3.2.72-rc1 review patch. If anyone has any objections, please let me know.
------------------ From: Linus Torvalds <[email protected]> commit b9a532277938798b53178d5a66af6e2915cb27cf upstream. As reported by Dmitry Vyukov, we really shouldn't do ipc_addid() before having initialized the IPC object state. Yes, we initialize the IPC object in a locked state, but with all the lockless RCU lookup work, that IPC object lock no longer means that the state cannot be seen. We already did this for the IPC semaphore code (see commit e8577d1f0329: "ipc/sem.c: fully initialize sem_array before making it visible") but we clearly forgot about msg and shm. Reported-by: Dmitry Vyukov <[email protected]> Cc: Manfred Spraul <[email protected]> Cc: Davidlohr Bueso <[email protected]> Cc: [email protected] Signed-off-by: Linus Torvalds <[email protected]> [bwh: Backported to 3.2: - Adjust context - The error path being moved looks a little different] Signed-off-by: Ben Hutchings <[email protected]> --- --- a/ipc/msg.c +++ b/ipc/msg.c @@ -198,6 +198,15 @@ static int newque(struct ipc_namespace * return retval; } + msq->q_stime = msq->q_rtime = 0; + msq->q_ctime = get_seconds(); + msq->q_cbytes = msq->q_qnum = 0; + msq->q_qbytes = ns->msg_ctlmnb; + msq->q_lspid = msq->q_lrpid = 0; + INIT_LIST_HEAD(&msq->q_messages); + INIT_LIST_HEAD(&msq->q_receivers); + INIT_LIST_HEAD(&msq->q_senders); + /* * ipc_addid() locks msq */ @@ -208,15 +217,6 @@ static int newque(struct ipc_namespace * return id; } - msq->q_stime = msq->q_rtime = 0; - msq->q_ctime = get_seconds(); - msq->q_cbytes = msq->q_qnum = 0; - msq->q_qbytes = ns->msg_ctlmnb; - msq->q_lspid = msq->q_lrpid = 0; - INIT_LIST_HEAD(&msq->q_messages); - INIT_LIST_HEAD(&msq->q_receivers); - INIT_LIST_HEAD(&msq->q_senders); - msg_unlock(msq); return msq->q_perm.id; --- a/ipc/shm.c +++ b/ipc/shm.c @@ -498,12 +498,6 @@ static int newseg(struct ipc_namespace * if (IS_ERR(file)) goto no_file; - id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); - if (id < 0) { - error = id; - goto no_id; - } - shp->shm_cprid = task_tgid_vnr(current); shp->shm_lprid = 0; shp->shm_atim = shp->shm_dtim = 0; @@ -512,6 +506,13 @@ static int newseg(struct ipc_namespace * shp->shm_nattch = 0; shp->shm_file = file; shp->shm_creator = current; + + id = ipc_addid(&shm_ids(ns), &shp->shm_perm, ns->shm_ctlmni); + if (id < 0) { + error = id; + goto no_id; + } + /* * shmid gets reported as "inode#" in /proc/pid/maps. * proc-ps tools use this. Changing this will break them. --- a/ipc/util.c +++ b/ipc/util.c @@ -264,6 +264,10 @@ int ipc_addid(struct ipc_ids* ids, struc rcu_read_lock(); spin_lock(&new->lock); + current_euid_egid(&euid, &egid); + new->cuid = new->uid = euid; + new->gid = new->cgid = egid; + err = idr_get_new(&ids->ipcs_idr, new, &id); if (err) { spin_unlock(&new->lock); @@ -273,10 +277,6 @@ int ipc_addid(struct ipc_ids* ids, struc ids->in_use++; - current_euid_egid(&euid, &egid); - new->cuid = new->uid = euid; - new->gid = new->cgid = egid; - new->seq = ids->seq++; if(ids->seq > ids->seq_max) ids->seq = 0; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
