master d11627a: Make gnus-base64-repad a bit stricter again

[Lars Ingebrigtsen]

branch: master
commit d11627a7cadfe7db9415269135a8f4bec543ccd7
Author: Alex Bochannek <alex@bochannek.com>
Commit: Lars Ingebrigtsen <larsi@gnus.org>

    Make gnus-base64-repad a bit stricter again
    
    * lisp/gnus/gnus-util.el (gnus-base64-repad): Make the code a bit
    stricter again.
---
 lisp/gnus/gnus-util.el            |  6 +++++-
 test/lisp/gnus/gnus-util-tests.el | 13 ++++++++-----
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/lisp/gnus/gnus-util.el b/lisp/gnus/gnus-util.el
index 0e15ebc..1cf6bb7 100644
--- a/lisp/gnus/gnus-util.el
+++ b/lisp/gnus/gnus-util.el
@@ -1368,7 +1368,11 @@ CRLF (RFC 5321 SMTP)."
   ;;   input (3.1, 3.3)
   ;; - if line-length is set, error on input exceeding the limit (3.1)
   ;; - reject characters outside base encoding (3.3, also section 12)
-  (let ((splitstr (split-string str "[\n\r \t]+" t)))
+  ;;
+  ;; RFC 5322 section 2.2.3 consideration:
+  ;; Because base 64-encoded strings can appear in long header fields, remove
+  ;; folding whitespace while still observing the RFC 4648 decisions above.
+  (let ((splitstr (split-string str "[ \t]*[\r\n]+[ \t]?" t)))
     (when (and reject-newlines (> (length splitstr) 1))
       (error "Invalid Base64 string"))
     (dolist (substr splitstr)
diff --git a/test/lisp/gnus/gnus-util-tests.el 
b/test/lisp/gnus/gnus-util-tests.el
index ec58032..47f0a9c 100644
--- a/test/lisp/gnus/gnus-util-tests.el
+++ b/test/lisp/gnus/gnus-util-tests.el
@@ -151,8 +151,10 @@
   (should (equal "Zg==" (gnus-base64-repad "Zg")))
   (should (equal "Zg==" (gnus-base64-repad "Zg====")))
 
-  (should (equal (gnus-base64-repad " ") ""))
-  (should (equal (gnus-base64-repad "Zg== ") "Zg=="))
+  (should-error (gnus-base64-repad " ")
+                :type 'error)
+  (should-error (gnus-base64-repad "Zg== ")
+                :type 'error)
   (should-error (gnus-base64-repad "Z?\x00g==")
                 :type 'error)
   ;; line-length
@@ -162,9 +164,10 @@
   (should-error (gnus-base64-repad "Zm9v\r\nYmFy" t)
                 :type 'error)
   (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9vYmFy" t)))
-  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v\r\nYmFy" nil)))
-  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v\r\nYmFy\n" nil)))
-  (should (equal (gnus-base64-repad "Zm9v\r\n YmFy\r\n" nil) "Zm9vYmFy"))
+  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v\r\nYmFy")))
+  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v\r\nYmFy\n")))
+  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v\r\n YmFy\r\n")))
+  (should (equal "Zm9vYmFy" (gnus-base64-repad "Zm9v \r\n\tYmFy")))
   (should-error (gnus-base64-repad "Zm9v\r\nYmFy" nil 3)
                 :type 'error))