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Re: sig. subpacket & length conflicts?



From: Erron Criddle <ejc@comasp.com>
Subject: sig. subpacket & length conflicts?
Date: Wed, 19 Jul 2000 15:38:46 +0800
Message-ID: <4.3.2.7.0.20000719153136.00b34610@mail.comasp.com>

> As stated in 5.2.3.1, signature subpackets can contain lengths up to 
> 0xFFFFFFFF, however the maximum length as defined for ALL hashable (or 
> unhashable) subpackets is a maximum of 8383 bytes (as indicated by a two 
> octet scalar).

i took "Two-octet scalar octet count" in section 5.2.3 to mean 0 to 255,
as the text says:

     - Two-octet scalar octet count for following hashed subpacket
       data. Note that this is the length in octets of all of the
       hashed subpackets; a pointer incremented by this number will
       skip over the hashed subpackets.

i took the word "scalar" to mean that i should think about section 3.1
(Scalar numbers).  also, in section 5.2.3.1, it is explicitly pointed
out that the subpacket length is:

    similar to the "new" format packet header lengths

and since 5.2.3 itself didn't mention anything, i didn't think to
interpret "two-octet scalar" as similar to the "new" format packet
header length.

to all: is this interpretation (0 - 255) correct?

> So, do we limit the subpacket length to two bytes or redefine that
> maximum allowed total length for all subpackets (of type hashable or
> unhashable) as 0xFFFFFFFF ( up to 5 bytes)?

my guess would be that although you can express length of over 255 (or
8383, whichever is correct) using 2 or 5 octets, that you don't do so
in practice in this context.  if that interpretation is correct,
perhaps a note pointing this out in the text would be helpful for
future readers.