diff options
Diffstat (limited to 'ipc/msg.c')
| -rw-r--r-- | ipc/msg.c | 1356 |
1 files changed, 1356 insertions, 0 deletions
diff --git a/ipc/msg.c b/ipc/msg.c new file mode 100644 index 000000000..8ded6b8f1 --- /dev/null +++ b/ipc/msg.c @@ -0,0 +1,1356 @@ +// 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; + +/* + * 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); + 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_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) { + 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; + /* + * 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) { + 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 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; + 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; +} + +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++; + 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; + + /* 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 + +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); +} |