Re: [PATCH] eCryptfs: Regression in unencrypted filename symlinks

[Dave Kleikamp <shaggy@linux.vnet.ibm.com>]

On Fri, 2009-02-06 at 18:06 -0600, Tyler Hicks wrote:
> The addition of filename encryption caused a regression in unencrypted
> filename symlink support.  ecryptfs_copy_filename() is used when dealing
> with unencrypted filenames and it reported that the new, copied filename
> was a character longer than it should have been.
> 
> This caused the return value of readlink() to count the NULL byte of the
> symlink target.  Most applications don't care about the extra NULL byte,
> but a version control system (bzr) helped in discovering the bug.
> 
> Signed-off-by: Tyler Hicks <tyhicks@linux.vnet.ibm.com>

Acked-by: Dave Kleikamp <shaggy@linux.vnet.ibm.com>

> ---
>  fs/ecryptfs/crypto.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/ecryptfs/crypto.c b/fs/ecryptfs/crypto.c
> index c01e043..f6caeb1 100644
> --- a/fs/ecryptfs/crypto.c
> +++ b/fs/ecryptfs/crypto.c
> @@ -1716,7 +1716,7 @@ static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
>  {
>  	int rc = 0;
> 
> -	(*copied_name) = kmalloc((name_size + 2), GFP_KERNEL);
> +	(*copied_name) = kmalloc((name_size + 1), GFP_KERNEL);
>  	if (!(*copied_name)) {
>  		rc = -ENOMEM;
>  		goto out;
> @@ -1726,7 +1726,7 @@ static int ecryptfs_copy_filename(char **copied_name, size_t *copied_name_size,
>  						 * in printing out the
>  						 * string in debug
>  						 * messages */
> -	(*copied_name_size) = (name_size + 1);
> +	(*copied_name_size) = name_size;
>  out:
>  	return rc;
>  }
-- 
David Kleikamp
IBM Linux Technology Center