From 1514d1252f96e6a83eb65c439522a6b5443f6a1a Mon Sep 17 00:00:00 2001
From: "Jason R. Coombs" <jaraco@jaraco.com>
Date: Sun, 23 Jan 2022 10:17:41 -0500
Subject: [PATCH] [3.9] bpo-46474: Avoid REDoS in EntryPoint.pattern (sync with
 importlib_metadata 4.10.1) (GH-30803). (GH-30828)

(cherry picked from commit 51c3e28c8a163e58dc753765e3cc51d5a717e70d)

Co-authored-by: Jason R. Coombs <jaraco@jaraco.com>
---
 Lib/importlib/metadata.py                                     | 4 ++--
 .../next/Library/2022-01-22-14-49-10.bpo-46474.eKQhvx.rst     | 2 ++
 2 files changed, 4 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2022-01-22-14-49-10.bpo-46474.eKQhvx.rst

diff --git a/Lib/importlib/metadata.py b/Lib/importlib/metadata.py
index 594986ce23efab..7b8038fd63a847 100644
--- a/Lib/importlib/metadata.py
+++ b/Lib/importlib/metadata.py
@@ -49,8 +49,8 @@ class EntryPoint(
 
     pattern = re.compile(
         r'(?P<module>[\w.]+)\s*'
-        r'(:\s*(?P<attr>[\w.]+))?\s*'
-        r'(?P<extras>\[.*\])?\s*$'
+        r'(:\s*(?P<attr>[\w.]+)\s*)?'
+        r'((?P<extras>\[.*\])\s*)?$'
         )
     """
     A regular expression describing the syntax for an entry point,
diff --git a/Misc/NEWS.d/next/Library/2022-01-22-14-49-10.bpo-46474.eKQhvx.rst b/Misc/NEWS.d/next/Library/2022-01-22-14-49-10.bpo-46474.eKQhvx.rst
new file mode 100644
index 00000000000000..156b7de4f67877
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-01-22-14-49-10.bpo-46474.eKQhvx.rst
@@ -0,0 +1,2 @@
+In ``importlib.metadata.EntryPoint.pattern``, avoid potential REDoS by
+limiting ambiguity in consecutive whitespace.