ietf-dkim
[Top] [All Lists]

Re: [ietf-dkim] ISSUE: tag l=2 and dealing with leading blank lines for SIMPLE c14n.

2007-01-25 15:41:07


--On January 24, 2007 2:08:24 PM -0500 Hector Santos <hsantos(_at_)santronics(_dot_)com> wrote:

At the very least, Eric should add a statement about omitting the
l= tag   to avoid any signer concern about partial hashing body
limit replay exploits.

There are already several warnings in the draft about the dangers of using "l=". We know that the point of "l=" is to allow appending of trailers, as Charles pointed out. We also know that it creates a risk of exploitation, and there are warnings about that in sections 3.5 and 8.1.

And frankly, I don't see why a leading <CRLF> is a special case. Adding a special warning about "l=2" and <CRLF> just seems unnecessary, and opens up a whole can of worms. Suppose the body begins with "--" (not unlikely in a MIME message) --- should this be specifically mentioned as well? If it begins with two <CRLF>s and has "l=4", it is essentially the same case. Suppose it only signs to the end of the first MIME separator? Suppose the message begins "Dear " and has "l=5", or "<CRLF><CRLF>--On " and "l=9" (as this message does)?

eric
_______________________________________________
NOTE WELL: This list operates according to http://mipassoc.org/dkim/ietf-list-rules.html

<Prev in Thread] Current Thread [Next in Thread>