bug#42398: 26.3; mm-view-pkcs7-verify not using easypg when set

[Timothy J. Miller]

When EasyPG is enabled, multipart/signed and application/pkcs7-mime
enveloped messages are properly handled.

However, application/pkcs7-mime messages of type signed (aka "opaque
signed") are passed off to smime-verify-region, which is incorrect.

This also happens with messages that are signed and encrypted, in that
case the outer envelope is properly handled, but the inner message is of
type application/pkcs7-mime signed, which then follows the same from
through mm-view-pkcs7.

Backtrace below, sample message attached.

smime-message
Description: opaque-signed message

-- T

Debugger entered--Lisp error: (error "No CA configured")
  signal(error ("No CA configured"))
  error("No CA configured")
  smime-verify-region(1 6638)
  mm-view-pkcs7-verify((#<buffer  *mm*-886728> ("application/pkcs7-mime" (name 
. "smime.p7m") (smime-type . "signed-data")) base64 nil ("attachment" (filename 
. "smime.p7m")) nil nil nil))
  mm-view-pkcs7((#<buffer  *mm*-886728> ("application/pkcs7-mime" (name . 
"smime.p7m") (smime-type . "signed-data")) base64 nil ("attachment" (filename . 
"smime.p7m")) nil nil nil) "tmiller@mitre.org")
  mm-possibly-verify-or-decrypt((#<buffer  *mm*-886728> 
("application/pkcs7-mime" (name . "smime.p7m") (smime-type . "signed-data")) 
base64 nil ("attachment" (filename . "smime.p7m")) nil nil nil) 
("application/pkcs7-mime" (name . "smime.p7m") (smime-type . "signed-data")) 
"tmiller@mitre.org")
  mm-dissect-buffer(nil t)
  gnus-display-mime(nil)
  #f(compiled-function (&optional ihandles) #<bytecode 0x4c10a7d5>)()
  gnus-article-prepare-display()
  mu4e~view-gnus((:docid 14291 :subject "opaque signed" :date (24336 18959 0) 
:size 10513 :message-id "C1BAD6D4-53C0-402D-9F23-57211A8221B8@MITRE.ORG" :path 
"/Users/tmiller/Maildir/mitre/INBOX/cur/1594903081.62000_1.MM235917-PC,U=4603:2,S"
 :maildir "/mitre/INBOX" :priority normal :flags (seen attach) :parts ((:index 
1 :name "smime.p7m" :mime-type "application/pkcs7-mime" :type (leaf attachment) 
:attachment t :size 6477)) :from (("Timothy J Miller" . "tmiller@mitre.org")) 
:to (("Timothy J Miller" . "tmiller@mitre.org")) :user-agent 
"Microsoft-MacOutlook/16.38.20061401"))
  mu4e-view((:docid 14291 :subject "opaque signed" :date (24336 18959 0) :size 
10513 :message-id "C1BAD6D4-53C0-402D-9F23-57211A8221B8@MITRE.ORG" :path 
"/Users/tmiller/Maildir/mitre/INBOX/cur/1594903081.62000_1.MM235917-PC,U=4603:2,S"
 :maildir "/mitre/INBOX" :priority normal :flags (seen attach) :parts ((:index 
1 :name "smime.p7m" :mime-type "application/pkcs7-mime" :type (leaf attachment) 
:attachment t :size 6477)) :from (("Timothy J Miller" . "tmiller@mitre.org")) 
:to (("Timothy J Miller" . "tmiller@mitre.org")) :user-agent 
"Microsoft-MacOutlook/16.38.20061401"))
  mu4e~headers-view-handler((:docid 14291 :subject "opaque signed" :date (24336 
18959 0) :size 10513 :message-id 
"C1BAD6D4-53C0-402D-9F23-57211A8221B8@MITRE.ORG" :path 
"/Users/tmiller/Maildir/mitre/INBOX/cur/1594903081.62000_1.MM235917-PC,U=4603:2,S"
 :maildir "/mitre/INBOX" :priority normal :flags (seen attach) :parts ((:index 
1 :name "smime.p7m" :mime-type "application/pkcs7-mime" :type (leaf attachment) 
:attachment t :size 6477)) :from (("Timothy J Miller" . "tmiller@mitre.org")) 
:to (("Timothy J Miller" . "tmiller@mitre.org")) :user-agent 
"Microsoft-MacOutlook/16.38.20061401"))
  mu4e~proc-filter(#<process  *mu4e-proc*> "\37624b\377(:view (\n\011:docid 
14291\n\011:subject \"opaque signed\"\n\011:date (24336 18959 0)\n\011:size 
10513\n\011:message-id 
\"C1BAD6D4-53C0-402D-9F23-57211A8221B8@MITRE.ORG\"\n\011:path 
\"/Users/tmiller/Maildir/mitre/INBOX/cur/1594903081.62000_1.MM235917-PC,U=4603:2,S\"\n\011:maildir
 \"/mitre/INBOX\"\n\011:priority normal\n\011:flags (seen attach)\n\011:parts 
((:index 1 :name \"smime.p7m\" :mime-type \"application/pkcs7-mime\" :type 
(leaf attachment) :attachment t  :size 6477  ))\n\011:from ((\"Timothy J 
Miller\" . \"tmiller@mitre.org\"))\n\011:to ((\"Timothy J Miller\" . 
\"tmiller@mitre.org\"))\n\011:user-agent 
\"Microsoft-MacOutlook/16.38.20061401\"\n)\n)\n\n;; mu> ")


In GNU Emacs 26.3 (build 1, x86_64-apple-darwin18.5.0, Carbon Version 158 
AppKit 1671.4)
 of 2020-03-24 built on Traviss-Mac.local
Repository revision: 9827e0bc3344ce5da9be2e2390bc6e319a3a94d8
Windowing system distributor 'Apple Inc.', version 10.15.5
Recent messages:
Entering debugger...
Mark set [2 times]
(New file)
Mark set
mwheel-scroll: Beginning of buffer [3 times]
Saving file /Users/tmiller/projects/scratch/smime-error...
Wrote /Users/tmiller/projects/scratch/smime-error
Making completion list...
mwheel-scroll: Beginning of buffer [4 times]
<s-backspace> is undefined

Configured using:
 'configure --with-mac
 
--enable-mac-app=/Users/travis/build/railwaycat/homebrew-emacsmacport/build-scripts/emacs-source/tmproot
 
--prefix=/Users/travis/build/railwaycat/homebrew-emacsmacport/build-scripts/emacs-source/tmproot
 --enable-mac-self-contained --with-modules'

Configured features:
NOTIFY ACL GNUTLS LIBXML2 ZLIB TOOLKIT_SCROLL_BARS MODULES THREADS LCMS2

Important settings:
  value of $LANG: en-US.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Fundamental

Minor modes in effect:
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  global-flycheck-mode: t
  projectile-mode: t
  eyebrowse-mode: t
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  xterm-mouse-mode: t
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  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mac-mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
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  auto-composition-mode: t
  auto-encryption-mode: t
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Load-path shadows:
None found.

Features:
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Memory information:
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 (strings 32 187260 8629)
 (string-bytes 1 6418239)
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