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(-) 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/msg.c =================================================================== --- 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 @@ -384,6 +386,21 @@ copy_msqid_from_user(struct msq_setbuf * } } +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; @@ -400,14 +417,7 @@ long msg_mvid(struct ipc_namespace *ns, 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); @@ -523,6 +533,7 @@ asmlinkage long sys_msgctl(int msqid, in if (copy_msqid_from_user(&setbuf, buf, version)) return -EFAULT; break; + case IPC_SETID: case IPC_RMID: break; default: @@ -585,6 +596,10 @@ asmlinkage long sys_msgctl(int msqid, in 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; Index: b/ipc/sem.c =================================================================== --- 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 @@ -908,6 +910,10 @@ static int semctl_down(struct ipc_namesp 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; @@ -920,6 +926,21 @@ 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; @@ -936,14 +957,7 @@ long sem_mvid(struct ipc_namespace *ns, 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); @@ -982,6 +996,7 @@ asmlinkage long sys_semctl (int semid, i 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); Index: b/security/selinux/hooks.c =================================================================== --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -4152,6 +4152,7 @@ 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: @@ -4300,6 +4301,7 @@ 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: @@ -4411,6 +4413,7 @@ static int selinux_sem_semctl(struct sem perms = SEM__DESTROY; break; case IPC_SET: + case IPC_SETID: perms = SEM__SETATTR; break; case IPC_STAT: Index: b/ipc/shm.c =================================================================== --- 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); @@ -158,6 +160,21 @@ static inline int shm_addid(struct ipc_n 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; @@ -174,14 +191,7 @@ long shm_mvid(struct ipc_namespace *ns, 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, i 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: -- Pierre Peiffer _______________________________________________ Containers mailing list Containers@lists.linux-foundation.org https://lists.linux-foundation.org/mailman/listinfo/containers