gh-111178: fix UBSan failures in Modules/_dbmmodule.c (#129775)

picnixz · web-flow · commit a1a6df282d73 · 2025-02-10T11:02:47.000+01:00
This fixes UBSan failures for `dbmobject`.

In addition, we perform some minor cleanup changes such as renaming
some `args` parameter to `dummy` in some `METH_NOARGS` methods and
suppressing an unused return value in `_dbm_module_free`.
diff --git a/Modules/_dbmmodule.c b/Modules/_dbmmodule.c
@@ -64,6 +64,8 @@ typedef struct {
     DBM *di_dbm;
 } dbmobject;
 
+#define dbmobject_CAST(op)  ((dbmobject *)(op))
+
 #include "clinic/_dbmmodule.c.h"
 
 #define check_dbmobject_open(v, err)                                \
@@ -94,15 +96,16 @@ newdbmobject(_dbm_state *state, const char *file, int flags, int mode)
 
 /* Methods */
 static int
-dbm_traverse(dbmobject *dp, visitproc visit, void *arg)
+dbm_traverse(PyObject *dp, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(dp));
     return 0;
 }
 
 static void
-dbm_dealloc(dbmobject *dp)
+dbm_dealloc(PyObject *self)
 {
+    dbmobject *dp = dbmobject_CAST(self);
     PyObject_GC_UnTrack(dp);
     if (dp->di_dbm) {
         dbm_close(dp->di_dbm);
@@ -113,8 +116,9 @@ dbm_dealloc(dbmobject *dp)
 }
 
 static Py_ssize_t
-dbm_length(dbmobject *dp)
+dbm_length(PyObject *self)
 {
+    dbmobject *dp = dbmobject_CAST(self);
     _dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
     assert(state != NULL);
     if (dp->di_dbm == NULL) {
@@ -135,8 +139,9 @@ dbm_length(dbmobject *dp)
 }
 
 static int
-dbm_bool(dbmobject *dp)
+dbm_bool(PyObject *self)
 {
+    dbmobject *dp = dbmobject_CAST(self);
     _dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
     assert(state != NULL);
 
@@ -166,10 +171,11 @@ dbm_bool(dbmobject *dp)
 }
 
 static PyObject *
-dbm_subscript(dbmobject *dp, PyObject *key)
+dbm_subscript(PyObject *self, PyObject *key)
 {
     datum drec, krec;
     Py_ssize_t tmp_size;
+    dbmobject *dp = dbmobject_CAST(self);
     _dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));
     assert(state != NULL);
     if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size)) {
@@ -192,10 +198,11 @@ dbm_subscript(dbmobject *dp, PyObject *key)
 }
 
 static int
-dbm_ass_sub(dbmobject *dp, PyObject *v, PyObject *w)
+dbm_ass_sub(PyObject *self, PyObject *v, PyObject *w)
 {
     datum krec, drec;
     Py_ssize_t tmp_size;
+    dbmobject *dp = dbmobject_CAST(self);
 
     if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {
         PyErr_SetString(PyExc_TypeError,
@@ -305,7 +312,7 @@ _dbm_dbm_keys_impl(dbmobject *self, PyTypeObject *cls)
 static int
 dbm_contains(PyObject *self, PyObject *arg)
 {
-    dbmobject *dp = (dbmobject *)self;
+    dbmobject *dp = dbmobject_CAST(self);
     datum key, val;
     Py_ssize_t size;
 
@@ -452,15 +459,16 @@ _dbm_dbm_clear_impl(dbmobject *self, PyTypeObject *cls)
 }
 
 static PyObject *
-dbm__enter__(PyObject *self, PyObject *args)
+dbm__enter__(PyObject *self, PyObject *Py_UNUSED(dummy))
 {
     return Py_NewRef(self);
 }
 
 static PyObject *
-dbm__exit__(PyObject *self, PyObject *args)
+dbm__exit__(PyObject *self, PyObject *Py_UNUSED(args))
 {
-    return _dbm_dbm_close_impl((dbmobject *)self);
+    dbmobject *dp = dbmobject_CAST(self);
+    return _dbm_dbm_close_impl(dp);
 }
 
 static PyMethodDef dbm_methods[] = {
@@ -610,7 +618,7 @@ _dbm_module_clear(PyObject *module)
 static void
 _dbm_module_free(void *module)
 {
-    _dbm_module_clear((PyObject *)module);
+    (void)_dbm_module_clear((PyObject *)module);
 }
 
 static PyModuleDef_Slot _dbmmodule_slots[] = {

Original file line number	Diff line number	Diff line change
`@@ -64,6 +64,8 @@ typedef struct {`
`64`	`64`	`DBM *di_dbm;`
`65`	`65`	`} dbmobject;`
`66`	`66`
	`67`	`+#define dbmobject_CAST(op) ((dbmobject *)(op))`
	`68`	`+`
`67`	`69`	`#include "clinic/_dbmmodule.c.h"`
`68`	`70`
`69`	`71`	`#define check_dbmobject_open(v, err) \`
`@@ -94,15 +96,16 @@ newdbmobject(_dbm_state state, const char file, int flags, int mode)`
`94`	`96`
`95`	`97`	`/* Methods */`
`96`	`98`	`static int`
`97`		`-dbm_traverse(dbmobject dp, visitproc visit, void arg)`
	`99`	`+dbm_traverse(PyObject dp, visitproc visit, void arg)`
`98`	`100`	`{`
`99`	`101`	`Py_VISIT(Py_TYPE(dp));`
`100`	`102`	`return 0;`
`101`	`103`	`}`
`102`	`104`
`103`	`105`	`static void`
`104`		`-dbm_dealloc(dbmobject *dp)`
	`106`	`+dbm_dealloc(PyObject *self)`
`105`	`107`	`{`
	`108`	`+ dbmobject *dp = dbmobject_CAST(self);`
`106`	`109`	`PyObject_GC_UnTrack(dp);`
`107`	`110`	`if (dp->di_dbm) {`
`108`	`111`	`dbm_close(dp->di_dbm);`
`@@ -113,8 +116,9 @@ dbm_dealloc(dbmobject *dp)`
`113`	`116`	`}`
`114`	`117`
`115`	`118`	`static Py_ssize_t`
`116`		`-dbm_length(dbmobject *dp)`
	`119`	`+dbm_length(PyObject *self)`
`117`	`120`	`{`
	`121`	`+ dbmobject *dp = dbmobject_CAST(self);`
`118`	`122`	`_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));`
`119`	`123`	`assert(state != NULL);`
`120`	`124`	`if (dp->di_dbm == NULL) {`
`@@ -135,8 +139,9 @@ dbm_length(dbmobject *dp)`
`135`	`139`	`}`
`136`	`140`
`137`	`141`	`static int`
`138`		`-dbm_bool(dbmobject *dp)`
	`142`	`+dbm_bool(PyObject *self)`
`139`	`143`	`{`
	`144`	`+ dbmobject *dp = dbmobject_CAST(self);`
`140`	`145`	`_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));`
`141`	`146`	`assert(state != NULL);`
`142`	`147`
`@@ -166,10 +171,11 @@ dbm_bool(dbmobject *dp)`
`166`	`171`	`}`
`167`	`172`
`168`	`173`	`static PyObject *`
`169`		`-dbm_subscript(dbmobject dp, PyObject key)`
	`174`	`+dbm_subscript(PyObject self, PyObject key)`
`170`	`175`	`{`
`171`	`176`	`datum drec, krec;`
`172`	`177`	`Py_ssize_t tmp_size;`
	`178`	`+ dbmobject *dp = dbmobject_CAST(self);`
`173`	`179`	`_dbm_state *state = PyType_GetModuleState(Py_TYPE(dp));`
`174`	`180`	`assert(state != NULL);`
`175`	`181`	`if (!PyArg_Parse(key, "s#", &krec.dptr, &tmp_size)) {`
`@@ -192,10 +198,11 @@ dbm_subscript(dbmobject dp, PyObject key)`
`192`	`198`	`}`
`193`	`199`
`194`	`200`	`static int`
`195`		`-dbm_ass_sub(dbmobject dp, PyObject v, PyObject *w)`
	`201`	`+dbm_ass_sub(PyObject self, PyObject v, PyObject *w)`
`196`	`202`	`{`
`197`	`203`	`datum krec, drec;`
`198`	`204`	`Py_ssize_t tmp_size;`
	`205`	`+ dbmobject *dp = dbmobject_CAST(self);`
`199`	`206`
`200`	`207`	`if ( !PyArg_Parse(v, "s#", &krec.dptr, &tmp_size) ) {`
`201`	`208`	`PyErr_SetString(PyExc_TypeError,`
`@@ -305,7 +312,7 @@ _dbm_dbm_keys_impl(dbmobject self, PyTypeObject cls)`
`305`	`312`	`static int`
`306`	`313`	`dbm_contains(PyObject self, PyObject arg)`
`307`	`314`	`{`
`308`		`- dbmobject dp = (dbmobject )self;`
	`315`	`+ dbmobject *dp = dbmobject_CAST(self);`
`309`	`316`	`datum key, val;`
`310`	`317`	`Py_ssize_t size;`
`311`	`318`
`@@ -452,15 +459,16 @@ _dbm_dbm_clear_impl(dbmobject self, PyTypeObject cls)`
`452`	`459`	`}`
`453`	`460`
`454`	`461`	`static PyObject *`
`455`		`-dbm__enter__(PyObject self, PyObject args)`
	`462`	`+dbm__enter__(PyObject self, PyObject Py_UNUSED(dummy))`
`456`	`463`	`{`
`457`	`464`	`return Py_NewRef(self);`
`458`	`465`	`}`
`459`	`466`
`460`	`467`	`static PyObject *`
`461`		`-dbm__exit__(PyObject self, PyObject args)`
	`468`	`+dbm__exit__(PyObject self, PyObject Py_UNUSED(args))`
`462`	`469`	`{`
`463`		`- return _dbm_dbm_close_impl((dbmobject *)self);`
	`470`	`+ dbmobject *dp = dbmobject_CAST(self);`
	`471`	`+ return _dbm_dbm_close_impl(dp);`
`464`	`472`	`}`
`465`	`473`
`466`	`474`	`static PyMethodDef dbm_methods[] = {`
`@@ -610,7 +618,7 @@ _dbm_module_clear(PyObject *module)`
`610`	`618`	`static void`
`611`	`619`	`_dbm_module_free(void *module)`
`612`	`620`	`{`
`613`		`- _dbm_module_clear((PyObject *)module);`
	`621`	`+ (void)_dbm_module_clear((PyObject *)module);`
`614`	`622`	`}`
`615`	`623`
`616`	`624`	`static PyModuleDef_Slot _dbmmodule_slots[] = {`