From 77796d058e780083279994dfbfca71caf95d1e7d Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
<31488909+miss-islington@users.noreply.github.com>
Date: Thu, 6 Oct 2022 12:14:32 -0700
Subject: [PATCH] [3.9] gh-97897: Prevent os.mkfifo and os.mknod segfaults with
macOS 13 SDK (GH-97944) (#97968)
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 6d0a0191a4e5477bd843e62c24d7f3bcad4fd5fc)
Co-authored-by: Ned Deily <nad@python.org>
---
Lib/test/test_posix.py | 22 +++++++
...2-10-05-15-26-58.gh-issue-97897.Rf-C6u.rst | 6 ++
Modules/posixmodule.c | 60 ++++++++++++++++---
3 files changed, 80 insertions(+), 8 deletions(-)
create mode 100644 Misc/NEWS.d/next/macOS/2022-10-05-15-26-58.gh-issue-97897.Rf-C6u.rst
diff --git a/Lib/test/test_posix.py b/Lib/test/test_posix.py
index 6ba14547bdd..3c0ddeb0037 100644
--- a/Lib/test/test_posix.py
+++ b/Lib/test/test_posix.py
@@ -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):
diff --git a/Misc/NEWS.d/next/macOS/2022-10-05-15-26-58.gh-issue-97897.Rf-C6u.rst b/Misc/NEWS.d/next/macOS/2022-10-05-15-26-58.gh-issue-97897.Rf-C6u.rst
new file mode 100644
index 00000000000..0d21e98b37c
--- /dev/null
+++ b/Misc/NEWS.d/next/macOS/2022-10-05-15-26-58.gh-issue-97897.Rf-C6u.rst
@@ -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.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index 1270af735e2..bf4e648421d 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -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, *)
@@ -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
@@ -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;
@@ -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;
@@ -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
@@ -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
--
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