From 46da4c9d9367aaf4bd3ce2faf118845f3930dabf Mon Sep 17 00:00:00 2001
From: Daniel Watson <ozzloy@gmail.com>
Date: Sat, 3 Jun 2023 21:15:25 -0700
Subject: [PATCH] ; always CRLF before non-first boundary in multipart form
 data

; Insert CRLF after file contents and before boundary,
; in accordance with the syntax description here
; https://www.rfc-editor.org/rfc/rfc2046#section-5.1.1
; The CRLF is attached to the boundary, and not the preceding part.
---
 lisp/gnus/mm-url.el            |  3 +-
 test/lisp/gnus/mm-url-tests.el | 53 ++++++++++++++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)
 create mode 100644 test/lisp/gnus/mm-url-tests.el

diff --git a/lisp/gnus/mm-url.el b/lisp/gnus/mm-url.el
index 11847a79f17..022762a7799 100644
--- a/lisp/gnus/mm-url.el
+++ b/lisp/gnus/mm-url.el
@@ -438,8 +438,7 @@ mm-url-encode-multipart-form-data
 	  (insert (format "Content-Disposition: form-data; name=%S\r\n\r\n"
 			  name))
 	  (insert value)))
-	(unless (bolp)
-	  (insert "\r\n"))))
+	(insert "\r\n")))
     (insert "--" boundary "--\r\n")
     (buffer-string)))
 
diff --git a/test/lisp/gnus/mm-url-tests.el b/test/lisp/gnus/mm-url-tests.el
new file mode 100644
index 00000000000..ed51cb7d086
--- /dev/null
+++ b/test/lisp/gnus/mm-url-tests.el
@@ -0,0 +1,53 @@
+;;; mm-url-tests.el ---  -*- lexical-binding:t -*-
+
+;; Copyright (C) 2021-2023 Free Software Foundation, Inc.
+
+;; This file is part of GNU Emacs.
+
+;; GNU Emacs is free software: you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation, either version 3 of the License, or
+;; (at your option) any later version.
+
+;; GNU Emacs is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+
+;; You should have received a copy of the GNU General Public License
+;; along with GNU Emacs.  If not, see <https://www.gnu.org/licenses/>.
+
+;;; Commentary:
+
+;;; Code:
+
+(require 'ert)
+(require 'mm-url)
+
+(ert-deftest test-mm-url-encode-multipart-form-data ()
+  (letrec
+      ((boundary "====-=-=")
+       (make-data (lambda (count)
+                    `(("file"
+                       ("filedata" . ,(make-string count ?\n))
+                       ("name"     . "file")
+                       ("filename" . "g")))))
+       (template
+        (concat
+         "--" boundary "\r\n"
+         "Content-Disposition:"
+         " form-data; name=\"file\"; filename=\"g\"\r\n"
+         "Content-Transfer-Encoding: binary\r\n"
+         "Content-Type: text/plain\r\n"
+         "\r\n"
+         "%s" ;; here's the file content
+         "\r\n" ;; \r\n attaches to boundary below, not file content
+         ;; ref: https://www.rfc-editor.org/rfc/rfc2046#section-5.1.1
+         "--" boundary "--" "\r\n")))
+    (dotimes (count 3)
+      (let ((data (funcall make-data count))
+            (expected (format template (make-string count ?\n))))
+        (should (equal (mm-url-encode-multipart-form-data data boundary)
+                       expected))))))
+
+;;; mm-url-tests.el ends here
-- 
2.34.1