Issue #23804: Fix SSL zero-length recv() calls to not block and raise EOF

diff --git a/Lib/test/test_ssl.py b/Lib/test/test_ssl.py
index 659d0dfa9503c1a8df8ffc6389ae6ebe3bec12e2..29922e7a0cac93b871bb92fd3121b314320cf973 100644 (file)
--- a/Lib/test/test_ssl.py
+++ b/Lib/test/test_ssl.py
@@ -2622,20 +2622,13 @@ else:
                         # consume data
                         s.read()
 
-                data = b"data"
-
                 # read(-1, buffer) is supported, even though read(-1) is not
+                data = b"data"
                 s.send(data)
                 buffer = bytearray(len(data))
                 self.assertEqual(s.read(-1, buffer), len(data))
                 self.assertEqual(buffer, data)
 
-                # recv/read(0) should return no data
-                s.send(data)
-                self.assertEqual(s.recv(0), b"")
-                self.assertEqual(s.read(0), b"")
-                self.assertEqual(s.read(), data)
-
                 s.write(b"over\n")
 
                 self.assertRaises(ValueError, s.recv, -1)
@@ -2643,6 +2636,26 @@ else:
 
                 s.close()
 
+        def test_recv_zero(self):
+            server = ThreadedEchoServer(CERTFILE)
+            server.__enter__()
+            self.addCleanup(server.__exit__, None, None)
+            s = socket.create_connection((HOST, server.port))
+            self.addCleanup(s.close)
+            s = ssl.wrap_socket(s, suppress_ragged_eofs=False)
+            self.addCleanup(s.close)
+
+            # recv/read(0) should return no data
+            s.send(b"data")
+            self.assertEqual(s.recv(0), b"")
+            self.assertEqual(s.read(0), b"")
+            self.assertEqual(s.read(), b"data")
+
+            # Should not block if the other end sends no data
+            s.setblocking(False)
+            self.assertEqual(s.recv(0), b"")
+            self.assertEqual(s.recv_into(bytearray()), 0)
+
         def test_handshake_timeout(self):
             # Issue #5103: SSL handshake must respect the socket timeout
             server = socket.socket(socket.AF_INET)

diff --git a/Misc/NEWS b/Misc/NEWS
index 9f5075c3897e1b3c6d2d41a6b04155bd506f231f..2622999016197b6c3dcdbf4ca0383eb89f1e6753 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -17,6 +17,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #23804: Fix SSL zero-length recv() calls to not block and not raise
+  an error about unclean EOF.
+
 - Issue #27466: Change time format returned by http.cookie.time2netscape,
   confirming the netscape cookie format and making it consistent with
   documentation.

diff --git a/Modules/_ssl.c b/Modules/_ssl.c
index def24c246b8eb93ce4766a4da67753b35744fa4b..4572751a851e8c7820bb5a528bb0bff9df7b2d96 100644 (file)
--- a/Modules/_ssl.c
+++ b/Modules/_ssl.c
@@ -1702,6 +1702,10 @@ static PyObject *PySSL_SSLread(PySSLSocket *self, PyObject *args)
         dest = PyBytes_FromStringAndSize(NULL, len);
         if (dest == NULL)
             goto error;
+        if (len == 0) {
+            Py_XDECREF(sock);
+            return dest;
+        }
         mem = PyBytes_AS_STRING(dest);
     }
     else {
@@ -1714,6 +1718,10 @@ static PyObject *PySSL_SSLread(PySSLSocket *self, PyObject *args)
                                 "maximum length can't fit in a C 'int'");
                 goto error;
             }
+            if (len == 0) {
+                count = 0;
+                goto done;
+            }
         }
     }