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[PATCH v7 05/10] ipc: add new MSG_SET command for sys_msgctl() call [message #48471] Thu, 18 October 2012 10:23
Stanislav Kinsbursky is currently offline  Stanislav Kinsbursky
Messages: 683
Registered: October 2011
Senior Member
From: *parallels.com
New MSG_SET command will be interpreted exactly as IPC_SET, but also will
update key, cuid and cgid values. IOW, it allows to change existent key value.
The fact, that key is not used is checked before update. Otherwise -EEXIST is
returned.

Signed-off-by: Stanislav Kinsbursky <skinsbursky@parallels.com>
---
include/uapi/linux/msg.h | 1 +
ipc/compat.c | 1 +
ipc/msg.c | 14 ++++++++++++--
security/selinux/hooks.c | 1 +
security/smack/smack_lsm.c | 1 +
5 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/msg.h b/include/uapi/linux/msg.h
index 78dbd2f..76999c9 100644
--- a/include/uapi/linux/msg.h
+++ b/include/uapi/linux/msg.h
@@ -6,6 +6,7 @@
/* ipcs ctl commands */
#define MSG_STAT 11
#define MSG_INFO 12
+#define MSG_SET 13

/* msgrcv options */
#define MSG_NOERROR 010000 /* no error if message is too big */
diff --git a/ipc/compat.c b/ipc/compat.c
index 35c750d..9c70f9a 100644
--- a/ipc/compat.c
+++ b/ipc/compat.c
@@ -483,6 +483,7 @@ long compat_sys_msgctl(int first, int second, void __user *uptr)
break;

case IPC_SET:
+ case MSG_SET:
if (version == IPC_64) {
err = get_compat_msqid64(&m64, uptr);
} else {
diff --git a/ipc/msg.c b/ipc/msg.c
index 2f44946..3c13b99 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -392,6 +392,9 @@ copy_msqid_from_user(struct msqid64_ds *out, void __user *buf, int version)
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;
+ out->msg_perm.cuid = tbuf_old.msg_perm.cuid;
+ out->msg_perm.cgid = tbuf_old.msg_perm.cgid;
+ out->msg_perm.key = tbuf_old.msg_perm.key;

if (tbuf_old.msg_qbytes == 0)
out->msg_qbytes = tbuf_old.msg_lqbytes;
@@ -418,12 +421,13 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
struct msg_queue *msq;
int err;

- if (cmd == IPC_SET) {
+ if (cmd == IPC_SET || cmd == MSG_SET) {
if (copy_msqid_from_user(&msqid64, buf, version))
return -EFAULT;
}

- ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid, cmd,
+ ipcp = ipcctl_pre_down(ns, &msg_ids(ns), msqid,
+ (cmd != MSG_SET) ? cmd : IPC_SET,
&msqid64.msg_perm, msqid64.msg_qbytes);
if (IS_ERR(ipcp))
return PTR_ERR(ipcp);
@@ -438,6 +442,11 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
case IPC_RMID:
freeque(ns, ipcp);
goto out_up;
+ case MSG_SET:
+ err = ipc_update_key(&msg_ids(ns), &msqid64.msg_perm, ipcp);
+ if (err)
+ break;
+ /* fall through */
case IPC_SET:
if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
@@ -569,6 +578,7 @@ SYSCALL_DEFINE3(msgctl, int, msqid, int, cmd, struct msqid_ds __user *, buf)
}
case IPC_SET:
case IPC_RMID:
+ case MSG_SET:
err = msgctl_down(ns, msqid, cmd, buf, version);
return err;
default:
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index 62b2447..78b77ac 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -4885,6 +4885,7 @@ static int selinux_msg_queue_msgctl(struct msg_queue *msq, int cmd)
perms = MSGQ__GETATTR | MSGQ__ASSOCIATE;
break;
case IPC_SET:
+ case MSG_SET:
perms = MSGQ__SETATTR;
break;
case IPC_RMID:
diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
index c7eabc9..d51a8da 100644
--- a/security/smack/smack_lsm.c
+++ b/security/smack/smack_lsm.c
@@ -2374,6 +2374,7 @@ static int smack_msg_queue_msgctl(struct msg_queue *msq, int cmd)
may = MAY_READ;
break;
case IPC_SET:
+ case MSG_SET:
case IPC_RMID:
may = MAY_READWRITE;
break;
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