Close #17666: Fix reading gzip files with an extra field.

Lib/gzip.py

@@ -280,7 +280,8 @@ def _read_gzip_header(self):
 
         if flag & FEXTRA:
             # Read & discard the extra field, if present
-            self._read_exact(struct.unpack("<H", self._read_exact(2)))
+            extra_len, = struct.unpack("<H", self._read_exact(2))
+            self._read_exact(extra_len)
         if flag & FNAME:
             # Read and discard a null-terminated string containing the filename
             while True:

Lib/test/test_gzip.py

@@ -379,6 +379,13 @@ def test_read_truncated(self):
             with gzip.GzipFile(fileobj=io.BytesIO(truncated[:i])) as f:
                 self.assertRaises(EOFError, f.read, 1)
 
+    def test_read_with_extra(self):
+        # Gzip data with an extra field
+        gzdata = (b'\x1f\x8b\x08\x04\xb2\x17cQ\x02\xff'
+                  b'\x05\x00Extra'
+                  b'\x0bI-.\x01\x002\xd1Mx\x04\x00\x00\x00')
+        with gzip.GzipFile(fileobj=io.BytesIO(gzdata)) as f:
+            self.assertEqual(f.read(), b'Test')
 
 def test_main(verbose=None):
     support.run_unittest(TestGzip)

Misc/NEWS

@@ -2,6 +2,21 @@
 Python News
 +++++++++++
 
+What's New in Python 3.2.5?
+===========================
+
+*Release date: 13-May-2013*
+
+Library
+-------
+
+- Issue #17192: Restore the patch for Issue #11729 and Issue #10309
+  which were omitted in 3.2.4 when updating the bundled version of
+  libffi used by ctypes.
+
+- Issue #17666: Fix reading gzip files with an extra field.
+
+
 What's New in Python 3.2.4?
 ===========================
 
@@ -10,10 +25,6 @@ What's New in Python 3.2.4?
 Library
 -------
 
-- Issue #17192: Restore the patch for Issue #11729 and Issue #10309
-  which were ommitted in 3.2.4 when updating the bundled version of
-  libffi used by ctypes.
-
 - Issue #17625: In IDLE, close the replace dialog after it is used.