(mail-send): Complain about invalid header line.

1 files changed, 9 insertions, 1 deletions

diff --git a/lisp/mail/sendmail.el b/lisp/mail/sendmail.el
index 9437cf2542a..3ead946218f 100644
--- a/lisp/mail/sendmail.el
+++ b/lisp/mail/sendmail.el
@@ -575,6 +575,13 @@ the user from the mailer."
                   (or (y-or-n-p "Message contains non-ASCII characters; send anyway? ")
                       (error "Aborted"))
                 (error "Message contains non-ASCII characters"))))
+        ;; Complain about any invalid line.
+        (goto-char (point-min))
+        (while (not (looking-at (regexp-quote mail-header-separator)))
+          (unless (looking-at "[ \t]\\|.*:\\|$")
+            (push-mark opoint)
+            (error "Invalid header line (maybe a continuation line lacks initial whitespace)"))
+          (forward-line 1))
         (goto-char opoint)
         (run-hooks 'mail-send-hook)
         (message "Sending...")
@@ -633,10 +640,11 @@ the user from the mailer."
           (if mail-aliases
               (expand-mail-aliases (point-min) delimline))
           (goto-char (point-min))
-          ;; ignore any blank lines in the header
+          ;; Ignore any blank lines in the header
           (while (and (re-search-forward "\n\n\n*" delimline t)
                       (< (point) delimline))
             (replace-match "\n"))
+          (goto-char (point-min))
           (let ((case-fold-search t))
             (goto-char (point-min))
             (while (re-search-forward "^Resent-\\(to\\|cc\\|bcc\\):" delimline t)