Convert OverflowError and OSError for invalid epoch-based datetime va…

…lues

cbor2/_decoder.py

@@ -545,7 +545,13 @@ def decode_datetime_string(self) -> datetime:
     def decode_epoch_datetime(self) -> datetime:
         # Semantic tag 1
         value = self._decode()
-        return self.set_shareable(datetime.fromtimestamp(value, timezone.utc))
+
+        try:
+            tmp = datetime.fromtimestamp(value, timezone.utc)
+        except (OverflowError, OSError) as exc:
+            raise CBORDecodeValueError("error decoding datetime from epoch") from exc
+
+        return self.set_shareable(tmp)
 
     def decode_positive_bignum(self) -> int:
         # Semantic tag 2

docs/versionhistory.rst

@@ -28,6 +28,8 @@ This library adheres to `Semantic Versioning <http://semver.org/>`_.
   ``CBORDecodeValueError``
 - Fixed ``TypeError`` from a failed decoding of ``MIMEMessage`` not being wrapped as
   ``CBORDecodeValueError``
+- Fixed ``OverflowError`` or ``OSError`` from a failed decoding of epoch-based ``datetime`` not
+  being wrapped as ``CBORDecodeValueError``
 
 **5.5.1** (2023-11-02)
 

source/decoder.c

@@ -1403,6 +1403,11 @@ CBORDecoder_decode_epoch_datetime(CBORDecoderObject *self)
             if (tuple) {
                 ret = PyDateTime_FromTimestamp(tuple);
                 Py_DECREF(tuple);
+                if (!ret && (
+                    PyErr_GivenExceptionMatches(PyErr_Occurred(), PyExc_OverflowError)
+                    || PyErr_GivenExceptionMatches(PyErr_Occurred(), PyExc_OSError)
+                ))
+                    raise_from(_CBOR2_CBORDecodeValueError, "error decoding datetime from epoch");
             }
         } else {
             PyErr_Format(

tests/test_decoder.py

@@ -472,6 +472,20 @@ def test_bad_datetime(impl):
     assert str(excinfo.value) == "invalid datetime string: '0000-123-01'"
 
 
+def test_datetime_overflow(impl):
+    with pytest.raises(impl.CBORDecodeError) as excinfo:
+        impl.loads(unhexlify("c11b9b9b9b0000000000"))
+
+    assert isinstance(excinfo.value.__cause__, OverflowError)
+
+
+def test_datetime_value_too_large(impl):
+    with pytest.raises(impl.CBORDecodeError) as excinfo:
+        impl.loads(unhexlify("c11b1616161616161616161616161616"))
+
+    assert isinstance(excinfo.value.__cause__, OSError)
+
+
 def test_datetime_timezone(impl):
     decoded = impl.loads(b"\xc0\x78\x192018-08-02T07:00:59+00:30")
     assert decoded == datetime(2018, 8, 2, 7, 0, 59, tzinfo=timezone(timedelta(minutes=30)))