diff options
| -rw-r--r-- | Lib/test/test_mmap.py | 13 | ||||
| -rw-r--r-- | Misc/NEWS | 4 | ||||
| -rw-r--r-- | Modules/mmapmodule.c | 2 |
3 files changed, 18 insertions, 1 deletions
diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py index fba688e..5b99d00 100644 --- a/Lib/test/test_mmap.py +++ b/Lib/test/test_mmap.py @@ -324,6 +324,19 @@ class MmapTests(unittest.TestCase): mf.close() f.close() + def test_length_0_offset(self): + # Issue #10916: test mapping of remainder of file by passing 0 for + # map length with an offset doesn't cause a segfault. + if not hasattr(os, "stat"): + self.skipTest("needs os.stat") + with open(TESTFN, "wb+") as f: + f.write(49152 * b'm') # Arbitrary character + + with open(TESTFN, "rb") as f: + mf = mmap.mmap(f.fileno(), 0, offset=40960, access=mmap.ACCESS_READ) + self.assertRaises(IndexError, mf.__getitem__, 45000) + mf.close() + def test_move(self): # make move works everywhere (64-bit format problem earlier) f = open(TESTFN, 'wb+') @@ -34,6 +34,10 @@ Core and Builtins Library ------- +- Issue #10916: mmap should not segfault when a file is mapped using 0 as + length and a non-zero offset, and an attempt to read past the end of file + is made (IndexError is raised instead). Patch by Ross Lagerwall. + - Issue #10899: No function type annotations in the standard library. Removed function type annotations from _pyio.py. diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c index 79a8a68..199d960 100644 --- a/Modules/mmapmodule.c +++ b/Modules/mmapmodule.c @@ -1085,7 +1085,7 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict) # endif if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) { if (map_size == 0) { - map_size = st.st_size; + map_size = st.st_size - offset; } else if ((size_t)offset + (size_t)map_size > st.st_size) { PyErr_SetString(PyExc_ValueError, "mmap length is greater than file size"); |