[3.11] gh-121650: Encode newlines in headers, and verify headers are sound (GH-122233) #122608
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…s are sound (pythonGH-122233) GH-GH- Encode header parts that contain newlines Per RFC 2047: > [...] these encoding schemes allow the > encoding of arbitrary octet values, mail readers that implement this > decoding should also ensure that display of the decoded data on the > recipient's terminal will not cause unwanted side-effects It seems that the "quoted-word" scheme is a valid way to include a newline character in a header value, just like we already allow undecodable bytes or control characters. They do need to be properly quoted when serialized to text, though. GH-GH- Verify that email headers are well-formed This should fail for custom fold() implementations that aren't careful about newlines. (cherry picked from commit 0976339) Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Bas Bloemsaat <bas@bloemsaat.org> Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
This was referenced Aug 2, 2024
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Per RFC 2047:
It seems that the "quoted-word" scheme is a valid way to include a newline character in a header value, just like we already allow undecodable bytes or control characters.
They do need to be properly quoted when serialized to text, though.
GH-GH- Verify that email headers are well-formed
This should fail for custom fold() implementations that aren't careful about newlines.
(cherry picked from commit 0976339)
📚 Documentation preview 📚: https://cpython-previews--122608.org.readthedocs.build/