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Message-ID: <877g2ec7tg.fsf@x220.int.ebiederm.org>
Date: Tue, 12 Aug 2014 03:37:31 -0700
From: ebiederm@...ssion.com (Eric W. Biederman)
To: Manfred Spraul <manfred@...orfullife.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>,
LKML <linux-kernel@...r.kernel.org>,
Davidlohr Bueso <davidlohr.bueso@...com>,
Michael Kerrisk <mtk.manpages@...il.com>,
Rafael Aquini <aquini@...hat.com>,
Rik van Riel <riel@...hat.com>, 1vier1@....de,
serge@...lyn.com, containers@...ts.linux-foundation.org
Subject: Re: [PATCH 3/3] ipc namespace: copy settings from parent namespace
Manfred Spraul <manfred@...orfullife.com> writes:
Sigh. Patches for new code during the merge window. It is a really
rotten time to look at new things.
> Right now, each new IPC namespace starts with the kernel default values.
> This means that changes that were made to the limits get overwritten.
>
> With this patch, a new namespace inherits the settings from the parent
> namespace, which is less surprising.
In principle I agree.
In practice I have to ask what have you done to survey applications
that use the ipc namespace to see if they will break with this change in
semantics.
Eric
> The patch updates
> - SysV msg
> - SysV sem
> - SysV shm
> - POSIX mqueues
>
> Cc: serge@...lyn.com
> Cc: ebiederm@...ssion.com
> Cc: containers@...ts.linux-foundation.org
> Cc: mtk.manpages@...il.com
>
> Signed-off-by: Manfred Spraul <manfred@...orfullife.com>
> ---
> include/linux/ipc_namespace.h | 6 ++++--
> ipc/mqueue.c | 23 ++++++++++++++++-------
> ipc/msg.c | 16 +++++++++++-----
> ipc/namespace.c | 8 ++++----
> ipc/sem.c | 19 +++++++++++++------
> ipc/shm.c | 19 +++++++++++++------
> ipc/util.h | 20 ++++++++++++++------
> 7 files changed, 75 insertions(+), 36 deletions(-)
>
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index e365d5e..1cc36a0 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -73,7 +73,7 @@ static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
> #endif /* CONFIG_SYSVIPC */
>
> #ifdef CONFIG_POSIX_MQUEUE
> -extern int mq_init_ns(struct ipc_namespace *ns);
> +extern int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> /*
> * POSIX Message Queue default values:
> *
> @@ -108,7 +108,9 @@ extern int mq_init_ns(struct ipc_namespace *ns);
> #define DFLT_MSGSIZEMAX 8192
> #define HARD_MSGSIZEMAX (16*1024*1024)
> #else
> -static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
> +static inline int mq_init_ns(struct ipc_namespace *ns,
> + struct ipc_namespace *old_ns)
> +{ return 0; }
> #endif
>
> #if defined(CONFIG_IPC_NS)
> diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> index 4fcf39a..3473072d 100644
> --- a/ipc/mqueue.c
> +++ b/ipc/mqueue.c
> @@ -1397,14 +1397,23 @@ static struct file_system_type mqueue_fs_type = {
> .fs_flags = FS_USERNS_MOUNT,
> };
>
> -int mq_init_ns(struct ipc_namespace *ns)
> +int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> {
> + if (old_ns != NULL) {
> + ns->mq_queues_max = old_ns->mq_queues_max;
> + ns->mq_msg_max = old_ns->mq_msg_max;
> + ns->mq_msgsize_max = old_ns->mq_msgsize_max;
> + ns->mq_msg_default = old_ns->mq_msg_default;
> + ns->mq_msgsize_default = old_ns->mq_msgsize_default;
> + } else {
> + ns->mq_queues_max = DFLT_QUEUESMAX;
> + ns->mq_msg_max = DFLT_MSGMAX;
> + ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
> + ns->mq_msg_default = DFLT_MSG;
> + ns->mq_msgsize_default = DFLT_MSGSIZE;
> + }
> +
> ns->mq_queues_count = 0;
> - ns->mq_queues_max = DFLT_QUEUESMAX;
> - ns->mq_msg_max = DFLT_MSGMAX;
> - ns->mq_msgsize_max = DFLT_MSGSIZEMAX;
> - ns->mq_msg_default = DFLT_MSG;
> - ns->mq_msgsize_default = DFLT_MSGSIZE;
>
> ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns);
> if (IS_ERR(ns->mq_mnt)) {
> @@ -1444,7 +1453,7 @@ static int __init init_mqueue_fs(void)
>
> spin_lock_init(&mq_lock);
>
> - error = mq_init_ns(&init_ipc_ns);
> + error = mq_init_ns(&init_ipc_ns, NULL);
> if (error)
> goto out_filesystem;
>
> diff --git a/ipc/msg.c b/ipc/msg.c
> index a7261d5..3cbd2ad 100644
> --- a/ipc/msg.c
> +++ b/ipc/msg.c
> @@ -990,11 +990,17 @@ SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
> }
>
>
> -void msg_init_ns(struct ipc_namespace *ns)
> +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> {
> - ns->msg_ctlmax = MSGMAX;
> - ns->msg_ctlmnb = MSGMNB;
> - ns->msg_ctlmni = MSGMNI;
> + if (old_ns != NULL) {
> + ns->msg_ctlmax = old_ns->msg_ctlmax;
> + ns->msg_ctlmnb = old_ns->msg_ctlmnb;
> + ns->msg_ctlmni = old_ns->msg_ctlmni;
> + } else {
> + ns->msg_ctlmax = MSGMAX;
> + ns->msg_ctlmnb = MSGMNB;
> + ns->msg_ctlmni = MSGMNI;
> + }
>
> atomic_set(&ns->msg_bytes, 0);
> atomic_set(&ns->msg_hdrs, 0);
> @@ -1036,7 +1042,7 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
>
> void __init msg_init(void)
> {
> - msg_init_ns(&init_ipc_ns);
> + msg_init_ns(&init_ipc_ns, NULL);
>
> ipc_init_proc_interface("sysvipc/msg",
> " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
> diff --git a/ipc/namespace.c b/ipc/namespace.c
> index 1a3ffd4..97e3332 100644
> --- a/ipc/namespace.c
> +++ b/ipc/namespace.c
> @@ -33,7 +33,7 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
> }
>
> atomic_set(&ns->count, 1);
> - err = mq_init_ns(ns);
> + err = mq_init_ns(ns, old_ns);
> if (err) {
> proc_free_inum(ns->proc_inum);
> kfree(ns);
> @@ -41,9 +41,9 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
> }
> atomic_inc(&nr_ipc_ns);
>
> - sem_init_ns(ns);
> - msg_init_ns(ns);
> - shm_init_ns(ns);
> + sem_init_ns(ns, old_ns);
> + msg_init_ns(ns, old_ns);
> + shm_init_ns(ns, old_ns);
>
> ns->user_ns = get_user_ns(user_ns);
>
> diff --git a/ipc/sem.c b/ipc/sem.c
> index 454f6c6..f1ded77 100644
> --- a/ipc/sem.c
> +++ b/ipc/sem.c
> @@ -170,12 +170,19 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
> #define sc_semopm sem_ctls[2]
> #define sc_semmni sem_ctls[3]
>
> -void sem_init_ns(struct ipc_namespace *ns)
> +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> {
> - ns->sc_semmsl = SEMMSL;
> - ns->sc_semmns = SEMMNS;
> - ns->sc_semopm = SEMOPM;
> - ns->sc_semmni = SEMMNI;
> + if (old_ns != NULL) {
> + ns->sc_semmsl = old_ns->sc_semmsl;
> + ns->sc_semmns = old_ns->sc_semmns;
> + ns->sc_semopm = old_ns->sc_semopm;
> + ns->sc_semmni = old_ns->sc_semmni;
> + } else {
> + ns->sc_semmsl = SEMMSL;
> + ns->sc_semmns = SEMMNS;
> + ns->sc_semopm = SEMOPM;
> + ns->sc_semmni = SEMMNI;
> + }
> ns->used_sems = 0;
> ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
> }
> @@ -190,7 +197,7 @@ void sem_exit_ns(struct ipc_namespace *ns)
>
> void __init sem_init(void)
> {
> - sem_init_ns(&init_ipc_ns);
> + sem_init_ns(&init_ipc_ns, NULL);
> ipc_init_proc_interface("sysvipc/sem",
> " key semid perms nsems uid gid cuid cgid otime ctime\n",
> IPC_SEM_IDS, sysvipc_sem_proc_show);
> diff --git a/ipc/shm.c b/ipc/shm.c
> index 7fc9f9f..7856952 100644
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -72,12 +72,19 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
> static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
> #endif
>
> -void shm_init_ns(struct ipc_namespace *ns)
> +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> {
> - ns->shm_ctlmax = SHMMAX;
> - ns->shm_ctlall = SHMALL;
> - ns->shm_ctlmni = SHMMNI;
> - ns->shm_rmid_forced = 0;
> + if (old_ns != NULL) {
> + ns->shm_ctlmax = old_ns->shm_ctlmax;
> + ns->shm_ctlall = old_ns->shm_ctlall;
> + ns->shm_ctlmni = old_ns->shm_ctlmni;
> + ns->shm_rmid_forced = old_ns->shm_rmid_forced;
> + } else {
> + ns->shm_ctlmax = SHMMAX;
> + ns->shm_ctlall = SHMALL;
> + ns->shm_ctlmni = SHMMNI;
> + ns->shm_rmid_forced = 0;
> + }
> ns->shm_tot = 0;
> ipc_init_ids(&shm_ids(ns));
> }
> @@ -110,7 +117,7 @@ void shm_exit_ns(struct ipc_namespace *ns)
>
> static int __init ipc_ns_init(void)
> {
> - shm_init_ns(&init_ipc_ns);
> + shm_init_ns(&init_ipc_ns, NULL);
> return 0;
> }
>
> diff --git a/ipc/util.h b/ipc/util.h
> index 1a5a0fc..1be9830 100644
> --- a/ipc/util.h
> +++ b/ipc/util.h
> @@ -30,17 +30,25 @@ static inline void mq_put_mnt(struct ipc_namespace *ns) { }
> #endif
>
> #ifdef CONFIG_SYSVIPC
> -void sem_init_ns(struct ipc_namespace *ns);
> -void msg_init_ns(struct ipc_namespace *ns);
> -void shm_init_ns(struct ipc_namespace *ns);
> +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
>
> void sem_exit_ns(struct ipc_namespace *ns);
> void msg_exit_ns(struct ipc_namespace *ns);
> void shm_exit_ns(struct ipc_namespace *ns);
> #else
> -static inline void sem_init_ns(struct ipc_namespace *ns) { }
> -static inline void msg_init_ns(struct ipc_namespace *ns) { }
> -static inline void shm_init_ns(struct ipc_namespace *ns) { }
> +static inline void sem_init_ns(struct ipc_namespace *ns,
> + struct ipc_namespace *old_ns)
> +{ }
> +
> +static inline void msg_init_ns(struct ipc_namespace *ns,
> + struct ipc_namespace *old_ns)
> +{ }
> +
> +static inline void shm_init_ns(struct ipc_namespace *ns,
> + struct ipc_namespace *old_ns)
> +{ }
>
> static inline void sem_exit_ns(struct ipc_namespace *ns) { }
> static inline void msg_exit_ns(struct ipc_namespace *ns) { }
--
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