doesn't zero-pad, but the way the bit shifting works,
it doesn't need to when encoding normal alpha-numeric
characters, so it seemed to work correctly.

This will only cause problems if you are using a character
value of < 0x10 in the 0th, 4th, 8th, 12th, etc positions in
the encoded string.  Otherwise it'll work properly.  Using
"%010x" ensures that you'll get the appropriate zero-padding
if necessary.

Example of more broken code not covered in the original bug:

>>> base64.b32decode(base64.b32encode('\x00aaa'))
'aaa'

Updated patch fixes this case as well.

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