commit 71765770a4a8cb0bc66b8b015e99606e23526957
author Victor Stinner <victor.stinner@gmail.com> Mon Jun 24 23:13:24 2013 +0200
committer Victor Stinner <victor.stinner@gmail.com> Mon Jun 24 23:13:24 2013 +0200
tree 44594bd59febd271db13de25acbd61a13842cb9e
parent bc8ccce7298df728b2d81bd9c3bb9c8e236b882b

Issue #9566: _winapi.WriteFile() now truncates length to DWORD_MAX (4294967295)

Modules/_winapi.c

diff --git a/Modules/_winapi.c b/Modules/_winapi.c
index 1074891..c34d2db 100644
--- a/Modules/_winapi.c
+++ b/Modules/_winapi.c
@@ -62,6 +62,8 @@
 
 #define T_HANDLE T_POINTER
 
+#define DWORD_MAX 4294967295U
+
 /* Grab CancelIoEx dynamically from kernel32 */
 static int has_CancelIoEx = -1;
 static BOOL (CALLBACK *Py_CancelIoEx)(HANDLE, LPOVERLAPPED);
@@ -1142,7 +1144,7 @@
     HANDLE handle;
     Py_buffer _buf, *buf;
     PyObject *bufobj;
-    DWORD written;
+    DWORD len, written;
     BOOL ret;
     int use_overlapped = 0;
     DWORD err;
@@ -1170,7 +1172,8 @@
     }
 
     Py_BEGIN_ALLOW_THREADS
-    ret = WriteFile(handle, buf->buf, buf->len, &written,
+    len = (DWORD)Py_MIN(buf->len, DWORD_MAX);
+    ret = WriteFile(handle, buf->buf, len, &written,
                     overlapped ? &overlapped->overlapped : NULL);
     Py_END_ALLOW_THREADS