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

Manfred Spraul manfred at colorfullife.com
Tue Aug 12 07:29:17 UTC 2014


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 at hallyn.com
Cc: ebiederm at xmission.com
Cc: containers at lists.linux-foundation.org
Cc: mtk.manpages at gmail.com

Signed-off-by: Manfred Spraul <manfred at colorfullife.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) { }
-- 
1.9.3



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