Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759917AbXI1O70 (ORCPT ); Fri, 28 Sep 2007 10:59:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761796AbXI1O65 (ORCPT ); Fri, 28 Sep 2007 10:58:57 -0400 Received: from ecfrec.frec.bull.fr ([129.183.4.8]:34284 "EHLO ecfrec.frec.bull.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1761740AbXI1O6z (ORCPT ); Fri, 28 Sep 2007 10:58:55 -0400 Date: Fri, 28 Sep 2007 16:58:47 +0200 From: Pierre Peiffer To: linux-kernel@vger.kernel.org Cc: containers@lists.osdl.org Subject: [RFC][PATCH 2/2] System V IPC: new IPC_SETID command to modify an ID Message-Id: <20070928165847.44e143e7.Pierre.Peiffer@bull.net> In-Reply-To: <20070928165459.3b5ca2d8.Pierre.Peiffer@bull.net> References: <20070928165459.3b5ca2d8.Pierre.Peiffer@bull.net> X-Mailer: Sylpheed 2.3.1 (GTK+ 2.10.14; i386-redhat-linux-gnu) Mime-Version: 1.0 X-MIMETrack: Itemize by SMTP Server on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 28/09/2007 17:04:58, Serialize by Router on ECN002/FR/BULL(Release 5.0.12 |February 13, 2003) at 28/09/2007 17:04:59, Serialize complete at 28/09/2007 17:04:59 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 8760 Lines: 318 From: Pierre Peiffer 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 --- include/linux/ipc.h | 9 ++++---- ipc/msg.c | 31 +++++++++++++++++++------- ipc/sem.c | 31 +++++++++++++++++++------- ipc/shm.c | 55 ++++++++++++++++++++++++++++++++++++++-------- security/selinux/hooks.c | 3 +++ 5 files changed, 100 insertions(+), 29 deletions(-) diff --git a/include/linux/ipc.h b/include/linux/ipc.h index 3fd3ddd..f1edef5 100644 --- 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 diff --git a/ipc/msg.c b/ipc/msg.c index d9d4093..9671156 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -81,6 +81,8 @@ static struct ipc_ids init_msg_ids; #define msg_buildid(ns, id, seq) \ ipc_buildid(&msg_ids(ns), id, seq) +static long msg_chid_nolock(struct ipc_namespace *ns, struct msg_queue *msq, + int newid); static void freeque (struct ipc_namespace *ns, struct msg_queue *msq, int id); static int newque (struct ipc_namespace *ns, key_t key, int msgflg); #ifdef CONFIG_PROC_FS @@ -382,6 +384,21 @@ copy_msqid_from_user(struct msq_setbuf *out, void __user *buf, int version) } } +static long msg_chid_nolock(struct ipc_namespace *ns, struct msg_queue *msq, + int newid) +{ + long err; + err = ipc_mvid(&msg_ids(ns), msq->q_id, + newid, ns->msg_ctlmni); + + if (err) + return err; + + msq->q_id = newid; + msq->q_ctime = get_seconds(); + return 0; +} + long msg_mvid(struct ipc_namespace *ns, int id, int newid) { long err; @@ -398,14 +415,7 @@ long msg_mvid(struct ipc_namespace *ns, int id, int newid) if (err) goto out_unlock_up; - err = ipc_mvid(&msg_ids(ns), id, - newid, ns->msg_ctlmni); - - if (err) - goto out_unlock_up; - - msq->q_id = newid; - msq->q_ctime = get_seconds(); + err = msg_chid_nolock(ns, msq, newid); out_unlock_up: msg_unlock(msq); @@ -521,6 +531,7 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) if (copy_msqid_from_user(&setbuf, buf, version)) return -EFAULT; break; + case IPC_SETID: case IPC_RMID: break; default: @@ -583,6 +594,10 @@ asmlinkage long sys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf) msg_unlock(msq); break; } + case IPC_SETID: + err = msg_chid_nolock(ns, msq, (int)buf); + msg_unlock(msq); + break; case IPC_RMID: freeque(ns, msq, msqid); break; diff --git a/ipc/sem.c b/ipc/sem.c index 606f2e9..b78b433 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -98,6 +98,8 @@ static struct ipc_ids init_sem_ids; +static long sem_chid_nolock(struct ipc_namespace *ns, struct sem_array *sma, + int newid); static int newary(struct ipc_namespace *, key_t, int, int); static void freeary(struct ipc_namespace *ns, struct sem_array *sma, int id); #ifdef CONFIG_PROC_FS @@ -906,6 +908,10 @@ static int semctl_down(struct ipc_namespace *ns, int semid, int semnum, sem_unlock(sma); err = 0; break; + case IPC_SETID: + err = sem_chid_nolock(ns, sma, (int)arg.val); + sem_unlock(sma); + break; default: sem_unlock(sma); err = -EINVAL; @@ -918,6 +924,21 @@ out_unlock: return err; } +static long sem_chid_nolock(struct ipc_namespace *ns, struct sem_array *sma, + int newid) +{ + long err; + err = ipc_mvid(&sem_ids(ns), sma->sem_id, + newid, ns->sc_semmni); + + if (err) + return err; + + sma->sem_id = newid; + sma->sem_ctime = get_seconds(); + return 0; +} + long sem_mvid(struct ipc_namespace *ns, int id, int newid) { long err; @@ -934,14 +955,7 @@ long sem_mvid(struct ipc_namespace *ns, int id, int newid) if (err) goto out_unlock_up; - err = ipc_mvid(&sem_ids(ns), id, - newid, ns->sc_semmni); - - if (err) - goto out_unlock_up; - - sma->sem_id = newid; - sma->sem_ctime = get_seconds(); + err = sem_chid_nolock(ns, sma, newid); out_unlock_up: sem_unlock(sma); @@ -980,6 +994,7 @@ asmlinkage long sys_semctl (int semid, int semnum, int cmd, union semun arg) return err; case IPC_RMID: case IPC_SET: + case IPC_SETID: mutex_lock(&sem_ids(ns).mutex); err = semctl_down(ns,semid,semnum,cmd,version,arg); mutex_unlock(&sem_ids(ns).mutex); diff --git a/ipc/shm.c b/ipc/shm.c index 5f4bca6..7d4b27d 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -70,6 +70,8 @@ static struct ipc_ids init_shm_ids; static int newseg (struct ipc_namespace *ns, key_t key, int shmflg, size_t size); +static long shm_chid_nolock(struct ipc_namespace *ns, struct shmid_kernel *shp, + int newid); static void shm_open(struct vm_area_struct *vma); static void shm_close(struct vm_area_struct *vma); static void shm_destroy (struct ipc_namespace *ns, struct shmid_kernel *shp); @@ -156,6 +158,21 @@ static inline int shm_addid(struct ipc_namespace *ns, struct shmid_kernel *shp) return ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); } +static long shm_chid_nolock(struct ipc_namespace *ns, struct shmid_kernel *shp, + int newid) +{ + long err; + err = ipc_mvid(&shm_ids(ns), shp->id, + newid, ns->shm_ctlmni); + + if (err) + return err; + + shp->id = newid; + shp->shm_ctim = get_seconds(); + return 0; +} + long shm_mvid(struct ipc_namespace *ns, int id, int newid) { long err; @@ -172,14 +189,7 @@ long shm_mvid(struct ipc_namespace *ns, int id, int newid) if (err) goto out_unlock_up; - err = ipc_mvid(&shm_ids(ns), id, - newid, ns->shm_ctlmni); - - if (err) - goto out_unlock_up; - - shp->id = newid; - shp->shm_ctim = get_seconds(); + err = shm_chid_nolock(ns, shp, newid); out_unlock_up: shm_unlock(shp); @@ -839,12 +849,39 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) break; } + case IPC_SETID: + { + mutex_lock(&shm_ids(ns).mutex); + shp = shm_lock(ns, shmid); + err = -EINVAL; + if (shp == NULL) + goto out_up; + err = shm_checkid(ns, shp, shmid); + if (err) + goto out_unlock_up; + err = audit_ipc_obj(&(shp->shm_perm)); + if (err) + goto out_unlock_up; + + err = -EPERM; + if (current->euid != shp->shm_perm.uid && + current->euid != shp->shm_perm.cuid && + !capable(CAP_SYS_ADMIN)) + goto out_unlock_up; + + err = security_shm_shmctl(shp, cmd); + if (err) + goto out_unlock_up; + + err = shm_chid_nolock(ns, shp, (int)buf); + break; + } + default: err = -EINVAL; goto out; } - err = 0; out_unlock_up: shm_unlock(shp); out_up: diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index 0753b20..b4a2899 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4163,6 +4163,7 @@ static int selinux_msg_queue_msgctl(struct msg_queue *msq, int cmd) perms = MSGQ__GETATTR | MSGQ__ASSOCIATE; break; case IPC_SET: + case IPC_SETID: perms = MSGQ__SETATTR; break; case IPC_RMID: @@ -4311,6 +4312,7 @@ static int selinux_shm_shmctl(struct shmid_kernel *shp, int cmd) perms = SHM__GETATTR | SHM__ASSOCIATE; break; case IPC_SET: + case IPC_SETID: perms = SHM__SETATTR; break; case SHM_LOCK: @@ -4422,6 +4424,7 @@ static int selinux_sem_semctl(struct sem_array *sma, int cmd) perms = SEM__DESTROY; break; case IPC_SET: + case IPC_SETID: perms = SEM__SETATTR; break; case IPC_STAT: -- Pierre - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/