diff options
| -rw-r--r-- | Lib/test/test_random.py | 16 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Core and Builtins/2017-10-01-18-59-40.bpo-31478.owtqoO.rst | 2 | ||||
| -rw-r--r-- | Modules/_randommodule.c | 10 |
3 files changed, 26 insertions, 2 deletions
diff --git a/Lib/test/test_random.py b/Lib/test/test_random.py index 90d334a..d2a4f21 100644 --- a/Lib/test/test_random.py +++ b/Lib/test/test_random.py @@ -307,6 +307,22 @@ class SystemRandom_TestBasicOps(TestBasicOps): class MersenneTwister_TestBasicOps(TestBasicOps): gen = random.Random() + @test_support.cpython_only + def test_bug_31478(self): + # _random.Random.seed() should ignore the __abs__() method of a + # long/int subclass argument. + class BadInt(int): + def __abs__(self): + 1/0 + class BadLong(long): + def __abs__(self): + 1/0 + self.gen.seed(42) + expected_value = self.gen.random() + for seed_arg in [42L, BadInt(42), BadLong(42)]: + self.gen.seed(seed_arg) + self.assertEqual(self.gen.random(), expected_value) + def test_setstate_first_arg(self): self.assertRaises(ValueError, self.gen.setstate, (1, None, None)) diff --git a/Misc/NEWS.d/next/Core and Builtins/2017-10-01-18-59-40.bpo-31478.owtqoO.rst b/Misc/NEWS.d/next/Core and Builtins/2017-10-01-18-59-40.bpo-31478.owtqoO.rst new file mode 100644 index 0000000..b5b32d6 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2017-10-01-18-59-40.bpo-31478.owtqoO.rst @@ -0,0 +1,2 @@ +Prevent unwanted behavior in `_random.Random.seed()` in case the argument +has a bad ``__abs__()`` method. Patch by Oren Milman. diff --git a/Modules/_randommodule.c b/Modules/_randommodule.c index 852b810..2e49db6 100644 --- a/Modules/_randommodule.c +++ b/Modules/_randommodule.c @@ -230,9 +230,15 @@ random_seed(RandomObject *self, PyObject *args) } /* If the arg is an int or long, use its absolute value; else use * the absolute value of its hash code. + * Calling int.__abs__() or long.__abs__() prevents calling arg.__abs__(), + * which might return an invalid value. See issue #31478. */ - if (PyInt_Check(arg) || PyLong_Check(arg)) - n = PyNumber_Absolute(arg); + if (PyInt_Check(arg)) { + n = PyInt_Type.tp_as_number->nb_absolute(arg); + } + else if (PyLong_Check(arg)) { + n = PyLong_Type.tp_as_number->nb_absolute(arg); + } else { long hash = PyObject_Hash(arg); if (hash == -1) |