Add missing checks for failures in calls to PyUnicode_AsUTF8String.

Previously a seg fault could occur when passing invalid UTF8 strings (low
surrogates), eg passing u"\udcff" to the C layer (Python 3).

Lib/python/pyerrors.swg

@@ -53,14 +53,17 @@ SWIG_Python_AddErrorMsg(const char* mesg)
   PyObject *value = 0;
   PyObject *traceback = 0;
 
-  if (PyErr_Occurred()) PyErr_Fetch(&type, &value, &traceback);
+  if (PyErr_Occurred())
+    PyErr_Fetch(&type, &value, &traceback);
   if (value) {
-    char *tmp;
     PyObject *old_str = PyObject_Str(value);
+    const char *tmp = SWIG_Python_str_AsChar(old_str);
     PyErr_Clear();
     Py_XINCREF(type);
-
-    PyErr_Format(type, "%s %s", tmp = SWIG_Python_str_AsChar(old_str), mesg);
+    if (tmp)
+      PyErr_Format(type, "%s %s", tmp, mesg);
+    else
+      PyErr_Format(type, "%s", mesg);
     SWIG_Python_str_DelForPy3(tmp);
     Py_DECREF(old_str);
     Py_DECREF(value);

Lib/python/pyhead.swg

@@ -38,14 +38,16 @@ SWIGINTERN char*
 SWIG_Python_str_AsChar(PyObject *str)
 {
 #if PY_VERSION_HEX >= 0x03000000
-  char *cstr;
-  char *newstr;
-  Py_ssize_t len;
+  char *newstr = 0;
   str = PyUnicode_AsUTF8String(str);
-  PyBytes_AsStringAndSize(str, &cstr, &len);
-  newstr = (char *) malloc(len+1);
-  memcpy(newstr, cstr, len+1);
-  Py_XDECREF(str);
+  if (str) {
+    char *cstr;
+    Py_ssize_t len;
+    PyBytes_AsStringAndSize(str, &cstr, &len);
+    newstr = (char *) malloc(len+1);
+    memcpy(newstr, cstr, len+1);
+    Py_XDECREF(str);
+  }
   return newstr;
 #else
   return PyString_AsString(str);

Lib/python/pyinit.swg

@@ -84,10 +84,10 @@ swig_varlink_str(swig_varlinkobject *v) {
 
 SWIGINTERN int
 swig_varlink_print(swig_varlinkobject *v, FILE *fp, int SWIGUNUSEDPARM(flags)) {
-  char *tmp;
   PyObject *str = swig_varlink_str(v);
+  const char *tmp = SWIG_Python_str_AsChar(str);
   fprintf(fp,"Swig global variables ");
-  fprintf(fp,"%s\n", tmp = SWIG_Python_str_AsChar(str));
+  fprintf(fp,"%s\n", tmp ? tmp : "Invalid global variable");
   SWIG_Python_str_DelForPy3(tmp);
   Py_DECREF(str);
   return 0;

Lib/python/pyrun.swg

@@ -1672,14 +1672,16 @@ SWIG_Python_AddErrMesg(const char* mesg, int infront)
     PyObject *traceback = 0;
     PyErr_Fetch(&type, &value, &traceback);
     if (value) {
-      char *tmp;
       PyObject *old_str = PyObject_Str(value);
+      const char *tmp = SWIG_Python_str_AsChar(old_str);
+      if (!tmp)
+        tmp = "Invalid error message";
       Py_XINCREF(type);
       PyErr_Clear();
       if (infront) {
-	PyErr_Format(type, "%s %s", mesg, tmp = SWIG_Python_str_AsChar(old_str));
+	PyErr_Format(type, "%s %s", mesg, tmp);
       } else {
-	PyErr_Format(type, "%s %s", tmp = SWIG_Python_str_AsChar(old_str), mesg);
+	PyErr_Format(type, "%s %s", tmp, mesg);
       }
       SWIG_Python_str_DelForPy3(tmp);
       Py_DECREF(old_str);
@@ -1805,6 +1807,8 @@ SWIG_Python_NonDynamicSetAttr(PyObject *obj, PyObject *name, PyObject *value) {
       Py_INCREF(name);
     } else {
       encoded_name = PyUnicode_AsUTF8String(name);
+      if (!encoded_name)
+        return -1;
     }
     PyErr_Format(PyExc_AttributeError, "'%.100s' object has no attribute '%.200s'", tp->tp_name, PyString_AsString(encoded_name));
     Py_DECREF(encoded_name);

Lib/python/pystrings.swg

@@ -16,6 +16,7 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
 %#endif
   {
     char *cstr; Py_ssize_t len;
+    int ret = SWIG_OK;
 %#if PY_VERSION_HEX>=0x03000000
 %#if !defined(SWIG_PYTHON_STRICT_BYTE_CHAR)
     if (!alloc && cptr) {
@@ -26,7 +27,10 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
         return SWIG_RuntimeError;
     }
     obj = PyUnicode_AsUTF8String(obj);
-    if(alloc) *alloc = SWIG_NEWOBJ;
+    if (!obj)
+      return SWIG_TypeError;
+    if (alloc)
+      *alloc = SWIG_NEWOBJ;
 %#endif
     PyBytes_AsStringAndSize(obj, &cstr, &len);
 %#else
@@ -64,6 +68,8 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
 %#endif
 %#else
 	*cptr = SWIG_Python_str_AsChar(obj);
+        if (!*cptr)
+          ret = SWIG_TypeError;
 %#endif
       }
     }
@@ -71,7 +77,7 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
 %#if PY_VERSION_HEX>=0x03000000 && !defined(SWIG_PYTHON_STRICT_BYTE_CHAR)
     Py_XDECREF(obj);
 %#endif
-    return SWIG_OK;
+    return ret;
   } else {
 %#if defined(SWIG_PYTHON_2_UNICODE)
 %#if defined(SWIG_PYTHON_STRICT_BYTE_CHAR)
@@ -84,6 +90,8 @@ SWIG_AsCharPtrAndSize(PyObject *obj, char** cptr, size_t* psize, int *alloc)
         return SWIG_RuntimeError;
       }
       obj = PyUnicode_AsUTF8String(obj);
+      if (!obj)
+        return SWIG_TypeError;
       if (PyString_AsStringAndSize(obj, &cstr, &len) != -1) {
         if (cptr) {
           if (alloc) *alloc = SWIG_NEWOBJ;