From 5405b295703055c9ea030e67279b5f6c37f6a51a Mon Sep 17 00:00:00 2001 From: Peter Korsgaard Date: Fri, 5 Feb 2021 14:07:56 +0100 Subject: [PATCH] package/python3: add upstream security fix for CVE-2021-3177 Fixes the following security issue: - CVE-2021-3177: Python 3.x through 3.9.1 has a buffer overflow in PyCArg_repr in _ctypes/callproc.c, which may lead to remote code execution in certain Python applications that accept floating-point numbers as untrusted input, as demonstrated by a 1e300 argument to c_double.from_param. This occurs because sprintf is used unsafely. For details, see the advisory: https://python-security.readthedocs.io/vuln/ctypes-buffer-overflow-pycarg_repr.html Signed-off-by: Peter Korsgaard --- ...-Replace-snprintf-with-Python-unicod.patch | 190 ++++++++++++++++++ package/python3/python3.mk | 3 + 2 files changed, 193 insertions(+) create mode 100644 package/python3/0035-closes-bpo-42938-Replace-snprintf-with-Python-unicod.patch diff --git a/package/python3/0035-closes-bpo-42938-Replace-snprintf-with-Python-unicod.patch b/package/python3/0035-closes-bpo-42938-Replace-snprintf-with-Python-unicod.patch new file mode 100644 index 0000000000..5f20265a23 --- /dev/null +++ b/package/python3/0035-closes-bpo-42938-Replace-snprintf-with-Python-unicod.patch @@ -0,0 +1,190 @@ +From c347cbe694743cee120457aa6626712f7799a932 Mon Sep 17 00:00:00 2001 +From: "Miss Islington (bot)" + <31488909+miss-islington@users.noreply.github.com> +Date: Mon, 18 Jan 2021 13:29:31 -0800 +Subject: [PATCH] closes bpo-42938: Replace snprintf with Python unicode + formatting in ctypes param reprs. (GH-24247) + +(cherry picked from commit 916610ef90a0d0761f08747f7b0905541f0977c7) + +Co-authored-by: Benjamin Peterson + +Co-authored-by: Benjamin Peterson +Signed-off-by: Peter Korsgaard +--- + Lib/ctypes/test/test_parameters.py | 43 ++++++++++++++++ + .../2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst | 2 + + Modules/_ctypes/callproc.c | 51 +++++++------------ + 3 files changed, 64 insertions(+), 32 deletions(-) + create mode 100644 Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst + +diff --git a/Lib/ctypes/test/test_parameters.py b/Lib/ctypes/test/test_parameters.py +index e4c25fd880..531894fdec 100644 +--- a/Lib/ctypes/test/test_parameters.py ++++ b/Lib/ctypes/test/test_parameters.py +@@ -201,6 +201,49 @@ class SimpleTypesTestCase(unittest.TestCase): + with self.assertRaises(ZeroDivisionError): + WorseStruct().__setstate__({}, b'foo') + ++ 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"^$") ++ self.assertEqual(repr(c_char.from_param(97)), "") ++ self.assertRegex(repr(c_wchar.from_param('a')), r"^$") ++ self.assertEqual(repr(c_byte.from_param(98)), "") ++ self.assertEqual(repr(c_ubyte.from_param(98)), "") ++ self.assertEqual(repr(c_short.from_param(511)), "") ++ self.assertEqual(repr(c_ushort.from_param(511)), "") ++ self.assertRegex(repr(c_int.from_param(20000)), r"^$") ++ self.assertRegex(repr(c_uint.from_param(20000)), r"^$") ++ self.assertRegex(repr(c_long.from_param(20000)), r"^$") ++ self.assertRegex(repr(c_ulong.from_param(20000)), r"^$") ++ self.assertRegex(repr(c_longlong.from_param(20000)), r"^$") ++ self.assertRegex(repr(c_ulonglong.from_param(20000)), r"^$") ++ self.assertEqual(repr(c_float.from_param(1.5)), "") ++ self.assertEqual(repr(c_double.from_param(1.5)), "") ++ self.assertEqual(repr(c_double.from_param(1e300)), "") ++ self.assertRegex(repr(c_longdouble.from_param(1.5)), r"^$") ++ self.assertRegex(repr(c_char_p.from_param(b'hihi')), "^$") ++ self.assertRegex(repr(c_wchar_p.from_param('hihi')), "^$") ++ self.assertRegex(repr(c_void_p.from_param(0x12)), r"^$") ++ + ################################################################ + + if __name__ == '__main__': +diff --git a/Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst b/Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst +new file mode 100644 +index 0000000000..7df65a156f +--- /dev/null ++++ b/Misc/NEWS.d/next/Security/2021-01-18-09-27-31.bpo-42938.4Zn4Mp.rst +@@ -0,0 +1,2 @@ ++Avoid static buffers when computing the repr of :class:`ctypes.c_double` and ++:class:`ctypes.c_longdouble` values. +diff --git a/Modules/_ctypes/callproc.c b/Modules/_ctypes/callproc.c +index b0a36a3024..f2506de544 100644 +--- a/Modules/_ctypes/callproc.c ++++ b/Modules/_ctypes/callproc.c +@@ -489,58 +489,47 @@ is_literal_char(unsigned char c) + static PyObject * + PyCArg_repr(PyCArgObject *self) + { +- char buffer[256]; + switch(self->tag) { + case 'b': + case 'B': +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.b); +- break; + case 'h': + case 'H': +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.h); +- break; + case 'i': + case 'I': +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.i); +- break; + case 'l': + case 'L': +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.l); +- break; + + case 'q': + case 'Q': +- sprintf(buffer, +-#ifdef MS_WIN32 +- "", +-#else +- "", +-#endif ++ return PyUnicode_FromFormat("", + self->tag, self->value.q); +- break; + case 'd': +- sprintf(buffer, "", +- self->tag, self->value.d); +- break; +- case 'f': +- sprintf(buffer, "", +- self->tag, self->value.f); +- break; +- ++ case 'f': { ++ PyObject *f = PyFloat_FromDouble((self->tag == 'f') ? self->value.f : self->value.d); ++ if (f == NULL) { ++ return NULL; ++ } ++ PyObject *result = PyUnicode_FromFormat("", self->tag, f); ++ Py_DECREF(f); ++ return result; ++ } + case 'c': + if (is_literal_char((unsigned char)self->value.c)) { +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.c); + } + else { +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, (unsigned char)self->value.c); + } +- break; + + /* Hm, are these 'z' and 'Z' codes useful at all? + Shouldn't they be replaced by the functionality of c_string +@@ -549,22 +538,20 @@ PyCArg_repr(PyCArgObject *self) + case 'z': + case 'Z': + case 'P': +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + self->tag, self->value.p); + break; + + default: + if (is_literal_char((unsigned char)self->tag)) { +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + (unsigned char)self->tag, (void *)self); + } + else { +- sprintf(buffer, "", ++ return PyUnicode_FromFormat("", + (unsigned char)self->tag, (void *)self); + } +- break; + } +- return PyUnicode_FromString(buffer); + } + + static PyMemberDef PyCArgType_members[] = { +-- +2.20.1 + diff --git a/package/python3/python3.mk b/package/python3/python3.mk index 8dbd0bab66..e85e704626 100644 --- a/package/python3/python3.mk +++ b/package/python3/python3.mk @@ -11,6 +11,9 @@ PYTHON3_SITE = https://python.org/ftp/python/$(PYTHON3_VERSION) PYTHON3_LICENSE = Python-2.0, others PYTHON3_LICENSE_FILES = LICENSE +# 0035-closes-bpo-42938-Replace-snprintf-with-Python-unicod.patch +PYTHON3_IGNORE_CVES += CVE-2021-3177 + # This host Python is installed in $(HOST_DIR), as it is needed when # cross-compiling third-party Python modules. -- 2.30.2