diff options
Diffstat (limited to 'Python/initconfig.c')
| -rw-r--r-- | Python/initconfig.c | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/Python/initconfig.c b/Python/initconfig.c index 0341e7baa2..0d2077a657 100644 --- a/Python/initconfig.c +++ b/Python/initconfig.c @@ -3,6 +3,7 @@ #include "pycore_getopt.h" // _PyOS_GetOpt() #include "pycore_initconfig.h" // _PyStatus_OK() #include "pycore_interp.h" // _PyInterpreterState.runtime +#include "pycore_long.h" // _PY_LONG_MAX_STR_DIGITS_THRESHOLD #include "pycore_pathconfig.h" // _Py_path_config #include "pycore_pyerrors.h" // _PyErr_Fetch() #include "pycore_pylifecycle.h" // _Py_PreInitializeFromConfig() @@ -95,6 +96,10 @@ static const char usage_3[] = "\ -X pycache_prefix=PATH: enable writing .pyc files to a parallel tree rooted at the\n\ given directory instead of to the code tree\n\ -X warn_default_encoding: enable opt-in EncodingWarning for 'encoding=None'\n\ + -X int_max_str_digits=number: limit the size of int<->str conversions.\n\ + This helps avoid denial of service attacks when parsing untrusted data.\n\ + The default is sys.int_info.default_max_str_digits. 0 disables.\n\ +\n\ --check-hash-based-pycs always|default|never:\n\ control how Python invalidates hash-based .pyc files\n\ "; @@ -120,6 +125,10 @@ static const char usage_6[] = " to seed the hashes of str and bytes objects. It can also be set to an\n" " integer in the range [0,4294967295] to get hash values with a\n" " predictable seed.\n" +"PYTHONINTMAXSTRDIGITS: limits the maximum digit characters in an int value\n" +" when converting from a string and when converting an int back to a str.\n" +" A value of 0 disables the limit. Conversions to or from bases 2, 4, 8,\n" +" 16, and 32 are never limited.\n" "PYTHONMALLOC: set the Python memory allocators and/or install debug hooks\n" " on Python memory allocators. Use PYTHONMALLOC=debug to install debug\n" " hooks.\n" @@ -721,6 +730,10 @@ _PyConfig_InitCompatConfig(PyConfig *config) #endif } +/* Excluded from public struct PyConfig for backporting reasons. */ +/* default to unconfigured, _PyLong_InitTypes() does the rest */ +int _Py_global_config_int_max_str_digits = -1; + static void config_init_defaults(PyConfig *config) @@ -1757,6 +1770,48 @@ config_init_tracemalloc(PyConfig *config) return _PyStatus_OK(); } +static PyStatus +config_init_int_max_str_digits(PyConfig *config) +{ + int maxdigits; + int valid = 0; + + const char *env = config_get_env(config, "PYTHONINTMAXSTRDIGITS"); + if (env) { + if (!_Py_str_to_int(env, &maxdigits)) { + valid = ((maxdigits == 0) || (maxdigits >= _PY_LONG_MAX_STR_DIGITS_THRESHOLD)); + } + if (!valid) { +#define STRINGIFY(VAL) _STRINGIFY(VAL) +#define _STRINGIFY(VAL) #VAL + return _PyStatus_ERR( + "PYTHONINTMAXSTRDIGITS: invalid limit; must be >= " + STRINGIFY(_PY_LONG_MAX_STR_DIGITS_THRESHOLD) + " or 0 for unlimited."); + } + _Py_global_config_int_max_str_digits = maxdigits; + } + + const wchar_t *xoption = config_get_xoption(config, L"int_max_str_digits"); + if (xoption) { + const wchar_t *sep = wcschr(xoption, L'='); + if (sep) { + if (!config_wstr_to_int(sep + 1, &maxdigits)) { + valid = ((maxdigits == 0) || (maxdigits >= _PY_LONG_MAX_STR_DIGITS_THRESHOLD)); + } + } + if (!valid) { + return _PyStatus_ERR( + "-X int_max_str_digits: invalid limit; must be >= " + STRINGIFY(_PY_LONG_MAX_STR_DIGITS_THRESHOLD) + " or 0 for unlimited."); +#undef _STRINGIFY +#undef STRINGIFY + } + _Py_global_config_int_max_str_digits = maxdigits; + } + return _PyStatus_OK(); +} static PyStatus config_init_pycache_prefix(PyConfig *config) @@ -1808,6 +1863,12 @@ config_read_complex_options(PyConfig *config) return status; } } + if (_Py_global_config_int_max_str_digits < 0) { + status = config_init_int_max_str_digits(config); + if (_PyStatus_EXCEPTION(status)) { + return status; + } + } if (config->pycache_prefix == NULL) { status = config_init_pycache_prefix(config); |