Double Carriage return breaks header ..

[Patrik Henningsson]

John Fawcett wrote:
> I found out that as I'm using amavis, the message arrives ok.
> Amavis "corrects" the bad header and adds an additional header:
> 
> X-Amavis-Alert: BAD HEADER Improper use of control character (char 0D
> hex) in message header 'Subject'
>      Subject: TEST\r\n ^
> 
> If I take amavis out of the equation I see the same behaviour as you.

I'm also running amavis and i get the "BAD HEADER" but i can't see that 
amavis is "correcting" anything for me.

> I can confirm this is nothing to do with spool_copy_msg().
> When spool_copy_msg() receives the input stream, the headers have
> all been previous read from the stream.
> 
> The interpretation of the end of headers is in
> spool_fill_hdrcache(), when a call to parseheader() returns without
> a header name filled in.
> 
> It seems as though parseheader() will accept (apart from the correct
> \r\n) also bare \r or bare \n as the end of a line and outputs \r\n.
> 
> Removing bare \r instead of interpreting as "end of line" can
> probably be addressed in parseheader(), but why have
> logic to correct bare \r and bare \n in two different places
> (for headers in parseheader() and for bodies in spool_copy_msg()).
> This is a problem common to  headers and bodies so really this needs
> a more structural change. General character checking and correcting
> should be done by passing the stream through a filter function, then
> parseheader() and spool_copy_msg() would only have to worry about
> dealing with well-formed messages or carrying out checks which are
> specific to headers or bodies.
> 
> An advantage of this would also be to introduce the nul char
> check into headers which is only present in spool_copy_msg().
> 
> I think before anyone does a patch some guidance is needed from
> a project committer to avoid going the wrong way.

Should we move this thread to cyrus-devel?

> John
> ---
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