Re: [REVIEW][PATCH 6/6] fs: Allow CAP_SYS_ADMIN in s_user_ns to freeze and thaw filesystems

Christian Brauner
2018-05-24T15:59:50Z

On Wed, May 23, 2018 at 06:25:38PM -0500, Eric W. Biederman wrote:
> From: Seth Forshee <seth.forshee@canonical.com>
>
> The user in control of a super block should be allowed to freeze
> and thaw it. Relax the restrictions on the FIFREEZE and FITHAW
> ioctls to require CAP_SYS_ADMIN in s_user_ns.

Acked-by: Christian Brauner <christian@brauner.io>

>
> Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
> ---
> fs/ioctl.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/fs/ioctl.c b/fs/ioctl.c
> index 4823431d1c9d..b445b13fc59b 100644
> --- a/fs/ioctl.c
> +++ b/fs/ioctl.c
> @@ -549,7 +549,7 @@ static int ioctl_fsfreeze(struct file *filp)
> {
> struct super_block *sb = file_inode(filp)->i_sb;
>
> - if (!capable(CAP_SYS_ADMIN))
> + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
> return -EPERM;
>
> /* If filesystem doesn't support freeze feature, return. */
> @@ -566,7 +566,7 @@ static int ioctl_fsthaw(struct file *filp)
> {
> struct super_block *sb = file_inode(filp)->i_sb;
>
> - if (!capable(CAP_SYS_ADMIN))
> + if (!ns_capable(sb->s_user_ns, CAP_SYS_ADMIN))
> return -EPERM;
>
> /* Thaw */
> --
> 2.14.1
>