69 lines
2.5 KiB
Diff
69 lines
2.5 KiB
Diff
From 518c864805dd93e62d59439e665a0ce9d6778419 Mon Sep 17 00:00:00 2001
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From: Ekin Dursun <ekindursun@gmail.com>
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Date: Thu, 10 Mar 2022 22:06:48 +0300
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Subject: [PATCH] mypyc: Fix overflow in id function (CPyTagged_Id)
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In CPython, the id of an object is its address. It's computed by
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converting the pointer to an unsigned integer (PyLong_FromVoidPtr). A
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similar logic is present here, pointer is converted to a Py_ssize_t and
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CPyTagged_FromSsize_t is called with that integer.
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There is a problem with that approach: Py_ssize_t cannot hold every
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pointer value. Sometimes overflow happens and CPyTagged_FromSsize_t is
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called with a negative integer.
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With the new approach, the number is checked: If it fits in a
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Py_ssize_t, CPyTagged_FromSsize_t is called. If not, it is directly
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converted to a PyObject using PyLong_FromVoidPtr.
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---
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mypyc/lib-rt/CPy.h | 1 +
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mypyc/lib-rt/int_ops.c | 9 +++++++++
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mypyc/lib-rt/misc_ops.c | 2 +-
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3 files changed, 11 insertions(+), 1 deletion(-)
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diff --git a/mypyc/lib-rt/CPy.h b/mypyc/lib-rt/CPy.h
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index 987819154ab..9f5ae52d4e4 100644
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--- a/mypyc/lib-rt/CPy.h
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+++ b/mypyc/lib-rt/CPy.h
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@@ -121,6 +121,7 @@ static inline size_t CPy_FindAttrOffset(PyTypeObject *trait, CPyVTableItem *vtab
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CPyTagged CPyTagged_FromSsize_t(Py_ssize_t value);
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+CPyTagged CPyTagged_FromVoidPtr(void *ptr);
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CPyTagged CPyTagged_FromObject(PyObject *object);
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CPyTagged CPyTagged_StealFromObject(PyObject *object);
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CPyTagged CPyTagged_BorrowFromObject(PyObject *object);
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diff --git a/mypyc/lib-rt/int_ops.c b/mypyc/lib-rt/int_ops.c
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index 1275f2c1057..edf06314161 100644
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--- a/mypyc/lib-rt/int_ops.c
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+++ b/mypyc/lib-rt/int_ops.c
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@@ -26,6 +26,15 @@ CPyTagged CPyTagged_FromSsize_t(Py_ssize_t value) {
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}
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}
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+CPyTagged CPyTagged_FromVoidPtr(void *ptr) {
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+ if ((uintptr_t)ptr > PY_SSIZE_T_MAX) {
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+ PyObject *object = PyLong_FromVoidPtr(ptr);
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+ return ((CPyTagged)object) | CPY_INT_TAG;
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+ } else {
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+ return CPyTagged_FromSsize_t((Py_ssize_t)ptr);
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+ }
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+}
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+
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CPyTagged CPyTagged_FromObject(PyObject *object) {
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int overflow;
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// The overflow check knows about CPyTagged's width
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diff --git a/mypyc/lib-rt/misc_ops.c b/mypyc/lib-rt/misc_ops.c
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index cebd1cf997f..dcce89d9072 100644
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--- a/mypyc/lib-rt/misc_ops.c
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+++ b/mypyc/lib-rt/misc_ops.c
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@@ -437,7 +437,7 @@ CPyPickle_GetState(PyObject *obj)
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}
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CPyTagged CPyTagged_Id(PyObject *o) {
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- return CPyTagged_FromSsize_t((Py_ssize_t)o);
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+ return CPyTagged_FromVoidPtr(o);
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}
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#define MAX_INT_CHARS 22
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