Avoid a regexp overflow in message-goto-body

* lisp/gnus/message.el (message-goto-body-1): Avoid using a
complicated backtracking regexp, because they may overflow on
large headers (bug#21160).

1 files changed, 13 insertions, 3 deletions

diff --git a/lisp/gnus/message.el b/lisp/gnus/message.el
index ce0d9769a5a..9af38c01ed7 100644
--- a/lisp/gnus/message.el
+++ b/lisp/gnus/message.el
@@ -3111,16 +3111,26 @@ M-RET    `message-newline-and-reformat' (break the line and reformat)."
   (message-goto-body-1))
 
 (defun message-goto-body-1 ()
+  "Go to the body and return point."
   (goto-char (point-min))
   (or (search-forward (concat "\n" mail-header-separator "\n") nil t)
-      (search-forward-regexp "[^:]+:\\([^\n]\\|\n[ \t]\\)+\n\n" nil t)))
+      ;; If the message is mangled, find the end of the headers the
+      ;; hard way.
+      (progn
+        ;; Skip past all headers and continuation lines.
+        (while (looking-at "[^:]+:\\|[\t ]+[^\t ]")
+          (forward-line 1))
+        ;; We're now at the first empty line, so perhaps move past it.
+        (when (and (eolp)
+                   (not (eobp)))
+          (forward-line 1))
+        (point))))
 
 (defun message-in-body-p ()
   "Return t if point is in the message body."
   (>= (point)
       (save-excursion
-        (message-goto-body-1)
-        (point))))
+        (message-goto-body-1))))
 
 (defun message-goto-eoh ()
   "Move point to the end of the headers."