File CVE-2021-3177-buf_ovrfl_PyCArg_repr.patch of Package python3.39454
From 34df10a9a16b38d54421eeeaf73ec89828563be7 Mon Sep 17 00:00:00 2001
From: Benjamin Peterson <benjamin@python.org>
Date: Mon, 18 Jan 2021 15:11:46 -0600
Subject: [PATCH] [3.6] closes bpo-42938: Replace snprintf with Python unicode
formatting in ctypes param reprs. (GH-24250)
(cherry picked from commit 916610ef90a0d0761f08747f7b0905541f0977c7)
Co-authored-by: Benjamin Peterson <benjamin@python.org>
---
Lib/ctypes/test/test_parameters.py | 43 ++++++
Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst | 2
Modules/_ctypes/callproc.c | 70 +++++-----
3 files changed, 83 insertions(+), 32 deletions(-)
create mode 100644 Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst
Index: Python-3.4.10/Lib/ctypes/test/test_parameters.py
===================================================================
--- Python-3.4.10.orig/Lib/ctypes/test/test_parameters.py 2019-03-18 17:51:26.000000000 +0100
+++ Python-3.4.10/Lib/ctypes/test/test_parameters.py 2025-07-03 21:36:35.010814189 +0200
@@ -170,6 +170,49 @@
self.assertRaises(ArgumentError, func, 99)
+ def test_parameter_repr(self):
+ from ctypes import (
+ c_bool,
+ c_char,
+ c_wchar,
+ c_byte,
+ c_ubyte,
+ c_short,
+ c_ushort,
+ c_int,
+ c_uint,
+ c_long,
+ c_ulong,
+ c_longlong,
+ c_ulonglong,
+ c_float,
+ c_double,
+ c_longdouble,
+ c_char_p,
+ c_wchar_p,
+ c_void_p,
+ )
+ self.assertRegex(repr(c_bool.from_param(True)), r"^<cparam '\?' at 0x[A-Fa-f0-9]+>$")
+ self.assertEqual(repr(c_char.from_param(97)), "<cparam 'c' ('a')>")
+ self.assertRegex(repr(c_wchar.from_param('a')), r"^<cparam 'u' at 0x[A-Fa-f0-9]+>$")
+ self.assertEqual(repr(c_byte.from_param(98)), "<cparam 'b' (98)>")
+ self.assertEqual(repr(c_ubyte.from_param(98)), "<cparam 'B' (98)>")
+ self.assertEqual(repr(c_short.from_param(511)), "<cparam 'h' (511)>")
+ self.assertEqual(repr(c_ushort.from_param(511)), "<cparam 'H' (511)>")
+ self.assertRegex(repr(c_int.from_param(20000)), r"^<cparam '[li]' \(20000\)>$")
+ self.assertRegex(repr(c_uint.from_param(20000)), r"^<cparam '[LI]' \(20000\)>$")
+ self.assertRegex(repr(c_long.from_param(20000)), r"^<cparam '[li]' \(20000\)>$")
+ self.assertRegex(repr(c_ulong.from_param(20000)), r"^<cparam '[LI]' \(20000\)>$")
+ self.assertRegex(repr(c_longlong.from_param(20000)), r"^<cparam '[liq]' \(20000\)>$")
+ self.assertRegex(repr(c_ulonglong.from_param(20000)), r"^<cparam '[LIQ]' \(20000\)>$")
+ self.assertEqual(repr(c_float.from_param(1.5)), "<cparam 'f' (1.5)>")
+ self.assertEqual(repr(c_double.from_param(1.5)), "<cparam 'd' (1.5)>")
+ self.assertEqual(repr(c_double.from_param(1e300)), "<cparam 'd' (1e+300)>")
+ self.assertRegex(repr(c_longdouble.from_param(1.5)), r"^<cparam ('d' \(1.5\)|'g' at 0x[A-Fa-f0-9]+)>$")
+ self.assertRegex(repr(c_char_p.from_param(b'hihi')), "^<cparam 'z' \(0x[A-Fa-f0-9]+\)>$")
+ self.assertRegex(repr(c_wchar_p.from_param('hihi')), "^<cparam 'Z' \(0x[A-Fa-f0-9]+\)>$")
+ self.assertRegex(repr(c_void_p.from_param(0x12)), r"^<cparam 'P' \(0x0*12\)>$")
+
################################################################
if __name__ == '__main__':
Index: Python-3.4.10/Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ Python-3.4.10/Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst 2025-07-03 21:36:35.011118700 +0200
@@ -0,0 +1,2 @@
+Avoid static buffers when computing the repr of :class:`ctypes.c_double` and
+:class:`ctypes.c_longdouble` values.
Index: Python-3.4.10/Modules/_ctypes/callproc.c
===================================================================
--- Python-3.4.10.orig/Modules/_ctypes/callproc.c 2019-03-18 17:51:26.000000000 +0100
+++ Python-3.4.10/Modules/_ctypes/callproc.c 2025-07-03 21:44:05.585811058 +0200
@@ -446,57 +446,60 @@
PyObject_Del(self);
}
+static int
+is_literal_char(unsigned char c)
+{
+ return c < 128 && _PyUnicode_IsPrintable(c) && c != '\\' && c != '\'';
+}
+
static PyObject *
PyCArg_repr(PyCArgObject *self)
{
- char buffer[256];
switch(self->tag) {
case 'b':
case 'B':
- sprintf(buffer, "<cparam '%c' (%d)>",
+ return PyUnicode_FromFormat("<cparam '%c' (%d)>",
self->tag, self->value.b);
- break;
case 'h':
case 'H':
- sprintf(buffer, "<cparam '%c' (%d)>",
+ return PyUnicode_FromFormat("<cparam '%c' (%d)>",
self->tag, self->value.h);
- break;
case 'i':
case 'I':
- sprintf(buffer, "<cparam '%c' (%d)>",
+ return PyUnicode_FromFormat("<cparam '%c' (%d)>",
self->tag, self->value.i);
- break;
case 'l':
case 'L':
- sprintf(buffer, "<cparam '%c' (%ld)>",
+ return PyUnicode_FromFormat("<cparam '%c' (%ld)>",
self->tag, self->value.l);
- break;
#ifdef HAVE_LONG_LONG
case 'q':
case 'Q':
- sprintf(buffer,
-#ifdef MS_WIN32
- "<cparam '%c' (%I64d)>",
-#else
- "<cparam '%c' (%qd)>",
-#endif
+ return PyUnicode_FromFormat("<cparam '%c' (%lld)>",
self->tag, self->value.q);
- break;
#endif
case 'd':
- sprintf(buffer, "<cparam '%c' (%f)>",
- self->tag, self->value.d);
- break;
- case 'f':
- sprintf(buffer, "<cparam '%c' (%f)>",
- self->tag, self->value.f);
- break;
-
+ case 'f': {
+ PyObject *f;
+ PyObject *result;
+ f = PyFloat_FromDouble((self->tag == 'f') ? self->value.f : self->value.d);
+ if (f == NULL) {
+ return NULL;
+ }
+ result = PyUnicode_FromFormat("<cparam '%c' (%R)>", self->tag, f);
+ Py_DECREF(f);
+ return result;
+ }
case 'c':
- sprintf(buffer, "<cparam '%c' (%c)>",
+ if (is_literal_char((unsigned char)self->value.c)) {
+ return PyUnicode_FromFormat("<cparam '%c' ('%c')>",
self->tag, self->value.c);
- break;
+ }
+ else {
+ return PyUnicode_FromFormat("<cparam '%c' ('\\x%02x')>",
+ self->tag, (unsigned char)self->value.c);
+ }
/* Hm, are these 'z' and 'Z' codes useful at all?
Shouldn't they be replaced by the functionality of c_string
@@ -505,16 +508,19 @@
case 'z':
case 'Z':
case 'P':
- sprintf(buffer, "<cparam '%c' (%p)>",
+ return PyUnicode_FromFormat("<cparam '%c' (%p)>",
self->tag, self->value.p);
- break;
default:
- sprintf(buffer, "<cparam '%c' at %p>",
- self->tag, self);
- break;
+ if (is_literal_char((unsigned char)self->tag)) {
+ return PyUnicode_FromFormat("<cparam '%c' at %p>",
+ (unsigned char)self->tag, (void *)self);
+ }
+ else {
+ return PyUnicode_FromFormat("<cparam 0x%02x at %p>",
+ (unsigned char)self->tag, (void *)self);
+ }
}
- return PyUnicode_FromString(buffer);
}
static PyMemberDef PyCArgType_members[] = {
