From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Subject: Re: [PATCH] ext4: fix wrong verification in ext4_ext_insert_index Date: Mon, 17 Oct 2011 16:49:32 +0800 Message-ID: <4E9BEC1C.3050905@tao.ma> References: <1318831867-8225-1-git-send-email-xiaoqiangnk@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: linux-ext4@vger.kernel.org, tytso@mit.edu To: Yongqiang Yang Return-path: Received: from oproxy7-pub.bluehost.com ([67.222.55.9]:56163 "HELO oproxy7-pub.bluehost.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752084Ab1JQItj (ORCPT ); Mon, 17 Oct 2011 04:49:39 -0400 In-Reply-To: <1318831867-8225-1-git-send-email-xiaoqiangnk@gmail.com> Sender: linux-ext4-owner@vger.kernel.org List-ID: Hi yongqiang, On 10/17/2011 02:11 PM, Yongqiang Yang wrote: > After inserting an new index, current number of indexes should > be greater than original number by 1. So if the new index is > less or equal than LAST_INDEX + 1, then indexes are continugous. > If new index will be placed on the end, then ix will equals > LAST_INDEX + 1. Index entries has been verifiyed in pervious code > in ext4_ext_insert_index. Thanks for the effort. But actually this is caused by my original patch 4fd30c033, and your fix doesn't resolve the problem I want to fix. So consider ix is already overflow, the check can't prevent it from stamping on the memory after this extent block. I have sent another fix for it. Thanks Tao > > Signed-off-by: Yongqiang Yang > --- > fs/ext4/extents.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 2dff31e..322398e 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -779,7 +779,7 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode, > ix = curp->p_idx; > } > > - if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr))) { > + if (unlikely(ix > EXT_LAST_INDEX(curp->p_hdr) + 1)) { > EXT4_ERROR_INODE(inode, "ix > EXT_LAST_INDEX!"); > return -EIO; > }