Refactor mm-decode and friends to be explicit about when errors happen

* lisp/gnus/mm-decode.el (mm-sec-status):
(mm-sec-error): New functions to handle decryption problems more
explicitly (bug#18393).
(mm-possibly-verify-or-decrypt): Use the `sec-error' data to
determine whether the operation failed or not.

* lisp/gnus/mml-smime.el: Ditto.

* lisp/gnus/mml2015.el: Used throughout.

4 files changed, 123 insertions, 172 deletions

diff --git a/lisp/gnus/mm-decode.el b/lisp/gnus/mm-decode.el
index 3de7a0464bb..22e7e118e2e 100644
--- a/lisp/gnus/mm-decode.el
+++ b/lisp/gnus/mm-decode.el
@@ -1646,14 +1646,22 @@ If RECURSIVE, search recursively."
             (setq result (buffer-string))))))
     result))
 
-(defvar mm-security-handle nil)
-
 (defsubst mm-set-handle-multipart-parameter (handle parameter value)
   ;; HANDLE could be a CTL.
   (when handle
     (put-text-property 0 (length (car handle)) parameter value
                        (car handle))))
 
+;; Interface functions and variables for the decryption/verification
+;; functions.
+(defvar mm-security-handle nil)
+(defun mm-sec-status (&rest keys)
+  (cl-loop for (key val) on keys by #'cddr
+           do (mm-set-handle-multipart-parameter mm-security-handle key val)))
+
+(defun mm-sec-error (&rest keys)
+  (apply #'mm-sec-status (append '(sec-error t) keys)))
+
 (autoload 'mm-view-pkcs7 "mm-view")
 
 (defun mm-possibly-verify-or-decrypt (parts ctl &optional from)
@@ -1706,9 +1714,8 @@ If RECURSIVE, search recursively."
         (save-excursion
           (if func
               (setq parts (funcall func parts ctl))
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-details
-             (format "Unknown sign protocol (%s)" protocol))))))
+            (mm-sec-error 'gnus-details
+                          (format "Unknown sign protocol (%s)" protocol))))))
      ((equal subtype "encrypted")
       (unless (setq protocol
                     (mm-handle-multipart-ctl-parameter ctl 'protocol))
@@ -1738,22 +1745,23 @@ If RECURSIVE, search recursively."
         (save-excursion
           (if func
               (setq parts (funcall func parts ctl))
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-details
+            (mm-sec-error
+             '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 "")
-              (not (equal subtype "encrypted"))
-              (member "OK" (split-string info "\n")))
+    (let ((err (get-text-property 0 'sec-error (car mm-security-handle))))
+      (if (or (not err)
+              (not (equal subtype "encrypted")))
           parts
         ;; We had an error during decryption.  Report what it is.
         (list
          (mm-make-handle
           (with-current-buffer (generate-new-buffer " *mm*")
             (insert "Error!  Result from decryption:\n\n"
-                    info "\n\n"
+                    (or (get-text-property 0 'gnus-details
+                                           (car mm-security-handle))
+                        "")
+                    "\n\n"
                     (or (get-text-property 0 'gnus-details
                                            (car mm-security-handle))
                         ""))
diff --git a/lisp/gnus/mm-uu.el b/lisp/gnus/mm-uu.el
index a00d64015f2..6143b41bbc1 100644
--- a/lisp/gnus/mm-uu.el
+++ b/lisp/gnus/mm-uu.el
@@ -509,8 +509,8 @@ apply the face `mm-uu-extract'."
                                               'iso-8859-1)))
               (funcall (mml2015-clear-verify-function))))
         (when (and mml2015-use (null (mml2015-clear-verify-function)))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-details
+          (mml2015--status
+           'gnus-details
            (format-message
             "Clear verification not supported by `%s'.\n" mml2015-use)))
         (mml2015-extract-cleartext-signature))
diff --git a/lisp/gnus/mml-smime.el b/lisp/gnus/mml-smime.el
index b2e9b783522..659f2b95289 100644
--- a/lisp/gnus/mml-smime.el
+++ b/lisp/gnus/mml-smime.el
@@ -274,10 +274,9 @@ Whether the passphrase is cached at all is controlled by
       (if (not good-signature)
           (progn
             ;; we couldn't verify message, fail with openssl output as message
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-info "Failed")
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-details
+            (mm-sec-error
+             'gnus-info "Failed"
+             'gnus-details
              (concat "OpenSSL failed to verify message integrity:\n"
                      "-------------------------------------------\n"
                      openssl-output)))
@@ -290,19 +289,18 @@ Whether the passphrase is cached at all is controlled by
             (while (re-search-forward "-----END CERTIFICATE-----" nil t)
               (when (smime-pkcs7-email-region (point-min) (point))
                 (setq addresses (append (smime-buffer-as-string-region
-                                         (point-min) (point)) addresses)))
+                                         (point-min) (point))
+                                        addresses)))
               (delete-region (point-min) (point)))
             (setq addresses (mapcar 'downcase addresses))))
-        (if (not (member (downcase (or (mm-handle-multipart-from ctl) "")) addresses))
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-info "Sender address forged")
+        (if (not (member (downcase (or (mm-handle-multipart-from ctl) ""))
+                         addresses))
+            (mm-sec-error 'gnus-info "Sender address forged")
           (if good-certificate
-              (mm-set-handle-multipart-parameter
-               mm-security-handle 'gnus-info "Ok (sender authenticated)")
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-info "Ok (sender not trusted)")))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-details
+              (mm-sec-status 'gnus-info "Ok (sender authenticated)")
+            (mm-sec-status 'gnus-info "Ok (sender not trusted)")))
+        (mm-sec-status
+         'gnus-details
          (concat "Sender claimed to be: " (mm-handle-multipart-from ctl) "\n"
                  (if addresses
                      (concat "Addresses in certificate: "
@@ -411,24 +409,20 @@ Content-Disposition: attachment; filename=smime.p7m
                                            (cdr handle)
                                            "application/x-pkcs7-signature"
                                            nil t)))))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (setq part (replace-regexp-in-string "\n" "\r\n" part)
             context (epg-make-context 'CMS))
       (condition-case error
           (setq plain (epg-verify-string context (mm-get-part signature) part))
         (error
-         (mm-set-handle-multipart-parameter
-          mm-security-handle 'gnus-info "Failed")
+         (mm-sec-error 'gnus-info "Failed")
          (if (eq (car error) 'quit)
-             (mm-set-handle-multipart-parameter
-              mm-security-handle 'gnus-details "Quit.")
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details (format "%S" error)))
+             (mm-sec-status 'gnus-details "Quit.")
+           (mm-sec-status 'gnus-details (format "%S" error)))
          (throw 'error handle)))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info
+      (mm-sec-status
+       'gnus-info
        (epg-verify-result-to-string (epg-context-result-for context 'verify)))
       handle)))
 
diff --git a/lisp/gnus/mml2015.el b/lisp/gnus/mml2015.el
index 45164ee8f65..c3cf31f1a3c 100644
--- a/lisp/gnus/mml2015.el
+++ b/lisp/gnus/mml2015.el
@@ -191,8 +191,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (unless (setq child (mm-find-part-by-type
                            (cdr handle)
                            "application/octet-stream" nil t))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (with-temp-buffer
         (mm-insert-part child)
@@ -200,21 +199,18 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
               (condition-case err
                   (funcall mml2015-decrypt-function)
                 (error
-                 (mm-set-handle-multipart-parameter
-                  mm-security-handle 'gnus-details (mml2015-format-error err))
+                 (mm-sec-error 'gnus-details (mml2015-format-error err))
                  nil)
                 (quit
-                 (mm-set-handle-multipart-parameter
-                  mm-security-handle 'gnus-details "Quit.")
+                 (mm-sec-error 'gnus-details "Quit.")
                  nil)))
         (unless (car result)
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "Failed")
+          (mm-sec-error 'gnus-info "Failed")
           (throw 'error handle))
         (setq handles (mm-dissect-buffer t)))
       (mm-destroy-parts handle)
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info
+      (mm-sec-status
+       'gnus-info
        (concat "OK"
                (let ((sig (with-current-buffer mml2015-result-buffer
                             (mml2015-gpg-extract-signature-details))))
@@ -281,18 +277,14 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
           (condition-case err
               (funcall mml2015-decrypt-function)
             (error
-             (mm-set-handle-multipart-parameter
-              mm-security-handle 'gnus-details (mml2015-format-error err))
+             (mm-sec-error 'gnus-details (mml2015-format-error err))
              nil)
             (quit
-             (mm-set-handle-multipart-parameter
-              mm-security-handle 'gnus-details "Quit.")
+             (mm-sec-error 'gnus-details "Quit.")
              nil)))
     (if (car result)
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "OK")
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "Failed"))))
+        (mm-sec-status 'gnus-info "OK")
+      (mm-sec-error 'gnus-info "Failed"))))
 
 (defun mml2015-fix-micalg (alg)
   (and alg
@@ -309,8 +301,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                                    ctl 'protocol)
                                   "application/pgp-signature")
                           t))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (with-temp-buffer
         (insert "-----BEGIN PGP SIGNED MESSAGE-----\n")
@@ -329,8 +320,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
             (forward-line)))
         (unless (setq part (mm-find-part-by-type
                             (cdr handle) "application/pgp-signature" nil t))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "Corrupted")
+          (mm-sec-error 'gnus-info "Corrupted")
           (throw 'error handle))
         (save-restriction
           (narrow-to-region (point) (point))
@@ -345,8 +335,8 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                       (prog1
                           (funcall mml2015-verify-function)
                         (if (get-buffer " *mailcrypt stderr temp")
-                            (mm-set-handle-multipart-parameter
-                             mm-security-handle 'gnus-details
+                            (mm-sec-error
+                             'gnus-details
                              (with-current-buffer " *mailcrypt stderr temp"
                                (buffer-string))))
                         (if (get-buffer " *mailcrypt stdout temp")
@@ -358,18 +348,14 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                         (if (get-buffer mc-gpg-debug-buffer)
                             (kill-buffer mc-gpg-debug-buffer)))
                     (error
-                     (mm-set-handle-multipart-parameter
-                      mm-security-handle 'gnus-details (mml2015-format-error err))
+                     (mm-sec-error 'gnus-details (mml2015-format-error err))
                      nil)
                     (quit
-                     (mm-set-handle-multipart-parameter
-                      mm-security-handle 'gnus-details "Quit.")
+                     (mm-sec-error 'gnus-details "Quit.")
                      nil))
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-info "Failed")
+            (mm-sec-error 'gnus-info "Failed")
             (throw 'error handle))))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "OK")
+      (mm-sec-status 'gnus-info "OK")
       handle)))
 
 (defun mml2015-mailcrypt-clear-verify ()
@@ -378,8 +364,8 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
             (prog1
                 (funcall mml2015-verify-function)
               (if (get-buffer " *mailcrypt stderr temp")
-                  (mm-set-handle-multipart-parameter
-                   mm-security-handle 'gnus-details
+                  (mm-sec-error
+                   'gnus-details
                    (with-current-buffer " *mailcrypt stderr temp"
                      (buffer-string))))
               (if (get-buffer " *mailcrypt stdout temp")
@@ -391,17 +377,13 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
               (if (get-buffer mc-gpg-debug-buffer)
                   (kill-buffer mc-gpg-debug-buffer)))
           (error
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details (mml2015-format-error err))
+           (mm-sec-error 'gnus-details (mml2015-format-error err))
            nil)
           (quit
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details "Quit.")
+           (mm-sec-error 'gnus-details "Quit.")
            nil))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "OK")
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "Failed")))
+        (mm-sec-status 'gnus-info "OK")
+      (mm-sec-error 'gnus-info "Failed")))
   (mml2015-extract-cleartext-signature))
 
 (defun mml2015-mailcrypt-sign (cont)
@@ -509,8 +491,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (unless (setq child (mm-find-part-by-type
                            (cdr handle)
                            "application/octet-stream" nil t))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (with-temp-buffer
         (mm-insert-part child)
@@ -520,16 +501,12 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                   (setq decrypt-status
                         (with-current-buffer mml2015-result-buffer
                           (buffer-string)))
-                  (mm-set-handle-multipart-parameter
-                   mm-security-handle 'gnus-details
-                   decrypt-status))
+                  (mm-sec-status 'gnus-details decrypt-status))
               (error
-               (mm-set-handle-multipart-parameter
-                mm-security-handle 'gnus-details (mml2015-format-error err))
+               (mm-sec-error 'gnus-details (mml2015-format-error err))
                nil)
               (quit
-               (mm-set-handle-multipart-parameter
-                mm-security-handle 'gnus-details "Quit.")
+               (mm-sec-error 'gnus-details "Quit.")
                nil))
             (with-current-buffer pgg-output-buffer
               (goto-char (point-min))
@@ -537,27 +514,24 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                 (replace-match "\n" t t))
               (setq handles (mm-dissect-buffer t))
               (mm-destroy-parts handle)
-              (mm-set-handle-multipart-parameter
-               mm-security-handle 'gnus-info "OK")
-              (mm-set-handle-multipart-parameter
-               mm-security-handle 'gnus-details
-               (concat decrypt-status
-                       (when (stringp (car handles))
-                         "\n" (mm-handle-multipart-ctl-parameter
-                               handles 'gnus-details))))
+              (mm-sec-status 'gnus-info "OK"
+                             'gnus-details
+                             (concat decrypt-status
+                                     (when (stringp (car handles))
+                                       "\n" (mm-handle-multipart-ctl-parameter
+                                             handles 'gnus-details))))
               (if (listp (car handles))
                   handles
                 (list handles)))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "Failed")
+          (mm-sec-error 'gnus-info "Failed")
           (throw 'error handle))))))
 
 (defun mml2015-pgg-clear-decrypt ()
   (let ((pgg-errors-buffer mml2015-result-buffer))
     (if (prog1
             (pgg-decrypt-region (point-min) (point-max))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-details
+          (mm-sec-status
+           'gnus-details
            (with-current-buffer mml2015-result-buffer
              (buffer-string))))
         (progn
@@ -568,10 +542,8 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
           (goto-char (point-min))
           (while (search-forward "\r\n" nil t)
             (replace-match "\n" t t))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "OK"))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "Failed"))))
+          (mm-sec-status 'gnus-info "OK"))
+      (mm-sec-error 'gnus-info "Failed"))))
 
 (defun mml2015-pgg-verify (handle ctl)
   (let ((pgg-errors-buffer mml2015-result-buffer)
@@ -581,11 +553,11 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                                        ctl 'protocol)
                                       "application/pgp-signature")
                               t)))
-            (null (setq signature (mm-find-part-by-type
-                                   (cdr handle) "application/pgp-signature" nil t))))
+            (null (setq signature
+                        (mm-find-part-by-type
+                         (cdr handle) "application/pgp-signature" nil t))))
         (progn
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "Corrupted")
+          (mm-sec-error 'gnus-info "Corrupted")
           handle)
       (with-temp-buffer
         (insert part)
@@ -607,29 +579,26 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                   (goto-char (point-min))
                   (while (search-forward "\r\n" nil t)
                     (replace-match "\n" t t))
-                  (mm-set-handle-multipart-parameter
-                   mm-security-handle 'gnus-details
+                  (mm-sec-status
+                   'gnus-details
                    (concat (with-current-buffer pgg-output-buffer
                              (buffer-string))
                            (with-current-buffer pgg-errors-buffer
                              (buffer-string)))))
               (error
-               (mm-set-handle-multipart-parameter
-                mm-security-handle 'gnus-details (mml2015-format-error err))
+               (mm-sec-error 'gnus-details (mml2015-format-error err))
                nil)
               (quit
-               (mm-set-handle-multipart-parameter
-                mm-security-handle 'gnus-details "Quit.")
+               (mm-sec-error 'gnus-details "Quit.")
                nil))
             (progn
               (delete-file signature-file)
-              (mm-set-handle-multipart-parameter
-               mm-security-handle 'gnus-info
+              (mm-sec-error
+               'gnus-info
                (with-current-buffer pgg-errors-buffer
                  (mml2015-gpg-extract-signature-details))))
           (delete-file signature-file)
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "Failed")))))
+          (mm-sec-error 'gnus-info "Failed")))))
   handle)
 
 (defun mml2015-pgg-clear-verify ()
@@ -644,26 +613,23 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
               (goto-char (point-min))
               (while (search-forward "\r\n" nil t)
                 (replace-match "\n" t t))
-              (mm-set-handle-multipart-parameter
-               mm-security-handle 'gnus-details
+              (mm-sec-status
+               'gnus-details
                (concat (with-current-buffer pgg-output-buffer
                          (buffer-string))
                        (with-current-buffer pgg-errors-buffer
                          (buffer-string)))))
           (error
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details (mml2015-format-error err))
+           (mm-sec-error 'gnus-details (mml2015-format-error err))
            nil)
           (quit
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details "Quit.")
+           (mm-sec-error 'gnus-details "Quit.")
            nil))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info
+        (mm-sec-status
+         'gnus-info
          (with-current-buffer pgg-errors-buffer
            (mml2015-gpg-extract-signature-details)))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "Failed")))
+      (mm-sec-error 'gnus-info "Failed")))
   (mml2015-extract-cleartext-signature))
 
 (defun mml2015-pgg-sign (cont)
@@ -807,8 +773,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (unless (setq child (mm-find-part-by-type
                            (cdr handle)
                            "application/octet-stream" nil t))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (setq context (epg-make-context))
       (if (or mml2015-cache-passphrase mml-secure-cache-passphrase)
@@ -820,13 +785,10 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                 mml-secure-secret-key-id-list nil)
         (error
          (mml-secure-clear-secret-key-id-list)
-         (mm-set-handle-multipart-parameter
-          mm-security-handle 'gnus-info "Failed")
+         (mm-sec-error 'gnus-info "Failed")
          (if (eq (car error) 'quit)
-             (mm-set-handle-multipart-parameter
-              mm-security-handle 'gnus-details "Quit.")
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details (mml2015-format-error error)))
+             (mm-sec-status 'gnus-details "Quit.")
+           (mm-sec-status 'gnus-details (mml2015-format-error error)))
          (throw 'error handle)))
       (with-temp-buffer
         (insert plain)
@@ -836,16 +798,15 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
         (setq handles (mm-dissect-buffer t))
         (mm-destroy-parts handle)
         (if (epg-context-result-for context 'verify)
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-info
+            (mm-sec-status
+             'gnus-info
              (concat "OK\n"
                      (mml2015-epg-verify-result-to-string
                       (epg-context-result-for context 'verify))))
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info "OK"))
+          (mm-sec-status 'gnus-info "OK"))
         (if (stringp (car handles))
-            (mm-set-handle-multipart-parameter
-             mm-security-handle 'gnus-details
+            (mm-sec-status
+             'gnus-details
              (mm-handle-multipart-ctl-parameter handles 'gnus-details))))
         (if (listp (car handles))
             handles
@@ -864,13 +825,10 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
               mml-secure-secret-key-id-list nil)
       (error
        (mml-secure-clear-secret-key-id-list)
-       (mm-set-handle-multipart-parameter
-        mm-security-handle 'gnus-info "Failed")
+       (mm-sec-error 'gnus-info "Failed")
        (if (eq (car error) 'quit)
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details "Quit.")
-         (mm-set-handle-multipart-parameter
-          mm-security-handle 'gnus-details (mml2015-format-error error)))))
+           (mm-sec-status 'gnus-details "Quit.")
+         (mm-sec-status 'gnus-details (mml2015-format-error error)))))
     (when plain
       (erase-buffer)
       ;; Treat data which epg returns as a unibyte string.
@@ -879,11 +837,10 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (goto-char (point-min))
       (while (search-forward "\r\n" nil t)
         (replace-match "\n" t t))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info "OK")
+      (mm-sec-status 'gnus-info "OK")
       (if (epg-context-result-for context 'verify)
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-details
+          (mm-sec-status
+           'gnus-details
            (mml2015-epg-verify-result-to-string
             (epg-context-result-for context 'verify)))))))
 
@@ -899,8 +856,7 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
                 (null (setq signature (mm-find-part-by-type
                                        (cdr handle) "application/pgp-signature"
                                        nil t))))
-        (mm-set-handle-multipart-parameter
-         mm-security-handle 'gnus-info "Corrupted")
+        (mm-sec-error 'gnus-info "Corrupted")
         (throw 'error handle))
       (setq part (replace-regexp-in-string "\n" "\r\n" part)
             signature (mm-get-part signature)
@@ -908,16 +864,12 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
       (condition-case error
           (setq plain (epg-verify-string context signature part))
         (error
-         (mm-set-handle-multipart-parameter
-          mm-security-handle 'gnus-info "Failed")
+         (mm-sec-error 'gnus-info "Failed")
          (if (eq (car error) 'quit)
-             (mm-set-handle-multipart-parameter
-              mm-security-handle 'gnus-details "Quit.")
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details (mml2015-format-error error)))
+             (mm-sec-status 'gnus-details "Quit.")
+           (mm-sec-status 'gnus-details (mml2015-format-error error)))
          (throw 'error handle)))
-      (mm-set-handle-multipart-parameter
-       mm-security-handle 'gnus-info
+      (mm-sec-status 'gnus-info
        (mml2015-epg-verify-result-to-string
         (epg-context-result-for context 'verify)))
       handle)))
@@ -931,17 +883,14 @@ If set, it overrides the setting of `mml2015-sign-with-sender'."
     (condition-case error
         (setq plain (epg-verify-string context signature))
       (error
-       (mm-set-handle-multipart-parameter
-        mm-security-handle 'gnus-info "Failed")
+       (mm-sec-error 'gnus-info "Failed")
        (if (eq (car error) 'quit)
-           (mm-set-handle-multipart-parameter
-            mm-security-handle 'gnus-details "Quit.")
-         (mm-set-handle-multipart-parameter
-          mm-security-handle 'gnus-details (mml2015-format-error error)))))
+           (mm-sec-status 'gnus-details "Quit.")
+         (mm-sec-status 'gnus-details (mml2015-format-error error)))))
     (if plain
         (progn
-          (mm-set-handle-multipart-parameter
-           mm-security-handle 'gnus-info
+          (mm-sec-status
+           'gnus-info
            (mml2015-epg-verify-result-to-string
             (epg-context-result-for context 'verify)))
           (delete-region (point-min) (point-max))