From 358e5e17a51ba00742bfaee4557a94c3c4179c22 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Fri, 15 Dec 2017 00:51:22 +0100 Subject: bpo-32329: Fix -R option for hash randomization (#4873) bpo-32329, bpo-32030: * The -R option now turns on hash randomization when the PYTHONHASHSEED environment variable is set to 0 Previously, the option was ignored. * sys.flags.hash_randomization is now properly set to 0 when hash randomization is turned off by PYTHONHASHSEED=0. * _PyCoreConfig_ReadEnv() now reads the PYTHONHASHSEED environment variable. _Py_HashRandomization_Init() now only apply the configuration, it doesn't read PYTHONHASHSEED anymore. --- Doc/using/cmdline.rst | 5 +-- Include/pylifecycle.h | 8 ++++- Lib/test/test_cmd_line.py | 12 +++++-- .../2017-12-15-00-13-04.bpo-32329.q47IN2.rst | 5 +++ Modules/main.c | 35 ++++++++++++++++---- Python/bootstrap_hash.c | 37 ++++++---------------- 6 files changed, 63 insertions(+), 39 deletions(-) create mode 100644 Misc/NEWS.d/next/Core and Builtins/2017-12-15-00-13-04.bpo-32329.q47IN2.rst diff --git a/Doc/using/cmdline.rst b/Doc/using/cmdline.rst index 5cb9071..598eb25 100644 --- a/Doc/using/cmdline.rst +++ b/Doc/using/cmdline.rst @@ -277,8 +277,9 @@ Miscellaneous options .. cmdoption:: -R - Kept for compatibility. On Python 3.3 and greater, hash randomization is - turned on by default. + Turn on hash randomization. This option only has an effect if the + :envvar:`PYTHONHASHSEED` environment variable is set to ``0``, since hash + randomization is enabled by default. On previous versions of Python, this option turns on hash randomization, so that the :meth:`__hash__` values of str, bytes and datetime diff --git a/Include/pylifecycle.h b/Include/pylifecycle.h index 61ed6cc..0416bfa 100644 --- a/Include/pylifecycle.h +++ b/Include/pylifecycle.h @@ -136,7 +136,13 @@ PyAPI_FUNC(_PyInitError) _PyImportHooks_Init(void); PyAPI_FUNC(int) _PyFrame_Init(void); PyAPI_FUNC(int) _PyFloat_Init(void); PyAPI_FUNC(int) PyByteArray_Init(void); -PyAPI_FUNC(_PyInitError) _Py_HashRandomization_Init(_PyCoreConfig *core_config); +PyAPI_FUNC(_PyInitError) _Py_HashRandomization_Init(const _PyCoreConfig *); +#endif +#ifdef Py_BUILD_CORE +PyAPI_FUNC(int) _Py_ReadHashSeed( + const char *seed_text, + int *use_hash_seed, + unsigned long *hash_seed); #endif /* Various internal finalizers */ diff --git a/Lib/test/test_cmd_line.py b/Lib/test/test_cmd_line.py index 2aff51b..2b14c30 100644 --- a/Lib/test/test_cmd_line.py +++ b/Lib/test/test_cmd_line.py @@ -432,8 +432,16 @@ class CmdLineTest(unittest.TestCase): # Verify that sys.flags contains hash_randomization code = 'import sys; print("random is", sys.flags.hash_randomization)' - rc, out, err = assert_python_ok('-c', code) - self.assertEqual(rc, 0) + rc, out, err = assert_python_ok('-c', code, PYTHONHASHSEED='') + self.assertIn(b'random is 1', out) + + rc, out, err = assert_python_ok('-c', code, PYTHONHASHSEED='random') + self.assertIn(b'random is 1', out) + + rc, out, err = assert_python_ok('-c', code, PYTHONHASHSEED='0') + self.assertIn(b'random is 0', out) + + rc, out, err = assert_python_ok('-R', '-c', code, PYTHONHASHSEED='0') self.assertIn(b'random is 1', out) def test_del___main__(self): diff --git a/Misc/NEWS.d/next/Core and Builtins/2017-12-15-00-13-04.bpo-32329.q47IN2.rst b/Misc/NEWS.d/next/Core and Builtins/2017-12-15-00-13-04.bpo-32329.q47IN2.rst new file mode 100644 index 0000000..86bcf23 --- /dev/null +++ b/Misc/NEWS.d/next/Core and Builtins/2017-12-15-00-13-04.bpo-32329.q47IN2.rst @@ -0,0 +1,5 @@ +The :option:`-R` option now turns on hash randomization when the +:envvar:`PYTHONHASHSEED` environment variable is set to ``0``. Previously, +the option was ignored. Moreover, ``sys.flags.hash_randomization`` is now +properly set to 0 when hash randomization is turned off by +``PYTHONHASHSEED=0``. diff --git a/Modules/main.c b/Modules/main.c index 6db7e5f..e1a2f98 100644 --- a/Modules/main.c +++ b/Modules/main.c @@ -726,7 +726,7 @@ pymain_parse_cmdline_impl(_PyMain *pymain) break; case 'R': - /* Ignored */ + pymain->core_config.use_hash_seed = 0; break; /* This space reserved for other options */ @@ -1293,6 +1293,10 @@ pymain_set_global_config(_PyMain *pymain) Py_IgnoreEnvironmentFlag = pymain->core_config.ignore_environment; Py_UTF8Mode = pymain->core_config.utf8_mode; + + /* Random or non-zero hash seed */ + Py_HashRandomizationFlag = (pymain->core_config.use_hash_seed == 0 || + pymain->core_config.hash_seed != 0); } @@ -1694,6 +1698,24 @@ config_init_home(_PyCoreConfig *config) } +static _PyInitError +config_init_hash_seed(_PyCoreConfig *config) +{ + if (config->use_hash_seed < 0) { + const char *seed_text = pymain_get_env_var("PYTHONHASHSEED"); + int use_hash_seed; + unsigned long hash_seed; + if (_Py_ReadHashSeed(seed_text, &use_hash_seed, &hash_seed) < 0) { + return _Py_INIT_USER_ERR("PYTHONHASHSEED must be \"random\" " + "or an integer in range [0; 4294967295]"); + } + config->use_hash_seed = use_hash_seed; + config->hash_seed = hash_seed; + } + return _Py_INIT_OK(); +} + + _PyInitError _PyCoreConfig_ReadEnv(_PyCoreConfig *config) { @@ -1712,6 +1734,11 @@ _PyCoreConfig_ReadEnv(_PyCoreConfig *config) return err; } + err = config_init_hash_seed(config); + if (_Py_INIT_FAILED(err)) { + return err; + } + return _Py_INIT_OK(); } @@ -1777,12 +1804,6 @@ pymain_parse_envvars(_PyMain *pymain) /* Get environment variables */ pymain_set_flags_from_env(pymain); - /* The variable is only tested for existence here; - _Py_HashRandomization_Init will check its value further. */ - if (pymain_get_env_var("PYTHONHASHSEED")) { - Py_HashRandomizationFlag = 1; - } - if (pymain_warnings_envvar(pymain) < 0) { return -1; } diff --git a/Python/bootstrap_hash.c b/Python/bootstrap_hash.c index 2762f46..9fd5cfb 100644 --- a/Python/bootstrap_hash.c +++ b/Python/bootstrap_hash.c @@ -533,9 +533,10 @@ _PyOS_URandomNonblock(void *buffer, Py_ssize_t size) return pyurandom(buffer, size, 0, 1); } -int Py_ReadHashSeed(const char *seed_text, - int *use_hash_seed, - unsigned long *hash_seed) +int +_Py_ReadHashSeed(const char *seed_text, + int *use_hash_seed, + unsigned long *hash_seed) { Py_BUILD_ASSERT(sizeof(_Py_HashSecret_t) == sizeof(_Py_HashSecret.uc)); /* Convert a text seed to a numeric one */ @@ -561,9 +562,9 @@ int Py_ReadHashSeed(const char *seed_text, return 0; } -static _PyInitError -init_hash_secret(int use_hash_seed, - unsigned long hash_seed) + +_PyInitError +_Py_HashRandomization_Init(const _PyCoreConfig *config) { void *secret = &_Py_HashSecret; Py_ssize_t secret_size = sizeof(_Py_HashSecret_t); @@ -573,14 +574,14 @@ init_hash_secret(int use_hash_seed, } _Py_HashSecret_Initialized = 1; - if (use_hash_seed) { - if (hash_seed == 0) { + if (config->use_hash_seed) { + if (config->hash_seed == 0) { /* disable the randomized hash */ memset(secret, 0, secret_size); } else { /* use the specified hash seed */ - lcg_urandom(hash_seed, secret, secret_size); + lcg_urandom(config->hash_seed, secret, secret_size); } } else { @@ -601,24 +602,6 @@ init_hash_secret(int use_hash_seed, return _Py_INIT_OK(); } -_PyInitError -_Py_HashRandomization_Init(_PyCoreConfig *core_config) -{ - const char *seed_text; - int use_hash_seed = core_config->use_hash_seed; - unsigned long hash_seed = core_config->hash_seed; - - if (use_hash_seed < 0) { - seed_text = Py_GETENV("PYTHONHASHSEED"); - if (Py_ReadHashSeed(seed_text, &use_hash_seed, &hash_seed) < 0) { - return _Py_INIT_USER_ERR("PYTHONHASHSEED must be \"random\" " - "or an integer in range [0; 4294967295]"); - } - core_config->use_hash_seed = use_hash_seed; - core_config->hash_seed = hash_seed; - } - return init_hash_secret(use_hash_seed, hash_seed); -} void _Py_HashRandomization_Fini(void) -- cgit v0.12