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[PATCH v6 05/10] ipc: add new MSG_SET command for sys_msgctl() call [message #48353] Mon, 15 October 2012 16:00 Go to next message
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 | 13 +++++++++++--
security/selinux/hooks.c | 1 +
security/smack/smack_lsm.c | 1 +
5 files changed, 15 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..68515dc 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);
@@ -439,6 +443,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
freeque(ns, ipcp);
goto out_up;
case IPC_SET:
+ case MSG_SET:
if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
!capable(CAP_SYS_RESOURCE)) {
err = -EPERM;
@@ -451,6 +456,9 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,

msq->q_qbytes = msqid64.msg_qbytes;

+ if (cmd == MSG_SET)
+ ipc_update_key(&msg_ids(ns), &msqid64.msg_perm, ipcp);
+
msq->q_ctime = get_seconds();
/* sleeping receivers might be excluded by
* stricter permissions.
@@ -569,6 +577,7 @@ 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;
Re: [PATCH v6 05/10] ipc: add new MSG_SET command for sys_msgctl() call [message #48569 is a reply to message #48353] Tue, 23 October 2012 16:29 Go to previous message
Serge E. Hallyn is currently offline  Serge E. Hallyn
Messages: 26
Registered: February 2011
Junior Member
From: *parallels.com
Quoting Stanislav Kinsbursky (skinsbursky@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>

Acked-by: Serge E. Hallyn <serge.hallyn@ubuntu.com>

> ---
> include/uapi/linux/msg.h | 1 +
> ipc/compat.c | 1 +
> ipc/msg.c | 13 +++++++++++--
> security/selinux/hooks.c | 1 +
> security/smack/smack_lsm.c | 1 +
> 5 files changed, 15 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..68515dc 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);
> @@ -439,6 +443,7 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
> freeque(ns, ipcp);
> goto out_up;
> case IPC_SET:
> + case MSG_SET:
> if (msqid64.msg_qbytes > ns->msg_ctlmnb &&
> !capable(CAP_SYS_RESOURCE)) {
> err = -EPERM;
> @@ -451,6 +456,9 @@ static int msgctl_down(struct ipc_namespace *ns, int msqid, int cmd,
>
> msq->q_qbytes = msqid64.msg_qbytes;
>
> + if (cmd == MSG_SET)
> + ipc_update_key(&msg_ids(ns), &msqid64.msg_perm, ipcp);
> +
> msq->q_ctime = get_seconds();
> /* sleeping receivers might be excluded by
> * stricter permissions.
> @@ -569,6 +577,7 @@ 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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