Skip to content

Commit

Permalink
pythongh-97897: Prevent os.mkfifo and os.mknod segfaults with macOS 1…
Browse files Browse the repository at this point in the history
…3 SDK (pythonGH-97944)

The macOS 13 SDK includes support for the `mkfifoat` and `mknodat` system calls.
 Using the `dir_fd` option with either `os.mkfifo` or `os.mknod` could result in a
 segfault if cpython is built with the macOS 13 SDK but run on an earlier
 version of macOS. Prevent this by adding runtime support for detection of
 these system calls ("weaklinking") as is done for other newer syscalls on
 macOS.
(cherry picked from commit 6d0a019)

Co-authored-by: Ned Deily <nad@python.org>
  • Loading branch information
ned-deily authored and miss-islington committed Oct 6, 2022
1 parent 358b7a4 commit 395d22d
Show file tree
Hide file tree
Showing 3 changed files with 80 additions and 8 deletions.
22 changes: 22 additions & 0 deletions Lib/test/test_posix.py
Original file line number Diff line number Diff line change
Expand Up @@ -2040,6 +2040,28 @@ def test_mkdir(self):
with self.assertRaisesRegex(NotImplementedError, "dir_fd unavailable"):
os.mkdir("dir", dir_fd=0)

def test_mkfifo(self):
self._verify_available("HAVE_MKFIFOAT")
if self.mac_ver >= (13, 0):
self.assertIn("HAVE_MKFIFOAT", posix._have_functions)

else:
self.assertNotIn("HAVE_MKFIFOAT", posix._have_functions)

with self.assertRaisesRegex(NotImplementedError, "dir_fd unavailable"):
os.mkfifo("path", dir_fd=0)

def test_mknod(self):
self._verify_available("HAVE_MKNODAT")
if self.mac_ver >= (13, 0):
self.assertIn("HAVE_MKNODAT", posix._have_functions)

else:
self.assertNotIn("HAVE_MKNODAT", posix._have_functions)

with self.assertRaisesRegex(NotImplementedError, "dir_fd unavailable"):
os.mknod("path", dir_fd=0)

def test_rename_replace(self):
self._verify_available("HAVE_RENAMEAT")
if self.mac_ver >= (10, 10):
Expand Down
Original file line number Diff line number Diff line change
@@ -0,0 +1,6 @@
The macOS 13 SDK includes support for the ``mkfifoat`` and ``mknodat`` system calls.
Using the ``dir_fd`` option with either :func:`os.mkfifo` or :func:`os.mknod` could result in a
segfault if cpython is built with the macOS 13 SDK but run on an earlier
version of macOS. Prevent this by adding runtime support for detection of
these system calls ("weaklinking") as is done for other newer syscalls on
macOS.
60 changes: 52 additions & 8 deletions Modules/posixmodule.c
Original file line number Diff line number Diff line change
Expand Up @@ -79,6 +79,8 @@
# define HAVE_FUTIMENS_RUNTIME __builtin_available(macOS 10.13, iOS 11.0, tvOS 11.0, watchOS 4.0, *)
# define HAVE_UTIMENSAT_RUNTIME __builtin_available(macOS 10.13, iOS 11.0, tvOS 11.0, watchOS 4.0, *)
# define HAVE_PWRITEV_RUNTIME __builtin_available(macOS 11.0, iOS 14.0, tvOS 14.0, watchOS 7.0, *)
# define HAVE_MKFIFOAT_RUNTIME __builtin_available(macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0, *)
# define HAVE_MKNODAT_RUNTIME __builtin_available(macOS 13.0, iOS 16.0, tvOS 16.0, watchOS 9.0, *)

# define HAVE_POSIX_SPAWN_SETSID_RUNTIME __builtin_available(macOS 10.15, *)

Expand Down Expand Up @@ -163,6 +165,8 @@
# define HAVE_FUTIMENS_RUNTIME 1
# define HAVE_UTIMENSAT_RUNTIME 1
# define HAVE_PWRITEV_RUNTIME 1
# define HAVE_MKFIFOAT_RUNTIME 1
# define HAVE_MKNODAT_RUNTIME 1
#endif


Expand Down Expand Up @@ -10482,18 +10486,35 @@ os_mkfifo_impl(PyObject *module, path_t *path, int mode, int dir_fd)
{
int result;
int async_err = 0;
#ifdef HAVE_MKFIFOAT
int mkfifoat_unavailable = 0;
#endif

do {
Py_BEGIN_ALLOW_THREADS
#ifdef HAVE_MKFIFOAT
if (dir_fd != DEFAULT_DIR_FD)
result = mkfifoat(dir_fd, path->narrow, mode);
else
if (dir_fd != DEFAULT_DIR_FD) {
if (HAVE_MKFIFOAT_RUNTIME) {
result = mkfifoat(dir_fd, path->narrow, mode);

} else {
mkfifoat_unavailable = 1;
result = 0;
}
} else
#endif
result = mkfifo(path->narrow, mode);
Py_END_ALLOW_THREADS
} while (result != 0 && errno == EINTR &&
!(async_err = PyErr_CheckSignals()));

#ifdef HAVE_MKFIFOAT
if (mkfifoat_unavailable) {
argument_unavailable_error(NULL, "dir_fd");
return NULL;
}
#endif

if (result != 0)
return (!async_err) ? posix_error() : NULL;

Expand Down Expand Up @@ -10534,18 +10555,33 @@ os_mknod_impl(PyObject *module, path_t *path, int mode, dev_t device,
{
int result;
int async_err = 0;
#ifdef HAVE_MKNODAT
int mknodat_unavailable = 0;
#endif

do {
Py_BEGIN_ALLOW_THREADS
#ifdef HAVE_MKNODAT
if (dir_fd != DEFAULT_DIR_FD)
result = mknodat(dir_fd, path->narrow, mode, device);
else
if (dir_fd != DEFAULT_DIR_FD) {
if (HAVE_MKNODAT_RUNTIME) {
result = mknodat(dir_fd, path->narrow, mode, device);

} else {
mknodat_unavailable = 1;
result = 0;
}
} else
#endif
result = mknod(path->narrow, mode, device);
Py_END_ALLOW_THREADS
} while (result != 0 && errno == EINTR &&
!(async_err = PyErr_CheckSignals()));
#ifdef HAVE_MKNODAT
if (mknodat_unavailable) {
argument_unavailable_error(NULL, "dir_fd");
return NULL;
}
#endif
if (result != 0)
return (!async_err) ? posix_error() : NULL;

Expand Down Expand Up @@ -15265,6 +15301,14 @@ PROBE(probe_fdopendir, HAVE_FDOPENDIR_RUNTIME)
PROBE(probe_mkdirat, HAVE_MKDIRAT_RUNTIME)
#endif

#ifdef HAVE_MKFIFOAT
PROBE(probe_mkfifoat, HAVE_MKFIFOAT_RUNTIME)
#endif

#ifdef HAVE_MKNODAT
PROBE(probe_mknodat, HAVE_MKNODAT_RUNTIME)
#endif

#ifdef HAVE_RENAMEAT
PROBE(probe_renameat, HAVE_RENAMEAT_RUNTIME)
#endif
Expand Down Expand Up @@ -15394,11 +15438,11 @@ static const struct have_function {
#endif

#ifdef HAVE_MKFIFOAT
{ "HAVE_MKFIFOAT", NULL },
{ "HAVE_MKFIFOAT", probe_mkfifoat },
#endif

#ifdef HAVE_MKNODAT
{ "HAVE_MKNODAT", NULL },
{ "HAVE_MKNODAT", probe_mknodat },
#endif

#ifdef HAVE_OPENAT
Expand Down

0 comments on commit 395d22d

Please sign in to comment.