don't allow null character in strings being encoded

mongodb · Jun 18, 2009 · b839cd7 · b839cd7
1 parent 51bf841
commit b839cd7
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Showing 3 changed files with 19 additions and 3 deletions.
diff --git a/pymongo/_cbsonmodule.c b/pymongo/_cbsonmodule.c
@@ -26,6 +26,7 @@
 
 static PyObject* CBSONError;
 static PyObject* InvalidName;
+static PyObject* InvalidDocument;
 static PyObject* SON;
 static PyObject* Binary;
 static PyObject* Code;
@@ -177,12 +178,20 @@ static int write_shuffled_oid(bson_buffer* buffer, const char* oid) {
 
 /* returns 0 on failure */
 static int write_string(bson_buffer* buffer, PyObject* py_string) {
-    int string_length;
+    int i;
+    Py_ssize_t string_length;
     const char* string = PyString_AsString(py_string);
     if (!string) {
         return 1;
     }
-    string_length = strlen(string) + 1;
+    string_length = PyString_Size(py_string) + 1;
+
+    for (i = 0; i < string_length - 1; i++) {
+        if (string[i] == 0) {
+            PyErr_SetString(InvalidDocument, "BSON strings must not contain a NULL character");
+            return 0;
+        }
+    }
 
     if (!buffer_write_bytes(buffer, (const char*)&string_length, 4)) {
         return 0;
@@ -1189,6 +1198,7 @@ PyMODINIT_FUNC init_cbson(void) {
     }
     CBSONError = PyObject_GetAttrString(module, "InvalidDocument");
     InvalidName = PyObject_GetAttrString(module, "InvalidName");
+    InvalidDocument = PyObject_GetAttrString(module, "InvalidDocument");
     Py_DECREF(module);
 
     module = PyImport_ImportModule("pymongo.son");

diff --git a/pymongo/bson.py b/pymongo/bson.py
@@ -56,6 +56,8 @@ def _get_c_string(data):
 
 
 def _make_c_string(string):
+    if "\x00" in string:
+        raise InvalidDocument("BSON strings must not contain a NULL character")
     return string.encode("utf-8") + "\x00"
 
 

diff --git a/test/test_bson.py b/test/test_bson.py
@@ -30,7 +30,7 @@
 from pymongo.dbref import DBRef
 from pymongo.son import SON
 from pymongo.bson import BSON, is_valid, _to_dicts
-from pymongo.errors import UnsupportedTag
+from pymongo.errors import UnsupportedTag, InvalidDocument
 
 
 class TestBSON(unittest.TestCase):
@@ -131,6 +131,10 @@ def test_basic_from_dict(self):
                          "\x00\x05\x00\x00\x00coll\x00\x07$id\x00\x07\x06\x05"
                          "\x04\x03\x02\x01\x00\x0B\x0A\x09\x08\x00\x00")
 
+    def test_null_character_encoding(self):
+        self.assertRaises(InvalidDocument, BSON.from_dict, {"with zero": "hello\x00world"})
+        self.assertRaises(InvalidDocument, BSON.from_dict, {"with zero": u"hello\x00world"})
+
     def test_from_then_to_dict(self):
 
         def helper(dict):