Issue #15633: httplib.HTTPResponse is now mark closed when the server sends less than the advertised Content-Length.

Lib/http/client.py

@@ -507,7 +507,11 @@ class HTTPResponse(io.RawIOBase):
             if self.length is None:
                 s = self.fp.read()
             else:
-                s = self._safe_read(self.length)
+                try:
+                    s = self._safe_read(self.length)
+                except IncompleteRead:
+                    self.close()
+                    raise
                 self.length = 0
             self.close()        # we read everything
             return s
@@ -532,13 +536,14 @@ class HTTPResponse(io.RawIOBase):
         # connection, and the user is reading more bytes than will be provided
         # (for example, reading in 1k chunks)
         n = self.fp.readinto(b)
-        if self.length is not None:
+        if not n:
+            # Ideally, we would raise IncompleteRead if the content-length
+            # wasn't satisfied, but it might break compatibility.
+            self.close()
+        elif self.length is not None:
             self.length -= n
             if not self.length:
                 self.close()
-        else:
-            if not n:
-                self.close()
         return n
 
     def _read_next_chunk_size(self):

Lib/test/test_httplib.py

@@ -235,6 +235,38 @@ class BasicTest(TestCase):
         self.assertEqual(n, 0)
         self.assertTrue(resp.isclosed())
 
+    def test_partial_reads_incomplete_body(self):
+        # if the server shuts down the connection before the whole
+        # content-length is delivered, the socket is gracefully closed
+        body = "HTTP/1.1 200 Ok\r\nContent-Length: 10\r\n\r\nText"
+        sock = FakeSocket(body)
+        resp = client.HTTPResponse(sock)
+        resp.begin()
+        self.assertEqual(resp.read(2), b'Te')
+        self.assertFalse(resp.isclosed())
+        self.assertEqual(resp.read(2), b'xt')
+        self.assertEqual(resp.read(1), b'')
+        self.assertTrue(resp.isclosed())
+
+    def test_partial_readintos_incomplete_body(self):
+        # if the server shuts down the connection before the whole
+        # content-length is delivered, the socket is gracefully closed
+        body = "HTTP/1.1 200 Ok\r\nContent-Length: 10\r\n\r\nText"
+        sock = FakeSocket(body)
+        resp = client.HTTPResponse(sock)
+        resp.begin()
+        b = bytearray(2)
+        n = resp.readinto(b)
+        self.assertEqual(n, 2)
+        self.assertEqual(bytes(b), b'Te')
+        self.assertFalse(resp.isclosed())
+        n = resp.readinto(b)
+        self.assertEqual(n, 2)
+        self.assertEqual(bytes(b), b'xt')
+        n = resp.readinto(b)
+        self.assertEqual(n, 0)
+        self.assertTrue(resp.isclosed())
+
     def test_host_port(self):
         # Check invalid host_port
 
@@ -488,7 +520,7 @@ class BasicTest(TestCase):
         resp = client.HTTPResponse(sock, method="GET")
         resp.begin()
         self.assertEqual(resp.read(), b'Hello\r\n')
-        resp.close()
+        self.assertTrue(resp.isclosed())
 
     def test_incomplete_read(self):
         sock = FakeSocket('HTTP/1.1 200 OK\r\nContent-Length: 10\r\n\r\nHello\r\n')
@@ -502,10 +534,9 @@ class BasicTest(TestCase):
                              "IncompleteRead(7 bytes read, 3 more expected)")
             self.assertEqual(str(i),
                              "IncompleteRead(7 bytes read, 3 more expected)")
+            self.assertTrue(resp.isclosed())
         else:
             self.fail('IncompleteRead expected')
-        finally:
-            resp.close()
 
     def test_epipe(self):
         sock = EPipeSocket(

Misc/NEWS

@@ -163,6 +163,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #15633: httplib.HTTPResponse is now mark closed when the server
+  sends less than the advertised Content-Length.
+
 - Issue #6972: The zipfile module no longer overwrites files outside of
   its destination path when extracting malicious zip files.