Re: [PATCH 1/2] fs: require inode_owner_or_capable for F_SET_RW_HINT

[Christian Brauner <brauner@xxxxxxxxxx>]

On Fri, Nov 22, 2024 at 01:29:24PM +0100, Christoph Hellwig wrote:
> F_SET_RW_HINT controls data placement in the file system and / or
> device and should not be available to everyone who can read a given file.
> 
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>  fs/fcntl.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/fs/fcntl.c b/fs/fcntl.c
> index 22dd9dcce7ec..7fc6190da342 100644
> --- a/fs/fcntl.c
> +++ b/fs/fcntl.c
> @@ -375,6 +375,9 @@ static long fcntl_set_rw_hint(struct file *file, unsigned int cmd,
>  	u64 __user *argp = (u64 __user *)arg;
>  	u64 hint;
>  
> +	if (!inode_owner_or_capable(file_mnt_idmap(file), inode))
> +		return -EPERM;
> +

Bah, nice catch.