[Python-checkins] cpython (3.1): in scan_once, prevent the reading of arbitrary memory when passed a negative
benjamin.peterson
python-checkins at python.org
Mon Apr 14 04:32:22 CEST 2014
http://hg.python.org/cpython/rev/a8facac493ef
changeset: 90235:a8facac493ef
branch: 3.1
parent: 89608:23add5382fb3
user: Benjamin Peterson <benjamin at python.org>
date: Sun Apr 13 22:10:38 2014 -0400
summary:
in scan_once, prevent the reading of arbitrary memory when passed a negative index
Bug reported by Guido Vranken.
files:
Lib/json/tests/test_decode.py | 4 ++++
Misc/ACKS | 1 +
Misc/NEWS | 3 +++
Modules/_json.c | 5 ++++-
4 files changed, 12 insertions(+), 1 deletions(-)
diff --git a/Lib/json/tests/test_decode.py b/Lib/json/tests/test_decode.py
--- a/Lib/json/tests/test_decode.py
+++ b/Lib/json/tests/test_decode.py
@@ -45,5 +45,9 @@
self.assertEqual(rval, {"key":"value", "k":"v"})
+ def test_negative_index(self):
+ d = self.json.JSONDecoder()
+ self.assertRaises(ValueError, d.raw_decode, 'a'*42, -50000)
+
class TestPyDecode(TestDecode, PyTest): pass
class TestCDecode(TestDecode, CTest): pass
diff --git a/Misc/ACKS b/Misc/ACKS
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -842,6 +842,7 @@
Kurt Vile
Norman Vine
Frank Visser
+Guido Vranken
Niki W. Waibel
Wojtek Walczak
Charles Waldman
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,9 @@
Library
-------
+- Fix arbitrary memory access in JSONDecoder.raw_decode with a negative second
+ parameter. Bug reported by Guido Vranken.
+
- Issue #20246: Fix buffer overflow in socket.recvfrom_into.
- Issue #19435: Fix directory traversal attack on CGIHttpRequestHandler.
diff --git a/Modules/_json.c b/Modules/_json.c
--- a/Modules/_json.c
+++ b/Modules/_json.c
@@ -902,7 +902,10 @@
PyObject *res;
Py_UNICODE *str = PyUnicode_AS_UNICODE(pystr);
Py_ssize_t length = PyUnicode_GET_SIZE(pystr);
- if (idx >= length) {
+ if (idx < 0)
+ /* Compatibility with Python version. */
+ idx += length;
+ if (idx < 0 || idx >= length) {
PyErr_SetNone(PyExc_StopIteration);
return NULL;
}
--
Repository URL: http://hg.python.org/cpython
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