Make it possible to view S/MIME verified emails

* lisp/gnus/mm-decode.el (mm-possibly-verify-or-decrypt): When
dissecting the result, we need a header (bug#18393).

* lisp/gnus/mm-view.el (mm-view-pkcs7-verify): Insert the verified
string.

* lisp/gnus/smime.el (smime-verify-region): Return the verified
string.

3 files changed, 16 insertions, 17 deletions

diff --git a/lisp/gnus/mm-decode.el b/lisp/gnus/mm-decode.el
index 673098bcb68..42bf5f8081c 100644
--- a/lisp/gnus/mm-decode.el
+++ b/lisp/gnus/mm-decode.el
@@ -1672,6 +1672,8 @@ If RECURSIVE, search recursively."
                     (t (y-or-n-p
                         (format "Decrypt (S/MIME) part? "))))
                    (mm-view-pkcs7 parts from))
+          (goto-char (point-min))
+          (insert "Content-type: text/plain\n\n")
           (setq parts (mm-dissect-buffer t)))))
      ((equal subtype "signed")
       (unless (and (setq protocol
@@ -1739,6 +1741,7 @@ If RECURSIVE, search recursively."
             (mm-set-handle-multipart-parameter
              mm-security-handle 'gnus-details
              (format "Unknown encrypt protocol (%s)" protocol)))))))
+    ;; Check the results (which are now in `parts').
     (let ((info (get-text-property 0 'gnus-info (car mm-security-handle))))
       (if (or (not info)
               (equal info "")
diff --git a/lisp/gnus/mm-view.el b/lisp/gnus/mm-view.el
index 02d99200a35..b66d152fa63 100644
--- a/lisp/gnus/mm-view.el
+++ b/lisp/gnus/mm-view.el
@@ -588,18 +588,9 @@ If MODE is not set, try to find mode automatically."
       (mm-insert-headers "application/pkcs7-mime" "base64" "smime.p7m")
       (insert-buffer-substring (mm-handle-buffer handle))
       (setq verified (smime-verify-region (point-min) (point-max))))
-    (goto-char (point-min))
-    (mm-insert-part handle)
-    (if (search-forward "Content-Type: " nil t)
-        (delete-region (point-min) (match-beginning 0)))
-    (goto-char (point-max))
-    (if (re-search-backward "--\r?\n?" nil t)
-        (delete-region (match-end 0) (point-max)))
-    (unless verified
+    (if verified
+        (insert verified)
       (insert-buffer-substring smime-details-buffer)))
-  (goto-char (point-min))
-  (while (search-forward "\r\n" nil t)
-    (replace-match "\n"))
   t)
 
 (autoload 'epg-decrypt-string "epg")
diff --git a/lisp/gnus/smime.el b/lisp/gnus/smime.el
index b7ec033603f..d8131c60dbe 100644
--- a/lisp/gnus/smime.el
+++ b/lisp/gnus/smime.el
@@ -371,16 +371,21 @@ Any details (stdout and stderr) are left in the buffer specified by
                                (expand-file-name smime-CA-file)))
                      (if smime-CA-directory
                          (list "-CApath"
-                               (expand-file-name smime-CA-directory))))))
+                               (expand-file-name smime-CA-directory)))))
+        (input-buffer (current-buffer)))
     (unless CAs
       (error "No CA configured"))
     (if smime-crl-check
         (cl-pushnew smime-crl-check CAs :test #'equal))
-    (if (apply 'smime-call-openssl-region b e (list smime-details-buffer t)
-               "smime" "-verify" "-out" "/dev/null" CAs)
-        t
-      (insert-buffer-substring smime-details-buffer)
-      nil)))
+    (with-temp-buffer
+      (let ((result-buffer (current-buffer)))
+        (with-current-buffer input-buffer
+          (if (apply 'smime-call-openssl-region b e (list result-buffer
+                                                          smime-details-buffer)
+                     "smime" "-verify" "-out" "-" CAs)
+              (with-current-buffer result-buffer
+                (buffer-string))
+            nil))))))
 
 (defun smime-noverify-region (b e)
   "Verify integrity of S/MIME message in region between B and E.