SCM_RIGHTS Transfers File-Descriptor Authority Across Unix Sockets

Thu, 17 Sep 2026 00:00:00 +0000

SCM_RIGHTS Transfers File-Descriptor Authority Across Unix Sockets

A privileged service can open a file that another process could not open by pathname, then pass that access through a Unix-domain socket. The receiving process gets a new file descriptor referring to the same kernel open-file state. No second pathname lookup is required, and the receiver’s ability to open that path is not re-evaluated as part of the transfer.

That property makes SCM_RIGHTS more than an IPC convenience. It moves an already-established kernel capability across a process boundary. Security therefore depends on both sides of the exchange: the sender must constrain which descriptors can leave its authority domain, and the receiver must treat incoming descriptors as privileged objects whose properties require validation.

Unix Socket Peer Credentials Bind Identity to a Local Connection

Thu, 17 Sep 2026 00:00:00 +0000

Unix Socket Peer Credentials Bind Identity to a Local Connection

A privileged local service often accepts requests from processes that share the same host but do not share the same authority. A pathname on a Unix domain socket can control who reaches the listener, yet a successful connection does not by itself tell the service which process is on the other end. Linux provides a second boundary: SO_PEERCRED lets a connected Unix socket expose peer credentials supplied by the kernel.

Unix Sockets on Nalar

SCM_RIGHTS Transfers File-Descriptor Authority Across Unix Sockets

SCM_RIGHTS Transfers File-Descriptor Authority Across Unix Sockets

Unix Socket Peer Credentials Bind Identity to a Local Connection

Unix Socket Peer Credentials Bind Identity to a Local Connection