Broken display of clearsigned PGP message

[Andreas Seltenreich <andreas+ding@gate450.dyndns.org>]

There is a report in de.comm.software.gnus about a clearsigned PGP
message being displayed incorrectly (<URL:news:874putv834.fsf@sopos.org>).
It turned out mm-uu-pgp-signed-extract-1 stumbled across whitespace
contained in the line following the Hash header of the message:

--8<---------------cut here---------------start------------->8---
\-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
 
[signed text]
--8<---------------cut here---------------end--------------->8---

I'm not sure if this message is legal according to RFC 2440.  In 6.2
it states that Armor Headers are followed by a blank line, which is
defined as "zero-length, or containing only whitespace", however in
7. it uses the term "empty line" when describing Armor Headers in
cleartext signatures.

IMHO we should follow "be liberal in what you accept" here, especially
since GnuPG considers the message legal.  Should I apply the attached
patch to v5-10 and HEAD?  Can anyone imagine regressions?

diff -u -r6.29.2.24 mm-uu.el
--- mm-uu.el	28 Apr 2006 05:17:32 -0000	6.29.2.24
+++ mm-uu.el	27 Sep 2006 16:28:24 -0000
@@ -373,7 +373,7 @@
 	   mm-security-handle 'gnus-details
 	   (format "Clear verification not supported by `%s'.\n" mml2015-use))))
       (goto-char (point-min))
-      (if (search-forward "\n\n" nil t)
+      (if (re-search-forward "\n[\t ]*\n" nil t)
 	  (delete-region (point-min) (point)))
       (if (re-search-forward mm-uu-pgp-beginning-signature nil t)
 	  (delete-region (match-beginning 0) (point-max)))