linux-kernel - Re: [PATCH] erofs: move erofs out of staging

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Message-ID: <1405781266.69008.1566116210649.JavaMail.zimbra@nod.at>
Date:   Sun, 18 Aug 2019 10:16:50 +0200 (CEST)
From:   Richard Weinberger <richard@....at>
To:     Gao Xiang <hsiangkao@....com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        devel <devel@...verdev.osuosl.org>,
        linux-erofs <linux-erofs@...ts.ozlabs.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Stephen Rothwell <sfr@...b.auug.org.au>, tytso <tytso@....edu>,
        Pavel Machek <pavel@...x.de>, David Sterba <dsterba@...e.cz>,
        Amir Goldstein <amir73il@...il.com>,
        Christoph Hellwig <hch@...radead.org>,
        Darrick <darrick.wong@...cle.com>,
        Dave Chinner <david@...morbit.com>,
        Jaegeuk Kim <jaegeuk@...nel.org>, Jan Kara <jack@...e.cz>,
        torvalds <torvalds@...ux-foundation.org>,
        Chao Yu <yuchao0@...wei.com>, Miao Xie <miaoxie@...wei.com>,
        Li Guifu <bluce.liguifu@...wei.com>,
        Fang Wei <fangwei1@...wei.com>,
        Gao Xiang <gaoxiang25@...wei.com>
Subject: Re: [PATCH] erofs: move erofs out of staging

----- Ursprüngliche Mail -----
>> While digging a little into the code I noticed that you have very few
>> checks of the on-disk data.
>> For example ->u.i_blkaddr. I gave it a try and created a
>> malformed filesystem where u.i_blkaddr is 0xdeadbeef, it causes the kernel
>> to loop forever around erofs_read_raw_page().
> 
> I don't fuzz all the on-disk fields for EROFS, I will do later..
> You can see many in-kernel filesystems are still hardening the related
> stuff. Anyway, I will dig into this field you mentioned recently, but
> I think it can be fixed easily later.

This is no excuse to redo all these bugs. :-)

I know that many in-kernel filesystems trust the disk ultimately, this is a
problem and huge attack vector.

Thanks,
//richard