linux-ext4 - Re: [PATCH] ext4: Prevent creation of files larger than RLIMIT

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Message-ID: <20100504062815.GA8091@amitarora.in.ibm.com>
Date:	Tue, 4 May 2010 11:58:16 +0530
From:	"Amit K. Arora" <aarora@...ux.vnet.ibm.com>
To:	Nikanth Karthikesan <knikanth@...e.de>
Cc:	"Theodore Ts'o" <tytso@....edu>, Andreas Dilger <adilger@....com>,
	linux-ext4@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>, coly.li@...e.de,
	Nick Piggin <npiggin@...e.de>,
	Alexander Viro <viro@...iv.linux.org.uk>,
	linux-fsdevel@...r.kernel.org,
	Eelis <opensuse.org@...tacts.eelis.net>,
	Amit Arora <aarora@...ibm.com>,
	Christoph Hellwig <hch@...radead.org>
Subject: Re: [PATCH] ext4: Prevent creation of files larger than
	RLIMIT_FSIZE using fallocate

On Tue, May 04, 2010 at 11:15:04AM +0530, Nikanth Karthikesan wrote:
> I assumed that Amit would send a patch with s-o-b, if not, please take
> this patch.
Have added my sign-off below. Thanks!

--
Regards,
Amit Arora
> Thanks
> Nikanth
> 
> Prevent creation of files larger than RLIMIT_FSIZE using fallocate.
> 
> Currently using posix_fallocate one can bypass an RLIMIT_FSIZE limit
> and create a file larger than the limit. Add a check for that.
> 
> 
> Signed-off-by: Nikanth Karthikesan <knikanth@...e.de>
Signed-off-by: Amit Arora <aarora@...ibm.com>
 
> ---
> 
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 236b834..39b8123 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3672,6 +3672,11 @@ long ext4_fallocate(struct inode *inode, int mode, loff_t offset, loff_t len)
>  	 */
>  	credits = ext4_chunk_trans_blocks(inode, max_blocks);
>  	mutex_lock(&inode->i_mutex);
> +	ret = inode_newsize_ok(inode, (len + offset));
> +	if (ret) {
> +		mutex_unlock(&inode->i_mutex);
> +		return ret;
> +	}
>  retry:
>  	while (ret >= 0 && ret < max_blocks) {
>  		block = block + ret;
--
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