v4.19.13 snapshot.
diff --git a/ipc/msg.c b/ipc/msg.c
new file mode 100644
index 0000000..883642c
--- /dev/null
+++ b/ipc/msg.c
@@ -0,0 +1,1297 @@
+// 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 <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;
+
+/* 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);
+ kvfree(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 = kvmalloc(sizeof(*msq), GFP_KERNEL);
+ 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) {
+ kvfree(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;
+ __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) {
+ wake_q_add(wake_q, msr->r_tsk);
+ WRITE_ONCE(msr->r_msg, ERR_PTR(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.
+ *
+ * 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)
+{
+ 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) {
+ atomic_dec(&ns->msg_hdrs);
+ free_msg(msg);
+ }
+ atomic_sub(msq->q_cbytes, &ns->msg_bytes);
+ 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 msqid64_ds *msqid64)
+{
+ 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,
+ &msqid64->msg_perm, msqid64->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 (msqid64->msg_qbytes > ns->msg_ctlmnb &&
+ !capable(CAP_SYS_RESOURCE)) {
+ err = -EPERM;
+ goto out_unlock1;
+ }
+
+ ipc_lock_object(&msq->q_perm);
+ err = ipc_update_perm(&msqid64->msg_perm, ipcp);
+ if (err)
+ goto out_unlock0;
+
+ msq->q_qbytes = msqid64->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;
+ msginfo->msgmap = atomic_read(&ns->msg_hdrs);
+ msginfo->msgtql = atomic_read(&ns->msg_bytes);
+ } else {
+ msginfo->msgmap = MSGMAP;
+ msginfo->msgpool = MSGPOOL;
+ msginfo->msgtql = MSGTQL;
+ }
+ max_idx = ipc_get_maxidx(&msg_ids(ns));
+ up_read(&msg_ids(ns).rwsem);
+ 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;
+}
+
+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;
+
+ version = ipc_parse_version(&cmd);
+ 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;
+ /* fallthru */
+ case IPC_RMID:
+ return msgctl_down(ns, msqid, cmd, &msqid64);
+ default:
+ return -EINVAL;
+ }
+}
+
+SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
+{
+ return ksys_msgctl(msqid, cmd, buf);
+}
+
+#ifdef CONFIG_COMPAT
+
+struct compat_msqid_ds {
+ struct compat_ipc_perm msg_perm;
+ compat_uptr_t msg_first;
+ compat_uptr_t msg_last;
+ compat_time_t msg_stime;
+ compat_time_t msg_rtime;
+ compat_time_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));
+ }
+}
+
+long compat_ksys_msgctl(int msqid, int cmd, void __user *uptr)
+{
+ struct ipc_namespace *ns;
+ int err;
+ struct msqid64_ds msqid64;
+ int version = compat_ipc_parse_version(&cmd);
+
+ 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;
+ /* fallthru */
+ case IPC_RMID:
+ return msgctl_down(ns, msqid, cmd, &msqid64);
+ default:
+ return -EINVAL;
+ }
+}
+
+COMPAT_SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, void __user *, uptr)
+{
+ return compat_ksys_msgctl(msqid, cmd, uptr);
+}
+#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);
+ WRITE_ONCE(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);
+ WRITE_ONCE(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++;
+ atomic_add(msgsz, &ns->msg_bytes);
+ atomic_inc(&ns->msg_hdrs);
+ }
+
+ 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;
+ atomic_sub(msg->m_ts, &ns->msg_bytes);
+ atomic_dec(&ns->msg_hdrs);
+ 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;
+ msr_d.r_msg = ERR_PTR(-EAGAIN);
+ __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))
+ goto out_unlock1;
+
+ /*
+ * ... or see -EAGAIN, acquire the lock to check the message
+ * again.
+ */
+ ipc_lock_object(&msq->q_perm);
+
+ msg = 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
+
+void msg_init_ns(struct ipc_namespace *ns)
+{
+ ns->msg_ctlmax = MSGMAX;
+ ns->msg_ctlmnb = MSGMNB;
+ ns->msg_ctlmni = MSGMNI;
+
+ atomic_set(&ns->msg_bytes, 0);
+ atomic_set(&ns->msg_hdrs, 0);
+ ipc_init_ids(&ns->ids[IPC_MSG_IDS]);
+}
+
+#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);
+}
+#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);
+}