Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1376 insertions, 0 deletions

diff --git a/ipc/msg.c b/ipc/msg.c
new file mode 100644
index 000000000..fd08b3cb3
--- /dev/null
+++ b/ipc/msg.c
@@ -0,0 +1,1376 @@
+// 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 <dragos@iname.com>
+ *
+ * mostly rewritten, threaded and wake-one semantics added
+ * MSGMAX limit removed, sysctl's added
+ * (c) 1999 Manfred Spraul <manfred@colorfullife.com>
+ *
+ * support for audit of ipc object properties and permission changes
+ * Dustin Kirkland <dustin.kirkland@us.ibm.com>
+ *
+ * namespaces support
+ * OpenVZ, SWsoft Inc.
+ * Pavel Emelianov <xemul@openvz.org>
+ */
+
+#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);
+}