cpython/Modules/syslogmodule.c
Miss Islington (bot) 820904eab2
gh-95041: Fix several minor issues in syslog.openlog() (GH-95058) (GH-95261)
* syslog_get_argv() swallows exceptions, but not in all cases.
* if ident is non UTF-8 encodable, syslog.openlog() fails after setting the
  global reference to ident. Now the C string saved internally in the previous
  call to openlog() points to the freed memory.
* PySys_Audit() can crash if ident is NULL.
* There may be a race condition with syslog.syslog(), because the global
  reference to ident is decrefed before setting the new value.
* Possible use of freed memory if syslog.openlog() is called while
  the GIL is released in syslog.syslog().
(cherry picked from commit 68c555a50a)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
2022-07-26 12:21:48 +02:00

367 lines
10 KiB
C

/***********************************************************
Copyright 1994 by Lance Ellinghouse,
Cathedral City, California Republic, United States of America.
All Rights Reserved
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the name of Lance Ellinghouse
not be used in advertising or publicity pertaining to distribution
of the software without specific, written prior permission.
LANCE ELLINGHOUSE DISCLAIMS ALL WARRANTIES WITH REGARD TO
THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
FITNESS, IN NO EVENT SHALL LANCE ELLINGHOUSE BE LIABLE FOR ANY SPECIAL,
INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING
FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION
WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
******************************************************************/
/******************************************************************
Revision history:
2010/04/20 (Sean Reifschneider)
- Use basename(sys.argv[0]) for the default "ident".
- Arguments to openlog() are now keyword args and are all optional.
- syslog() calls openlog() if it hasn't already been called.
1998/04/28 (Sean Reifschneider)
- When facility not specified to syslog() method, use default from openlog()
(This is how it was claimed to work in the documentation)
- Potential resource leak of o_ident, now cleaned up in closelog()
- Minor comment accuracy fix.
95/06/29 (Steve Clift)
- Changed arg parsing to use PyArg_ParseTuple.
- Added PyErr_Clear() call(s) where needed.
- Fix core dumps if user message contains format specifiers.
- Change openlog arg defaults to match normal syslog behavior.
- Plug memory leak in openlog().
- Fix setlogmask() to return previous mask value.
******************************************************************/
/* syslog module */
#include "Python.h"
#include "osdefs.h" // SEP
#include <syslog.h>
/* only one instance, only one syslog, so globals should be ok */
static PyObject *S_ident_o = NULL; /* identifier, held by openlog() */
static char S_log_open = 0;
static PyObject *
syslog_get_argv(void)
{
/* Figure out what to use for as the program "ident" for openlog().
* This swallows exceptions and continues rather than failing out,
* because the syslog module can still be used because openlog(3)
* is optional.
*/
Py_ssize_t argv_len, scriptlen;
PyObject *scriptobj;
Py_ssize_t slash;
PyObject *argv = PySys_GetObject("argv");
if (argv == NULL) {
return(NULL);
}
argv_len = PyList_Size(argv);
if (argv_len == -1) {
PyErr_Clear();
return(NULL);
}
if (argv_len == 0) {
return(NULL);
}
scriptobj = PyList_GetItem(argv, 0);
if (scriptobj == NULL) {
PyErr_Clear();
return NULL;
}
if (!PyUnicode_Check(scriptobj)) {
return(NULL);
}
scriptlen = PyUnicode_GET_LENGTH(scriptobj);
if (scriptlen == 0) {
return(NULL);
}
slash = PyUnicode_FindChar(scriptobj, SEP, 0, scriptlen, -1);
if (slash == -2) {
PyErr_Clear();
return NULL;
}
if (slash != -1) {
return PyUnicode_Substring(scriptobj, slash + 1, scriptlen);
} else {
Py_INCREF(scriptobj);
return(scriptobj);
}
}
static PyObject *
syslog_openlog(PyObject * self, PyObject * args, PyObject *kwds)
{
long logopt = 0;
long facility = LOG_USER;
PyObject *ident = NULL;
static char *keywords[] = {"ident", "logoption", "facility", 0};
const char *ident_str = NULL;
if (!PyArg_ParseTupleAndKeywords(args, kwds,
"|Ull:openlog", keywords, &ident, &logopt, &facility))
return NULL;
if (ident) {
Py_INCREF(ident);
}
else {
/* get sys.argv[0] or NULL if we can't for some reason */
ident = syslog_get_argv();
}
/* At this point, ident should be INCREF()ed. openlog(3) does not
* make a copy, and syslog(3) later uses it. We can't garbagecollect it.
* If NULL, just let openlog figure it out (probably using C argv[0]).
*/
if (ident) {
ident_str = PyUnicode_AsUTF8(ident);
if (ident_str == NULL) {
Py_DECREF(ident);
return NULL;
}
}
if (PySys_Audit("syslog.openlog", "Oll", ident ? ident : Py_None, logopt, facility) < 0) {
Py_DECREF(ident);
return NULL;
}
openlog(ident_str, logopt, facility);
S_log_open = 1;
Py_XSETREF(S_ident_o, ident);
Py_RETURN_NONE;
}
static PyObject *
syslog_syslog(PyObject * self, PyObject * args)
{
PyObject *message_object;
const char *message;
int priority = LOG_INFO;
if (!PyArg_ParseTuple(args, "iU;[priority,] message string",
&priority, &message_object)) {
PyErr_Clear();
if (!PyArg_ParseTuple(args, "U;[priority,] message string",
&message_object))
return NULL;
}
message = PyUnicode_AsUTF8(message_object);
if (message == NULL)
return NULL;
if (PySys_Audit("syslog.syslog", "is", priority, message) < 0) {
return NULL;
}
/* if log is not opened, open it now */
if (!S_log_open) {
PyObject *openargs;
/* Continue even if PyTuple_New fails, because openlog(3) is optional.
* So, we can still do logging in the unlikely event things are so hosed
* that we can't do this tuple.
*/
if ((openargs = PyTuple_New(0))) {
PyObject *openlog_ret = syslog_openlog(self, openargs, NULL);
Py_XDECREF(openlog_ret);
Py_DECREF(openargs);
}
}
/* Incref ident, because it can be decrefed if syslog.openlog() is
* called when the GIL is released.
*/
PyObject *ident = S_ident_o;
Py_XINCREF(ident);
Py_BEGIN_ALLOW_THREADS;
syslog(priority, "%s", message);
Py_END_ALLOW_THREADS;
Py_XDECREF(ident);
Py_RETURN_NONE;
}
static PyObject *
syslog_closelog(PyObject *self, PyObject *unused)
{
if (PySys_Audit("syslog.closelog", NULL) < 0) {
return NULL;
}
if (S_log_open) {
closelog();
Py_CLEAR(S_ident_o);
S_log_open = 0;
}
Py_RETURN_NONE;
}
static PyObject *
syslog_setlogmask(PyObject *self, PyObject *args)
{
long maskpri, omaskpri;
if (!PyArg_ParseTuple(args, "l;mask for priority", &maskpri))
return NULL;
if (PySys_Audit("syslog.setlogmask", "(O)", args ? args : Py_None) < 0) {
return NULL;
}
omaskpri = setlogmask(maskpri);
return PyLong_FromLong(omaskpri);
}
static PyObject *
syslog_log_mask(PyObject *self, PyObject *args)
{
long mask;
long pri;
if (!PyArg_ParseTuple(args, "l:LOG_MASK", &pri))
return NULL;
mask = LOG_MASK(pri);
return PyLong_FromLong(mask);
}
static PyObject *
syslog_log_upto(PyObject *self, PyObject *args)
{
long mask;
long pri;
if (!PyArg_ParseTuple(args, "l:LOG_UPTO", &pri))
return NULL;
mask = LOG_UPTO(pri);
return PyLong_FromLong(mask);
}
/* List of functions defined in the module */
static PyMethodDef syslog_methods[] = {
{"openlog", _PyCFunction_CAST(syslog_openlog), METH_VARARGS | METH_KEYWORDS},
{"closelog", syslog_closelog, METH_NOARGS},
{"syslog", syslog_syslog, METH_VARARGS},
{"setlogmask", syslog_setlogmask, METH_VARARGS},
{"LOG_MASK", syslog_log_mask, METH_VARARGS},
{"LOG_UPTO", syslog_log_upto, METH_VARARGS},
{NULL, NULL, 0}
};
static int
syslog_exec(PyObject *module)
{
#define ADD_INT_MACRO(module, macro) \
do { \
if (PyModule_AddIntConstant(module, #macro, macro) < 0) { \
return -1; \
} \
} while (0)
/* Priorities */
ADD_INT_MACRO(module, LOG_EMERG);
ADD_INT_MACRO(module, LOG_ALERT);
ADD_INT_MACRO(module, LOG_CRIT);
ADD_INT_MACRO(module, LOG_ERR);
ADD_INT_MACRO(module, LOG_WARNING);
ADD_INT_MACRO(module, LOG_NOTICE);
ADD_INT_MACRO(module, LOG_INFO);
ADD_INT_MACRO(module, LOG_DEBUG);
/* openlog() option flags */
ADD_INT_MACRO(module, LOG_PID);
ADD_INT_MACRO(module, LOG_CONS);
ADD_INT_MACRO(module, LOG_NDELAY);
#ifdef LOG_ODELAY
ADD_INT_MACRO(module, LOG_ODELAY);
#endif
#ifdef LOG_NOWAIT
ADD_INT_MACRO(module, LOG_NOWAIT);
#endif
#ifdef LOG_PERROR
ADD_INT_MACRO(module, LOG_PERROR);
#endif
/* Facilities */
ADD_INT_MACRO(module, LOG_KERN);
ADD_INT_MACRO(module, LOG_USER);
ADD_INT_MACRO(module, LOG_MAIL);
ADD_INT_MACRO(module, LOG_DAEMON);
ADD_INT_MACRO(module, LOG_AUTH);
ADD_INT_MACRO(module, LOG_LPR);
ADD_INT_MACRO(module, LOG_LOCAL0);
ADD_INT_MACRO(module, LOG_LOCAL1);
ADD_INT_MACRO(module, LOG_LOCAL2);
ADD_INT_MACRO(module, LOG_LOCAL3);
ADD_INT_MACRO(module, LOG_LOCAL4);
ADD_INT_MACRO(module, LOG_LOCAL5);
ADD_INT_MACRO(module, LOG_LOCAL6);
ADD_INT_MACRO(module, LOG_LOCAL7);
#ifndef LOG_SYSLOG
#define LOG_SYSLOG LOG_DAEMON
#endif
#ifndef LOG_NEWS
#define LOG_NEWS LOG_MAIL
#endif
#ifndef LOG_UUCP
#define LOG_UUCP LOG_MAIL
#endif
#ifndef LOG_CRON
#define LOG_CRON LOG_DAEMON
#endif
ADD_INT_MACRO(module, LOG_SYSLOG);
ADD_INT_MACRO(module, LOG_CRON);
ADD_INT_MACRO(module, LOG_UUCP);
ADD_INT_MACRO(module, LOG_NEWS);
#ifdef LOG_AUTHPRIV
ADD_INT_MACRO(module, LOG_AUTHPRIV);
#endif
return 0;
}
static PyModuleDef_Slot syslog_slots[] = {
{Py_mod_exec, syslog_exec},
{0, NULL}
};
/* Initialization function for the module */
static struct PyModuleDef syslogmodule = {
PyModuleDef_HEAD_INIT,
.m_name = "syslog",
.m_size = 0,
.m_methods = syslog_methods,
.m_slots = syslog_slots,
};
PyMODINIT_FUNC
PyInit_syslog(void)
{
return PyModuleDef_Init(&syslogmodule);
}