From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751804Ab0LMGLo (ORCPT ); Mon, 13 Dec 2010 01:11:44 -0500 Received: from e28smtp06.in.ibm.com ([122.248.162.6]:51699 "EHLO e28smtp06.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751235Ab0LMGLn (ORCPT ); Mon, 13 Dec 2010 01:11:43 -0500 From: Harsh Prateek Bora To: linux-kernel@vger.kernel.org Cc: kamezawa.hiroyu@jp.fujitsu.com, aneesh.kumar@linux.vnet.ibm.com, Harsh Prateek Bora Subject: [PATCH v2] Typecasting required for comparing unlike datatypes Date: Mon, 13 Dec 2010 11:41:35 +0530 Message-Id: <1292220695-6578-1-git-send-email-harsh@linux.vnet.ibm.com> X-Mailer: git-send-email 1.7.1.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The existing code causes the if condition to pass when it should fail on a *64-bit kernel* because of implicit data type conversions. It can be observed by passing pos = -1 and count = some positive number. This results in function returning EOVERFLOW instead of EINVAL. With this patch, the function returns EINVAL when pos is -1 and count is a positive number. This can be tested by calling sendfile with offset = -1 and count = some positive number on a 64-bit kernel. Signed-off-by: Harsh Prateek Bora Acked-by: KAMEZAWA Hiroyuki --- fs/read_write.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 431a0ed..a8eabd4 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -38,7 +38,7 @@ __negative_fpos_check(struct file *file, loff_t pos, size_t count) * pos or pos+count is negative here, check overflow. * too big "count" will be caught in rw_verify_area(). */ - if ((pos < 0) && (pos + count < pos)) + if ((pos < 0) && ( (loff_t) (pos + count) < pos)) return -EOVERFLOW; if (file->f_mode & FMODE_UNSIGNED_OFFSET) return 0; -- 1.7.1.1