Re: [PATCH V4 1/8] namespaces: assign each namespace instance a serial number

Andy Lutomirski
2014-08-21T21:22:31Z

On Aug 20, 2014 8:12 PM, "Richard Guy Briggs" <rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> wrote:
>
> Generate and assign a serial number per namespace instance since boot.
>
> Use a serial number per namespace (unique across one boot of one kernel)
> instead of the inode number (which is claimed to have had the right to change
> reserved and is not necessarily unique if there is more than one proc fs) to
> uniquely identify it per kernel boot.
>
> Signed-off-by: Richard Guy Briggs <rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
> ---
> fs/mount.h | 1 +
> fs/namespace.c | 1 +
> include/linux/ipc_namespace.h | 1 +
> include/linux/nsproxy.h | 8 ++++++++
> include/linux/pid_namespace.h | 1 +
> include/linux/user_namespace.h | 1 +
> include/linux/utsname.h | 1 +
> include/net/net_namespace.h | 1 +
> init/version.c | 1 +
> ipc/msgutil.c | 1 +
> ipc/namespace.c | 2 ++
> kernel/nsproxy.c | 17 +++++++++++++++++
> kernel/pid.c | 1 +
> kernel/pid_namespace.c | 2 ++
> kernel/user.c | 1 +
> kernel/user_namespace.c | 2 ++
> kernel/utsname.c | 2 ++
> net/core/net_namespace.c | 8 +++++++-
> 18 files changed, 51 insertions(+), 1 deletions(-)
>
> diff --git a/fs/mount.h b/fs/mount.h
> index d55297f..c076f99 100644
> --- a/fs/mount.h
> +++ b/fs/mount.h
> @@ -5,6 +5,7 @@
> struct mnt_namespace {
> atomic_t count;
> unsigned int proc_inum;
> + long long serial_num;
> struct mount * root;
> struct list_head list;
> struct user_namespace *user_ns;
> diff --git a/fs/namespace.c b/fs/namespace.c
> index 182bc41..9af49ff 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2486,6 +2486,7 @@ static struct mnt_namespace *alloc_mnt_ns(struct user_namespace *user_ns)
> kfree(new_ns);
> return ERR_PTR(ret);
> }
> + new_ns->serial_num = ns_serial();
> new_ns->seq = atomic64_add_return(1, &mnt_ns_seq);
> atomic_set(&new_ns->count, 1);
> new_ns->root = NULL;
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index 35e7eca..8ccfb2d 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -69,6 +69,7 @@ struct ipc_namespace {
> struct user_namespace *user_ns;
>
> unsigned int proc_inum;
> + long long serial_num;
> };
>
> extern struct ipc_namespace init_ipc_ns;
> diff --git a/include/linux/nsproxy.h b/include/linux/nsproxy.h
> index b4ec59d..8e5fe0d 100644
> --- a/include/linux/nsproxy.h
> +++ b/include/linux/nsproxy.h
> @@ -66,6 +66,14 @@ static inline struct nsproxy *task_nsproxy(struct task_struct *tsk)
> return rcu_dereference(tsk->nsproxy);
> }
>
> +long long ns_serial(void);
> +enum {
> + NS_IPC_INIT_SN = 1,
> + NS_UTS_INIT_SN = 2,
> + NS_USER_INIT_SN = 3,
> + NS_PID_INIT_SN = 4,

Please add an extra value here for the first dynamic value...
> +/**
> + * ns_serial - compute a serial number for the namespace
> + *
> + * Compute a serial number for the namespace to uniquely identify it in
> + * audit records.
> + */
> +long long ns_serial(void)
> +{
> + static atomic64_t serial = ATOMIC_INIT(4); /* reserved for IPC, UTS, user, PID */

...and use it here.

Also, does this work on all architectures?

--Andy