runtime(gpg): Mark dangerous use-embedded-filename with WarningMsg

The syntax highlighter is likely to encourage people to use the listed
commands.

But `use-embedded-filename` is a dangerous option that can cause GnuPG
to write arbitrary data to arbitrary files whenever GnuPG encounters
malicious data.

GnuPG upstream explicitly warns against using this option:

https://dev.gnupg.org/T4500
https://dev.gnupg.org/T6972

However, since this is a valid option, we cannot just drop it from the
syntax script. Instead, let's mark it with the WarningMsg highlighting
to make it obvious, that this option is different (and should not be
used for security reasons).

closes: #13961

Co-authored-by: Daniel Kahn Gillmor <dkg@fifthhorseman.net>
Signed-off-by:  Christian Brabandt <cb@256bit.org>

diff --git a/runtime/syntax/gpg.vim b/runtime/syntax/gpg.vim
index c7f3584ff08f1caa25b6cb47c89c7c772c20b388..2728ecfccd750a2ae0cd10a6ff4d2c07d74a9571 100644 (file)
--- a/runtime/syntax/gpg.vim
+++ b/runtime/syntax/gpg.vim
@@ -1,9 +1,13 @@
 " Vim syntax file
 " Language:            gpg(1) configuration file
+" Maintainer: This file is looking for a maintainer!
 " Previous Maintainer: Nikolai Weibull <now@bitwi.se>
-" Latest Revision:     2010-10-14
-" Updated:             2023-01-23 @ObserverOfTime: added a couple of keywords
+" Latest Revision:     2024-02-11
+" Updated:             
+"     2023-01-23 @ObserverOfTime: added a couple of keywords
 "                      2023-03-21 Todd Zullinger <tmz@pobox.com>: sync with gnupg-2.4.0
+"                      2024-02-10 Daniel Kahn Gillmor <dkg@fifthhorseman.net>:
+"                                 mark use-embedded-filename as warning for security reasons
 
 if exists("b:current_syntax")
   finish
@@ -21,7 +25,7 @@ syn region  gpgComment        contained display oneline start='#' end='$'
 
 syn match   gpgID      contained display '\<\(0x\)\=\x\{8,}\>'
 
-syn match   gpgBegin   display '^' skipwhite nextgroup=gpgComment,gpgOption,gpgCommand
+syn match   gpgBegin   display '^' skipwhite nextgroup=gpgComment,gpgOption,gpgOptionDeprecated,gpgCommand
 
 syn keyword gpgCommand contained skipwhite nextgroup=gpgArg
                        \ change-passphrase check-sig check-signatures
@@ -41,6 +45,7 @@ syn keyword gpgCommand        contained skipwhite nextgroup=gpgArg
                        \ quick-set-expire quick-set-primary-uid quick-sign-key
                        \ quick-update-pref receive-keys recv-keys refresh-keys
                        \ search-keys show-key show-keys sign-key tofu-policy
+
 syn keyword gpgCommand contained skipwhite nextgroup=gpgArgError
                        \ card-edit card-status change-pin check-trustdb
                        \ clear-sign clearsign dearmor dearmour decrypt
@@ -97,6 +102,7 @@ syn keyword gpgOption        contained skipwhite nextgroup=gpgArg
                        \ trusted-key trust-model try-secret-key ttyname
                        \ ttytype ungroup user verify-options weak-digest
                        \ xauthority
+
 syn keyword gpgOption  contained skipwhite nextgroup=gpgArgError
                        \ allow-freeform-uid allow-multiple-messages
                        \ allow-multisig-verification allow-non-selfsigned-uid
@@ -145,7 +151,7 @@ syn keyword gpgOption       contained skipwhite nextgroup=gpgArgError
                        \ no-sk-comments no-skip-hidden-recipients
                        \ no-symkey-cache not-dash-escaped no-textmode
                        \ no-throw-keyids no-tty no-use-agent
-                       \ no-use-embedded-filename no-utf8-strings no-verbose
+                       \ no-utf8-strings no-verbose
                        \ no-version only-sign-text-ids openpgp
                        \ override-compliance-check pgp6 pgp7 pgp8
                        \ preserve-permissions print-dane-records quiet
@@ -155,7 +161,7 @@ syn keyword gpgOption       contained skipwhite nextgroup=gpgArgError
                        \ show-notation show-photos show-policy-url
                        \ show-session-key sk-comments skip-hidden-recipients
                        \ skip-verify textmode throw-keyids try-all-secrets
-                       \ unwrap use-agent use-embedded-filename use-keyboxd
+                       \ unwrap use-agent use-keyboxd
                        \ use-only-openpgp-card utf8-strings verbose version
                        \ warranty with-colons with-fingerprint
                        \ with-icao-spelling with-key-data with-keygrip
@@ -164,6 +170,10 @@ syn keyword gpgOption      contained skipwhite nextgroup=gpgArgError
                        \ with-subkey-fingerprints with-tofu-info with-wkd-hash
                        \ yes
 
+" depcrated for security reasons
+syn keyword gpgOptionDeprecated        contained skipwhite nextgroup=gpgArgError
+      \ use-embedded-filename no-use-embedded-filename
+
 syn match   gpgArg     contained display '\S\+\(\s\+\S\+\)*' contains=gpgID
 syn match   gpgArgError contained display '\S\+\(\s\+\S\+\)*'
 
@@ -171,6 +181,7 @@ hi def link gpgComment      Comment
 hi def link gpgTodo    Todo
 hi def link gpgID      Number
 hi def link gpgOption  Keyword
+hi def link gpgOptionDeprecated        WarningMsg
 hi def link gpgCommand Error
 hi def link gpgArgError        Error