Patch some corner-case bugs in pl/python.

Dave Malcolm of Red Hat is working on a static code analysis tool for
Python-related C code.  It reported a number of problems in plpython,
most of which were failures to check for NULL results from object-creation
functions, so would only be an issue in very-low-memory situations.

Patch in HEAD and 9.1.  We could go further back but it's not clear that
these issues are important enough to justify the work.

Jan Urbański

diff --git a/src/pl/plpython/plpython.c b/src/pl/plpython/plpython.c
index 530b5f03521ff1bfbf679f82b8ec1619cd4055c7..a3c8e5f0f0d16d1a465ca7930b5e7c51ccba1116 100644 (file)
--- a/src/pl/plpython/plpython.c
+++ b/src/pl/plpython/plpython.c
@@ -2345,6 +2345,8 @@ PLyList_FromArray(PLyDatumToOb *arg, Datum d)
        length = ARR_DIMS(array)[0];
        lbound = ARR_LBOUND(array)[0];
        list = PyList_New(length);
+       if (list == NULL)
+               PLy_elog(ERROR, "could not create new list");
 
        for (i = 0; i < length; i++)
        {
@@ -3664,7 +3666,7 @@ PLy_spi_execute_query(char *query, long limit)
        int                     rv;
        volatile MemoryContext oldcontext;
        volatile ResourceOwner oldowner;
-       PyObject   *ret;
+       PyObject   *ret = NULL;
 
        oldcontext = CurrentMemoryContext;
        oldowner = CurrentResourceOwner;
@@ -3727,6 +3729,7 @@ PLy_spi_execute_query(char *query, long limit)
 
        if (rv < 0)
        {
+               Py_XDECREF(ret);
                PLy_exception_set(PLy_exc_spi_error,
                                                  "SPI_execute failed: %s",
                                                  SPI_result_code_string(rv));
@@ -3967,7 +3970,13 @@ PLy_generate_spi_exceptions(PyObject *mod, PyObject *base)
                PyObject   *sqlstate;
                PyObject   *dict = PyDict_New();
 
+               if (dict == NULL)
+                       PLy_elog(ERROR, "could not generate SPI exceptions");
+
                sqlstate = PyString_FromString(unpack_sql_state(exception_map[i].sqlstate));
+               if (sqlstate == NULL)
+                       PLy_elog(ERROR, "could not generate SPI exceptions");
+
                PyDict_SetItemString(dict, "sqlstate", sqlstate);
                Py_DECREF(sqlstate);
                exc = PyErr_NewException(exception_map[i].name, base, dict);
@@ -4008,6 +4017,11 @@ PLy_add_exceptions(PyObject *plpy)
        PLy_exc_fatal = PyErr_NewException("plpy.Fatal", NULL, NULL);
        PLy_exc_spi_error = PyErr_NewException("plpy.SPIError", NULL, NULL);
 
+       if (PLy_exc_error == NULL ||
+               PLy_exc_fatal == NULL ||
+               PLy_exc_spi_error == NULL)
+               PLy_elog(ERROR, "could not create the base SPI exceptions");
+
        Py_INCREF(PLy_exc_error);
        PyModule_AddObject(plpy, "Error", PLy_exc_error);
        Py_INCREF(PLy_exc_fatal);
@@ -4124,6 +4138,8 @@ PLy_init_interp(void)
        Py_INCREF(mainmod);
        PLy_interp_globals = PyModule_GetDict(mainmod);
        PLy_interp_safe_globals = PyDict_New();
+       if (PLy_interp_safe_globals == NULL)
+               PLy_elog(ERROR, "could not create globals");
        PyDict_SetItemString(PLy_interp_globals, "GD", PLy_interp_safe_globals);
        Py_DECREF(mainmod);
        if (PLy_interp_globals == NULL || PyErr_Occurred())
@@ -4164,9 +4180,11 @@ PLy_init_plpy(void)
        main_mod = PyImport_AddModule("__main__");
        main_dict = PyModule_GetDict(main_mod);
        plpy_mod = PyImport_AddModule("plpy");
+       if (plpy_mod == NULL)
+               PLy_elog(ERROR, "could not initialize plpy");
        PyDict_SetItemString(main_dict, "plpy", plpy_mod);
        if (PyErr_Occurred())
-               elog(ERROR, "could not initialize plpy");
+               PLy_elog(ERROR, "could not initialize plpy");
 }
 
 /* the python interface to the elog function
@@ -4232,7 +4250,8 @@ PLy_output(volatile int level, PyObject *self, PyObject *args)
                 */
                PyObject   *o;
 
-               PyArg_UnpackTuple(args, "plpy.elog", 1, 1, &o);
+               if (!PyArg_UnpackTuple(args, "plpy.elog", 1, 1, &o))
+                       PLy_elog(ERROR, "could not unpack arguments in plpy.elog");
                so = PyObject_Str(o);
        }
        else
@@ -4554,6 +4573,10 @@ get_source_line(const char *src, int lineno)
        const char *next = src;
        int                     current = 0;
 
+       /* sanity check */
+       if (lineno <= 0)
+               return NULL;
+
        while (current < lineno)
        {
                s = next;