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Michael Hudson <mwh21@cam.ac.uk>:

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As I really do not have anything better to do at the moment, I have written
a patch to Python/marshal.c that prevents Python dumping core when trying
to marshal stack bustingly deep (or recursive) data structure.

It just throws an exception; even slightly clever handling of recursive
data is what pickle is for...

[Fred Drake:]  Moved magic constant 5000 to a #define.

This closes SourceForge patch #100645.
This commit is contained in:
Fred Drake 2000-06-28 18:47:56 +00:00
parent 7833447f8f
commit 6da0b9148c
1 changed files with 22 additions and 3 deletions
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25
Python/marshal.c
View file

@ -39,6 +39,12 @@ PERFORMANCE OF THIS SOFTWARE.
#include "compile.h" #include "compile.h"
#include "marshal.h" #include "marshal.h"
/* High water mark to determine when the marshalled object is dangerously deep
* and risks coring the interpreter. When the object stack gets this deep,
* raise an exception instead of continuing.
*/
#define MAX_MARSHAL_STACK_DEPTH 5000
#define TYPE_NULL '0' #define TYPE_NULL '0'
#define TYPE_NONE 'N' #define TYPE_NONE 'N'
#define TYPE_ELLIPSIS '.' #define TYPE_ELLIPSIS '.'
@ -58,6 +64,7 @@ PERFORMANCE OF THIS SOFTWARE.
typedef struct { typedef struct {
FILE *fp; FILE *fp;
int error; int error;
int depth;
/* If fp == NULL, the following are valid: */ /* If fp == NULL, the following are valid: */
PyObject *str; PyObject *str;
char *ptr; char *ptr;
@ -144,8 +151,13 @@ w_object(v, p)
{ {
int i, n; int i, n;
PyBufferProcs *pb; PyBufferProcs *pb;
p->depth++;
if (v == NULL) { if (p->depth > MAX_MARSHAL_STACK_DEPTH) {
p->error = 2;
}
else if (v == NULL) {
w_byte(TYPE_NULL, p); w_byte(TYPE_NULL, p);
} }
else if (v == Py_None) { else if (v == Py_None) {
@ -301,6 +313,7 @@ PyMarshal_WriteLongToFile(x, fp)
WFILE wf; WFILE wf;
wf.fp = fp; wf.fp = fp;
wf.error = 0; wf.error = 0;
wf.depth = 0;
w_long(x, &wf); w_long(x, &wf);
} }
@ -690,6 +703,7 @@ PyMarshal_WriteObjectToString(x) /* wrs_object() */
wf.ptr = PyString_AS_STRING((PyStringObject *)wf.str); wf.ptr = PyString_AS_STRING((PyStringObject *)wf.str);
wf.end = wf.ptr + PyString_Size(wf.str); wf.end = wf.ptr + PyString_Size(wf.str);
wf.error = 0; wf.error = 0;
wf.depth = 0;
w_object(x, &wf); w_object(x, &wf);
if (wf.str != NULL) if (wf.str != NULL)
_PyString_Resize(&wf.str, _PyString_Resize(&wf.str,
@ -697,7 +711,9 @@ PyMarshal_WriteObjectToString(x) /* wrs_object() */
PyString_AS_STRING((PyStringObject *)wf.str))); PyString_AS_STRING((PyStringObject *)wf.str)));
if (wf.error) { if (wf.error) {
Py_XDECREF(wf.str); Py_XDECREF(wf.str);
PyErr_SetString(PyExc_ValueError, "unmarshallable object"); PyErr_SetString(PyExc_ValueError,
(wf.error==1)?"unmarshallable object"
:"object too deeply nested to marshal");
return NULL; return NULL;
} }
return wf.str; return wf.str;
@ -724,9 +740,12 @@ marshal_dump(self, args)
wf.str = NULL; wf.str = NULL;
wf.ptr = wf.end = NULL; wf.ptr = wf.end = NULL;
wf.error = 0; wf.error = 0;
wf.depth = 0;
w_object(x, &wf); w_object(x, &wf);
if (wf.error) { if (wf.error) {
PyErr_SetString(PyExc_ValueError, "unmarshallable object"); PyErr_SetString(PyExc_ValueError,
(wf.error==1)?"unmarshallable object"
:"object too deeply nested to marshal");
return NULL; return NULL;
} }
Py_INCREF(Py_None); Py_INCREF(Py_None);