From ea6d5592f2964a17b14c1714bb06fe01918323b5 Mon Sep 17 00:00:00 2001
From: Berker Peksag <berker.peksag@gmail.com>
Date: Tue, 12 May 2015 17:13:56 +0300
Subject: [PATCH] Issue #23796: peak and read1 methods of BufferedReader now
 raise ValueError if they called on a closed object.

Patch by John Hergenroeder.
---
 Lib/test/test_io.py      | 8 ++++++++
 Misc/NEWS                | 3 +++
 Modules/_io/bufferedio.c | 5 +++++
 3 files changed, 16 insertions(+)

diff --git a/Lib/test/test_io.py b/Lib/test/test_io.py
index 2fb1b1e24a1..416c547334e 100644
--- a/Lib/test/test_io.py
+++ b/Lib/test/test_io.py
@@ -1115,6 +1115,14 @@ class BufferedReaderTest(unittest.TestCase, CommonBufferedTests):
             self.assertEqual(rawio._extraneous_reads, 0,
                              "failed for {}: {} != 0".format(n, rawio._extraneous_reads))
 
+    def test_read_on_closed(self):
+        # Issue #23796
+        b = io.BufferedReader(io.BytesIO(b"12"))
+        b.read(1)
+        b.close()
+        self.assertRaises(ValueError, b.peek)
+        self.assertRaises(ValueError, b.read1, 1)
+
 
 class CBufferedReaderTest(BufferedReaderTest, SizeofTest):
     tp = io.BufferedReader
diff --git a/Misc/NEWS b/Misc/NEWS
index bc57613e9f7..7701261c49d 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -45,6 +45,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #23796: peak and read1 methods of BufferedReader now raise ValueError
+  if they called on a closed object. Patch by John Hergenroeder.
+
 - Issue #24134: assertRaises(), assertRaisesRegex(), assertWarns() and
   assertWarnsRegex() checks are not longer successful if the callable is None.
 
diff --git a/Modules/_io/bufferedio.c b/Modules/_io/bufferedio.c
index 3606cc8fe09..365bb85c74f 100644
--- a/Modules/_io/bufferedio.c
+++ b/Modules/_io/bufferedio.c
@@ -889,6 +889,8 @@ buffered_peek(buffered *self, PyObject *args)
     PyObject *res = NULL;
 
     CHECK_INITIALIZED(self)
+    CHECK_CLOSED(self, "peek of closed file")
+
     if (!PyArg_ParseTuple(args, "|n:peek", &n)) {
         return NULL;
     }
@@ -963,6 +965,9 @@ buffered_read1(buffered *self, PyObject *args)
                         "read length must be positive");
         return NULL;
     }
+
+    CHECK_CLOSED(self, "read of closed file")
+
     if (n == 0)
         return PyBytes_FromStringAndSize(NULL, 0);