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authorAl Viro <viro@zeniv.linux.org.uk>2017-07-09 07:57:34 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2017-07-15 20:46:43 -0400
commit156d9ed1260ee566f2be09c13254b58247edfb29 (patch)
tree5a8d98d83a4e557af08d3810a170984ec055f3ab /ipc
parent553f770ef71b27ee053bd241bef0998a15f43467 (diff)
download96b-common-156d9ed1260ee566f2be09c13254b58247edfb29.tar.gz
msgctl(): split the actual work from copyin/copyout
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'ipc')
-rw-r--r--ipc/msg.c202
1 files changed, 96 insertions, 106 deletions
diff --git a/ipc/msg.c b/ipc/msg.c
index 5b25e0755656..322e7bf8b8d1 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -361,23 +361,17 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
* 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 msqid_ds __user *buf, int version)
+ struct msqid64_ds *msqid64)
{
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;
- }
-
down_write(&msg_ids(ns).rwsem);
rcu_read_lock();
ipcp = ipcctl_pre_down_nolock(ns, &msg_ids(ns), msqid, cmd,
- &msqid64.msg_perm, msqid64.msg_qbytes);
+ &msqid64->msg_perm, msqid64->msg_qbytes);
if (IS_ERR(ipcp)) {
err = PTR_ERR(ipcp);
goto out_unlock1;
@@ -399,18 +393,18 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
{
DEFINE_WAKE_Q(wake_q);
- if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
+ 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);
+ err = ipc_update_perm(&msqid64->msg_perm, ipcp);
if (err)
goto out_unlock0;
- msq->q_qbytes = msqid64.msg_qbytes;
+ msq->q_qbytes = msqid64->msg_qbytes;
msq->q_ctime = get_seconds();
/*
@@ -442,111 +436,89 @@ out_up:
return err;
}
-static int msgctl_nolock(struct ipc_namespace *ns, int msqid,
- int cmd, int version, void __user *buf)
+static int msgctl_info(struct ipc_namespace *ns, int msqid,
+ int cmd, struct msginfo *msginfo)
{
int err;
- struct msg_queue *msq;
-
- switch (cmd) {
- case IPC_INFO:
- case MSG_INFO:
- {
- struct msginfo msginfo;
- int max_id;
-
- if (!buf)
- return -EFAULT;
+ int max_id;
- /*
- * 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_id = ipc_get_maxid(&msg_ids(ns));
- up_read(&msg_ids(ns).rwsem);
- if (copy_to_user(buf, &msginfo, sizeof(struct msginfo)))
- return -EFAULT;
- return (max_id < 0) ? 0 : max_id;
+ /*
+ * 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_id = ipc_get_maxid(&msg_ids(ns));
+ up_read(&msg_ids(ns).rwsem);
+ return (max_id < 0) ? 0 : max_id;
+}
- case MSG_STAT:
- case IPC_STAT:
- {
- struct msqid64_ds tbuf;
- int success_return;
-
- if (!buf)
- return -EFAULT;
-
- memset(&tbuf, 0, sizeof(tbuf));
+static int msgctl_stat(struct ipc_namespace *ns, int msqid,
+ int cmd, struct msqid64_ds *p)
+{
+ int err;
+ struct msg_queue *msq;
+ int success_return;
- rcu_read_lock();
- if (cmd == MSG_STAT) {
- msq = msq_obtain_object(ns, msqid);
- if (IS_ERR(msq)) {
- err = PTR_ERR(msq);
- goto out_unlock;
- }
- success_return = msq->q_perm.id;
- } else {
- msq = msq_obtain_object_check(ns, msqid);
- if (IS_ERR(msq)) {
- err = PTR_ERR(msq);
- goto out_unlock;
- }
- success_return = 0;
- }
+ memset(p, 0, sizeof(*p));
- err = -EACCES;
- if (ipcperms(ns, &msq->q_perm, S_IRUGO))
+ rcu_read_lock();
+ if (cmd == MSG_STAT) {
+ msq = msq_obtain_object(ns, msqid);
+ if (IS_ERR(msq)) {
+ err = PTR_ERR(msq);
goto out_unlock;
-
- err = security_msg_queue_msgctl(msq, cmd);
- if (err)
+ }
+ success_return = msq->q_perm.id;
+ } else {
+ msq = msq_obtain_object_check(ns, msqid);
+ if (IS_ERR(msq)) {
+ err = PTR_ERR(msq);
goto out_unlock;
+ }
+ success_return = 0;
+ }
- 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;
- rcu_read_unlock();
+ err = -EACCES;
+ if (ipcperms(ns, &msq->q_perm, S_IRUGO))
+ goto out_unlock;
- if (copy_msqid_to_user(buf, &tbuf, version))
- return -EFAULT;
- return success_return;
- }
+ err = security_msg_queue_msgctl(msq, cmd);
+ if (err)
+ 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;
+ p->msg_cbytes = msq->q_cbytes;
+ p->msg_qnum = msq->q_qnum;
+ p->msg_qbytes = msq->q_qbytes;
+ p->msg_lspid = msq->q_lspid;
+ p->msg_lrpid = msq->q_lrpid;
+ rcu_read_unlock();
- default:
- return -EINVAL;
- }
+ return success_return;
- return err;
out_unlock:
rcu_read_unlock();
return err;
@@ -556,6 +528,8 @@ SYSCALL_DEFINE3(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;
@@ -565,13 +539,29 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
switch (cmd) {
case IPC_INFO:
- case MSG_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 IPC_STAT:
- return msgctl_nolock(ns, msqid, cmd, version, buf);
+ 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, buf, version);
+ return msgctl_down(ns, msqid, cmd, &msqid64);
default:
return -EINVAL;
}