Index: Misc/NEWS
===================================================================
--- Misc/NEWS	(revision 70604)
+++ Misc/NEWS	(working copy)
@@ -676,6 +676,8 @@
 
 - Issue #4396: The parser module now correctly validates the with statement.
 
+- Issue #5378: Stricter bounds check on mmap.move() to prevent segfaults from bad ranges.
+
 Tests
 -----
 
Index: Misc/ACKS
===================================================================
--- Misc/ACKS	(revision 70604)
+++ Misc/ACKS	(working copy)
@@ -775,6 +775,7 @@
 Thomas Wouters
 Heiko Wundram
 Doug Wyatt
+Hirokazu Yamamoto
 Ka-Ping Yee
 Bob Yodlowski
 Danny Yoo
@@ -787,6 +788,6 @@
 Mike Zarnstorff
 Siebren van der Zee
 Uwe Zessin
-Tarek ZiadŽ
+Tarek ZiadÂŽ
 Peter Åstrand
 Jesse Noller
Index: Lib/test/test_mmap.py
===================================================================
--- Lib/test/test_mmap.py	(revision 70604)
+++ Lib/test/test_mmap.py	(working copy)
@@ -335,6 +335,15 @@
         mf = mmap.mmap(f.fileno(), 10)
         mf.move(5, 0, 5)
         self.assertEqual(mf[:], "ABCDEABCDE", "Map move should have duplicated front 5")
+
+        # check bounds checking
+        self.assertRaises(ValueError, mf.move, -1, 0, 1)
+        self.assertRaises(ValueError, mf.move, 0, -1, 1)
+        self.assertRaises(ValueError, mf.move, 0, 0, -1)
+        self.assertRaises(ValueError, mf.move, mf.size(), 0, 1)
+        self.assertRaises(ValueError, mf.move, 0, mf.size(), 1)
+        self.assertEqual(None,  mf.move(0, 0, 0))
+
         mf.close()
         f.close()
 
Index: Modules/mmapmodule.c
===================================================================
--- Modules/mmapmodule.c	(revision 70604)
+++ Modules/mmapmodule.c	(working copy)
@@ -612,13 +612,14 @@
 		return NULL;
 	} else {
 		/* bounds check the values */
-		if (/* end of source after end of data?? */
-			((src+count) > self->size)
-			/* dest will fit? */
-			|| (dest+count > self->size)) {
+		if (src >= self->size || (src+count) > self->size) {
 			PyErr_SetString(PyExc_ValueError,
-					"source or destination out of range");
+				"source out of range");
 			return NULL;
+		} else if (dest >= self->size || (dest+count) > self->size) {
+			PyErr_SetString(PyExc_ValueError,
+				"destination out of range");
+			return NULL;
 		} else {
 			memmove(self->data+dest, self->data+src, count);
 			Py_INCREF(Py_None);