On 2025-09-10, Christian Brauner <brauner@kernel.org> wrote:
> Add a helper to easily check whether a given namespace is the caller's
> current namespace. This is currently open-coded in a lot of places.
> Simply switch on the type and compare the results.
>
> Signed-off-by: Christian Brauner <brauner@kernel.org>
Looks good, feel free to add my
Reviewed-by: Aleksa Sarai <cyphar@cyphar.com>
> ---
> include/linux/nsfs.h | 16 +++++++++++++++-
> 1 file changed, 15 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/nsfs.h b/include/linux/nsfs.h
> index fb84aa538091..e5a5fa83d36b 100644
> --- a/include/linux/nsfs.h
> +++ b/include/linux/nsfs.h
> @@ -5,6 +5,8 @@
> #define _LINUX_NSFS_H
>
> #include <linux/ns_common.h>
> +#include <linux/cred.h>
> +#include <linux/pid_namespace.h>
>
> struct path;
> struct task_struct;
> @@ -22,5 +24,17 @@ int ns_get_name(char *buf, size_t size, struct task_struct *task,
> const struct proc_ns_operations *ns_ops);
> void nsfs_init(void);
>
> -#endif /* _LINUX_NSFS_H */
> +#define __current_namespace_from_type(__ns) \
> + _Generic((__ns), \
> + struct cgroup_namespace *: current->nsproxy->cgroup_ns, \
> + struct ipc_namespace *: current->nsproxy->ipc_ns, \
> + struct net *: current->nsproxy->net_ns, \
> + struct pid_namespace *: task_active_pid_ns(current), \
> + struct mnt_namespace *: current->nsproxy->mnt_ns, \
> + struct time_namespace *: current->nsproxy->time_ns, \
> + struct user_namespace *: current_user_ns(), \
> + struct uts_namespace *: current->nsproxy->uts_ns)
> +
> +#define current_in_namespace(__ns) (__current_namespace_from_type(__ns) == __ns)
>
> +#endif /* _LINUX_NSFS_H */
>
> --
> 2.47.3
>
--
Aleksa Sarai
Senior Software Engineer (Containers)
SUSE Linux GmbH
https://www.cyphar.com/