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From: pierre.peiffer@bull.net
To: linux-kernel@vger.kernel.org, containers@lists.linux-foundation.org
Subject: [PATCH 2.6.24-rc8-mm1 10/15] (RFC) IPC: new IPC_SETID command to modify an ID
Date: Tue, 29 Jan 2008 17:02:39 +0100	[thread overview]
Message-ID: <20080129162030.964551219@bull.net> (raw)
In-Reply-To: <20080129160229.612172683@bull.net>

[-- Attachment #1: ipc_setid.patch --]
[-- Type: text/plain, Size: 8151 bytes --]

From: Pierre Peiffer <pierre.peiffer@bull.net>

This patch adds a new IPC_SETID command to the System V IPCs set of commands,
which allows to change the ID of an existing IPC.

This command can be used through the semctl/shmctl/msgctl API, with the new
ID passed as the third argument for msgctl and shmctl (instead of a pointer)
and through the fourth argument for semctl.

To be successful, the following rules must be respected:
- the IPC exists
- the user must be allowed to change the IPC attributes regarding the IPC
  permissions.
- the new ID must satisfy the ID computation rule.
- the entry (in the kernel internal table of IPCs) corresponding to the new
  ID must be free.

Signed-off-by: Pierre Peiffer <pierre.peiffer@bull.net>
Acked-by: Serge Hallyn <serue@us.ibm.com>
---

 include/linux/ipc.h      |    9 +++++----
 ipc/compat.c             |    3 +++
 ipc/msg.c                |   27 ++++++++++++++++++++++++++-
 ipc/sem.c                |   27 ++++++++++++++++++++++++++-
 ipc/shm.c                |   27 ++++++++++++++++++++++++++-
 security/selinux/hooks.c |    3 +++
 6 files changed, 89 insertions(+), 7 deletions(-)

Index: b/include/linux/ipc.h
===================================================================
--- a/include/linux/ipc.h
+++ b/include/linux/ipc.h
@@ -35,10 +35,11 @@ struct ipc_perm
  * Control commands used with semctl, msgctl and shmctl 
  * see also specific commands in sem.h, msg.h and shm.h
  */
-#define IPC_RMID 0     /* remove resource */
-#define IPC_SET  1     /* set ipc_perm options */
-#define IPC_STAT 2     /* get ipc_perm options */
-#define IPC_INFO 3     /* see ipcs */
+#define IPC_RMID   0     /* remove resource */
+#define IPC_SET    1     /* set ipc_perm options */
+#define IPC_STAT   2     /* get ipc_perm options */
+#define IPC_INFO   3     /* see ipcs */
+#define IPC_SETID  4     /* set ipc ID */
 
 /*
  * Version flags for semctl, msgctl, and shmctl commands
Index: b/ipc/compat.c
===================================================================
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -253,6 +253,7 @@ long compat_sys_semctl(int first, int se
 	switch (third & (~IPC_64)) {
 	case IPC_INFO:
 	case IPC_RMID:
+	case IPC_SETID:
 	case SEM_INFO:
 	case GETVAL:
 	case GETPID:
@@ -425,6 +426,7 @@ long compat_sys_msgctl(int first, int se
 	switch (second & (~IPC_64)) {
 	case IPC_INFO:
 	case IPC_RMID:
+	case IPC_SETID:
 	case MSG_INFO:
 		err = sys_msgctl(first, second, uptr);
 		break;
@@ -597,6 +599,7 @@ long compat_sys_shmctl(int first, int se
 
 	switch (second & (~IPC_64)) {
 	case IPC_RMID:
+	case IPC_SETID:
 	case SHM_LOCK:
 	case SHM_UNLOCK:
 		err = sys_shmctl(first, second, uptr);
Index: b/ipc/msg.c
===================================================================
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -329,7 +329,8 @@ retry:
 	msg_unlock(msq);
 	up_write(&msg_ids(ns).rw_mutex);
 
-	/* ipc_chid may return -EAGAIN in case of memory requirement */
+	/* msg_chid_nolock may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
 	if (err == -EAGAIN)
 		goto retry;
 
@@ -465,6 +466,9 @@ static int msgctl_down(struct ipc_namesp
 		 */
 		ss_wakeup(&msq->q_senders, 0);
 		break;
+	case IPC_SETID:
+		err = msg_chid_nolock(ns, msq, (int)(long)buf);
+		break;
 	default:
 		err = -EINVAL;
 	}
@@ -475,6 +479,24 @@ out_up:
 	return err;
 }
 
+static int msgctl_setid(struct ipc_namespace *ns, int msqid, int cmd,
+			struct msqid_ds __user *buf, int version)
+{
+	int err;
+retry:
+	err = idr_pre_get(&msg_ids(ns).ipcs_idr, GFP_KERNEL);
+	if (!err)
+		return -ENOMEM;
+
+	err = msgctl_down(ns, msqid, cmd, buf, version);
+
+	/* msgctl_down may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
+	if (err == -EAGAIN)
+		goto retry;
+	return err;
+}
+
 asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
 {
 	struct msg_queue *msq;
@@ -575,6 +597,9 @@ asmlinkage long sys_msgctl(int msqid, in
 	case IPC_RMID:
 		err = msgctl_down(ns, msqid, cmd, buf, version);
 		return err;
+	case IPC_SETID:
+		err = msgctl_setid(ns, msqid, cmd, buf, version);
+		return err;
 	default:
 		return  -EINVAL;
 	}
Index: b/ipc/sem.c
===================================================================
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -608,7 +608,8 @@ retry:
 	sem_unlock(sma);
 	up_write(&sem_ids(ns).rw_mutex);
 
-	/* ipc_chid may return -EAGAIN in case of memory requirement */
+	/* sem_chid_nolock may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
 	if (err == -EAGAIN)
 		goto retry;
 
@@ -935,6 +936,9 @@ static int semctl_down(struct ipc_namesp
 		ipc_update_perm(&semid64.sem_perm, ipcp);
 		sma->sem_ctime = get_seconds();
 		break;
+	case IPC_SETID:
+		err = sem_chid_nolock(ns, sma, (int)arg.val);
+		break;
 	default:
 		err = -EINVAL;
 	}
@@ -946,6 +950,24 @@ out_up:
 	return err;
 }
 
+static int semctl_setid(struct ipc_namespace *ns,  int semid,
+			int cmd, int version, union semun arg)
+{
+	int err;
+retry:
+	err = idr_pre_get(&sem_ids(ns).ipcs_idr, GFP_KERNEL);
+	if (!err)
+		return -ENOMEM;
+
+	err = semctl_down(ns, semid, cmd, version, arg);
+
+	/* semctl_down may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
+	if (err == -EAGAIN)
+		goto retry;
+	return err;
+}
+
 asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg)
 {
 	int err = -EINVAL;
@@ -978,6 +1000,9 @@ asmlinkage long sys_semctl (int semid, i
 	case IPC_SET:
 		err = semctl_down(ns, semid, cmd, version, arg);
 		return err;
+	case IPC_SETID:
+		err = semctl_setid(ns, semid, cmd, version, arg);
+		return err;
 	default:
 		return -EINVAL;
 	}
Index: b/ipc/shm.c
===================================================================
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -202,7 +202,8 @@ retry:
 	shm_unlock(shp);
 	up_write(&shm_ids(ns).rw_mutex);
 
-	/* ipc_chid may return -EAGAIN in case of memory requirement */
+	/* shm_chid_nolock may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
 	if (err == -EAGAIN)
 			goto retry;
 
@@ -679,6 +680,9 @@ static int shmctl_down(struct ipc_namesp
 		ipc_update_perm(&shmid64.shm_perm, ipcp);
 		shp->shm_ctim = get_seconds();
 		break;
+	case IPC_SETID:
+		err = shm_chid_nolock(ns, shp, (int)(long)buf);
+		break;
 	default:
 		err = -EINVAL;
 	}
@@ -689,6 +693,24 @@ out_up:
 	return err;
 }
 
+static int shmctl_setid(struct ipc_namespace *ns, int shmid, int cmd,
+			struct shmid_ds __user *buf, int version)
+{
+	int err;
+retry:
+	err = idr_pre_get(&shm_ids(ns).ipcs_idr, GFP_KERNEL);
+	if (!err)
+		return -ENOMEM;
+
+	err = shmctl_down(ns, shmid, cmd, buf, version);
+
+	/* shmctl_down may return -EAGAIN if there is no more free idr
+	   entry, just go and retry by filling again de idr cache */
+	if (err == -EAGAIN)
+		goto retry;
+	return err;
+}
+
 asmlinkage long sys_shmctl(int shmid, int cmd, struct shmid_ds __user *buf)
 {
 	struct shmid_kernel *shp;
@@ -850,6 +872,9 @@ asmlinkage long sys_shmctl(int shmid, in
 	case IPC_SET:
 		err = shmctl_down(ns, shmid, cmd, buf, version);
 		return err;
+	case IPC_SETID:
+		err = shmctl_setid(ns, shmid, cmd, buf, version);
+		return err;
 	default:
 		return -EINVAL;
 	}
Index: b/security/selinux/hooks.c
===================================================================
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4651,6 +4651,7 @@ static int selinux_msg_queue_msgctl(stru
 		perms = MSGQ__GETATTR | MSGQ__ASSOCIATE;
 		break;
 	case IPC_SET:
+	case IPC_SETID:
 		perms = MSGQ__SETATTR;
 		break;
 	case IPC_RMID:
@@ -4799,6 +4800,7 @@ static int selinux_shm_shmctl(struct shm
 		perms = SHM__GETATTR | SHM__ASSOCIATE;
 		break;
 	case IPC_SET:
+	case IPC_SETID:
 		perms = SHM__SETATTR;
 		break;
 	case SHM_LOCK:
@@ -4910,6 +4912,7 @@ static int selinux_sem_semctl(struct sem
 		perms = SEM__DESTROY;
 		break;
 	case IPC_SET:
+	case IPC_SETID:
 		perms = SEM__SETATTR;
 		break;
 	case IPC_STAT:

-- 
Pierre Peiffer

  parent reply	other threads:[~2008-01-29 16:21 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-01-29 16:02 [PATCH 2.6.24-rc8-mm1 00/15] IPC: code rewrite + new functionalities pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 01/15] IPC/semaphores: code factorisation pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 02/15] IPC/shared memory: introduce shmctl_down pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 03/15] IPC/message queues: introduce msgctl_down pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 04/15] IPC/semaphores: move the rwmutex handling inside semctl_down pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 05/15] IPC/semaphores: remove one unused parameter from semctl_down() pierre.peiffer
2008-01-31  8:32   ` Nadia Derbey
2008-01-31 10:18     ` Pierre Peiffer
2008-01-31 11:30       ` Nadia Derbey
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 06/15] IPC: get rid of the use *_setbuf structure pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 07/15] IPC: introduce ipc_update_perm() pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 08/15] IPC: consolidate all xxxctl_down() functions pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 09/15] (RFC) IPC: new kernel API to change an ID pierre.peiffer
2008-01-29 21:06   ` Alexey Dobriyan
2008-01-30  9:52     ` Pierre Peiffer
2008-01-31  9:00     ` Pierre Peiffer
2008-01-31  9:54       ` Kirill Korotaev
2008-01-31 11:57         ` Pierre Peiffer
2008-01-31 13:11           ` Kirill Korotaev
2008-01-31 16:10             ` Cedric Le Goater
2008-02-04 13:41               ` Kirill Korotaev
2008-02-04 14:06                 ` [Devel] " Pavel Emelyanov
2008-02-04 15:00                   ` Daniel Lezcano
2008-02-04 15:16                     ` Pavel Emelyanov
2008-02-05  9:51           ` Oren Laadan
2008-02-05 18:00             ` Dave Hansen
2008-02-05 18:42             ` Serge E. Hallyn
2008-02-06  2:07               ` Oren Laadan
2008-02-06  5:00                 ` Serge E. Hallyn
2008-02-08 10:12               ` Pierre Peiffer
2008-01-29 16:02 ` pierre.peiffer [this message]
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 11/15] (RFC) IPC: new IPC_SETALL command to modify all settings pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 12/15] (RFC) IPC/semaphores: make use of RCU to free the sem_undo_list pierre.peiffer
2008-01-30 21:26   ` Serge E. Hallyn
2008-01-31  9:52     ` Pierre Peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 13/15] (RFC) IPC/semaphores: per <pid> semundo file in procfs pierre.peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 14/15] (RFC) IPC/semaphores: prepare semundo code to work on another task than current pierre.peiffer
2008-01-30 21:44   ` Serge E. Hallyn
2008-01-31  9:48     ` Pierre Peiffer
2008-01-31 18:01       ` Serge E. Hallyn
2008-02-01 12:09         ` Pierre Peiffer
2008-01-29 16:02 ` [PATCH 2.6.24-rc8-mm1 15/15] (RFC) IPC/semaphores: add write() operation to semundo file in procfs pierre.peiffer
2008-02-02 18:23 ` [PATCH 2.6.24-rc8-mm1 00/15] IPC: code rewrite + new functionalities Pavel Machek
2008-02-04 13:52   ` Pierre Peiffer
2008-02-04 15:44   ` Benjamin Thery
2008-02-04 19:51     ` Pavel Machek

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