Re: [Python-Dev] Changing string constants to byte arrays ([Python-checkins] r55119 - in python/branches/py3k-struni/Lib: codecs.py test/test_codecs.py)
Hi Walter, if the bytes type does turn out to be a mutable type as suggested in PEP 358, then please make sure that no code (C code in particular), relies on the constantness of these byte objects. This is especially important when it comes to codecs, since the error callback logic would allow the callback to manipulate the byte object contents and length without the codec taking note of this change. I expect there to be other places in the interpreter which would break as well. Otherwise, you end up opening the door for segfaults and easy DOS attacks on Python3. Regards, -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, May 04 2007) Python/Zope Consulting and Support ...http://www.egenix.com/ mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 On 2007-05-04 15:05, walter.doerwald wrote: Author: walter.doerwald Date: Fri May 4 15:05:09 2007 New Revision: 55119 Modified: python/branches/py3k-struni/Lib/codecs.py python/branches/py3k-struni/Lib/test/test_codecs.py Log: Make the BOM constants in codecs.py bytes. Make the buffered input for decoders a bytes object. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Changing string constants to byte arrays ([Python-checkins] r55119 - in python/branches/py3k-struni/Lib: codecs.py test/test_codecs.py)
M.-A. Lemburg wrote: Hi Walter, if the bytes type does turn out to be a mutable type as suggested in PEP 358, it is. then please make sure that no code (C code in particular), relies on the constantness of these byte objects. This is especially important when it comes to codecs, since the error callback logic would allow the callback to manipulate the byte object contents and length without the codec taking note of this change. Encoding is not a problem because the error callback never sees or returns a byte object. However decoding is a problem. After the callback returns the codec has to recalculate it's variables. I expect there to be other places in the interpreter which would break as well. Otherwise, you end up opening the door for segfaults and easy DOS attacks on Python3. True, registering an even callback could crash the interpreter. Seems we have to update all decoding functions. Servus, Walter ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Changing string constants to byte arrays ([Python-checkins] r55119 - in python/branches/py3k-struni/Lib: codecs.py test/test_codecs.py)
M.-A. Lemburg schrieb: Hi Walter, if the bytes type does turn out to be a mutable type as suggested in PEP 358, then please make sure that no code (C code in particular), relies on the constantness of these byte objects. This is especially important when it comes to codecs, since the error callback logic would allow the callback to manipulate the byte object contents and length without the codec taking note of this change. I expect there to be other places in the interpreter which would break as well. Otherwise, you end up opening the door for segfaults and easy DOS attacks on Python3. If the user does not need to change these bytes objects and this is needed in more places, adding an immutable flag for internal bytes objects only settable from C, or even an immutable byte base class might be an idea. Georg -- Thus spake the Lord: Thou shalt indent with four spaces. No more, no less. Four shall be the number of spaces thou shalt indent, and the number of thy indenting shall be four. Eight shalt thou not indent, nor either indent thou two, excepting that thou then proceed to four. Tabs are right out. ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
Re: [Python-Dev] Changing string constants to byte arrays ([Python-checkins] r55119 - in python/branches/py3k-struni/Lib: codecs.py test/test_codecs.py)
On 2007-05-04 18:53, Georg Brandl wrote: M.-A. Lemburg schrieb: Hi Walter, if the bytes type does turn out to be a mutable type as suggested in PEP 358, then please make sure that no code (C code in particular), relies on the constantness of these byte objects. This is especially important when it comes to codecs, since the error callback logic would allow the callback to manipulate the byte object contents and length without the codec taking note of this change. I expect there to be other places in the interpreter which would break as well. Otherwise, you end up opening the door for segfaults and easy DOS attacks on Python3. If the user does not need to change these bytes objects and this is needed in more places, adding an immutable flag for internal bytes objects only settable from C, or even an immutable byte base class might be an idea. +1 I also suggest making all bytes literals immutable to avoid running into any issues like the above. -- Marc-Andre Lemburg eGenix.com Professional Python Services directly from the Source (#1, May 04 2007) Python/Zope Consulting and Support ...http://www.egenix.com/ mxODBC.Zope.Database.Adapter ... http://zope.egenix.com/ mxODBC, mxDateTime, mxTextTools ...http://python.egenix.com/ Try mxODBC.Zope.DA for Windows,Linux,Solaris,MacOSX for free ! eGenix.com Software, Skills and Services GmbH Pastor-Loeh-Str.48 D-40764 Langenfeld, Germany. CEO Dipl.-Math. Marc-Andre Lemburg Registered at Amtsgericht Duesseldorf: HRB 46611 ___ Python-Dev mailing list Python-Dev@python.org http://mail.python.org/mailman/listinfo/python-dev Unsubscribe: http://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
