From 941bfcc537a25077e2a73ddf8d8b3bfe288c81f4 Mon Sep 17 00:00:00 2001 From: Jesus Cea Date: Mon, 10 Sep 2012 00:27:55 +0200 Subject: [PATCH] Closes #15676: mmap: add empty file check prior to offset check --- Lib/test/test_mmap.py | 9 +++++++++ Misc/NEWS | 3 +++ Modules/mmapmodule.c | 5 +++++ 3 files changed, 17 insertions(+) diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py index 0e18aabd66..c060e61dda 100644 --- a/Lib/test/test_mmap.py +++ b/Lib/test/test_mmap.py @@ -459,6 +459,15 @@ class MmapTests(unittest.TestCase): f.flush () return mmap.mmap (f.fileno(), 0) + def test_empty_file (self): + f = open (TESTFN, 'w+b') + f.close() + f = open(TESTFN, "rb") + self.assertRaisesRegex(ValueError, + "cannot mmap an empty file", + mmap.mmap, f.fileno(), 0, access=mmap.ACCESS_READ) + f.close() + def test_offset (self): f = open (TESTFN, 'w+b') diff --git a/Misc/NEWS b/Misc/NEWS index 8672b0a468..725fb9e5c1 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -463,6 +463,9 @@ Library Extension Modules ----------------- +- Issue #15676: Now "mmap" check for empty files before doing the + offset check. Patch by Steven Willis. + - Issue #6493: An issue in ctypes on Windows that caused structure bitfields of type ctypes.c_uint32 and width 32 to incorrectly be set has been fixed. diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c index da9283bf1b..e23613eb12 100644 --- a/Modules/mmapmodule.c +++ b/Modules/mmapmodule.c @@ -1141,6 +1141,11 @@ new_mmap_object(PyTypeObject *type, PyObject *args, PyObject *kwdict) if (fd != -1 && fstat(fd, &st) == 0 && S_ISREG(st.st_mode)) { if (map_size == 0) { off_t calc_size; + if (st.st_size == 0) { + PyErr_SetString(PyExc_ValueError, + "cannot mmap an empty file"); + return NULL; + } if (offset >= st.st_size) { PyErr_SetString(PyExc_ValueError, "mmap offset is greater than file size"); -- 2.40.0