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email: multiline encoded headers #91957
Description
Bug report
There seems to be a problem with multiline encoded headers, for example subject headers.
from email import message_from_string, policy
import base64
e = """From: <test@test.com>
To: <test@test.com>
Subject: =?UTF-8?B?0JfQsNGB0YLRgNCw0YXQvtCy0LrQsCAi0JDQu9C40LDQvdGGINCX0LTRgNCw0LLQ?=
=?UTF-8?B?tSIg4oCTINCY0L3QtNC40LLQuNC00YPQsNC70LXQvSDQvdC+0LzQtdGAINC90LAg?=
=?UTF-8?B?0YPQstC10LTQvtC80LvQtdC90LjQtQ==?=
test"""
e = message_from_string(e, policy=policy.default)
s1 = e["Subject"]
try:
e.as_bytes()
except Exception:
print("error")
else:
print("ok")
s = (base64.b64decode("0JfQsNGB0YLRgNCw0YXQvtCy0LrQsCAi0JDQu9C40LDQvdGGINCX0LTRgNCw0LLQ") + base64.b64decode("tSIg4oCTINCY0L3QtNC40LLQuNC00YPQsNC70LXQvSDQvdC+0LzQtdGAINC90LAg")
+ base64.b64decode("0YPQstC10LTQvtC80LvQtdC90LjQtQ==")).decode("utf-8")
del e["Subject"]
e["Subject"] = s
s2 = e["Subject"]
try:
e.as_bytes()
except Exception:
print("error")
else:
print("ok")
print(s1 == s2)
e = """From: <test@test.com>
To: <test@test.com>
Subject: =?UTF-8?B?0JfQsNGB0YLRgNCw0YXQvtCy0LrQsCAi0JDQu9C40LDQvdGGINCX0LTRgNCw0LLQtSIg4oCTINCY0L3QtNC40LLQuNC00YPQsNC70LXQvSDQvdC+0LzQtdGAINC90LAg0YPQstC10LTQvtC80LvQtdC90LjQtQ==?=
test"""
e = message_from_string(e, policy=policy.default)
s3 = e["Subject"]
try:
e.as_bytes()
except Exception:
print("error")
else:
print("ok")
print(s2 == s3)
Your environment
Tested on Python 3.10.4 and 3.11.0a7 on Arch Linux
Activity
wbolster commentedon May 9, 2022
it would help if you described what you believe the problem is, @mdierksen (without forcing others to reverse engineer your example code to try to understand)
mdierksen commentedon May 10, 2022
The first e.as_bytes() causes this exception:
The problem is with the subject header. Extracting the subject as a string works however.
Manually decoding the subject header and replacing it in the email object fixes the problem. Extracting the subject as a string yields the same string as before.
The problem does not occur for encoded headers in a single line, but only for multiline headers that are split up in a certain way.