[3.10] bpo-46913: Fix test_ctypes, test_hashlib, test_faulthandler on UBSan (GH-31675)

* bpo-46913: Fix test_faulthandler.test_sigfpe() on UBSAN (GH-31662)

Disable undefined behavior sanitizer (UBSAN) on
faulthandler_sigfpe().

(cherry picked from commit 4173d677a1d7c72bb32d292fbff1b4cf073d615c)

* bpo-46913: Fix test_faulthandler.test_read_null() on UBSan (GH31672)

Disable undefined behavior sanitizer (UBSan) on
faulthandler._read_null().

(cherry picked from commit 65b92ccdec2ee4a99e54aaf7ae2d9bbc2ebfe549)

* bpo-46913: test_hashlib skips _sha3 tests on UBSan (GH-31673)

If Python is built with UBSan, test_hashlib skips tests on the _sha3
extension which currently has undefined behaviors.

This change allows to run test_hashlib to check for new UBSan regression,
but the known _sha3 undefined behavior must be fixed.

(cherry picked from commit 6d0d7d2b8c1e04fd51c6cb29cc09a41b60b97b7b)

* bpo-46913: Skip test_ctypes.test_shorts() on UBSan (GH-31674)

If Python is built with UBSan, test_ctypes now skips test_shorts().
This change allows to run test_ctypes to check for new UBSan regression,
but the known test_shorts() undefined behavior must be fixed.

(cherry picked from commit ad1b04451d3aca2c6fa6dbe2891676a4e0baac49)

1 files changed, 23 insertions, 3 deletions

diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index 350f4cf..e03f6d9 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -29,6 +29,23 @@
 
 #define PUTS(fd, str) _Py_write_noraise(fd, str, strlen(str))
 
+
+// clang uses __attribute__((no_sanitize("undefined")))
+// GCC 4.9+ uses __attribute__((no_sanitize_undefined))
+#if defined(__has_feature)  // Clang
+#  if __has_feature(undefined_behavior_sanitizer)
+#    define _Py_NO_SANITIZE_UNDEFINED __attribute__((no_sanitize("undefined")))
+#  endif
+#endif
+#if defined(__GNUC__) \
+    && ((__GNUC__ >= 5) || (__GNUC__ == 4) && (__GNUC_MINOR__ >= 9))
+#  define _Py_NO_SANITIZE_UNDEFINED __attribute__((no_sanitize_undefined))
+#endif
+#ifndef _Py_NO_SANITIZE_UNDEFINED
+#  define _Py_NO_SANITIZE_UNDEFINED
+#endif
+
+
 _Py_IDENTIFIER(enable);
 _Py_IDENTIFIER(fileno);
 _Py_IDENTIFIER(flush);
@@ -1014,7 +1031,7 @@ faulthandler_suppress_crash_report(void)
 #endif
 }
 
-static PyObject *
+static PyObject* _Py_NO_SANITIZE_UNDEFINED
 faulthandler_read_null(PyObject *self, PyObject *args)
 {
     volatile int *x;
@@ -1103,17 +1120,20 @@ faulthandler_fatal_error_c_thread(PyObject *self, PyObject *args)
     Py_RETURN_NONE;
 }
 
-static PyObject *
+static PyObject* _Py_NO_SANITIZE_UNDEFINED
 faulthandler_sigfpe(PyObject *self, PyObject *args)
 {
+    faulthandler_suppress_crash_report();
+
     /* Do an integer division by zero: raise a SIGFPE on Intel CPU, but not on
        PowerPC. Use volatile to disable compile-time optimizations. */
     volatile int x = 1, y = 0, z;
-    faulthandler_suppress_crash_report();
     z = x / y;
+
     /* If the division by zero didn't raise a SIGFPE (e.g. on PowerPC),
        raise it manually. */
     raise(SIGFPE);
+
     /* This line is never reached, but we pretend to make something with z
        to silence a compiler warning. */
     return PyLong_FromLong(z);