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- // SPDX-License-Identifier: GPL-2.0
- /*
- * linux/ipc/msg.c
- * Copyright (C) 1992 Krishna Balasubramanian
- *
- * Removed all the remaining kerneld mess
- * Catch the -EFAULT stuff properly
- * Use GFP_KERNEL for messages as in 1.2
- * Fixed up the unchecked user space derefs
- * Copyright (C) 1998 Alan Cox & Andi Kleen
- *
- * /proc/sysvipc/msg support (c) 1999 Dragos Acostachioaie <[email protected]>
- *
- * mostly rewritten, threaded and wake-one semantics added
- * MSGMAX limit removed, sysctl's added
- * (c) 1999 Manfred Spraul <[email protected]>
- *
- * support for audit of ipc object properties and permission changes
- * Dustin Kirkland <[email protected]>
- *
- * namespaces support
- * OpenVZ, SWsoft Inc.
- * Pavel Emelianov <[email protected]>
- */
- #include <linux/capability.h>
- #include <linux/msg.h>
- #include <linux/spinlock.h>
- #include <linux/init.h>
- #include <linux/mm.h>
- #include <linux/proc_fs.h>
- #include <linux/list.h>
- #include <linux/security.h>
- #include <linux/sched/wake_q.h>
- #include <linux/syscalls.h>
- #include <linux/audit.h>
- #include <linux/seq_file.h>
- #include <linux/rwsem.h>
- #include <linux/nsproxy.h>
- #include <linux/ipc_namespace.h>
- #include <linux/rhashtable.h>
- #include <linux/percpu_counter.h>
- #include <asm/current.h>
- #include <linux/uaccess.h>
- #include "util.h"
- /* one msq_queue structure for each present queue on the system */
- struct msg_queue {
- struct kern_ipc_perm q_perm;
- time64_t q_stime; /* last msgsnd time */
- time64_t q_rtime; /* last msgrcv time */
- time64_t q_ctime; /* last change time */
- unsigned long q_cbytes; /* current number of bytes on queue */
- unsigned long q_qnum; /* number of messages in queue */
- unsigned long q_qbytes; /* max number of bytes on queue */
- struct pid *q_lspid; /* pid of last msgsnd */
- struct pid *q_lrpid; /* last receive pid */
- struct list_head q_messages;
- struct list_head q_receivers;
- struct list_head q_senders;
- } __randomize_layout;
- /*
- * MSG_BARRIER Locking:
- *
- * Similar to the optimization used in ipc/mqueue.c, one syscall return path
- * does not acquire any locks when it sees that a message exists in
- * msg_receiver.r_msg. Therefore r_msg is set using smp_store_release()
- * and accessed using READ_ONCE()+smp_acquire__after_ctrl_dep(). In addition,
- * wake_q_add_safe() is used. See ipc/mqueue.c for more details
- */
- /* one msg_receiver structure for each sleeping receiver */
- struct msg_receiver {
- struct list_head r_list;
- struct task_struct *r_tsk;
- int r_mode;
- long r_msgtype;
- long r_maxsize;
- struct msg_msg *r_msg;
- };
- /* one msg_sender for each sleeping sender */
- struct msg_sender {
- struct list_head list;
- struct task_struct *tsk;
- size_t msgsz;
- };
- #define SEARCH_ANY 1
- #define SEARCH_EQUAL 2
- #define SEARCH_NOTEQUAL 3
- #define SEARCH_LESSEQUAL 4
- #define SEARCH_NUMBER 5
- #define msg_ids(ns) ((ns)->ids[IPC_MSG_IDS])
- static inline struct msg_queue *msq_obtain_object(struct ipc_namespace *ns, int id)
- {
- struct kern_ipc_perm *ipcp = ipc_obtain_object_idr(&msg_ids(ns), id);
- if (IS_ERR(ipcp))
- return ERR_CAST(ipcp);
- return container_of(ipcp, struct msg_queue, q_perm);
- }
- static inline struct msg_queue *msq_obtain_object_check(struct ipc_namespace *ns,
- int id)
- {
- struct kern_ipc_perm *ipcp = ipc_obtain_object_check(&msg_ids(ns), id);
- if (IS_ERR(ipcp))
- return ERR_CAST(ipcp);
- return container_of(ipcp, struct msg_queue, q_perm);
- }
- 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 kern_ipc_perm *p = container_of(head, struct kern_ipc_perm, rcu);
- struct msg_queue *msq = container_of(p, struct msg_queue, q_perm);
- security_msg_queue_free(&msq->q_perm);
- kfree(msq);
- }
- /**
- * newque - Create a new msg queue
- * @ns: namespace
- * @params: ptr to the structure that contains the key and msgflg
- *
- * Called with msg_ids.rwsem held (writer)
- */
- static int newque(struct ipc_namespace *ns, struct ipc_params *params)
- {
- struct msg_queue *msq;
- int retval;
- key_t key = params->key;
- int msgflg = params->flg;
- msq = kmalloc(sizeof(*msq), GFP_KERNEL_ACCOUNT);
- if (unlikely(!msq))
- return -ENOMEM;
- msq->q_perm.mode = msgflg & S_IRWXUGO;
- msq->q_perm.key = key;
- msq->q_perm.security = NULL;
- retval = security_msg_queue_alloc(&msq->q_perm);
- if (retval) {
- kfree(msq);
- return retval;
- }
- msq->q_stime = msq->q_rtime = 0;
- msq->q_ctime = ktime_get_real_seconds();
- msq->q_cbytes = msq->q_qnum = 0;
- msq->q_qbytes = ns->msg_ctlmnb;
- msq->q_lspid = msq->q_lrpid = NULL;
- INIT_LIST_HEAD(&msq->q_messages);
- INIT_LIST_HEAD(&msq->q_receivers);
- INIT_LIST_HEAD(&msq->q_senders);
- /* ipc_addid() locks msq upon success. */
- retval = ipc_addid(&msg_ids(ns), &msq->q_perm, ns->msg_ctlmni);
- if (retval < 0) {
- ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
- return retval;
- }
- ipc_unlock_object(&msq->q_perm);
- rcu_read_unlock();
- return msq->q_perm.id;
- }
- static inline bool msg_fits_inqueue(struct msg_queue *msq, size_t msgsz)
- {
- return msgsz + msq->q_cbytes <= msq->q_qbytes &&
- 1 + msq->q_qnum <= msq->q_qbytes;
- }
- static inline void ss_add(struct msg_queue *msq,
- struct msg_sender *mss, size_t msgsz)
- {
- mss->tsk = current;
- mss->msgsz = msgsz;
- /*
- * No memory barrier required: we did ipc_lock_object(),
- * and the waker obtains that lock before calling wake_q_add().
- */
- __set_current_state(TASK_INTERRUPTIBLE);
- list_add_tail(&mss->list, &msq->q_senders);
- }
- static inline void ss_del(struct msg_sender *mss)
- {
- if (mss->list.next)
- list_del(&mss->list);
- }
- static void ss_wakeup(struct msg_queue *msq,
- struct wake_q_head *wake_q, bool kill)
- {
- struct msg_sender *mss, *t;
- struct task_struct *stop_tsk = NULL;
- struct list_head *h = &msq->q_senders;
- list_for_each_entry_safe(mss, t, h, list) {
- if (kill)
- mss->list.next = NULL;
- /*
- * Stop at the first task we don't wakeup,
- * we've already iterated the original
- * sender queue.
- */
- else if (stop_tsk == mss->tsk)
- break;
- /*
- * We are not in an EIDRM scenario here, therefore
- * verify that we really need to wakeup the task.
- * To maintain current semantics and wakeup order,
- * move the sender to the tail on behalf of the
- * blocked task.
- */
- else if (!msg_fits_inqueue(msq, mss->msgsz)) {
- if (!stop_tsk)
- stop_tsk = mss->tsk;
- list_move_tail(&mss->list, &msq->q_senders);
- continue;
- }
- wake_q_add(wake_q, mss->tsk);
- }
- }
- static void expunge_all(struct msg_queue *msq, int res,
- struct wake_q_head *wake_q)
- {
- struct msg_receiver *msr, *t;
- list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
- struct task_struct *r_tsk;
- r_tsk = get_task_struct(msr->r_tsk);
- /* see MSG_BARRIER for purpose/pairing */
- smp_store_release(&msr->r_msg, ERR_PTR(res));
- wake_q_add_safe(wake_q, r_tsk);
- }
- }
- /*
- * 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.
- *
- * 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)
- __releases(RCU)
- __releases(&msq->q_perm)
- {
- struct msg_msg *msg, *t;
- struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
- DEFINE_WAKE_Q(wake_q);
- expunge_all(msq, -EIDRM, &wake_q);
- ss_wakeup(msq, &wake_q, true);
- msg_rmid(ns, msq);
- ipc_unlock_object(&msq->q_perm);
- wake_up_q(&wake_q);
- rcu_read_unlock();
- list_for_each_entry_safe(msg, t, &msq->q_messages, m_list) {
- percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
- free_msg(msg);
- }
- percpu_counter_sub_local(&ns->percpu_msg_bytes, msq->q_cbytes);
- ipc_update_pid(&msq->q_lspid, NULL);
- ipc_update_pid(&msq->q_lrpid, NULL);
- ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
- }
- long ksys_msgget(key_t key, int msgflg)
- {
- struct ipc_namespace *ns;
- static const struct ipc_ops msg_ops = {
- .getnew = newque,
- .associate = security_msg_queue_associate,
- };
- struct ipc_params msg_params;
- ns = current->nsproxy->ipc_ns;
- msg_params.key = key;
- msg_params.flg = msgflg;
- return ipcget(ns, &msg_ids(ns), &msg_ops, &msg_params);
- }
- SYSCALL_DEFINE2(msgget, key_t, key, int, msgflg)
- {
- return ksys_msgget(key, msgflg);
- }
- static inline unsigned long
- copy_msqid_to_user(void __user *buf, struct msqid64_ds *in, int version)
- {
- switch (version) {
- case IPC_64:
- return copy_to_user(buf, in, sizeof(*in));
- case IPC_OLD:
- {
- struct msqid_ds out;
- memset(&out, 0, sizeof(out));
- ipc64_perm_to_ipc_perm(&in->msg_perm, &out.msg_perm);
- out.msg_stime = in->msg_stime;
- out.msg_rtime = in->msg_rtime;
- out.msg_ctime = in->msg_ctime;
- if (in->msg_cbytes > USHRT_MAX)
- out.msg_cbytes = USHRT_MAX;
- else
- out.msg_cbytes = in->msg_cbytes;
- out.msg_lcbytes = in->msg_cbytes;
- if (in->msg_qnum > USHRT_MAX)
- out.msg_qnum = USHRT_MAX;
- else
- out.msg_qnum = in->msg_qnum;
- if (in->msg_qbytes > USHRT_MAX)
- out.msg_qbytes = USHRT_MAX;
- else
- out.msg_qbytes = in->msg_qbytes;
- out.msg_lqbytes = in->msg_qbytes;
- out.msg_lspid = in->msg_lspid;
- out.msg_lrpid = in->msg_lrpid;
- return copy_to_user(buf, &out, sizeof(out));
- }
- default:
- return -EINVAL;
- }
- }
- static inline unsigned long
- copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
- {
- switch (version) {
- case IPC_64:
- if (copy_from_user(out, buf, sizeof(*out)))
- return -EFAULT;
- return 0;
- case IPC_OLD:
- {
- struct msqid_ds tbuf_old;
- if (copy_from_user(&tbuf_old, buf, sizeof(tbuf_old)))
- return -EFAULT;
- out->msg_perm.uid = tbuf_old.msg_perm.uid;
- out->msg_perm.gid = tbuf_old.msg_perm.gid;
- out->msg_perm.mode = tbuf_old.msg_perm.mode;
- if (tbuf_old.msg_qbytes == 0)
- out->msg_qbytes = tbuf_old.msg_lqbytes;
- else
- out->msg_qbytes = tbuf_old.msg_qbytes;
- return 0;
- }
- default:
- return -EINVAL;
- }
- }
- /*
- * This function handles some msgctl commands which require the rwsem
- * to be held in write mode.
- * 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 ipc64_perm *perm, int msg_qbytes)
- {
- struct kern_ipc_perm *ipcp;
- struct msg_queue *msq;
- int err;
- down_write(&msg_ids(ns).rwsem);
- rcu_read_lock();
- ipcp = ipcctl_obtain_check(ns, &msg_ids(ns), msqid, cmd,
- perm, msg_qbytes);
- if (IS_ERR(ipcp)) {
- err = PTR_ERR(ipcp);
- goto out_unlock1;
- }
- msq = container_of(ipcp, struct msg_queue, q_perm);
- err = security_msg_queue_msgctl(&msq->q_perm, cmd);
- if (err)
- goto out_unlock1;
- switch (cmd) {
- case IPC_RMID:
- ipc_lock_object(&msq->q_perm);
- /* freeque unlocks the ipc object and rcu */
- freeque(ns, ipcp);
- goto out_up;
- case IPC_SET:
- {
- DEFINE_WAKE_Q(wake_q);
- if (msg_qbytes > ns->msg_ctlmnb &&
- !capable(CAP_SYS_RESOURCE)) {
- err = -EPERM;
- goto out_unlock1;
- }
- ipc_lock_object(&msq->q_perm);
- err = ipc_update_perm(perm, ipcp);
- if (err)
- goto out_unlock0;
- msq->q_qbytes = msg_qbytes;
- msq->q_ctime = ktime_get_real_seconds();
- /*
- * Sleeping receivers might be excluded by
- * stricter permissions.
- */
- expunge_all(msq, -EAGAIN, &wake_q);
- /*
- * Sleeping senders might be able to send
- * due to a larger queue size.
- */
- ss_wakeup(msq, &wake_q, false);
- ipc_unlock_object(&msq->q_perm);
- wake_up_q(&wake_q);
- goto out_unlock1;
- }
- default:
- err = -EINVAL;
- goto out_unlock1;
- }
- out_unlock0:
- ipc_unlock_object(&msq->q_perm);
- out_unlock1:
- rcu_read_unlock();
- out_up:
- up_write(&msg_ids(ns).rwsem);
- return err;
- }
- static int msgctl_info(struct ipc_namespace *ns, int msqid,
- int cmd, struct msginfo *msginfo)
- {
- int err;
- int max_idx;
- /*
- * We must not return kernel stack data.
- * due to padding, it's not enough
- * to set all member fields.
- */
- err = security_msg_queue_msgctl(NULL, cmd);
- if (err)
- return err;
- memset(msginfo, 0, sizeof(*msginfo));
- msginfo->msgmni = ns->msg_ctlmni;
- msginfo->msgmax = ns->msg_ctlmax;
- msginfo->msgmnb = ns->msg_ctlmnb;
- msginfo->msgssz = MSGSSZ;
- msginfo->msgseg = MSGSEG;
- down_read(&msg_ids(ns).rwsem);
- if (cmd == MSG_INFO)
- msginfo->msgpool = msg_ids(ns).in_use;
- max_idx = ipc_get_maxidx(&msg_ids(ns));
- up_read(&msg_ids(ns).rwsem);
- if (cmd == MSG_INFO) {
- msginfo->msgmap = min_t(int,
- percpu_counter_sum(&ns->percpu_msg_hdrs),
- INT_MAX);
- msginfo->msgtql = min_t(int,
- percpu_counter_sum(&ns->percpu_msg_bytes),
- INT_MAX);
- } else {
- msginfo->msgmap = MSGMAP;
- msginfo->msgpool = MSGPOOL;
- msginfo->msgtql = MSGTQL;
- }
- return (max_idx < 0) ? 0 : max_idx;
- }
- static int msgctl_stat(struct ipc_namespace *ns, int msqid,
- int cmd, struct msqid64_ds *p)
- {
- struct msg_queue *msq;
- int err;
- memset(p, 0, sizeof(*p));
- rcu_read_lock();
- if (cmd == MSG_STAT || cmd == MSG_STAT_ANY) {
- msq = msq_obtain_object(ns, msqid);
- if (IS_ERR(msq)) {
- err = PTR_ERR(msq);
- goto out_unlock;
- }
- } else { /* IPC_STAT */
- msq = msq_obtain_object_check(ns, msqid);
- if (IS_ERR(msq)) {
- err = PTR_ERR(msq);
- goto out_unlock;
- }
- }
- /* see comment for SHM_STAT_ANY */
- if (cmd == MSG_STAT_ANY)
- audit_ipc_obj(&msq->q_perm);
- else {
- err = -EACCES;
- if (ipcperms(ns, &msq->q_perm, S_IRUGO))
- goto out_unlock;
- }
- err = security_msg_queue_msgctl(&msq->q_perm, cmd);
- if (err)
- goto out_unlock;
- ipc_lock_object(&msq->q_perm);
- if (!ipc_valid_object(&msq->q_perm)) {
- ipc_unlock_object(&msq->q_perm);
- err = -EIDRM;
- goto out_unlock;
- }
- kernel_to_ipc64_perm(&msq->q_perm, &p->msg_perm);
- p->msg_stime = msq->q_stime;
- p->msg_rtime = msq->q_rtime;
- p->msg_ctime = msq->q_ctime;
- #ifndef CONFIG_64BIT
- p->msg_stime_high = msq->q_stime >> 32;
- p->msg_rtime_high = msq->q_rtime >> 32;
- p->msg_ctime_high = msq->q_ctime >> 32;
- #endif
- p->msg_cbytes = msq->q_cbytes;
- p->msg_qnum = msq->q_qnum;
- p->msg_qbytes = msq->q_qbytes;
- p->msg_lspid = pid_vnr(msq->q_lspid);
- p->msg_lrpid = pid_vnr(msq->q_lrpid);
- if (cmd == IPC_STAT) {
- /*
- * As defined in SUS:
- * Return 0 on success
- */
- err = 0;
- } else {
- /*
- * MSG_STAT and MSG_STAT_ANY (both Linux specific)
- * Return the full id, including the sequence number
- */
- err = msq->q_perm.id;
- }
- ipc_unlock_object(&msq->q_perm);
- out_unlock:
- rcu_read_unlock();
- return err;
- }
- static long ksys_msgctl(int msqid, int cmd, struct msqid_ds __user *buf, int version)
- {
- struct ipc_namespace *ns;
- struct msqid64_ds msqid64;
- int err;
- if (msqid < 0 || cmd < 0)
- return -EINVAL;
- ns = current->nsproxy->ipc_ns;
- switch (cmd) {
- case IPC_INFO:
- case MSG_INFO: {
- struct msginfo msginfo;
- err = msgctl_info(ns, msqid, cmd, &msginfo);
- if (err < 0)
- return err;
- if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
- err = -EFAULT;
- return err;
- }
- case MSG_STAT: /* msqid is an index rather than a msg queue id */
- case MSG_STAT_ANY:
- case IPC_STAT:
- err = msgctl_stat(ns, msqid, cmd, &msqid64);
- if (err < 0)
- return err;
- if (copy_msqid_to_user(buf, &msqid64, version))
- err = -EFAULT;
- return err;
- case IPC_SET:
- if (copy_msqid_from_user(&msqid64, buf, version))
- return -EFAULT;
- return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm,
- msqid64.msg_qbytes);
- case IPC_RMID:
- return msgctl_down(ns, msqid, cmd, NULL, 0);
- default:
- return -EINVAL;
- }
- }
- SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
- {
- return ksys_msgctl(msqid, cmd, buf, IPC_64);
- }
- #ifdef CONFIG_ARCH_WANT_IPC_PARSE_VERSION
- long ksys_old_msgctl(int msqid, int cmd, struct msqid_ds __user *buf)
- {
- int version = ipc_parse_version(&cmd);
- return ksys_msgctl(msqid, cmd, buf, version);
- }
- SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
- {
- return ksys_old_msgctl(msqid, cmd, buf);
- }
- #endif
- #ifdef CONFIG_COMPAT
- struct compat_msqid_ds {
- struct compat_ipc_perm msg_perm;
- compat_uptr_t msg_first;
- compat_uptr_t msg_last;
- old_time32_t msg_stime;
- old_time32_t msg_rtime;
- old_time32_t msg_ctime;
- compat_ulong_t msg_lcbytes;
- compat_ulong_t msg_lqbytes;
- unsigned short msg_cbytes;
- unsigned short msg_qnum;
- unsigned short msg_qbytes;
- compat_ipc_pid_t msg_lspid;
- compat_ipc_pid_t msg_lrpid;
- };
- static int copy_compat_msqid_from_user(struct msqid64_ds *out, void __user *buf,
- int version)
- {
- memset(out, 0, sizeof(*out));
- if (version == IPC_64) {
- struct compat_msqid64_ds __user *p = buf;
- if (get_compat_ipc64_perm(&out->msg_perm, &p->msg_perm))
- return -EFAULT;
- if (get_user(out->msg_qbytes, &p->msg_qbytes))
- return -EFAULT;
- } else {
- struct compat_msqid_ds __user *p = buf;
- if (get_compat_ipc_perm(&out->msg_perm, &p->msg_perm))
- return -EFAULT;
- if (get_user(out->msg_qbytes, &p->msg_qbytes))
- return -EFAULT;
- }
- return 0;
- }
- static int copy_compat_msqid_to_user(void __user *buf, struct msqid64_ds *in,
- int version)
- {
- if (version == IPC_64) {
- struct compat_msqid64_ds v;
- memset(&v, 0, sizeof(v));
- to_compat_ipc64_perm(&v.msg_perm, &in->msg_perm);
- v.msg_stime = lower_32_bits(in->msg_stime);
- v.msg_stime_high = upper_32_bits(in->msg_stime);
- v.msg_rtime = lower_32_bits(in->msg_rtime);
- v.msg_rtime_high = upper_32_bits(in->msg_rtime);
- v.msg_ctime = lower_32_bits(in->msg_ctime);
- v.msg_ctime_high = upper_32_bits(in->msg_ctime);
- v.msg_cbytes = in->msg_cbytes;
- v.msg_qnum = in->msg_qnum;
- v.msg_qbytes = in->msg_qbytes;
- v.msg_lspid = in->msg_lspid;
- v.msg_lrpid = in->msg_lrpid;
- return copy_to_user(buf, &v, sizeof(v));
- } else {
- struct compat_msqid_ds v;
- memset(&v, 0, sizeof(v));
- to_compat_ipc_perm(&v.msg_perm, &in->msg_perm);
- v.msg_stime = in->msg_stime;
- v.msg_rtime = in->msg_rtime;
- v.msg_ctime = in->msg_ctime;
- v.msg_cbytes = in->msg_cbytes;
- v.msg_qnum = in->msg_qnum;
- v.msg_qbytes = in->msg_qbytes;
- v.msg_lspid = in->msg_lspid;
- v.msg_lrpid = in->msg_lrpid;
- return copy_to_user(buf, &v, sizeof(v));
- }
- }
- static long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr, int version)
- {
- struct ipc_namespace *ns;
- int err;
- struct msqid64_ds msqid64;
- ns = current->nsproxy->ipc_ns;
- if (msqid < 0 || cmd < 0)
- return -EINVAL;
- switch (cmd & (~IPC_64)) {
- case IPC_INFO:
- case MSG_INFO: {
- struct msginfo msginfo;
- err = msgctl_info(ns, msqid, cmd, &msginfo);
- if (err < 0)
- return err;
- if (copy_to_user(uptr, &msginfo, sizeof(struct msginfo)))
- err = -EFAULT;
- return err;
- }
- case IPC_STAT:
- case MSG_STAT:
- case MSG_STAT_ANY:
- err = msgctl_stat(ns, msqid, cmd, &msqid64);
- if (err < 0)
- return err;
- if (copy_compat_msqid_to_user(uptr, &msqid64, version))
- err = -EFAULT;
- return err;
- case IPC_SET:
- if (copy_compat_msqid_from_user(&msqid64, uptr, version))
- return -EFAULT;
- return msgctl_down(ns, msqid, cmd, &msqid64.msg_perm, msqid64.msg_qbytes);
- case IPC_RMID:
- return msgctl_down(ns, msqid, cmd, NULL, 0);
- default:
- return -EINVAL;
- }
- }
- COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
- {
- return compat_ksys_msgctl(msqid, cmd, uptr, IPC_64);
- }
- #ifdef CONFIG_ARCH_WANT_COMPAT_IPC_PARSE_VERSION
- long compat_ksys_old_msgctl(int msqid, int cmd, void __user *uptr)
- {
- int version = compat_ipc_parse_version(&cmd);
- return compat_ksys_msgctl(msqid, cmd, uptr, version);
- }
- COMPAT_SYSCALL_DEFINE3(old_msgctl, int, msqid, int, cmd, void __user *, uptr)
- {
- return compat_ksys_old_msgctl(msqid, cmd, uptr);
- }
- #endif
- #endif
- static int testmsg(struct msg_msg *msg, long type, int mode)
- {
- switch (mode) {
- case SEARCH_ANY:
- case SEARCH_NUMBER:
- return 1;
- case SEARCH_LESSEQUAL:
- if (msg->m_type <= type)
- return 1;
- break;
- case SEARCH_EQUAL:
- if (msg->m_type == type)
- return 1;
- break;
- case SEARCH_NOTEQUAL:
- if (msg->m_type != type)
- return 1;
- break;
- }
- return 0;
- }
- static inline int pipelined_send(struct msg_queue *msq, struct msg_msg *msg,
- struct wake_q_head *wake_q)
- {
- struct msg_receiver *msr, *t;
- list_for_each_entry_safe(msr, t, &msq->q_receivers, r_list) {
- if (testmsg(msg, msr->r_msgtype, msr->r_mode) &&
- !security_msg_queue_msgrcv(&msq->q_perm, msg, msr->r_tsk,
- msr->r_msgtype, msr->r_mode)) {
- list_del(&msr->r_list);
- if (msr->r_maxsize < msg->m_ts) {
- wake_q_add(wake_q, msr->r_tsk);
- /* See expunge_all regarding memory barrier */
- smp_store_release(&msr->r_msg, ERR_PTR(-E2BIG));
- } else {
- ipc_update_pid(&msq->q_lrpid, task_pid(msr->r_tsk));
- msq->q_rtime = ktime_get_real_seconds();
- wake_q_add(wake_q, msr->r_tsk);
- /* See expunge_all regarding memory barrier */
- smp_store_release(&msr->r_msg, msg);
- return 1;
- }
- }
- }
- return 0;
- }
- static long do_msgsnd(int msqid, long mtype, void __user *mtext,
- size_t msgsz, int msgflg)
- {
- struct msg_queue *msq;
- struct msg_msg *msg;
- int err;
- struct ipc_namespace *ns;
- DEFINE_WAKE_Q(wake_q);
- ns = current->nsproxy->ipc_ns;
- if (msgsz > ns->msg_ctlmax || (long) msgsz < 0 || msqid < 0)
- return -EINVAL;
- if (mtype < 1)
- return -EINVAL;
- msg = load_msg(mtext, msgsz);
- if (IS_ERR(msg))
- return PTR_ERR(msg);
- msg->m_type = mtype;
- msg->m_ts = msgsz;
- rcu_read_lock();
- msq = msq_obtain_object_check(ns, msqid);
- if (IS_ERR(msq)) {
- err = PTR_ERR(msq);
- 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_unlock0;
- /* raced with RMID? */
- if (!ipc_valid_object(&msq->q_perm)) {
- err = -EIDRM;
- goto out_unlock0;
- }
- err = security_msg_queue_msgsnd(&msq->q_perm, msg, msgflg);
- if (err)
- goto out_unlock0;
- if (msg_fits_inqueue(msq, msgsz))
- break;
- /* queue full, wait: */
- if (msgflg & IPC_NOWAIT) {
- err = -EAGAIN;
- goto out_unlock0;
- }
- /* enqueue the sender and prepare to block */
- ss_add(msq, &s, msgsz);
- if (!ipc_rcu_getref(&msq->q_perm)) {
- err = -EIDRM;
- goto out_unlock0;
- }
- ipc_unlock_object(&msq->q_perm);
- rcu_read_unlock();
- schedule();
- rcu_read_lock();
- ipc_lock_object(&msq->q_perm);
- ipc_rcu_putref(&msq->q_perm, msg_rcu_free);
- /* raced with RMID? */
- if (!ipc_valid_object(&msq->q_perm)) {
- err = -EIDRM;
- goto out_unlock0;
- }
- ss_del(&s);
- if (signal_pending(current)) {
- err = -ERESTARTNOHAND;
- goto out_unlock0;
- }
- }
- ipc_update_pid(&msq->q_lspid, task_tgid(current));
- msq->q_stime = ktime_get_real_seconds();
- if (!pipelined_send(msq, msg, &wake_q)) {
- /* no one is waiting for this message, enqueue it */
- list_add_tail(&msg->m_list, &msq->q_messages);
- msq->q_cbytes += msgsz;
- msq->q_qnum++;
- percpu_counter_add_local(&ns->percpu_msg_bytes, msgsz);
- percpu_counter_add_local(&ns->percpu_msg_hdrs, 1);
- }
- err = 0;
- msg = NULL;
- out_unlock0:
- ipc_unlock_object(&msq->q_perm);
- wake_up_q(&wake_q);
- out_unlock1:
- rcu_read_unlock();
- if (msg != NULL)
- free_msg(msg);
- return err;
- }
- long ksys_msgsnd(int msqid, struct msgbuf __user *msgp, size_t msgsz,
- int msgflg)
- {
- long mtype;
- if (get_user(mtype, &msgp->mtype))
- return -EFAULT;
- return do_msgsnd(msqid, mtype, msgp->mtext, msgsz, msgflg);
- }
- SYSCALL_DEFINE4(msgsnd, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
- int, msgflg)
- {
- return ksys_msgsnd(msqid, msgp, msgsz, msgflg);
- }
- #ifdef CONFIG_COMPAT
- struct compat_msgbuf {
- compat_long_t mtype;
- char mtext[1];
- };
- long compat_ksys_msgsnd(int msqid, compat_uptr_t msgp,
- compat_ssize_t msgsz, int msgflg)
- {
- struct compat_msgbuf __user *up = compat_ptr(msgp);
- compat_long_t mtype;
- if (get_user(mtype, &up->mtype))
- return -EFAULT;
- return do_msgsnd(msqid, mtype, up->mtext, (ssize_t)msgsz, msgflg);
- }
- COMPAT_SYSCALL_DEFINE4(msgsnd, int, msqid, compat_uptr_t, msgp,
- compat_ssize_t, msgsz, int, msgflg)
- {
- return compat_ksys_msgsnd(msqid, msgp, msgsz, msgflg);
- }
- #endif
- static inline int convert_mode(long *msgtyp, int msgflg)
- {
- if (msgflg & MSG_COPY)
- return SEARCH_NUMBER;
- /*
- * find message of correct type.
- * msgtyp = 0 => get first.
- * msgtyp > 0 => get first message of matching type.
- * msgtyp < 0 => get message with least type must be < abs(msgtype).
- */
- if (*msgtyp == 0)
- return SEARCH_ANY;
- if (*msgtyp < 0) {
- if (*msgtyp == LONG_MIN) /* -LONG_MIN is undefined */
- *msgtyp = LONG_MAX;
- else
- *msgtyp = -*msgtyp;
- return SEARCH_LESSEQUAL;
- }
- if (msgflg & MSG_EXCEPT)
- return SEARCH_NOTEQUAL;
- return SEARCH_EQUAL;
- }
- static long do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
- {
- struct msgbuf __user *msgp = dest;
- size_t msgsz;
- if (put_user(msg->m_type, &msgp->mtype))
- return -EFAULT;
- msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
- if (store_msg(msgp->mtext, msg, msgsz))
- return -EFAULT;
- return msgsz;
- }
- #ifdef CONFIG_CHECKPOINT_RESTORE
- /*
- * This function creates new kernel message structure, large enough to store
- * bufsz message bytes.
- */
- static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
- {
- struct msg_msg *copy;
- /*
- * Create dummy message to copy real message to.
- */
- copy = load_msg(buf, bufsz);
- if (!IS_ERR(copy))
- copy->m_ts = bufsz;
- return copy;
- }
- static inline void free_copy(struct msg_msg *copy)
- {
- if (copy)
- free_msg(copy);
- }
- #else
- static inline struct msg_msg *prepare_copy(void __user *buf, size_t bufsz)
- {
- return ERR_PTR(-ENOSYS);
- }
- static inline void free_copy(struct msg_msg *copy)
- {
- }
- #endif
- static struct msg_msg *find_msg(struct msg_queue *msq, long *msgtyp, int mode)
- {
- struct msg_msg *msg, *found = NULL;
- long count = 0;
- list_for_each_entry(msg, &msq->q_messages, m_list) {
- if (testmsg(msg, *msgtyp, mode) &&
- !security_msg_queue_msgrcv(&msq->q_perm, msg, current,
- *msgtyp, mode)) {
- if (mode == SEARCH_LESSEQUAL && msg->m_type != 1) {
- *msgtyp = msg->m_type - 1;
- found = msg;
- } else if (mode == SEARCH_NUMBER) {
- if (*msgtyp == count)
- return msg;
- } else
- return msg;
- count++;
- }
- }
- return found ?: ERR_PTR(-EAGAIN);
- }
- static long do_msgrcv(int msqid, void __user *buf, size_t bufsz, long msgtyp, int msgflg,
- long (*msg_handler)(void __user *, struct msg_msg *, size_t))
- {
- int mode;
- struct msg_queue *msq;
- struct ipc_namespace *ns;
- struct msg_msg *msg, *copy = NULL;
- DEFINE_WAKE_Q(wake_q);
- ns = current->nsproxy->ipc_ns;
- if (msqid < 0 || (long) bufsz < 0)
- 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);
- }
- mode = convert_mode(&msgtyp, msgflg);
- rcu_read_lock();
- msq = msq_obtain_object_check(ns, msqid);
- if (IS_ERR(msq)) {
- rcu_read_unlock();
- free_copy(copy);
- return PTR_ERR(msq);
- }
- for (;;) {
- struct msg_receiver msr_d;
- msg = ERR_PTR(-EACCES);
- if (ipcperms(ns, &msq->q_perm, S_IRUGO))
- goto out_unlock1;
- ipc_lock_object(&msq->q_perm);
- /* raced with RMID? */
- if (!ipc_valid_object(&msq->q_perm)) {
- msg = ERR_PTR(-EIDRM);
- goto out_unlock0;
- }
- msg = find_msg(msq, &msgtyp, mode);
- if (!IS_ERR(msg)) {
- /*
- * Found a suitable message.
- * Unlink it from the queue.
- */
- if ((bufsz < msg->m_ts) && !(msgflg & MSG_NOERROR)) {
- msg = ERR_PTR(-E2BIG);
- goto out_unlock0;
- }
- /*
- * If we are copying, then do not unlink message and do
- * not update queue parameters.
- */
- if (msgflg & MSG_COPY) {
- msg = copy_msg(msg, copy);
- goto out_unlock0;
- }
- list_del(&msg->m_list);
- msq->q_qnum--;
- msq->q_rtime = ktime_get_real_seconds();
- ipc_update_pid(&msq->q_lrpid, task_tgid(current));
- msq->q_cbytes -= msg->m_ts;
- percpu_counter_sub_local(&ns->percpu_msg_bytes, msg->m_ts);
- percpu_counter_sub_local(&ns->percpu_msg_hdrs, 1);
- ss_wakeup(msq, &wake_q, false);
- goto out_unlock0;
- }
- /* No message waiting. Wait for a message */
- if (msgflg & IPC_NOWAIT) {
- msg = ERR_PTR(-ENOMSG);
- goto out_unlock0;
- }
- list_add_tail(&msr_d.r_list, &msq->q_receivers);
- msr_d.r_tsk = current;
- msr_d.r_msgtype = msgtyp;
- msr_d.r_mode = mode;
- if (msgflg & MSG_NOERROR)
- msr_d.r_maxsize = INT_MAX;
- else
- msr_d.r_maxsize = bufsz;
- /* memory barrier not require due to ipc_lock_object() */
- WRITE_ONCE(msr_d.r_msg, ERR_PTR(-EAGAIN));
- /* memory barrier not required, we own ipc_lock_object() */
- __set_current_state(TASK_INTERRUPTIBLE);
- ipc_unlock_object(&msq->q_perm);
- rcu_read_unlock();
- schedule();
- /*
- * Lockless receive, part 1:
- * We don't hold a reference to the queue and getting a
- * reference would defeat the idea of a lockless operation,
- * thus the code relies on rcu to guarantee the existence of
- * msq:
- * Prior to destruction, expunge_all(-EIRDM) changes r_msg.
- * Thus if r_msg is -EAGAIN, then the queue not yet destroyed.
- */
- rcu_read_lock();
- /*
- * Lockless receive, part 2:
- * The work in pipelined_send() and expunge_all():
- * - Set pointer to message
- * - Queue the receiver task for later wakeup
- * - Wake up the process after the lock is dropped.
- *
- * Should the process wake up before this wakeup (due to a
- * signal) it will either see the message and continue ...
- */
- msg = READ_ONCE(msr_d.r_msg);
- if (msg != ERR_PTR(-EAGAIN)) {
- /* see MSG_BARRIER for purpose/pairing */
- smp_acquire__after_ctrl_dep();
- goto out_unlock1;
- }
- /*
- * ... or see -EAGAIN, acquire the lock to check the message
- * again.
- */
- ipc_lock_object(&msq->q_perm);
- msg = READ_ONCE(msr_d.r_msg);
- if (msg != ERR_PTR(-EAGAIN))
- goto out_unlock0;
- list_del(&msr_d.r_list);
- if (signal_pending(current)) {
- msg = ERR_PTR(-ERESTARTNOHAND);
- goto out_unlock0;
- }
- ipc_unlock_object(&msq->q_perm);
- }
- out_unlock0:
- ipc_unlock_object(&msq->q_perm);
- wake_up_q(&wake_q);
- out_unlock1:
- rcu_read_unlock();
- if (IS_ERR(msg)) {
- free_copy(copy);
- return PTR_ERR(msg);
- }
- bufsz = msg_handler(buf, msg, bufsz);
- free_msg(msg);
- return bufsz;
- }
- long ksys_msgrcv(int msqid, struct msgbuf __user *msgp, size_t msgsz,
- long msgtyp, int msgflg)
- {
- return do_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg, do_msg_fill);
- }
- SYSCALL_DEFINE5(msgrcv, int, msqid, struct msgbuf __user *, msgp, size_t, msgsz,
- long, msgtyp, int, msgflg)
- {
- return ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
- }
- #ifdef CONFIG_COMPAT
- static long compat_do_msg_fill(void __user *dest, struct msg_msg *msg, size_t bufsz)
- {
- struct compat_msgbuf __user *msgp = dest;
- size_t msgsz;
- if (put_user(msg->m_type, &msgp->mtype))
- return -EFAULT;
- msgsz = (bufsz > msg->m_ts) ? msg->m_ts : bufsz;
- if (store_msg(msgp->mtext, msg, msgsz))
- return -EFAULT;
- return msgsz;
- }
- long compat_ksys_msgrcv(int msqid, compat_uptr_t msgp, compat_ssize_t msgsz,
- compat_long_t msgtyp, int msgflg)
- {
- return do_msgrcv(msqid, compat_ptr(msgp), (ssize_t)msgsz, (long)msgtyp,
- msgflg, compat_do_msg_fill);
- }
- COMPAT_SYSCALL_DEFINE5(msgrcv, int, msqid, compat_uptr_t, msgp,
- compat_ssize_t, msgsz, compat_long_t, msgtyp,
- int, msgflg)
- {
- return compat_ksys_msgrcv(msqid, msgp, msgsz, msgtyp, msgflg);
- }
- #endif
- int msg_init_ns(struct ipc_namespace *ns)
- {
- int ret;
- ns->msg_ctlmax = MSGMAX;
- ns->msg_ctlmnb = MSGMNB;
- ns->msg_ctlmni = MSGMNI;
- ret = percpu_counter_init(&ns->percpu_msg_bytes, 0, GFP_KERNEL);
- if (ret)
- goto fail_msg_bytes;
- ret = percpu_counter_init(&ns->percpu_msg_hdrs, 0, GFP_KERNEL);
- if (ret)
- goto fail_msg_hdrs;
- ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
- return 0;
- fail_msg_hdrs:
- percpu_counter_destroy(&ns->percpu_msg_bytes);
- fail_msg_bytes:
- return ret;
- }
- #ifdef CONFIG_IPC_NS
- void msg_exit_ns(struct ipc_namespace *ns)
- {
- free_ipcs(ns, &msg_ids(ns), freeque);
- idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
- rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
- percpu_counter_destroy(&ns->percpu_msg_bytes);
- percpu_counter_destroy(&ns->percpu_msg_hdrs);
- }
- #endif
- #ifdef CONFIG_PROC_FS
- static int sysvipc_msg_proc_show(struct seq_file *s, void *it)
- {
- struct pid_namespace *pid_ns = ipc_seq_pid_ns(s);
- struct user_namespace *user_ns = seq_user_ns(s);
- struct kern_ipc_perm *ipcp = it;
- struct msg_queue *msq = container_of(ipcp, struct msg_queue, q_perm);
- seq_printf(s,
- "%10d %10d %4o %10lu %10lu %5u %5u %5u %5u %5u %5u %10llu %10llu %10llu\n",
- msq->q_perm.key,
- msq->q_perm.id,
- msq->q_perm.mode,
- msq->q_cbytes,
- msq->q_qnum,
- pid_nr_ns(msq->q_lspid, pid_ns),
- pid_nr_ns(msq->q_lrpid, pid_ns),
- from_kuid_munged(user_ns, msq->q_perm.uid),
- from_kgid_munged(user_ns, msq->q_perm.gid),
- from_kuid_munged(user_ns, msq->q_perm.cuid),
- from_kgid_munged(user_ns, msq->q_perm.cgid),
- msq->q_stime,
- msq->q_rtime,
- msq->q_ctime);
- return 0;
- }
- #endif
- void __init msg_init(void)
- {
- msg_init_ns(&init_ipc_ns);
- ipc_init_proc_interface("sysvipc/msg",
- " key msqid perms cbytes qnum lspid lrpid uid gid cuid cgid stime rtime ctime\n",
- IPC_MSG_IDS, sysvipc_msg_proc_show);
- }
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