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Forward-port of r52136,52138: a review of overflow-detecting code.

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* unified the way intobject, longobject and mystrtoul handle
  values around -sys.maxint-1.

* in general, trying to entierely avoid overflows in any computation
  involving signed ints or longs is extremely involved.  Fixed a few
  simple cases where a compiler might be too clever (but that's all
  guesswork).

* more overflow checks against bad data in marshal.c.

* 2.5 specific: fixed a number of places that were still confusing int
  and Py_ssize_t.  Some of them could potentially have caused
  "real-world" breakage.

* list.pop(x): fixing overflow issues on x was messy.  I just reverted
  to PyArg_ParseTuple("n"), which does the right thing.  (An obscure
  test was trying to give a Decimal to list.pop()... doesn't make
  sense any more IMHO)

* trying to write a few tests...
This commit is contained in:
Armin Rigo 2006-10-04 12:17:45 +00:00
parent 0d2f498a4c
commit 7ccbca93a2
19 changed files with 186 additions and 106 deletions
Download patch file Download diff file Expand all files Collapse all files

3
Python/errors.c
View file

@ -551,7 +551,8 @@ PyErr_NewException(char *name, PyObject *base, PyObject *dict)
goto failure;
}
if (PyDict_GetItemString(dict, "__module__") == NULL) {
modulename = PyString_FromStringAndSize(name, (int)(dot-name));
modulename = PyString_FromStringAndSize(name,
(Py_ssize_t)(dot-name));
if (modulename == NULL)
goto failure;
if (PyDict_SetItemString(dict, "__module__", modulename) != 0)

7
Python/getargs.c
View file

@ -815,7 +815,7 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
#endif
else
return converterr("string", arg, msgbuf, bufsize);
if ((int)strlen(*p) != PyString_Size(arg))
if ((Py_ssize_t)strlen(*p) != PyString_Size(arg))
return converterr("string without null bytes",
arg, msgbuf, bufsize);
}
@ -882,7 +882,7 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
format++;
}
else if (*p != NULL &&
(int)strlen(*p) != PyString_Size(arg))
(Py_ssize_t)strlen(*p) != PyString_Size(arg))
return converterr(
"string without null bytes or None",
arg, msgbuf, bufsize);
@ -1029,7 +1029,8 @@ convertsimple(PyObject *arg, const char **p_format, va_list *p_va, int flags,
PyMem_Free()ing it after usage
*/
if ((int)strlen(PyString_AS_STRING(s)) != size) {
if ((Py_ssize_t)strlen(PyString_AS_STRING(s))
!= size) {
Py_DECREF(s);
return converterr(
"(encoded string without NULL bytes)",

38
Python/marshal.c
View file

@ -546,6 +546,11 @@ r_object(RFILE *p)
int size;
PyLongObject *ob;
n = r_long(p);
if (n < -INT_MAX || n > INT_MAX) {
PyErr_SetString(PyExc_ValueError,
"bad marshal data");
return NULL;
}
size = n<0 ? -n : n;
ob = _PyLong_New(size);
if (ob == NULL)
@ -654,7 +659,7 @@ r_object(RFILE *p)
case TYPE_INTERNED:
case TYPE_STRING:
n = r_long(p);
if (n < 0) {
if (n < 0 || n > INT_MAX) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
@ -689,7 +694,7 @@ r_object(RFILE *p)
char *buffer;
n = r_long(p);
if (n < 0) {
if (n < 0 || n > INT_MAX) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
@ -710,7 +715,7 @@ r_object(RFILE *p)
case TYPE_TUPLE:
n = r_long(p);
if (n < 0) {
if (n < 0 || n > INT_MAX) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
@ -733,7 +738,7 @@ r_object(RFILE *p)
case TYPE_LIST:
n = r_long(p);
if (n < 0) {
if (n < 0 || n > INT_MAX) {
PyErr_SetString(PyExc_ValueError, "bad marshal data");
return NULL;
}
@ -831,10 +836,11 @@ r_object(RFILE *p)
v = NULL;
argcount = r_long(p);
nlocals = r_long(p);
stacksize = r_long(p);
flags = r_long(p);
/* XXX ignore long->int overflows for now */
argcount = (int)r_long(p);
nlocals = (int)r_long(p);
stacksize = (int)r_long(p);
flags = (int)r_long(p);
code = r_object(p);
if (code == NULL)
goto code_error;
@ -859,7 +865,7 @@ r_object(RFILE *p)
name = r_object(p);
if (name == NULL)
goto code_error;
firstlineno = r_long(p);
firstlineno = (int)r_long(p);
lnotab = r_object(p);
if (lnotab == NULL)
goto code_error;
@ -1031,10 +1037,16 @@ PyMarshal_WriteObjectToString(PyObject *x, int version)
wf.strings = (version > 0) ? PyDict_New() : NULL;
w_object(x, &wf);
Py_XDECREF(wf.strings);
if (wf.str != NULL)
_PyString_Resize(&wf.str,
(int) (wf.ptr -
PyString_AS_STRING((PyStringObject *)wf.str)));
if (wf.str != NULL) {
char *base = PyString_AS_STRING((PyStringObject *)wf.str);
if (wf.ptr - base > PY_SSIZE_T_MAX) {
Py_DECREF(wf.str);
PyErr_SetString(PyExc_OverflowError,
"too much marshall data for a string");
return NULL;
}
_PyString_Resize(&wf.str, (Py_ssize_t)(wf.ptr - base));
}
if (wf.error) {
Py_XDECREF(wf.str);
PyErr_SetString(PyExc_ValueError,

2
Python/modsupport.c
View file

@ -421,7 +421,7 @@ do_mkvalue(const char **p_format, va_list *p_va, int flags)
"string too long for Python string");
return NULL;
}
n = (int)m;
n = (Py_ssize_t)m;
}
v = PyString_FromStringAndSize(str, n);
}

12
Python/mystrtoul.c
View file

@ -195,13 +195,10 @@ overflowed:
return (unsigned long)-1;
}
/* Checking for overflow in PyOS_strtol is a PITA since C doesn't define
* anything about what happens when a signed integer operation overflows,
* and some compilers think they're doing you a favor by being "clever"
* then. Python assumes a 2's-complement representation, so that the bit
* pattern for the largest postive signed long is LONG_MAX, and for
* the smallest negative signed long is LONG_MAX + 1.
/* Checking for overflow in PyOS_strtol is a PITA; see comments
* about PY_ABS_LONG_MIN in longobject.c.
*/
#define PY_ABS_LONG_MIN (0-(unsigned long)LONG_MIN)
long
PyOS_strtol(char *str, char **ptr, int base)
@ -224,8 +221,7 @@ PyOS_strtol(char *str, char **ptr, int base)
if (sign == '-')
result = -result;
}
else if (sign == '-' && uresult == (unsigned long)LONG_MAX + 1) {
assert(LONG_MIN == -LONG_MAX-1);
else if (sign == '-' && uresult == PY_ABS_LONG_MIN) {
result = LONG_MIN;
}
else {

2
Python/sysmodule.c
View file

@ -1225,7 +1225,7 @@ makepathobject(char *path, int delim)
p = strchr(path, delim);
if (p == NULL)
p = strchr(path, '\0'); /* End of string */
w = PyString_FromStringAndSize(path, (int) (p - path));
w = PyString_FromStringAndSize(path, (Py_ssize_t) (p - path));
if (w == NULL) {
Py_DECREF(v);
return NULL;