New calls were added to permit a process to create a System V IPC object with a specified SID and to permit a process to obtain the SID of an existing object. New calls were also added to permit a sending process to specify a particular SID for a message and to permit a receiving process to obtain the SID of the received message.
The semsid, msgsid, and shmsid system calls were added to retrieve the security ID for a given semaphore set, message queue, or shared memory segment respectively. The semget_secure, msgget_secure, and shmget_secure system calls were added to provide a way to request an IPC object with a specific security ID.
The msgsnd_secure and msgrcv_secure system calls were added to enable sending and receiving a message with a specific SID to or from a message queue. The msgrcv_secure call takes a SID reference parameter which is either a specific SID to use in selecting a message, or a null or wildcard SID to allow the return of a message at any SID to which access is permitted. The call also returns the SID of the returned message using this reference.