/*
* This function handles some msgctl commands which require the rw_mutex
* to be held in write mode.
* NOTE: no locks must be held, the rw_mutex is taken inside this function.
*/
static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
struct msqid_ds __user *buf, int version)
{
struct kern_ipc_perm *ipcp;
struct msqid64_ds uninitialized_var(msqid64);
struct msg_queue *msq;
int err;
if (cmd == IPC_SET) {
if (copy_msqid_from_user(&msqid64, buf, version))
return -EFAULT;
}
ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
&msqid64.msg_perm, msqid64.msg_qbytes);
if (IS_ERR(ipcp))
return PTR_ERR(ipcp);
msq = container_of(ipcp, struct msg_queue, q_perm);
err = security_msg_queue_msgctl(msq, cmd);
if (err)
goto out_unlock;
switch (cmd) {
case IPC_RMID:
freeque(ns, ipcp);
goto out_up;
case IPC_SET:
if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
err = -EPERM;
goto out_unlock;
}
err = ipc_update_perm(&msqid64.msg_perm, ipcp);
if (err)
goto out_unlock;
msq->q_qbytes = msqid64.msg_qbytes;
msq->q_ctime = get_seconds();
/* sleeping receivers might be excluded by
* stricter permissions.
*/
expunge_all(msq, -EAGAIN);
/* sleeping senders might be able to send
* due to a larger queue size.
*/
ss_wakeup(&msq->q_senders, 0);
break;
default:
err = -EINVAL;
}
out_unlock:
msg_unlock(msq);
out_up:
up_write(&msg_ids(ns).rw_mutex);
return err;
}
SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
{
struct msg_queue *msq;
int err, version;
struct ipc_namespace *ns;
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;
int max_id;
if (!buf)
return -EFAULT;
/*
* 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).rw_mutex);
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_id = ipc_get_maxid(&msg_ids(ns));
up_read(&msg_ids(ns).rw_mutex);
if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0 : max_id;
}
case MSG_STAT: /* msqid is an index rather than a msg queue id */
case IPC_STAT:
{
struct msqid64_ds tbuf;
int success_return;
if (!buf)
return -EFAULT;
if (cmd == MSG_STAT) {
msq = msg_lock(ns, msqid);
if (IS_ERR(msq))
return PTR_ERR(msq);
success_return = msq->q_perm.id;
} else {
msq = msg_lock_check(ns, msqid);
if (IS_ERR(msq))
return PTR_ERR(msq);
success_return = 0;
}
err = -EACCES;
if (ipcperms(&msq->q_perm, S_IRUGO))
goto out_unlock;
err = security_msg_queue_msgctl(msq, cmd);
if (err)
goto out_unlock;
memset(&tbuf, 0, sizeof(tbuf));
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
tbuf.msg_stime = msq->q_stime;
tbuf.msg_rtime = msq->q_rtime;
tbuf.msg_ctime = msq->q_ctime;
tbuf.msg_cbytes = msq->q_cbytes;
tbuf.msg_qnum = msq->q_qnum;
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
msg_unlock(msq);
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
return success_return;
}
case IPC_SET:
case IPC_RMID:
err = msgctl_down(ns, msqid, cmd, buf, version);
return err;
default:
return -EINVAL;
}
out_unlock:
msg_unlock(msq);
return err;
}
asmlinkage long sys_msgctl (int msqid, int cmd, struct msqid_ds __user *buf)
{
int err, version;
struct msg_queue *msq;
struct msq_setbuf setbuf;
struct kern_ipc_perm *ipcp;
if (msqid < 0 || cmd < 0)
return -EINVAL;
version = ipc_parse_version(&cmd);
switch (cmd) {
case IPC_INFO:
case MSG_INFO:
{
struct msginfo msginfo;
int max_id;
if (!buf)
return -EFAULT;
/* 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 = msg_ctlmni;
msginfo.msgmax = msg_ctlmax;
msginfo.msgmnb = msg_ctlmnb;
msginfo.msgssz = MSGSSZ;
msginfo.msgseg = MSGSEG;
down(&msg_ids.sem);
if (cmd == MSG_INFO) {
msginfo.msgpool = msg_ids.in_use;
msginfo.msgmap = atomic_read(&msg_hdrs);
msginfo.msgtql = atomic_read(&msg_bytes);
} else {
msginfo.msgmap = MSGMAP;
msginfo.msgpool = MSGPOOL;
msginfo.msgtql = MSGTQL;
}
max_id = msg_ids.max_id;
up(&msg_ids.sem);
if (copy_to_user (buf, &msginfo, sizeof(struct msginfo)))
return -EFAULT;
return (max_id < 0) ? 0: max_id;
}
case MSG_STAT:
case IPC_STAT:
{
struct msqid64_ds tbuf;
int success_return;
if (!buf)
return -EFAULT;
if(cmd == MSG_STAT && msqid >= msg_ids.size)
return -EINVAL;
memset(&tbuf,0,sizeof(tbuf));
msq = msg_lock(msqid);
if (msq == NULL)
return -EINVAL;
if(cmd == MSG_STAT) {
success_return = msg_buildid(msqid, msq->q_perm.seq);
} else {
err = -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock;
success_return = 0;
}
err = -EACCES;
if (ipcperms (&msq->q_perm, S_IRUGO))
goto out_unlock;
err = security_msg_queue_msgctl(msq, cmd);
if (err)
goto out_unlock;
kernel_to_ipc64_perm(&msq->q_perm, &tbuf.msg_perm);
tbuf.msg_stime = msq->q_stime;
tbuf.msg_rtime = msq->q_rtime;
tbuf.msg_ctime = msq->q_ctime;
tbuf.msg_cbytes = msq->q_cbytes;
tbuf.msg_qnum = msq->q_qnum;
tbuf.msg_qbytes = msq->q_qbytes;
tbuf.msg_lspid = msq->q_lspid;
tbuf.msg_lrpid = msq->q_lrpid;
msg_unlock(msq);
if (copy_msqid_to_user(buf, &tbuf, version))
return -EFAULT;
return success_return;
}
case IPC_SET:
if (!buf)
return -EFAULT;
if (copy_msqid_from_user (&setbuf, buf, version))
return -EFAULT;
break;
case IPC_RMID:
break;
default:
return -EINVAL;
}
down(&msg_ids.sem);
msq = msg_lock(msqid);
err=-EINVAL;
if (msq == NULL)
goto out_up;
err = -EIDRM;
if (msg_checkid(msq,msqid))
goto out_unlock_up;
ipcp = &msq->q_perm;
err = -EPERM;
if (current->euid != ipcp->cuid &&
current->euid != ipcp->uid && !capable(CAP_SYS_ADMIN))
/* We _could_ check for CAP_CHOWN above, but we don't */
goto out_unlock_up;
err = security_msg_queue_msgctl(msq, cmd);
if (err)
goto out_unlock_up;
switch (cmd) {
case IPC_SET:
{
err = -EPERM;
if (setbuf.qbytes > msg_ctlmnb && !capable(CAP_SYS_RESOURCE))
goto out_unlock_up;
msq->q_qbytes = setbuf.qbytes;
ipcp->uid = setbuf.uid;
ipcp->gid = setbuf.gid;
ipcp->mode = (ipcp->mode & ~S_IRWXUGO) |
(S_IRWXUGO & setbuf.mode);
msq->q_ctime = get_seconds();
/* sleeping receivers might be excluded by
* stricter permissions.
*/
expunge_all(msq,-EAGAIN);
/* sleeping senders might be able to send
* due to a larger queue size.
*/
ss_wakeup(&msq->q_senders,0);
msg_unlock(msq);
break;
}
case IPC_RMID:
freeque (msq, msqid);
break;
}
err = 0;
out_up:
up(&msg_ids.sem);
return err;
out_unlock_up:
msg_unlock(msq);
goto out_up;
out_unlock:
msg_unlock(msq);
return err;
}