Re: [PATCH 05/19] userns: Replace in_userns with current_in_userns

["Serge E. Hallyn" <serge.hallyn@ubuntu.com>]

On Wed, Dec 02, 2015 at 09:40:05AM -0600, Seth Forshee wrote:
> All current callers of in_userns pass current_user_ns as the
> first argument. Simplify by replacing in_userns with
> current_in_userns which checks whether current_user_ns is in the
> namespace supplied as an argument.
> 
> Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
> Acked-by: James Morris <james.l.morris@oracle.com>

Acked-by: Serge Hallyn <serge.hallyn@canonical.com>

> ---
>  fs/namespace.c                 | 2 +-
>  include/linux/user_namespace.h | 6 ++----
>  kernel/user_namespace.c        | 6 +++---
>  security/commoncap.c           | 2 +-
>  4 files changed, 7 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 2101ce7b96ab..18fc58760aec 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -3286,7 +3286,7 @@ bool mnt_may_suid(struct vfsmount *mnt)
>  	 * in other namespaces.
>  	 */
>  	return !(mnt->mnt_flags & MNT_NOSUID) && check_mnt(real_mount(mnt)) &&
> -	       in_userns(current_user_ns(), mnt->mnt_sb->s_user_ns);
> +	       current_in_userns(mnt->mnt_sb->s_user_ns);
>  }
>  
>  static struct ns_common *mntns_get(struct task_struct *task)
> diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
> index a43faa727124..9217169c64cb 100644
> --- a/include/linux/user_namespace.h
> +++ b/include/linux/user_namespace.h
> @@ -72,8 +72,7 @@ extern ssize_t proc_projid_map_write(struct file *, const char __user *, size_t,
>  extern ssize_t proc_setgroups_write(struct file *, const char __user *, size_t, loff_t *);
>  extern int proc_setgroups_show(struct seq_file *m, void *v);
>  extern bool userns_may_setgroups(const struct user_namespace *ns);
> -extern bool in_userns(const struct user_namespace *ns,
> -		      const struct user_namespace *target_ns);
> +extern bool current_in_userns(const struct user_namespace *target_ns);
>  #else
>  
>  static inline struct user_namespace *get_user_ns(struct user_namespace *ns)
> @@ -103,8 +102,7 @@ static inline bool userns_may_setgroups(const struct user_namespace *ns)
>  	return true;
>  }
>  
> -static inline bool in_userns(const struct user_namespace *ns,
> -			     const struct user_namespace *target_ns)
> +static inline bool current_in_userns(const struct user_namespace *target_ns)
>  {
>  	return true;
>  }
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index 69fbc377357b..5960edc7e644 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -949,10 +949,10 @@ bool userns_may_setgroups(const struct user_namespace *ns)
>   * Returns true if @ns is the same namespace as or a descendant of
>   * @target_ns.
>   */
> -bool in_userns(const struct user_namespace *ns,
> -	       const struct user_namespace *target_ns)
> +bool current_in_userns(const struct user_namespace *target_ns)
>  {
> -	for (; ns; ns = ns->parent) {
> +	struct user_namespace *ns;
> +	for (ns = current_user_ns(); ns; ns = ns->parent) {
>  		if (ns == target_ns)
>  			return true;
>  	}
> diff --git a/security/commoncap.c b/security/commoncap.c
> index 6243aef5860e..2119421613f6 100644
> --- a/security/commoncap.c
> +++ b/security/commoncap.c
> @@ -450,7 +450,7 @@ static int get_file_caps(struct linux_binprm *bprm, bool *effective, bool *has_c
>  
>  	if (!mnt_may_suid(bprm->file->f_path.mnt))
>  		return 0;
> -	if (!in_userns(current_user_ns(), bprm->file->f_path.mnt->mnt_sb->s_user_ns))
> +	if (!current_in_userns(bprm->file->f_path.mnt->mnt_sb->s_user_ns))
>  		return 0;
>  
>  	rc = get_vfs_caps_from_disk(bprm->file->f_path.dentry, &vcaps);
> -- 
> 1.9.1