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.
Requested by Georg.
diff --git a/Lib/test/test_mmap.py b/Lib/test/test_mmap.py
index abfde01..c7b8d60 100644
--- a/Lib/test/test_mmap.py
+++ b/Lib/test/test_mmap.py
@@ -320,6 +320,19 @@
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+')
diff --git a/Misc/NEWS b/Misc/NEWS
index 68aae79..6524dcf 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -43,6 +43,10 @@
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 #10907: Warn OS X 10.6 IDLE users to use ActiveState Tcl/Tk 8.5,
rather than the currently problematic Apple-supplied one, when running
with the 64-/32-bit installer variant.
diff --git a/Modules/mmapmodule.c b/Modules/mmapmodule.c
index 8a22752..ef026b2 100644
--- a/Modules/mmapmodule.c
+++ b/Modules/mmapmodule.c
@@ -1116,7 +1116,7 @@
# 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");