gh-89928: Fix integer conversion of device numbers (GH-31794)

Fix os.major(), os.minor() and os.makedev().
Support device numbers larger than 2**63-1.
Support non-existent device number (NODEV).
(cherry picked from commit 7111d96)

Co-authored-by: Serhiy Storchaka <[email protected]>

Lib/test/test_posix.py

@@ -704,21 +704,32 @@ def test_makedev(self):
         self.assertEqual(posix.major(dev), major)
         self.assertRaises(TypeError, posix.major, float(dev))
         self.assertRaises(TypeError, posix.major)
-        self.assertRaises((ValueError, OverflowError), posix.major, -1)
+        for x in -2, 2**64, -2**63-1:
+            self.assertRaises((ValueError, OverflowError), posix.major, x)
 
         minor = posix.minor(dev)
         self.assertIsInstance(minor, int)
         self.assertGreaterEqual(minor, 0)
         self.assertEqual(posix.minor(dev), minor)
         self.assertRaises(TypeError, posix.minor, float(dev))
         self.assertRaises(TypeError, posix.minor)
-        self.assertRaises((ValueError, OverflowError), posix.minor, -1)
+        for x in -2, 2**64, -2**63-1:
+            self.assertRaises((ValueError, OverflowError), posix.minor, x)
 
         self.assertEqual(posix.makedev(major, minor), dev)
         self.assertRaises(TypeError, posix.makedev, float(major), minor)
         self.assertRaises(TypeError, posix.makedev, major, float(minor))
         self.assertRaises(TypeError, posix.makedev, major)
         self.assertRaises(TypeError, posix.makedev)
+        for x in -2, 2**32, 2**64, -2**63-1:
+            self.assertRaises((ValueError, OverflowError), posix.makedev, x, minor)
+            self.assertRaises((ValueError, OverflowError), posix.makedev, major, x)
+
+        if sys.platform == 'linux':
+            NODEV = -1
+            self.assertEqual(posix.major(NODEV), NODEV)
+            self.assertEqual(posix.minor(NODEV), NODEV)
+            self.assertEqual(posix.makedev(NODEV, NODEV), NODEV)
 
     def _test_all_chown_common(self, chown_func, first_param, stat_func):
         """Common code for chown, fchown and lchown tests."""

Misc/NEWS.d/next/Library/2022-03-10-16-47-57.bpo-45767.ywmyo1.rst

@@ -0,0 +1,3 @@
+Fix integer conversion in :func:`os.major`, :func:`os.minor`, and
+:func:`os.makedev`. Support device numbers larger than ``2**63-1``. Support
+non-existent device number (``NODEV``).

Modules/posixmodule.c

@@ -18,6 +18,7 @@
 #include "pycore_fileutils.h"     // _Py_closerange()
 #include "pycore_import.h"        // _PyImport_ReInitLock()
 #include "pycore_initconfig.h"    // _PyStatus_EXCEPTION()
+#include "pycore_long.h"          // _PyLong_IsNegative()
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_object.h"        // _PyObject_LookupSpecial()
 #include "pycore_pylifecycle.h"   // _PyOS_URandom()
@@ -967,16 +968,46 @@ _Py_Gid_Converter(PyObject *obj, gid_t *p)
 #endif /* MS_WINDOWS */
 
 
-#define _PyLong_FromDev PyLong_FromLongLong
+static PyObject *
+_PyLong_FromDev(dev_t dev)
+{
+#ifdef NODEV
+    if (dev == NODEV) {
+        return PyLong_FromLongLong((long long)dev);
+    }
+#endif
+    return PyLong_FromUnsignedLongLong((unsigned long long)dev);
+}
 
 
 #if (defined(HAVE_MKNOD) && defined(HAVE_MAKEDEV)) || defined(HAVE_DEVICE_MACROS)
 static int
 _Py_Dev_Converter(PyObject *obj, void *p)
 {
-    *((dev_t *)p) = PyLong_AsUnsignedLongLong(obj);
-    if (PyErr_Occurred())
+#ifdef NODEV
+    if (PyLong_Check(obj) && _PyLong_IsNegative((PyLongObject *)obj)) {
+        int overflow;
+        long long result = PyLong_AsLongLongAndOverflow(obj, &overflow);
+        if (result == -1 && PyErr_Occurred()) {
+            return 0;
+        }
+        if (!overflow && result == (long long)NODEV) {
+            *((dev_t *)p) = NODEV;
+            return 1;
+        }
+    }
+#endif
+
+    unsigned long long result = PyLong_AsUnsignedLongLong(obj);
+    if (result == (unsigned long long)-1 && PyErr_Occurred()) {
+        return 0;
+    }
+    if ((unsigned long long)(dev_t)result != result) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "Python int too large to convert to C dev_t");
         return 0;
+    }
+    *((dev_t *)p) = (dev_t)result;
     return 1;
 }
 #endif /* (HAVE_MKNOD && HAVE_MAKEDEV) || HAVE_DEVICE_MACROS */
@@ -12517,55 +12548,82 @@ os_mknod_impl(PyObject *module, path_t *path, int mode, dev_t device,
 #endif /* defined(HAVE_MKNOD) && defined(HAVE_MAKEDEV) */
 
 
+static PyObject *
+major_minor_conv(unsigned int value)
+{
+#ifdef NODEV
+    if (value == (unsigned int)NODEV) {
+        return PyLong_FromLong((int)NODEV);
+    }
+#endif
+    return PyLong_FromUnsignedLong(value);
+}
+
+static int
+major_minor_check(dev_t value)
+{
+#ifdef NODEV
+    if (value == NODEV) {
+        return 1;
+    }
+#endif
+    return (dev_t)(unsigned int)value == value;
+}
+
 #ifdef HAVE_DEVICE_MACROS
 /*[clinic input]
-os.major -> unsigned_int
+os.major
 
     device: dev_t
     /
 
 Extracts a device major number from a raw device number.
 [clinic start generated code]*/
 
-static unsigned int
+static PyObject *
 os_major_impl(PyObject *module, dev_t device)
-/*[clinic end generated code: output=5b3b2589bafb498e input=1e16a4d30c4d4462]*/
+/*[clinic end generated code: output=4071ffee17647891 input=b1a0a14ec9448229]*/
 {
-    return major(device);
+    return major_minor_conv(major(device));
 }
 
 
 /*[clinic input]
-os.minor -> unsigned_int
+os.minor
 
     device: dev_t
     /
 
 Extracts a device minor number from a raw device number.
 [clinic start generated code]*/
 
-static unsigned int
+static PyObject *
 os_minor_impl(PyObject *module, dev_t device)
-/*[clinic end generated code: output=5e1a25e630b0157d input=0842c6d23f24c65e]*/
+/*[clinic end generated code: output=306cb78e3bc5004f input=2f686e463682a9da]*/
 {
-    return minor(device);
+    return major_minor_conv(minor(device));
 }
 
 
 /*[clinic input]
 os.makedev -> dev_t
 
-    major: int
-    minor: int
+    major: dev_t
+    minor: dev_t
     /
 
 Composes a raw device number from the major and minor device numbers.
 [clinic start generated code]*/
 
 static dev_t
-os_makedev_impl(PyObject *module, int major, int minor)
-/*[clinic end generated code: output=881aaa4aba6f6a52 input=4b9fd8fc73cbe48f]*/
+os_makedev_impl(PyObject *module, dev_t major, dev_t minor)
+/*[clinic end generated code: output=cad6125c51f5af80 input=2146126ec02e55c1]*/
 {
+    if (!major_minor_check(major) || !major_minor_check(minor)) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "Python int too large to convert to C unsigned int");
+        return (dev_t)-1;
+    }
     return makedev(major, minor);
 }
 #endif /* HAVE_DEVICE_MACROS */