From 5d04dade21133e36042140f83fb8d9d52c746469 Mon Sep 17 00:00:00 2001
From: Mark Wooding <mdw@distorted.org.uk>
Date: Mon, 14 Oct 2019 00:56:07 +0100
Subject: [PATCH] algorithms.c: Set `hashsz', `tagsz', and `name' properties on
 MAC keys.

The generic MAC objects, and Poly1305.
---
 algorithms.c      | 34 ++++++++++++++++++++++++++++++++--
 t/t-algorithms.py | 21 ++++++++++++---------
 2 files changed, 44 insertions(+), 11 deletions(-)

diff --git a/algorithms.c b/algorithms.c
index 071894a..57a41d7 100644
--- a/algorithms.c
+++ b/algorithms.c
@@ -2309,6 +2309,22 @@ static const PyGetSetDef gcmac_pygetset[] = {
   { 0 }
 };
 
+static PyObject *gmget_name(PyObject *me, void *hunoz)
+  { return (TEXT_FROMSTR(GMAC_M(me)->ops->c->name)); }
+
+static PyObject *gmget_hashsz(PyObject *me, void *hunoz)
+  { return (PyInt_FromLong(GMAC_M(me)->ops->c->hashsz)); }
+#define gmget_tagsz gmget_hashsz
+
+static const PyGetSetDef gmac_pygetset[] = {
+#define GETSETNAME(op, name) gm##op##_##name
+  GET	(hashsz,	"M.hashsz -> MAC output size")
+  GET	(tagsz,		"M.tagsz -> MAC output size")
+  GET	(name,		"M.name -> name of this kind of MAC")
+#undef GETSETNAME
+  { 0 }
+};
+
 static const PyTypeObject gcmac_pytype_skel = {
   PyVarObject_HEAD_INIT(0, 0)		/* Header */
   "GCMAC",				/* @tp_name@ */
@@ -2392,7 +2408,7 @@ static const PyTypeObject gmac_pytype_skel = {
   0,					/* @tp_iternext@ */
   0,					/* @tp_methods@ */
   0,					/* @tp_members@ */
-  0,					/* @tp_getset@ */
+  PYGETSET(gmac),			/* @tp_getset@ */
   0,					/* @tp_base@ */
   0,					/* @tp_dict@ */
   0,					/* @tp_descr_get@ */
@@ -2632,6 +2648,20 @@ static const PyGetSetDef poly1305cls_pygetset[] = {
   { 0 }
 };
 
+static PyObject *poly1305get_name(PyObject *me, void *hunoz)
+  { RETURN_OBJ(((PyHeapTypeObject *)poly1305key_pytype)->ht_name); }
+
+static PyObject *poly1305get_tagsz(PyObject *me, void *hunoz)
+  { return (PyInt_FromLong(16)); }
+
+static const PyGetSetDef poly1305_pygetset[] = {
+#define GETSETNAME(op, name) poly1305##op##_##name
+  GET	(tagsz,		"PK.tagsz -> MAC output size")
+  GET	(name,		"PK.name -> name of this kind of MAC")
+#undef GETSETNAME
+  { 0 }
+};
+
 static const PyMethodDef poly1305hash_pymethods[] = {
 #define METHNAME(name) polymeth_##name
   NAMETH(copy,		"P.copy() -> PP")
@@ -2734,7 +2764,7 @@ static const PyTypeObject poly1305key_pytype_skel = {
   0,					/* @tp_iternext@ */
   0,					/* @tp_methods@ */
   0,					/* @tp_members@ */
-  0,					/* @tp_getset@ */
+  PYGETSET(poly1305),			/* @tp_getset@ */
   0,					/* @tp_base@ */
   0,					/* @tp_dict@ */
   0,					/* @tp_descr_get@ */
diff --git a/t/t-algorithms.py b/t/t-algorithms.py
index 52decd6..aa8567b 100644
--- a/t/t-algorithms.py
+++ b/t/t-algorithms.py
@@ -602,29 +602,28 @@ class BaseTestHash (HashBufferTestMixin):
     """
     Check hash class HCLS.
 
-    If NEED_BUFSZ is false, then don't insist that HCLS have working `bufsz',
-    `name', or `hashsz' attributes.  This test is mostly reused for MACs,
-    which don't have these attributes.
+    If NEED_BUFSZ is false, then don't insist that HCLS has a working `bufsz'
+    attribute.  This test is mostly reused for MACs, which don't have this
+    attribute.
     """
     ## Check the class properties.
-    if need_bufsz:
-      me.assertEqual(type(hcls.name), str)
-      me.assertEqual(type(hcls.bufsz), int)
-      me.assertEqual(type(hcls.hashsz), int)
+    me.assertEqual(type(hcls.name), str)
+    if need_bufsz: me.assertEqual(type(hcls.bufsz), int)
+    me.assertEqual(type(hcls.hashsz), int)
 
     ## Set some initial values.
     m = T.span(131)
     h = hcls().hash(m).done()
 
     ## Check that hash length comes out right.
-    if need_bufsz: me.assertEqual(len(h), hcls.hashsz)
+    me.assertEqual(len(h), hcls.hashsz)
 
     ## Check that we get the same answer if we split the message up.
     me.assertEqual(h, hcls().hash(m[0:73]).hash(m[73:131]).done())
 
     ## Check the `check' method.
     me.assertTrue(hcls().hash(m).check(h))
-    me.assertFalse(hcls().hash(m).check(h ^ len(h)*C.bytes("aa")))
+    me.assertFalse(hcls().hash(m).check(h ^ hcls.hashsz*C.bytes("aa")))
 
     ## Check the menagerie of random hashing methods.
     def mkhash(_):
@@ -654,6 +653,7 @@ class TestMessageAuthentication (BaseTestHash, T.GenericTestMixin):
     ## Test hashing.
     k = T.span(mcls.keysz.default)
     key = mcls(k)
+    me.assertEqual(key.hashsz, key.tagsz)
     me.check_hash(key, need_bufsz = False)
 
     ## Check that bad key lengths are rejected.
@@ -685,6 +685,9 @@ class TestPoly1305 (HashBufferTestMixin):
     t = key(u).hash(m).done()
 
     ## Check the key properties.
+    me.assertEqual(key.name, "poly1305")
+    me.assertEqual(key.tagsz, 16)
+    me.assertEqual(key.tagsz, 16)
     me.assertEqual(len(t), 16)
 
     ## Check that we get the same answer if we split the message up.
-- 
2.11.0