This is more RFC compliant (see issue) and fixes a problem with
signature verifiers rejecting the part when signed. There is some
amount of backward compatibility concern here since it changes
the output, but the RFC issue coupled with fixing the problem
with signature verifiers seems worth the small risk of breaking
code that depends on the current incorrect output.
Also add running of test_email_renamed to the email regrtest. It contains
tests that the base email/tests/test_email.py does not, which I discovered
while trying to backport this test for confirmation of the behavior.
svn+ssh://pythondev@svn.python.org/python/branches/py3k
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r87873 | r.david.murray | 2011-01-08 21:35:24 -0500 (Sat, 08 Jan 2011) | 12 lines
#5871: protect against header injection attacks.
This makes Header.encode throw a HeaderParseError if it winds up
formatting a header such that a continuation line has no leading
whitespace and looks like a header. Since Header accepts values
containing newlines and preserves them (and this is by design), without
this fix any program that took user input (say, a subject in a web form)
and passed it to the email package as a header was vulnerable to header
injection attacks. (As far as we know this has never been exploited.)
Thanks to Jakub Wilk for reporting this vulnerability.
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