Issue 28262: Header folder folds incorrectly causing MissingHeaderBodySeparatorDefect (original) (raw)

Example:

X-Report-Abuse: =?us-ascii?q?=3Chttps=3A=2F=2Fwww=2Emailitapp=2Ecom=2Freport=5Fabuse=2Ephp=3Fmid=3Dxxx-xxx-xxxx?= =?us-ascii?q?xxxxxxxxxxxxxxxxxxxx=3D=3D-xxx-xx-xx=3E?=

When this header is parsed and reencoded as bytes using policy.default, the result is this:

X-Report-Abuse: <https://www.mailitapp.com/report_abuse.php?mid=xxx-xxx-xxxx xxxxxxxxxxxxxxxxxxxx==-xxx-xx-xx>

Since the header does not require its value to be an encoded word, it is written as plain text. This removes the FWS between the encoded words. However, it appears that it is still seen as a, now invalid, folding point. When an email with this header is parsed again, it causes a MissingHeaderBodySeparatorDefect

It seems to me this has been reported before, but I couldn't lay hands on the issue in a quick search. With this description of the problem and example, I think I see what is wrong. The folding algorithm is probably trying to handle the encoded words one by one instead of joining the ascii-only runs together first.

I'll try to take a look at this this weekend.