Merge Emacs 25.3 fixes

The security patches released for Emacs 25.3 were less drastic
than what we had immediately put into master.  Adjust master to
match 25.3 (Bug#28350).
* lisp/textmodes/enriched.el (enriched-translations):
Re-enable FUNCTION and display translations that are safe.
(enriched-handle-display-prop): Bring back.
(enriched-decode-display-prop): Bring back, but disable
the unsafe part.

1 files changed, 35 insertions, 0 deletions

diff --git a/lisp/textmodes/enriched.el b/lisp/textmodes/enriched.el
index eba7c4ddd83..5319db7c16e 100644
--- a/lisp/textmodes/enriched.el
+++ b/lisp/textmodes/enriched.el
@@ -117,7 +117,12 @@ expression, which is evaluated to get the string to insert.")
 		   (full        "flushboth")
 		   (center      "center"))
     (PARAMETER     (t           "param")) ; Argument of preceding annotation
+    ;; The following are not part of the standard:
+    (FUNCTION      (enriched-decode-foreground "x-color")
+		   (enriched-decode-background "x-bg-color")
+		   (enriched-decode-display-prop "x-display"))
     (read-only     (t           "x-read-only"))
+    (display	   (nil		enriched-handle-display-prop))
     (unknown       (nil         format-annotate-value))
 ;   (font-size     (2           "bigger")       ; unimplemented
 ;		   (-2          "smaller"))
@@ -472,5 +477,35 @@ Return value is \(begin end name positive-p), or nil if none was found."
     (message "Warning: no color specified for <x-bg-color>")
     nil))
 
+;;; Handling the `display' property.
+
+
+(defun enriched-handle-display-prop (old new)
+  "Return a list of annotations for a change in the `display' property.
+OLD is the old value of the property, NEW is the new value.  Value
+is a list `(CLOSE OPEN)', where CLOSE is a list of annotations to
+close and OPEN a list of annotations to open.  Each of these lists
+has the form `(ANNOTATION PARAM ...)'."
+  (let ((annotation "x-display")
+	(param (prin1-to-string (or old new))))
+    (if (null old)
+        (cons nil (list (list annotation param)))
+      (cons (list (list annotation param)) nil))))
+
+(defun enriched-decode-display-prop (start end &optional param)
+  "Decode a `display' property for text between START and END.
+PARAM is a `<param>' found for the property.
+Value is a list `(START END SYMBOL VALUE)' with START and END denoting
+the range of text to assign text property SYMBOL with value VALUE."
+  (let ((prop (when (stringp param)
+		(condition-case ()
+		    (car (read-from-string param))
+		  (error nil)))))
+    (unless prop
+      (message "Warning: invalid <x-display> parameter %s" param))
+    ;; Disabled in Emacs 25.3 to avoid execution of arbitrary Lisp
+    ;; forms in display properties stored within enriched text.
+    ;; (list start end 'display prop)))
+    (list start end)))
 
 ;;; enriched.el ends here