[Python-checkins] Restrict co_code to be under INT_MAX in codeobject (GH-20628)
Ammar Askar
webhook-mailer at python.org
Wed Jun 10 19:31:31 EDT 2020
https://github.com/python/cpython/commit/3b3b83c965447a8329b34cb4befe6e9908880ee5
commit: 3b3b83c965447a8329b34cb4befe6e9908880ee5
branch: master
author: Ammar Askar <ammar at ammaraskar.com>
committer: GitHub <noreply at github.com>
date: 2020-06-11T00:31:22+01:00
summary:
Restrict co_code to be under INT_MAX in codeobject (GH-20628)
files:
M Objects/codeobject.c
M Objects/frameobject.c
diff --git a/Objects/codeobject.c b/Objects/codeobject.c
index 737635943aced..cb4fb68124333 100644
--- a/Objects/codeobject.c
+++ b/Objects/codeobject.c
@@ -166,6 +166,14 @@ PyCode_NewWithPosOnlyArgs(int argcount, int posonlyargcount, int kwonlyargcount,
return NULL;
}
+ /* Make sure that code is indexable with an int, this is
+ a long running assumption in ceval.c and many parts of
+ the interpreter. */
+ if (PyBytes_GET_SIZE(code) > INT_MAX) {
+ PyErr_SetString(PyExc_OverflowError, "co_code larger than INT_MAX");
+ return NULL;
+ }
+
/* Check for any inner or outer closure references */
n_cellvars = PyTuple_GET_SIZE(cellvars);
if (!n_cellvars && !PyTuple_GET_SIZE(freevars)) {
diff --git a/Objects/frameobject.c b/Objects/frameobject.c
index 0dad42ee7bff3..6e1cbcfaf6f51 100644
--- a/Objects/frameobject.c
+++ b/Objects/frameobject.c
@@ -397,9 +397,9 @@ frame_setlineno(PyFrameObject *f, PyObject* p_new_lineno, void *Py_UNUSED(ignore
return -1;
}
- int len = Py_SAFE_DOWNCAST(
- PyBytes_GET_SIZE(f->f_code->co_code)/sizeof(_Py_CODEUNIT),
- Py_ssize_t, int);
+ /* PyCode_NewWithPosOnlyArgs limits co_code to be under INT_MAX so this
+ * should never overflow. */
+ int len = (int)(PyBytes_GET_SIZE(f->f_code->co_code) / sizeof(_Py_CODEUNIT));
int *lines = marklines(f->f_code, len);
if (lines == NULL) {
return -1;
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