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gh-111178: fix UBSan failures in Python/context.c #128242

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Merged
merged 4 commits into from
Jan 8, 2025
Merged

gh-111178: fix UBSan failures in Python/context.c #128242

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d9b1042
fix UBSan failures for `PyContext`
picnixz Dec 23, 2024
c9f8a06
fix UBSan failures for `PyContextVar`
picnixz Dec 23, 2024
e63ca99
fix UBSan failures for `PyContextToken`
picnixz Dec 23, 2024
637335d
fix UBSan failures for `_PyContextTokenMissing`
picnixz Dec 23, 2024
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121 changes: 68 additions & 53 deletions Python/context.c
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Original file line number Diff line number Diff line change
Expand Up @@ -419,6 +419,9 @@ class _contextvars.Context "PyContext *" "&PyContext_Type"
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=bdf87f8e0cb580e8]*/


#define _PyContext_CAST(op) ((PyContext *)(op))


static inline PyContext *
_context_alloc(void)
{
Expand Down Expand Up @@ -513,37 +516,40 @@ context_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
}

static int
context_tp_clear(PyContext *self)
context_tp_clear(PyObject *op)
{
PyContext *self = _PyContext_CAST(op);
Py_CLEAR(self->ctx_prev);
Py_CLEAR(self->ctx_vars);
return 0;
}

static int
context_tp_traverse(PyContext *self, visitproc visit, void *arg)
context_tp_traverse(PyObject *op, visitproc visit, void *arg)
{
PyContext *self = _PyContext_CAST(op);
Py_VISIT(self->ctx_prev);
Py_VISIT(self->ctx_vars);
return 0;
}

static void
context_tp_dealloc(PyContext *self)
context_tp_dealloc(PyObject *self)
{
_PyObject_GC_UNTRACK(self);

if (self->ctx_weakreflist != NULL) {
PyObject_ClearWeakRefs((PyObject*)self);
PyContext *ctx = _PyContext_CAST(self);
if (ctx->ctx_weakreflist != NULL) {
PyObject_ClearWeakRefs(self);
}
(void)context_tp_clear(self);

_Py_FREELIST_FREE(contexts, self, Py_TYPE(self)->tp_free);
}

static PyObject *
context_tp_iter(PyContext *self)
context_tp_iter(PyObject *op)
{
PyContext *self = _PyContext_CAST(op);
return _PyHamt_NewIterKeys(self->ctx_vars);
}

Expand Down Expand Up @@ -575,18 +581,20 @@ context_tp_richcompare(PyObject *v, PyObject *w, int op)
}

static Py_ssize_t
context_tp_len(PyContext *self)
context_tp_len(PyObject *op)
{
PyContext *self = _PyContext_CAST(op);
return _PyHamt_Len(self->ctx_vars);
}

static PyObject *
context_tp_subscript(PyContext *self, PyObject *key)
context_tp_subscript(PyObject *op, PyObject *key)
{
if (context_check_key_type(key)) {
return NULL;
}
PyObject *val = NULL;
PyContext *self = _PyContext_CAST(op);
int found = _PyHamt_Find(self->ctx_vars, key, &val);
if (found < 0) {
return NULL;
Expand All @@ -599,12 +607,13 @@ context_tp_subscript(PyContext *self, PyObject *key)
}

static int
context_tp_contains(PyContext *self, PyObject *key)
context_tp_contains(PyObject *op, PyObject *key)
{
if (context_check_key_type(key)) {
return -1;
}
PyObject *val = NULL;
PyContext *self = _PyContext_CAST(op);
return _PyHamt_Find(self->ctx_vars, key, &val);
}

Expand Down Expand Up @@ -701,7 +710,7 @@ _contextvars_Context_copy_impl(PyContext *self)


static PyObject *
context_run(PyContext *self, PyObject *const *args,
context_run(PyObject *self, PyObject *const *args,
Py_ssize_t nargs, PyObject *kwnames)
{
PyThreadState *ts = _PyThreadState_GET();
Expand All @@ -712,14 +721,14 @@ context_run(PyContext *self, PyObject *const *args,
return NULL;
}

if (_PyContext_Enter(ts, (PyObject *)self)) {
if (_PyContext_Enter(ts, self)) {
return NULL;
}

PyObject *call_result = _PyObject_VectorcallTstate(
ts, args[0], args + 1, nargs - 1, kwnames);

if (_PyContext_Exit(ts, (PyObject *)self)) {
if (_PyContext_Exit(ts, self)) {
Py_XDECREF(call_result);
return NULL;
}
Expand All @@ -739,21 +748,12 @@ static PyMethodDef PyContext_methods[] = {
};

static PySequenceMethods PyContext_as_sequence = {
0, /* sq_length */
0, /* sq_concat */
0, /* sq_repeat */
0, /* sq_item */
0, /* sq_slice */
0, /* sq_ass_item */
0, /* sq_ass_slice */
(objobjproc)context_tp_contains, /* sq_contains */
0, /* sq_inplace_concat */
0, /* sq_inplace_repeat */
.sq_contains = context_tp_contains
};

static PyMappingMethods PyContext_as_mapping = {
(lenfunc)context_tp_len, /* mp_length */
(binaryfunc)context_tp_subscript, /* mp_subscript */
.mp_length = context_tp_len,
.mp_subscript = context_tp_subscript
};

PyTypeObject PyContext_Type = {
Expand All @@ -763,13 +763,13 @@ PyTypeObject PyContext_Type = {
.tp_methods = PyContext_methods,
.tp_as_mapping = &PyContext_as_mapping,
.tp_as_sequence = &PyContext_as_sequence,
.tp_iter = (getiterfunc)context_tp_iter,
.tp_dealloc = (destructor)context_tp_dealloc,
.tp_iter = context_tp_iter,
.tp_dealloc = context_tp_dealloc,
.tp_getattro = PyObject_GenericGetAttr,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_richcompare = context_tp_richcompare,
.tp_traverse = (traverseproc)context_tp_traverse,
.tp_clear = (inquiry)context_tp_clear,
.tp_traverse = context_tp_traverse,
.tp_clear = context_tp_clear,
.tp_new = context_tp_new,
.tp_weaklistoffset = offsetof(PyContext, ctx_weakreflist),
.tp_hash = PyObject_HashNotImplemented,
Expand Down Expand Up @@ -909,6 +909,9 @@ class _contextvars.ContextVar "PyContextVar *" "&PyContextVar_Type"
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=445da935fa8883c3]*/


#define _PyContextVar_CAST(op) ((PyContextVar *)(op))


static PyObject *
contextvar_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
Expand All @@ -926,8 +929,9 @@ contextvar_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
}

static int
contextvar_tp_clear(PyContextVar *self)
contextvar_tp_clear(PyObject *op)
{
PyContextVar *self = _PyContextVar_CAST(op);
Py_CLEAR(self->var_name);
Py_CLEAR(self->var_default);
#ifndef Py_GIL_DISABLED
Expand All @@ -939,30 +943,33 @@ contextvar_tp_clear(PyContextVar *self)
}

static int
contextvar_tp_traverse(PyContextVar *self, visitproc visit, void *arg)
contextvar_tp_traverse(PyObject *op, visitproc visit, void *arg)
{
PyContextVar *self = _PyContextVar_CAST(op);
Py_VISIT(self->var_name);
Py_VISIT(self->var_default);
return 0;
}

static void
contextvar_tp_dealloc(PyContextVar *self)
contextvar_tp_dealloc(PyObject *self)
{
PyObject_GC_UnTrack(self);
(void)contextvar_tp_clear(self);
Py_TYPE(self)->tp_free(self);
}

static Py_hash_t
contextvar_tp_hash(PyContextVar *self)
contextvar_tp_hash(PyObject *op)
{
PyContextVar *self = _PyContextVar_CAST(op);
return self->var_hash;
}

static PyObject *
contextvar_tp_repr(PyContextVar *self)
contextvar_tp_repr(PyObject *op)
{
PyContextVar *self = _PyContextVar_CAST(op);
// Estimation based on the shortest name and default value,
// but maximize the pointer size.
// "<ContextVar name='a' at 0x1234567812345678>"
Expand Down Expand Up @@ -1106,15 +1113,15 @@ PyTypeObject PyContextVar_Type = {
sizeof(PyContextVar),
.tp_methods = PyContextVar_methods,
.tp_members = PyContextVar_members,
.tp_dealloc = (destructor)contextvar_tp_dealloc,
.tp_dealloc = contextvar_tp_dealloc,
.tp_getattro = PyObject_GenericGetAttr,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_traverse = (traverseproc)contextvar_tp_traverse,
.tp_clear = (inquiry)contextvar_tp_clear,
.tp_traverse = contextvar_tp_traverse,
.tp_clear = contextvar_tp_clear,
.tp_new = contextvar_tp_new,
.tp_free = PyObject_GC_Del,
.tp_hash = (hashfunc)contextvar_tp_hash,
.tp_repr = (reprfunc)contextvar_tp_repr,
.tp_hash = contextvar_tp_hash,
.tp_repr = contextvar_tp_repr,
};


Expand All @@ -1129,6 +1136,9 @@ class _contextvars.Token "PyContextToken *" "&PyContextToken_Type"
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=338a5e2db13d3f5b]*/


#define _PyContextToken_CAST(op) ((PyContextToken *)(op))


static PyObject *
token_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
{
Expand All @@ -1138,34 +1148,37 @@ token_tp_new(PyTypeObject *type, PyObject *args, PyObject *kwds)
}

static int
token_tp_clear(PyContextToken *self)
token_tp_clear(PyObject *op)
{
PyContextToken *self = _PyContextToken_CAST(op);
Py_CLEAR(self->tok_ctx);
Py_CLEAR(self->tok_var);
Py_CLEAR(self->tok_oldval);
return 0;
}

static int
token_tp_traverse(PyContextToken *self, visitproc visit, void *arg)
token_tp_traverse(PyObject *op, visitproc visit, void *arg)
{
PyContextToken *self = _PyContextToken_CAST(op);
Py_VISIT(self->tok_ctx);
Py_VISIT(self->tok_var);
Py_VISIT(self->tok_oldval);
return 0;
}

static void
token_tp_dealloc(PyContextToken *self)
token_tp_dealloc(PyObject *self)
{
PyObject_GC_UnTrack(self);
(void)token_tp_clear(self);
Py_TYPE(self)->tp_free(self);
}

static PyObject *
token_tp_repr(PyContextToken *self)
token_tp_repr(PyObject *op)
{
PyContextToken *self = _PyContextToken_CAST(op);
PyUnicodeWriter *writer = PyUnicodeWriter_Create(0);
if (writer == NULL) {
return NULL;
Expand Down Expand Up @@ -1195,14 +1208,16 @@ token_tp_repr(PyContextToken *self)
}

static PyObject *
token_get_var(PyContextToken *self, void *Py_UNUSED(ignored))
token_get_var(PyObject *op, void *Py_UNUSED(ignored))
{
PyContextToken *self = _PyContextToken_CAST(op);
return Py_NewRef(self->tok_var);;
}

static PyObject *
token_get_old_value(PyContextToken *self, void *Py_UNUSED(ignored))
token_get_old_value(PyObject *op, void *Py_UNUSED(ignored))
{
PyContextToken *self = _PyContextToken_CAST(op);
if (self->tok_oldval == NULL) {
return get_token_missing();
}
Expand All @@ -1211,8 +1226,8 @@ token_get_old_value(PyContextToken *self, void *Py_UNUSED(ignored))
}

static PyGetSetDef PyContextTokenType_getsetlist[] = {
{"var", (getter)token_get_var, NULL, NULL},
{"old_value", (getter)token_get_old_value, NULL, NULL},
{"var", token_get_var, NULL, NULL},
{"old_value", token_get_old_value, NULL, NULL},
{NULL}
};

Expand All @@ -1228,15 +1243,15 @@ PyTypeObject PyContextToken_Type = {
sizeof(PyContextToken),
.tp_methods = PyContextTokenType_methods,
.tp_getset = PyContextTokenType_getsetlist,
.tp_dealloc = (destructor)token_tp_dealloc,
.tp_dealloc = token_tp_dealloc,
.tp_getattro = PyObject_GenericGetAttr,
.tp_flags = Py_TPFLAGS_DEFAULT | Py_TPFLAGS_HAVE_GC,
.tp_traverse = (traverseproc)token_tp_traverse,
.tp_clear = (inquiry)token_tp_clear,
.tp_traverse = token_tp_traverse,
.tp_clear = token_tp_clear,
.tp_new = token_tp_new,
.tp_free = PyObject_GC_Del,
.tp_hash = PyObject_HashNotImplemented,
.tp_repr = (reprfunc)token_tp_repr,
.tp_repr = token_tp_repr,
};

static PyContextToken *
Expand Down Expand Up @@ -1270,7 +1285,7 @@ context_token_missing_tp_repr(PyObject *self)
}

static void
context_token_missing_tp_dealloc(_PyContextTokenMissing *Py_UNUSED(self))
context_token_missing_tp_dealloc(PyObject *Py_UNUSED(self))
{
#ifdef Py_DEBUG
/* The singleton is statically allocated. */
Expand All @@ -1285,7 +1300,7 @@ PyTypeObject _PyContextTokenMissing_Type = {
PyVarObject_HEAD_INIT(&PyType_Type, 0)
"Token.MISSING",
sizeof(_PyContextTokenMissing),
.tp_dealloc = (destructor)context_token_missing_tp_dealloc,
.tp_dealloc = context_token_missing_tp_dealloc,
.tp_getattro = PyObject_GenericGetAttr,
.tp_flags = Py_TPFLAGS_DEFAULT,
.tp_repr = context_token_missing_tp_repr,
Expand Down
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