bpo-9216: Add usedforsecurity to hashlib constructors (GH-16044)

The usedforsecurity keyword only argument added to the hash constructors is useful for FIPS builds and similar restrictive environment with non-technical requirements that legacy algorithms be forbidden by their implementations without being explicitly annotated as not being used for any security related purposes.  Linux distros with FIPS support benefit from this being standard rather than making up their own way(s) to do it.

Contributed and Signed-off-by: Christian Heimes christian@python.org

Modules/md5module.c

@@ -503,13 +503,15 @@ static PyTypeObject MD5type = {
 _md5.md5
 
     string: object(c_default="NULL") = b''
+    *
+    usedforsecurity: bool = True
 
 Return a new MD5 hash object; optionally initialized with a string.
 [clinic start generated code]*/
 
 static PyObject *
-_md5_md5_impl(PyObject *module, PyObject *string)
-/*[clinic end generated code: output=2cfd0f8c091b97e6 input=d12ef8f72d684f7b]*/
+_md5_md5_impl(PyObject *module, PyObject *string, int usedforsecurity)
+/*[clinic end generated code: output=587071f76254a4ac input=7a144a1905636985]*/
 {
     MD5object *new;
     Py_buffer buf;