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v3.10.20
Modules/testcapi_long.h
207 строк
7 KB
Mark Dickinson
Issue #9530: Fix undefined behaviour due to signed overflow in testcapi_long.h.
19 ноя 2011, 21:58
19 ноя 2011, 21:58
b96172e
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/* Poor-man's template. Macros used: TESTNAME name of the test (like test_long_api_inner) TYPENAME the signed type (like long) F_S_TO_PY convert signed to pylong; TYPENAME -> PyObject* F_PY_TO_S convert pylong to signed; PyObject* -> TYPENAME F_U_TO_PY convert unsigned to pylong; unsigned TYPENAME -> PyObject* F_PY_TO_U convert pylong to unsigned; PyObject* -> unsigned TYPENAME */ static PyObject * TESTNAME(PyObject *error(const char*)) { const int NBITS = sizeof(TYPENAME) * 8; unsigned TYPENAME base; PyObject *pyresult; int i; /* Note: This test lets PyObjects leak if an error is raised. Since an error should never be raised, leaks are impossible <wink>. */ /* Test native -> PyLong -> native roundtrip identity. * Generate all powers of 2, and test them and their negations, * plus the numbers +-1 off from them. */ base = 1; for (i = 0; i < NBITS + 1; /* on last, base overflows to 0 */ ++i, base <<= 1) { int j; for (j = 0; j < 6; ++j) { TYPENAME in, out; unsigned TYPENAME uin, uout; /* For 0, 1, 2 use base; for 3, 4, 5 use -base */ uin = j < 3 ? base : 0U - base; /* For 0 & 3, subtract 1. * For 1 & 4, leave alone. * For 2 & 5, add 1. */ uin += (unsigned TYPENAME)(TYPENAME)(j % 3 - 1); pyresult = F_U_TO_PY(uin); if (pyresult == NULL) return error( "unsigned unexpected null result"); uout = F_PY_TO_U(pyresult); if (uout == (unsigned TYPENAME)-1 && PyErr_Occurred()) return error( "unsigned unexpected -1 result"); if (uout != uin) return error( "unsigned output != input"); UNBIND(pyresult); in = (TYPENAME)uin; pyresult = F_S_TO_PY(in); if (pyresult == NULL) return error( "signed unexpected null result"); out = F_PY_TO_S(pyresult); if (out == (TYPENAME)-1 && PyErr_Occurred()) return error( "signed unexpected -1 result"); if (out != in) return error( "signed output != input"); UNBIND(pyresult); } } /* Overflow tests. The loop above ensured that all limit cases that * should not overflow don't overflow, so all we need to do here is * provoke one-over-the-limit cases (not exhaustive, but sharp). */ { PyObject *one, *x, *y; TYPENAME out; unsigned TYPENAME uout; one = PyLong_FromLong(1); if (one == NULL) return error( "unexpected NULL from PyLong_FromLong"); /* Unsigned complains about -1? */ x = PyNumber_Negative(one); if (x == NULL) return error( "unexpected NULL from PyNumber_Negative"); uout = F_PY_TO_U(x); if (uout != (unsigned TYPENAME)-1 || !PyErr_Occurred()) return error( "PyLong_AsUnsignedXXX(-1) didn't complain"); if (!PyErr_ExceptionMatches(PyExc_OverflowError)) return error( "PyLong_AsUnsignedXXX(-1) raised " "something other than OverflowError"); PyErr_Clear(); UNBIND(x); /* Unsigned complains about 2**NBITS? */ y = PyLong_FromLong((long)NBITS); if (y == NULL) return error( "unexpected NULL from PyLong_FromLong"); x = PyNumber_Lshift(one, y); /* 1L << NBITS, == 2**NBITS */ UNBIND(y); if (x == NULL) return error( "unexpected NULL from PyNumber_Lshift"); uout = F_PY_TO_U(x); if (uout != (unsigned TYPENAME)-1 || !PyErr_Occurred()) return error( "PyLong_AsUnsignedXXX(2**NBITS) didn't " "complain"); if (!PyErr_ExceptionMatches(PyExc_OverflowError)) return error( "PyLong_AsUnsignedXXX(2**NBITS) raised " "something other than OverflowError"); PyErr_Clear(); /* Signed complains about 2**(NBITS-1)? x still has 2**NBITS. */ y = PyNumber_Rshift(x, one); /* 2**(NBITS-1) */ UNBIND(x); if (y == NULL) return error( "unexpected NULL from PyNumber_Rshift"); out = F_PY_TO_S(y); if (out != (TYPENAME)-1 || !PyErr_Occurred()) return error( "PyLong_AsXXX(2**(NBITS-1)) didn't " "complain"); if (!PyErr_ExceptionMatches(PyExc_OverflowError)) return error( "PyLong_AsXXX(2**(NBITS-1)) raised " "something other than OverflowError"); PyErr_Clear(); /* Signed complains about -2**(NBITS-1)-1?; y still has 2**(NBITS-1). */ x = PyNumber_Negative(y); /* -(2**(NBITS-1)) */ UNBIND(y); if (x == NULL) return error( "unexpected NULL from PyNumber_Negative"); y = PyNumber_Subtract(x, one); /* -(2**(NBITS-1))-1 */ UNBIND(x); if (y == NULL) return error( "unexpected NULL from PyNumber_Subtract"); out = F_PY_TO_S(y); if (out != (TYPENAME)-1 || !PyErr_Occurred()) return error( "PyLong_AsXXX(-2**(NBITS-1)-1) didn't " "complain"); if (!PyErr_ExceptionMatches(PyExc_OverflowError)) return error( "PyLong_AsXXX(-2**(NBITS-1)-1) raised " "something other than OverflowError"); PyErr_Clear(); UNBIND(y); Py_XDECREF(x); Py_XDECREF(y); Py_DECREF(one); } /* Test F_PY_TO_{S,U} on non-pylong input. This should raise a TypeError. */ { TYPENAME out; unsigned TYPENAME uout; Py_INCREF(Py_None); out = F_PY_TO_S(Py_None); if (out != (TYPENAME)-1 || !PyErr_Occurred()) return error("PyLong_AsXXX(None) didn't complain"); if (!PyErr_ExceptionMatches(PyExc_TypeError)) return error("PyLong_AsXXX(None) raised " "something other than TypeError"); PyErr_Clear(); uout = F_PY_TO_U(Py_None); if (uout != (unsigned TYPENAME)-1 || !PyErr_Occurred()) return error("PyLong_AsXXX(None) didn't complain"); if (!PyErr_ExceptionMatches(PyExc_TypeError)) return error("PyLong_AsXXX(None) raised " "something other than TypeError"); PyErr_Clear(); Py_DECREF(Py_None); } Py_INCREF(Py_None); return Py_None; }