[Python-bugs-list] [ python-Bugs-473009 ] binascii_b2a_base64() improper str limit

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Sat, 20 Oct 2001 06:30:12 -0700


Bugs item #473009, was opened at 2001-10-19 21:42
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Category: Python Library
Group: Python 2.1.1
Status: Open
Resolution: None
Priority: 5
Submitted By: Dave Cinege (dcinege)
Assigned to: Nobody/Anonymous (nobody)
Summary: binascii_b2a_base64() improper str limit

Initial Comment:
Modules/binascii.c
binascii_b2a_base64() contains the following 
restrictive code:
	if ( bin_len > BASE64_MAXBIN ) {
		PyErr_SetString(Error, "Too much data 
for base64 line");
		return NULL;
	}

This is an error. The base64 method of encoding data 
has no length limitation. The MIME message RCF has 
such a limitation of base64 encoded data. The 
function should not assume it's only input must be 
MIME compatible. The base64 python module itself
is designed for MIME I/O only, and properly limits 
itself. The binascii function should be left raw.

binascii_a2b_base64() properly accepts input of any 
size.

How I came across this bug: I use base64 to ascii
armor binary data in log entries in a distributed 
network monitoring system. For the sake of ease of 
parsing (human and machine) all log entries are 
delimited by a single line. I commonly have unbroken 
base64 encoded fields of 64KB in size or greater.

Unfortunatly I am unable to encode this data like 
this:
result64 = binascii.b2a_base64(s)
I must do this:
result64 = re.sub('[ |\n]','',base64.encodestring(s))
Which is *much* slower.  : <

I feel this is an outright bug and should be 
corrected. If their is some argument for backward 
compatibly an optional function argument should be 
present to allow bypassing this limitation.




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>Comment By: Martin v. Löwis (loewis)
Date: 2001-10-20 06:30

Message:
Logged In: YES 
user_id=21627

Can you cite any relevant standard that defines base64 to 
work in that way? Base64 is defined in RFC 2045 section 
6.8., which clearly says

  The encoded output stream must be represented in lines 
of no more than 76 characters each.



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