Counter: Deprecate disable_shortcut; Remove __PCT_CTR_SHORTCUT__ entirely

The `disable_shortcut` option served as a workaround in case
`__PCT_CTR_SHORTCUT__` leaked through a wrapper object, but I don't
think anyone actually used it, and it was a bad idea to expose it as
part of the public API.

Now that we do strong type checking inside block_template.c, there
shoujld be no need to ever use this option.  It's now a no-op, retained
for backward compatibility only.  It will be removed in some future
version of PyCrypto.

3 files changed, 4 insertions, 22 deletions

diff --git a/src/_counter.c b/src/_counter.c
index c1f1e5f..729fc9e 100644
--- a/src/_counter.c
+++ b/src/_counter.c
@@ -42,11 +42,10 @@ CounterObject_init(PCT_CounterObject *self, PyObject *args, PyObject *kwargs)
 	PyStringObject *prefix=NULL, *suffix=NULL, *initval=NULL;
 #endif
     int allow_wraparound = 0;
-    int disable_shortcut = 0;
     Py_ssize_t size;
 
-    static char *kwlist[] = {"prefix", "suffix", "initval", "allow_wraparound", "disable_shortcut", NULL};
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "SSS|ii", kwlist, &prefix, &suffix, &initval, &allow_wraparound, &disable_shortcut))
+    static char *kwlist[] = {"prefix", "suffix", "initval", "allow_wraparound", NULL};
+    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "SSS|i", kwlist, &prefix, &suffix, &initval, &allow_wraparound))
         return -1;
 
     /* Check string size and set nbytes */
@@ -115,8 +114,7 @@ CounterObject_init(PCT_CounterObject *self, PyObject *args, PyObject *kwargs)
     memcpy(self->p, PyBytes_AS_STRING(initval), self->nbytes);
     memcpy(self->p + self->nbytes, PyBytes_AS_STRING(suffix), PyBytes_GET_SIZE(suffix));
 
-    /* Set shortcut_disabled and allow_wraparound */
-    self->shortcut_disabled = disable_shortcut;
+    /* Set allow_wraparound */
     self->allow_wraparound = allow_wraparound;
 
     /* Clear the carry flag */
@@ -322,14 +320,6 @@ CounterLEObject_getattr(PyObject *s, char *name)
     if (strcmp(name, "carry") == 0) {
 #endif
         return PyLong_FromLong((long)self->carry);
-#ifdef IS_PY3K
-    } else if (!self->shortcut_disabled && PyUnicode_CompareWithASCIIString(attr, "__PCT_CTR_SHORTCUT__") == 0) {
-#else
-    } else if (!self->shortcut_disabled && strcmp(name, "__PCT_CTR_SHORTCUT__") == 0) {
-#endif
-        /* Shortcut hack - See block_template.c */
-        Py_INCREF(Py_True);
-        return Py_True;
     }
 #ifdef IS_PY3K
   generic:
@@ -356,14 +346,6 @@ CounterBEObject_getattr(PyObject *s, char *name)
     if (strcmp(name, "carry") == 0) {
 #endif
         return PyLong_FromLong((long)self->carry);
-#ifdef IS_PY3K
-    } else if (!self->shortcut_disabled && PyUnicode_CompareWithASCIIString(attr, "__PCT_CTR_SHORTCUT__") == 0) {
-#else
-    } else if (!self->shortcut_disabled && strcmp(name, "__PCT_CTR_SHORTCUT__") == 0) {
-#endif
-        /* Shortcut hack - See block_template.c */
-        Py_INCREF(Py_True);
-        return Py_True;
     }
 #ifdef IS_PY3K
   generic:
diff --git a/src/_counter.h b/src/_counter.h
index 32c320b..e08757a 100644
--- a/src/_counter.h
+++ b/src/_counter.h
@@ -35,7 +35,6 @@ typedef struct {
     uint8_t *p;         /* Pointer to the part of the buffer that we're allowed to update */
     uint16_t nbytes;    /* The number of bytes that from .p that are part of the counter */
     void (*inc_func)(void *);   /* Pointer to the counter increment function */
-    int shortcut_disabled;  /* This gets set to a non-zero value when the shortcut mechanism is disabled */
     int carry;         /* This gets set by Counter*Object_increment when the counter wraps around */
     int allow_wraparound;   /* When this is false, we raise OverflowError on next_value() or __call__() when the counter wraps around */
 } PCT_CounterObject;
diff --git a/src/block_template.c b/src/block_template.c
index 3e19eca..c655509 100644
--- a/src/block_template.c
+++ b/src/block_template.c
@@ -801,6 +801,7 @@ _MODULE_NAME (void)
 	PyModule_AddIntConstant(m, "block_size", BLOCK_SIZE);
 	PyModule_AddIntConstant(m, "key_size", KEY_SIZE);
 
+	/* Import CounterBE and CounterLE from the _counter module */
 	Py_CLEAR(_counter_module);
 	_counter_module = PyImport_ImportModule("Crypto.Util._counter");
 	if (_counter_module) {