diff options
| -rw-r--r-- | ipc/msg.c | 14 | ||||
| -rw-r--r-- | ipc/sem.c | 14 | ||||
| -rw-r--r-- | ipc/shm.c | 39 | ||||
| -rw-r--r-- | ipc/util.c | 78 | ||||
| -rw-r--r-- | ipc/util.h | 18 |
5 files changed, 118 insertions, 45 deletions
diff --git a/ipc/msg.c b/ipc/msg.c index 9f545826bcf..b7274dbf091 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -156,6 +156,13 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) ipc_rmid(&msg_ids(ns), &s->q_perm); } +/** + * newque - Create a new msg queue + * @ns: namespace + * @params: ptr to the structure that contains the key and msgflg + * + * Called with msg_ids.mutex held + */ static int newque(struct ipc_namespace *ns, struct ipc_params *params) { struct msg_queue *msq; @@ -250,8 +257,8 @@ static void expunge_all(struct msg_queue *msq, int res) /* * freeque() wakes up waiters on the sender and receiver waiting queue, - * removes the message queue from message queue ID - * IDR, and cleans up all the messages associated with this queue. + * removes the message queue from message queue ID IDR, and cleans up all the + * messages associated with this queue. * * msg_ids.mutex and the spinlock for this message queue are held * before freeque() is called. msg_ids.mutex remains locked on exit. @@ -278,6 +285,9 @@ static void freeque(struct ipc_namespace *ns, struct msg_queue *msq) ipc_rcu_putref(msq); } +/* + * Called with msg_ids.mutex and ipcp locked. + */ static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) { struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm); diff --git a/ipc/sem.c b/ipc/sem.c index 446c8f51804..45c7e573c20 100644 --- a/ipc/sem.c +++ b/ipc/sem.c @@ -228,6 +228,14 @@ static inline void sem_rmid(struct ipc_namespace *ns, struct sem_array *s) */ #define IN_WAKEUP 1 +/** + * newary - Create a new semaphore set + * @ns: namespace + * @params: ptr to the structure that contains key, semflg and nsems + * + * Called with sem_ids.mutex held + */ + static int newary(struct ipc_namespace *ns, struct ipc_params *params) { int id; @@ -281,6 +289,9 @@ static int newary(struct ipc_namespace *ns, struct ipc_params *params) } +/* + * Called with sem_ids.mutex and ipcp locked. + */ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) { struct sem_array *sma; @@ -289,6 +300,9 @@ static inline int sem_security(struct kern_ipc_perm *ipcp, int semflg) return security_sem_associate(sma, semflg); } +/* + * Called with sem_ids.mutex and ipcp locked. + */ static inline int sem_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params) { diff --git a/ipc/shm.c b/ipc/shm.c index e2de16efe10..f28f2a3163e 100644 --- a/ipc/shm.c +++ b/ipc/shm.c @@ -82,6 +82,10 @@ static void __shm_init_ns(struct ipc_namespace *ns, struct ipc_ids *ids) ipc_init_ids(ids); } +/* + * Called with shm_ids.mutex and the shp structure locked. + * Only shm_ids.mutex remains locked on exit. + */ static void do_shm_rmid(struct ipc_namespace *ns, struct shmid_kernel *shp) { if (shp->shm_nattch){ @@ -182,6 +186,7 @@ static void shm_open(struct vm_area_struct *vma) /* * shm_destroy - free the struct shmid_kernel * + * @ns: namespace * @shp: struct to free * * It has to be called with shp and shm_ids.mutex locked, @@ -343,6 +348,14 @@ static struct vm_operations_struct shm_vm_ops = { #endif }; +/** + * newseg - Create a new shared memory segment + * @ns: namespace + * @params: ptr to the structure that contains key, size and shmflg + * + * Called with shm_ids.mutex held + */ + static int newseg(struct ipc_namespace *ns, struct ipc_params *params) { key_t key = params->key; @@ -428,6 +441,9 @@ no_file: return error; } +/* + * Called with shm_ids.mutex and ipcp locked. + */ static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) { struct shmid_kernel *shp; @@ -436,6 +452,9 @@ static inline int shm_security(struct kern_ipc_perm *ipcp, int shmflg) return security_shm_associate(shp, shmflg); } +/* + * Called with shm_ids.mutex and ipcp locked. + */ static inline int shm_more_checks(struct kern_ipc_perm *ipcp, struct ipc_params *params) { @@ -558,6 +577,9 @@ static inline unsigned long copy_shminfo_to_user(void __user *buf, struct shminf } } +/* + * Called with shm_ids.mutex held + */ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, unsigned long *swp) { @@ -573,18 +595,6 @@ static void shm_get_stat(struct ipc_namespace *ns, unsigned long *rss, struct shmid_kernel *shp; struct inode *inode; - /* - * idr_find() is called via shm_get(), so with shm_ids.mutex - * locked. Since ipc_addid() is also called with - * shm_ids.mutex down, there is no need to add read barriers - * here to gurantee the writes in ipc_addid() are seen in - * order here (for Alpha). - * However idr_find() itself does not necessary require - * ipc_ids.mutex down. So if idr_find() is used by other - * places without ipc_ids.mutex down, then it needs read - * read memory barriers as ipc_lock() does. - */ - shp = idr_find(&shm_ids(ns).ipcs_idr, next_id); if (shp == NULL) continue; @@ -638,8 +648,11 @@ asmlinkage long sys_shmctl (int shmid, int cmd, struct shmid_ds __user *buf) shminfo.shmmin = SHMMIN; if(copy_shminfo_to_user (buf, &shminfo, version)) return -EFAULT; - /* reading a integer is always atomic */ + + mutex_lock(&shm_ids(ns).mutex); err = ipc_get_maxid(&shm_ids(ns)); + mutex_unlock(&shm_ids(ns).mutex); + if(err<0) err = 0; goto out; diff --git a/ipc/util.c b/ipc/util.c index 49e75efe305..fd29246dc3c 100644 --- a/ipc/util.c +++ b/ipc/util.c @@ -194,7 +194,7 @@ void __init ipc_init_proc_interface(const char *path, const char *header, * Requires ipc_ids.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 */ static struct kern_ipc_perm *ipc_findkey(struct ipc_ids *ids, key_t key) @@ -258,10 +258,10 @@ 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 -1 is returned. * * Called with ipc_ids.mutex held. */ @@ -270,10 +270,6 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) { int id, err; - /* - * rcu_dereference()() is not needed here since - * ipc_ids.mutex is held - */ if (size > IPCMNI) size = IPCMNI; @@ -303,12 +299,12 @@ int ipc_addid(struct ipc_ids* ids, struct kern_ipc_perm* new, int size) /** * ipcget_new - create a new ipc object * @ns: namespace - * @ids: identifer set + * @ids: IPC identifer set * @ops: the actual creation routine to call * @params: its parameters * - * This routine is called sys_msgget, sys_semget() and sys_shmget() when - * the key is IPC_PRIVATE + * This routine is called by sys_msgget, sys_semget() and sys_shmget() + * when the key is IPC_PRIVATE. */ int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, struct ipc_ops *ops, struct ipc_params *params) @@ -330,9 +326,16 @@ int ipcget_new(struct ipc_namespace *ns, struct ipc_ids *ids, /** * ipc_check_perms - check security and permissions for an IPC * @ipcp: ipc permission set - * @ids: identifer 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.mutex and ipcp->lock held. */ static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, struct ipc_params *params) @@ -353,12 +356,16 @@ static int ipc_check_perms(struct kern_ipc_perm *ipcp, struct ipc_ops *ops, /** * ipcget_public - get an ipc object or create a new one * @ns: namespace - * @ids: identifer set + * @ids: IPC identifer set * @ops: the actual creation routine to call * @params: its parameters * - * This routine is called sys_msgget, sys_semget() and sys_shmget() when - * the key is not IPC_PRIVATE + * 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. */ int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, struct ipc_ops *ops, struct ipc_params *params) @@ -389,6 +396,10 @@ int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, 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); @@ -401,12 +412,9 @@ int ipcget_public(struct ipc_namespace *ns, struct ipc_ids *ids, /** * 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. */ @@ -558,10 +566,12 @@ 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); @@ -650,7 +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 * @@ -669,6 +679,18 @@ void ipc64_perm_to_ipc_perm (struct ipc64_perm *in, struct ipc_perm *out) out->seq = in->seq; } +/** + * ipc_lock - Lock an ipc structure + * @ids: IPC identifier set + * @id: ipc id to look for + * + * Look for an id in the ipc ids idr and lock the associated ipc object. + * + * ipc_ids.mutex is not necessarily held before this function is called, + * that's why we enter a RCU read section. + * The ipc object is locked on exit. + */ + struct kern_ipc_perm *ipc_lock(struct ipc_ids *ids, int id) { struct kern_ipc_perm *out; @@ -771,8 +793,8 @@ static void *sysvipc_proc_next(struct seq_file *s, void *it, loff_t *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) { @@ -807,7 +829,7 @@ 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); diff --git a/ipc/util.h b/ipc/util.h index 76f8a79902d..99414a36a25 100644 --- a/ipc/util.h +++ b/ipc/util.h @@ -54,7 +54,7 @@ struct ipc_params { * the calls to sys_msgget(), sys_semget(), sys_shmget() * . routine to call to create a new ipc object. Can be one of newque, * newary, newseg - * . routine to call to call to check permissions for a new ipc object. + * . routine to call to check permissions for a new ipc object. * Can be one of security_msg_associate, security_sem_associate, * security_shm_associate * . routine to call for an extra check if needed @@ -88,7 +88,8 @@ int ipc_get_maxid(struct ipc_ids *); /* must be called with both locks acquired. */ void ipc_rmid(struct ipc_ids *, struct kern_ipc_perm *); -int ipcperms (struct kern_ipc_perm *ipcp, short flg); +/* must be called with ipcp locked */ +int ipcperms(struct kern_ipc_perm *ipcp, short flg); /* for rare, potentially huge allocations. * both function can sleep @@ -131,6 +132,9 @@ static inline int ipc_buildid(struct ipc_ids *ids, int id, int seq) return SEQ_MULTIPLIER * seq + id; } +/* + * Must be called with ipcp locked + */ static inline int ipc_checkid(struct ipc_ids *ids, struct kern_ipc_perm *ipcp, int uid) { @@ -168,6 +172,16 @@ static inline struct kern_ipc_perm *ipc_lock_check(struct ipc_ids *ids, return out; } +/** + * 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(). + */ static inline int ipcget(struct ipc_namespace *ns, struct ipc_ids *ids, struct ipc_ops *ops, struct ipc_params *params) { |