Re: [PATCH] fsnotify: compile out fsnotify permission hooks if !FANOTIFY_ACCESS_PERMISSIONS

[Jan Kara <jack@suse.cz>]

On Tue 09-01-24 20:22:45, Amir Goldstein wrote:
> The depency of FANOTIFY_ACCESS_PERMISSIONS on SECURITY made sure that
> the fsnotify permission hooks were never called when SECURITY was
> disabled.
> 
> Moving the fsnotify permission hook out of the secutiy hook broke that
> optimisation.
> 
> Reported-and-tested-by: Jens Axboe <axboe@kernel.dk>
> Closes: https://lore.kernel.org/linux-fsdevel/53682ece-f0e7-48de-9a1c-879ee34b0449@kernel.dk/
> Fixes: d9e5d31084b0 ("fsnotify: optionally pass access range in file permission hooks")
> Signed-off-by: Amir Goldstein <amir73il@gmail.com>

Originally I didn't notice this was directed to Christian but it makes
sense since he merged the original patches. The fix looks good (modulo the
typo fixes from Jens). Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

								Honza

> ---
>  include/linux/fsnotify.h | 19 +++++++++++++++++++
>  1 file changed, 19 insertions(+)
> 
> diff --git a/include/linux/fsnotify.h b/include/linux/fsnotify.h
> index 11e6434b8e71..8300a5286988 100644
> --- a/include/linux/fsnotify.h
> +++ b/include/linux/fsnotify.h
> @@ -100,6 +100,7 @@ static inline int fsnotify_file(struct file *file, __u32 mask)
>  	return fsnotify_parent(path->dentry, mask, path, FSNOTIFY_EVENT_PATH);
>  }
>  
> +#ifdef CONFIG_FANOTIFY_ACCESS_PERMISSIONS
>  /*
>   * fsnotify_file_area_perm - permission hook before access to file range
>   */
> @@ -145,6 +146,24 @@ static inline int fsnotify_open_perm(struct file *file)
>  	return fsnotify_file(file, FS_OPEN_PERM);
>  }
>  
> +#else
> +static inline int fsnotify_file_area_perm(struct file *file, int perm_mask,
> +					  const loff_t *ppos, size_t count)
> +{
> +	return 0;
> +}
> +
> +static inline int fsnotify_file_perm(struct file *file, int perm_mask)
> +{
> +	return 0;
> +}
> +
> +static inline int fsnotify_open_perm(struct file *file)
> +{
> +	return 0;
> +}
> +#endif
> +
>  /*
>   * fsnotify_link_count - inode's link count changed
>   */
> -- 
> 2.34.1
> 
-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR