X-Git-Url: http://ftp.safe.ca/?a=blobdiff_plain;f=ipc%2Futil.c;h=79ce84e890f72b153ca4f77ee7abeec3a6aed496;hb=f1eb1332b8f07e937add24c6fd2ac40b8737a2f4;hp=2a205875d277bcce202306124a332cbb1fa07c36;hpb=7ca7e564e049d8b350ec9d958ff25eaa24226352;p=safe%2Fjmp%2Flinux-2.6 diff --git a/ipc/util.c b/ipc/util.c index 2a20587..79ce84e 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -32,6 +32,9 @@ #include #include #include +#include +#include +#include #include @@ -44,77 +47,54 @@ struct ipc_proc_iface { int (*show)(struct seq_file *, void *); }; -struct ipc_namespace init_ipc_ns = { - .kref = { - .refcount = ATOMIC_INIT(2), - }, -}; +#ifdef CONFIG_MEMORY_HOTPLUG -static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) +static void ipc_memory_notifier(struct work_struct *work) { - int err; - struct ipc_namespace *ns; - - err = -ENOMEM; - ns = kmalloc(sizeof(struct ipc_namespace), GFP_KERNEL); - if (ns == NULL) - goto err_mem; - - err = sem_init_ns(ns); - if (err) - goto err_sem; - err = msg_init_ns(ns); - if (err) - goto err_msg; - err = shm_init_ns(ns); - if (err) - goto err_shm; - - kref_init(&ns->kref); - return ns; - -err_shm: - msg_exit_ns(ns); -err_msg: - sem_exit_ns(ns); -err_sem: - kfree(ns); -err_mem: - return ERR_PTR(err); + ipcns_notify(IPCNS_MEMCHANGED); } -struct ipc_namespace *copy_ipcs(unsigned long flags, struct ipc_namespace *ns) -{ - struct ipc_namespace *new_ns; - - BUG_ON(!ns); - get_ipc_ns(ns); +static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier); - if (!(flags & CLONE_NEWIPC)) - return ns; - new_ns = clone_ipc_ns(ns); - - put_ipc_ns(ns); - return new_ns; -} - -void free_ipc_ns(struct kref *kref) +static int ipc_memory_callback(struct notifier_block *self, + unsigned long action, void *arg) { - struct ipc_namespace *ns; + switch (action) { + case MEM_ONLINE: /* memory successfully brought online */ + case MEM_OFFLINE: /* or offline: it's time to recompute msgmni */ + /* + * This is done by invoking the ipcns notifier chain with the + * IPC_MEMCHANGED event. + * In order not to keep the lock on the hotplug memory chain + * for too long, queue a work item that will, when waken up, + * activate the ipcns notification chain. + * No need to keep several ipc work items on the queue. + */ + if (!work_pending(&ipc_memory_wq)) + schedule_work(&ipc_memory_wq); + break; + case MEM_GOING_ONLINE: + case MEM_GOING_OFFLINE: + case MEM_CANCEL_ONLINE: + case MEM_CANCEL_OFFLINE: + default: + break; + } - ns = container_of(kref, struct ipc_namespace, kref); - sem_exit_ns(ns); - msg_exit_ns(ns); - shm_exit_ns(ns); - kfree(ns); + return NOTIFY_OK; } +#endif /* CONFIG_MEMORY_HOTPLUG */ + /** * ipc_init - initialise IPC subsystem * * The various system5 IPC resources (semaphores, messages and shared * memory) are initialised + * A callback routine is registered into the memory hotplug notifier + * chain: since msgmni scales to lowmem this callback routine will be + * called upon successful memory add / remove to recompute msmgni. */ static int __init ipc_init(void) @@ -122,6 +102,8 @@ static int __init ipc_init(void) sem_init(); msg_init(); shm_init(); + hotplug_memory_notifier(ipc_memory_callback, IPC_CALLBACK_PRI); + register_ipcns_notifier(&init_ipc_ns); return 0; } __initcall(ipc_init); @@ -136,14 +118,14 @@ __initcall(ipc_init); void ipc_init_ids(struct ipc_ids *ids) { - mutex_init(&ids->mutex); + init_rwsem(&ids->rw_mutex); ids->in_use = 0; ids->seq = 0; { int seq_limit = INT_MAX/SEQ_MULTIPLIER; - if(seq_limit > USHRT_MAX) - ids->seq_max = USHRT_MAX; + if (seq_limit > USHORT_MAX) + ids->seq_max = USHORT_MAX; else ids->seq_max = seq_limit; } @@ -174,13 +156,12 @@ void __init ipc_init_proc_interface(const char *path, const char *header, iface->ids = ids; iface->show = show; - pde = create_proc_entry(path, - S_IRUGO, /* world readable */ - NULL /* parent dir */); - if (pde) { - pde->data = iface; - pde->proc_fops = &sysvipc_proc_fops; - } else { + pde = proc_create_data(path, + S_IRUGO, /* world readable */ + NULL, /* parent dir */ + &sysvipc_proc_fops, + iface); + if (!pde) { kfree(iface); } } @@ -191,13 +172,13 @@ void __init ipc_init_proc_interface(const char *path, const char *header, * @ids: Identifier set * @key: The key to find * - * Requires ipc_ids.mutex locked. + * Requires ipc_ids.rw_mutex locked. * Returns the LOCKED pointer to the ipc structure if found or NULL * if not. - * If key is found ipc contains its ipc structure + * If key is found ipc points to the owning ipc structure */ -struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) +static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) { struct kern_ipc_perm *ipc; int next_id; @@ -225,7 +206,7 @@ struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) * ipc_get_maxid - get the last assigned id * @ids: IPC identifier set * - * Called with ipc_ids.mutex held. + * Called with ipc_ids.rw_mutex held. */ int ipc_get_maxid(struct ipc_ids *ids) @@ -258,63 +239,188 @@ int ipc_get_maxid(struct ipc_ids *ids) * @new: new IPC permission set * @size: limit for the number of used ids * - * Add an entry 'new' to the IPC idr. The permissions object is + * Add an entry 'new' to the IPC ids idr. The permissions object is * initialised and the first free entry is set up and the id assigned - * is returned. The list is returned in a locked state on success. - * On failure the list is not locked and -1 is returned. + * is returned. The 'new' entry is returned in a locked state on success. + * On failure the entry is not locked and a negative err-code is returned. * - * Called with ipc_ids.mutex held. + * Called with ipc_ids.rw_mutex held as a writer. */ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) { + uid_t euid; + gid_t egid; int id, err; - /* - * rcu_dereference()() is not needed here since - * ipc_ids.mutex is held - */ if (size > IPCMNI) size = IPCMNI; if (ids->in_use >= size) - return -1; + return -ENOSPC; + + spin_lock_init(&new->lock); + new->deleted = 0; + rcu_read_lock(); + spin_lock(&new->lock); err = idr_get_new(&ids->ipcs_idr, new, &id); - if (err) - return -1; + if (err) { + spin_unlock(&new->lock); + rcu_read_unlock(); + return err; + } ids->in_use++; - new->cuid = new->uid = current->euid; - new->gid = new->cgid = current->egid; + 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; - spin_lock_init(&new->lock); - new->deleted = 0; - rcu_read_lock(); - spin_lock(&new->lock); + new->id = ipc_buildid(id, new->seq); return id; } /** + * ipcget_new - create a new ipc object + * @ns: namespace + * @ids: IPC identifer set + * @ops: the actual creation routine to call + * @params: its parameters + * + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is IPC_PRIVATE. + */ +static int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, + struct ipc_ops *ops, struct ipc_params *params) +{ + int err; +retry: + err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); + + if (!err) + return -ENOMEM; + + down_write(&ids->rw_mutex); + err = ops->getnew(ns, params); + up_write(&ids->rw_mutex); + + if (err == -EAGAIN) + goto retry; + + return err; +} + +/** + * ipc_check_perms - check security and permissions for an IPC + * @ipcp: ipc permission set + * @ops: the actual security routine to call + * @params: its parameters + * + * This routine is called by sys_msgget(), sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE and that key already exists in the + * ids IDR. + * + * On success, the IPC id is returned. + * + * It is called with ipc_ids.rw_mutex and ipcp->lock held. + */ +static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, + struct ipc_params *params) +{ + int err; + + if (ipcperms(ipcp, params->flg)) + err = -EACCES; + else { + err = ops->associate(ipcp, params->flg); + if (!err) + err = ipcp->id; + } + + return err; +} + +/** + * ipcget_public - get an ipc object or create a new one + * @ns: namespace + * @ids: IPC identifer set + * @ops: the actual creation routine to call + * @params: its parameters + * + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is not IPC_PRIVATE. + * It adds a new entry if the key is not found and does some permission + * / security checkings if the key is found. + * + * On success, the ipc id is returned. + */ +static int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, + struct ipc_ops *ops, struct ipc_params *params) +{ + struct kern_ipc_perm *ipcp; + int flg = params->flg; + int err; +retry: + err = idr_pre_get(&ids->ipcs_idr, GFP_KERNEL); + + /* + * Take the lock as a writer since we are potentially going to add + * a new entry + read locks are not "upgradable" + */ + down_write(&ids->rw_mutex); + ipcp = ipc_findkey(ids, params->key); + if (ipcp == NULL) { + /* key not used */ + if (!(flg & IPC_CREAT)) + err = -ENOENT; + else if (!err) + err = -ENOMEM; + else + err = ops->getnew(ns, params); + } else { + /* ipc object has been locked by ipc_findkey() */ + + if (flg & IPC_CREAT && flg & IPC_EXCL) + err = -EEXIST; + else { + err = 0; + if (ops->more_checks) + err = ops->more_checks(ipcp, params); + if (!err) + /* + * ipc_check_perms returns the IPC id on + * success + */ + err = ipc_check_perms(ipcp, ops, params); + } + ipc_unlock(ipcp); + } + up_write(&ids->rw_mutex); + + if (err == -EAGAIN) + goto retry; + + return err; +} + + +/** * ipc_rmid - remove an IPC identifier - * @ids: identifier set - * @id: ipc perm structure containing the identifier to remove + * @ids: IPC identifier set + * @ipcp: ipc perm structure containing the identifier to remove * - * The identifier must be valid, and in use. The kernel will panic if - * fed an invalid identifier. The entry is removed and internal - * variables recomputed. - * ipc_ids.mutex and the spinlock for this ID are held before this - * function is called, and remain locked on the exit. + * ipc_ids.rw_mutex (as a writer) and the spinlock for this ID are held + * before this function is called, and remain locked on the exit. */ void ipc_rmid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp) { - int lid = ipcp->id % SEQ_MULTIPLIER; + int lid = ipcid_to_idx(ipcp->id); idr_remove(&ids->ipcs_idr, lid); @@ -459,10 +565,12 @@ static void ipc_do_vfree(struct work_struct *work) */ static void ipc_schedule_free(struct rcu_head *head) { - struct ipc_rcu_grace *grace = - container_of(head, struct ipc_rcu_grace, rcu); - struct ipc_rcu_sched *sched = - container_of(&(grace->data[0]), struct ipc_rcu_sched, data[0]); + struct ipc_rcu_grace *grace; + struct ipc_rcu_sched *sched; + + grace = container_of(head, struct ipc_rcu_grace, rcu); + sched = container_of(&(grace->data[0]), struct ipc_rcu_sched, + data[0]); INIT_WORK(&sched->work, ipc_do_vfree); schedule_work(&sched->work); @@ -506,13 +614,14 @@ void ipc_rcu_putref(void *ptr) int ipcperms (struct kern_ipc_perm *ipcp, short flag) { /* flag will most probably be 0 or S_...UGO from */ - int requested_mode, granted_mode, err; + uid_t euid = current_euid(); + int requested_mode, granted_mode; - if (unlikely((err = audit_ipc_obj(ipcp)))) - return err; + audit_ipc_obj(ipcp); requested_mode = (flag >> 6) | (flag >> 3) | flag; granted_mode = ipcp->mode; - if (current->euid == ipcp->cuid || current->euid == ipcp->uid) + if (euid == ipcp->cuid || + euid == ipcp->uid) granted_mode >>= 6; else if (in_group_p(ipcp->cgid) || in_group_p(ipcp->gid)) granted_mode >>= 3; @@ -551,7 +660,7 @@ void kernel_to_ipc64_perm (struct kern_ipc_perm *in, struct ipc64_perm *out) } /** - * ipc64_perm_to_ipc_perm - convert old ipc permissions to new + * ipc64_perm_to_ipc_perm - convert new ipc permissions to old * @in: new style IPC permissions * @out: old style IPC permissions * @@ -570,35 +679,26 @@ void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) out->seq = in->seq; } -/* - * So far only shm_get_stat() calls ipc_get() via shm_get(), so ipc_get() - * is called with shm_ids.mutex locked. Since grow_ary() is also called with - * shm_ids.mutex down(for Shared Memory), there is no need to add read - * barriers here to gurantee the writes in grow_ary() are seen in order - * here (for Alpha). +/** + * ipc_lock - Lock an ipc structure without rw_mutex held + * @ids: IPC identifier set + * @id: ipc id to look for * - * However ipc_get() itself does not necessary require ipc_ids.mutex down. So - * if in the future ipc_get() is used by other places without ipc_ids.mutex - * down, then ipc_get() needs read memery barriers as ipc_lock() does. + * Look for an id in the ipc ids idr and lock the associated ipc object. + * + * The ipc object is locked on exit. */ -struct kern_ipc_perm *ipc_get(struct ipc_ids *ids, int id) -{ - struct kern_ipc_perm *out; - int lid = id % SEQ_MULTIPLIER; - out = idr_find(&ids->ipcs_idr, lid); - return out; -} struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) { struct kern_ipc_perm *out; - int lid = id % SEQ_MULTIPLIER; + int lid = ipcid_to_idx(id); rcu_read_lock(); out = idr_find(&ids->ipcs_idr, lid); if (out == NULL) { rcu_read_unlock(); - return NULL; + return ERR_PTR(-EINVAL); } spin_lock(&out->lock); @@ -609,34 +709,105 @@ struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) if (out->deleted) { spin_unlock(&out->lock); rcu_read_unlock(); - return NULL; + return ERR_PTR(-EINVAL); } return out; } -void ipc_lock_by_ptr(struct kern_ipc_perm *perm) +struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, int id) { - rcu_read_lock(); - spin_lock(&perm->lock); + struct kern_ipc_perm *out; + + out = ipc_lock(ids, id); + if (IS_ERR(out)) + return out; + + if (ipc_checkid(out, id)) { + ipc_unlock(out); + return ERR_PTR(-EIDRM); + } + + return out; } -void ipc_unlock(struct kern_ipc_perm* perm) +/** + * ipcget - Common sys_*get() code + * @ns : namsepace + * @ids : IPC identifier set + * @ops : operations to be called on ipc object creation, permission checks + * and further checks + * @params : the parameters needed by the previous operations. + * + * Common routine called by sys_msgget(), sys_semget() and sys_shmget(). + */ +int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, + struct ipc_ops *ops, struct ipc_params *params) { - spin_unlock(&perm->lock); - rcu_read_unlock(); + if (params->key == IPC_PRIVATE) + return ipcget_new(ns, ids, ops, params); + else + return ipcget_public(ns, ids, ops, params); } -int ipc_buildid(struct ipc_ids* ids, int id, int seq) +/** + * ipc_update_perm - update the permissions of an IPC. + * @in: the permission given as input. + * @out: the permission of the ipc to set. + */ +void ipc_update_perm(struct ipc64_perm *in, struct kern_ipc_perm *out) { - return SEQ_MULTIPLIER*seq + id; + out->uid = in->uid; + out->gid = in->gid; + out->mode = (out->mode & ~S_IRWXUGO) + | (in->mode & S_IRWXUGO); } -int ipc_checkid(struct ipc_ids* ids, struct kern_ipc_perm* ipcp, int uid) +/** + * ipcctl_pre_down - retrieve an ipc and check permissions for some IPC_XXX cmd + * @ids: the table of ids where to look for the ipc + * @id: the id of the ipc to retrieve + * @cmd: the cmd to check + * @perm: the permission to set + * @extra_perm: one extra permission parameter used by msq + * + * This function does some common audit and permissions check for some IPC_XXX + * cmd and is called from semctl_down, shmctl_down and msgctl_down. + * It must be called without any lock held and + * - retrieves the ipc with the given id in the given table. + * - performs some audit and permission check, depending on the given cmd + * - returns the ipc with both ipc and rw_mutex locks held in case of success + * or an err-code without any lock held otherwise. + */ +struct kern_ipc_perm *ipcctl_pre_down(struct ipc_ids *ids, int id, int cmd, + struct ipc64_perm *perm, int extra_perm) { - if(uid/SEQ_MULTIPLIER != ipcp->seq) - return 1; - return 0; + struct kern_ipc_perm *ipcp; + uid_t euid; + int err; + + down_write(&ids->rw_mutex); + ipcp = ipc_lock_check(ids, id); + if (IS_ERR(ipcp)) { + err = PTR_ERR(ipcp); + goto out_up; + } + + audit_ipc_obj(ipcp); + if (cmd == IPC_SET) + audit_ipc_set_perm(extra_perm, perm->uid, + perm->gid, perm->mode); + + euid = current_euid(); + if (euid == ipcp->cuid || + euid == ipcp->uid || capable(CAP_SYS_ADMIN)) + return ipcp; + + err = -EPERM; + ipc_unlock(ipcp); +out_up: + up_write(&ids->rw_mutex); + return ERR_PTR(err); } #ifdef __ARCH_WANT_IPC_PARSE_VERSION @@ -672,8 +843,8 @@ struct ipc_proc_iter { /* * This routine locks the ipc structure found at least at position pos. */ -struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, - loff_t *new_pos) +static struct kern_ipc_perm *sysvipc_find_ipc(struct ipc_ids *ids, loff_t pos, + loff_t *new_pos) { struct kern_ipc_perm *ipc; int total, id; @@ -711,12 +882,12 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *pos) if (ipc && ipc != SEQ_START_TOKEN) ipc_unlock(ipc); - return sysvipc_find_ipc(iter->ns->ids[iface->ids], *pos, pos); + return sysvipc_find_ipc(&iter->ns->ids[iface->ids], *pos, pos); } /* - * File positions: pos 0 -> header, pos n -> ipc id + 1. - * SeqFile iterator: iterator value locked shp or SEQ_TOKEN_START. + * File positions: pos 0 -> header, pos n -> ipc id = n - 1. + * SeqFile iterator: iterator value locked ipc pointer or SEQ_TOKEN_START. */ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) { @@ -724,13 +895,13 @@ static void *sysvipc_proc_start(struct seq_file *s, loff_t *pos) struct ipc_proc_iface *iface = iter->iface; struct ipc_ids *ids; - ids = iter->ns->ids[iface->ids]; + ids = &iter->ns->ids[iface->ids]; /* * Take the lock - this will be released by the corresponding * call to stop(). */ - mutex_lock(&ids->mutex); + down_read(&ids->rw_mutex); /* pos < 0 is invalid */ if (*pos < 0) @@ -751,13 +922,13 @@ static void sysvipc_proc_stop(struct seq_file *s, void *it) struct ipc_proc_iface *iface = iter->iface; struct ipc_ids *ids; - /* If we had a locked segment, release it */ + /* If we had a locked structure, release it */ if (ipc && ipc != SEQ_START_TOKEN) ipc_unlock(ipc); - ids = iter->ns->ids[iface->ids]; + ids = &iter->ns->ids[iface->ids]; /* Release the lock we took in start() */ - mutex_unlock(&ids->mutex); + up_read(&ids->rw_mutex); } static int sysvipc_proc_show(struct seq_file *s, void *it) @@ -771,7 +942,7 @@ static int sysvipc_proc_show(struct seq_file *s, void *it) return iface->show(s, it); } -static struct seq_operations sysvipc_proc_seqops = { +static const struct seq_operations sysvipc_proc_seqops = { .start = sysvipc_proc_start, .stop = sysvipc_proc_stop, .next = sysvipc_proc_next,