[3.6] bpo-31675: Fix memory leaks in Tkinter's methods splitlist() and split() (GH-3866) (#3874)

when pass a string larger than 2 GiB.

Decrease memory requirements for Tcl's bigmem tests.
(cherry picked from commit 27c623c8)

Lib/test/test_tcl.py

@@ -662,32 +662,44 @@ class BigmemTclTest(unittest.TestCase):
     @support.bigmemtest(size=INT_MAX + 1, memuse=5, dry_run=False)
     def test_huge_string_call(self, size):
         value = ' ' * size
-        self.assertRaises(OverflowError, self.interp.call, 'set', '_', value)
+        self.assertRaises(OverflowError, self.interp.call, 'string', 'index', value, 0)
 
     @support.cpython_only
     @unittest.skipUnless(INT_MAX < PY_SSIZE_T_MAX, "needs UINT_MAX < SIZE_MAX")
-    @support.bigmemtest(size=INT_MAX + 1, memuse=9, dry_run=False)
+    @support.bigmemtest(size=INT_MAX + 1, memuse=2, dry_run=False)
     def test_huge_string_builtins(self, size):
+        tk = self.interp.tk
         value = '1' + ' ' * size
-        self.assertRaises(OverflowError, self.interp.tk.getint, value)
-        self.assertRaises(OverflowError, self.interp.tk.getdouble, value)
-        self.assertRaises(OverflowError, self.interp.tk.getboolean, value)
-        self.assertRaises(OverflowError, self.interp.eval, value)
-        self.assertRaises(OverflowError, self.interp.evalfile, value)
-        self.assertRaises(OverflowError, self.interp.record, value)
-        self.assertRaises(OverflowError, self.interp.adderrorinfo, value)
-        self.assertRaises(OverflowError, self.interp.setvar, value, 'x', 'a')
-        self.assertRaises(OverflowError, self.interp.setvar, 'x', value, 'a')
-        self.assertRaises(OverflowError, self.interp.unsetvar, value)
-        self.assertRaises(OverflowError, self.interp.unsetvar, 'x', value)
-        self.assertRaises(OverflowError, self.interp.adderrorinfo, value)
-        self.assertRaises(OverflowError, self.interp.exprstring, value)
-        self.assertRaises(OverflowError, self.interp.exprlong, value)
-        self.assertRaises(OverflowError, self.interp.exprboolean, value)
-        self.assertRaises(OverflowError, self.interp.splitlist, value)
-        self.assertRaises(OverflowError, self.interp.split, value)
-        self.assertRaises(OverflowError, self.interp.createcommand, value, max)
-        self.assertRaises(OverflowError, self.interp.deletecommand, value)
+        self.assertRaises(OverflowError, tk.getint, value)
+        self.assertRaises(OverflowError, tk.getdouble, value)
+        self.assertRaises(OverflowError, tk.getboolean, value)
+        self.assertRaises(OverflowError, tk.eval, value)
+        self.assertRaises(OverflowError, tk.evalfile, value)
+        self.assertRaises(OverflowError, tk.record, value)
+        self.assertRaises(OverflowError, tk.adderrorinfo, value)
+        self.assertRaises(OverflowError, tk.setvar, value, 'x', 'a')
+        self.assertRaises(OverflowError, tk.setvar, 'x', value, 'a')
+        self.assertRaises(OverflowError, tk.unsetvar, value)
+        self.assertRaises(OverflowError, tk.unsetvar, 'x', value)
+        self.assertRaises(OverflowError, tk.adderrorinfo, value)
+        self.assertRaises(OverflowError, tk.exprstring, value)
+        self.assertRaises(OverflowError, tk.exprlong, value)
+        self.assertRaises(OverflowError, tk.exprboolean, value)
+        self.assertRaises(OverflowError, tk.splitlist, value)
+        self.assertRaises(OverflowError, tk.split, value)
+        self.assertRaises(OverflowError, tk.createcommand, value, max)
+        self.assertRaises(OverflowError, tk.deletecommand, value)
+
+    @support.cpython_only
+    @unittest.skipUnless(INT_MAX < PY_SSIZE_T_MAX, "needs UINT_MAX < SIZE_MAX")
+    @support.bigmemtest(size=INT_MAX + 1, memuse=6, dry_run=False)
+    def test_huge_string_builtins2(self, size):
+        # These commands require larger memory for possible error messages
+        tk = self.interp.tk
+        value = '1' + ' ' * size
+        self.assertRaises(OverflowError, tk.evalfile, value)
+        self.assertRaises(OverflowError, tk.unsetvar, value)
+        self.assertRaises(OverflowError, tk.unsetvar, 'x', value)
 
 
 def setUpModule():

Misc/NEWS.d/next/Library/2017-10-03-15-06-24.bpo-31675.Nh7jJ3.rst

+Fixed memory leaks in Tkinter's methods splitlist() and split() when pass a
+string larger than 2 GiB.

Modules/_tkinter.c

@@ -2291,7 +2291,11 @@ _tkinter_tkapp_splitlist(TkappObject *self, PyObject *arg)
     if (!PyArg_Parse(arg, "et:splitlist", "utf-8", &list))
         return NULL;
 
-    CHECK_STRING_LENGTH(list);
+    if (strlen(list) >= INT_MAX) {
+        PyErr_SetString(PyExc_OverflowError, "string is too long");
+        PyMem_Free(list);
+        return NULL;
+    }
     if (Tcl_SplitList(Tkapp_Interp(self), list,
                       &argc, &argv) == TCL_ERROR)  {
         PyMem_Free(list);
@@ -2362,7 +2366,11 @@ _tkinter_tkapp_split(TkappObject *self, PyObject *arg)
 
     if (!PyArg_Parse(arg, "et:split", "utf-8", &list))
         return NULL;
-    CHECK_STRING_LENGTH(list);
+    if (strlen(list) >= INT_MAX) {
+        PyErr_SetString(PyExc_OverflowError, "string is too long");
+        PyMem_Free(list);
+        return NULL;
+    }
     v = Split(list);
     PyMem_Free(list);
     return v;