Skip to content

Commit

Permalink
bpo-20104: Fix leaks and errors in new os.posix_spawn (GH-5418)
Browse files Browse the repository at this point in the history 
* Fix memory leaks and error handling in posix spawn
* Improve error handling when destroying the file_actions object
* Py_DECREF the result of PySequence_Fast on error
* Handle uninitialized pid
* Use OSError if file actions fails to initialize
* Move _file_actions to outer scope to avoid undefined behaviour
* Remove HAVE_POSIX_SPAWN define in Modules/posixmodule.c
* Unshadow exception and clean error message
  • Loading branch information
@pablogsal @gpshead
pablogsal authored and gpshead committed Jan 29, 2018
1 parent c65ef77 commit 0cd6bca
Showing 1 changed file with 66 additions and 52 deletions.
118 changes: 66 additions & 52 deletions Modules/posixmodule.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -176,14 +176,6 @@ corresponding Unix manual entries for more information on calls.");
#else
/* Unix functions that the configure script doesn't check for */
#define HAVE_EXECV 1
/* bpo-32705: Current Android does not have posix_spawn
* Most likely posix_spawn will be available in next Android version (Android
* P, API 28). Need revisit then. See
* https://android-review.googlesource.com/c/platform/bionic/+/504842
**/
#ifndef __ANDROID__
#define HAVE_POSIX_SPAWN 1
#endif
#define HAVE_FORK 1
#if defined(__USLC__) && defined(__SCO_VERSION__) /* SCO UDK Compiler */
#define HAVE_FORK1 1
Expand Down Expand Up @@ -5139,17 +5131,22 @@ os_posix_spawn_impl(PyObject *module, path_t *path, PyObject *argv,
/*[clinic end generated code: output=d023521f541c709c input=0ec9f1cfdc890be5]*/
{
EXECV_CHAR **argvlist = NULL;
EXECV_CHAR **envlist;
EXECV_CHAR **envlist = NULL;
posix_spawn_file_actions_t _file_actions;
posix_spawn_file_actions_t *file_actionsp = NULL;
Py_ssize_t argc, envc;
PyObject* result = NULL;
PyObject* seq = NULL;


/* posix_spawn has three arguments: (path, argv, env), where
argv is a list or tuple of strings and env is a dictionary
like posix.environ. */

if (!PySequence_Check(argv)){
if (!PySequence_Check(argv)) {
PyErr_SetString(PyExc_TypeError,
"posix_spawn: argv must be a tuple or list");
goto fail;
goto exit;
}
argc = PySequence_Size(argv);
if (argc < 1) {
Expand All @@ -5160,50 +5157,47 @@ os_posix_spawn_impl(PyObject *module, path_t *path, PyObject *argv,
if (!PyMapping_Check(env)) {
PyErr_SetString(PyExc_TypeError,
"posix_spawn: environment must be a mapping object");
goto fail;
goto exit;
}

argvlist = parse_arglist(argv, &argc);
if (argvlist == NULL) {
goto fail;
goto exit;
}
if (!argvlist[0][0]) {
PyErr_SetString(PyExc_ValueError,
"posix_spawn: argv first element cannot be empty");
goto fail;
goto exit;
}

envlist = parse_envlist(env, &envc);
if (envlist == NULL)
goto fail;
if (envlist == NULL) {
goto exit;
}

pid_t pid;
posix_spawn_file_actions_t *file_actionsp = NULL;
if (file_actions != NULL && file_actions != Py_None){
posix_spawn_file_actions_t _file_actions;
if (file_actions != NULL && file_actions != Py_None) {
if(posix_spawn_file_actions_init(&_file_actions) != 0){
PyErr_SetString(PyExc_TypeError,
PyErr_SetString(PyExc_OSError,
"Error initializing file actions");
goto fail;
goto exit;
}


file_actionsp = &_file_actions;


PyObject* seq = PySequence_Fast(file_actions, "file_actions must be a sequence");
if(seq == NULL){
goto fail;
seq = PySequence_Fast(file_actions, "file_actions must be a sequence");
if(seq == NULL) {
goto exit;
}
PyObject* file_actions_obj;
PyObject* mode_obj;

for (int i = 0; i < PySequence_Fast_GET_SIZE(seq); ++i) {
file_actions_obj = PySequence_Fast_GET_ITEM(seq, i);

if(!PySequence_Check(file_actions_obj) | !PySequence_Size(file_actions_obj)){
if(!PySequence_Check(file_actions_obj) | !PySequence_Size(file_actions_obj)) {
PyErr_SetString(PyExc_TypeError,"Each file_action element must be a non empty sequence");
goto fail;
goto exit;
}


Expand All @@ -5215,83 +5209,103 @@ os_posix_spawn_impl(PyObject *module, path_t *path, PyObject *argv,
switch(mode) {

case POSIX_SPAWN_OPEN:
if(PySequence_Size(file_actions_obj) != 5){
if(PySequence_Size(file_actions_obj) != 5) {
PyErr_SetString(PyExc_TypeError,"A open file_action object must have 5 elements");
goto fail;
goto exit;
}

long open_fd = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 1));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
const char* open_path = PyUnicode_AsUTF8(PySequence_GetItem(file_actions_obj, 2));
if(open_path == NULL){
goto fail;
if(open_path == NULL) {
goto exit;
}
long open_oflag = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 3));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
long open_mode = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 4));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
if(posix_spawn_file_actions_addopen(file_actionsp, open_fd, open_path, open_oflag, open_mode)) {
PyErr_SetString(PyExc_OSError,"Failed to add open file action");
goto exit;
}
posix_spawn_file_actions_addopen(file_actionsp, open_fd, open_path, open_oflag, open_mode);

break;

case POSIX_SPAWN_CLOSE:
if(PySequence_Size(file_actions_obj) != 2){
PyErr_SetString(PyExc_TypeError,"A close file_action object must have 2 elements");
goto fail;
goto exit;
}

long close_fd = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 1));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
if(posix_spawn_file_actions_addclose(file_actionsp, close_fd)) {
PyErr_SetString(PyExc_OSError,"Failed to add close file action");
goto exit;
}
posix_spawn_file_actions_addclose(file_actionsp, close_fd);
break;

case POSIX_SPAWN_DUP2:
if(PySequence_Size(file_actions_obj) != 3){
PyErr_SetString(PyExc_TypeError,"A dup2 file_action object must have 3 elements");
goto fail;
goto exit;
}

long fd1 = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 1));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
long fd2 = PyLong_AsLong(PySequence_GetItem(file_actions_obj, 2));
if(PyErr_Occurred()) {
goto fail;
goto exit;
}
if(posix_spawn_file_actions_adddup2(file_actionsp, fd1, fd2)) {
PyErr_SetString(PyExc_OSError,"Failed to add dup2 file action");
goto exit;
}
posix_spawn_file_actions_adddup2(file_actionsp, fd1, fd2);
break;

default:
PyErr_SetString(PyExc_TypeError,"Unknown file_actions identifier");
goto fail;
goto exit;
}
}
Py_DECREF(seq);
}
}

_Py_BEGIN_SUPPRESS_IPH
posix_spawn(&pid, path->narrow, file_actionsp, NULL, argvlist, envlist);
return PyLong_FromPid(pid);
int err_code = posix_spawn(&pid, path->narrow, file_actionsp, NULL, argvlist, envlist);
_Py_END_SUPPRESS_IPH
if(err_code) {
PyErr_SetString(PyExc_OSError,"posix_spawn call failed");
goto exit;
}
result = PyLong_FromPid(pid);

path_error(path);
exit:

free_string_array(envlist, envc);
Py_XDECREF(seq);

fail:
if(file_actionsp) {
posix_spawn_file_actions_destroy(file_actionsp);
}

if (envlist) {
free_string_array(envlist, envc);
}

if (argvlist) {
free_string_array(argvlist, argc);
}
return NULL;

return result;


}
Expand Down

0 comments on commit 0cd6bca

Please sign in to comment.