Hi,
We got a bug report from
someone using IBM's Lotus suite (I think for both
their MUA and MTA).
Their users would often send messages where all the
content was in
the subject and they didn't bother sending any message
content. I'm
not sure if it's due to an apparently uncommon behavior for
their
particular MUA or their MTA, but every one of these messages was
coming
through with data in a form that looked like this:
"Subject:
howdy\r\n.\r\n"
Rather than including the blank line that one
might expect to follow
headers, since it's required in the event that
a message body is present:
"Subject: howdy\r\n\r\n.\r\n"
The
customer reported these messages were having their subjects stripped;
additional
testing indicted all existing headers were being stripped. It
looks
like this is because the loop that processes message data in
Qpsmtpd::SMTP::data_respond()
and creates a Mail::Header object which is
later used to write out
the header in delivery, only works if a blank line
exists after the
header, e.g. the second form above. The following is all
I could
find in RFC 5322 that elaborated on this blank line, which
obviously
must exist if a message body is included:
"A message consists of
header fields (collectively called "the header
section of the
message") followed, optionally, by a body. The header
section is a
sequence of lines of characters with special syntax as
defined in
this specification. The body is simply a sequence of
characters that
follows the header section and is separated from the
header section
by an empty line (i.e., a line with nothing preceding the
CRLF)."
I
read this as implicitly allowing the exclusion of this blank line if
there
is no message body: the specification for the blank line is only
mentioned
in the description of the body, which is itself described as
optional.
Considering we haven't run into this bug in years of usage, I
assume
it's unconventional to exclude the blank line, but it looks like it
is
legitimate syntax.
At any rate this was effecting multiple
legitimate end users so we put
together the attached patch, which
pulls the header building into its own
sub which is then called
inside the loop if we reach the blank line
indicating the header
section is complete; otherwise, it's called outside
of the loop if we
have no more message data, indicating the header section
is
complete. Sorry I'm not putting this on a github fork, I still don't
have
my git stuff together, I may never get around to it but I thought you
guys
might find this useful.
-Jared
