[Python-checkins] closes bpo-38124: Fix bounds check in PyState_AddModule. (GH-16007)
Benjamin Peterson
webhook-mailer at python.org
Wed Sep 11 19:43:26 EDT 2019
https://github.com/python/cpython/commit/39de95b746c990e6a2fe9af5fad01747f58b2e5f
commit: 39de95b746c990e6a2fe9af5fad01747f58b2e5f
branch: master
author: Benjamin Peterson <benjamin at python.org>
committer: GitHub <noreply at github.com>
date: 2019-09-12T00:43:22+01:00
summary:
closes bpo-38124: Fix bounds check in PyState_AddModule. (GH-16007)
The >=, checking whether a module index was in already in the module-by-index list, needed to be strict.
Also, fold nested ifs into one and fix some bad spacing.
files:
A Misc/NEWS.d/next/Core and Builtins/2019-09-12-00-14-01.bpo-38124.n6E0H7.rst
M Python/pystate.c
diff --git a/Misc/NEWS.d/next/Core and Builtins/2019-09-12-00-14-01.bpo-38124.n6E0H7.rst b/Misc/NEWS.d/next/Core and Builtins/2019-09-12-00-14-01.bpo-38124.n6E0H7.rst
new file mode 100644
index 000000000000..dca0ba5bc0cc
--- /dev/null
+++ b/Misc/NEWS.d/next/Core and Builtins/2019-09-12-00-14-01.bpo-38124.n6E0H7.rst
@@ -0,0 +1,2 @@
+Fix an off-by-one error in PyState_AddModule that could cause out-of-bounds
+memory access.
diff --git a/Python/pystate.c b/Python/pystate.c
index 02bc90394361..7dd8b7f866b5 100644
--- a/Python/pystate.c
+++ b/Python/pystate.c
@@ -684,7 +684,7 @@ _PyState_AddModule(PyObject* module, struct PyModuleDef* def)
if (!state->modules_by_index)
return -1;
}
- while(PyList_GET_SIZE(state->modules_by_index) <= def->m_base.m_index)
+ while (PyList_GET_SIZE(state->modules_by_index) <= def->m_base.m_index)
if (PyList_Append(state->modules_by_index, Py_None) < 0)
return -1;
Py_INCREF(module);
@@ -702,13 +702,11 @@ PyState_AddModule(PyObject* module, struct PyModuleDef* def)
return -1;
}
index = def->m_base.m_index;
- if (state->modules_by_index) {
- if(PyList_GET_SIZE(state->modules_by_index) >= index) {
- if(module == PyList_GET_ITEM(state->modules_by_index, index)) {
- Py_FatalError("PyState_AddModule: Module already added!");
- return -1;
- }
- }
+ if (state->modules_by_index &&
+ index < PyList_GET_SIZE(state->modules_by_index) &&
+ module == PyList_GET_ITEM(state->modules_by_index, index)) {
+ Py_FatalError("PyState_AddModule: Module already added!");
+ return -1;
}
return _PyState_AddModule(module, def);
}
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