X-Git-Url: https://git.stricted.de/?p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git;a=blobdiff_plain;f=ipc%2Fmsg.c;h=32aaaab15c5c46ae12c90d58693df7a0bb47d9b8;hp=725a7b74fad8cf8f12a06b3fa480af04c1e36066;hb=HEAD;hpb=7b527fcdfdc6c4edfc6dad3bae254679ed63fc55 diff --git a/ipc/msg.c b/ipc/msg.c index 725a7b74fad8..32aaaab15c5c 100644 --- a/ipc/msg.c +++ b/ipc/msg.c @@ -70,8 +70,6 @@ struct msg_sender { #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS]) -#define msg_unlock(msq) ipc_unlock(&(msq)->q_perm) - static void freeque(struct ipc_namespace *, struct kern_ipc_perm *); static int newque(struct ipc_namespace *, struct ipc_params *); #ifdef CONFIG_PROC_FS @@ -141,31 +139,6 @@ void __init msg_init(void) IPC_MSG_IDS, sysvipc_msg_proc_show); } -/* - * msg_lock_(check_) routines are called in the paths where the rw_mutex - * is not held. - */ -static inline struct msg_queue *msg_lock(struct ipc_namespace *ns, int id) -{ - struct kern_ipc_perm *ipcp = ipc_lock(&msg_ids(ns), id); - - if (IS_ERR(ipcp)) - return (struct msg_queue *)ipcp; - - return container_of(ipcp, struct msg_queue, q_perm); -} - -static inline struct msg_queue *msg_lock_check(struct ipc_namespace *ns, - int id) -{ - struct kern_ipc_perm *ipcp = ipc_lock_check(&msg_ids(ns), id); - - if (IS_ERR(ipcp)) - return (struct msg_queue *)ipcp; - - return container_of(ipcp, struct msg_queue, q_perm); -} - static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id) { struct kern_ipc_perm *ipcp = ipc_obtain_object(&msg_ids(ns), id); @@ -192,12 +165,21 @@ static inline void msg_rmid(struct ipc_namespace *ns, struct msg_queue *s) ipc_rmid(&msg_ids(ns), &s->q_perm); } +static void msg_rcu_free(struct rcu_head *head) +{ + struct ipc_rcu *p = container_of(head, struct ipc_rcu, rcu); + struct msg_queue *msq = ipc_rcu_to_struct(p); + + security_msg_queue_free(msq); + ipc_rcu_free(head); +} + /** * newque - Create a new msg queue * @ns: namespace * @params: ptr to the structure that contains the key and msgflg * - * Called with msg_ids.rw_mutex held (writer) + * Called with msg_ids.rwsem held (writer) */ static int newque(struct ipc_namespace *ns, struct ipc_params *params) { @@ -216,18 +198,10 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) msq->q_perm.security = NULL; retval = security_msg_queue_alloc(msq); if (retval) { - ipc_rcu_putref(msq); + ipc_rcu_putref(msq, ipc_rcu_free); return retval; } - /* ipc_addid() locks msq upon success. */ - id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); - if (id < 0) { - security_msg_queue_free(msq); - ipc_rcu_putref(msq); - return id; - } - msq->q_stime = msq->q_rtime = 0; msq->q_ctime = get_seconds(); msq->q_cbytes = msq->q_qnum = 0; @@ -237,6 +211,13 @@ static int newque(struct ipc_namespace *ns, struct ipc_params *params) INIT_LIST_HEAD(&msq->q_receivers); INIT_LIST_HEAD(&msq->q_senders); + /* ipc_addid() locks msq upon success. */ + id = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni); + if (id < 0) { + ipc_rcu_putref(msq, msg_rcu_free); + return id; + } + ipc_unlock_object(&msq->q_perm); rcu_read_unlock(); @@ -284,8 +265,8 @@ static void expunge_all(struct msg_queue *msq, int res) * removes the message queue from message queue ID IDR, and cleans up all the * messages associated with this queue. * - * msg_ids.rw_mutex (writer) and the spinlock for this message queue are held - * before freeque() is called. msg_ids.rw_mutex remains locked on exit. + * msg_ids.rwsem (writer) and the spinlock for this message queue are held + * before freeque() is called. msg_ids.rwsem remains locked on exit. */ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) { @@ -295,19 +276,19 @@ static void freeque(struct ipc_namespace *ns, struct kern_ipc_perm *ipcp) expunge_all(msq, -EIDRM); ss_wakeup(&msq->q_senders, 1); msg_rmid(ns, msq); - msg_unlock(msq); + ipc_unlock_object(&msq->q_perm); + rcu_read_unlock(); list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) { atomic_dec(&ns->msg_hdrs); free_msg(msg); } atomic_sub(msq->q_cbytes, &ns->msg_bytes); - security_msg_queue_free(msq); - ipc_rcu_putref(msq); + ipc_rcu_putref(msq, msg_rcu_free); } /* - * Called with msg_ids.rw_mutex and ipcp locked. + * Called with msg_ids.rwsem and ipcp locked. */ static inline int msg_security(struct kern_ipc_perm *ipcp, int msgflg) { @@ -411,9 +392,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version) } /* - * This function handles some msgctl commands which require the rw_mutex + * This function handles some msgctl commands which require the rwsem * to be held in write mode. - * NOTE: no locks must be held, the rw_mutex is taken inside this function. + * NOTE: no locks must be held, the rwsem is taken inside this function. */ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, struct msqid_ds __user *buf, int version) @@ -428,7 +409,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd, return -EFAULT; } - down_write(&msg_ids(ns).rw_mutex); + down_write(&msg_ids(ns).rwsem); rcu_read_lock(); ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd, @@ -484,7 +465,7 @@ out_unlock0: out_unlock1: rcu_read_unlock(); out_up: - up_write(&msg_ids(ns).rw_mutex); + up_write(&msg_ids(ns).rwsem); return err; } @@ -519,7 +500,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid, msginfo.msgmnb = ns->msg_ctlmnb; msginfo.msgssz = MSGSSZ; msginfo.msgseg = MSGSEG; - down_read(&msg_ids(ns).rw_mutex); + down_read(&msg_ids(ns).rwsem); if (cmd == MSG_INFO) { msginfo.msgpool = msg_ids(ns).in_use; msginfo.msgmap = atomic_read(&ns->msg_hdrs); @@ -530,7 +511,7 @@ static int msgctl_nolock(struct ipc_namespace *ns, int msqid, msginfo.msgtql = MSGTQL; } max_id = ipc_get_maxid(&msg_ids(ns)); - up_read(&msg_ids(ns).rw_mutex); + up_read(&msg_ids(ns).rwsem); if (copy_to_user(buf, &msginfo, sizeof(struct msginfo))) return -EFAULT; return (max_id < 0) ? 0 : max_id; @@ -705,16 +686,24 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, goto out_unlock1; } + ipc_lock_object(&msq->q_perm); + for (;;) { struct msg_sender s; err = -EACCES; if (ipcperms(ns, &msq->q_perm, S_IWUGO)) - goto out_unlock1; + goto out_unlock0; + + /* raced with RMID? */ + if (msq->q_perm.deleted) { + err = -EIDRM; + goto out_unlock0; + } err = security_msg_queue_msgsnd(msq, msg, msgflg); if (err) - goto out_unlock1; + goto out_unlock0; if (msgsz + msq->q_cbytes <= msq->q_qbytes && 1 + msq->q_qnum <= msq->q_qbytes) { @@ -724,10 +713,9 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, /* queue full, wait: */ if (msgflg & IPC_NOWAIT) { err = -EAGAIN; - goto out_unlock1; + goto out_unlock0; } - ipc_lock_object(&msq->q_perm); ss_add(msq, &s); if (!ipc_rcu_getref(msq)) { @@ -742,7 +730,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, rcu_read_lock(); ipc_lock_object(&msq->q_perm); - ipc_rcu_putref(msq); + ipc_rcu_putref(msq, ipc_rcu_free); if (msq->q_perm.deleted) { err = -EIDRM; goto out_unlock0; @@ -755,10 +743,7 @@ long do_msgsnd(int msqid, long mtype, void __user *mtext, goto out_unlock0; } - ipc_unlock_object(&msq->q_perm); } - - ipc_lock_object(&msq->q_perm); msq->q_lspid = task_tgid_vnr(current); msq->q_stime = get_seconds(); @@ -900,6 +885,8 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl return -EINVAL; if (msgflg & MSG_COPY) { + if ((msgflg & MSG_EXCEPT) || !(msgflg & IPC_NOWAIT)) + return -EINVAL; copy = prepare_copy(buf, min_t(size_t, bufsz, ns->msg_ctlmax)); if (IS_ERR(copy)) return PTR_ERR(copy); @@ -922,6 +909,13 @@ long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgfl goto out_unlock1; ipc_lock_object(&msq->q_perm); + + /* raced with RMID? */ + if (msq->q_perm.deleted) { + msg = ERR_PTR(-EIDRM); + goto out_unlock0; + } + msg = find_msg(msq, &msgtyp, mode); if (!IS_ERR(msg)) { /*