From b837f218c9e8755fbc5e4a6d47a68c5fe8f7f81c Mon Sep 17 00:00:00 2001
From: Erica Portnoy <ebportnoy@gmail.com>
Date: Wed, 31 Oct 2018 17:59:24 -0700
Subject: [PATCH] U mode on open --> newline=None

---
 certbot/crypto_util.py | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/certbot/crypto_util.py b/certbot/crypto_util.py
index 942f8502f..7b558b060 100644
--- a/certbot/crypto_util.py
+++ b/certbot/crypto_util.py
@@ -458,8 +458,12 @@ def sha256sum(filename):
     :rtype: str
     """
     sha256 = hashlib.sha256()
-    with open(filename, 'rU') as file_d:
-        sha256.update(file_d.read().encode('UTF-8'))
+    if six.PY2:
+        with open(filename, 'rU') as file_d:
+            sha256.update(file_d.read().encode('UTF-8'))
+    else:
+        with open(filename, 'r', newline=None) as file_d:
+            sha256.update(file_d.read().encode('UTF-8'))
     return sha256.hexdigest()
 
 def cert_and_chain_from_fullchain(fullchain_pem):