Fixes issue #16140: The subprocess module no longer double closes its

child subprocess.PIPE parent file descriptors on child error prior to
exec().

This would lead to race conditions in multithreaded programs where
another thread opened a file reusing the fd which was then closed out
from beneath it by the errant second close.

1 files changed, 129 insertions, 36 deletions

diff --git a/Python/errors.c b/Python/errors.c
index 5a9a624279..626b16e46f 100644
--- a/Python/errors.c
+++ b/Python/errors.c
@@ -320,6 +320,39 @@ PyErr_Clear(void)
     PyErr_Restore(NULL, NULL, NULL);
 }
 
+void
+PyErr_GetExcInfo(PyObject **p_type, PyObject **p_value, PyObject **p_traceback)
+{
+    PyThreadState *tstate = PyThreadState_GET();
+
+    *p_type = tstate->exc_type;
+    *p_value = tstate->exc_value;
+    *p_traceback = tstate->exc_traceback;
+
+    Py_XINCREF(*p_type);
+    Py_XINCREF(*p_value);
+    Py_XINCREF(*p_traceback);
+}
+
+void
+PyErr_SetExcInfo(PyObject *p_type, PyObject *p_value, PyObject *p_traceback)
+{
+    PyObject *oldtype, *oldvalue, *oldtraceback;
+    PyThreadState *tstate = PyThreadState_GET();
+
+    oldtype = tstate->exc_type;
+    oldvalue = tstate->exc_value;
+    oldtraceback = tstate->exc_traceback;
+
+    tstate->exc_type = p_type;
+    tstate->exc_value = p_value;
+    tstate->exc_traceback = p_traceback;
+
+    Py_XDECREF(oldtype);
+    Py_XDECREF(oldvalue);
+    Py_XDECREF(oldtraceback);
+}
+
 /* Convenience functions to set a type error exception and return 0 */
 
 int
@@ -341,11 +374,9 @@ PyObject *
 PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
 {
     PyObject *message;
-    PyObject *v;
+    PyObject *v, *args;
     int i = errno;
-#ifndef MS_WINDOWS
-    char *s;
-#else
+#ifdef MS_WINDOWS
     WCHAR *s_buf = NULL;
 #endif /* Unix/Windows */
 
@@ -355,11 +386,14 @@ PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
 #endif
 
 #ifndef MS_WINDOWS
-    if (i == 0)
-        s = "Error"; /* Sometimes errno didn't get set */
-    else
-        s = strerror(i);
-    message = PyUnicode_DecodeUTF8(s, strlen(s), "ignore");
+    if (i != 0) {
+        char *s = strerror(i);
+        message = PyUnicode_DecodeLocale(s, "surrogateescape");
+    }
+    else {
+        /* Sometimes errno didn't get set */
+        message = PyUnicode_FromString("Error");
+    }
 #else
     if (i == 0)
         message = PyUnicode_FromString("Error"); /* Sometimes errno didn't get set */
@@ -395,7 +429,7 @@ PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
                 /* remove trailing cr/lf and dots */
                 while (len > 0 && (s_buf[len-1] <= L' ' || s_buf[len-1] == L'.'))
                     s_buf[--len] = L'\0';
-                message = PyUnicode_FromUnicode(s_buf, len);
+                message = PyUnicode_FromWideChar(s_buf, len);
             }
         }
     }
@@ -410,14 +444,18 @@ PyErr_SetFromErrnoWithFilenameObject(PyObject *exc, PyObject *filenameObject)
     }
 
     if (filenameObject != NULL)
-        v = Py_BuildValue("(iOO)", i, message, filenameObject);
+        args = Py_BuildValue("(iOO)", i, message, filenameObject);
     else
-        v = Py_BuildValue("(iO)", i, message);
+        args = Py_BuildValue("(iO)", i, message);
     Py_DECREF(message);
 
-    if (v != NULL) {
-        PyErr_SetObject(exc, v);
-        Py_DECREF(v);
+    if (args != NULL) {
+        v = PyObject_Call(exc, args, NULL);
+        Py_DECREF(args);
+        if (v != NULL) {
+            PyErr_SetObject((PyObject *) Py_TYPE(v), v);
+            Py_DECREF(v);
+        }
     }
 #ifdef MS_WINDOWS
     LocalFree(s_buf);
@@ -464,7 +502,7 @@ PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(
     int len;
     WCHAR *s_buf = NULL; /* Free via LocalFree */
     PyObject *message;
-    PyObject *v;
+    PyObject *args, *v;
     DWORD err = (DWORD)ierr;
     if (err==0) err = GetLastError();
     len = FormatMessageW(
@@ -487,7 +525,7 @@ PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(
         /* remove trailing cr/lf and dots */
         while (len > 0 && (s_buf[len-1] <= L' ' || s_buf[len-1] == L'.'))
             s_buf[--len] = L'\0';
-        message = PyUnicode_FromUnicode(s_buf, len);
+        message = PyUnicode_FromWideChar(s_buf, len);
     }
 
     if (message == NULL)
@@ -496,15 +534,20 @@ PyObject *PyErr_SetExcFromWindowsErrWithFilenameObject(
         return NULL;
     }
 
-    if (filenameObject != NULL)
-        v = Py_BuildValue("(iOO)", err, message, filenameObject);
-    else
-        v = Py_BuildValue("(iO)", err, message);
+    if (filenameObject == NULL)
+        filenameObject = Py_None;
+    /* This is the constructor signature for passing a Windows error code.
+       The POSIX translation will be figured out by the constructor. */
+    args = Py_BuildValue("(iOOi)", 0, message, filenameObject, err);
     Py_DECREF(message);
 
-    if (v != NULL) {
-        PyErr_SetObject(exc, v);
-        Py_DECREF(v);
+    if (args != NULL) {
+        v = PyObject_Call(exc, args, NULL);
+        Py_DECREF(args);
+        if (v != NULL) {
+            PyErr_SetObject((PyObject *) Py_TYPE(v), v);
+            Py_DECREF(v);
+        }
     }
     LocalFree(s_buf);
     return NULL;
@@ -575,6 +618,49 @@ PyObject *PyErr_SetFromWindowsErrWithUnicodeFilename(
 }
 #endif /* MS_WINDOWS */
 
+PyObject *
+PyErr_SetImportError(PyObject *msg, PyObject *name, PyObject *path)
+{
+    PyObject *args, *kwargs, *error;
+
+    if (msg == NULL)
+        return NULL;
+
+    args = PyTuple_New(1);
+    if (args == NULL)
+        return NULL;
+
+    kwargs = PyDict_New();
+    if (kwargs == NULL) {
+        Py_DECREF(args);
+        return NULL;
+    }
+
+    if (name == NULL) {
+        name = Py_None;
+    }
+
+    if (path == NULL) {
+        path = Py_None;
+    }
+
+    Py_INCREF(msg);
+    PyTuple_SET_ITEM(args, 0, msg);
+    PyDict_SetItemString(kwargs, "name", name);
+    PyDict_SetItemString(kwargs, "path", path);
+
+    error = PyObject_Call(PyExc_ImportError, args, kwargs);
+    if (error != NULL) {
+        PyErr_SetObject((PyObject *)Py_TYPE(error), error);
+        Py_DECREF(error);
+    }
+
+    Py_DECREF(args);
+    Py_DECREF(kwargs);
+
+    return NULL;
+}
+
 void
 _PyErr_BadInternalCall(const char *filename, int lineno)
 {
@@ -656,7 +742,7 @@ PyErr_NewException(const char *name, PyObject *base, PyObject *dict)
         if (bases == NULL)
             goto failure;
     }
-    /* Create a real new-style class. */
+    /* Create a real class. */
     result = PyObject_CallFunction((PyObject *)&PyType_Type, "sOO",
                                    dot+1, bases, dict);
   failure:
@@ -707,6 +793,7 @@ PyErr_NewExceptionWithDoc(const char *name, const char *doc,
 void
 PyErr_WriteUnraisable(PyObject *obj)
 {
+    _Py_IDENTIFIER(__module__);
     PyObject *f, *t, *v, *tb;
     PyErr_Fetch(&t, &v, &tb);
     f = PySys_GetObject("stderr");
@@ -723,7 +810,7 @@ PyErr_WriteUnraisable(PyObject *obj)
                     className = dot+1;
             }
 
-            moduleName = PyObject_GetAttrString(t, "__module__");
+            moduleName = _PyObject_GetAttrId(t, &PyId___module__);
             if (moduleName == NULL)
                 PyFile_WriteString("<unknown>", f);
             else {
@@ -774,6 +861,12 @@ void
 PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
 {
     PyObject *exc, *v, *tb, *tmp;
+    _Py_IDENTIFIER(filename);
+    _Py_IDENTIFIER(lineno);
+    _Py_IDENTIFIER(msg);
+    _Py_IDENTIFIER(offset);
+    _Py_IDENTIFIER(print_file_and_line);
+    _Py_IDENTIFIER(text);
 
     /* add attributes for the line number and filename for the error */
     PyErr_Fetch(&exc, &v, &tb);
@@ -784,7 +877,7 @@ PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
     if (tmp == NULL)
         PyErr_Clear();
     else {
-        if (PyObject_SetAttrString(v, "lineno", tmp))
+        if (_PyObject_SetAttrId(v, &PyId_lineno, tmp))
             PyErr_Clear();
         Py_DECREF(tmp);
     }
@@ -793,7 +886,7 @@ PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
         if (tmp == NULL)
             PyErr_Clear();
         else {
-            if (PyObject_SetAttrString(v, "offset", tmp))
+            if (_PyObject_SetAttrId(v, &PyId_offset, tmp))
                 PyErr_Clear();
             Py_DECREF(tmp);
         }
@@ -803,35 +896,35 @@ PyErr_SyntaxLocationEx(const char *filename, int lineno, int col_offset)
         if (tmp == NULL)
             PyErr_Clear();
         else {
-            if (PyObject_SetAttrString(v, "filename", tmp))
+            if (_PyObject_SetAttrId(v, &PyId_filename, tmp))
                 PyErr_Clear();
             Py_DECREF(tmp);
         }
 
         tmp = PyErr_ProgramText(filename, lineno);
         if (tmp) {
-            if (PyObject_SetAttrString(v, "text", tmp))
+            if (_PyObject_SetAttrId(v, &PyId_text, tmp))
                 PyErr_Clear();
             Py_DECREF(tmp);
         }
     }
-    if (PyObject_SetAttrString(v, "offset", Py_None)) {
+    if (_PyObject_SetAttrId(v, &PyId_offset, Py_None)) {
         PyErr_Clear();
     }
     if (exc != PyExc_SyntaxError) {
-        if (!PyObject_HasAttrString(v, "msg")) {
+        if (!_PyObject_HasAttrId(v, &PyId_msg)) {
             tmp = PyObject_Str(v);
             if (tmp) {
-                if (PyObject_SetAttrString(v, "msg", tmp))
+                if (_PyObject_SetAttrId(v, &PyId_msg, tmp))
                     PyErr_Clear();
                 Py_DECREF(tmp);
             } else {
                 PyErr_Clear();
             }
         }
-        if (!PyObject_HasAttrString(v, "print_file_and_line")) {
-            if (PyObject_SetAttrString(v, "print_file_and_line",
-                                       Py_None))
+        if (!_PyObject_HasAttrId(v, &PyId_print_file_and_line)) {
+            if (_PyObject_SetAttrId(v, &PyId_print_file_and_line,
+                                    Py_None))
                 PyErr_Clear();
         }
     }