From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752616AbaLDAYg (ORCPT ); Wed, 3 Dec 2014 19:24:36 -0500 Received: from aserp1040.oracle.com ([141.146.126.69]:44565 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751905AbaLDAYf (ORCPT ); Wed, 3 Dec 2014 19:24:35 -0500 From: Sasha Levin To: linux-kernel@vger.kernel.org Cc: Sasha Levin , Hugh Dickins , linux-mm@kvack.org Subject: [PATCH] mm: shmem: avoid overflowing in shmem_fallocate Date: Wed, 3 Dec 2014 19:24:07 -0500 Message-Id: <1417652657-1801-1-git-send-email-sasha.levin@oracle.com> X-Mailer: git-send-email 2.1.0 X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org "offset + len" has the potential of overflowing. Validate this user input first to avoid undefined behaviour. Signed-off-by: Sasha Levin --- mm/shmem.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/mm/shmem.c b/mm/shmem.c index 185836b..5a0e344 100644 --- a/mm/shmem.c +++ b/mm/shmem.c @@ -2098,6 +2098,9 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset, } /* We need to check rlimit even when FALLOC_FL_KEEP_SIZE */ + error = -EOVERFLOW; + if ((u64)len + offset < (u64)len) + goto out; error = inode_newsize_ok(inode, offset + len); if (error) goto out; -- 1.7.10.4