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Trent Mick <trentm@activestate.com>: 

This patch fixes possible overflow in the use of
PyOS_GetLastModificationTime in getmtime.c and Python/import.c.

Currently PyOS_GetLastModificationTime returns a C long. This can
overflow on Win64 where sizeof(time_t) > sizeof(long). Besides it
should logically return a time_t anyway (this patch changes this).

As well, import.c uses PyOS_GetLastModificationTime for .pyc
timestamping.  There has been recent discussion about the .pyc header
format on python-dev.  This patch adds oveflow checking to import.c so
that an exception will be raised if the modification time
overflows. There are a few other minor 64-bit readiness changes made
to the module as well:

- size_t instead of int or long for function-local buffer and string
length variables

- one buffer overflow check was added (raises an exception on possible
overflow, this overflow chance exists on 32-bit platforms as well), no
other possible buffer overflows existed (from my analysis anyway)

Closes SourceForge patch #100509.
This commit is contained in:
Fred Drake 2000-06-30 16:18:57 +00:00
parent 4358b2c928
commit 4c82b2366f
2 changed files with 33 additions and 14 deletions
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3
Python/getmtime.c
View File

@ -33,13 +33,14 @@ PERFORMANCE OF THIS SOFTWARE.
/* (A separate file because this may be OS dependent) */
#include "Python.h"
#include "config.h"
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
long
time_t
PyOS_GetLastModificationTime(path, fp)
char *path;
FILE *fp;

44
Python/import.c
View File

@ -74,7 +74,7 @@ PERFORMANCE OF THIS SOFTWARE.
#endif
extern long PyOS_GetLastModificationTime(); /* In getmtime.c */
extern time_t PyOS_GetLastModificationTime(); /* In getmtime.c */
/* Magic word to reject .pyc files generated by other Python versions */
/* Change for each incompatible change */
@ -549,9 +549,9 @@ static char *
make_compiled_pathname(pathname, buf, buflen)
char *pathname;
char *buf;
int buflen;
size_t buflen;
{
int len;
size_t len;
len = strlen(pathname);
if (len+2 > buflen)
@ -732,7 +732,7 @@ load_source_module(name, pathname, fp)
char *pathname;
FILE *fp;
{
long mtime;
time_t mtime;
FILE *fpc;
char buf[MAXPATHLEN+1];
char *cpathname;
@ -740,7 +740,20 @@ load_source_module(name, pathname, fp)
PyObject *m;
mtime = PyOS_GetLastModificationTime(pathname, fp);
cpathname = make_compiled_pathname(pathname, buf, MAXPATHLEN+1);
if (mtime == -1)
return NULL;
#if SIZEOF_TIME_T > 4
/* Python's .pyc timestamp handling presumes that the timestamp fits
in 4 bytes. This will be fine until sometime in the year 2038,
when a 4-byte signed time_t will overflow.
*/
if (mtime >> 32) {
PyErr_SetString(PyExc_OverflowError,
"modification time overflows a 4 bytes");
return NULL;
}
#endif
cpathname = make_compiled_pathname(pathname, buf, (size_t)MAXPATHLEN+1);
if (cpathname != NULL &&
(fpc = check_compiled_module(pathname, mtime, cpathname))) {
co = read_compiled_module(cpathname, fpc);
@ -771,7 +784,7 @@ load_source_module(name, pathname, fp)
/* Forward */
static PyObject *load_module Py_PROTO((char *, FILE *, char *, int));
static struct filedescr *find_module Py_PROTO((char *, PyObject *,
char *, int, FILE **));
char *, size_t, FILE **));
static struct _frozen *find_frozen Py_PROTO((char *name));
/* Load a package and return its module object WITH INCREMENTED
@ -869,10 +882,11 @@ find_module(realname, path, buf, buflen, p_fp)
PyObject *path;
/* Output parameters: */
char *buf;
int buflen;
size_t buflen;
FILE **p_fp;
{
int i, npath, len, namelen;
int i, npath;
size_t len, namelen;
struct _frozen *f;
struct filedescr *fdp = NULL;
FILE *fp = NULL;
@ -882,6 +896,10 @@ find_module(realname, path, buf, buflen, p_fp)
static struct filedescr fd_package = {"", "", PKG_DIRECTORY};
char name[MAXPATHLEN+1];
if (strlen(realname) > MAXPATHLEN) {
PyErr_SetString(PyExc_OverflowError, "module name is too long");
return NULL;
}
strcpy(name, realname);
if (path != NULL && PyString_Check(path)) {
@ -933,7 +951,7 @@ find_module(realname, path, buf, buflen, p_fp)
if (len + 2 + namelen + MAXSUFFIXSIZE >= buflen)
continue; /* Too long */
strcpy(buf, PyString_AsString(v));
if ((int)strlen(buf) != len)
if (strlen(buf) != len)
continue; /* v contains '\0' */
#ifdef macintosh
#ifdef INTERN_STRINGS
@ -1181,8 +1199,8 @@ static int
find_init_module(buf)
char *buf;
{
int save_len = strlen(buf);
int i = save_len;
size_t save_len = strlen(buf);
size_t i = save_len;
struct stat statbuf;
if (save_len + 13 >= MAXPATHLEN)
@ -1577,7 +1595,7 @@ get_parent(globals, buf, p_buflen)
else {
char *start = PyString_AS_STRING(modname);
char *lastdot = strrchr(start, '.');
int len;
size_t len;
if (lastdot == NULL)
return Py_None;
len = lastdot - start;
@ -1612,7 +1630,7 @@ load_next(mod, altmod, p_name, buf, p_buflen)
{
char *name = *p_name;
char *dot = strchr(name, '.');
int len;
size_t len;
char *p;
PyObject *result;