Issue #17919: Fixed integer overflow in the eventmask parameter.

Lib/test/test_poll.py

@@ -3,7 +3,7 @@
 import os
 import random
 import select
-import _testcapi
+from _testcapi import USHRT_MAX, INT_MAX, UINT_MAX
 try:
     import threading
 except ImportError:
@@ -159,10 +159,13 @@ class PollTests(unittest.TestCase):
         if x != 5:
             self.fail('Overflow must have occurred')
 
-        pollster = select.poll()
-        # Issue 15989
-        self.assertRaises(OverflowError, pollster.poll, _testcapi.INT_MAX + 1)
-        self.assertRaises(OverflowError, pollster.poll, _testcapi.UINT_MAX + 1)
+        # Issues #15989, #17919
+        self.assertRaises(OverflowError, pollster.register, 0, -1)
+        self.assertRaises(OverflowError, pollster.register, 0, USHRT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.modify, 1, -1)
+        self.assertRaises(OverflowError, pollster.modify, 1, USHRT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.poll, INT_MAX + 1)
+        self.assertRaises(OverflowError, pollster.poll, UINT_MAX + 1)
 
     @unittest.skipUnless(threading, 'Threading required for this test.')
     @reap_threads

Misc/NEWS

@@ -23,7 +23,8 @@ Core and Builtins
 Library
 -------
 
-- Issue #17919: select.poll.poll() again works with poll.POLLNVAL on AIX.
+- Issue #17919: select.poll.register() again works with poll.POLLNVAL on AIX.
+  Fixed integer overflow in the eventmask parameter.
 
 - Issue #17200: telnetlib's read_until and expect timeout was broken by the
   fix to Issue #14635 in Python 2.7.4 to be interpreted as milliseconds

Modules/selectmodule.c

@@ -347,7 +347,7 @@ update_ufd_array(pollObject *self)
         assert(i < self->ufd_len);
         /* Never overflow */
         self->ufds[i].fd = (int)PyInt_AsLong(key);
-        self->ufds[i].events = (short)PyInt_AsLong(value);
+        self->ufds[i].events = (short)(unsigned short)PyInt_AsLong(value);
         i++;
     }
     assert(i == self->ufd_len);
@@ -355,6 +355,24 @@ update_ufd_array(pollObject *self)
     return 1;
 }
 
+static int
+ushort_converter(PyObject *obj, void *ptr)
+{
+    unsigned long uval;
+
+    uval = PyLong_AsUnsignedLong(obj);
+    if (uval == (unsigned long)-1 && PyErr_Occurred())
+        return 0;
+    if (uval > USHRT_MAX) {
+        PyErr_SetString(PyExc_OverflowError,
+                        "Python int too large for C unsigned short");
+        return 0;
+    }
+
+    *(unsigned short *)ptr = Py_SAFE_DOWNCAST(uval, unsigned long, unsigned short);
+    return 1;
+}
+
 PyDoc_STRVAR(poll_register_doc,
 "register(fd [, eventmask] ) -> None\n\n\
 Register a file descriptor with the polling object.\n\
@@ -366,12 +384,12 @@ static PyObject *
 poll_register(pollObject *self, PyObject *args)
 {
     PyObject *o, *key, *value;
-    int fd, events = POLLIN | POLLPRI | POLLOUT;
+    int fd;
+    unsigned short events = POLLIN | POLLPRI | POLLOUT;
     int err;
 
-    if (!PyArg_ParseTuple(args, "O|i:register", &o, &events)) {
+    if (!PyArg_ParseTuple(args, "O|O&:register", &o, ushort_converter, &events))
         return NULL;
-    }
 
     fd = PyObject_AsFileDescriptor(o);
     if (fd == -1) return NULL;
@@ -409,12 +427,12 @@ static PyObject *
 poll_modify(pollObject *self, PyObject *args)
 {
     PyObject *o, *key, *value;
-    int fd, events;
+    int fd;
+    unsigned short events;
     int err;
 
-    if (!PyArg_ParseTuple(args, "Oi:modify", &o, &events)) {
+    if (!PyArg_ParseTuple(args, "OO&:modify", &o, ushort_converter, &events))
         return NULL;
-    }
 
     fd = PyObject_AsFileDescriptor(o);
     if (fd == -1) return NULL;