linux-kernel - Re: [PATCH, v2] ufs: ensure link targets are NUL-terminated

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Message-ID: <20081214211246.GA7743@rain>
Date:	Mon, 15 Dec 2008 00:12:47 +0300
From:	Evgeniy Dushistov <dushistov@...l.ru>
To:	Duane Griffin <duaneg@...da.com>
Cc:	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	Boaz Harrosh <bharrosh@...asas.com>
Subject: Re: [PATCH, v2] ufs: ensure link targets are NUL-terminated

On Thu, Dec 11, 2008 at 10:36:08PM +0000, Duane Griffin wrote:
> Ensure link targets are NUL-terminated, even if corrupted on-disk.
> 
> Signed-off-by: Duane Griffin <duaneg@...da.com>
> ---
> 
> V2: terminate when the link is read instead of every time it is
> followed, as suggested by Dave Kleikamp.
> 
> diff --git a/fs/ufs/inode.c b/fs/ufs/inode.c
> index 39f8778..a22f64d 100644
> --- a/fs/ufs/inode.c
> +++ b/fs/ufs/inode.c
> @@ -606,9 +606,11 @@ static void ufs_set_inode_ops(struct inode *inode)
>  		inode->i_fop = &ufs_dir_operations;
>  		inode->i_mapping->a_ops = &ufs_aops;
>  	} else if (S_ISLNK(inode->i_mode)) {
> -		if (!inode->i_blocks)
> +		if (!inode->i_blocks) {
> +			char *link = UFS_I(inode)->i_u1.i_symlink;
>  			inode->i_op = &ufs_fast_symlink_inode_operations;
> -		else {
> +			link[inode->i_size] = '\0';
> +		} else {
>  			inode->i_op = &page_symlink_inode_operations;
>  			inode->i_mapping->a_ops = &ufs_aops;
>  		}

if we talk about corrupted file system, may be also ensure
that inode->i_size <= sizeof(i_u1)-1 before write '\0' to it.

-- 
/Evgeniy

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