[PATCH 3/3] ipc namespace: copy settings from parent namespace

From: Manfred Spraul
Date: Tue Aug 12 2014 - 03:30:41 EST

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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.

The patch updates
- SysV msg
- SysV sem
- SysV shm
- POSIX mqueues

Cc: serge@xxxxxxxxxx
Cc: ebiederm@xxxxxxxxxxxx
Cc: containers@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: mtk.manpages@xxxxxxxxx

Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx>
---
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) { }
--
1.9.3

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Next message: Manfred Spraul: "[PATCH 2/3] ipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM"
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