From: Nadeem Vawda Date: Sun, 4 Nov 2012 23:38:48 +0000 (+0100) Subject: Issue #16350: Fix zlib decompressor handling of unused_data with multiple calls to... X-Git-Tag: v3.3.1rc1~678 X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=519f43844babca8bb23cfc2cd0ba9f5ee0b26034;p=python Issue #16350: Fix zlib decompressor handling of unused_data with multiple calls to decompress() after EOF. Patch by Serhiy Storchaka. --- 519f43844babca8bb23cfc2cd0ba9f5ee0b26034 diff --cc Lib/test/test_zlib.py index d637c2d685,c17b4d0b36..b6a60f4d68 --- a/Lib/test/test_zlib.py +++ b/Lib/test/test_zlib.py @@@ -467,26 -434,19 +467,40 @@@ class CompressObjectTestCase(BaseCompre y += dco.flush() self.assertEqual(y, b'foo') + def test_decompress_eof(self): + x = b'x\x9cK\xcb\xcf\x07\x00\x02\x82\x01E' # 'foo' + dco = zlib.decompressobj() + self.assertFalse(dco.eof) + dco.decompress(x[:-5]) + self.assertFalse(dco.eof) + dco.decompress(x[-5:]) + self.assertTrue(dco.eof) + dco.flush() + self.assertTrue(dco.eof) + + def test_decompress_eof_incomplete_stream(self): + x = b'x\x9cK\xcb\xcf\x07\x00\x02\x82\x01E' # 'foo' + dco = zlib.decompressobj() + self.assertFalse(dco.eof) + dco.decompress(x[:-5]) + self.assertFalse(dco.eof) + dco.flush() + self.assertFalse(dco.eof) + + def test_decompress_unused_data(self): + # Repeated calls to decompress() after EOF should accumulate data in + # dco.unused_data, instead of just storing the arg to the last call. + x = zlib.compress(HAMLET_SCENE) + HAMLET_SCENE + for step in 1, 2, 100: + dco = zlib.decompressobj() + data = b''.join(dco.decompress(x[i : i + step]) + for i in range(0, len(x), step)) + data += dco.flush() + ++ self.assertTrue(dco.eof) + self.assertEqual(data, HAMLET_SCENE) + self.assertEqual(dco.unused_data, HAMLET_SCENE) + if hasattr(zlib.compressobj(), "copy"): def test_compresscopy(self): # Test copying a compression object diff --cc Modules/zlibmodule.c index 6519194fb5,7734ba6dfa..888ef5388d --- a/Modules/zlibmodule.c +++ b/Modules/zlibmodule.c @@@ -693,14 -610,30 +693,31 @@@ PyZlib_objdecompress(compobject *self, preserved. */ if (err == Z_STREAM_END) { - Py_XDECREF(self->unused_data); /* Free original empty string */ - self->unused_data = PyBytes_FromStringAndSize( - (char *)self->zst.next_in, self->zst.avail_in); - if (self->unused_data == NULL) { - Py_DECREF(RetVal); - goto error; + if (self->zst.avail_in > 0) { + /* Append the leftover data to the existing value of unused_data. */ + Py_ssize_t old_size = PyBytes_GET_SIZE(self->unused_data); + Py_ssize_t new_size = old_size + self->zst.avail_in; + PyObject *new_data; + if (new_size <= old_size) { /* Check for overflow. */ + PyErr_NoMemory(); + Py_DECREF(RetVal); + RetVal = NULL; + goto error; + } + new_data = PyBytes_FromStringAndSize(NULL, new_size); + if (new_data == NULL) { + Py_DECREF(RetVal); + RetVal = NULL; + goto error; + } + Py_MEMCPY(PyBytes_AS_STRING(new_data), + PyBytes_AS_STRING(self->unused_data), old_size); + Py_MEMCPY(PyBytes_AS_STRING(new_data) + old_size, + self->zst.next_in, self->zst.avail_in); + Py_DECREF(self->unused_data); + self->unused_data = new_data; } + self->eof = 1; /* We will only get Z_BUF_ERROR if the output buffer was full but there wasn't more output when we tried again, so it is not an error condition.