Re: [PATCH 2.6.23-rc1] eCryptfs: fix lookup error for special files

[Michael Halcrow <mhalcrow@us.ibm.com>]

On Wed, Aug 01, 2007 at 10:01:14PM +0900, Ryusuke Konishi wrote:
> When ecryptfs_lookup() is called against special files, eCryptfs
> generates the following errors because it tries to treat them like
> regular eCryptfs files.
> 
> Error opening lower file for lower_dentry [0xffff810233a6f150], lower_mnt [0xffff810235bb4c80], and flags 
> [0x8000]
> Error opening lower_file to read header region
> Error attempting to read the [user.ecryptfs] xattr from the lower file; return value = [-95]
> Valid metadata not found in header region or xattr region; treating file as unencrypted
> 
> For instance, the problem can be reproduced by the steps below.
> 
>   # mkdir /root/crypt /mnt/crypt
>   # mount -t ecryptfs /root/crypt /mnt/crypt
>   # mknod /mnt/crypt/c0 c 0 0
>   # umount /mnt/crypt
>   # mount -t ecryptfs /root/crypt /mnt/crypt
>   # ls -l /mnt/crypt
> 
> This patch fixes it by adding a check similar to directories and
> symlinks.
> 
> Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>

> ---
>  fs/ecryptfs/inode.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
> 
> diff --git a/fs/ecryptfs/inode.c b/fs/ecryptfs/inode.c
> index 0a50942..131954b 100644
> --- a/fs/ecryptfs/inode.c
> +++ b/fs/ecryptfs/inode.c
> @@ -353,6 +353,10 @@ static struct dentry *ecryptfs_lookup(struct inode *dir, struct dentry *dentry,
>  		ecryptfs_printk(KERN_DEBUG, "Is a symlink; returning\n");
>  		goto out;
>  	}
> +	if (special_file(lower_inode->i_mode)) {
> +		ecryptfs_printk(KERN_DEBUG, "Is a special file; returning\n");
> +		goto out;
> +	}
>  	if (!nd) {
>  		ecryptfs_printk(KERN_DEBUG, "We have a NULL nd, just leave"
>  				"as we *think* we are about to unlink\n");