Re: [PATCH V5 01/13] namespaces: assign each namespace instance a serial number

["Serge E. Hallyn" <serge-A9i7LUbDfNHQT0dZR+AlfA@public.gmane.org>]

Quoting Richard Guy Briggs (rgb-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org):
> 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>

Acked-by: Serge Hallyn <serge.hallyn-Z7WLFzj8eWMS+FvcfC7Uqw@public.gmane.org>

> ---
>  fs/mount.h                     |    1 +
>  fs/namespace.c                 |    1 +
>  include/linux/ipc_namespace.h  |    1 +
>  include/linux/nsproxy.h        |   10 ++++++++++
>  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               |   18 ++++++++++++++++++
>  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, 54 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..9d627b5 100644
> --- a/include/linux/nsproxy.h
> +++ b/include/linux/nsproxy.h
> @@ -66,6 +66,16 @@ 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,
> +	__NS_MAX_INIT_SN= 5,
> +};
> +#define NS_DYN_INIT_SN	(__NS_MAX_INIT_SN - 1)
> +
>  int copy_namespaces(unsigned long flags, struct task_struct *tsk);
>  void exit_task_namespaces(struct task_struct *tsk);
>  void switch_task_namespaces(struct task_struct *tsk, struct nsproxy *new);
> diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h
> index 7246ef3..4d8023e 100644
> --- a/include/linux/pid_namespace.h
> +++ b/include/linux/pid_namespace.h
> @@ -43,6 +43,7 @@ struct pid_namespace {
>  	int hide_pid;
>  	int reboot;	/* group exit code if this pidns was rebooted */
>  	unsigned int proc_inum;
> +	long long	serial_num;
>  };
>  
>  extern struct pid_namespace init_pid_ns;
> diff --git a/include/linux/user_namespace.h b/include/linux/user_namespace.h
> index 4836ba3..159ac26 100644
> --- a/include/linux/user_namespace.h
> +++ b/include/linux/user_namespace.h
> @@ -27,6 +27,7 @@ struct user_namespace {
>  	kuid_t			owner;
>  	kgid_t			group;
>  	unsigned int		proc_inum;
> +	long long	serial_num;
>  
>  	/* Register of per-UID persistent keyrings for this namespace */
>  #ifdef CONFIG_PERSISTENT_KEYRINGS
> diff --git a/include/linux/utsname.h b/include/linux/utsname.h
> index 239e277..8490197 100644
> --- a/include/linux/utsname.h
> +++ b/include/linux/utsname.h
> @@ -24,6 +24,7 @@ struct uts_namespace {
>  	struct new_utsname name;
>  	struct user_namespace *user_ns;
>  	unsigned int proc_inum;
> +	long long	serial_num;
>  };
>  extern struct uts_namespace init_uts_ns;
>  
> diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
> index 361d260..5238a06 100644
> --- a/include/net/net_namespace.h
> +++ b/include/net/net_namespace.h
> @@ -61,6 +61,7 @@ struct net {
>  	struct user_namespace   *user_ns;	/* Owning user namespace */
>  
>  	unsigned int		proc_inum;
> +	long long	serial_num;
>  
>  	struct proc_dir_entry 	*proc_net;
>  	struct proc_dir_entry 	*proc_net_stat;
> diff --git a/init/version.c b/init/version.c
> index 1a4718e..cfdcb85 100644
> --- a/init/version.c
> +++ b/init/version.c
> @@ -36,6 +36,7 @@ struct uts_namespace init_uts_ns = {
>  	},
>  	.user_ns = &init_user_ns,
>  	.proc_inum = PROC_UTS_INIT_INO,
> +	.serial_num = NS_UTS_INIT_SN /* ns_serial() */,
>  };
>  EXPORT_SYMBOL_GPL(init_uts_ns);
>  
> diff --git a/ipc/msgutil.c b/ipc/msgutil.c
> index 7e70959..9aa66ae 100644
> --- a/ipc/msgutil.c
> +++ b/ipc/msgutil.c
> @@ -32,6 +32,7 @@ struct ipc_namespace init_ipc_ns = {
>  	.count		= ATOMIC_INIT(1),
>  	.user_ns = &init_user_ns,
>  	.proc_inum = PROC_IPC_INIT_INO,
> +	.serial_num = NS_IPC_INIT_SN /* ns_serial() */,
>  };
>  
>  atomic_t nr_ipc_ns = ATOMIC_INIT(1);
> diff --git a/ipc/namespace.c b/ipc/namespace.c
> index 59451c1..76dac5c 100644
> --- a/ipc/namespace.c
> +++ b/ipc/namespace.c
> @@ -41,6 +41,8 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
>  	}
>  	atomic_inc(&nr_ipc_ns);
>  
> +	ns->serial_num = ns_serial();
> +
>  	sem_init_ns(ns);
>  	msg_init_ns(ns);
>  	shm_init_ns(ns);
> diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c
> index 8e78110..0c2f25e 100644
> --- a/kernel/nsproxy.c
> +++ b/kernel/nsproxy.c
> @@ -41,6 +41,24 @@ struct nsproxy init_nsproxy = {
>  #endif
>  };
>  
> +/**
> + * 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)
> +{
> +	/* reserved for IPC, UTS, user, PID */
> +	static atomic64_t serial = ATOMIC_INIT(NS_DYN_INIT_SN);
> +	long long ret;
> +
> +	ret = atomic64_add_return(1, &serial);
> +	BUG_ON(!ret);
> +
> +	return ret;
> +}
> +
>  static inline struct nsproxy *create_nsproxy(void)
>  {
>  	struct nsproxy *nsproxy;
> diff --git a/kernel/pid.c b/kernel/pid.c
> index 9b9a266..3bf7127 100644
> --- a/kernel/pid.c
> +++ b/kernel/pid.c
> @@ -80,6 +80,7 @@ struct pid_namespace init_pid_ns = {
>  	.child_reaper = &init_task,
>  	.user_ns = &init_user_ns,
>  	.proc_inum = PROC_PID_INIT_INO,
> +	.serial_num = NS_PID_INIT_SN /* ns_serial() */,
>  };
>  EXPORT_SYMBOL_GPL(init_pid_ns);
>  
> diff --git a/kernel/pid_namespace.c b/kernel/pid_namespace.c
> index db95d8e..40a8b36 100644
> --- a/kernel/pid_namespace.c
> +++ b/kernel/pid_namespace.c
> @@ -109,6 +109,8 @@ static struct pid_namespace *create_pid_namespace(struct user_namespace *user_ns
>  	if (err)
>  		goto out_free_map;
>  
> +	ns->serial_num = ns_serial();
> +
>  	kref_init(&ns->kref);
>  	ns->level = level;
>  	ns->parent = get_pid_ns(parent_pid_ns);
> diff --git a/kernel/user.c b/kernel/user.c
> index 4efa393..2f597e0 100644
> --- a/kernel/user.c
> +++ b/kernel/user.c
> @@ -51,6 +51,7 @@ struct user_namespace init_user_ns = {
>  	.owner = GLOBAL_ROOT_UID,
>  	.group = GLOBAL_ROOT_GID,
>  	.proc_inum = PROC_USER_INIT_INO,
> +	.serial_num = NS_USER_INIT_SN /* ns_serial() */,
>  #ifdef CONFIG_PERSISTENT_KEYRINGS
>  	.persistent_keyring_register_sem =
>  	__RWSEM_INITIALIZER(init_user_ns.persistent_keyring_register_sem),
> diff --git a/kernel/user_namespace.c b/kernel/user_namespace.c
> index fcc0256..5c5c399 100644
> --- a/kernel/user_namespace.c
> +++ b/kernel/user_namespace.c
> @@ -92,6 +92,8 @@ int create_user_ns(struct cred *new)
>  		return ret;
>  	}
>  
> +	ns->serial_num = ns_serial();
> +
>  	atomic_set(&ns->count, 1);
>  	/* Leave the new->user_ns reference with the new user namespace. */
>  	ns->parent = parent_ns;
> diff --git a/kernel/utsname.c b/kernel/utsname.c
> index fd39312..d0cf7b5 100644
> --- a/kernel/utsname.c
> +++ b/kernel/utsname.c
> @@ -48,6 +48,8 @@ static struct uts_namespace *clone_uts_ns(struct user_namespace *user_ns,
>  		return ERR_PTR(err);
>  	}
>  
> +	ns->serial_num = ns_serial();
> +
>  	down_read(&uts_sem);
>  	memcpy(&ns->name, &old_ns->name, sizeof(ns->name));
>  	ns->user_ns = get_user_ns(user_ns);
> diff --git a/net/core/net_namespace.c b/net/core/net_namespace.c
> index 85b6269..3b5cfdb 100644
> --- a/net/core/net_namespace.c
> +++ b/net/core/net_namespace.c
> @@ -384,7 +384,13 @@ EXPORT_SYMBOL_GPL(get_net_ns_by_pid);
>  
>  static __net_init int net_ns_net_init(struct net *net)
>  {
> -	return proc_alloc_inum(&net->proc_inum);
> +	int ret;
> +
> +	ret = proc_alloc_inum(&net->proc_inum);
> +	if (ret)
> +		return ret;
> +	net->serial_num = ns_serial();
> +	return 0;
>  }
>  
>  static __net_exit void net_ns_net_exit(struct net *net)
> -- 
> 1.7.1