linux-kernel - Re: [PATCH 4.4 095/105] udf: Detect incorrect directory size

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Date:   Fri, 20 Jul 2018 20:19:19 +0100
From:   Ben Hutchings <ben.hutchings@...ethink.co.uk>
To:     Anatoly Trosinenko <anatoly.trosinenko@...il.com>,
        Jan Kara <jack@...e.cz>
Cc:     stable@...r.kernel.org,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4.4 095/105] udf: Detect incorrect directory size

On Sun, 2018-07-01 at 18:02 +0200, Greg Kroah-Hartman wrote:
> 4.4-stable review patch.  If anyone has any objections, please let me know.
> 
> ------------------
> 
> From: Jan Kara <jack@...e.cz>
> 
> commit fa65653e575fbd958bdf5fb9c4a71a324e39510d upstream.
> 
> Detect when a directory entry is (possibly partially) beyond directory
> size and return EIO in that case since it means the filesystem is
> corrupted. Otherwise directory operations can further corrupt the
> directory and possibly also oops the kernel.
[...]
> --- a/fs/udf/directory.c
> +++ b/fs/udf/directory.c
> @@ -150,6 +150,9 @@ struct fileIdentDesc *udf_fileident_read
>  			       sizeof(struct fileIdentDesc));
>  		}
>  	}
> +	/* Got last entry outside of dir size - fs is corrupted! */
> +	if (*nf_pos > dir->i_size)
> +		return NULL;
>  	return fi;
>  }
>  

Is the same check needed when iinfo->i_alloc_type ==
ICBTAG_FLAG_AD_IN_ICB?

Ben.

-- 
Ben Hutchings, Software Developer                         Codethink Ltd
https://www.codethink.co.uk/                 Dale House, 35 Dale Street
                                     Manchester, M1 2HF, United Kingdom