[Python-checkins] r67198 - in python/branches/release24-maint: Misc/NEWS Python/mysnprintf.c
matthias.klose
python-checkins at python.org
Wed Nov 12 08:08:51 CET 2008
Author: matthias.klose
Date: Wed Nov 12 08:08:51 2008
New Revision: 67198
Log:
- Issues #2588, #2589: Fix potential integer underflow and overflow
conditions in the PyOS_vsnprintf C API function. CVE-2008-3144.
Modified:
python/branches/release24-maint/Misc/NEWS
python/branches/release24-maint/Python/mysnprintf.c
Modified: python/branches/release24-maint/Misc/NEWS
==============================================================================
--- python/branches/release24-maint/Misc/NEWS (original)
+++ python/branches/release24-maint/Misc/NEWS Wed Nov 12 08:08:51 2008
@@ -27,6 +27,9 @@
- Issue #2586: Fix CVE-2008-1721, zlib crash from
zlib.decompressobj().flush(val) when val is not positive.
+- Issues #2588, #2589: Fix potential integer underflow and overflow
+ conditions in the PyOS_vsnprintf C API function. CVE-2008-3144.
+
Extension Modules
-----------------
Modified: python/branches/release24-maint/Python/mysnprintf.c
==============================================================================
--- python/branches/release24-maint/Python/mysnprintf.c (original)
+++ python/branches/release24-maint/Python/mysnprintf.c Wed Nov 12 08:08:51 2008
@@ -54,18 +54,28 @@
PyOS_vsnprintf(char *str, size_t size, const char *format, va_list va)
{
int len; /* # bytes written, excluding \0 */
-#ifndef HAVE_SNPRINTF
+#ifdef HAVE_SNPRINTF
+#define _PyOS_vsnprintf_EXTRA_SPACE 1
+#else
+#define _PyOS_vsnprintf_EXTRA_SPACE 512
char *buffer;
#endif
assert(str != NULL);
assert(size > 0);
assert(format != NULL);
+ /* We take a size_t as input but return an int. Sanity check
+ * our input so that it won't cause an overflow in the
+ * vsnprintf return value or the buffer malloc size. */
+ if (size > INT_MAX - _PyOS_vsnprintf_EXTRA_SPACE) {
+ len = -666;
+ goto Done;
+ }
#ifdef HAVE_SNPRINTF
len = vsnprintf(str, size, format, va);
#else
/* Emulate it. */
- buffer = PyMem_MALLOC(size + 512);
+ buffer = PyMem_MALLOC(size + _PyOS_vsnprintf_EXTRA_SPACE);
if (buffer == NULL) {
len = -666;
goto Done;
@@ -75,7 +85,7 @@
if (len < 0)
/* ignore the error */;
- else if ((size_t)len >= size + 512)
+ else if ((size_t)len >= size + _PyOS_vsnprintf_EXTRA_SPACE)
Py_FatalError("Buffer overflow in PyOS_snprintf/PyOS_vsnprintf");
else {
@@ -86,8 +96,10 @@
str[to_copy] = '\0';
}
PyMem_FREE(buffer);
-Done:
#endif
- str[size-1] = '\0';
+Done:
+ if (size > 0)
+ str[size-1] = '\0';
return len;
+#undef _PyOS_vsnprintf_EXTRA_SPACE
}
More information about the Python-checkins
mailing list